* Re: [PATCH v4 09/23] ext4: implement writeback path using iomap
From: Jan Kara @ 2026-06-24 17:16 UTC (permalink / raw)
To: Zhang Yi
Cc: Jan Kara, Zhang Yi, linux-ext4, linux-fsdevel, linux-kernel,
tytso, adilger.kernel, libaokun, ojaswin, ritesh.list, djwong,
hch, yi.zhang, yangerkun, yukuai
In-Reply-To: <b0781809-4759-4e12-be17-71555b764f48@gmail.com>
On Mon 22-06-26 20:36:02, Zhang Yi wrote:
> On 6/16/2026 7:47 PM, Jan Kara wrote:
> > On Mon 11-05-26 15:23:29, Zhang Yi wrote:
> > > From: Zhang Yi <yi.zhang@huawei.com>
> > >
> > > Add the iomap writeback path for ext4 buffered I/O. This introduces:
> > >
> > > - ext4_iomap_writepages(): the main writeback entry point.
> > > - ext4_writeback_ops: a new iomap_writeback_ops instance to handle
> > > block mapping and I/O submission.
> > > - A new end I/O worker for converting unwritten extents, updating file
> > > size, and handling DATA_ERR_ABORT after I/O completion.
> > >
> > > Core implementation details:
> > >
> > > - ->writeback_range() callback
> > > Calls ext4_iomap_map_writeback_range() to query the longest range of
> > > existing mapped extents. For performance, when a block range is not
> > > yet allocated, it allocates based on the writeback length and delalloc
> > > extent length, rather than allocating for a single folio at a time.
> > > The folio is then added to an iomap_ioend instance.
> > >
> > > - ->writeback_submit() callback
> > > Registers ext4_iomap_end_bio() as the end bio callback. This callback
> > > schedules a worker to handle:
> > > - Unwritten extent conversion.
> > > - i_disksize update after data is written back.
> > > - Journal abort on writeback I/O failure.
> > >
> > > Key changes and considerations:
> > >
> > > - Append write and unwritten extents
> > > Since data=ordered mode is not used to prevent stale data exposure
> > > during append writebacks, new blocks are always allocated as unwritten
> > > extents (i.e. always enable dioread_nolock), and i_disksize update is
> > > postponed until I/O completion. Additionally, the deadlock that the
> > > reserve handle was expected to resolve does not occur anymore.
> > > Therefore, the end I/O worker can start a normal journal handle
> > > instead of a reserve handle when converting unwritten extents.
> > >
> > > - Lock ordering
> > > The ->writeback_range() callback runs under the folio lock, requiring
> > > the journal handle to be started under that same lock. This reverses
> > > the order compared to the buffer_head writeback path. The lock ordering
> > > documentation in super.c has been updated accordingly.
> > >
> > > Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
> > > ---
> > > fs/ext4/ext4.h | 4 +
> > > fs/ext4/inode.c | 208 +++++++++++++++++++++++++++++++++++++++++-
> > > fs/ext4/page-io.c | 126 +++++++++++++++++++++++++
> > > fs/ext4/super.c | 7 +-
> > > fs/iomap/ioend.c | 3 +-
> > > include/linux/iomap.h | 1 +
> > > 6 files changed, 346 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> > > index 4832e7f7db82..078feda47e36 100644
> > > --- a/fs/ext4/ext4.h
> > > +++ b/fs/ext4/ext4.h
> > > @@ -1173,6 +1173,8 @@ struct ext4_inode_info {
> > > */
> > > struct list_head i_rsv_conversion_list;
> > > struct work_struct i_rsv_conversion_work;
> > > + struct list_head i_iomap_ioend_list;
> > > + struct work_struct i_iomap_ioend_work;
> >
> > Ugh, this adds 48 bytes to ext4 inode. That's pretty heavy. Cannot we reuse
> > i_rsv_conversion_list / work for this? For each inode only one of them
> > should be used AFAICS.
>
> Thanks for your suggestion. I think we should be able to reuse
> i_rsv_conversion_list / work. We can choose the corresponding
> initialization function for i_rsv_conversion_work based on the buffered
> write path at initialization time, and then reinitialize the work
> handler when changing the path via the ioctl that sets the journal
> flag. That should be sufficient.
Great, thanks.
> > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> > > index 1ae7d3f4a1c8..a80195bd6f20 100644
> > > --- a/fs/ext4/inode.c
> > > +++ b/fs/ext4/inode.c
> > > @@ -44,6 +44,7 @@
> > > #include <linux/iversion.h>
> > > #include "ext4_jbd2.h"
> > > +#include "ext4_extents.h"
> > > #include "xattr.h"
> > > #include "acl.h"
> > > #include "truncate.h"
> > > @@ -4120,10 +4121,215 @@ static void ext4_iomap_readahead(struct readahead_control *rac)
> > > iomap_bio_readahead(rac, &ext4_iomap_buffered_read_ops);
> > > }
> > > +static int ext4_iomap_map_one_extent(struct inode *inode,
> > > + struct ext4_map_blocks *map)
> > > +{
> > > + struct extent_status es;
> > > + handle_t *handle = NULL;
> > > + int credits, map_flags;
> > > + int retval;
> > > +
> > > + credits = ext4_chunk_trans_blocks(inode, map->m_len);
> > > + handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, credits);
> > > + if (IS_ERR(handle))
> > > + return PTR_ERR(handle);
> > > +
> > > + map->m_flags = 0;
> > > + /*
> > > + * It is necessary to look up extent and map blocks under i_data_sem
> > > + * in write mode, otherwise, the delalloc extent may become stale
> > > + * during concurrent truncate operations.
> > > + */
> > > + ext4_fc_track_inode(handle, inode);
> > > + down_write(&EXT4_I(inode)->i_data_sem);
> > > + if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es, &map->m_seq)) {
> > > + retval = es.es_len - (map->m_lblk - es.es_lblk);
> > > + map->m_len = min_t(unsigned int, retval, map->m_len);
> > > +
> > > + if (ext4_es_is_delayed(&es)) {
> > > + map->m_flags |= EXT4_MAP_DELAYED;
> > > + trace_ext4_da_write_pages_extent(inode, map);
> > > + /*
> > > + * Call ext4_map_create_blocks() to allocate any
> > > + * delayed allocation blocks. It is possible that
> > > + * we're going to need more metadata blocks, however
> > > + * we must not fail because we're in writeback and
> > > + * there is nothing we can do so it might result in
> > > + * data loss. So use reserved blocks to allocate
> > > + * metadata if possible.
> > > + */
> > > + map_flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT |
> > > + EXT4_GET_BLOCKS_METADATA_NOFAIL |
> > > + EXT4_EX_NOCACHE;
> > > +
> > > + retval = ext4_map_create_blocks(handle, inode, map,
> > > + map_flags);
> > > + if (retval > 0)
> > > + ext4_fc_track_range(handle, inode, map->m_lblk,
> > > + map->m_lblk + map->m_len - 1);
> > > + goto out;
> > > + } else if (unlikely(ext4_es_is_hole(&es)))
> > > + goto out;
> > > +
> > > + /* Found written or unwritten extent. */
> > > + map->m_pblk = ext4_es_pblock(&es) + map->m_lblk - es.es_lblk;
> > > + map->m_flags = ext4_es_is_written(&es) ?
> > > + EXT4_MAP_MAPPED : EXT4_MAP_UNWRITTEN;
> > > + goto out;
> > > + }
> > > +
> > > + retval = ext4_map_query_blocks(handle, inode, map, EXT4_EX_NOCACHE);
> > > +out:
> > > + up_write(&EXT4_I(inode)->i_data_sem);
> > > + ext4_journal_stop(handle);
> > > + return retval < 0 ? retval : 0;
> > > +}
> > > +
> > > +static int ext4_iomap_map_writeback_range(struct iomap_writepage_ctx *wpc,
> > > + loff_t offset, unsigned int dirty_len)
> > > +{
> > > + struct inode *inode = wpc->inode;
> > > + struct super_block *sb = inode->i_sb;
> > > + struct journal_s *journal = EXT4_SB(sb)->s_journal;
> > > + struct ext4_map_blocks map;
> > > + unsigned int blkbits = inode->i_blkbits;
> > > + unsigned int index = offset >> blkbits;
> > > + unsigned int blk_end, blk_len;
> > > + int ret;
> > > +
> > > + ret = ext4_emergency_state(sb);
> > > + if (unlikely(ret))
> > > + return ret;
> > > +
> > > + /* Check validity of the cached writeback mapping. */
> > > + if (offset >= wpc->iomap.offset &&
> > > + offset < wpc->iomap.offset + wpc->iomap.length &&
> > > + ext4_iomap_valid(inode, &wpc->iomap))
> > > + return 0;
> > > +
> > > + blk_len = dirty_len >> blkbits;
> > > + blk_end = min_t(unsigned int, (wpc->wbc->range_end >> blkbits),
> > > + (UINT_MAX - 1));
> > > + if (blk_end > index + blk_len)
> > > + blk_len = blk_end - index + 1;
> > > +
> > > +retry:
> > > + map.m_lblk = index;
> > > + map.m_len = min_t(unsigned int, MAX_WRITEPAGES_EXTENT_LEN, blk_len);
> > > + ret = ext4_map_blocks(NULL, inode, &map,
> > > + EXT4_GET_BLOCKS_IO_SUBMIT | EXT4_EX_NOCACHE);
> > > + if (ret < 0)
> > > + return ret;
> > > +
> > > + /*
> > > + * The map is not a delalloc extent, it must either be a hole
> > > + * or an extent which have already been allocated.
> > > + */
> > > + if (!(map.m_flags & EXT4_MAP_DELAYED))
> > > + goto out;
> > > +
> > > + /* Map one delalloc extent. */
> > > + ret = ext4_iomap_map_one_extent(inode, &map);
> >
> > So it looks somewhat strange that here we call ext4_map_blocks() (which
> > consults extent status tree and then possibly on-disk extent tree) and then
> > we call ext4_iomap_map_one_extent() which manipulates with the extent
> > status tree and possibly extent tree as well. Is all this complexity to
> > avoid starting a jbd2 handle unless really needed? If yes, is that really
> > worth it? Given iomap code caches the extent we'd start the transaction
> > only once per mapped extent which shouldn't be that bad?
> >
> > If you have some benchmark showing this is really worth it,
>
> There are actually two reasons for this. First, we want to avoid
> starting a journal handle in overwrite scenarios. Second, we want to
> be able to query the extent locklessly without holding i_data_sem in
> overwrite cases as well (note that ext4_es_lookup_extent() in
> ext4_iomap_map_one_extent() is called with i_data_sem held).
>
> I ran a set of benchmark tests in my VM, performing the following FIO
> overwrite test on a 500GB ramdisk:
>
> $fio -filename=/test_dir/foo -direct=0 -iodepth=8 -fsync=0 -rw=write \
> -numjobs=1 -bs=4k -ioengine=io_uring -size=20G -uncached=1 \
> -runtime=30 --ramp_time=5s -time_based -norandommap=0 \
> -fallocate=none -overwrite=1 \
> -group_reportin -name=test --output=/tmp/log
>
> The results are as follows:
>
> a: on a non-fragmented file
> A: on a fragmented file [1]
> b: no background metadata pressure
> B: with background metadata pressure [2]
>
> buffer_head | iomap pre-map w/o journal | iomap directly map
> a+b: 680 691 690
> a+B: 560 568 567
> A+b: 637 633 579
> A+B: 540 571 495
>
> [1] The file is pre-fragmented such that each block occupies a separate
> extent.
> [2] A background fsstress process is running (only contains metadata
> ops):
> taskset -c 2 fsstress -c -d /test_dir -l 0 -n 1000 -f clonerange=0 \
> -f copyrange=0 -f awrite=0 -f aread=0 -f dread=0 \
> -f dwrite=0 -f mread=0 -f mwrite=0 -f readv=0 -f write=0 \
> -f writev=0 -f read=0 -f sync=0 -f afsync=0 -f fsync=0
>
> As can be seen, for large contiguous files, the performance impact is
> minimal. However, in heavily fragmented scenarios or under other
> metadata pressure, pre-querying the mapping brings noticeable gains.
> However, this is testing the most extreme case — I'm not sure about
> the real-world impact, so I don't have a strong preference either way.
> But I suppose faster is better, at least not slower than the old
> buffer_head path. :)
OK, thanks for the test! So for fragmented files the optimization of not
starting a transaction seems indeed worth it. I still dislike the
opencoding :) So given we have the reversed lock ordering now, why don't we
teach ext4_map_blocks() to start a transaction (if not provided) just
before it acquires i_data_sem for writing? This should be quite elegant. I
know you have some concerns about possible races below so let's discuss
that separately but at least in terms of performance and code complexity
this would look ideal :).
> > then I'd
> > probably prefer coming up with an ext4_get_blocks flag which tells it to
> > start a transaction on its own if we need to allocate blocks... That would
> > be much simpler than opencoding all this.
>
> Additionally, there is a key point here. The reason I open-coded
> ext4_iomap_map_writeback_range() is that we must ensure extent query
> and allocation are performed atomically under i_data_sem. Otherwise,
> concurrent truncate could lead to quota leaks.
>
> Specifically, consider the following scenario: we call
> ext4_map_blocks() to allocate blocks. Suppose there is a delalloc
> extent covering blocks [0,3). While writeback is submitting block 0, a
> concurrent truncate(block 1) occurs:
>
> wb truncate
> ext4_es_lookup_extent() ext4_truncate_down()
> //get [0,3)
> truncate_inode_pages_range()
> //clear page 1&2
> ext4_truncate()
> down_write(i_data_sem)
> ext4_es_remove_extent()
> //drop extent [1,3)
> //i_reserved_data_blocks: 3->1
> up_write(i_data_sem)
> down_write(i_data_sem)
> ext4_map_create_blocks()
> //alloc 3 blocks
> ext4_es_insert_extent()
> //only reclaim 1 block，stale 2 blocks
> up_write(i_data_sem)
>
> Therefore, If we don't open-coding this part, we would need to
> significantly rework ext4_map_blocks(), which might have a larger
> impact at this point. What do you think?
Hum, is something like this really possible? I mean iomap_writepages() will
lookup and lock folio. Only then it calls ->iomap_begin to map it to
underlying blocks. And folio lock synchronizes against
truncate_inode_pages_range() so how would writeback end up trying to
allocate something underlying pages 1 or 2?
> > > + if (ret < 0) {
> > > + if (ext4_emergency_state(sb))
> > > + return ret;
> > > +
> > > + /*
> > > + * Retry transient ENOSPC errors, if
> > > + * ext4_count_free_blocks() is non-zero, a commit
> > > + * should free up blocks.
> > > + */
> > > + if (ret == -ENOSPC && journal && ext4_count_free_clusters(sb)) {
> > > + jbd2_journal_force_commit_nested(journal);
> > > + goto retry;
> > > + }
> > > +
> > > + ext4_msg(sb, KERN_CRIT,
> > > + "Delayed block allocation failed for inode %llu at logical offset %llu with max blocks %u with error %d",
> > > + inode->i_ino, (unsigned long long)map.m_lblk,
> > > + (unsigned int)map.m_len, -ret);
> > > + ext4_msg(sb, KERN_CRIT,
> > > + "This should not happen!! Data will be lost\n");
> > > + if (ret == -ENOSPC)
> > > + ext4_print_free_blocks(inode);
> > > + return ret;
> > > + }
> > > +out:
> > > + ext4_set_iomap(inode, &wpc->iomap, &map, offset, dirty_len, 0);
> > > + return 0;
> > > +}
> > > +
> >
> > ...
> >
> > > +void ext4_iomap_end_bio(struct bio *bio)
> > > +{
> > > + struct iomap_ioend *ioend = iomap_ioend_from_bio(bio);
> > > + struct inode *inode = ioend->io_inode;
> > > + struct ext4_inode_info *ei = EXT4_I(inode);
> > > + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
> > > + unsigned long flags;
> > > +
> > > + /* Needs to convert unwritten extents or update the i_disksize. */
> > > + if ((ioend->io_flags & IOMAP_IOEND_UNWRITTEN) ||
> > > + ioend->io_offset + ioend->io_size > READ_ONCE(ei->i_disksize))
> > > + goto defer;
> > > +
> > > + /* Needs to abort the journal on data_err=abort. */
> > > + if (unlikely(ioend->io_bio.bi_status))
> > > + goto defer;
> > > +
> > > + iomap_finish_ioend(ioend, 0);
> > > + return;
> > > +defer:
> > > + spin_lock_irqsave(&ei->i_completed_io_lock, flags);
> > > + if (list_empty(&ei->i_iomap_ioend_list))
> > > + queue_work(sbi->rsv_conversion_wq, &ei->i_iomap_ioend_work);
> > > + list_add_tail(&ioend->io_list, &ei->i_iomap_ioend_list);
> > > + spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
> > > +}
> >
> > For now, I'd prefer to do what XFS does and offload everything. Then you
> > don't have to export iomap_finish_ioend() (which would need to be in a
> > separate patch and acked by iomap maintainers) and the code is more
> > standard. There's a patchset in the works which adds general ioend offloading
> > infrastructure into iomap [1] and when that lands we should get all these
> ^^^^^ block layer?
>
> > bells and whistles (even better ones with percpu work queues, batching,
> > etc.) for free.
> >
> > [1] https://lore.kernel.org/all/20260514-blk-dontcache-v6-0-782e2fa7477b@columbia.edu/
> >
> > Honza
>
> Ha, I've noticed this patchset, so I haven't implemented
> uncached I/O handling for now. As a side note, I have a question:
> if we convert all endio processing to worker threads, IIRC, my
> recollection from previous performance tests is that pure overwrite
> scenarios would see at least a 20% degradation. Is that acceptable?
No, but the latest version of the patches exactly does IO completion in the
interrupt unless the bio is flagged as needing IO completion from process
context or unless end_io handler returns a particular error - which means
IO completion wasn't actually done and needs offloading into process
context instead.
> I understand why uncached I/O might need the entire completion path
> in a worker, but can we complete the I/O in interrupt context for
> pure overwrite and then release the page cache in a worker? Must
> page cache invalidation and I/O completion be synchronous?
Strictly speaking no, we can first complete the IO and evict page cache
independently later. But it would be quite tricky locking wise (folios and
the mapping containing them can get evicted once folio writeback bit gets
cleared) so the whole uncached writes handling would have to be reworked. I
don't think it's worth it at this point.
> The reason I kept ext4_iomap_end_bio() handling I/O completion in
> interrupt context is for overwrite performance. XFS also handles
> overwrites in interrupt context (via ioend_writeback_end_bio()).
> However, ext4 has the data_error=abort mount option — when this mode
> is set and an I/O error occurs, we must abort the journal in a
> worker. Since we cannot predict I/O errors at submission time, we
> can't directly use ioend_writeback_end_bio() and must instead bind
> our own ext4_iomap_end_bio(). At the same time, I want to avoid
> spawning a worker for pure overwrites when no I/O error occurs, so I
> exported iomap_finish_ioend(). What do you think?
So data_error=abort handling can exactly use the new generic framework - if
we detect during processing IO completion we cannot actually do it in the
interrupt (like in case of error), we just return appropriately from the
handler and the generic code will handle offloading and call the ->end_io
callback again.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
^ permalink raw reply
* Re: [PATCH v4] iomap: add simple read path for small direct I/O
From: Christoph Hellwig @ 2026-06-24 15:37 UTC (permalink / raw)
To: Fengnan Chang
Cc: brauner, djwong, hch, ojaswin, dgc, linux-xfs, linux-fsdevel,
linux-ext4, linux-kernel, lidiangang
In-Reply-To: <20260608073134.95964-1-changfengnan@bytedance.com>
Sorry for the delay in getting back to this, I'm a bit overloaded at
the moment.
> -static inline bool should_report_dio_fserror(const struct iomap_dio *dio)
> +static inline bool should_report_dio_fserror(int error)
Can you split all the refactoring into prep patches?
> +/*
> + * In the async simple read path, we need to prevent bio_endio() from
> + * triggering iocb->ki_complete() before the submitter has returned
> + * -EIOCBQUEUED. Otherwise, the caller might free the iocb concurrently.
> + *
> + * We use a three-state rendezvous to synchronize the submitter and end_io:
> + *
> + * IOMAP_DIO_SIMPLE_SUBMITTING: Initial state set before submitting the bio.
> + *
> + * IOMAP_DIO_SIMPLE_QUEUED: The submitter has safely queued the IO and will
> + * return -EIOCBQUEUED. If end_io sees this state, it takes over and calls
> + * ki_complete().
> + *
> + * IOMAP_DIO_SIMPLE_DONE: end_io fired before the submitter finished the
> + * submit path. end_io sets this state and does nothing else. The submitter
> + * will see this state and handle the completion synchronously (bypassing
> + * ki_complete() and returning the actual result).
> + */
I don't think we actually need any of this. For the sync case we
can just use submit_bio_wait, and for async just always complete
from the end_io handler. This will simplify the implementation a lot,
and also avoid the atomic.
> +static void iomap_dio_simple_read_async_done(struct iomap_dio_simple_read *sr)
Btw, I'd drop the _read in the name. Most of this would work as-is
for trivial overwrites if we figure out when to use them.
> + if (dio_flags & IOMAP_DIO_BOUNCE)
> + nr_pages = bio_iov_bounce_nr_vecs(iter, REQ_OP_READ);
> + else
> + nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);
Bounce buffering requires dops, so all this can be dropped.
> + ret = ops->iomap_begin(inode, iomi.pos, count, iomi.flags,
> + &iomi.iomap, &iomi.srcmap);
> + if (ret) {
> + inode_dio_end(inode);
> + return ret;
> + }
> +
> + if (iomi.iomap.type != IOMAP_MAPPED ||
> + iomi.iomap.offset > iomi.pos ||
I don't think offset > pos can happen
> + iomi.iomap.offset + iomi.iomap.length < iomi.pos + count ||
> + (iomi.iomap.flags & IOMAP_F_INTEGRITY)) {
> + ret = -ENOTBLK;
> + goto out_iomap_end;
> + }
Given that we already have a fallback here, I'm not sure why this is
limited to a single file system block. Anything that:
a) fits into the iomap
b) fits into a single bio
can be easily supported. The first condition is a trivial, and for
the second we could just check if iter->nr_segs is larger than
BIO_MAX_VECS.
> + if (user_backed_iter(iter))
> + dio_flags |= IOMAP_DIO_USER_BACKED;
> + bio->bi_iter.bi_sector = iomap_sector(&iomi.iomap, iomi.pos);
> + bio->bi_ioprio = iocb->ki_ioprio;
> + bio->bi_private = sr;
> + bio->bi_end_io = iomap_dio_simple_read_end_io;
> +
> + if ((dio_flags & IOMAP_DIO_USER_BACKED) &&
> + !(dio_flags & IOMAP_DIO_BOUNCE))
> + bio_set_pages_dirty(bio);
> +
> + if (iocb->ki_flags & IOCB_NOWAIT)
> + bio->bi_opf |= REQ_NOWAIT;
> + if ((iocb->ki_flags & IOCB_HIPRI) && !wait_for_completion) {
> + bio->bi_opf |= REQ_POLLED;
> + bio_set_polled(bio, iocb);
> + WRITE_ONCE(iocb->private, bio);
> + }
Can you check if sone more of this can be factored into a shared
helper?
Below is a completely untested patch implementing my suggestion
for the completion simplification. It compiles, but that's about
the guarantees I can give for it:
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 3cb179752612..c785512e5339 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -909,11 +909,7 @@ struct iomap_dio_simple_read {
struct kiocb *iocb;
size_t size;
unsigned int dio_flags;
- atomic_t state;
- union {
- struct task_struct *waiter;
- struct work_struct work;
- };
+ struct work_struct work;
/*
* Align @bio to a cacheline boundary so that, combined with the
* front_pad passed to bioset_init(), the bio sits at the start of
@@ -926,35 +922,12 @@ struct iomap_dio_simple_read {
static struct bio_set iomap_dio_simple_read_pool;
-/*
- * In the async simple read path, we need to prevent bio_endio() from
- * triggering iocb->ki_complete() before the submitter has returned
- * -EIOCBQUEUED. Otherwise, the caller might free the iocb concurrently.
- *
- * We use a three-state rendezvous to synchronize the submitter and end_io:
- *
- * IOMAP_DIO_SIMPLE_SUBMITTING: Initial state set before submitting the bio.
- *
- * IOMAP_DIO_SIMPLE_QUEUED: The submitter has safely queued the IO and will
- * return -EIOCBQUEUED. If end_io sees this state, it takes over and calls
- * ki_complete().
- *
- * IOMAP_DIO_SIMPLE_DONE: end_io fired before the submitter finished the
- * submit path. end_io sets this state and does nothing else. The submitter
- * will see this state and handle the completion synchronously (bypassing
- * ki_complete() and returning the actual result).
- */
-enum {
- IOMAP_DIO_SIMPLE_SUBMITTING = 0,
- IOMAP_DIO_SIMPLE_QUEUED,
- IOMAP_DIO_SIMPLE_DONE,
-};
-
-static ssize_t iomap_dio_simple_read_finish(struct kiocb *iocb,
- struct bio *bio, ssize_t ret)
+static ssize_t iomap_dio_simple_read_complete(struct iomap_dio_simple_read *sr)
{
+ struct bio *bio = &sr->bio;
+ struct kiocb *iocb = sr->iocb;
struct inode *inode = file_inode(iocb->ki_filp);
- struct iomap_dio_simple_read *sr = bio->bi_private;
+ ssize_t ret = blk_status_to_errno(bio->bi_status);
if (likely(!ret)) {
ret = sr->size;
@@ -965,21 +938,6 @@ static ssize_t iomap_dio_simple_read_finish(struct kiocb *iocb,
}
iomap_dio_bio_release_pages(bio, sr->dio_flags, ret < 0);
-
- return ret;
-}
-
-static ssize_t iomap_dio_simple_read_complete(struct kiocb *iocb,
- struct bio *bio)
-{
- struct inode *inode = file_inode(iocb->ki_filp);
- ssize_t ret;
-
- WRITE_ONCE(iocb->private, NULL);
-
- ret = iomap_dio_simple_read_finish(iocb, bio,
- blk_status_to_errno(bio->bi_status));
-
inode_dio_end(inode);
trace_iomap_dio_complete(iocb, ret < 0 ? ret : 0, ret > 0 ? ret : 0);
return ret;
@@ -988,45 +946,26 @@ static ssize_t iomap_dio_simple_read_complete(struct kiocb *iocb,
static void iomap_dio_simple_read_complete_work(struct work_struct *work)
{
struct iomap_dio_simple_read *sr =
- container_of(work, struct iomap_dio_simple_read, work);
- struct kiocb *iocb = sr->iocb;
- ssize_t ret;
+ container_of(work, struct iomap_dio_simple_read, work);
- ret = iomap_dio_simple_read_complete(iocb, &sr->bio);
- iocb->ki_complete(iocb, ret);
+ WRITE_ONCE(sr->iocb->private, NULL);
+ sr->iocb->ki_complete(sr->iocb, iomap_dio_simple_read_complete(sr));
}
-static void iomap_dio_simple_read_async_done(struct iomap_dio_simple_read *sr)
+static void iomap_dio_simple_read_end_io(struct bio *bio)
{
- struct kiocb *iocb = sr->iocb;
+ struct iomap_dio_simple_read *sr =
+ container_of(bio, struct iomap_dio_simple_read, bio);
if (unlikely(sr->bio.bi_status)) {
- struct inode *inode = file_inode(iocb->ki_filp);
+ struct inode *inode = file_inode(sr->iocb->ki_filp);
INIT_WORK(&sr->work, iomap_dio_simple_read_complete_work);
queue_work(inode->i_sb->s_dio_done_wq, &sr->work);
return;
}
- iomap_dio_simple_read_complete_work(&sr->work);
-}
-
-static void iomap_dio_simple_read_end_io(struct bio *bio)
-{
- struct iomap_dio_simple_read *sr = bio->bi_private;
-
- if (sr->waiter) {
- struct task_struct *waiter = sr->waiter;
-
- WRITE_ONCE(sr->waiter, NULL);
- blk_wake_io_task(waiter);
- return;
- }
-
- if (likely(atomic_read(&sr->state) == IOMAP_DIO_SIMPLE_QUEUED) ||
- atomic_cmpxchg(&sr->state, IOMAP_DIO_SIMPLE_SUBMITTING,
- IOMAP_DIO_SIMPLE_DONE) == IOMAP_DIO_SIMPLE_QUEUED)
- iomap_dio_simple_read_async_done(sr);
+ sr->iocb->ki_complete(sr->iocb, iomap_dio_simple_read_complete(sr));
}
static inline bool iomap_dio_simple_read_supported(struct kiocb *iocb,
@@ -1046,11 +985,13 @@ static inline bool iomap_dio_simple_read_supported(struct kiocb *iocb,
*/
if (count > inode->i_sb->s_blocksize)
return false;
- if (dio_flags & (IOMAP_DIO_FORCE_WAIT | IOMAP_DIO_PARTIAL))
+ if (dio_flags & (IOMAP_DIO_FORCE_WAIT | IOMAP_DIO_PARTIAL |
+ IOMAP_DIO_BOUNCE))
return false;
if (iocb->ki_pos + count > i_size_read(inode))
return false;
+ // XXX: reject fscrypt
return true;
}
@@ -1060,7 +1001,6 @@ static ssize_t iomap_dio_simple_read(struct kiocb *iocb,
{
struct inode *inode = file_inode(iocb->ki_filp);
size_t count = iov_iter_count(iter);
- int nr_pages;
struct iomap_dio_simple_read *sr;
unsigned int alignment;
struct iomap_iter iomi = {
@@ -1074,11 +1014,6 @@ static ssize_t iomap_dio_simple_read(struct kiocb *iocb,
bool wait_for_completion = is_sync_kiocb(iocb);
ssize_t ret;
- if (dio_flags & IOMAP_DIO_BOUNCE)
- nr_pages = bio_iov_bounce_nr_vecs(iter, REQ_OP_READ);
- else
- nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);
-
if (iocb->ki_flags & IOCB_NOWAIT)
iomi.flags |= IOMAP_NOWAIT;
@@ -1120,24 +1055,18 @@ static ssize_t iomap_dio_simple_read(struct kiocb *iocb,
if (user_backed_iter(iter))
dio_flags |= IOMAP_DIO_USER_BACKED;
- bio = bio_alloc_bioset(iomi.iomap.bdev, nr_pages,
- REQ_OP_READ | REQ_SYNC | REQ_IDLE,
- GFP_KERNEL, &iomap_dio_simple_read_pool);
+ bio = bio_alloc_bioset(iomi.iomap.bdev,
+ bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
+ REQ_OP_READ | REQ_SYNC | REQ_IDLE,
+ GFP_KERNEL, &iomap_dio_simple_read_pool);
sr = container_of(bio, struct iomap_dio_simple_read, bio);
-
- fscrypt_set_bio_crypt_ctx(bio, inode, iomi.pos, GFP_KERNEL);
sr->iocb = iocb;
sr->dio_flags = dio_flags;
bio->bi_iter.bi_sector = iomap_sector(&iomi.iomap, iomi.pos);
bio->bi_ioprio = iocb->ki_ioprio;
- bio->bi_private = sr;
- bio->bi_end_io = iomap_dio_simple_read_end_io;
- if (dio_flags & IOMAP_DIO_BOUNCE)
- ret = bio_iov_iter_bounce(bio, iter, count);
- else
- ret = bio_iov_iter_get_pages(bio, iter, alignment - 1);
+ ret = bio_iov_iter_get_pages(bio, iter, alignment - 1);
if (unlikely(ret))
goto out_bio_put;
@@ -1161,49 +1090,22 @@ static ssize_t iomap_dio_simple_read(struct kiocb *iocb,
WRITE_ONCE(iocb->private, bio);
}
- if (wait_for_completion) {
- sr->waiter = current;
- blk_crypto_submit_bio(bio);
- } else {
- atomic_set(&sr->state, IOMAP_DIO_SIMPLE_SUBMITTING);
- sr->waiter = NULL;
- blk_crypto_submit_bio(bio);
- ret = -EIOCBQUEUED;
- }
-
if (ops->iomap_end)
ops->iomap_end(inode, iomi.pos, count, count, iomi.flags,
&iomi.iomap);
- if (wait_for_completion) {
- for (;;) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- if (!READ_ONCE(sr->waiter))
- break;
- blk_io_schedule();
- }
- __set_current_state(TASK_RUNNING);
-
- ret = iomap_dio_simple_read_finish(iocb, bio,
- blk_status_to_errno(bio->bi_status));
- inode_dio_end(inode);
- trace_iomap_dio_complete(iocb, ret < 0 ? ret : 0,
- ret > 0 ? ret : 0);
- } else if (atomic_cmpxchg(&sr->state, IOMAP_DIO_SIMPLE_SUBMITTING,
- IOMAP_DIO_SIMPLE_QUEUED) ==
- IOMAP_DIO_SIMPLE_DONE) {
- ret = iomap_dio_simple_read_complete(iocb, bio);
- } else {
+ if (!wait_for_completion) {
+ bio->bi_end_io = iomap_dio_simple_read_end_io;
+ submit_bio(bio);
trace_iomap_dio_rw_queued(inode, iomi.pos, count);
+ return -EIOCBQUEUED;
}
- return ret;
+ submit_bio_wait(bio);
+ return iomap_dio_simple_read_complete(sr);
out_bio_release_pages:
- if (dio_flags & IOMAP_DIO_BOUNCE)
- bio_iov_iter_unbounce(bio, true, false);
- else
- bio_release_pages(bio, false);
+ bio_release_pages(bio, false);
out_bio_put:
bio_put(bio);
out_iomap_end:
^ permalink raw reply related
* Re: [PATCH RFC v2 17/18] fs: look up the superblock via the device table in user_get_super()
From: Christoph Hellwig @ 2026-06-24 14:07 UTC (permalink / raw)
To: Christian Brauner
Cc: Jan Kara, Christoph Hellwig, Jens Axboe, Alexander Viro,
linux-block, linux-kernel, linux-fsdevel, Carlos Maiolino,
linux-xfs, Chris Mason, David Sterba, linux-btrfs,
Theodore Ts'o, linux-ext4, Gao Xiang, linux-erofs
In-Reply-To: <20260616-work-super-bdev_holder_global-v2-17-7df6b864028e@kernel.org>
On Tue, Jun 16, 2026 at 04:08:33PM +0200, Christian Brauner wrote:
> user_get_super() still finds the superblock for a device number by
> walking the global super_blocks list under sb_lock. Every superblock is
> registered in the device table under its s_dev since sget_fc() inserts
> it there, including superblocks on anonymous devices, so use the table
> instead.
So what is the benefit of this? It's not like any of these are heavily
used fast paths.
^ permalink raw reply
* Re: [PATCH RFC v2 08/18] fs: add dedicated block device open helpers for filesystems
From: Christoph Hellwig @ 2026-06-24 14:06 UTC (permalink / raw)
To: Jan Kara
Cc: Christian Brauner, Christoph Hellwig, Jens Axboe, Alexander Viro,
linux-block, linux-kernel, linux-fsdevel, Carlos Maiolino,
linux-xfs, Chris Mason, David Sterba, linux-btrfs,
Theodore Ts'o, linux-ext4, Gao Xiang, linux-erofs
In-Reply-To: <xlfnmwv2upjia6ozd4z5l5icaewor4a6cgkafnigulndzmt6r7@rhay3h3wablo>
On Mon, Jun 22, 2026 at 06:28:50PM +0200, Jan Kara wrote:
> > +static int fs_bdev_register(struct file *bdev_file, struct super_block *sb)
> > +{
> > + struct super_dev *sb_dev __free(kfree) = NULL;
>
> Frankly I find the use of __free on sb_dev more confusing than helping in
> this function. If you didn't use it, you could remove the somewhat
> confusing retain_and_null_ptr() calls below, remove this initialization and
> just put one kfree() into the error handling branch when super_dev_insert()
> fails...
It is. __free is really annoying for anything but trivial local
scope only variables.
^ permalink raw reply
* Re: [PATCH RFC v2 07/18] fs: maintain a global device-to-superblock table
From: Christoph Hellwig @ 2026-06-24 14:05 UTC (permalink / raw)
To: Christian Brauner
Cc: Jan Kara, Christoph Hellwig, Jens Axboe, Alexander Viro,
linux-block, linux-kernel, linux-fsdevel, Carlos Maiolino,
linux-xfs, Chris Mason, David Sterba, linux-btrfs,
Theodore Ts'o, linux-ext4, Gao Xiang, linux-erofs
In-Reply-To: <20260616-work-super-bdev_holder_global-v2-7-7df6b864028e@kernel.org>
FYI, I still think maintaining a dev_t to sb mapping vs having a holder
register a claim is a major step backwards architecturally. I spent
a lot of effort to get us out of this.
^ permalink raw reply
* Re: [PATCH RFC v2 01/18] xfs: fix the error unwind in xfs_open_devices()
From: Christoph Hellwig @ 2026-06-24 14:05 UTC (permalink / raw)
To: Christian Brauner
Cc: Jan Kara, Christoph Hellwig, Jens Axboe, Alexander Viro,
linux-block, linux-kernel, linux-fsdevel, Carlos Maiolino,
linux-xfs, Chris Mason, David Sterba, linux-btrfs,
Theodore Ts'o, linux-ext4, Gao Xiang, linux-erofs
In-Reply-To: <20260616-work-super-bdev_holder_global-v2-1-7df6b864028e@kernel.org>
On Tue, Jun 16, 2026 at 04:08:17PM +0200, Christian Brauner wrote:
> Since the rt and log block devices are closed in xfs_free_buftarg() the
> buftarg owns the device file. The error unwind does not respect that:
> when the log buftarg allocation fails, out_free_rtdev_targ frees the rt
> buftarg - releasing rtdev_file - and then falls through to
> out_close_rtdev and releases it a second time.
>
> The unwind also leaves mp->m_rtdev_targp and mp->m_ddev_targp pointing
> to the freed buftargs. The failed mount continues into
> deactivate_locked_super() -> xfs_kill_sb() -> xfs_mount_free(), which
> frees them again.
>
> Clear the buftarg pointers once the unwind freed them and clear
> rtdev_file once the rt buftarg owns it, so nothing is released twice.
>
> Reachable when a buftarg allocation fails after the data buftarg was
> set up: an I/O error in sync_blockdev() or an allocation failure in
> xfs_init_buftarg() while mounting with external rt and log devices.
Looks good:
Reviewed-by: Christoph Hellwig <hch@lst.de>
I actually have a major rework of this area pending, but it probably
won't land for 7.2, so we might as well get this local fix in ASAP.
^ permalink raw reply
* [RFC PATCH v3 6/6] ext4/067: LUFID and encryption+casefold+dirdata
From: Artem Blagodarenko @ 2026-06-24 13:49 UTC (permalink / raw)
To: linux-ext4; +Cc: adilger.kernel, Artem Blagodarenko
In-Reply-To: <20260624134957.19209-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Test ext4 LUFID functionality in the complex combination of
encryption, casefold (case-insensitive), and dirdata features.
Verification uses 'debugfs ls -lD' to check for 'fid: or hash:' markers.
Tests also verify that case-insensitive lookups work correctly and that
encrypted file content is preserved after setting LUFID.
This test validates that LUFID works correctly when encryption and
casefold features are enabled, ensuring feature interactions don't
break the LUFID functionality.
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
---
tests/ext4/067 | 137 +++++++++++++++++++++++++++++++++++++++++++++
tests/ext4/067.out | 4 ++
2 files changed, 141 insertions(+)
diff --git a/tests/ext4/067 b/tests/ext4/067
new file mode 100755
index 00000000..acb49c40
--- /dev/null
+++ b/tests/ext4/067
@@ -0,0 +1,137 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2026 The Lustre Collective. All Rights Reserved.
+# Author: Artem Blagodarenko <ablagodarenko@thelustrecollective.com>
+#
+# FS QA Test ext4/067
+#
+# Test ext4 LUFID with encryption and casefold.
+# EXT4_IOC_SET_LUFID is an ioctl that allows LUFID data to be set on a directory entry.
+# directory name hash is stored by EXT4 when casefold and encryption features are enabled.
+
+. ./common/preamble
+_begin_fstest auto quick encrypt casefold
+
+# Import common functions
+. ./common/filter
+. ./common/encrypt
+. ./common/casefold
+. ./common/attr
+. ./common/ext4
+
+_exclude_fs ext2
+_exclude_fs ext3
+
+_require_scratch_nocheck
+_require_scratch_encryption
+_require_scratch_casefold
+_require_command "$SET_LUFID_PROG"
+
+# Check if dirdata feature is supported (required for LUFID IOCTL)
+_require_scratch_dirdata()
+{
+ if test ! -f /sys/fs/ext4/features/dirdata ; then
+ _notrun "dirdata feature not supported by kernel (required for LUFID)"
+ fi
+
+ # Verify that mkfs supports dirdata
+ if ! $MKFS_EXT4_PROG -O dirdata -n $SCRATCH_DEV &>>$seqres.full ; then
+ _notrun "mkfs.ext4 does not support dirdata feature"
+ fi
+
+ # Verify kernel can mount filesystem with encrypt+casefold+dirdata
+ if ! _scratch_mkfs -O encrypt,casefold,dirdata &>>$seqres.full ; then
+ _notrun "failed to create filesystem with encrypt+casefold+dirdata"
+ fi
+ if ! _try_scratch_mount &>>$seqres.full ; then
+ _notrun "kernel cannot mount filesystem with encrypt+casefold+dirdata"
+ fi
+ _scratch_unmount
+}
+
+_require_scratch_dirdata
+
+# Helper to add a v2 encryption key and set policy on a directory
+_setup_encrypted_dir()
+{
+ local dir=$1
+ local raw_key=$(_generate_raw_encryption_key)
+ local keyspec=$(_add_enckey $SCRATCH_MNT "$raw_key" | awk '{print $NF}')
+ _set_encpolicy $dir $keyspec
+ _casefold_set_attr $dir
+ echo $keyspec
+}
+
+# Create a filesystem with encryption, casefold, and dirdata features
+_scratch_mkfs -O encrypt,casefold,dirdata &>>$seqres.full
+_scratch_mount
+
+# Test: Create file in encrypted+casefolded directory and set three 16-byte LUFIDs
+echo "Test: Set three 16-byte LUFIDs on file in encrypted+casefolded directory"
+mkdir $SCRATCH_MNT/encrypted_dir
+_setup_encrypted_dir $SCRATCH_MNT/encrypted_dir > /dev/null
+
+echo "encrypted content" > $SCRATCH_MNT/encrypted_dir/testfile.txt
+
+lufid_payload=$'\xde\xad\xbe\xef\x01\x02\x03\x04\x11\x12\x13\x14\x21\x22\x23\x24\xca\xfe\xba\xbe\x05\x06\x07\x08\x31\x32\x33\x34\x41\x42\x43\x44\xfe\xed\xfa\xce\x09\x0a\x0b\x0c\x51\x52\x53\x54\x61\x62\x63\x64'
+expected_fid='[0xdeadbeef01020304:0x11121314:0x21222324],[0xcafebabe05060708:0x31323334:0x41424344],[0xfeedface090a0b0c:0x51525354:0x61626364]'
+
+# Set three LUFIDs on the file at the same time (48 bytes total: three 16-byte FIDs)
+# First FID: [part1 (8 bytes):part2 (4 bytes):part3 (4 bytes)]
+# Second FID: [part1 (8 bytes):part2 (4 bytes):part3 (4 bytes)]
+# Third FID: [part1 (8 bytes):part2 (4 bytes):part3 (4 bytes)]
+set_lufid $SCRATCH_MNT/encrypted_dir testfile.txt "$lufid_payload" >>$seqres.full 2>&1
+if [ $? -ne 0 ]; then
+ echo "FAIL: Could not set three LUFIDs on encrypted+casefolded file"
+ _scratch_unmount
+ _check_scratch_fs
+ status=1
+ exit
+fi
+
+# Verify file is still accessible
+if [ ! -f $SCRATCH_MNT/encrypted_dir/testfile.txt ]; then
+ echo "FAIL: Encrypted file not accessible after setting LUFID"
+ _scratch_unmount
+ _check_scratch_fs
+ status=1
+ exit
+fi
+
+# Verify file content is preserved
+enc_content=$(cat $SCRATCH_MNT/encrypted_dir/testfile.txt 2>/dev/null)
+if [ "$enc_content" != "encrypted content" ]; then
+ echo "FAIL: Encrypted file content not preserved after setting LUFID"
+ _scratch_unmount
+ _check_scratch_fs
+ status=1
+ exit
+fi
+
+# Test case-insensitive lookup still works with LUFID
+if [ ! -f "$SCRATCH_MNT/encrypted_dir/TESTFILE.TXT" ]; then
+ echo "FAIL: Case-insensitive lookup doesn't work with LUFID"
+ _scratch_unmount
+ _check_scratch_fs
+ status=1
+ exit
+fi
+
+echo "Successfully set and verified three 16-byte LUFIDs on encrypted+casefolded file"
+
+# Dump directory structure to verify dirdata
+if ! _dump_dir_structure $SCRATCH_MNT/encrypted_dir testfile.txt "$expected_fid"; then
+ echo "FAIL: Stored LUFID does not match expected value"
+ _scratch_unmount
+ _check_scratch_fs
+ status=1
+ exit
+fi
+
+# Cleanup and verify filesystem
+_scratch_unmount
+_check_scratch_fs
+
+# success, all done
+status=0
+exit
diff --git a/tests/ext4/067.out b/tests/ext4/067.out
new file mode 100644
index 00000000..1c9a8126
--- /dev/null
+++ b/tests/ext4/067.out
@@ -0,0 +1,4 @@
+QA output created by 067
+Test: Set three 16-byte LUFIDs on file in encrypted+casefolded directory
+Successfully set and verified three 16-byte LUFIDs on encrypted+casefolded file
+ Directory structure of encrypted_dir: OK (dirdata verified)
--
2.43.7
^ permalink raw reply related
* [RFC PATCH v3 5/6] ext4/066: verify LUFID dirdata operations
From: Artem Blagodarenko @ 2026-06-24 13:49 UTC (permalink / raw)
To: linux-ext4; +Cc: adilger.kernel, Artem Blagodarenko
In-Reply-To: <20260624134957.19209-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Test ext4 LUFID set/get operations on dirdata fields. This test
verifies that the EXT4_IOC_SET_LUFID ioctl can be used
to attach LUFID data to a directory entry and that `debugfs ls -lD`
can read this data.
Verification uses `debugfs ls -lD` to check for `fid:` markers,
indicating the presence of LUFID data in directory entries.
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
---
tests/ext4/066 | 158 +++++++++++++++++++++++++++++++++++++++++++++
tests/ext4/066.out | 4 ++
2 files changed, 162 insertions(+)
diff --git a/tests/ext4/066 b/tests/ext4/066
new file mode 100755
index 00000000..ae98fb45
--- /dev/null
+++ b/tests/ext4/066
@@ -0,0 +1,158 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2026 The Lustre Collective. All Rights Reserved.
+# Author: Artem Blagodarenko <ablagodarenko@thelustrecollective.com>
+#
+# FS QA Test ext4/066
+#
+# Test the ext4 dirdata feature with LUFID ioctl functionality.
+# LUFID is a 16-byte identifier that can be attached
+# to directory entries. It is used for quick access to file metadata.
+# EXT4_IOC_SET_LUFID is an ioctl that allows LUFID data to be set on a
+# directory entry.
+
+. ./common/preamble
+_begin_fstest auto quick
+
+# Import common functions
+. ./common/filter
+. ./common/ext4
+
+_exclude_fs ext2
+_exclude_fs ext3
+
+_require_scratch_nocheck
+_require_command "$SET_LUFID_PROG"
+
+# Check if dirdata feature is supported (required for LUFID IOCTL)
+_require_scratch_dirdata()
+{
+ if test ! -f /sys/fs/ext4/features/dirdata ; then
+ _notrun "dirdata feature not supported by kernel (required for LUFID)"
+ fi
+
+ # Verify that mkfs supports dirdata
+ if ! $MKFS_EXT4_PROG -O dirdata -n $SCRATCH_DEV &>>$seqres.full ; then
+ _notrun "mkfs.ext4 does not support dirdata feature"
+ fi
+
+ # Verify kernel can mount filesystem with dirdata
+ if ! _scratch_mkfs -O dirdata &>>$seqres.full ; then
+ _notrun "failed to create filesystem with dirdata"
+ fi
+ if ! _try_scratch_mount &>>$seqres.full ; then
+ _notrun "kernel cannot mount filesystem with dirdata"
+ fi
+ _scratch_unmount
+}
+
+_require_scratch_dirdata
+
+_u32_to_le_hex()
+{
+ local v=$1
+ local h
+
+ h=$(printf '%08x' "$((v & 0xffffffff))")
+ printf '%s%s%s%s' "${h:6:2}" "${h:4:2}" "${h:2:2}" "${h:0:2}"
+}
+
+_build_default_expected_fid()
+{
+ local path=$1
+ local inode
+ local version
+ local ino_hi ino_lo
+ local ver_hi ver_lo
+ local seq_hex oid_hex ver_hex
+
+ inode=$(stat -c '%i' "$path") || return 1
+ version=$(debugfs -R "stat <${inode}>" $SCRATCH_DEV 2>/dev/null | \
+ sed -n 's/.*Generation:[[:space:]]*\([0-9xa-fA-F]\+\).*/\1/p' | head -n 1)
+
+ if [ -z "$version" ]; then
+ return 1
+ fi
+
+ ino_hi=$(((inode >> 32) & 0xffffffff))
+ ino_lo=$((inode & 0xffffffff))
+ ver_lo=$((version & 0xffffffff))
+ ver_hi=$(((version >> 32) & 0xffffffff))
+
+ # Match lu_fid cast semantics: set_lufid stores u32 words in native memory
+ # order; debugfs reads lu_fid fields and prints f_seq/f_oid/f_ver.
+ seq_hex="$(_u32_to_le_hex "$ino_hi")$(_u32_to_le_hex "$ino_lo")"
+ oid_hex="$(_u32_to_le_hex "$ver_lo")"
+ ver_hex="$(_u32_to_le_hex "$ver_hi")"
+
+ printf '[0x%x:0x%x:0x%x]' "$((16#$seq_hex))" "$((16#$oid_hex))" \
+ "$((16#$ver_hex))"
+}
+
+# Create a filesystem with dirdata feature
+_scratch_mkfs -O dirdata &>>$seqres.full
+_scratch_mount
+
+# Test: Create file and set multiple 16-byte LUFIDs on the same file
+echo "Test: Set multiple 16-byte LUFIDs on the same file"
+mkdir -p $SCRATCH_MNT/lufid_test
+echo "test content" > $SCRATCH_MNT/lufid_test/testfile.txt
+
+# Set both LUFIDs on the file at the same time (32 bytes total: two 16-byte FIDs)
+# First FID: [part1 (8 bytes):part2 (4 bytes):part3 (4 bytes)]
+# Second FID: [part1 (8 bytes):part2 (4 bytes):part3 (4 bytes)]
+set_lufid $SCRATCH_MNT/lufid_test testfile.txt >>$seqres.full
+if [ $? -ne 0 ]; then
+ echo "FAIL: Could not set both LUFIDs on testfile.txt"
+ _scratch_unmount
+ _check_scratch_fs
+ status=1
+ exit
+fi
+
+# Verify file is still accessible
+if [ ! -f $SCRATCH_MNT/lufid_test/testfile.txt ]; then
+ echo "FAIL: File not accessible after setting LUFIDs"
+ _scratch_unmount
+ _check_scratch_fs
+ status=1
+ exit
+fi
+
+# Verify file content is preserved
+content=$(cat $SCRATCH_MNT/lufid_test/testfile.txt 2>/dev/null)
+if [ "$content" != "test content" ]; then
+ echo "FAIL: File content not preserved after setting LUFIDs"
+ _scratch_unmount
+ _check_scratch_fs
+ status=1
+ exit
+fi
+
+expected_fid=$(_build_default_expected_fid $SCRATCH_MNT/lufid_test/testfile.txt)
+if [ -z "$expected_fid" ]; then
+ echo "FAIL: Could not calculate expected default LUFID"
+ _scratch_unmount
+ _check_scratch_fs
+ status=1
+ exit
+fi
+
+echo "Successfully set and verified both 16-byte LUFIDs on same file at the same time"
+
+# Dump directory structure to verify dirdata
+if ! _dump_dir_structure $SCRATCH_MNT/lufid_test testfile.txt "$expected_fid"; then
+ echo "FAIL: Stored LUFID does not match expected default value"
+ _scratch_unmount
+ _check_scratch_fs
+ status=1
+ exit
+fi
+
+# Cleanup and verify filesystem
+_scratch_unmount
+_check_scratch_fs
+
+# success, all done
+status=0
+exit
diff --git a/tests/ext4/066.out b/tests/ext4/066.out
new file mode 100644
index 00000000..4ec0fd6d
--- /dev/null
+++ b/tests/ext4/066.out
@@ -0,0 +1,4 @@
+QA output created by 066
+Test: Set multiple 16-byte LUFIDs on the same file
+Successfully set and verified both 16-byte LUFIDs on same file at the same time
+ Directory structure of lufid_test: OK (dirdata verified)
--
2.43.7
^ permalink raw reply related
* [RFC PATCH v3 4/6] ext4: add set_lufid utility
From: Artem Blagodarenko @ 2026-06-24 13:49 UTC (permalink / raw)
To: linux-ext4; +Cc: adilger.kernel, Artem Blagodarenko
In-Reply-To: <20260624134957.19209-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
EXT4 provides the EXT4_IOC_SET_LUFID ioctl, which allows setting
or replacing the LUFID dirdata field for an existing directory entry.
The set_lufid utility uses this ioctl and accepts a directory path,
directory entry name, and LUFID value as arguments.
This utility is used by subsequent dirdata-related tests.
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
---
common/config | 1 +
src/Makefile | 2 +-
src/set_lufid.c | 196 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 198 insertions(+), 1 deletion(-)
diff --git a/common/config b/common/config
index d5299d5b..a19e1d7e 100644
--- a/common/config
+++ b/common/config
@@ -210,6 +210,7 @@ export LVM_PROG="$(type -P lvm)"
export LSATTR_PROG="$(type -P lsattr)"
export CHATTR_PROG="$(type -P chattr)"
export DEBUGFS_PROG="$(type -P debugfs)"
+export SET_LUFID_PROG="$(type -P set_lufid || echo $here/src/set_lufid)"
export UUIDGEN_PROG="$(type -P uuidgen)"
export KEYCTL_PROG="$(type -P keyctl)"
export XZ_PROG="$(type -P xz)"
diff --git a/src/Makefile b/src/Makefile
index 31ac43b2..a1f161b0 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -36,7 +36,7 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
fscrypt-crypt-util bulkstat_null_ocount splice-test chprojid_fail \
detached_mounts_propagation ext4_resize t_readdir_3 splice2pipe \
uuid_ioctl t_snapshot_deleted_subvolume fiemap-fault min_dio_alignment \
- rw_hint fs-monitor
+ rw_hint fs-monitor set_lufid
EXTRA_EXECS = dmerror fill2attr fill2fs fill2fs_check scaleread.sh \
btrfs_crc32c_forged_name.py popdir.pl popattr.py \
diff --git a/src/set_lufid.c b/src/set_lufid.c
new file mode 100644
index 00000000..92af6c6d
--- /dev/null
+++ b/src/set_lufid.c
@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * set_lufid.c --- Set LUFID on a directory entry using IOCTL
+ *
+ * Copyright (C) 2026 The Lustre Collective. All Rights Reserved.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <libgen.h>
+#include <stdint.h>
+#include <linux/fs.h>
+
+/* Structure for EXT4_IOC_SET_LUFID - should match kernel definition */
+struct ext4_dirdata_fid {
+ __u8 edf_data_len;
+ char edf_data[255];
+} __attribute__((packed));
+
+struct ext4_set_lufid {
+ __u8 esl_name_len;
+ char esl_name[255 + 1];
+ union {
+ char esl_data[1 + 255];
+ struct ext4_dirdata_fid esl_edf;
+ };
+} __attribute__((packed));
+
+#ifndef EXT4_IOC_SET_LUFID
+#define EXT4_IOC_SET_LUFID _IOW('f', 47, struct ext4_set_lufid)
+#endif
+
+static void usage(const char *prog)
+{
+ fprintf(stderr, "Usage: %s DIRECTORY FILENAME [LUFID]\n", prog);
+ fprintf(stderr, " DIRECTORY: path to the directory containing the FILENAME\n");
+ fprintf(stderr, " FILENAME: name of the file to set LUFID on\n");
+ fprintf(stderr, " LUFID: data to attach (generated if not passed)\n");
+ exit(1);
+}
+
+static void dump_lufid_payload(const char *data, int len)
+{
+ int i;
+
+ printf("LUFID payload length: %d bytes\n", len);
+ printf("LUFID payload hex:");
+ for (i = 0; i < len; i++)
+ printf(" %02x", (unsigned char)data[i]);
+ printf("\n");
+}
+
+static int build_default_lufid(int dir_fd, const char *dir_path, const char *filename,
+ uint32_t fid[5])
+{
+ int file_fd;
+ unsigned long ver = 0;
+ struct stat st;
+
+ /* Build an IGIF-style default payload from inode + version. */
+ file_fd = openat(dir_fd, filename, O_RDONLY | O_CLOEXEC);
+ if (file_fd < 0) {
+ fprintf(stderr, "Error opening %s/%s: %s\n",
+ dir_path, filename, strerror(errno));
+ return -1;
+ }
+
+ if (fstat(file_fd, &st) < 0) {
+ fprintf(stderr, "Error stating %s/%s: %s\n",
+ dir_path, filename, strerror(errno));
+ close(file_fd);
+ return -1;
+ }
+
+ fid[0] = (uint32_t)(st.st_ino >> 32);
+ fid[1] = (uint32_t)st.st_ino;
+
+ if (ioctl(file_fd, FS_IOC_GETVERSION, &ver) < 0) {
+ fprintf(stderr, "Error calling EXT4_IOC_GETVERSION for %s/%s: %s\n",
+ dir_path, filename, strerror(errno));
+ close(file_fd);
+ return -1;
+ }
+
+ fid[2] = (uint32_t)ver;
+ fid[3] = (uint32_t)(ver >> 32);
+
+ close(file_fd);
+ return 0;
+}
+
+int main(int argc, char *argv[])
+{
+ const char *dir_path;
+ const char *filename;
+ const char *lufid_data;
+ DIR *dirp;
+ int fd;
+ int name_len, data_len;
+ struct ext4_set_lufid lufid_args;
+ struct stat st;
+ uint32_t fid[4];
+ int rc;
+
+ if (argc < 2) {
+ usage(argv[0]);
+ }
+
+ dir_path = argv[1];
+ filename = argv[2];
+ name_len = strlen(filename) + 1; /* +1 for NUL terminator */
+
+ if (name_len == 0 || name_len > 255) {
+ fprintf(stderr, "Error: Invalid filename length: %d (must be 1-256 with NUL)\n",
+ name_len);
+ return 1;
+ }
+
+ /* Check if directory exists and is a directory */
+ if (stat(dir_path, &st) < 0) {
+ fprintf(stderr, "Error accessing %s: %s\n", dir_path, strerror(errno));
+ return 1;
+ }
+
+ if (!S_ISDIR(st.st_mode)) {
+ fprintf(stderr, "Error: %s is not a directory\n", dir_path);
+ return 1;
+ }
+
+ /* Open the directory */
+ dirp = opendir(dir_path);
+ if (!dirp) {
+ fprintf(stderr, "Error opening directory %s: %s\n", dir_path, strerror(errno));
+ return 1;
+ }
+
+ fd = dirfd(dirp);
+ if (fd < 0) {
+ fprintf(stderr, "Error getting directory fd: %s\n", strerror(errno));
+ closedir(dirp);
+ return 1;
+ }
+
+ if (argc > 3) {
+ lufid_data = argv[3];
+ data_len = strlen(lufid_data);
+ } else {
+ rc = build_default_lufid(fd, dir_path, filename, fid);
+ if (rc) {
+ fprintf(stderr, "Error getting lufid for %s/%s\n",
+ dir_path, filename);
+ closedir(dirp);
+ return 1;
+ }
+ lufid_data = (char *)fid;
+ data_len = sizeof(fid);
+ }
+
+ if (data_len == 0 || data_len > 255) {
+ fprintf(stderr, "Error: Invalid LUFID data length: %d (must be 1-255)\n",
+ data_len);
+ closedir(dirp);
+ return 1;
+ }
+
+ /* Prepare LUFID data */
+ memset(&lufid_args, 0, sizeof(lufid_args));
+ lufid_args.esl_name_len = name_len;
+ lufid_args.esl_edf.edf_data_len = data_len;
+ /* Ensure filename is properly NUL-terminated at the correct position */
+ strncpy(lufid_args.esl_name, filename, name_len - 1);
+ lufid_args.esl_name[name_len - 1] = '\0';
+ memcpy(lufid_args.esl_edf.edf_data, lufid_data, data_len);
+
+ /* Call the ioctl */
+ if (ioctl(fd, EXT4_IOC_SET_LUFID, &lufid_args)) {
+ fprintf(stderr, "Error calling EXT4_IOC_SET_LUFID for %s/%s: %s\n",
+ dir_path, filename, strerror(errno));
+ closedir(dirp);
+ return 1;
+ }
+
+ closedir(dirp);
+ printf("Successfully set LUFID on %s in directory %s\n", filename, dir_path);
+ dump_lufid_payload(lufid_args.esl_edf.edf_data, data_len);
+
+ return 0;
+}
--
2.43.7
^ permalink raw reply related
* [RFC PATCH v3 3/6] ext4/065 encryption + casefold + dirdata feature combination
From: Artem Blagodarenko @ 2026-06-24 13:49 UTC (permalink / raw)
To: linux-ext4; +Cc: adilger.kernel, Artem Blagodarenko
In-Reply-To: <20260624134957.19209-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Test ext4 encryption + casefold + dirdata feature combination.
This test verifies that files created in directories with encryption,
case-insensitive (casefold), and dirdata attributes work correctly.
See ext4/064 for the same test WITHOUT dirdata feature.
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
---
tests/ext4/065 | 217 +++++++++++++++++++++++++++++++++++++++++++++
tests/ext4/065.out | 26 ++++++
2 files changed, 243 insertions(+)
diff --git a/tests/ext4/065 b/tests/ext4/065
new file mode 100755
index 00000000..0ad7a382
--- /dev/null
+++ b/tests/ext4/065
@@ -0,0 +1,217 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2026 The Lustre Collective. All Rights Reserved.
+# Author: Artem Blagodarenko <ablagodarenko@thelustrecollective.com>
+#
+# FS QA Test ext4/065
+#
+# Test ext4 encryption + casefold + dirdata feature combination.
+# This test verifies that files created in directories with encryption,
+# case-insensitive (casefold), and dirdata attributes work correctly.
+# See ext4/064 for the same test WITHOUT dirdata feature.
+#
+. ./common/preamble
+_begin_fstest auto quick encrypt casefold
+
+# get standard environment and checks
+. ./common/filter
+. ./common/encrypt
+. ./common/casefold
+. ./common/attr
+. ./common/ext4
+
+_exclude_fs ext2
+_exclude_fs ext3
+
+# Check if dirdata feature is supported and can be used with encrypt+casefold
+_require_scratch_dirdata()
+{
+ if test ! -f /sys/fs/ext4/features/dirdata ; then
+ _notrun "dirdata feature not supported by kernel"
+ fi
+
+ # Debug: log e2fsprogs tool paths and versions
+ echo "=== _require_scratch_dirdata debug info ===" >> $seqres.full
+ echo "E2FSCK_PROG: $E2FSCK_PROG" >> $seqres.full
+ echo "E2FSCK_PROG resolved: $(type -P e2fsck)" >> $seqres.full
+ echo "MKFS_EXT4_PROG: $MKFS_EXT4_PROG" >> $seqres.full
+ echo "fsck -t ext4 resolves to: $(type -P fsck.ext4)" >> $seqres.full
+ $E2FSCK_PROG -V >> $seqres.full 2>&1
+ $MKFS_EXT4_PROG -V >> $seqres.full 2>&1
+ echo "=== end debug info ===" >> $seqres.full
+
+ # Also verify that mkfs supports dirdata
+ if ! $MKFS_EXT4_PROG -O dirdata -n $SCRATCH_DEV &>>$seqres.full ; then
+ _notrun "mkfs.ext4 does not support dirdata feature"
+ fi
+
+ # Verify kernel can mount filesystem with encrypt+casefold+dirdata
+ echo "Running: _scratch_mkfs -O encrypt,casefold,dirdata" >> $seqres.full
+ if ! _scratch_mkfs -O encrypt,casefold,dirdata &>>$seqres.full ; then
+ _notrun "failed to create filesystem with encrypt+casefold+dirdata"
+ fi
+ if ! _try_scratch_mount &>>$seqres.full ; then
+ _notrun "kernel cannot mount filesystem with encrypt+casefold+dirdata"
+ fi
+ _scratch_unmount
+}
+
+_require_scratch_nocheck
+_require_scratch_encryption
+_require_scratch_casefold
+_require_scratch_dirdata
+_require_xfs_io_command "set_encpolicy"
+_require_xfs_io_command "add_enckey"
+
+# Helper to add a v2 encryption key and set policy on a directory
+_setup_encrypted_casefold_dir()
+{
+ local dir=$1
+ local raw_key=$(_generate_raw_encryption_key)
+ local keyspec=$(_add_enckey $SCRATCH_MNT "$raw_key" | awk '{print $NF}')
+ _set_encpolicy $dir $keyspec
+ _casefold_set_attr $dir
+ echo $keyspec
+}
+
+# Create a filesystem with encrypt, casefold, and dirdata features
+# Debug: log e2fsprogs tool paths and versions
+echo "=== e2fsprogs debug info ===" >> $seqres.full
+echo "E2FSCK_PROG: $E2FSCK_PROG" >> $seqres.full
+echo "E2FSCK_PROG resolved: $(type -P e2fsck)" >> $seqres.full
+echo "MKFS_EXT4_PROG: $MKFS_EXT4_PROG" >> $seqres.full
+echo "FSCK_OPTIONS: $FSCK_OPTIONS" >> $seqres.full
+echo "fsck -t ext4 resolves to: $(type -P fsck.ext4)" >> $seqres.full
+$E2FSCK_PROG -V >> $seqres.full 2>&1
+$MKFS_EXT4_PROG -V >> $seqres.full 2>&1
+echo "=== end e2fsprogs debug info ===" >> $seqres.full
+
+_scratch_mkfs -O encrypt,casefold,dirdata &>>$seqres.full
+_scratch_mount
+
+# Test 1: Create an encrypted + casefolded directory and verify lookups work
+echo "Test 1: Basic encrypted casefold lookup with dirdata"
+mkdir $SCRATCH_MNT/test1
+_setup_encrypted_casefold_dir $SCRATCH_MNT/test1 > /dev/null
+
+# Create file with lowercase, lookup with uppercase
+echo "hello" > $SCRATCH_MNT/test1/testfile.txt
+if [ -f "$SCRATCH_MNT/test1/TESTFILE.TXT" ]; then
+ echo "Case-insensitive lookup works in encrypted dir"
+else
+ echo "FAIL: Case-insensitive lookup failed in encrypted dir"
+fi
+
+# Verify the exact name on disk is preserved
+if _casefold_check_exact_name "$SCRATCH_MNT/test1" "testfile.txt"; then
+ echo "Original filename preserved"
+else
+ echo "FAIL: Original filename not preserved"
+fi
+_dump_dir_structure $SCRATCH_MNT/test1
+
+# Test 2: Create files with different case variations
+echo "Test 2: Conflicting names in encrypted casefold dir"
+mkdir $SCRATCH_MNT/test2
+_setup_encrypted_casefold_dir $SCRATCH_MNT/test2 > /dev/null
+
+echo "first" > $SCRATCH_MNT/test2/MyFile.txt
+# This should fail or overwrite since "MYFILE.TXT" is equivalent
+echo "second" > $SCRATCH_MNT/test2/MYFILE.TXT 2>/dev/null
+content=$(cat $SCRATCH_MNT/test2/myfile.txt)
+echo "Content after writes: $content"
+_dump_dir_structure $SCRATCH_MNT/test2
+
+# Test 3: Unicode normalization in encrypted casefold dir
+echo "Test 3: Unicode in encrypted casefold dir"
+mkdir $SCRATCH_MNT/test3
+_setup_encrypted_casefold_dir $SCRATCH_MNT/test3 > /dev/null
+
+# Test with UTF-8 characters
+fr_file1=$(echo -e "cafe\xcc\x81.txt")
+fr_file2=$(echo -e "caf\xc3\xa9.txt")
+echo "french" > "$SCRATCH_MNT/test3/$fr_file1"
+if [ -f "$SCRATCH_MNT/test3/$fr_file2" ]; then
+ echo "Unicode normalization works in encrypted dir"
+else
+ echo "FAIL: Unicode normalization failed in encrypted dir"
+fi
+_dump_dir_structure $SCRATCH_MNT/test3
+
+# Test 4: Directory operations in encrypted casefold dir
+echo "Test 4: Directory operations in encrypted casefold dir"
+mkdir $SCRATCH_MNT/test4
+_setup_encrypted_casefold_dir $SCRATCH_MNT/test4 > /dev/null
+
+mkdir $SCRATCH_MNT/test4/SubDir
+if [ -d "$SCRATCH_MNT/test4/SUBDIR" ]; then
+ echo "Directory case-insensitive lookup works"
+else
+ echo "FAIL: Directory case-insensitive lookup failed"
+fi
+_dump_dir_structure $SCRATCH_MNT/test4
+
+# Test 5: Verify inheritance of casefold+encryption in subdirectories
+echo "Test 5: Inheritance of attributes"
+mkdir $SCRATCH_MNT/test5
+_setup_encrypted_casefold_dir $SCRATCH_MNT/test5 > /dev/null
+
+mkdir $SCRATCH_MNT/test5/child
+echo "data" > $SCRATCH_MNT/test5/child/file.txt
+if [ -f "$SCRATCH_MNT/test5/CHILD/FILE.TXT" ]; then
+ echo "Attributes inherited correctly"
+else
+ echo "FAIL: Attributes not inherited"
+fi
+_dump_dir_structure $SCRATCH_MNT/test5
+
+# Test 6: Remove and recreate with different case
+echo "Test 6: Remove and recreate with different case"
+mkdir $SCRATCH_MNT/test6
+_setup_encrypted_casefold_dir $SCRATCH_MNT/test6 > /dev/null
+
+echo "original" > $SCRATCH_MNT/test6/RemoveMe.txt
+rm $SCRATCH_MNT/test6/REMOVEME.TXT
+echo "recreated" > $SCRATCH_MNT/test6/REMOVEME.TXT
+if _casefold_check_exact_name "$SCRATCH_MNT/test6" "REMOVEME.TXT"; then
+ echo "Recreated file has new case"
+else
+ echo "FAIL: Recreated file case incorrect"
+fi
+_dump_dir_structure $SCRATCH_MNT/test6
+
+# Test 7: Hard links in encrypted casefold dir
+echo "Test 7: Hard links in encrypted casefold dir"
+mkdir $SCRATCH_MNT/test7
+_setup_encrypted_casefold_dir $SCRATCH_MNT/test7 > /dev/null
+
+echo "linkdata" > $SCRATCH_MNT/test7/original.txt
+ln $SCRATCH_MNT/test7/original.txt $SCRATCH_MNT/test7/hardlink.txt
+if [ -f "$SCRATCH_MNT/test7/HARDLINK.TXT" ]; then
+ echo "Hard link case-insensitive lookup works"
+else
+ echo "FAIL: Hard link case-insensitive lookup failed"
+fi
+_dump_dir_structure $SCRATCH_MNT/test7
+
+# Cleanup and verify filesystem
+_scratch_unmount
+
+# Dirdata analysis summary
+echo ""
+echo "Dirdata analysis:"
+echo "=== e2fsprogs debug info (before _check_scratch_fs) ===" >> $seqres.full
+echo "E2FSCK_PROG: $E2FSCK_PROG" >> $seqres.full
+echo "E2FSCK_PROG resolved: $(type -P e2fsck)" >> $seqres.full
+echo "fsck -t ext4 resolves to: $(type -P fsck.ext4)" >> $seqres.full
+echo "FSCK_OPTIONS: $FSCK_OPTIONS" >> $seqres.full
+$E2FSCK_PROG -V >> $seqres.full 2>&1
+echo "=== end e2fsprogs debug info ===" >> $seqres.full
+
+_check_scratch_fs
+
+echo "Encrypted casefold tests with dirdata completed"
+
+# success, all done
+status=0
+exit
diff --git a/tests/ext4/065.out b/tests/ext4/065.out
new file mode 100644
index 00000000..c1316430
--- /dev/null
+++ b/tests/ext4/065.out
@@ -0,0 +1,26 @@
+QA output created by 065
+Test 1: Basic encrypted casefold lookup with dirdata
+Case-insensitive lookup works in encrypted dir
+Original filename preserved
+ Directory structure of test1: OK (dirdata verified)
+Test 2: Conflicting names in encrypted casefold dir
+Content after writes: second
+ Directory structure of test2: OK (dirdata verified)
+Test 3: Unicode in encrypted casefold dir
+Unicode normalization works in encrypted dir
+ Directory structure of test3: OK (dirdata verified)
+Test 4: Directory operations in encrypted casefold dir
+Directory case-insensitive lookup works
+ Directory structure of test4: OK (dirdata verified)
+Test 5: Inheritance of attributes
+Attributes inherited correctly
+ Directory structure of test5: OK (dirdata verified)
+Test 6: Remove and recreate with different case
+Recreated file has new case
+ Directory structure of test6: OK (dirdata verified)
+Test 7: Hard links in encrypted casefold dir
+Hard link case-insensitive lookup works
+ Directory structure of test7: OK (dirdata verified)
+
+Dirdata analysis:
+Encrypted casefold tests with dirdata completed
--
2.43.7
^ permalink raw reply related
* [RFC PATCH v3 2/6] ext4/064 encryption + casefold feature combination WITHOUT dirdata
From: Artem Blagodarenko @ 2026-06-24 13:49 UTC (permalink / raw)
To: linux-ext4; +Cc: adilger.kernel, Artem Blagodarenko
In-Reply-To: <20260624134957.19209-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
This test verifies that files created in directories with both
encryption and case-insensitive (casefold) attributes work correctly.
See ext4/065 for the same test WITH dirdata feature enabled.
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
---
tests/ext4/064 | 153 +++++++++++++++++++++++++++++++++++++++++++++
tests/ext4/064.out | 17 +++++
2 files changed, 170 insertions(+)
diff --git a/tests/ext4/064 b/tests/ext4/064
new file mode 100755
index 00000000..53450927
--- /dev/null
+++ b/tests/ext4/064
@@ -0,0 +1,153 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (c) 2026 The Lustre Collective. All Rights Reserved.
+# Author: Artem Blagodarenko <ablagodarenko@thelustrecollective.com>
+#
+# FS QA Test ext4/064
+#
+# Test ext4 encryption + casefold feature combination WITHOUT dirdata.
+# This test verifies that files created in directories with both
+# encryption and case-insensitive (casefold) attributes work correctly.
+# See ext4/065 for the same test WITH dirdata feature enabled.
+#
+. ./common/preamble
+_begin_fstest auto quick encrypt casefold
+
+# get standard environment and checks
+. ./common/filter
+. ./common/encrypt
+. ./common/casefold
+. ./common/attr
+
+_exclude_fs ext2
+_exclude_fs ext3
+
+_require_scratch_nocheck
+_require_scratch_encryption
+_require_scratch_casefold
+_require_xfs_io_command "set_encpolicy"
+_require_xfs_io_command "add_enckey"
+
+# Helper to add a v2 encryption key and set policy on a directory
+_setup_encrypted_casefold_dir()
+{
+ local dir=$1
+ local raw_key=$(_generate_raw_encryption_key)
+ local keyspec=$(_add_enckey $SCRATCH_MNT "$raw_key" | awk '{print $NF}')
+ _set_encpolicy $dir $keyspec
+ _casefold_set_attr $dir
+ echo $keyspec
+}
+
+# Create a filesystem with both encrypt and casefold features
+_scratch_mkfs -O encrypt,casefold &>>$seqres.full
+_scratch_mount
+
+# Test 1: Create an encrypted + casefolded directory and verify lookups work
+echo "Test 1: Basic encrypted casefold lookup"
+mkdir $SCRATCH_MNT/test1
+_setup_encrypted_casefold_dir $SCRATCH_MNT/test1 > /dev/null
+
+# Create file with lowercase, lookup with uppercase
+echo "hello" > $SCRATCH_MNT/test1/testfile.txt
+if [ -f "$SCRATCH_MNT/test1/TESTFILE.TXT" ]; then
+ echo "Case-insensitive lookup works in encrypted dir"
+else
+ echo "FAIL: Case-insensitive lookup failed in encrypted dir"
+fi
+
+# Verify the exact name on disk is preserved
+if _casefold_check_exact_name "$SCRATCH_MNT/test1" "testfile.txt"; then
+ echo "Original filename preserved"
+else
+ echo "FAIL: Original filename not preserved"
+fi
+
+# Test 2: Create files with different case variations
+echo "Test 2: Conflicting names in encrypted casefold dir"
+mkdir $SCRATCH_MNT/test2
+_setup_encrypted_casefold_dir $SCRATCH_MNT/test2 > /dev/null
+
+echo "first" > $SCRATCH_MNT/test2/MyFile.txt
+# This should fail or overwrite since "MYFILE.TXT" is equivalent
+echo "second" > $SCRATCH_MNT/test2/MYFILE.TXT 2>/dev/null
+content=$(cat $SCRATCH_MNT/test2/myfile.txt)
+echo "Content after writes: $content"
+
+# Test 3: Unicode normalization in encrypted casefold dir
+echo "Test 3: Unicode in encrypted casefold dir"
+mkdir $SCRATCH_MNT/test3
+_setup_encrypted_casefold_dir $SCRATCH_MNT/test3 > /dev/null
+
+# Test with UTF-8 characters
+fr_file1=$(echo -e "cafe\xcc\x81.txt")
+fr_file2=$(echo -e "caf\xc3\xa9.txt")
+echo "french" > "$SCRATCH_MNT/test3/$fr_file1"
+if [ -f "$SCRATCH_MNT/test3/$fr_file2" ]; then
+ echo "Unicode normalization works in encrypted dir"
+else
+ echo "FAIL: Unicode normalization failed in encrypted dir"
+fi
+
+# Test 4: Directory operations in encrypted casefold dir
+echo "Test 4: Directory operations in encrypted casefold dir"
+mkdir $SCRATCH_MNT/test4
+_setup_encrypted_casefold_dir $SCRATCH_MNT/test4 > /dev/null
+
+mkdir $SCRATCH_MNT/test4/SubDir
+if [ -d "$SCRATCH_MNT/test4/SUBDIR" ]; then
+ echo "Directory case-insensitive lookup works"
+else
+ echo "FAIL: Directory case-insensitive lookup failed"
+fi
+
+# Test 5: Verify inheritance of casefold+encryption in subdirectories
+echo "Test 5: Inheritance of attributes"
+mkdir $SCRATCH_MNT/test5
+_setup_encrypted_casefold_dir $SCRATCH_MNT/test5 > /dev/null
+
+mkdir $SCRATCH_MNT/test5/child
+echo "data" > $SCRATCH_MNT/test5/child/file.txt
+if [ -f "$SCRATCH_MNT/test5/CHILD/FILE.TXT" ]; then
+ echo "Attributes inherited correctly"
+else
+ echo "FAIL: Attributes not inherited"
+fi
+
+# Test 6: Remove and recreate with different case
+echo "Test 6: Remove and recreate with different case"
+mkdir $SCRATCH_MNT/test6
+_setup_encrypted_casefold_dir $SCRATCH_MNT/test6 > /dev/null
+
+echo "original" > $SCRATCH_MNT/test6/RemoveMe.txt
+rm $SCRATCH_MNT/test6/REMOVEME.TXT
+echo "recreated" > $SCRATCH_MNT/test6/REMOVEME.TXT
+if _casefold_check_exact_name "$SCRATCH_MNT/test6" "REMOVEME.TXT"; then
+ echo "Recreated file has new case"
+else
+ echo "FAIL: Recreated file case incorrect"
+fi
+
+# Test 7: Hard links in encrypted casefold dir
+echo "Test 7: Hard links in encrypted casefold dir"
+mkdir $SCRATCH_MNT/test7
+_setup_encrypted_casefold_dir $SCRATCH_MNT/test7 > /dev/null
+
+echo "linkdata" > $SCRATCH_MNT/test7/original.txt
+ln $SCRATCH_MNT/test7/original.txt $SCRATCH_MNT/test7/hardlink.txt
+if [ -f "$SCRATCH_MNT/test7/HARDLINK.TXT" ]; then
+ echo "Hard link case-insensitive lookup works"
+else
+ echo "FAIL: Hard link case-insensitive lookup failed"
+fi
+
+# Cleanup and verify filesystem
+_scratch_unmount
+_check_scratch_fs
+
+echo "Encrypted casefold tests completed"
+
+# success, all done
+status=0
+exit
diff --git a/tests/ext4/064.out b/tests/ext4/064.out
new file mode 100644
index 00000000..0197e51e
--- /dev/null
+++ b/tests/ext4/064.out
@@ -0,0 +1,17 @@
+QA output created by 064
+Test 1: Basic encrypted casefold lookup
+Case-insensitive lookup works in encrypted dir
+Original filename preserved
+Test 2: Conflicting names in encrypted casefold dir
+Content after writes: second
+Test 3: Unicode in encrypted casefold dir
+Unicode normalization works in encrypted dir
+Test 4: Directory operations in encrypted casefold dir
+Directory case-insensitive lookup works
+Test 5: Inheritance of attributes
+Attributes inherited correctly
+Test 6: Remove and recreate with different case
+Recreated file has new case
+Test 7: Hard links in encrypted casefold dir
+Hard link case-insensitive lookup works
+Encrypted casefold tests completed
--
2.43.7
^ permalink raw reply related
* [RFC PATCH v3 1/6] ext4: add common helper to check whether dirdata is applied
From: Artem Blagodarenko @ 2026-06-24 13:49 UTC (permalink / raw)
To: linux-ext4; +Cc: adilger.kernel, Artem Blagodarenko
In-Reply-To: <20260624134957.19209-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Add a helper that lists a directory with the -lD flags and checks
whether any dirdata fields exist.
This helper will be used by subsequent dirdata-related patches.
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
---
common/ext4 | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/common/ext4 b/common/ext4
index a2ce456d..47c31db9 100644
--- a/common/ext4
+++ b/common/ext4
@@ -242,3 +242,37 @@ _ext4_get_inum_iflags() {
debugfs -R "stat <${inumber}>" "${dev}" 2> /dev/null | \
sed -n 's/^.*Flags: \([0-9a-fx]*\).*$/\1/p'
}
+
+# Helper to dump directory structure with hash info (requires dirdata feature)
+# This is useful for verifying that dirdata is storing hash information
+_dump_dir_structure()
+{
+ local dir=$1
+ local dir_name=$(basename $dir)
+ local expected=$3
+
+ local debugfs_output=$({
+ echo "cd $dir_name"
+ echo "ls -lD ."
+ echo "quit"
+ } | debugfs $SCRATCH_DEV 2>/dev/null)
+
+ # DEBUG: uncomment to see full debugfs output
+ # echo " [DEBUG] debugfs output for $dir_name:"
+ # echo "$debugfs_output" | grep -v "^debugfs:" | sed 's/^/ /'
+
+ # Check if hash data is present (encryption+casefold+dirdata case)
+ # or if fid data is present (dirdata+encryption or dirdata only case)
+ if echo "$debugfs_output" | grep -q "fid="; then
+ local fid_value=$(echo "$debugfs_output" | grep -o "fid=[^ ]*" | head -1 | sed 's/^fid=//')
+ if [ "$fid_value" = "$expected" ]; then
+ echo " Directory structure of $dir_name: OK (dirdata verified)"
+ else
+ echo " Directory structure of $dir_name: FAILED (fid mismatch: got '$fid_value', expected '$expected')"
+ fi
+ elif echo "$debugfs_output" | grep -q "hash="; then
+ echo " Directory structure of $dir_name: OK (dirdata verified)"
+ else
+ echo " Directory structure of $dir_name: FAILED (no dirdata)"
+ fi
+}
--
2.43.7
^ permalink raw reply related
* [RFC PATCH v3 0/6] ext4: tests for the dirdata feature (encryption+casefold, LUFID)
From: Artem Blagodarenko @ 2026-06-24 13:49 UTC (permalink / raw)
To: linux-ext4; +Cc: adilger.kernel, Artem Blagodarenko
These tests cover the ext4 "dirdata" feature (storing extra metadata
in directory entries beyond the file name), sent separately from the
kernel and e2fsprogs dirdata patch series for reference and review.
ext4/064 and ext4/065 verify that encryption and case-insensitive
(casefold) directories continue to work both without and with
dirdata enabled. ext4/066 and ext4/067 exercise the LUFID (Locally
Unique File ID) use of dirdata via a new EXT4_IOC_SET_LUFID ioctl,
using a small set_lufid helper utility added in this series.
Changes in v2:
- Ted Ts'o pointed out that the v1 tests exercised the
encryption+casefold/dirdata feature combination without actually
validating that the encrypted hash was stored as a dirdata
attribute (https://lore.kernel.org/all/20260418214359.GA58909@macsyma-wired.lan/).
ext4/064 and ext4/065 now use the new _dump_dir_structure helper
(debugfs-based) to dump and check the on-disk directory entry
content, confirming the hash is actually present as dirdata rather
than just exercising the feature combination.
- Zorro Lang asked about a confusingly-named helper
(_require_encrypted_casefold vs. _require_scratch_casefold); the
tests now consistently use _require_scratch_casefold.
- Added ext4/066 and ext4/067, plus a new common/ext4 helper and the
src/set_lufid.c utility, to directly verify LUFID data is correctly
stored in and retrieved from dirdata via EXT4_IOC_SET_LUFID, including
in combination with encryption+casefold.
Changes in v3:
- Fixed two off-by-one bugs in src/set_lufid.c, found while testing
the kernel-side EXT4_IOC_SET_LUFID fixes against this suite:
- The default (binary fid array) payload path computed
data_len = sizeof(fid) + 1, copying one byte of stack garbage past
the 16-byte LUFID struct.
- The explicit (argv[3]) payload path computed
data_len = strlen(lufid_data) + 1, treating a NUL terminator as
part of a binary payload that doesn't have one.
Both surfaced as a phantom extra FID in ext4/066 and ext4/067's
dirdata-dump verification once a kernel-side dirdata length
accounting bug was itself fixed -- that kernel bug had been
silently masking this test bug by truncating the same garbage byte
on write.
Artem Blagodarenko (6):
ext4: add common helper to check whether dirdata is applied
ext4/064 encryption + casefold feature combination WITHOUT dirdata
ext4/065 encryption + casefold + dirdata feature combination
ext4: add set_lufid utility
ext4/066: verify LUFID dirdata operations
ext4/067: LUFID and encryption+casefold+dirdata
common/config | 1 +
common/ext4 | 34 +++++++
src/Makefile | 2 +-
src/set_lufid.c | 196 ++++++++++++++++++++++++++++++++++++++++
tests/ext4/064 | 153 ++++++++++++++++++++++++++++++++
tests/ext4/064.out | 17 ++++
tests/ext4/065 | 217 +++++++++++++++++++++++++++++++++++++++++++++
tests/ext4/065.out | 26 ++++++
tests/ext4/066 | 158 +++++++++++++++++++++++++++++++++
tests/ext4/066.out | 4 +
tests/ext4/067 | 137 ++++++++++++++++++++++++++++
tests/ext4/067.out | 4 +
12 files changed, 948 insertions(+), 1 deletion(-)
create mode 100644 src/set_lufid.c
create mode 100755 tests/ext4/064
create mode 100644 tests/ext4/064.out
create mode 100755 tests/ext4/065
create mode 100644 tests/ext4/065.out
create mode 100755 tests/ext4/066
create mode 100644 tests/ext4/066.out
create mode 100755 tests/ext4/067
create mode 100644 tests/ext4/067.out
--
2.43.7
^ permalink raw reply
* [PATCH v4 11/11] ext4: Add EXT4_IOC_SET_LUFID ioctl for setting LUFID on directory entries
From: Artem Blagodarenko @ 2026-06-24 13:36 UTC (permalink / raw)
To: linux-ext4; +Cc: adilger.kernel, Artem Blagodarenko, Andreas Dilger
In-Reply-To: <20260624133642.18438-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Add a new ioctl command that allows setting LUFID (Locally Unique File ID)
data on existing directory entries. This includes:
- ext4_ioctl_set_lufid(): ioctl handler that validates parameters and
calls the underlying implementation
- ext4_set_direntry_lufid(): Core function that performs the operation by:
* Looking up the target directory entry
* Retrieving the associated inode
* Deleting the old entry and re-creating it with LUFID data attached
This implementation requires the dirdata feature to be enabled on the
filesystem and properly handles transactions and inode locking to ensure
consistency.
Signed-off-by: Artem Blagodarenko artem.blagodarenko@gmail.com
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
---
fs/ext4/ext4.h | 15 ++++
fs/ext4/ioctl.c | 84 +++++++++++++++++++++
fs/ext4/namei.c | 155 ++++++++++++++++++++++++++++++++++++++
include/uapi/linux/ext4.h | 13 ++++
4 files changed, 267 insertions(+)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 5674a64f830f..252a5a529205 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1227,6 +1227,7 @@ struct ext4_inode_info {
#ifdef CONFIG_FS_ENCRYPTION
struct fscrypt_inode_info *i_crypt_info;
#endif
+ void *i_dirdata;
};
/*
@@ -2601,6 +2602,18 @@ struct ext4_dirent_hash {
struct ext4_dir_entry_hash dh_hash;
} __packed;
+static inline
+struct ext4_dirent_fid *ext4_dentry_get_fid(struct super_block *sb,
+ struct ext4_dentry_param *p)
+{
+ if (!ext4_has_feature_dirdata(sb))
+ return NULL;
+ if (p && p->edp_magic == EXT4_LUFID_MAGIC)
+ return &p->edp_dfid;
+
+ return NULL;
+}
+
#define EXT4_FT_DIR_CSUM 0xDE
/*
@@ -3302,6 +3315,8 @@ static inline int ext4_init_new_dir(handle_t *handle, struct inode *dir,
}
extern int ext4_dirblock_csum_verify(struct inode *inode,
struct buffer_head *bh);
+extern int ext4_dirdata_set_lufid(struct inode *dir, const char *filename,
+ int namelen, struct ext4_dentry_param *edp);
extern int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
__u32 start_minor_hash, __u32 *next_hash);
extern int ext4_search_dir(struct buffer_head *bh,
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index c8387e6a2c6e..725e46e1e46d 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -1535,6 +1535,87 @@ static int ext4_ioctl_set_tune_sb(struct file *filp,
return ret;
}
+/*
+ * ext4_ioctl_set_lufid() - Set LUFID on a directory entry
+ * @filp: file pointer (parent directory)
+ * @arg: pointer to ext4_set_lufid structure with filename and LUFID data
+ *
+ * This ioctl allows setting LUFID data on an existing
+ * directory entry. It is called on the parent directory with a filename and
+ * LUFID data.
+ */
+static long ext4_ioctl_set_lufid(struct file *filp, unsigned long arg)
+{
+ struct inode *dir = file_inode(filp);
+ struct mnt_idmap *idmap = file_mnt_idmap(filp);
+ struct ext4_set_lufid lufid_args;
+ struct {
+ __u32 edp_magic;
+ struct ext4_dirent_data_header df_header;
+ char df_fid[255];
+ } edp;
+ int err;
+
+ /* Check if parent is a directory */
+ if (!S_ISDIR(dir->i_mode))
+ return -ENOTDIR;
+
+ /* This ioctl mutates directory entries; merely having the directory
+ * open (which only ever requires read access) is not enough */
+ err = inode_permission(idmap, dir, MAY_WRITE);
+ if (err)
+ return err;
+
+ /* Copy arguments from user space */
+ if (copy_from_user(&lufid_args, (struct ext4_set_lufid __user *)arg,
+ sizeof(lufid_args)))
+ return -EFAULT;
+
+ /* Validate parameters */
+ if (lufid_args.esl_name_len == 0 || lufid_args.esl_name_len > EXT4_NAME_LEN)
+ return -EINVAL;
+
+ /* ddh_length (esl_data_len + the header byte below) must itself fit
+ * in the __u8 ddh_length field without wrapping */
+ if (lufid_args.esl_data_len == 0 ||
+ lufid_args.esl_data_len > 255 - sizeof(edp.df_header))
+ return -EINVAL;
+
+ /* Ensure filename is NUL-terminated and unmodified */
+ if (lufid_args.esl_name[lufid_args.esl_name_len - 1] != '\0')
+ return -EINVAL;
+
+ /* '.' and '..' are not ordinary entries -- they must stay the first
+ * two entries in the directory's first block, so they can't go
+ * through the general delete+re-add path this ioctl uses */
+ if (!strcmp(lufid_args.esl_name, ".") || !strcmp(lufid_args.esl_name, ".."))
+ return -EINVAL;
+
+ /* Prepare the dentry param struct with LUFID data. ddh_length is
+ * documented (see struct ext4_dirent_data_header) as the length of
+ * the header plus the whole data blob -- include the header here so
+ * every dirdata reader/writer that takes ddh_length at face value
+ * (e.g. ext4_dirdata_set()'s memcpy) copies the full LUFID payload
+ * instead of silently dropping its last byte. */
+ edp.edp_magic = EXT4_LUFID_MAGIC;
+ edp.df_header.ddh_length = lufid_args.esl_data_len +
+ sizeof(edp.df_header);
+ memcpy(edp.df_fid, lufid_args.esl_data, lufid_args.esl_data_len);
+
+ /* Want write access */
+ err = mnt_want_write_file(filp);
+ if (err)
+ return err;
+
+ /* Call the helper function to do the actual work */
+ err = ext4_dirdata_set_lufid(dir, lufid_args.esl_name,
+ lufid_args.esl_name_len - 1,
+ (struct ext4_dentry_param *)&edp);
+
+ mnt_drop_write_file(filp);
+ return err;
+}
+
static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct inode *inode = file_inode(filp);
@@ -1921,6 +2002,8 @@ static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
(void __user *)arg);
case EXT4_IOC_SET_TUNE_SB_PARAM:
return ext4_ioctl_set_tune_sb(filp, (void __user *)arg);
+ case EXT4_IOC_SET_LUFID:
+ return ext4_ioctl_set_lufid(filp, arg);
default:
return -ENOTTY;
}
@@ -2000,6 +2083,7 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case FS_IOC_SETFSLABEL:
case EXT4_IOC_GETFSUUID:
case EXT4_IOC_SETFSUUID:
+ case EXT4_IOC_SET_LUFID:
break;
default:
return -ENOIOCTLCMD;
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 6fba1a7c0876..3aeea503f12d 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2319,6 +2319,8 @@ static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
if (ext4_has_feature_metadata_csum(inode->i_sb))
csum_size = sizeof(struct ext4_dir_entry_tail);
+ dfid = ext4_dentry_get_fid(inode->i_sb,
+ (struct ext4_dentry_param *)EXT4_I(inode)->i_dirdata);
if (!de) {
if (dfid)
dlen = dfid->df_header.ddh_length;
@@ -2665,6 +2667,7 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
{
struct inode *dir = d_inode(dentry->d_parent);
+ EXT4_I(inode)->i_dirdata = dentry->d_fsdata;
if (fscrypt_is_nokey_name(dentry))
return -ENOKEY;
return __ext4_add_entry(handle, dir, &dentry->d_name, inode);
@@ -4426,6 +4429,158 @@ static int ext4_rename2(struct mnt_idmap *idmap,
return ext4_rename(idmap, old_dir, old_dentry, new_dir, new_dentry, flags);
}
+/*
+ * ext4_dirdata_set_lufid() - Set LUFID data on an existing directory entry
+ * @dir: parent directory inode
+ * @filename: name of the file in the directory
+ * @namelen: length of filename
+ * @edp: pointer to initialized dentry param with LUFID data
+ *
+ * This function finds an existing directory entry, deletes it, and re-creates it
+ * with LUFID data attached. Used by the EXT4_IOC_SET_LUFID ioctl.
+ *
+ * Returns 0 on success, negative error code on failure.
+ */
+int ext4_dirdata_set_lufid(struct inode *dir, const char *filename,
+ int namelen, struct ext4_dentry_param *edp)
+{
+ struct super_block *sb = dir->i_sb;
+ struct ext4_filename fname;
+ struct ext4_dir_entry_2 *de = NULL;
+ struct buffer_head *bh = NULL;
+ struct inode *inode = NULL;
+ handle_t *handle = NULL;
+ struct qstr d_name;
+ void *old_dirdata = NULL;
+ int err = 0;
+
+ /* Check if dirdata feature is enabled */
+ if (!ext4_has_feature_dirdata(sb))
+ return -ENOTSUPP;
+
+ if (namelen > EXT4_NAME_LEN)
+ return -ENAMETOOLONG;
+ if (namelen != strnlen(filename, namelen + 1))
+ return -EINVAL;
+
+ /* Setup the filename for lookup */
+ d_name.name = filename;
+ d_name.len = namelen;
+
+ /* Lookup the filename in the directory */
+ err = ext4_fname_setup_filename(dir, &d_name, 0, &fname);
+ if (err)
+ goto out_free;
+
+ bh = ext4_find_entry(dir, &d_name, &de, NULL);
+ if (!bh) {
+ err = -ENOENT;
+ goto out_free;
+ }
+
+ /* Get the inode number from the directory entry */
+ inode = ext4_iget(sb, le32_to_cpu(de->inode), EXT4_IGET_NORMAL);
+ if (IS_ERR(inode)) {
+ err = PTR_ERR(inode);
+ inode = NULL;
+ goto out_brelse;
+ }
+
+ /* Start a transaction */
+ handle = ext4_journal_start(dir, EXT4_HT_DIR,
+ 2 * EXT4_DATA_TRANS_BLOCKS(sb) +
+ EXT4_INDEX_EXTRA_TRANS_BLOCKS);
+ if (IS_ERR(handle)) {
+ err = PTR_ERR(handle);
+ handle = NULL;
+ goto out_iput;
+ }
+
+ inode_lock(dir);
+
+ /* EXT4_I(inode)->i_dirdata below is a *shared* per-inode field used
+ * to smuggle the LUFID payload into ext4_add_entry(); locking only
+ * dir does not stop a concurrent EXT4_IOC_SET_LUFID call targeting a
+ * different hardlink of the same inode (different dir, same inode)
+ * from clobbering it mid-call with its own stack-local pointer.
+ * Lock the target inode too, consistently dir-then-inode, to
+ * serialize the i_dirdata set/use/restore window below. */
+ if (inode != dir)
+ inode_lock_nested(inode, I_MUTEX_NONDIR2);
+
+ /* Delete the old entry */
+ err = ext4_delete_entry(handle, dir, de, bh);
+ if (err)
+ goto out_unlock;
+
+ brelse(bh);
+ bh = NULL;
+
+ /* Re-add the entry with LUFID data
+ * We set i_dirdata before adding so the entry can include it
+ */
+ old_dirdata = EXT4_I(inode)->i_dirdata;
+ EXT4_I(inode)->i_dirdata = edp;
+
+ /* Use ext4_add_entry() to properly handle hash table management
+ * and block splitting, just like rename does. This ensures the entry
+ * is placed in the correct hash block and avoids breaking dirhash.
+ */
+ {
+ struct dentry parent_dentry = { .d_inode = dir };
+ struct dentry new_dentry = {
+ .d_name = d_name,
+ .d_parent = &parent_dentry,
+ .d_inode = inode, /* Same inode (in-place update) */
+ .d_fsdata = edp, /* required */
+ };
+ err = ext4_add_entry(handle, &new_dentry, inode);
+ }
+ EXT4_I(inode)->i_dirdata = old_dirdata;
+
+ if (err) {
+ /*
+ * The original entry was already removed above and the
+ * re-add with the new LUFID failed; try to restore the
+ * original entry so the inode isn't left without any
+ * directory entry pointing at it.
+ */
+ struct dentry parent_dentry = { .d_inode = dir };
+ struct dentry orig_dentry = {
+ .d_name = d_name,
+ .d_parent = &parent_dentry,
+ .d_inode = inode,
+ };
+ int rollback_err = ext4_add_entry(handle, &orig_dentry, inode);
+
+ if (rollback_err)
+ EXT4_ERROR_INODE(dir,
+ "Failed to set LUFID on '%.*s' (err=%d) and failed to restore the original directory entry (err=%d); inode %llu may be orphaned",
+ namelen, filename, err, rollback_err,
+ inode->i_ino);
+ goto out_unlock;
+ }
+
+ /* Update inode times */
+ inode_set_ctime_current(dir);
+ inode_inc_iversion(dir);
+ ext4_mark_inode_dirty(handle, dir);
+
+out_unlock:
+ if (inode != dir)
+ inode_unlock(inode);
+ inode_unlock(dir);
+ ext4_journal_stop(handle);
+out_iput:
+ iput(inode);
+out_brelse:
+ brelse(bh);
+out_free:
+ ext4_fname_free_filename(&fname);
+
+ return err;
+}
+
/*
* directories can handle most operations...
*/
diff --git a/include/uapi/linux/ext4.h b/include/uapi/linux/ext4.h
index 9c683991c32f..9fab8978843b 100644
--- a/include/uapi/linux/ext4.h
+++ b/include/uapi/linux/ext4.h
@@ -35,6 +35,7 @@
#define EXT4_IOC_SETFSUUID _IOW('f', 44, struct fsuuid)
#define EXT4_IOC_GET_TUNE_SB_PARAM _IOR('f', 45, struct ext4_tune_sb_params)
#define EXT4_IOC_SET_TUNE_SB_PARAM _IOW('f', 46, struct ext4_tune_sb_params)
+#define EXT4_IOC_SET_LUFID _IOW('f', 47, struct ext4_set_lufid)
#define EXT4_IOC_SHUTDOWN _IOR('X', 125, __u32)
@@ -92,6 +93,18 @@ struct move_extent {
__u64 moved_len; /* moved block length */
};
+/*
+ * Structure for EXT4_IOC_SET_LUFID
+ * Sets LUFID on a directory entry
+ * Called on parent directory with filename and LUFID data as arguments
+ */
+struct ext4_set_lufid {
+ __u8 esl_name_len; /* length of filename */
+ char esl_name[255 + 1]; /* filename (NUL-terminated) */
+ __u8 esl_data_len; /* length of LUFID data */
+ char esl_data[255]; /* LUFID data (raw bytes) */
+};
+
/*
* Flags used by EXT4_IOC_SHUTDOWN
*/
--
2.43.7
^ permalink raw reply related
* [PATCH v4 10/11] ext4: add dirdata set/get helpers
From: Artem Blagodarenko @ 2026-06-24 13:36 UTC (permalink / raw)
To: linux-ext4; +Cc: adilger.kernel, Artem Blagodarenko, Andreas Dilger
In-Reply-To: <20260624133642.18438-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Add helpers to set and retrieve dirdata payload and hook them up at
the appropriate call sites.
Enable dirdata for casefold+encryption hashes and storing unique
128-bit file identifier in the directory entry for testing.
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
---
foofile.txt | 0
fs/ext4/ext4.h | 4 +
fs/ext4/inline.c | 6 +-
fs/ext4/namei.c | 227 +++++++++++++++++++++++++++++++++++++++++------
4 files changed, 207 insertions(+), 30 deletions(-)
diff --git a/foofile.txt b/foofile.txt
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 1e61ce13ed07..5674a64f830f 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3874,6 +3874,10 @@ extern int __ext4_unlink(struct inode *dir, const struct qstr *d_name,
struct inode *inode, struct dentry *dentry);
extern int __ext4_link(struct inode *dir, struct inode *inode,
const struct qstr *d_name, struct dentry *dentry);
+extern unsigned char ext4_dirdata_get(struct ext4_dir_entry_2 *de,
+ struct inode *dir,
+ struct ext4_dirent_fid *lufid,
+ struct dx_hash_info *hinfo);
#define S_SHIFT 12
static const unsigned char ext4_type_by_mode[(S_IFMT >> S_SHIFT) + 1] = {
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 1fff4defd45b..32b4ff83d4df 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -1350,10 +1350,8 @@ int ext4_inlinedir_to_tree(struct file *dir_file,
}
}
- if (ext4_hash_in_dirent(dir)) {
- hinfo->hash = EXT4_DIRENT_HASH(de);
- hinfo->minor_hash = EXT4_DIRENT_MINOR_HASH(de);
- } else {
+ if (!(ext4_dirdata_get(de, dir, NULL, hinfo) &
+ EXT4_DIRENT_CFHASH)) {
err = ext4fs_dirhash(dir, de->name, de->name_len, hinfo);
if (err) {
ret = err;
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 91def9e0f84d..6fba1a7c0876 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1108,22 +1108,22 @@ static int htree_dirblock_to_tree(struct file *dir_file,
/* silently ignore the rest of the block */
break;
}
- if (ext4_hash_in_dirent(dir)) {
- if (de->name_len && de->inode) {
- hinfo->hash = EXT4_DIRENT_HASH(de);
- hinfo->minor_hash = EXT4_DIRENT_MINOR_HASH(de);
- } else {
- hinfo->hash = 0;
- hinfo->minor_hash = 0;
- }
+ if (de->name_len && de->inode) {
+ /* check for saved hash first, or generate it from name */
+ if (!(ext4_dirdata_get(de, dir, NULL, hinfo) &
+ EXT4_DIRENT_CFHASH)) {
+ err = ext4fs_dirhash(dir, de->name,
+ de->name_len, hinfo);
+ if (err < 0) {
+ count = err;
+ goto errout;
+ }
+ }
} else {
- err = ext4fs_dirhash(dir, de->name,
- de->name_len, hinfo);
- if (err < 0) {
- count = err;
- goto errout;
- }
+ hinfo->hash = 0;
+ hinfo->minor_hash = 0;
}
+
if ((hinfo->hash < start_hash) ||
((hinfo->hash == start_hash) &&
(hinfo->minor_hash < start_minor_hash)))
@@ -1301,9 +1301,191 @@ static inline int search_dirblock(struct buffer_head *bh,
*/
/*
- * Create map of hash values, offsets, and sizes, stored at end of block.
- * Returns number of entries mapped.
+ * ext4_dirdata_get() - Read dirdata fields from a directory entry.
+ * @de: directory entry
+ * @dir: directory inode (used for fscrypt+casefold hash fallback)
+ * @dfid: if non-NULL and EXT4_DIRENT_LUFID is set, LUFID data is copied
+ * here
+ * @hinfo: if non-NULL, receives the casefold hash and minor hash
+ *
+ * Reads any dirdata stored in @de. If the dirdata feature is not enabled,
+ * falls back to reading the hash stored inline after the filename (for
+ * compatibility with the older casefold+fscrypt format).
+ *
+ * Returns a bitmask of EXT4_DIRENT_* flags indicating which fields were read.
+ */
+unsigned char ext4_dirdata_get(struct ext4_dir_entry_2 *de, struct inode *dir,
+ struct ext4_dirent_fid *dfid,
+ struct dx_hash_info *hinfo)
+{
+ unsigned char ret = 0;
+ unsigned int data_offset = de->name_len + 1;
+ unsigned int rec_len = ext4_rec_len_from_disk(de->rec_len,
+ dir->i_sb->s_blocksize);
+
+ /* data_offset is relative to de->name, which itself starts
+ * EXT4_BASE_DIR_LEN bytes into the entry -- rec_len is relative to
+ * the start of the entry, so add the header size before comparing,
+ * or this lets reads run EXT4_BASE_DIR_LEN bytes past the entry. */
+ if (EXT4_BASE_DIR_LEN + data_offset > rec_len)
+ return ret;
+
+ /* compatibility: hash stored inline after filename (no dirdata) */
+ if (hinfo && !ext4_has_feature_dirdata(dir->i_sb) &&
+ ext4_hash_in_dirent(dir)) {
+ hinfo->hash = EXT4_DIRENT_HASH(de);
+ hinfo->minor_hash = EXT4_DIRENT_MINOR_HASH(de);
+ ret |= EXT4_DIRENT_CFHASH;
+
+ return ret;
+ }
+
+ /* EXT4_DIRENT_* are not expected without flag in i_sb */
+ if (de->file_type & EXT4_DIRENT_LUFID) {
+ struct ext4_dirent_fid *disk_fid =
+ (struct ext4_dirent_fid *)(de->name + data_offset);
+ unsigned int dlen;
+
+ if (EXT4_BASE_DIR_LEN + data_offset + sizeof(disk_fid->df_header) > rec_len)
+ return ret;
+
+ dlen = disk_fid->df_header.ddh_length;
+ if (dlen < sizeof(*disk_fid) ||
+ EXT4_BASE_DIR_LEN + data_offset + dlen > rec_len)
+ return ret;
+
+ if (dfid) {
+ /* copy the whole record (header + fid), not just the fid
+ * payload -- dlen already includes the header's length */
+ memcpy(dfid, disk_fid, dlen);
+ ret |= EXT4_DIRENT_LUFID;
+ }
+ data_offset += dlen;
+ }
+
+ /* Skip INO64 for now*/
+ if (de->file_type & EXT4_DIRENT_INO64) {
+ struct ext4_dirent_data_header *ddh =
+ (struct ext4_dirent_data_header *)(de->name + data_offset);
+ unsigned int dlen;
+
+ if (EXT4_BASE_DIR_LEN + data_offset + sizeof(*ddh) > rec_len)
+ return ret;
+
+ dlen = ddh->ddh_length;
+ if (dlen < sizeof(*ddh) ||
+ EXT4_BASE_DIR_LEN + data_offset + dlen > rec_len)
+ return ret;
+
+ data_offset += dlen;
+ }
+
+ if (!hinfo)
+ return ret;
+
+ if (de->file_type & EXT4_DIRENT_CFHASH) {
+ struct ext4_dirent_hash *dh =
+ (struct ext4_dirent_hash *)(de->name + data_offset);
+ unsigned int dlen;
+
+ dlen = dh->dh_header.ddh_length;
+ if (dlen < sizeof(*dh) ||
+ EXT4_BASE_DIR_LEN + data_offset + dlen > rec_len)
+ return ret;
+
+ hinfo->hash = le32_to_cpu(dh->dh_hash.hash);
+ hinfo->minor_hash = le32_to_cpu(dh->dh_hash.minor_hash);
+ ret |= EXT4_DIRENT_CFHASH;
+ }
+
+ return ret;
+}
+
+/*
+ * ext4_dirdata_set() - Write dirdata fields into a directory entry.
+ * @de: directory entry (name must already be set)
+ * @dir: directory inode
+ * @data: LUFID data to store (or NULL)
+ * @fname: filename info carrying the casefold hash
+ *
+ * Writes any required dirdata into @de after the filename. If the dirdata
+ * feature is not enabled, falls back to writing the hash inline after the
+ * filename (for compatibility with the older casefold+fscrypt format).
*/
+static void ext4_dirdata_set(struct ext4_dir_entry_2 *de, struct inode *dir,
+ struct ext4_dirent_fid *dfid,
+ struct ext4_filename *fname)
+{
+ struct dx_hash_info *hinfo = &fname->hinfo;
+ unsigned int data_offset = de->name_len + 1;
+ unsigned int rec_len = ext4_rec_len_from_disk(de->rec_len,
+ dir->i_sb->s_blocksize);
+
+ /* de->name[] is declared with a fixed EXT4_NAME_LEN size, but the
+ * real backing storage is this entry's rec_len-sized space in the
+ * directory block; a max-length name (name_len == EXT4_NAME_LEN)
+ * leaves no declared array slot for the NUL terminator below, which
+ * FORTIFY_SOURCE treats as an out-of-bounds array write regardless
+ * of how much real space the entry has. */
+ if (dfid && de->name_len >= EXT4_NAME_LEN) {
+ EXT4_ERROR_INODE(dir, "Can not insert FID: name_len too long");
+ return;
+ }
+
+ /* always clear the gap byte at de->name[de->name_len], even when no
+ * FID is being appended -- otherwise it's never initialized before
+ * dirdata is written right after it, leaking a byte of stale memory
+ * to disk. Skip it for a max-length name: there's no declared array
+ * slot for it, and no dirdata can be appended in that case anyway
+ * (rejected above for dfid; data_offset would already be >= rec_len
+ * for any other dirdata kind). */
+ if (de->name_len < EXT4_NAME_LEN)
+ de->name[de->name_len] = 0;
+
+ if (dfid) {
+ unsigned int dlen = dfid->df_header.ddh_length;
+
+ if (EXT4_BASE_DIR_LEN + data_offset + dlen > rec_len) {
+ EXT4_ERROR_INODE(dir, "Can not insert FID");
+ return;
+ }
+
+ memcpy(&de->name[de->name_len + 1], dfid,
+ dlen);
+ de->file_type |= EXT4_DIRENT_LUFID;
+ data_offset += dlen;
+ }
+
+ if (ext4_hash_in_dirent(dir)) {
+ if (ext4_has_feature_dirdata(dir->i_sb)) {
+ struct ext4_dirent_hash *dh =
+ (struct ext4_dirent_hash *)(de->name + data_offset);
+
+ if (EXT4_BASE_DIR_LEN + data_offset + sizeof(*dh) > rec_len) {
+ EXT4_ERROR_INODE(dir, "Can not insert dhash dirdata");
+ return;
+ }
+
+ dh->dh_header.ddh_length = sizeof(*dh);
+ dh->dh_hash.hash = cpu_to_le32(hinfo->hash);
+ dh->dh_hash.minor_hash = cpu_to_le32(hinfo->minor_hash);
+ de->file_type |= EXT4_DIRENT_CFHASH;
+ } else {
+ /* Compatibility: store hash inline after filename */
+ if (EXT4_BASE_DIR_LEN + data_offset +
+ sizeof(struct ext4_dir_entry_hash) > rec_len) {
+ EXT4_ERROR_INODE(dir, "Can not insert dhash");
+ return;
+ }
+
+ EXT4_DIRENT_HASHES(de)->hash = cpu_to_le32(hinfo->hash);
+ EXT4_DIRENT_HASHES(de)->minor_hash =
+ cpu_to_le32(hinfo->minor_hash);
+ }
+ }
+}
+
+
static int dx_make_map(struct inode *dir, struct buffer_head *bh,
struct dx_hash_info *hinfo,
struct dx_map_entry *map_tail)
@@ -1323,9 +1505,8 @@ static int dx_make_map(struct inode *dir, struct buffer_head *bh,
((char *)de) - base))
return -EFSCORRUPTED;
if (de->name_len && de->inode) {
- if (ext4_hash_in_dirent(dir))
- h.hash = EXT4_DIRENT_HASH(de);
- else {
+ if (!(ext4_dirdata_get(de, dir, NULL, &h) &
+ EXT4_DIRENT_CFHASH)) {
int err = ext4fs_dirhash(dir, de->name,
de->name_len, &h);
if (err < 0)
@@ -2113,13 +2294,7 @@ void ext4_insert_dentry_data(struct inode *dir, struct inode *inode,
ext4_set_de_type(inode->i_sb, de, inode->i_mode);
de->name_len = fname_len(fname);
memcpy(de->name, fname_name(fname), fname_len(fname));
- if (ext4_hash_in_dirent(dir)) {
- struct dx_hash_info *hinfo = &fname->hinfo;
-
- EXT4_DIRENT_HASHES(de)->hash = cpu_to_le32(hinfo->hash);
- EXT4_DIRENT_HASHES(de)->minor_hash =
- cpu_to_le32(hinfo->minor_hash);
- }
+ ext4_dirdata_set(de, dir, data, fname);
}
/*
--
2.43.7
^ permalink raw reply related
* [PATCH v4 09/11] ext4: dirdata feature
From: Artem Blagodarenko @ 2026-06-24 13:36 UTC (permalink / raw)
To: linux-ext4
Cc: adilger.kernel, Artem Blagodarenko, Pravin Shelar, Andreas Dilger
In-Reply-To: <20260624133642.18438-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
When fscrypt and casefold are enabled together for a directory,
all ext4_dir_entry[_2] in that directory store a n 8-byte hash
of the filename after 'name' between 'name_len' and 'rec_len'.
However, there is no clear indication there is important data
stored in these bytes, which are only for padding and alignment
in other directory entries. This adds complexity to code handling
the on-disk directory entries, and there is no provision for other
metadata to be stored in each dir entry after 'name'.
The dirdata feature adds a mechanism to store multiple metadata
entries in each dir entry after 'name' (including the fchash).
The unused high 4 bits of 'file_type' are used to indicate whether
additional data fields are stored after 'name'. If a bit is set,
the corresponding dirdata record is present, starting after a NUL
filename terminator. If present, a record starts with a 1-byte
length (including the length byte itself) and the data immediately
follows the length byte without any alignment.
This allows up to four different dirdata records to be stored in
each entry, and allows unhandled record bytes to be skipped without
having to process the contents, providing forward compatibility.
If and when the fourth and last dirdata record is needed, it is
recommended to further subdivide it into sub-records, with
the first byte being the total length, and then there being a
second byte that gives the sub-record length, etc. as long as
the total record length is less than 255 bytes. However, this
would not affect compatibility with the current code since the
record length would allow it to be skipped without processing.
Signed-off-by: Pravin Shelar <pravin.shelar@sun.com>
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
---
fs/ext4/ext4.h | 27 +++++++++++++++++++++------
fs/ext4/inline.c | 23 +++++++++++++++++++----
fs/ext4/namei.c | 45 +++++++++++++++++++++++----------------------
fs/ext4/sysfs.c | 2 ++
4 files changed, 65 insertions(+), 32 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 2fc9fa6d3021..1e61ce13ed07 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2334,6 +2334,7 @@ EXT4_FEATURE_INCOMPAT_FUNCS(casefold, CASEFOLD)
EXT4_FEATURE_INCOMPAT_FLEX_BG| \
EXT4_FEATURE_INCOMPAT_EA_INODE| \
EXT4_FEATURE_INCOMPAT_MMP | \
+ EXT4_FEATURE_INCOMPAT_DIRDATA | \
EXT4_FEATURE_INCOMPAT_INLINE_DATA | \
EXT4_FEATURE_INCOMPAT_ENCRYPT | \
EXT4_FEATURE_INCOMPAT_CASEFOLD | \
@@ -3035,10 +3036,18 @@ extern int ext4_find_dest_de(struct inode *dir, struct buffer_head *bh,
struct ext4_filename *fname,
struct ext4_dir_entry_2 **dest_de,
int dlen);
-void ext4_insert_dentry(struct inode *dir, struct inode *inode,
- struct ext4_dir_entry_2 *de,
- int buf_size,
- struct ext4_filename *fname);
+void ext4_insert_dentry_data(struct inode *dir, struct inode *inode,
+ struct ext4_dir_entry_2 *de,
+ int buf_size,
+ struct ext4_filename *fname,
+ void *data);
+static inline void ext4_insert_dentry(struct inode *dir, struct inode *inode,
+ struct ext4_dir_entry_2 *de,
+ int buf_size,
+ struct ext4_filename *fname)
+{
+ ext4_insert_dentry_data(dir, inode, de, buf_size, fname, NULL);
+}
static inline void ext4_update_dx_flag(struct inode *inode)
{
if (!ext4_has_feature_dir_index(inode->i_sb) &&
@@ -3283,8 +3292,14 @@ extern int ext4_ext_migrate(struct inode *);
extern int ext4_ind_migrate(struct inode *inode);
/* namei.c */
-extern int ext4_init_new_dir(handle_t *handle, struct inode *dir,
- struct inode *inode);
+extern int ext4_init_new_dir_data(handle_t *handle, struct inode *dir,
+ struct inode *inode,
+ const void *data1, const void *data2);
+static inline int ext4_init_new_dir(handle_t *handle, struct inode *dir,
+ struct inode *inode)
+{
+ return ext4_init_new_dir_data(handle, dir, inode, NULL, NULL);
+}
extern int ext4_dirblock_csum_verify(struct inode *inode,
struct buffer_head *bh);
extern int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 5b3faacdf143..1fff4defd45b 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -973,11 +973,16 @@ static int ext4_add_dirent_to_inline(handle_t *handle,
struct ext4_iloc *iloc,
void *inline_start, int inline_size)
{
- int err;
+ int err, dlen = 0;
struct ext4_dir_entry_2 *de;
+ unsigned char *data = NULL;
+
+ /* Deliver data in any appropriate way here. Now it is NULL */
+ if (data)
+ dlen = (*data) + 1;
err = ext4_find_dest_de(dir, iloc->bh, inline_start,
- inline_size, fname, &de, 0);
+ inline_size, fname, &de, dlen);
if (err)
return err;
@@ -986,7 +991,7 @@ static int ext4_add_dirent_to_inline(handle_t *handle,
EXT4_JTR_NONE);
if (err)
return err;
- ext4_insert_dentry(dir, inode, de, inline_size, fname);
+ ext4_insert_dentry_data(dir, inode, de, inline_size, fname, NULL);
ext4_show_inline_dir(dir, iloc->bh, inline_start, inline_size);
@@ -1326,7 +1331,17 @@ int ext4_inlinedir_to_tree(struct file *dir_file,
pos = EXT4_INLINE_DOTDOT_SIZE;
} else {
de = (struct ext4_dir_entry_2 *)(dir_buf + pos);
- pos += ext4_rec_len_from_disk(de->rec_len, inline_size);
+ /* Use ext4_dir_entry_len to account for dirdata extensions.
+ * This buffer is the inline-data buffer (inline_size bytes),
+ * not a full directory block -- pass the real buffer size so
+ * a corrupted/sentinel on-disk rec_len doesn't get decoded as
+ * a full block's worth of bytes. */
+ pos += ext4_dir_entry_len(de, inline_size, dir);
+ /* Validate pos doesn't exceed buffer to prevent use-after-free */
+ if (pos > inline_size) {
+ ret = count;
+ goto out;
+ }
if (ext4_check_dir_entry(inode, dir_file, de,
iloc.bh, dir_buf,
inline_size, pos)) {
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 73c8f1b399ef..91def9e0f84d 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -401,23 +401,26 @@ static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
{
struct ext4_dir_entry_2 *de;
struct dx_root_info *root;
- int count_offset;
+ int count_offset, dotdot_rec_len;
int blocksize = EXT4_BLOCK_SIZE(inode->i_sb);
unsigned int rlen = ext4_rec_len_from_disk(dirent->rec_len, blocksize);
- if (rlen == blocksize)
+ if (rlen == blocksize) {
count_offset = sizeof(struct dx_node);
- else if (rlen == 12) {
- de = (struct ext4_dir_entry_2 *)(((void *)dirent) + 12);
- if (ext4_rec_len_from_disk(de->rec_len, blocksize) != blocksize - 12)
+ } else {
+ de = (struct ext4_dir_entry_2 *)(((char *)dirent) + rlen);
+ if (le16_to_cpu(de->rec_len) != (blocksize - rlen))
return NULL;
- root = (struct dx_root_info *)(((void *)de + 12));
+ /* de->rec_len covers whole dx_root block, calculate actual length.
+ * This is the '..' entry, which never carries the casefold+fscrypt
+ * hash, so pass NULL for dir regardless of the directory's flags */
+ dotdot_rec_len = ext4_dir_entry_len(de, blocksize, NULL);
+ root = (struct dx_root_info *)(((char *)de + dotdot_rec_len));
if (root->reserved_zero ||
root->info_length != sizeof(struct dx_root_info))
return NULL;
- count_offset = 32;
- } else
- return NULL;
+ count_offset = root->info_length + rlen + dotdot_rec_len;
+ }
if (offset)
*offset = count_offset;
@@ -716,7 +719,7 @@ static struct stats dx_show_leaf(struct inode *dir,
(unsigned) ((char *) de - base));
#endif
}
- space += ext4_dir_rec_len(de->name_len, dir);
+ space += ext4_dir_entry_len(de, size, dir);
names++;
}
de = ext4_next_entry(de, size);
@@ -2090,13 +2093,10 @@ int ext4_find_dest_de(struct inode *dir, struct buffer_head *bh,
return 0;
}
-void ext4_insert_dentry(struct inode *dir,
- struct inode *inode,
- struct ext4_dir_entry_2 *de,
- int buf_size,
- struct ext4_filename *fname)
+void ext4_insert_dentry_data(struct inode *dir, struct inode *inode,
+ struct ext4_dir_entry_2 *de, int buf_size,
+ struct ext4_filename *fname, void *data)
{
-
int nlen, rlen;
nlen = ext4_dir_entry_len(de, buf_size, dir);
@@ -2138,15 +2138,15 @@ static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
unsigned int blocksize = dir->i_sb->s_blocksize;
int csum_size = 0;
int err, err2, dlen = 0;
- unsigned char *data = NULL;
+ struct ext4_dirent_fid *dfid = NULL;
/* Deliver data in any appropriate way here. Now it is NULL */
if (ext4_has_feature_metadata_csum(inode->i_sb))
csum_size = sizeof(struct ext4_dir_entry_tail);
if (!de) {
- if (data)
- dlen = (*data) + 1;
+ if (dfid)
+ dlen = dfid->df_header.ddh_length;
err = ext4_find_dest_de(dir, bh, bh->b_data,
blocksize - csum_size, fname, &de, dlen);
if (err)
@@ -2161,7 +2161,7 @@ static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
}
/* By now the buffer is marked for journaling */
- ext4_insert_dentry(dir, inode, de, blocksize, fname);
+ ext4_insert_dentry_data(dir, inode, de, blocksize, fname, dfid);
/*
* XXX shouldn't update any times until successful
@@ -3000,8 +3000,9 @@ int ext4_init_dirblock(handle_t *handle, struct inode *inode,
return ext4_handle_dirty_dirblock(handle, inode, bh);
}
-int ext4_init_new_dir(handle_t *handle, struct inode *dir,
- struct inode *inode)
+int ext4_init_new_dir_data(handle_t *handle, struct inode *dir,
+ struct inode *inode,
+ const void *data1, const void *data2)
{
struct buffer_head *dir_block = NULL;
ext4_lblk_t block = 0;
diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
index 923b375e017f..80074fb15ee9 100644
--- a/fs/ext4/sysfs.c
+++ b/fs/ext4/sysfs.c
@@ -362,6 +362,7 @@ EXT4_ATTR_FEATURE(verity);
#endif
EXT4_ATTR_FEATURE(metadata_csum_seed);
EXT4_ATTR_FEATURE(fast_commit);
+EXT4_ATTR_FEATURE(dirdata);
#if IS_ENABLED(CONFIG_UNICODE) && defined(CONFIG_FS_ENCRYPTION)
EXT4_ATTR_FEATURE(encrypted_casefold);
#endif
@@ -385,6 +386,7 @@ static struct attribute *ext4_feat_attrs[] = {
#endif
ATTR_LIST(metadata_csum_seed),
ATTR_LIST(fast_commit),
+ ATTR_LIST(dirdata),
#if IS_ENABLED(CONFIG_UNICODE) && defined(CONFIG_FS_ENCRYPTION)
ATTR_LIST(encrypted_casefold),
#endif
--
2.43.7
^ permalink raw reply related
* [PATCH v4 08/11] ext4: rename ext4_dir_rec_len() and clarify dirdata usage
From: Artem Blagodarenko @ 2026-06-24 13:36 UTC (permalink / raw)
To: linux-ext4; +Cc: adilger.kernel, Artem Blagodarenko, Andreas Dilger
In-Reply-To: <20260624133642.18438-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Rename ext4_dir_rec_len() to ext4_dirent_rec_len() to better
reflect that it computes the record length for a directory
entry based on the provided name length.
Update the comment to clarify handling of dirdata-enabled
directories and document the use of ext4_dir_entry_len()
when dirdata is present.
No functional changes.
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
---
fs/ext4/dir.c | 9 +++--
fs/ext4/ext4.h | 14 +++++---
fs/ext4/inline.c | 14 ++++----
fs/ext4/namei.c | 89 ++++++++++++++++++++++++++++++++----------------
4 files changed, 80 insertions(+), 46 deletions(-)
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 17edd678fa87..d22b09f86365 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -89,16 +89,15 @@ int __ext4_check_dir_entry(const char *function, unsigned int line,
bool fake = is_fake_dir_entry(de);
bool has_csum = ext4_has_feature_metadata_csum(dir->i_sb);
- if (unlikely(rlen < ext4_dir_rec_len(1, fake ? NULL : dir)))
+ if (unlikely(rlen < ext4_dirent_rec_len(1, fake ? NULL : dir)))
error_msg = "rec_len is smaller than minimal";
else if (unlikely(rlen % 4 != 0))
error_msg = "rec_len % 4 != 0";
- else if (unlikely(rlen < ext4_dir_rec_len(de->name_len,
- fake ? NULL : dir)))
+ else if (unlikely(rlen < ext4_dir_entry_len(de, size, fake ? NULL : dir)))
error_msg = "rec_len is too small for name_len";
else if (unlikely(next_offset > size))
error_msg = "directory entry overrun";
- else if (unlikely(next_offset > size - ext4_dir_rec_len(1,
+ else if (unlikely(next_offset > size - ext4_dirent_rec_len(1,
has_csum ? NULL : dir) &&
next_offset != size))
error_msg = "directory entry too close to block end";
@@ -245,7 +244,7 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
* failure will be detected in the
* dirent test below. */
if (ext4_rec_len_from_disk(de->rec_len,
- sb->s_blocksize) < ext4_dir_rec_len(1,
+ sb->s_blocksize) < ext4_dirent_rec_len(1,
inode))
break;
i += ext4_rec_len_from_disk(de->rec_len,
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index a369a0cd04bc..2fc9fa6d3021 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2616,11 +2616,16 @@ struct ext4_dirent_hash {
* casefolded and encrypted need to store the hash as well, so we add room for
* ext4_extended_dir_entry_2. For all entries related to '.' or '..' you should
* pass NULL for dir, as those entries do not use the extra fields.
+ *
+ * For directories with the dirdata feature, extra data may follow the filename.
+ * Use ext4_dir_entry_len() to compute the length of a directory entry
+ * including any dirdata, or ext4_dirent_rec_len() directly when the total
+ * name_len (including dirdata length) is already known.
*/
-static inline unsigned int ext4_dir_rec_len(__u8 name_len,
+static inline unsigned int ext4_dirent_rec_len(unsigned int name_len,
const struct inode *dir)
{
- int rec_len = (name_len + 8 + EXT4_DIR_ROUND);
+ unsigned int rec_len = (name_len + 8 + EXT4_DIR_ROUND);
if (dir && ext4_hash_in_dirent(dir))
rec_len += sizeof(struct ext4_dir_entry_hash);
@@ -3028,7 +3033,8 @@ extern void ext4_htree_free_dir_info(struct dir_private_info *p);
extern int ext4_find_dest_de(struct inode *dir, struct buffer_head *bh,
void *buf, int buf_size,
struct ext4_filename *fname,
- struct ext4_dir_entry_2 **dest_de);
+ struct ext4_dir_entry_2 **dest_de,
+ int dlen);
void ext4_insert_dentry(struct inode *dir, struct inode *inode,
struct ext4_dir_entry_2 *de,
int buf_size,
@@ -4148,7 +4154,7 @@ static inline unsigned int ext4_dir_entry_len(struct ext4_dir_entry_2 *de,
unsigned int rec_len = ext4_rec_len_from_disk(de->rec_len, blocksize);
unsigned int dirdata = ext4_dirent_get_data_len(de, rec_len);
- return ext4_dir_rec_len(de->name_len + dirdata, dir);
+ return ext4_dirent_rec_len(de->name_len + dirdata, dir);
}
extern const struct iomap_ops ext4_iomap_ops;
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 8045e4ff270c..5b3faacdf143 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -977,7 +977,7 @@ static int ext4_add_dirent_to_inline(handle_t *handle,
struct ext4_dir_entry_2 *de;
err = ext4_find_dest_de(dir, iloc->bh, inline_start,
- inline_size, fname, &de);
+ inline_size, fname, &de, 0);
if (err)
return err;
@@ -1055,7 +1055,7 @@ static int ext4_update_inline_dir(handle_t *handle, struct inode *dir,
int old_size = EXT4_I(dir)->i_inline_size - EXT4_MIN_INLINE_DATA_SIZE;
int new_size = get_max_inline_xattr_value_size(dir, iloc);
- if (new_size - old_size <= ext4_dir_rec_len(1, NULL))
+ if (new_size - old_size <= ext4_dirent_rec_len(1, NULL))
return -ENOSPC;
ret = ext4_update_inline_data(handle, dir,
@@ -1309,7 +1309,7 @@ int ext4_inlinedir_to_tree(struct file *dir_file,
fake.name_len = 1;
memcpy(fake.name, ".", 2);
fake.rec_len = ext4_rec_len_to_disk(
- ext4_dir_rec_len(fake.name_len, NULL),
+ ext4_dirent_rec_len(fake.name_len, NULL),
inline_size);
ext4_set_de_type(inode->i_sb, &fake, S_IFDIR);
de = &fake;
@@ -1319,7 +1319,7 @@ int ext4_inlinedir_to_tree(struct file *dir_file,
fake.name_len = 2;
memcpy(fake.name, "..", 3);
fake.rec_len = ext4_rec_len_to_disk(
- ext4_dir_rec_len(fake.name_len, NULL),
+ ext4_dirent_rec_len(fake.name_len, NULL),
inline_size);
ext4_set_de_type(inode->i_sb, &fake, S_IFDIR);
de = &fake;
@@ -1427,8 +1427,8 @@ int ext4_read_inline_dir(struct file *file,
* So we will use extra_offset and extra_size to indicate them
* during the inline dir iteration.
*/
- dotdot_offset = ext4_dir_rec_len(1, NULL);
- dotdot_size = dotdot_offset + ext4_dir_rec_len(2, NULL);
+ dotdot_offset = ext4_dirent_rec_len(1, NULL);
+ dotdot_size = dotdot_offset + ext4_dirent_rec_len(2, NULL);
extra_offset = dotdot_size - EXT4_INLINE_DOTDOT_SIZE;
extra_size = extra_offset + inline_size;
@@ -1463,7 +1463,7 @@ int ext4_read_inline_dir(struct file *file,
* failure will be detected in the
* dirent test below. */
if (ext4_rec_len_from_disk(de->rec_len, extra_size)
- < ext4_dir_rec_len(1, NULL))
+ < ext4_dirent_rec_len(1, NULL))
break;
i += ext4_rec_len_from_disk(de->rec_len,
extra_size);
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index e2dda8dee77c..73c8f1b399ef 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -527,13 +527,21 @@ ext4_next_entry(struct ext4_dir_entry_2 *p, unsigned long blocksize)
* Future: use high four bits of block for coalesce-on-delete flags
* Mask them off for now.
*/
-static struct dx_root_info *dx_get_dx_info(void *de_buf)
+static struct dx_root_info *dx_get_dx_info(struct inode *dir, void *de_buf)
{
- /* get dotdot first */
- de_buf = de_buf + ext4_dir_rec_len(1, NULL);
+ unsigned int blocksize = dir->i_sb->s_blocksize;
+ void *base = de_buf;
+
+ /* get dotdot first; '.' and '..' never carry the casefold+fscrypt
+ * hash, so pass NULL for dir regardless of the directory's flags */
+ de_buf += ext4_dir_entry_len(de_buf, blocksize, NULL);
/* dx root info is after dotdot entry */
- de_buf = de_buf + ext4_dir_rec_len(2, NULL);
+ de_buf += ext4_dir_entry_len(de_buf, blocksize, NULL);
+
+ if (de_buf < base || (char *)de_buf - (char *)base +
+ sizeof(struct dx_root_info) > blocksize)
+ return ERR_PTR(-EFSCORRUPTED);
return (struct dx_root_info *)de_buf;
}
@@ -584,7 +592,9 @@ static inline unsigned dx_root_limit(struct inode *dir,
struct dx_root_info *info;
unsigned int entry_space;
- info = dx_get_dx_info(dot_de);
+ info = dx_get_dx_info(dir, dot_de);
+ if (IS_ERR(info))
+ return 0;
entry_space = dir->i_sb->s_blocksize - ((char *)info - (char *)dot_de) -
info->info_length;
@@ -596,7 +606,7 @@ static inline unsigned dx_root_limit(struct inode *dir,
static inline unsigned dx_node_limit(struct inode *dir)
{
unsigned int entry_space = dir->i_sb->s_blocksize -
- ext4_dir_rec_len(0, dir);
+ ext4_dirent_rec_len(0, dir);
if (ext4_has_feature_metadata_csum(dir->i_sb))
entry_space -= sizeof(struct dx_tail);
@@ -800,7 +810,9 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
if (IS_ERR(frame->bh))
return (struct dx_frame *) frame->bh;
- info = dx_get_dx_info((struct ext4_dir_entry_2 *)frame->bh->b_data);
+ info = dx_get_dx_info(dir, (struct ext4_dir_entry_2 *)frame->bh->b_data);
+ if (IS_ERR(info))
+ goto fail;
if (info->hash_version != DX_HASH_TEA &&
info->hash_version != DX_HASH_HALF_MD4 &&
info->hash_version != DX_HASH_LEGACY &&
@@ -945,7 +957,7 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
return ret_err;
}
-static void dx_release(struct dx_frame *frames)
+static void dx_release(struct inode *dir, struct dx_frame *frames)
{
struct dx_root_info *info;
int i;
@@ -954,7 +966,9 @@ static void dx_release(struct dx_frame *frames)
if (frames[0].bh == NULL)
return;
- info = dx_get_dx_info((struct ext4_dir_entry_2 *)frames[0].bh->b_data);
+ info = dx_get_dx_info(dir, (struct ext4_dir_entry_2 *)frames[0].bh->b_data);
+ if (IS_ERR(info))
+ return;
/* save local copy, "info" may be freed after brelse() */
indirect_levels = info->indirect_levels;
for (i = 0; i <= indirect_levels; i++) {
@@ -1066,7 +1080,7 @@ static int htree_dirblock_to_tree(struct file *dir_file,
/* csum entries are not larger in the casefolded encrypted case */
top = (struct ext4_dir_entry_2 *) ((char *) de +
dir->i_sb->s_blocksize -
- ext4_dir_rec_len(0,
+ ext4_dirent_rec_len(0,
csum ? NULL : dir));
/* Check if the directory is encrypted */
if (IS_ENCRYPTED(dir)) {
@@ -1260,12 +1274,12 @@ int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
(count && ((hashval & 1) == 0)))
break;
}
- dx_release(frames);
+ dx_release(dir, frames);
dxtrace(printk(KERN_DEBUG "Fill tree: returned %d entries, "
"next hash: %x\n", count, *next_hash));
return count;
errout:
- dx_release(frames);
+ dx_release(dir, frames);
return (err);
}
@@ -1763,7 +1777,7 @@ static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
errout:
dxtrace(printk(KERN_DEBUG "%s not found\n", fname->usr_fname->name));
success:
- dx_release(frames);
+ dx_release(dir, frames);
return bh;
}
@@ -1860,7 +1874,7 @@ dx_move_dirents(struct inode *dir, char *from, char *to,
while (count--) {
struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
(from + (map->offs<<2));
- rec_len = ext4_dir_rec_len(de->name_len, dir);
+ rec_len = ext4_dir_entry_len(de, blocksize, dir);
memcpy (to, de, rec_len);
((struct ext4_dir_entry_2 *) to)->rec_len =
@@ -1893,7 +1907,7 @@ static struct ext4_dir_entry_2 *dx_pack_dirents(struct inode *dir, char *base,
while ((char*)de < base + blocksize) {
next = ext4_next_entry(de, blocksize);
if (de->inode && de->name_len) {
- rec_len = ext4_dir_rec_len(de->name_len, dir);
+ rec_len = ext4_dir_entry_len(de, blocksize, dir);
if (de > to)
memmove(to, de, rec_len);
to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
@@ -2045,10 +2059,11 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
int ext4_find_dest_de(struct inode *dir, struct buffer_head *bh,
void *buf, int buf_size,
struct ext4_filename *fname,
- struct ext4_dir_entry_2 **dest_de)
+ struct ext4_dir_entry_2 **dest_de,
+ int dlen)
{
struct ext4_dir_entry_2 *de;
- unsigned short reclen = ext4_dir_rec_len(fname_len(fname), dir);
+ unsigned short reclen = ext4_dirent_rec_len(fname_len(fname) + dlen, dir);
int nlen, rlen;
unsigned int offset = 0;
char *top;
@@ -2061,7 +2076,7 @@ int ext4_find_dest_de(struct inode *dir, struct buffer_head *bh,
return -EFSCORRUPTED;
if (ext4_match(dir, fname, de))
return -EEXIST;
- nlen = ext4_dir_rec_len(de->name_len, dir);
+ nlen = ext4_dir_entry_len(de, buf_size, dir);
rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
if ((de->inode ? rlen - nlen : rlen) >= reclen)
break;
@@ -2084,7 +2099,7 @@ void ext4_insert_dentry(struct inode *dir,
int nlen, rlen;
- nlen = ext4_dir_rec_len(de->name_len, dir);
+ nlen = ext4_dir_entry_len(de, buf_size, dir);
rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
if (de->inode) {
struct ext4_dir_entry_2 *de1 =
@@ -2122,14 +2137,18 @@ static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
{
unsigned int blocksize = dir->i_sb->s_blocksize;
int csum_size = 0;
- int err, err2;
+ int err, err2, dlen = 0;
+ unsigned char *data = NULL;
+ /* Deliver data in any appropriate way here. Now it is NULL */
if (ext4_has_feature_metadata_csum(inode->i_sb))
csum_size = sizeof(struct ext4_dir_entry_tail);
if (!de) {
+ if (data)
+ dlen = (*data) + 1;
err = ext4_find_dest_de(dir, bh, bh->b_data,
- blocksize - csum_size, fname, &de);
+ blocksize - csum_size, fname, &de, dlen);
if (err)
return err;
}
@@ -2284,7 +2303,12 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
blocksize);
/* initialize hashing info */
- dx_info = dx_get_dx_info(dot_de);
+ dx_info = dx_get_dx_info(dir, dot_de);
+ if (IS_ERR(dx_info)) {
+ brelse(bh2);
+ brelse(bh);
+ return PTR_ERR(dx_info);
+ }
memset(dx_info, 0, sizeof(*dx_info));
dx_info->info_length = sizeof(*dx_info);
if (ext4_hash_in_dirent(dir))
@@ -2342,7 +2366,7 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
*/
if (retval)
ext4_mark_inode_dirty(handle, dir);
- dx_release(frames);
+ dx_release(dir, frames);
brelse(bh2);
return retval;
}
@@ -2617,8 +2641,13 @@ static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
/* Set up root */
dx_set_count(entries, 1);
dx_set_block(entries + 0, newblock);
- info = dx_get_dx_info((struct ext4_dir_entry_2 *)
+ info = dx_get_dx_info(dir, (struct ext4_dir_entry_2 *)
frames[0].bh->b_data);
+ if (IS_ERR(info)) {
+ err = PTR_ERR(info);
+ brelse(bh2);
+ goto journal_error;
+ }
info->indirect_levels += 1;
dxtrace(printk(KERN_DEBUG
"Creating %d level index...\n",
@@ -2646,7 +2675,7 @@ static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
ext4_std_error(dir->i_sb, err); /* this is a no-op if err == 0 */
cleanup:
brelse(bh);
- dx_release(frames);
+ dx_release(dir, frames);
/* @restart is true means htree-path has been changed, we need to
* repeat dx_probe() to find out valid htree-path
*/
@@ -2938,7 +2967,7 @@ int ext4_init_dirblock(handle_t *handle, struct inode *inode,
de->inode = cpu_to_le32(inode->i_ino);
de->name_len = 1;
- de->rec_len = ext4_rec_len_to_disk(ext4_dir_rec_len(de->name_len, NULL),
+ de->rec_len = ext4_rec_len_to_disk(ext4_dirent_rec_len(de->name_len, NULL),
blocksize);
memcpy(de->name, ".", 2);
ext4_set_de_type(inode->i_sb, de, S_IFDIR);
@@ -2950,7 +2979,7 @@ int ext4_init_dirblock(handle_t *handle, struct inode *inode,
ext4_set_de_type(inode->i_sb, de, S_IFDIR);
if (inline_buf) {
de->rec_len = ext4_rec_len_to_disk(
- ext4_dir_rec_len(de->name_len, NULL),
+ ext4_dirent_rec_len(de->name_len, NULL),
blocksize);
de = ext4_next_entry(de, blocksize);
header_size = (char *)de - bh->b_data;
@@ -2959,7 +2988,7 @@ int ext4_init_dirblock(handle_t *handle, struct inode *inode,
blocksize - csum_size);
} else {
de->rec_len = ext4_rec_len_to_disk(blocksize -
- (csum_size + ext4_dir_rec_len(1, NULL)),
+ (csum_size + ext4_dirent_rec_len(1, NULL)),
blocksize);
}
@@ -3082,8 +3111,8 @@ bool ext4_empty_dir(struct inode *inode)
}
sb = inode->i_sb;
- if (inode->i_size < ext4_dir_rec_len(1, NULL) +
- ext4_dir_rec_len(2, NULL)) {
+ if (inode->i_size < ext4_dirent_rec_len(1, NULL) +
+ ext4_dirent_rec_len(2, NULL)) {
EXT4_ERROR_INODE(inode, "invalid size");
return false;
}
--
2.43.7
^ permalink raw reply related
* [PATCH v4 07/11] ext4: add ext4_dir_entry_len() and harden dirdata parsing
From: Artem Blagodarenko @ 2026-06-24 13:36 UTC (permalink / raw)
To: linux-ext4; +Cc: adilger.kernel, Artem Blagodarenko, Andreas Dilger
In-Reply-To: <20260624133642.18438-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Introduce ext4_dir_entry_len() helper to compute the required
rec_len for a directory entry, taking into account dirdata and
casefold+fscrypt hash space.
Convert ext4_dirent_get_data_len() to take the decoded rec_len
as an argument and add bounds checking when walking dirdata
extensions to avoid overruns on malformed entries.
Update dx_root_limit() to use ext4_dir_entry_len() instead of
open-coded ext4_dir_rec_len() for '.' and '..' entries.
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
---
fs/ext4/ext4.h | 51 ++++++++++++++++++++++++++++++++++++++++++++++---
fs/ext4/namei.c | 23 ++++++++++++++--------
2 files changed, 63 insertions(+), 11 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 2f29f50a12ac..a369a0cd04bc 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -4075,6 +4075,7 @@ static inline bool ext4_dir_entry_is_tail(struct ext4_dir_entry_2 *de)
/*
* ext4_dirent_get_data_len() - Compute the total dirdata length for an entry.
* @de: directory entry
+ * @rec_len: the record length of the directory entry (decoded)
*
* Computes the length of optional data stored after the filename (and its
* implicit NUL terminator). Each extension is indicated by a bit in the
@@ -4083,22 +4084,41 @@ static inline bool ext4_dir_entry_is_tail(struct ext4_dir_entry_2 *de)
*
* Returns 0 for tail entries and for entries with no dirdata.
*/
-static inline int ext4_dirent_get_data_len(struct ext4_dir_entry_2 *de)
+static inline int ext4_dirent_get_data_len(struct ext4_dir_entry_2 *de,
+ unsigned int rec_len)
{
__u8 extra_data_flags;
struct ext4_dirent_data_header *ddh;
int dlen = 0;
+ unsigned int offset;
if (ext4_dir_entry_is_tail(de))
return 0;
extra_data_flags = (de->file_type & ~EXT4_FT_MASK) >> 4;
- ddh = (struct ext4_dirent_data_header *)(de->name + de->name_len +
- 1 /* NUL terminator */);
+ /* offset from start of entry to after filename + NUL */
+ offset = EXT4_BASE_DIR_LEN + de->name_len + 1;
+ /* bounds check: ensure we start reading within the entry */
+ if (offset >= rec_len)
+ return 0;
+
+ ddh = (struct ext4_dirent_data_header *)((char *)de + offset);
+
while (extra_data_flags) {
if (extra_data_flags & 1) {
+ /* bounds check before reading ddh_length */
+ if (offset + sizeof(*ddh) >
+ rec_len)
+ return dlen;
+
+ /* validate ddh_length is reasonable */
+ if (ddh->ddh_length == 0 || ddh->ddh_length >
+ rec_len - offset)
+ return dlen;
+
dlen += ddh->ddh_length + (dlen == 0);
+ offset += ddh->ddh_length;
ddh = ext4_dirdata_next(ddh);
}
extra_data_flags >>= 1;
@@ -4106,6 +4126,31 @@ static inline int ext4_dirent_get_data_len(struct ext4_dir_entry_2 *de)
return dlen;
}
+/*
+ * ext4_dir_entry_len() - Compute the required rec_len for a directory entry.
+ * @de: directory entry (used to read name_len and any dirdata length)
+ * @blocksize: size of the buffer @de lives in (the real directory block
+ * size, or the smaller inline-data buffer size for inline
+ * directories) -- used only to decode @de->rec_len's "0/65535
+ * means rest of buffer" sentinel correctly.
+ * @dir: directory inode (may be NULL for '.' and '..' entries, which
+ * never carry the casefold+fscrypt hash regardless of the
+ * directory's feature flags)
+ *
+ * Returns the minimum record length needed to hold @de, rounded up to the
+ * directory alignment and including room for the casefold+fscrypt hash if
+ * the directory requires it.
+ */
+static inline unsigned int ext4_dir_entry_len(struct ext4_dir_entry_2 *de,
+ unsigned int blocksize,
+ const struct inode *dir)
+{
+ unsigned int rec_len = ext4_rec_len_from_disk(de->rec_len, blocksize);
+ unsigned int dirdata = ext4_dirent_get_data_len(de, rec_len);
+
+ return ext4_dir_rec_len(de->name_len + dirdata, dir);
+}
+
extern const struct iomap_ops ext4_iomap_ops;
extern const struct iomap_ops ext4_iomap_report_ops;
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 61410fa0effa..e2dda8dee77c 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -578,11 +578,15 @@ static inline void dx_set_limit(struct dx_entry *entries, unsigned value)
((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
}
-static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
+static inline unsigned dx_root_limit(struct inode *dir,
+ struct ext4_dir_entry_2 *dot_de)
{
- unsigned int entry_space = dir->i_sb->s_blocksize -
- ext4_dir_rec_len(1, NULL) -
- ext4_dir_rec_len(2, NULL) - infosize;
+ struct dx_root_info *info;
+ unsigned int entry_space;
+
+ info = dx_get_dx_info(dot_de);
+ entry_space = dir->i_sb->s_blocksize - ((char *)info - (char *)dot_de) -
+ info->info_length;
if (ext4_has_feature_metadata_csum(dir->i_sb))
entry_space -= sizeof(struct dx_tail);
@@ -858,10 +862,13 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
entries = (struct dx_entry *)(((char *)info) + info->info_length);
- if (dx_get_limit(entries) != dx_root_limit(dir, info->info_length)) {
+ if (dx_get_limit(entries) !=
+ dx_root_limit(dir, (struct ext4_dir_entry_2 *)frame->bh->b_data)) {
ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
dx_get_limit(entries),
- dx_root_limit(dir, info->info_length));
+ dx_root_limit(dir,
+ (struct ext4_dir_entry_2 *)frame->bh->b_data
+ ));
goto fail;
}
@@ -2286,10 +2293,10 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
dx_info->hash_version =
EXT4_SB(dir->i_sb)->s_def_hash_version;
- entries = (void *)dx_info + sizeof(*dx_info);
+ entries = (void *)dx_info + dx_info->info_length;
dx_set_block(entries, 1);
dx_set_count(entries, 1);
- dx_set_limit(entries, dx_root_limit(dir, sizeof(*dx_info)));
+ dx_set_limit(entries, dx_root_limit(dir, dot_de));
/* Initialize as for dx_probe */
fname->hinfo.hash_version = dx_info->hash_version;
--
2.43.7
^ permalink raw reply related
* [PATCH v4 06/11] ext4: preserve dirdata bits in get_dtype()
From: Artem Blagodarenko @ 2026-06-24 13:36 UTC (permalink / raw)
To: linux-ext4; +Cc: adilger.kernel, Artem Blagodarenko, Andreas Dilger
In-Reply-To: <20260624133642.18438-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Mask the filetype with EXT4_FT_MASK when indexing
ext4_filetype_table[] to avoid using dirdata bits as an index.
Preserve the extra bits
stored in the upper part of filetype and propagate them to the
returned dtype value.
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
---
fs/ext4/ext4.h | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 98603aa44693..2f29f50a12ac 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3046,12 +3046,15 @@ static const unsigned char ext4_filetype_table[] = {
DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
};
-static inline unsigned char get_dtype(struct super_block *sb, int filetype)
+static inline unsigned char get_dtype(struct super_block *sb, int filetype)
{
- if (!ext4_has_feature_filetype(sb) || filetype >= EXT4_FT_MAX)
+ unsigned char fl_index = filetype & EXT4_FT_MASK;
+
+ if (!ext4_has_feature_filetype(sb) || fl_index >= EXT4_FT_MAX)
return DT_UNKNOWN;
- return ext4_filetype_table[filetype];
+ return (ext4_filetype_table[fl_index]) |
+ (filetype & ~EXT4_FT_MASK);
}
extern int ext4_check_all_de(struct inode *dir, struct buffer_head *bh,
void *buf, int buf_size);
--
2.43.7
^ permalink raw reply related
* [PATCH v4 05/11] ext4: add dirdata format definitions and access helpers
From: Artem Blagodarenko @ 2026-06-24 13:36 UTC (permalink / raw)
To: linux-ext4
Cc: adilger.kernel, Artem Blagodarenko, Pravin Shelar, Andreas Dilger
In-Reply-To: <20260624133642.18438-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Define the on-disk format for ext4 directory entry extension data.
The upper four bits of de->file_type indicate the presence of
optional data stored after the filename NUL terminator. This patch
defines flags for LUFID, 64-bit inode numbers, and casefold hash
data stored in that area.
Add struct ext4_dirent_data_header to describe variable-length
extension records and struct ext4_dirent_hash for hash storage used
by casefold and fscrypt.
Provide ext4_dirdata_next() to advance to the next extension record
and ext4_dirent_get_data_len() to compute the total extension data
length associated with a directory entry.
No functional changes.
Signed-off-by: Pravin Shelar <pravin.shelar@sun.com>
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Reviewed-by: Andreas Dilger <adilger@diliger.ca>
---
fs/ext4/ext4.h | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 83 insertions(+)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 9400bc2858a5..98603aa44693 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2556,6 +2556,49 @@ struct ext4_dir_entry_tail {
#define EXT4_FT_SYMLINK 7
#define EXT4_FT_MAX 8
+#define EXT4_FT_MASK 0xf
+
+#if EXT4_FT_MAX > EXT4_FT_MASK
+#error "conflicting EXT4_FT_MAX and EXT4_FT_MASK"
+#endif
+
+/*
+ * d_type has 4 unused bits, so it can hold four types of data. These different
+ * types of data (e.g. fscypt hash, high 32 bits of 64-bit inode number) can be
+ * stored, in flag order, after file-name in ext4 dirent.
+ *
+ * These flags are added to d_type if ext4 dirent has extra data after
+ * filename. This data length is variable and length is stored in first byte
+ * of data. Data starts after filename NUL byte.
+ */
+#define EXT4_DIRENT_LUFID 0x10
+#define EXT4_DIRENT_INO64 0x20
+#define EXT4_DIRENT_CFHASH 0x40
+
+struct ext4_fid {
+ char fid[16]; /* 128-bit unique file identifier */
+};
+
+struct ext4_dirent_data_header {
+ /* length of this header + the whole data blob */
+ __u8 ddh_length;
+} __packed;
+
+struct ext4_dirent_fid {
+ struct ext4_dirent_data_header df_header;
+ struct ext4_fid df_fid[];
+};
+
+#define EXT4_LUFID_MAGIC 0xAD200907UL
+struct ext4_dentry_param {
+ __u32 edp_magic; /* EXT4_LUFID_MAGIC */
+ struct ext4_dirent_fid edp_dfid;
+};
+
+struct ext4_dirent_hash {
+ struct ext4_dirent_data_header dh_header;
+ struct ext4_dir_entry_hash dh_hash;
+} __packed;
#define EXT4_FT_DIR_CSUM 0xDE
@@ -4004,6 +4047,12 @@ static inline void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end)
io_end->flag &= ~EXT4_IO_END_UNWRITTEN;
}
+/*
+ * Advance to the next dirdata record header starting from @ddh.
+ */
+#define ext4_dirdata_next(ddh) \
+ ((struct ext4_dirent_data_header *)((char *)(ddh) + (ddh)->ddh_length))
+
/*
* ext4_dir_entry_is_tail() - Check if a directory entry is a tail entry.
* @de: directory entry to check
@@ -4020,6 +4069,40 @@ static inline bool ext4_dir_entry_is_tail(struct ext4_dir_entry_2 *de)
t->det_reserved_ft == EXT4_FT_DIR_CSUM;
}
+/*
+ * ext4_dirent_get_data_len() - Compute the total dirdata length for an entry.
+ * @de: directory entry
+ *
+ * Computes the length of optional data stored after the filename (and its
+ * implicit NUL terminator). Each extension is indicated by a bit in the
+ * high 4 bits of de->file_type; the first byte of each extension is its
+ * length (including that length byte itself).
+ *
+ * Returns 0 for tail entries and for entries with no dirdata.
+ */
+static inline int ext4_dirent_get_data_len(struct ext4_dir_entry_2 *de)
+{
+ __u8 extra_data_flags;
+ struct ext4_dirent_data_header *ddh;
+ int dlen = 0;
+
+ if (ext4_dir_entry_is_tail(de))
+ return 0;
+
+ extra_data_flags = (de->file_type & ~EXT4_FT_MASK) >> 4;
+ ddh = (struct ext4_dirent_data_header *)(de->name + de->name_len +
+ 1 /* NUL terminator */);
+
+ while (extra_data_flags) {
+ if (extra_data_flags & 1) {
+ dlen += ddh->ddh_length + (dlen == 0);
+ ddh = ext4_dirdata_next(ddh);
+ }
+ extra_data_flags >>= 1;
+ }
+ return dlen;
+}
+
extern const struct iomap_ops ext4_iomap_ops;
extern const struct iomap_ops ext4_iomap_report_ops;
--
2.43.7
^ permalink raw reply related
* [PATCH v4 04/11] ext4: refactor dx_root to support variable dirent sizes
From: Artem Blagodarenko @ 2026-06-24 13:36 UTC (permalink / raw)
To: linux-ext4
Cc: adilger.kernel, Artem Blagodarenko, Pravin Shelar, Andreas Dilger
In-Reply-To: <20260624133642.18438-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Split monolithic definition of dx_root struct to separate dx_root_info
from fake struct ext4_dir_entry2 for improved code readability.
This allows "." and ".." dirents to have different sizes if necessary,
since we can't assume the rec_len 12 if dx_root dirents have dirdata.
Adds dx_get_dx_info() accessor instead of complex typecast at callers.
Does not change any functionality.
Signed-off-by: Pravin Shelar <pravin.shelar@sun.com>
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
---
fs/ext4/namei.c | 145 +++++++++++++++++++++++-------------------------
1 file changed, 70 insertions(+), 75 deletions(-)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 2fc14332fab7..61410fa0effa 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -244,22 +244,13 @@ struct dx_entry
* hash version mod 4 should never be 0. Sincerely, the paranoia department.
*/
-struct dx_root
+struct dx_root_info
{
- struct fake_dirent dot;
- char dot_name[4];
- struct fake_dirent dotdot;
- char dotdot_name[4];
- struct dx_root_info
- {
- __le32 reserved_zero;
- u8 hash_version;
- u8 info_length; /* 8 */
- u8 indirect_levels;
- u8 unused_flags;
- }
- info;
- struct dx_entry entries[];
+ __le32 reserved_zero;
+ u8 hash_version;
+ u8 info_length; /* 8 */
+ u8 indirect_levels;
+ u8 unused_flags;
};
struct dx_node
@@ -536,6 +527,16 @@ ext4_next_entry(struct ext4_dir_entry_2 *p, unsigned long blocksize)
* Future: use high four bits of block for coalesce-on-delete flags
* Mask them off for now.
*/
+static struct dx_root_info *dx_get_dx_info(void *de_buf)
+{
+ /* get dotdot first */
+ de_buf = de_buf + ext4_dir_rec_len(1, NULL);
+
+ /* dx root info is after dotdot entry */
+ de_buf = de_buf + ext4_dir_rec_len(2, NULL);
+
+ return (struct dx_root_info *)de_buf;
+}
static inline ext4_lblk_t dx_get_block(struct dx_entry *entry)
{
@@ -783,7 +784,7 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
{
unsigned count, indirect, level, i;
struct dx_entry *at, *entries, *p, *q, *m;
- struct dx_root *root;
+ struct dx_root_info *info;
struct dx_frame *frame = frame_in;
struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
u32 hash;
@@ -795,23 +796,24 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
if (IS_ERR(frame->bh))
return (struct dx_frame *) frame->bh;
- root = (struct dx_root *) frame->bh->b_data;
- if (root->info.hash_version != DX_HASH_TEA &&
- root->info.hash_version != DX_HASH_HALF_MD4 &&
- root->info.hash_version != DX_HASH_LEGACY &&
- root->info.hash_version != DX_HASH_SIPHASH) {
- ext4_warning_inode(dir, "Unrecognised inode hash code %u",
- root->info.hash_version);
+ info = dx_get_dx_info((struct ext4_dir_entry_2 *)frame->bh->b_data);
+ if (info->hash_version != DX_HASH_TEA &&
+ info->hash_version != DX_HASH_HALF_MD4 &&
+ info->hash_version != DX_HASH_LEGACY &&
+ info->hash_version != DX_HASH_SIPHASH) {
+ ext4_warning(dir->i_sb,
+ "Unrecognised inode hash code %d for directory #%llu",
+ info->hash_version, dir->i_ino);
goto fail;
}
if (ext4_hash_in_dirent(dir)) {
- if (root->info.hash_version != DX_HASH_SIPHASH) {
+ if (info->hash_version != DX_HASH_SIPHASH) {
ext4_warning_inode(dir,
"Hash in dirent, but hash is not SIPHASH");
goto fail;
}
} else {
- if (root->info.hash_version == DX_HASH_SIPHASH) {
+ if (info->hash_version == DX_HASH_SIPHASH) {
ext4_warning_inode(dir,
"Hash code is SIPHASH, but hash not in dirent");
goto fail;
@@ -819,7 +821,7 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
}
if (fname)
hinfo = &fname->hinfo;
- hinfo->hash_version = root->info.hash_version;
+ hinfo->hash_version = info->hash_version;
if (hinfo->hash_version <= DX_HASH_TEA)
hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
@@ -835,13 +837,13 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
}
hash = hinfo->hash;
- if (root->info.unused_flags & 1) {
+ if (info->unused_flags & 1) {
ext4_warning_inode(dir, "Unimplemented hash flags: %#06x",
- root->info.unused_flags);
+ info->unused_flags);
goto fail;
}
- indirect = root->info.indirect_levels;
+ indirect = info->indirect_levels;
if (indirect >= ext4_dir_htree_level(dir->i_sb)) {
ext4_warning(dir->i_sb,
"Directory (ino: %llu) htree depth %#06x exceed"
@@ -854,14 +856,12 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
goto fail;
}
- entries = (struct dx_entry *)(((char *)&root->info) +
- root->info.info_length);
+ entries = (struct dx_entry *)(((char *)info) + info->info_length);
- if (dx_get_limit(entries) != dx_root_limit(dir,
- root->info.info_length)) {
+ if (dx_get_limit(entries) != dx_root_limit(dir, info->info_length)) {
ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
dx_get_limit(entries),
- dx_root_limit(dir, root->info.info_length));
+ dx_root_limit(dir, info->info_length));
goto fail;
}
@@ -947,7 +947,7 @@ static void dx_release(struct dx_frame *frames)
if (frames[0].bh == NULL)
return;
- info = &((struct dx_root *)frames[0].bh->b_data)->info;
+ info = dx_get_dx_info((struct ext4_dir_entry_2 *)frames[0].bh->b_data);
/* save local copy, "info" may be freed after brelse() */
indirect_levels = info->indirect_levels;
for (i = 0; i <= indirect_levels; i++) {
@@ -2159,44 +2159,38 @@ static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
return err ? err : err2;
}
-static bool ext4_check_dx_root(struct inode *dir, struct dx_root *root)
+static bool ext4_check_dx_root(struct inode *dir,
+ struct ext4_dir_entry_2 *dot_de,
+ struct ext4_dir_entry_2 *dotdot_de,
+ struct ext4_dir_entry_2 **entry)
{
- struct fake_dirent *fde;
const char *error_msg;
- unsigned int rlen;
unsigned int blocksize = dir->i_sb->s_blocksize;
- char *blockend = (char *)root + dir->i_sb->s_blocksize;
+ struct ext4_dir_entry_2 *de = NULL;
- fde = &root->dot;
- if (unlikely(fde->name_len != 1)) {
+ if (unlikely(dot_de->name_len != 1)) {
error_msg = "invalid name_len for '.'";
goto corrupted;
}
- if (unlikely(strncmp(root->dot_name, ".", fde->name_len))) {
+ if (unlikely(strncmp(dot_de->name, ".", dot_de->name_len))) {
error_msg = "invalid name for '.'";
goto corrupted;
}
- rlen = ext4_rec_len_from_disk(fde->rec_len, blocksize);
- if (unlikely((char *)fde + rlen >= blockend)) {
- error_msg = "invalid rec_len for '.'";
- goto corrupted;
- }
- fde = &root->dotdot;
- if (unlikely(fde->name_len != 2)) {
+ if (unlikely(dotdot_de->name_len != 2)) {
error_msg = "invalid name_len for '..'";
goto corrupted;
}
- if (unlikely(strncmp(root->dotdot_name, "..", fde->name_len))) {
+ if (unlikely(strncmp(dotdot_de->name, "..", dotdot_de->name_len))) {
error_msg = "invalid name for '..'";
goto corrupted;
}
- rlen = ext4_rec_len_from_disk(fde->rec_len, blocksize);
- if (unlikely((char *)fde + rlen >= blockend)) {
+ de = ext4_next_entry(dotdot_de, blocksize);
+ if ((char *)de >= (((char *)dot_de) + blocksize)) {
error_msg = "invalid rec_len for '..'";
goto corrupted;
}
-
+ *entry = de;
return true;
corrupted:
@@ -2214,16 +2208,15 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
struct inode *inode, struct buffer_head *bh)
{
struct buffer_head *bh2;
- struct dx_root *root;
struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
struct dx_entry *entries;
- struct ext4_dir_entry_2 *de, *de2;
+ struct ext4_dir_entry_2 *de, *de2, *dot_de, *dotdot_de;
char *data2, *top;
unsigned len;
int retval;
unsigned blocksize;
ext4_lblk_t block;
- struct fake_dirent *fde;
+ struct dx_root_info *dx_info;
int csum_size = 0;
if (ext4_has_feature_metadata_csum(inode->i_sb))
@@ -2240,17 +2233,15 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
return retval;
}
- root = (struct dx_root *) bh->b_data;
- if (!ext4_check_dx_root(dir, root)) {
+ dot_de = (struct ext4_dir_entry_2 *)bh->b_data;
+ dotdot_de = ext4_next_entry(dot_de, blocksize);
+ if (!ext4_check_dx_root(dir, dot_de, dotdot_de, &de)) {
brelse(bh);
return -EFSCORRUPTED;
}
/* The 0th block becomes the root, move the dirents out */
- fde = &root->dotdot;
- de = (struct ext4_dir_entry_2 *)((char *)fde +
- ext4_rec_len_from_disk(fde->rec_len, blocksize));
- len = ((char *) root) + (blocksize - csum_size) - (char *) de;
+ len = ((char *)dot_de) + (blocksize - csum_size) - (char *)de;
/* Allocate new block for the 0th block's dirents */
bh2 = ext4_append(handle, dir, &block);
@@ -2281,24 +2272,27 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
ext4_initialize_dirent_tail(bh2, blocksize);
/* Initialize the root; the dot dirents already exist */
- de = (struct ext4_dir_entry_2 *) (&root->dotdot);
- de->rec_len = ext4_rec_len_to_disk(
- blocksize - ext4_dir_rec_len(2, NULL), blocksize);
- memset (&root->info, 0, sizeof(root->info));
- root->info.info_length = sizeof(root->info);
+ dotdot_de->rec_len =
+ ext4_rec_len_to_disk(blocksize - le16_to_cpu(dot_de->rec_len),
+ blocksize);
+
+ /* initialize hashing info */
+ dx_info = dx_get_dx_info(dot_de);
+ memset(dx_info, 0, sizeof(*dx_info));
+ dx_info->info_length = sizeof(*dx_info);
if (ext4_hash_in_dirent(dir))
- root->info.hash_version = DX_HASH_SIPHASH;
+ dx_info->hash_version = DX_HASH_SIPHASH;
else
- root->info.hash_version =
+ dx_info->hash_version =
EXT4_SB(dir->i_sb)->s_def_hash_version;
- entries = root->entries;
+ entries = (void *)dx_info + sizeof(*dx_info);
dx_set_block(entries, 1);
dx_set_count(entries, 1);
- dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
+ dx_set_limit(entries, dx_root_limit(dir, sizeof(*dx_info)));
/* Initialize as for dx_probe */
- fname->hinfo.hash_version = root->info.hash_version;
+ fname->hinfo.hash_version = dx_info->hash_version;
if (fname->hinfo.hash_version <= DX_HASH_TEA)
fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
@@ -2608,7 +2602,7 @@ static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
if (restart || err)
goto journal_error;
} else {
- struct dx_root *dxroot;
+ struct dx_root_info *info;
memcpy((char *) entries2, (char *) entries,
icount * sizeof(struct dx_entry));
dx_set_limit(entries2, dx_node_limit(dir));
@@ -2616,8 +2610,9 @@ static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
/* Set up root */
dx_set_count(entries, 1);
dx_set_block(entries + 0, newblock);
- dxroot = (struct dx_root *)frames[0].bh->b_data;
- dxroot->info.indirect_levels += 1;
+ info = dx_get_dx_info((struct ext4_dir_entry_2 *)
+ frames[0].bh->b_data);
+ info->indirect_levels += 1;
dxtrace(printk(KERN_DEBUG
"Creating %d level index...\n",
dxroot->info.indirect_levels));
--
2.43.7
^ permalink raw reply related
* [PATCH v4 03/11] ext4: add ext4_dir_entry_is_tail()
From: Artem Blagodarenko @ 2026-06-24 13:36 UTC (permalink / raw)
To: linux-ext4; +Cc: adilger.kernel, Artem Blagodarenko, Andreas Dilger
In-Reply-To: <20260624133642.18438-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Replace open-coded checks for directory tail entries with a call
to ext4_dir_entry_is_tail(). This helper will also be used by
upcoming changes.
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
---
fs/ext4/ext4.h | 16 ++++++++++++++++
fs/ext4/namei.c | 7 +------
2 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index b37c136ea3ab..9400bc2858a5 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -4004,6 +4004,22 @@ static inline void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end)
io_end->flag &= ~EXT4_IO_END_UNWRITTEN;
}
+/*
+ * ext4_dir_entry_is_tail() - Check if a directory entry is a tail entry.
+ * @de: directory entry to check
+ *
+ * Returns true if @de is a directory block tail entry (checksum record).
+ */
+static inline bool ext4_dir_entry_is_tail(struct ext4_dir_entry_2 *de)
+{
+ struct ext4_dir_entry_tail *t = (struct ext4_dir_entry_tail *)de;
+
+ return !t->det_reserved_zero1 &&
+ le16_to_cpu(t->det_rec_len) == sizeof(*t) &&
+ !t->det_reserved_zero2 &&
+ t->det_reserved_ft == EXT4_FT_DIR_CSUM;
+}
+
extern const struct iomap_ops ext4_iomap_ops;
extern const struct iomap_ops ext4_iomap_report_ops;
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index c2f330c75c81..2fc14332fab7 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -314,7 +314,6 @@ static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
struct buffer_head *bh)
{
struct ext4_dir_entry_tail *t;
- int blocksize = EXT4_BLOCK_SIZE(inode->i_sb);
#ifdef PARANOID
struct ext4_dir_entry_2 *d, *top;
@@ -334,11 +333,7 @@ static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
t = EXT4_DIRENT_TAIL(bh->b_data, EXT4_BLOCK_SIZE(inode->i_sb));
#endif
- if (t->det_reserved_zero1 ||
- (ext4_rec_len_from_disk(t->det_rec_len, blocksize) !=
- sizeof(struct ext4_dir_entry_tail)) ||
- t->det_reserved_zero2 ||
- t->det_reserved_ft != EXT4_FT_DIR_CSUM)
+ if (!ext4_dir_entry_is_tail((struct ext4_dir_entry_2 *)t))
return NULL;
return t;
--
2.43.7
^ permalink raw reply related
* [PATCH v4 02/11] ext4: replace ext4_dir_entry with ext4_dir_entry_2
From: Artem Blagodarenko @ 2026-06-24 13:36 UTC (permalink / raw)
To: linux-ext4; +Cc: adilger.kernel, Artem Blagodarenko, Andreas Dilger
In-Reply-To: <20260624133642.18438-1-ablagodarenko@thelustrecollective.com>
From: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Replace remaining uses of struct ext4_dir_entry in namei.c
with struct ext4_dir_entry_2.
The code paths affected by this change already depend on the
filetype feature, so using struct ext4_dir_entry_2 is
appropriate and avoids mixing the two directory entry types
unnecessarily.
This change does not affect support for 16-bit rec_len.
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
---
fs/ext4/namei.c | 38 +++++++++++++++++++-------------------
1 file changed, 19 insertions(+), 19 deletions(-)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index a283e285937a..c2f330c75c81 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -102,7 +102,7 @@ static struct buffer_head *ext4_append(handle_t *handle,
}
static int ext4_dx_csum_verify(struct inode *inode,
- struct ext4_dir_entry *dirent);
+ struct ext4_dir_entry_2 *dirent);
/*
* Hints to ext4_read_dirblock regarding whether we expect a directory
@@ -128,7 +128,7 @@ static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
unsigned int line)
{
struct buffer_head *bh;
- struct ext4_dir_entry *dirent;
+ struct ext4_dir_entry_2 *dirent;
int is_dx_block = 0;
if (block >= inode->i_size >> inode->i_blkbits) {
@@ -160,7 +160,7 @@ static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
}
if (!bh)
return NULL;
- dirent = (struct ext4_dir_entry *) bh->b_data;
+ dirent = (struct ext4_dir_entry_2 *) bh->b_data;
/* Determine whether or not we have an index block */
if (is_dx(inode)) {
if (block == 0)
@@ -317,13 +317,13 @@ static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
int blocksize = EXT4_BLOCK_SIZE(inode->i_sb);
#ifdef PARANOID
- struct ext4_dir_entry *d, *top;
+ struct ext4_dir_entry_2 *d, *top;
- d = (struct ext4_dir_entry *)bh->b_data;
- top = (struct ext4_dir_entry *)(bh->b_data +
+ d = (struct ext4_dir_entry_2 *)bh->b_data;
+ top = (struct ext4_dir_entry_2 *)(bh->b_data +
(blocksize - sizeof(struct ext4_dir_entry_tail)));
while (d < top && ext4_rec_len_from_disk(d->rec_len, blocksize))
- d = (struct ext4_dir_entry *)(((void *)d) +
+ d = (struct ext4_dir_entry_2 *)(((void *)d) +
ext4_rec_len_from_disk(d->rec_len, blocksize));
if (d != top)
@@ -410,22 +410,22 @@ int ext4_handle_dirty_dirblock(handle_t *handle,
}
static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
- struct ext4_dir_entry *dirent,
+ struct ext4_dir_entry_2 *dirent,
int *offset)
{
- struct ext4_dir_entry *dp;
+ struct ext4_dir_entry_2 *de;
struct dx_root_info *root;
int count_offset;
int blocksize = EXT4_BLOCK_SIZE(inode->i_sb);
unsigned int rlen = ext4_rec_len_from_disk(dirent->rec_len, blocksize);
if (rlen == blocksize)
- count_offset = 8;
+ count_offset = sizeof(struct dx_node);
else if (rlen == 12) {
- dp = (struct ext4_dir_entry *)(((void *)dirent) + 12);
- if (ext4_rec_len_from_disk(dp->rec_len, blocksize) != blocksize - 12)
+ de = (struct ext4_dir_entry_2 *)(((void *)dirent) + 12);
+ if (ext4_rec_len_from_disk(de->rec_len, blocksize) != blocksize - 12)
return NULL;
- root = (struct dx_root_info *)(((void *)dp + 12));
+ root = (struct dx_root_info *)(((void *)de + 12));
if (root->reserved_zero ||
root->info_length != sizeof(struct dx_root_info))
return NULL;
@@ -438,7 +438,7 @@ static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
return (struct dx_countlimit *)(((void *)dirent) + count_offset);
}
-static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent,
+static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry_2 *dirent,
int count_offset, int count, struct dx_tail *t)
{
struct ext4_inode_info *ei = EXT4_I(inode);
@@ -456,7 +456,7 @@ static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent,
}
static int ext4_dx_csum_verify(struct inode *inode,
- struct ext4_dir_entry *dirent)
+ struct ext4_dir_entry_2 *dirent)
{
struct dx_countlimit *c;
struct dx_tail *t;
@@ -489,7 +489,7 @@ static int ext4_dx_csum_verify(struct inode *inode,
return 1;
}
-static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry *dirent)
+static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry_2 *dirent)
{
struct dx_countlimit *c;
struct dx_tail *t;
@@ -523,7 +523,7 @@ static inline int ext4_handle_dirty_dx_node(handle_t *handle,
struct inode *inode,
struct buffer_head *bh)
{
- ext4_dx_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
+ ext4_dx_csum_set(inode, (struct ext4_dir_entry_2 *)bh->b_data);
return ext4_handle_dirty_metadata(handle, inode, bh);
}
@@ -1496,7 +1496,7 @@ int ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size,
}
static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
- struct ext4_dir_entry *de)
+ struct ext4_dir_entry_2 *de)
{
struct super_block *sb = dir->i_sb;
@@ -1627,7 +1627,7 @@ static struct buffer_head *__ext4_find_entry(struct inode *dir,
}
if (!buffer_verified(bh) &&
!is_dx_internal_node(dir, block,
- (struct ext4_dir_entry *)bh->b_data) &&
+ (struct ext4_dir_entry_2 *)bh->b_data) &&
!ext4_dirblock_csum_verify(dir, bh)) {
EXT4_ERROR_INODE_ERR(dir, EFSBADCRC,
"checksumming directory "
--
2.43.7
^ permalink raw reply related
* [PATCH v4 01/11] ext4: validate count against limit in ext4_dx_csum_verify/_set
From: Artem Blagodarenko @ 2026-06-24 13:36 UTC (permalink / raw)
To: linux-ext4
Cc: adilger.kernel, Artem Blagodarenko, xiaowu.417,
Artem Blagodarenko
In-Reply-To: <20260624133642.18438-1-ablagodarenko@thelustrecollective.com>
dx_countlimit's count field was read from disk and used directly to
compute the checksummed range (count_offset + count * sizeof(dx_entry))
without ever being checked against limit -- only limit itself was
bounds-checked against the block size. A corrupted or maliciously
crafted filesystem image that sets count to a large value (e.g. 65535)
makes ext4_chksum() read far past the end of the directory block
buffer, hitting adjacent slab objects.
Reported-by: xiaowu.417@qq.com
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
---
fs/ext4/namei.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index cc49ae04a6f6..a283e285937a 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -477,6 +477,10 @@ static int ext4_dx_csum_verify(struct inode *inode,
warn_no_space_for_csum(inode);
return 0;
}
+ if (count > limit) {
+ EXT4_ERROR_INODE(inode, "dir seems corrupt? Run e2fsck -D.");
+ return 0;
+ }
t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
if (t->dt_checksum != ext4_dx_csum(inode, dirent, count_offset,
@@ -506,6 +510,10 @@ static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry *dirent)
warn_no_space_for_csum(inode);
return;
}
+ if (count > limit) {
+ EXT4_ERROR_INODE(inode, "dir seems corrupt? Run e2fsck -D.");
+ return;
+ }
t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
t->dt_checksum = ext4_dx_csum(inode, dirent, count_offset, count, t);
--
2.43.7
^ permalink raw reply related
* [PATCH v4 00/11] Data in direntry (dirdata) feature
From: Artem Blagodarenko @ 2026-06-24 13:36 UTC (permalink / raw)
To: linux-ext4; +Cc: adilger.kernel, Artem Blagodarenko
EXT4 currently stores a hash in the directory entry
(dirent) immediately after the file name to support
simultaneous fscrypt and casefold functionality.
It has been discussed within the EXT4 community that
this hash could instead be stored in dirdata. This
would make it the second (or third, in the case of
64-bit inode counts) user of dirdata.
At the same time, the existing format—where the hash
is placed after the file name—must continue to be
supported. With these patches, EXT4 can handle the
hash in both formats.
The first user of this feature is LUFID -
Locally Unique File ID.
Support for fscrypt and case-insensitive directories
with dirdata enabled has been verified using a
dedicated xfstest submitted to the xfstests list as
a separate patch.
e2fsprogs support is provided in a separate patches
series.
Changes in v4:
- syzbot ci actually ran the v3 series and found real,
reproducible KASAN slab-out-of-bounds and use-after-free
reads, all rooted in ext4_dir_entry_len() decoding
de->rec_len with a hardcoded full-block size even when
the entry lives in a smaller buffer (inline directory
data). Gave it an explicit blocksize parameter and fixed
every caller to pass the real containing-buffer size.
- dx_get_dx_info() and get_dx_countlimit() additionally
needed dir=NULL (not just the right blocksize) when
computing past the on-disk '.'/'..' entries, since those
never carry the casefold+fscrypt hash regardless of the
directory's feature flags; passing the real dir made
ext4_dirent_rec_len() add 8 bytes of hash space that was
never written on disk, corrupting dx_root_info's offset
for every casefold+encrypt directory.
- ext4_dirdata_get()/ext4_dirdata_set(): fixed bounds checks
that were off by EXT4_BASE_DIR_LEN (the 8-byte dirent
header), a LUFID memcpy that used the wrong source/length,
an out-of-bounds array write for maximum-length filenames,
and an uninitialized gap byte leaking a stale memory byte
to disk.
- EXT4_IOC_SET_LUFID: fixed ddh_length under-counting the
header byte (silently dropping the last byte of every
LUFID payload), rejected '.'/'..' as targets, added a
missing inode_permission(dir, MAY_WRITE) check, and closed
a data race on the shared i_dirdata field by also locking
the target inode (not just the parent directory) for the
duration it's used.
- Fixed a missing bounds check in ext4_dx_csum_verify()/
ext4_dx_csum_set() that let an unvalidated on-disk `count`
field drive an out-of-bounds checksum read. This bug
predates this series, but is included as patch 1 (ahead
of the patch that touches this function) since it was
found via review of this series.
- Thanks to Sashiko AI review and to Xiao (xiaowu.417@qq.com)
for reproducing several of the above with concrete crash
logs and PoCs.
Artem Blagodarenko (11):
ext4: validate count against limit in ext4_dx_csum_verify/_set
ext4: replace ext4_dir_entry with ext4_dir_entry_2
ext4: add ext4_dir_entry_is_tail()
ext4: refactor dx_root to support variable dirent sizes
ext4: add dirdata format definitions and access helpers
ext4: preserve dirdata bits in get_dtype()
ext4: add ext4_dir_entry_len() and harden dirdata parsing
ext4: rename ext4_dir_rec_len() and clarify dirdata usage
ext4: dirdata feature
ext4: add dirdata set/get helpers
ext4: Add EXT4_IOC_SET_LUFID ioctl for setting LUFID on directory
entries
foofile.txt | 0
fs/ext4/dir.c | 9 +-
fs/ext4/ext4.h | 211 +++++++++++-
fs/ext4/inline.c | 41 ++-
fs/ext4/ioctl.c | 84 +++++
fs/ext4/namei.c | 699 +++++++++++++++++++++++++++++---------
fs/ext4/sysfs.c | 2 +
include/uapi/linux/ext4.h | 13 +
8 files changed, 861 insertions(+), 198 deletions(-)
create mode 100644 foofile.txt
--
2.43.7
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