* [PATCH v12 04/17] xfs: separate out setting buftarg atomic writes limits
From: John Garry @ 2025-05-06 9:04 UTC (permalink / raw)
To: brauner, djwong, hch, viro, jack, cem
Cc: linux-fsdevel, dchinner, linux-xfs, linux-kernel, ojaswin,
ritesh.list, martin.petersen, linux-ext4, linux-block,
catherine.hoang, linux-api, John Garry
In-Reply-To: <20250506090427.2549456-1-john.g.garry@oracle.com>
From: "Darrick J. Wong" <djwong@kernel.org>
Separate out setting buftarg atomic writes limits into a dedicated
function, xfs_configure_buftarg_atomic_writes(), to keep the specific
functionality self-contained.
For naming consistency, rename xfs_setsize_buftarg() ->
xfs_configure_buftarg().
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
[jpg: separate out from patch "xfs: ignore HW which ..."]
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/xfs_buf.c | 32 ++++++++++++++++++++++++--------
fs/xfs/xfs_buf.h | 2 +-
fs/xfs/xfs_super.c | 6 +++---
3 files changed, 28 insertions(+), 12 deletions(-)
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index d8f90bdd2a33..e2374c503e79 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1714,13 +1714,33 @@ xfs_free_buftarg(
kfree(btp);
}
+/*
+ * Configure this buffer target for hardware-assisted atomic writes if the
+ * underlying block device supports is congruent with the filesystem geometry.
+ */
+static inline void
+xfs_configure_buftarg_atomic_writes(
+ struct xfs_buftarg *btp)
+{
+ unsigned int min_bytes, max_bytes;
+
+ min_bytes = bdev_atomic_write_unit_min_bytes(btp->bt_bdev);
+ max_bytes = bdev_atomic_write_unit_max_bytes(btp->bt_bdev);
+
+ btp->bt_bdev_awu_min = min_bytes;
+ btp->bt_bdev_awu_max = max_bytes;
+}
+
+/* Configure a buffer target that abstracts a block device. */
int
-xfs_setsize_buftarg(
+xfs_configure_buftarg(
struct xfs_buftarg *btp,
unsigned int sectorsize)
{
int error;
+ ASSERT(btp->bt_bdev != NULL);
+
/* Set up metadata sector size info */
btp->bt_meta_sectorsize = sectorsize;
btp->bt_meta_sectormask = sectorsize - 1;
@@ -1733,6 +1753,9 @@ xfs_setsize_buftarg(
return -EINVAL;
}
+ if (bdev_can_atomic_write(btp->bt_bdev))
+ xfs_configure_buftarg_atomic_writes(btp);
+
return 0;
}
@@ -1797,13 +1820,6 @@ xfs_alloc_buftarg(
btp->bt_daxdev = fs_dax_get_by_bdev(btp->bt_bdev, &btp->bt_dax_part_off,
mp, ops);
- if (bdev_can_atomic_write(btp->bt_bdev)) {
- btp->bt_bdev_awu_min = bdev_atomic_write_unit_min_bytes(
- btp->bt_bdev);
- btp->bt_bdev_awu_max = bdev_atomic_write_unit_max_bytes(
- btp->bt_bdev);
- }
-
/*
* Flush and invalidate all devices' pagecaches before reading any
* metadata because XFS doesn't use the bdev pagecache.
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index d0b065a9a9f0..a7026fb255c4 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -374,7 +374,7 @@ struct xfs_buftarg *xfs_alloc_buftarg(struct xfs_mount *mp,
extern void xfs_free_buftarg(struct xfs_buftarg *);
extern void xfs_buftarg_wait(struct xfs_buftarg *);
extern void xfs_buftarg_drain(struct xfs_buftarg *);
-extern int xfs_setsize_buftarg(struct xfs_buftarg *, unsigned int);
+int xfs_configure_buftarg(struct xfs_buftarg *btp, unsigned int sectorsize);
#define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
#define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 6eba90eb7297..77a3c003fc4f 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -537,7 +537,7 @@ xfs_setup_devices(
{
int error;
- error = xfs_setsize_buftarg(mp->m_ddev_targp, mp->m_sb.sb_sectsize);
+ error = xfs_configure_buftarg(mp->m_ddev_targp, mp->m_sb.sb_sectsize);
if (error)
return error;
@@ -546,7 +546,7 @@ xfs_setup_devices(
if (xfs_has_sector(mp))
log_sector_size = mp->m_sb.sb_logsectsize;
- error = xfs_setsize_buftarg(mp->m_logdev_targp,
+ error = xfs_configure_buftarg(mp->m_logdev_targp,
log_sector_size);
if (error)
return error;
@@ -560,7 +560,7 @@ xfs_setup_devices(
}
mp->m_rtdev_targp = mp->m_ddev_targp;
} else if (mp->m_rtname) {
- error = xfs_setsize_buftarg(mp->m_rtdev_targp,
+ error = xfs_configure_buftarg(mp->m_rtdev_targp,
mp->m_sb.sb_sectsize);
if (error)
return error;
--
2.31.1
^ permalink raw reply related
* [PATCH v12 02/17] xfs: only call xfs_setsize_buftarg once per buffer target
From: John Garry @ 2025-05-06 9:04 UTC (permalink / raw)
To: brauner, djwong, hch, viro, jack, cem
Cc: linux-fsdevel, dchinner, linux-xfs, linux-kernel, ojaswin,
ritesh.list, martin.petersen, linux-ext4, linux-block,
catherine.hoang, linux-api, John Garry
In-Reply-To: <20250506090427.2549456-1-john.g.garry@oracle.com>
From: "Darrick J. Wong" <djwong@kernel.org>
It's silly to call xfs_setsize_buftarg from xfs_alloc_buftarg with the
block device LBA size because we don't need to ask the block layer to
validate a geometry number that it provided us. Instead, set the
preliminary bt_meta_sector* fields to the LBA size in preparation for
reading the primary super.
However, we still want to flush and invalidate the pagecache for all
three block devices before we start reading metadata from those devices,
so call sync_blockdev() per bdev in xfs_alloc_buftarg().
This will enable a subsequent patch to validate hw atomic write geometry
against the filesystem geometry.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: John Garry <john.g.garry@oracle.com>
[jpg: call sync_blockdev() from xfs_alloc_buftarg()]
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
fs/xfs/xfs_buf.c | 28 ++++++++++++++++++----------
fs/xfs/xfs_super.c | 16 ++++++++++++----
2 files changed, 30 insertions(+), 14 deletions(-)
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 5ae77ffdc947..d8f90bdd2a33 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1733,11 +1733,7 @@ xfs_setsize_buftarg(
return -EINVAL;
}
- /*
- * Flush the block device pagecache so our bios see anything dirtied
- * before mount.
- */
- return sync_blockdev(btp->bt_bdev);
+ return 0;
}
int
@@ -1786,6 +1782,8 @@ xfs_alloc_buftarg(
{
struct xfs_buftarg *btp;
const struct dax_holder_operations *ops = NULL;
+ int error;
+
#if defined(CONFIG_FS_DAX) && defined(CONFIG_MEMORY_FAILURE)
ops = &xfs_dax_holder_operations;
@@ -1806,21 +1804,31 @@ xfs_alloc_buftarg(
btp->bt_bdev);
}
+ /*
+ * Flush and invalidate all devices' pagecaches before reading any
+ * metadata because XFS doesn't use the bdev pagecache.
+ */
+ error = sync_blockdev(btp->bt_bdev);
+ if (error)
+ goto error_free;
+
/*
* When allocating the buftargs we have not yet read the super block and
* thus don't know the file system sector size yet.
*/
- if (xfs_setsize_buftarg(btp, bdev_logical_block_size(btp->bt_bdev)))
- goto error_free;
- if (xfs_init_buftarg(btp, bdev_logical_block_size(btp->bt_bdev),
- mp->m_super->s_id))
+ btp->bt_meta_sectorsize = bdev_logical_block_size(btp->bt_bdev);
+ btp->bt_meta_sectormask = btp->bt_meta_sectorsize - 1;
+
+ error = xfs_init_buftarg(btp, btp->bt_meta_sectorsize,
+ mp->m_super->s_id);
+ if (error)
goto error_free;
return btp;
error_free:
kfree(btp);
- return NULL;
+ return ERR_PTR(error);
}
static inline void
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 5e456a6073ca..6eba90eb7297 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -482,21 +482,29 @@ xfs_open_devices(
/*
* Setup xfs_mount buffer target pointers
*/
- error = -ENOMEM;
mp->m_ddev_targp = xfs_alloc_buftarg(mp, sb->s_bdev_file);
- if (!mp->m_ddev_targp)
+ if (IS_ERR(mp->m_ddev_targp)) {
+ error = PTR_ERR(mp->m_ddev_targp);
+ mp->m_ddev_targp = NULL;
goto out_close_rtdev;
+ }
if (rtdev_file) {
mp->m_rtdev_targp = xfs_alloc_buftarg(mp, rtdev_file);
- if (!mp->m_rtdev_targp)
+ if (IS_ERR(mp->m_rtdev_targp)) {
+ error = PTR_ERR(mp->m_rtdev_targp);
+ mp->m_rtdev_targp = NULL;
goto out_free_ddev_targ;
+ }
}
if (logdev_file && file_bdev(logdev_file) != ddev) {
mp->m_logdev_targp = xfs_alloc_buftarg(mp, logdev_file);
- if (!mp->m_logdev_targp)
+ if (IS_ERR(mp->m_logdev_targp)) {
+ error = PTR_ERR(mp->m_logdev_targp);
+ mp->m_logdev_targp = NULL;
goto out_free_rtdev_targ;
+ }
} else {
mp->m_logdev_targp = mp->m_ddev_targp;
/* Handle won't be used, drop it */
--
2.31.1
^ permalink raw reply related
* [PATCH v12 06/17] xfs: add helpers to compute transaction reservation for finishing intent items
From: John Garry @ 2025-05-06 9:04 UTC (permalink / raw)
To: brauner, djwong, hch, viro, jack, cem
Cc: linux-fsdevel, dchinner, linux-xfs, linux-kernel, ojaswin,
ritesh.list, martin.petersen, linux-ext4, linux-block,
catherine.hoang, linux-api, John Garry
In-Reply-To: <20250506090427.2549456-1-john.g.garry@oracle.com>
From: "Darrick J. Wong" <djwong@kernel.org>
In the transaction reservation code, hoist the logic that computes the
reservation needed to finish one log intent item into separate helper
functions. These will be used in subsequent patches to estimate the
number of blocks that an online repair can commit to reaping in the same
transaction as the change committing the new data structure.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
fs/xfs/libxfs/xfs_trans_resv.c | 165 ++++++++++++++++++++++++++-------
fs/xfs/libxfs/xfs_trans_resv.h | 18 ++++
2 files changed, 152 insertions(+), 31 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c
index 13d00c7166e1..580d00ae2857 100644
--- a/fs/xfs/libxfs/xfs_trans_resv.c
+++ b/fs/xfs/libxfs/xfs_trans_resv.c
@@ -263,6 +263,42 @@ xfs_rtalloc_block_count(
* register overflow from temporaries in the calculations.
*/
+/*
+ * Finishing a data device refcount updates (t1):
+ * the agfs of the ags containing the blocks: nr_ops * sector size
+ * the refcount btrees: nr_ops * 1 trees * (2 * max depth - 1) * block size
+ */
+inline unsigned int
+xfs_calc_finish_cui_reservation(
+ struct xfs_mount *mp,
+ unsigned int nr_ops)
+{
+ if (!xfs_has_reflink(mp))
+ return 0;
+
+ return xfs_calc_buf_res(nr_ops, mp->m_sb.sb_sectsize) +
+ xfs_calc_buf_res(xfs_refcountbt_block_count(mp, nr_ops),
+ mp->m_sb.sb_blocksize);
+}
+
+/*
+ * Realtime refcount updates (t2);
+ * the rt refcount inode
+ * the rtrefcount btrees: nr_ops * 1 trees * (2 * max depth - 1) * block size
+ */
+inline unsigned int
+xfs_calc_finish_rt_cui_reservation(
+ struct xfs_mount *mp,
+ unsigned int nr_ops)
+{
+ if (!xfs_has_rtreflink(mp))
+ return 0;
+
+ return xfs_calc_inode_res(mp, 1) +
+ xfs_calc_buf_res(xfs_rtrefcountbt_block_count(mp, nr_ops),
+ mp->m_sb.sb_blocksize);
+}
+
/*
* Compute the log reservation required to handle the refcount update
* transaction. Refcount updates are always done via deferred log items.
@@ -280,19 +316,10 @@ xfs_calc_refcountbt_reservation(
struct xfs_mount *mp,
unsigned int nr_ops)
{
- unsigned int blksz = XFS_FSB_TO_B(mp, 1);
- unsigned int t1, t2 = 0;
+ unsigned int t1, t2;
- if (!xfs_has_reflink(mp))
- return 0;
-
- t1 = xfs_calc_buf_res(nr_ops, mp->m_sb.sb_sectsize) +
- xfs_calc_buf_res(xfs_refcountbt_block_count(mp, nr_ops), blksz);
-
- if (xfs_has_realtime(mp))
- t2 = xfs_calc_inode_res(mp, 1) +
- xfs_calc_buf_res(xfs_rtrefcountbt_block_count(mp, nr_ops),
- blksz);
+ t1 = xfs_calc_finish_cui_reservation(mp, nr_ops);
+ t2 = xfs_calc_finish_rt_cui_reservation(mp, nr_ops);
return max(t1, t2);
}
@@ -379,6 +406,96 @@ xfs_calc_write_reservation_minlogsize(
return xfs_calc_write_reservation(mp, true);
}
+/*
+ * Finishing an EFI can free the blocks and bmap blocks (t2):
+ * the agf for each of the ags: nr * sector size
+ * the agfl for each of the ags: nr * sector size
+ * the super block to reflect the freed blocks: sector size
+ * worst case split in allocation btrees per extent assuming nr extents:
+ * nr exts * 2 trees * (2 * max depth - 1) * block size
+ */
+inline unsigned int
+xfs_calc_finish_efi_reservation(
+ struct xfs_mount *mp,
+ unsigned int nr)
+{
+ return xfs_calc_buf_res((2 * nr) + 1, mp->m_sb.sb_sectsize) +
+ xfs_calc_buf_res(xfs_allocfree_block_count(mp, nr),
+ mp->m_sb.sb_blocksize);
+}
+
+/*
+ * Or, if it's a realtime file (t3):
+ * the agf for each of the ags: 2 * sector size
+ * the agfl for each of the ags: 2 * sector size
+ * the super block to reflect the freed blocks: sector size
+ * the realtime bitmap:
+ * 2 exts * ((XFS_BMBT_MAX_EXTLEN / rtextsize) / NBBY) bytes
+ * the realtime summary: 2 exts * 1 block
+ * worst case split in allocation btrees per extent assuming 2 extents:
+ * 2 exts * 2 trees * (2 * max depth - 1) * block size
+ */
+inline unsigned int
+xfs_calc_finish_rt_efi_reservation(
+ struct xfs_mount *mp,
+ unsigned int nr)
+{
+ if (!xfs_has_realtime(mp))
+ return 0;
+
+ return xfs_calc_buf_res((2 * nr) + 1, mp->m_sb.sb_sectsize) +
+ xfs_calc_buf_res(xfs_rtalloc_block_count(mp, nr),
+ mp->m_sb.sb_blocksize) +
+ xfs_calc_buf_res(xfs_allocfree_block_count(mp, nr),
+ mp->m_sb.sb_blocksize);
+}
+
+/*
+ * Finishing an RUI is the same as an EFI. We can split the rmap btree twice
+ * on each end of the record, and that can cause the AGFL to be refilled or
+ * emptied out.
+ */
+inline unsigned int
+xfs_calc_finish_rui_reservation(
+ struct xfs_mount *mp,
+ unsigned int nr)
+{
+ if (!xfs_has_rmapbt(mp))
+ return 0;
+ return xfs_calc_finish_efi_reservation(mp, nr);
+}
+
+/*
+ * Finishing an RUI is the same as an EFI. We can split the rmap btree twice
+ * on each end of the record, and that can cause the AGFL to be refilled or
+ * emptied out.
+ */
+inline unsigned int
+xfs_calc_finish_rt_rui_reservation(
+ struct xfs_mount *mp,
+ unsigned int nr)
+{
+ if (!xfs_has_rtrmapbt(mp))
+ return 0;
+ return xfs_calc_finish_rt_efi_reservation(mp, nr);
+}
+
+/*
+ * In finishing a BUI, we can modify:
+ * the inode being truncated: inode size
+ * dquots
+ * the inode's bmap btree: (max depth + 1) * block size
+ */
+inline unsigned int
+xfs_calc_finish_bui_reservation(
+ struct xfs_mount *mp,
+ unsigned int nr)
+{
+ return xfs_calc_inode_res(mp, 1) + XFS_DQUOT_LOGRES +
+ xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1,
+ mp->m_sb.sb_blocksize);
+}
+
/*
* In truncating a file we free up to two extents at once. We can modify (t1):
* the inode being truncated: inode size
@@ -411,16 +528,8 @@ xfs_calc_itruncate_reservation(
t1 = xfs_calc_inode_res(mp, 1) +
xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, blksz);
- t2 = xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) +
- xfs_calc_buf_res(xfs_allocfree_block_count(mp, 4), blksz);
-
- if (xfs_has_realtime(mp)) {
- t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) +
- xfs_calc_buf_res(xfs_rtalloc_block_count(mp, 2), blksz) +
- xfs_calc_buf_res(xfs_allocfree_block_count(mp, 2), blksz);
- } else {
- t3 = 0;
- }
+ t2 = xfs_calc_finish_efi_reservation(mp, 4);
+ t3 = xfs_calc_finish_rt_efi_reservation(mp, 2);
/*
* In the early days of reflink, we included enough reservation to log
@@ -501,9 +610,7 @@ xfs_calc_rename_reservation(
xfs_calc_buf_res(2 * XFS_DIROP_LOG_COUNT(mp),
XFS_FSB_TO_B(mp, 1));
- t2 = xfs_calc_buf_res(7, mp->m_sb.sb_sectsize) +
- xfs_calc_buf_res(xfs_allocfree_block_count(mp, 3),
- XFS_FSB_TO_B(mp, 1));
+ t2 = xfs_calc_finish_efi_reservation(mp, 3);
if (xfs_has_parent(mp)) {
unsigned int rename_overhead, exchange_overhead;
@@ -611,9 +718,7 @@ xfs_calc_link_reservation(
overhead += xfs_calc_iunlink_remove_reservation(mp);
t1 = xfs_calc_inode_res(mp, 2) +
xfs_calc_buf_res(XFS_DIROP_LOG_COUNT(mp), XFS_FSB_TO_B(mp, 1));
- t2 = xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) +
- xfs_calc_buf_res(xfs_allocfree_block_count(mp, 1),
- XFS_FSB_TO_B(mp, 1));
+ t2 = xfs_calc_finish_efi_reservation(mp, 1);
if (xfs_has_parent(mp)) {
t3 = resp->tr_attrsetm.tr_logres;
@@ -676,9 +781,7 @@ xfs_calc_remove_reservation(
t1 = xfs_calc_inode_res(mp, 2) +
xfs_calc_buf_res(XFS_DIROP_LOG_COUNT(mp), XFS_FSB_TO_B(mp, 1));
- t2 = xfs_calc_buf_res(4, mp->m_sb.sb_sectsize) +
- xfs_calc_buf_res(xfs_allocfree_block_count(mp, 2),
- XFS_FSB_TO_B(mp, 1));
+ t2 = xfs_calc_finish_efi_reservation(mp, 2);
if (xfs_has_parent(mp)) {
t3 = resp->tr_attrrm.tr_logres;
diff --git a/fs/xfs/libxfs/xfs_trans_resv.h b/fs/xfs/libxfs/xfs_trans_resv.h
index 0554b9d775d2..d9d0032cbbc5 100644
--- a/fs/xfs/libxfs/xfs_trans_resv.h
+++ b/fs/xfs/libxfs/xfs_trans_resv.h
@@ -98,6 +98,24 @@ struct xfs_trans_resv {
void xfs_trans_resv_calc(struct xfs_mount *mp, struct xfs_trans_resv *resp);
uint xfs_allocfree_block_count(struct xfs_mount *mp, uint num_ops);
+unsigned int xfs_calc_finish_bui_reservation(struct xfs_mount *mp,
+ unsigned int nr_ops);
+
+unsigned int xfs_calc_finish_efi_reservation(struct xfs_mount *mp,
+ unsigned int nr_ops);
+unsigned int xfs_calc_finish_rt_efi_reservation(struct xfs_mount *mp,
+ unsigned int nr_ops);
+
+unsigned int xfs_calc_finish_rui_reservation(struct xfs_mount *mp,
+ unsigned int nr_ops);
+unsigned int xfs_calc_finish_rt_rui_reservation(struct xfs_mount *mp,
+ unsigned int nr_ops);
+
+unsigned int xfs_calc_finish_cui_reservation(struct xfs_mount *mp,
+ unsigned int nr_ops);
+unsigned int xfs_calc_finish_rt_cui_reservation(struct xfs_mount *mp,
+ unsigned int nr_ops);
+
unsigned int xfs_calc_itruncate_reservation_minlogsize(struct xfs_mount *mp);
unsigned int xfs_calc_write_reservation_minlogsize(struct xfs_mount *mp);
unsigned int xfs_calc_qm_dqalloc_reservation_minlogsize(struct xfs_mount *mp);
--
2.31.1
^ permalink raw reply related
* [PATCH v12 05/17] xfs: add helpers to compute log item overhead
From: John Garry @ 2025-05-06 9:04 UTC (permalink / raw)
To: brauner, djwong, hch, viro, jack, cem
Cc: linux-fsdevel, dchinner, linux-xfs, linux-kernel, ojaswin,
ritesh.list, martin.petersen, linux-ext4, linux-block,
catherine.hoang, linux-api, John Garry
In-Reply-To: <20250506090427.2549456-1-john.g.garry@oracle.com>
From: "Darrick J. Wong" <djwong@kernel.org>
Add selected helpers to estimate the transaction reservation required to
write various log intent and buffer items to the log. These helpers
will be used by the online repair code for more precise estimations of
how much work can be done in a single transaction.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
fs/xfs/xfs_bmap_item.c | 10 ++++++++++
fs/xfs/xfs_bmap_item.h | 3 +++
fs/xfs/xfs_buf_item.c | 19 +++++++++++++++++++
fs/xfs/xfs_buf_item.h | 3 +++
fs/xfs/xfs_extfree_item.c | 10 ++++++++++
fs/xfs/xfs_extfree_item.h | 3 +++
fs/xfs/xfs_log_cil.c | 4 +---
fs/xfs/xfs_log_priv.h | 13 +++++++++++++
fs/xfs/xfs_refcount_item.c | 10 ++++++++++
fs/xfs/xfs_refcount_item.h | 3 +++
fs/xfs/xfs_rmap_item.c | 10 ++++++++++
fs/xfs/xfs_rmap_item.h | 3 +++
12 files changed, 88 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c
index 3d52e9d7ad57..646c515ee355 100644
--- a/fs/xfs/xfs_bmap_item.c
+++ b/fs/xfs/xfs_bmap_item.c
@@ -77,6 +77,11 @@ xfs_bui_item_size(
*nbytes += xfs_bui_log_format_sizeof(buip->bui_format.bui_nextents);
}
+unsigned int xfs_bui_log_space(unsigned int nr)
+{
+ return xlog_item_space(1, xfs_bui_log_format_sizeof(nr));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given bui log item. We use only 1 iovec, and we point that
@@ -168,6 +173,11 @@ xfs_bud_item_size(
*nbytes += sizeof(struct xfs_bud_log_format);
}
+unsigned int xfs_bud_log_space(void)
+{
+ return xlog_item_space(1, sizeof(struct xfs_bud_log_format));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given bud log item. We use only 1 iovec, and we point that
diff --git a/fs/xfs/xfs_bmap_item.h b/fs/xfs/xfs_bmap_item.h
index 6fee6a508343..b42fee06899d 100644
--- a/fs/xfs/xfs_bmap_item.h
+++ b/fs/xfs/xfs_bmap_item.h
@@ -72,4 +72,7 @@ struct xfs_bmap_intent;
void xfs_bmap_defer_add(struct xfs_trans *tp, struct xfs_bmap_intent *bi);
+unsigned int xfs_bui_log_space(unsigned int nr);
+unsigned int xfs_bud_log_space(void);
+
#endif /* __XFS_BMAP_ITEM_H__ */
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 19eb0b7a3e58..90139e0f3271 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -103,6 +103,25 @@ xfs_buf_item_size_segment(
return;
}
+/*
+ * Compute the worst case log item overhead for an invalidated buffer with the
+ * given map count and block size.
+ */
+unsigned int
+xfs_buf_inval_log_space(
+ unsigned int map_count,
+ unsigned int blocksize)
+{
+ unsigned int chunks = DIV_ROUND_UP(blocksize, XFS_BLF_CHUNK);
+ unsigned int bitmap_size = DIV_ROUND_UP(chunks, NBWORD);
+ unsigned int ret =
+ offsetof(struct xfs_buf_log_format, blf_data_map) +
+ (bitmap_size * sizeof_field(struct xfs_buf_log_format,
+ blf_data_map[0]));
+
+ return ret * map_count;
+}
+
/*
* Return the number of log iovecs and space needed to log the given buf log
* item.
diff --git a/fs/xfs/xfs_buf_item.h b/fs/xfs/xfs_buf_item.h
index 8cde85259a58..e10e324cd245 100644
--- a/fs/xfs/xfs_buf_item.h
+++ b/fs/xfs/xfs_buf_item.h
@@ -64,6 +64,9 @@ static inline void xfs_buf_dquot_iodone(struct xfs_buf *bp)
void xfs_buf_iodone(struct xfs_buf *);
bool xfs_buf_log_check_iovec(struct xfs_log_iovec *iovec);
+unsigned int xfs_buf_inval_log_space(unsigned int map_count,
+ unsigned int blocksize);
+
extern struct kmem_cache *xfs_buf_item_cache;
#endif /* __XFS_BUF_ITEM_H__ */
diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c
index 777438b853da..d574f5f639fa 100644
--- a/fs/xfs/xfs_extfree_item.c
+++ b/fs/xfs/xfs_extfree_item.c
@@ -83,6 +83,11 @@ xfs_efi_item_size(
*nbytes += xfs_efi_log_format_sizeof(efip->efi_format.efi_nextents);
}
+unsigned int xfs_efi_log_space(unsigned int nr)
+{
+ return xlog_item_space(1, xfs_efi_log_format_sizeof(nr));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given efi log item. We use only 1 iovec, and we point that
@@ -254,6 +259,11 @@ xfs_efd_item_size(
*nbytes += xfs_efd_log_format_sizeof(efdp->efd_format.efd_nextents);
}
+unsigned int xfs_efd_log_space(unsigned int nr)
+{
+ return xlog_item_space(1, xfs_efd_log_format_sizeof(nr));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given efd log item. We use only 1 iovec, and we point that
diff --git a/fs/xfs/xfs_extfree_item.h b/fs/xfs/xfs_extfree_item.h
index 41b7c4306079..c8402040410b 100644
--- a/fs/xfs/xfs_extfree_item.h
+++ b/fs/xfs/xfs_extfree_item.h
@@ -94,4 +94,7 @@ void xfs_extent_free_defer_add(struct xfs_trans *tp,
struct xfs_extent_free_item *xefi,
struct xfs_defer_pending **dfpp);
+unsigned int xfs_efi_log_space(unsigned int nr);
+unsigned int xfs_efd_log_space(unsigned int nr);
+
#endif /* __XFS_EXTFREE_ITEM_H__ */
diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c
index 1ca406ec1b40..f66d2d430e4f 100644
--- a/fs/xfs/xfs_log_cil.c
+++ b/fs/xfs/xfs_log_cil.c
@@ -309,9 +309,7 @@ xlog_cil_alloc_shadow_bufs(
* Then round nbytes up to 64-bit alignment so that the initial
* buffer alignment is easy to calculate and verify.
*/
- nbytes += niovecs *
- (sizeof(uint64_t) + sizeof(struct xlog_op_header));
- nbytes = round_up(nbytes, sizeof(uint64_t));
+ nbytes = xlog_item_space(niovecs, nbytes);
/*
* The data buffer needs to start 64-bit aligned, so round up
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index f3d78869e5e5..39a102cc1b43 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -698,4 +698,17 @@ xlog_kvmalloc(
return p;
}
+/*
+ * Given a count of iovecs and space for a log item, compute the space we need
+ * in the log to store that data plus the log headers.
+ */
+static inline unsigned int
+xlog_item_space(
+ unsigned int niovecs,
+ unsigned int nbytes)
+{
+ nbytes += niovecs * (sizeof(uint64_t) + sizeof(struct xlog_op_header));
+ return round_up(nbytes, sizeof(uint64_t));
+}
+
#endif /* __XFS_LOG_PRIV_H__ */
diff --git a/fs/xfs/xfs_refcount_item.c b/fs/xfs/xfs_refcount_item.c
index fe2d7aab8554..076501123d89 100644
--- a/fs/xfs/xfs_refcount_item.c
+++ b/fs/xfs/xfs_refcount_item.c
@@ -78,6 +78,11 @@ xfs_cui_item_size(
*nbytes += xfs_cui_log_format_sizeof(cuip->cui_format.cui_nextents);
}
+unsigned int xfs_cui_log_space(unsigned int nr)
+{
+ return xlog_item_space(1, xfs_cui_log_format_sizeof(nr));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given cui log item. We use only 1 iovec, and we point that
@@ -179,6 +184,11 @@ xfs_cud_item_size(
*nbytes += sizeof(struct xfs_cud_log_format);
}
+unsigned int xfs_cud_log_space(void)
+{
+ return xlog_item_space(1, sizeof(struct xfs_cud_log_format));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given cud log item. We use only 1 iovec, and we point that
diff --git a/fs/xfs/xfs_refcount_item.h b/fs/xfs/xfs_refcount_item.h
index bfee8f30c63c..0fc3f493342b 100644
--- a/fs/xfs/xfs_refcount_item.h
+++ b/fs/xfs/xfs_refcount_item.h
@@ -76,4 +76,7 @@ struct xfs_refcount_intent;
void xfs_refcount_defer_add(struct xfs_trans *tp,
struct xfs_refcount_intent *ri);
+unsigned int xfs_cui_log_space(unsigned int nr);
+unsigned int xfs_cud_log_space(void);
+
#endif /* __XFS_REFCOUNT_ITEM_H__ */
diff --git a/fs/xfs/xfs_rmap_item.c b/fs/xfs/xfs_rmap_item.c
index 89decffe76c8..c99700318ec2 100644
--- a/fs/xfs/xfs_rmap_item.c
+++ b/fs/xfs/xfs_rmap_item.c
@@ -77,6 +77,11 @@ xfs_rui_item_size(
*nbytes += xfs_rui_log_format_sizeof(ruip->rui_format.rui_nextents);
}
+unsigned int xfs_rui_log_space(unsigned int nr)
+{
+ return xlog_item_space(1, xfs_rui_log_format_sizeof(nr));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given rui log item. We use only 1 iovec, and we point that
@@ -180,6 +185,11 @@ xfs_rud_item_size(
*nbytes += sizeof(struct xfs_rud_log_format);
}
+unsigned int xfs_rud_log_space(void)
+{
+ return xlog_item_space(1, sizeof(struct xfs_rud_log_format));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given rud log item. We use only 1 iovec, and we point that
diff --git a/fs/xfs/xfs_rmap_item.h b/fs/xfs/xfs_rmap_item.h
index 40d331555675..3a99f0117f2d 100644
--- a/fs/xfs/xfs_rmap_item.h
+++ b/fs/xfs/xfs_rmap_item.h
@@ -75,4 +75,7 @@ struct xfs_rmap_intent;
void xfs_rmap_defer_add(struct xfs_trans *tp, struct xfs_rmap_intent *ri);
+unsigned int xfs_rui_log_space(unsigned int nr);
+unsigned int xfs_rud_log_space(void);
+
#endif /* __XFS_RMAP_ITEM_H__ */
--
2.31.1
^ permalink raw reply related
* [PATCH v12 07/17] xfs: ignore HW which cannot atomic write a single block
From: John Garry @ 2025-05-06 9:04 UTC (permalink / raw)
To: brauner, djwong, hch, viro, jack, cem
Cc: linux-fsdevel, dchinner, linux-xfs, linux-kernel, ojaswin,
ritesh.list, martin.petersen, linux-ext4, linux-block,
catherine.hoang, linux-api, John Garry
In-Reply-To: <20250506090427.2549456-1-john.g.garry@oracle.com>
From: "Darrick J. Wong" <djwong@kernel.org>
Currently only HW which can write at least 1x block is supported.
For supporting atomic writes > 1x block, a CoW-based method will also be
used and this will not be resticted to using HW which can write >= 1x
block.
However for deciding if HW-based atomic writes can be used, we need to
start adding checks for write length < HW min, which complicates the
code. Indeed, a statx field similar to unit_max_opt should also be
added for this minimum, which is undesirable.
HW which can only write > 1x blocks would be uncommon and quite weird,
so let's just not support it.
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/xfs_buf.c | 12 ++++++++++++
fs/xfs/xfs_buf.h | 2 +-
fs/xfs/xfs_inode.h | 10 +---------
3 files changed, 14 insertions(+), 10 deletions(-)
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index e2374c503e79..d52d9587b42c 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1722,11 +1722,23 @@ static inline void
xfs_configure_buftarg_atomic_writes(
struct xfs_buftarg *btp)
{
+ struct xfs_mount *mp = btp->bt_mount;
unsigned int min_bytes, max_bytes;
min_bytes = bdev_atomic_write_unit_min_bytes(btp->bt_bdev);
max_bytes = bdev_atomic_write_unit_max_bytes(btp->bt_bdev);
+ /*
+ * Ignore atomic write geometry that is nonsense or doesn't even cover
+ * a single fsblock.
+ */
+ if (min_bytes > max_bytes ||
+ min_bytes > mp->m_sb.sb_blocksize ||
+ max_bytes < mp->m_sb.sb_blocksize) {
+ min_bytes = 0;
+ max_bytes = 0;
+ }
+
btp->bt_bdev_awu_min = min_bytes;
btp->bt_bdev_awu_max = max_bytes;
}
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index a7026fb255c4..9d2ab567cf81 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -112,7 +112,7 @@ struct xfs_buftarg {
struct percpu_counter bt_readahead_count;
struct ratelimit_state bt_ioerror_rl;
- /* Atomic write unit values */
+ /* Atomic write unit values, bytes */
unsigned int bt_bdev_awu_min;
unsigned int bt_bdev_awu_max;
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index d3471a7418b9..d7e2b902ef5c 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -358,15 +358,7 @@ static inline bool xfs_inode_has_bigrtalloc(const struct xfs_inode *ip)
static inline bool xfs_inode_can_hw_atomic_write(const struct xfs_inode *ip)
{
- struct xfs_mount *mp = ip->i_mount;
- struct xfs_buftarg *target = xfs_inode_buftarg(ip);
-
- if (mp->m_sb.sb_blocksize < target->bt_bdev_awu_min)
- return false;
- if (mp->m_sb.sb_blocksize > target->bt_bdev_awu_max)
- return false;
-
- return true;
+ return xfs_inode_buftarg(ip)->bt_bdev_awu_max > 0;
}
/*
--
2.31.1
^ permalink raw reply related
* [PATCH v12 08/17] xfs: allow block allocator to take an alignment hint
From: John Garry @ 2025-05-06 9:04 UTC (permalink / raw)
To: brauner, djwong, hch, viro, jack, cem
Cc: linux-fsdevel, dchinner, linux-xfs, linux-kernel, ojaswin,
ritesh.list, martin.petersen, linux-ext4, linux-block,
catherine.hoang, linux-api, John Garry
In-Reply-To: <20250506090427.2549456-1-john.g.garry@oracle.com>
Add a BMAPI flag to provide a hint to the block allocator to align extents
according to the extszhint.
This will be useful for atomic writes to ensure that we are not being
allocated extents which are not suitable (for atomic writes).
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
fs/xfs/libxfs/xfs_bmap.c | 5 +++++
fs/xfs/libxfs/xfs_bmap.h | 6 +++++-
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 63255820b58a..d954f9b8071f 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -3312,6 +3312,11 @@ xfs_bmap_compute_alignments(
align = xfs_get_cowextsz_hint(ap->ip);
else if (ap->datatype & XFS_ALLOC_USERDATA)
align = xfs_get_extsz_hint(ap->ip);
+
+ /* Try to align start block to any minimum allocation alignment */
+ if (align > 1 && (ap->flags & XFS_BMAPI_EXTSZALIGN))
+ args->alignment = align;
+
if (align) {
if (xfs_bmap_extsize_align(mp, &ap->got, &ap->prev, align, 0,
ap->eof, 0, ap->conv, &ap->offset,
diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h
index b4d9c6e0f3f9..d5f2729305fa 100644
--- a/fs/xfs/libxfs/xfs_bmap.h
+++ b/fs/xfs/libxfs/xfs_bmap.h
@@ -87,6 +87,9 @@ struct xfs_bmalloca {
/* Do not update the rmap btree. Used for reconstructing bmbt from rmapbt. */
#define XFS_BMAPI_NORMAP (1u << 10)
+/* Try to align allocations to the extent size hint */
+#define XFS_BMAPI_EXTSZALIGN (1u << 11)
+
#define XFS_BMAPI_FLAGS \
{ XFS_BMAPI_ENTIRE, "ENTIRE" }, \
{ XFS_BMAPI_METADATA, "METADATA" }, \
@@ -98,7 +101,8 @@ struct xfs_bmalloca {
{ XFS_BMAPI_REMAP, "REMAP" }, \
{ XFS_BMAPI_COWFORK, "COWFORK" }, \
{ XFS_BMAPI_NODISCARD, "NODISCARD" }, \
- { XFS_BMAPI_NORMAP, "NORMAP" }
+ { XFS_BMAPI_NORMAP, "NORMAP" },\
+ { XFS_BMAPI_EXTSZALIGN, "EXTSZALIGN" }
static inline int xfs_bmapi_aflag(int w)
--
2.31.1
^ permalink raw reply related
* [PATCH v12 10/17] xfs: refine atomic write size check in xfs_file_write_iter()
From: John Garry @ 2025-05-06 9:04 UTC (permalink / raw)
To: brauner, djwong, hch, viro, jack, cem
Cc: linux-fsdevel, dchinner, linux-xfs, linux-kernel, ojaswin,
ritesh.list, martin.petersen, linux-ext4, linux-block,
catherine.hoang, linux-api, John Garry
In-Reply-To: <20250506090427.2549456-1-john.g.garry@oracle.com>
Currently the size of atomic write allowed is fixed at the blocksize.
To start to lift this restriction, partly refactor
xfs_report_atomic_write() to into helpers -
xfs_get_atomic_write_{min, max}() - and use those helpers to find the
per-inode atomic write limits and check according to that.
Also add xfs_get_atomic_write_max_opt() to return the optimal limit, and
just return 0 since large atomics aren't supported yet.
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
fs/xfs/xfs_file.c | 12 +++++-------
fs/xfs/xfs_iops.c | 36 +++++++++++++++++++++++++++++++-----
fs/xfs/xfs_iops.h | 3 +++
3 files changed, 39 insertions(+), 12 deletions(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 55bdae44e42a..e8acd6ca8f27 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1032,14 +1032,12 @@ xfs_file_write_iter(
return xfs_file_dax_write(iocb, from);
if (iocb->ki_flags & IOCB_ATOMIC) {
- /*
- * Currently only atomic writing of a single FS block is
- * supported. It would be possible to atomic write smaller than
- * a FS block, but there is no requirement to support this.
- * Note that iomap also does not support this yet.
- */
- if (ocount != ip->i_mount->m_sb.sb_blocksize)
+ if (ocount < xfs_get_atomic_write_min(ip))
return -EINVAL;
+
+ if (ocount > xfs_get_atomic_write_max(ip))
+ return -EINVAL;
+
ret = generic_atomic_write_valid(iocb, from);
if (ret)
return ret;
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 22432c300fd7..77a0606e9dc9 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -601,16 +601,42 @@ xfs_report_dioalign(
stat->dio_offset_align = stat->dio_read_offset_align;
}
+unsigned int
+xfs_get_atomic_write_min(
+ struct xfs_inode *ip)
+{
+ if (!xfs_inode_can_hw_atomic_write(ip))
+ return 0;
+
+ return ip->i_mount->m_sb.sb_blocksize;
+}
+
+unsigned int
+xfs_get_atomic_write_max(
+ struct xfs_inode *ip)
+{
+ if (!xfs_inode_can_hw_atomic_write(ip))
+ return 0;
+
+ return ip->i_mount->m_sb.sb_blocksize;
+}
+
+unsigned int
+xfs_get_atomic_write_max_opt(
+ struct xfs_inode *ip)
+{
+ return 0;
+}
+
static void
xfs_report_atomic_write(
struct xfs_inode *ip,
struct kstat *stat)
{
- unsigned int unit_min = 0, unit_max = 0;
-
- if (xfs_inode_can_hw_atomic_write(ip))
- unit_min = unit_max = ip->i_mount->m_sb.sb_blocksize;
- generic_fill_statx_atomic_writes(stat, unit_min, unit_max, 0);
+ generic_fill_statx_atomic_writes(stat,
+ xfs_get_atomic_write_min(ip),
+ xfs_get_atomic_write_max(ip),
+ xfs_get_atomic_write_max_opt(ip));
}
STATIC int
diff --git a/fs/xfs/xfs_iops.h b/fs/xfs/xfs_iops.h
index 3c1a2605ffd2..0896f6b8b3b8 100644
--- a/fs/xfs/xfs_iops.h
+++ b/fs/xfs/xfs_iops.h
@@ -19,5 +19,8 @@ int xfs_inode_init_security(struct inode *inode, struct inode *dir,
extern void xfs_setup_inode(struct xfs_inode *ip);
extern void xfs_setup_iops(struct xfs_inode *ip);
extern void xfs_diflags_to_iflags(struct xfs_inode *ip, bool init);
+unsigned int xfs_get_atomic_write_min(struct xfs_inode *ip);
+unsigned int xfs_get_atomic_write_max(struct xfs_inode *ip);
+unsigned int xfs_get_atomic_write_max_opt(struct xfs_inode *ip);
#endif /* __XFS_IOPS_H__ */
--
2.31.1
^ permalink raw reply related
* [PATCH v12 09/17] xfs: refactor xfs_reflink_end_cow_extent()
From: John Garry @ 2025-05-06 9:04 UTC (permalink / raw)
To: brauner, djwong, hch, viro, jack, cem
Cc: linux-fsdevel, dchinner, linux-xfs, linux-kernel, ojaswin,
ritesh.list, martin.petersen, linux-ext4, linux-block,
catherine.hoang, linux-api, John Garry
In-Reply-To: <20250506090427.2549456-1-john.g.garry@oracle.com>
Refactor xfs_reflink_end_cow_extent() into separate parts which process
the CoW range and commit the transaction.
This refactoring will be used in future for when it is required to commit
a range of extents as a single transaction, similar to how it was done
pre-commit d6f215f359637.
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
fs/xfs/xfs_reflink.c | 72 ++++++++++++++++++++++++++------------------
1 file changed, 42 insertions(+), 30 deletions(-)
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index cc3b4df88110..bd711c5bb6bb 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -786,35 +786,19 @@ xfs_reflink_update_quota(
* requirements as low as possible.
*/
STATIC int
-xfs_reflink_end_cow_extent(
+xfs_reflink_end_cow_extent_locked(
+ struct xfs_trans *tp,
struct xfs_inode *ip,
xfs_fileoff_t *offset_fsb,
xfs_fileoff_t end_fsb)
{
struct xfs_iext_cursor icur;
struct xfs_bmbt_irec got, del, data;
- struct xfs_mount *mp = ip->i_mount;
- struct xfs_trans *tp;
struct xfs_ifork *ifp = xfs_ifork_ptr(ip, XFS_COW_FORK);
- unsigned int resblks;
int nmaps;
bool isrt = XFS_IS_REALTIME_INODE(ip);
int error;
- resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
- error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0,
- XFS_TRANS_RESERVE, &tp);
- if (error)
- return error;
-
- /*
- * Lock the inode. We have to ijoin without automatic unlock because
- * the lead transaction is the refcountbt record deletion; the data
- * fork update follows as a deferred log item.
- */
- xfs_ilock(ip, XFS_ILOCK_EXCL);
- xfs_trans_ijoin(tp, ip, 0);
-
/*
* In case of racing, overlapping AIO writes no COW extents might be
* left by the time I/O completes for the loser of the race. In that
@@ -823,7 +807,7 @@ xfs_reflink_end_cow_extent(
if (!xfs_iext_lookup_extent(ip, ifp, *offset_fsb, &icur, &got) ||
got.br_startoff >= end_fsb) {
*offset_fsb = end_fsb;
- goto out_cancel;
+ return 0;
}
/*
@@ -837,7 +821,7 @@ xfs_reflink_end_cow_extent(
if (!xfs_iext_next_extent(ifp, &icur, &got) ||
got.br_startoff >= end_fsb) {
*offset_fsb = end_fsb;
- goto out_cancel;
+ return 0;
}
}
del = got;
@@ -846,14 +830,14 @@ xfs_reflink_end_cow_extent(
error = xfs_iext_count_extend(tp, ip, XFS_DATA_FORK,
XFS_IEXT_REFLINK_END_COW_CNT);
if (error)
- goto out_cancel;
+ return error;
/* Grab the corresponding mapping in the data fork. */
nmaps = 1;
error = xfs_bmapi_read(ip, del.br_startoff, del.br_blockcount, &data,
&nmaps, 0);
if (error)
- goto out_cancel;
+ return error;
/* We can only remap the smaller of the two extent sizes. */
data.br_blockcount = min(data.br_blockcount, del.br_blockcount);
@@ -882,7 +866,7 @@ xfs_reflink_end_cow_extent(
error = xfs_bunmapi(NULL, ip, data.br_startoff,
data.br_blockcount, 0, 1, &done);
if (error)
- goto out_cancel;
+ return error;
ASSERT(done);
}
@@ -899,17 +883,45 @@ xfs_reflink_end_cow_extent(
/* Remove the mapping from the CoW fork. */
xfs_bmap_del_extent_cow(ip, &icur, &got, &del);
- error = xfs_trans_commit(tp);
- xfs_iunlock(ip, XFS_ILOCK_EXCL);
- if (error)
- return error;
-
/* Update the caller about how much progress we made. */
*offset_fsb = del.br_startoff + del.br_blockcount;
return 0;
+}
-out_cancel:
- xfs_trans_cancel(tp);
+/*
+ * Remap part of the CoW fork into the data fork.
+ *
+ * We aim to remap the range starting at @offset_fsb and ending at @end_fsb
+ * into the data fork; this function will remap what it can (at the end of the
+ * range) and update @end_fsb appropriately. Each remap gets its own
+ * transaction because we can end up merging and splitting bmbt blocks for
+ * every remap operation and we'd like to keep the block reservation
+ * requirements as low as possible.
+ */
+STATIC int
+xfs_reflink_end_cow_extent(
+ struct xfs_inode *ip,
+ xfs_fileoff_t *offset_fsb,
+ xfs_fileoff_t end_fsb)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_trans *tp;
+ unsigned int resblks;
+ int error;
+
+ resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
+ error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0,
+ XFS_TRANS_RESERVE, &tp);
+ if (error)
+ return error;
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ xfs_trans_ijoin(tp, ip, 0);
+
+ error = xfs_reflink_end_cow_extent_locked(tp, ip, offset_fsb, end_fsb);
+ if (error)
+ xfs_trans_cancel(tp);
+ else
+ error = xfs_trans_commit(tp);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
}
--
2.31.1
^ permalink raw reply related
* [PATCH v12 11/17] xfs: add xfs_atomic_write_cow_iomap_begin()
From: John Garry @ 2025-05-06 9:04 UTC (permalink / raw)
To: brauner, djwong, hch, viro, jack, cem
Cc: linux-fsdevel, dchinner, linux-xfs, linux-kernel, ojaswin,
ritesh.list, martin.petersen, linux-ext4, linux-block,
catherine.hoang, linux-api, John Garry
In-Reply-To: <20250506090427.2549456-1-john.g.garry@oracle.com>
For CoW-based atomic writes, reuse the infrastructure for reflink CoW fork
support.
Add ->iomap_begin() callback xfs_atomic_write_cow_iomap_begin() to create
staging mappings in the CoW fork for atomic write updates.
The general steps in the function are as follows:
- find extent mapping in the CoW fork for the FS block range being written
- if part or full extent is found, proceed to process found extent
- if no extent found, map in new blocks to the CoW fork
- convert unwritten blocks in extent if required
- update iomap extent mapping and return
The bulk of this function is quite similar to the processing in
xfs_reflink_allocate_cow(), where we try to find an extent mapping; if
none exists, then allocate a new extent in the CoW fork, convert unwritten
blocks, and return a mapping.
Performance testing has shown the XFS_ILOCK_EXCL locking to be quite
a bottleneck, so this is an area which could be optimised in future.
Christoph Hellwig contributed almost all of the code in
xfs_atomic_write_cow_iomap_begin().
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
[djwong: add a new xfs_can_sw_atomic_write to convey intent better]
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
fs/xfs/xfs_iomap.c | 128 +++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_iomap.h | 1 +
fs/xfs/xfs_mount.h | 5 ++
fs/xfs/xfs_reflink.c | 2 +-
fs/xfs/xfs_reflink.h | 2 +
fs/xfs/xfs_trace.h | 22 ++++++++
6 files changed, 159 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index cb23c8871f81..166fba2ff1ef 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1022,6 +1022,134 @@ const struct iomap_ops xfs_zoned_direct_write_iomap_ops = {
};
#endif /* CONFIG_XFS_RT */
+static int
+xfs_atomic_write_cow_iomap_begin(
+ struct inode *inode,
+ loff_t offset,
+ loff_t length,
+ unsigned flags,
+ struct iomap *iomap,
+ struct iomap *srcmap)
+{
+ struct xfs_inode *ip = XFS_I(inode);
+ struct xfs_mount *mp = ip->i_mount;
+ const xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
+ xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length);
+ xfs_filblks_t count_fsb = end_fsb - offset_fsb;
+ int nmaps = 1;
+ xfs_filblks_t resaligned;
+ struct xfs_bmbt_irec cmap;
+ struct xfs_iext_cursor icur;
+ struct xfs_trans *tp;
+ unsigned int dblocks = 0, rblocks = 0;
+ int error;
+ u64 seq;
+
+ ASSERT(flags & IOMAP_WRITE);
+ ASSERT(flags & IOMAP_DIRECT);
+
+ if (xfs_is_shutdown(mp))
+ return -EIO;
+
+ if (!xfs_can_sw_atomic_write(mp)) {
+ ASSERT(xfs_can_sw_atomic_write(mp));
+ return -EINVAL;
+ }
+
+ /* blocks are always allocated in this path */
+ if (flags & IOMAP_NOWAIT)
+ return -EAGAIN;
+
+ trace_xfs_iomap_atomic_write_cow(ip, offset, length);
+
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+
+ if (!ip->i_cowfp) {
+ ASSERT(!xfs_is_reflink_inode(ip));
+ xfs_ifork_init_cow(ip);
+ }
+
+ if (!xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &cmap))
+ cmap.br_startoff = end_fsb;
+ if (cmap.br_startoff <= offset_fsb) {
+ xfs_trim_extent(&cmap, offset_fsb, count_fsb);
+ goto found;
+ }
+
+ end_fsb = cmap.br_startoff;
+ count_fsb = end_fsb - offset_fsb;
+
+ resaligned = xfs_aligned_fsb_count(offset_fsb, count_fsb,
+ xfs_get_cowextsz_hint(ip));
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+ if (XFS_IS_REALTIME_INODE(ip)) {
+ dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
+ rblocks = resaligned;
+ } else {
+ dblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
+ rblocks = 0;
+ }
+
+ error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, dblocks,
+ rblocks, false, &tp);
+ if (error)
+ return error;
+
+ /* extent layout could have changed since the unlock, so check again */
+ if (!xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &cmap))
+ cmap.br_startoff = end_fsb;
+ if (cmap.br_startoff <= offset_fsb) {
+ xfs_trim_extent(&cmap, offset_fsb, count_fsb);
+ xfs_trans_cancel(tp);
+ goto found;
+ }
+
+ /*
+ * Allocate the entire reservation as unwritten blocks.
+ *
+ * Use XFS_BMAPI_EXTSZALIGN to hint at aligning new extents according to
+ * extszhint, such that there will be a greater chance that future
+ * atomic writes to that same range will be aligned (and don't require
+ * this COW-based method).
+ */
+ error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb,
+ XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC |
+ XFS_BMAPI_EXTSZALIGN, 0, &cmap, &nmaps);
+ if (error) {
+ xfs_trans_cancel(tp);
+ goto out_unlock;
+ }
+
+ xfs_inode_set_cowblocks_tag(ip);
+ error = xfs_trans_commit(tp);
+ if (error)
+ goto out_unlock;
+
+found:
+ if (cmap.br_state != XFS_EXT_NORM) {
+ error = xfs_reflink_convert_cow_locked(ip, offset_fsb,
+ count_fsb);
+ if (error)
+ goto out_unlock;
+ cmap.br_state = XFS_EXT_NORM;
+ }
+
+ length = XFS_FSB_TO_B(mp, cmap.br_startoff + cmap.br_blockcount);
+ trace_xfs_iomap_found(ip, offset, length - offset, XFS_COW_FORK, &cmap);
+ seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, IOMAP_F_SHARED, seq);
+
+out_unlock:
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ return error;
+}
+
+const struct iomap_ops xfs_atomic_write_cow_iomap_ops = {
+ .iomap_begin = xfs_atomic_write_cow_iomap_begin,
+};
+
static int
xfs_dax_write_iomap_end(
struct inode *inode,
diff --git a/fs/xfs/xfs_iomap.h b/fs/xfs/xfs_iomap.h
index d330c4a581b1..674f8ac1b9bd 100644
--- a/fs/xfs/xfs_iomap.h
+++ b/fs/xfs/xfs_iomap.h
@@ -56,5 +56,6 @@ extern const struct iomap_ops xfs_read_iomap_ops;
extern const struct iomap_ops xfs_seek_iomap_ops;
extern const struct iomap_ops xfs_xattr_iomap_ops;
extern const struct iomap_ops xfs_dax_write_iomap_ops;
+extern const struct iomap_ops xfs_atomic_write_cow_iomap_ops;
#endif /* __XFS_IOMAP_H__*/
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index e5192c12e7ac..e67bc3e91f98 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -464,6 +464,11 @@ static inline bool xfs_has_nonzoned(const struct xfs_mount *mp)
return !xfs_has_zoned(mp);
}
+static inline bool xfs_can_sw_atomic_write(struct xfs_mount *mp)
+{
+ return xfs_has_reflink(mp);
+}
+
/*
* Some features are always on for v5 file systems, allow the compiler to
* eliminiate dead code when building without v4 support.
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index bd711c5bb6bb..f5d338916098 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -293,7 +293,7 @@ xfs_bmap_trim_cow(
return xfs_reflink_trim_around_shared(ip, imap, shared);
}
-static int
+int
xfs_reflink_convert_cow_locked(
struct xfs_inode *ip,
xfs_fileoff_t offset_fsb,
diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h
index cc4e92278279..379619f24247 100644
--- a/fs/xfs/xfs_reflink.h
+++ b/fs/xfs/xfs_reflink.h
@@ -35,6 +35,8 @@ int xfs_reflink_allocate_cow(struct xfs_inode *ip, struct xfs_bmbt_irec *imap,
bool convert_now);
extern int xfs_reflink_convert_cow(struct xfs_inode *ip, xfs_off_t offset,
xfs_off_t count);
+int xfs_reflink_convert_cow_locked(struct xfs_inode *ip,
+ xfs_fileoff_t offset_fsb, xfs_filblks_t count_fsb);
extern int xfs_reflink_cancel_cow_blocks(struct xfs_inode *ip,
struct xfs_trans **tpp, xfs_fileoff_t offset_fsb,
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index e56ba1963160..9554578c6da4 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -1657,6 +1657,28 @@ DEFINE_RW_EVENT(xfs_file_direct_write);
DEFINE_RW_EVENT(xfs_file_dax_write);
DEFINE_RW_EVENT(xfs_reflink_bounce_dio_write);
+TRACE_EVENT(xfs_iomap_atomic_write_cow,
+ TP_PROTO(struct xfs_inode *ip, xfs_off_t offset, ssize_t count),
+ TP_ARGS(ip, offset, count),
+ TP_STRUCT__entry(
+ __field(dev_t, dev)
+ __field(xfs_ino_t, ino)
+ __field(xfs_off_t, offset)
+ __field(ssize_t, count)
+ ),
+ TP_fast_assign(
+ __entry->dev = VFS_I(ip)->i_sb->s_dev;
+ __entry->ino = ip->i_ino;
+ __entry->offset = offset;
+ __entry->count = count;
+ ),
+ TP_printk("dev %d:%d ino 0x%llx pos 0x%llx bytecount 0x%zx",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->ino,
+ __entry->offset,
+ __entry->count)
+)
+
DECLARE_EVENT_CLASS(xfs_imap_class,
TP_PROTO(struct xfs_inode *ip, xfs_off_t offset, ssize_t count,
int whichfork, struct xfs_bmbt_irec *irec),
--
2.31.1
^ permalink raw reply related
* [PATCH v12 12/17] xfs: add large atomic writes checks in xfs_direct_write_iomap_begin()
From: John Garry @ 2025-05-06 9:04 UTC (permalink / raw)
To: brauner, djwong, hch, viro, jack, cem
Cc: linux-fsdevel, dchinner, linux-xfs, linux-kernel, ojaswin,
ritesh.list, martin.petersen, linux-ext4, linux-block,
catherine.hoang, linux-api, John Garry
In-Reply-To: <20250506090427.2549456-1-john.g.garry@oracle.com>
For when large atomic writes (> 1x FS block) are supported, there will be
various occasions when HW offload may not be possible.
Such instances include:
- unaligned extent mapping wrt write length
- extent mappings which do not cover the full write, e.g. the write spans
sparse or mixed-mapping extents
- the write length is greater than HW offload can support
- no hardware support at all
In those cases, we need to fallback to the CoW-based atomic write mode. For
this, report special code -ENOPROTOOPT to inform the caller that HW
offload-based method is not possible.
In addition to the occasions mentioned, if the write covers an unallocated
range, we again judge that we need to rely on the CoW-based method when we
would need to allocate anything more than 1x block. This is because if we
allocate less blocks that is required for the write, then again HW
offload-based method would not be possible. So we are taking a pessimistic
approach to writes covering unallocated space.
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
[djwong: various cleanups]
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
fs/xfs/xfs_iomap.c | 62 ++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 60 insertions(+), 2 deletions(-)
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 166fba2ff1ef..ff05e6b1b0bb 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -798,6 +798,38 @@ imap_spans_range(
return true;
}
+static bool
+xfs_bmap_hw_atomic_write_possible(
+ struct xfs_inode *ip,
+ struct xfs_bmbt_irec *imap,
+ xfs_fileoff_t offset_fsb,
+ xfs_fileoff_t end_fsb)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ xfs_fsize_t len = XFS_FSB_TO_B(mp, end_fsb - offset_fsb);
+
+ /*
+ * atomic writes are required to be naturally aligned for disk blocks,
+ * which ensures that we adhere to block layer rules that we won't
+ * straddle any boundary or violate write alignment requirement.
+ */
+ if (!IS_ALIGNED(imap->br_startblock, imap->br_blockcount))
+ return false;
+
+ /*
+ * Spanning multiple extents would mean that multiple BIOs would be
+ * issued, and so would lose atomicity required for REQ_ATOMIC-based
+ * atomics.
+ */
+ if (!imap_spans_range(imap, offset_fsb, end_fsb))
+ return false;
+
+ /*
+ * The ->iomap_begin caller should ensure this, but check anyway.
+ */
+ return len <= xfs_inode_buftarg(ip)->bt_bdev_awu_max;
+}
+
static int
xfs_direct_write_iomap_begin(
struct inode *inode,
@@ -812,9 +844,11 @@ xfs_direct_write_iomap_begin(
struct xfs_bmbt_irec imap, cmap;
xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length);
+ xfs_fileoff_t orig_end_fsb = end_fsb;
int nimaps = 1, error = 0;
bool shared = false;
u16 iomap_flags = 0;
+ bool needs_alloc;
unsigned int lockmode;
u64 seq;
@@ -875,13 +909,37 @@ xfs_direct_write_iomap_begin(
(flags & IOMAP_DIRECT) || IS_DAX(inode));
if (error)
goto out_unlock;
- if (shared)
+ if (shared) {
+ if ((flags & IOMAP_ATOMIC) &&
+ !xfs_bmap_hw_atomic_write_possible(ip, &cmap,
+ offset_fsb, end_fsb)) {
+ error = -ENOPROTOOPT;
+ goto out_unlock;
+ }
goto out_found_cow;
+ }
end_fsb = imap.br_startoff + imap.br_blockcount;
length = XFS_FSB_TO_B(mp, end_fsb) - offset;
}
- if (imap_needs_alloc(inode, flags, &imap, nimaps))
+ needs_alloc = imap_needs_alloc(inode, flags, &imap, nimaps);
+
+ if (flags & IOMAP_ATOMIC) {
+ error = -ENOPROTOOPT;
+ /*
+ * If we allocate less than what is required for the write
+ * then we may end up with multiple extents, which means that
+ * REQ_ATOMIC-based cannot be used, so avoid this possibility.
+ */
+ if (needs_alloc && orig_end_fsb - offset_fsb > 1)
+ goto out_unlock;
+
+ if (!xfs_bmap_hw_atomic_write_possible(ip, &imap, offset_fsb,
+ orig_end_fsb))
+ goto out_unlock;
+ }
+
+ if (needs_alloc)
goto allocate_blocks;
/*
--
2.31.1
^ permalink raw reply related
* [PATCH v12 13/17] xfs: commit CoW-based atomic writes atomically
From: John Garry @ 2025-05-06 9:04 UTC (permalink / raw)
To: brauner, djwong, hch, viro, jack, cem
Cc: linux-fsdevel, dchinner, linux-xfs, linux-kernel, ojaswin,
ritesh.list, martin.petersen, linux-ext4, linux-block,
catherine.hoang, linux-api, John Garry
In-Reply-To: <20250506090427.2549456-1-john.g.garry@oracle.com>
When completing a CoW-based write, each extent range mapping update is
covered by a separate transaction.
For a CoW-based atomic write, all mappings must be changed at once, so
change to use a single transaction.
Note that there is a limit on the amount of log intent items which can be
fit into a single transaction, but this is being ignored for now since
the count of items for a typical atomic write would be much less than is
typically supported. A typical atomic write would be expected to be 64KB
or less, which means only 16 possible extents unmaps, which is quite
small.
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
[djwong: add tr_atomic_ioend]
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
fs/xfs/libxfs/xfs_log_rlimit.c | 4 +++
fs/xfs/libxfs/xfs_trans_resv.c | 15 +++++++++
fs/xfs/libxfs/xfs_trans_resv.h | 1 +
fs/xfs/xfs_file.c | 5 ++-
fs/xfs/xfs_reflink.c | 56 ++++++++++++++++++++++++++++++++++
fs/xfs/xfs_reflink.h | 2 ++
6 files changed, 82 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/libxfs/xfs_log_rlimit.c b/fs/xfs/libxfs/xfs_log_rlimit.c
index d3bd6a86c8fe..34bba96d30ca 100644
--- a/fs/xfs/libxfs/xfs_log_rlimit.c
+++ b/fs/xfs/libxfs/xfs_log_rlimit.c
@@ -91,6 +91,7 @@ xfs_log_calc_trans_resv_for_minlogblocks(
*/
if (xfs_want_minlogsize_fixes(&mp->m_sb)) {
xfs_trans_resv_calc(mp, resv);
+ resv->tr_atomic_ioend = M_RES(mp)->tr_atomic_ioend;
return;
}
@@ -107,6 +108,9 @@ xfs_log_calc_trans_resv_for_minlogblocks(
xfs_trans_resv_calc(mp, resv);
+ /* Copy the dynamic transaction reservation types from the running fs */
+ resv->tr_atomic_ioend = M_RES(mp)->tr_atomic_ioend;
+
if (xfs_has_reflink(mp)) {
/*
* In the early days of reflink, typical log operation counts
diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c
index 580d00ae2857..a841432abf83 100644
--- a/fs/xfs/libxfs/xfs_trans_resv.c
+++ b/fs/xfs/libxfs/xfs_trans_resv.c
@@ -1284,6 +1284,15 @@ xfs_calc_namespace_reservations(
resp->tr_mkdir.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
}
+STATIC void
+xfs_calc_default_atomic_ioend_reservation(
+ struct xfs_mount *mp,
+ struct xfs_trans_resv *resp)
+{
+ /* Pick a default that will scale reasonably for the log size. */
+ resp->tr_atomic_ioend = resp->tr_itruncate;
+}
+
void
xfs_trans_resv_calc(
struct xfs_mount *mp,
@@ -1378,4 +1387,10 @@ xfs_trans_resv_calc(
resp->tr_itruncate.tr_logcount += logcount_adj;
resp->tr_write.tr_logcount += logcount_adj;
resp->tr_qm_dqalloc.tr_logcount += logcount_adj;
+
+ /*
+ * Now that we've finished computing the static reservations, we can
+ * compute the dynamic reservation for atomic writes.
+ */
+ xfs_calc_default_atomic_ioend_reservation(mp, resp);
}
diff --git a/fs/xfs/libxfs/xfs_trans_resv.h b/fs/xfs/libxfs/xfs_trans_resv.h
index d9d0032cbbc5..670045d417a6 100644
--- a/fs/xfs/libxfs/xfs_trans_resv.h
+++ b/fs/xfs/libxfs/xfs_trans_resv.h
@@ -48,6 +48,7 @@ struct xfs_trans_resv {
struct xfs_trans_res tr_qm_dqalloc; /* allocate quota on disk */
struct xfs_trans_res tr_sb; /* modify superblock */
struct xfs_trans_res tr_fsyncts; /* update timestamps on fsync */
+ struct xfs_trans_res tr_atomic_ioend; /* untorn write completion */
};
/* shorthand way of accessing reservation structure */
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index e8acd6ca8f27..32883ec8ca2e 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -576,7 +576,10 @@ xfs_dio_write_end_io(
nofs_flag = memalloc_nofs_save();
if (flags & IOMAP_DIO_COW) {
- error = xfs_reflink_end_cow(ip, offset, size);
+ if (iocb->ki_flags & IOCB_ATOMIC)
+ error = xfs_reflink_end_atomic_cow(ip, offset, size);
+ else
+ error = xfs_reflink_end_cow(ip, offset, size);
if (error)
goto out;
}
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index f5d338916098..218dee76768b 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -984,6 +984,62 @@ xfs_reflink_end_cow(
return error;
}
+/*
+ * Fully remap all of the file's data fork at once, which is the critical part
+ * in achieving atomic behaviour.
+ * The regular CoW end path does not use function as to keep the block
+ * reservation per transaction as low as possible.
+ */
+int
+xfs_reflink_end_atomic_cow(
+ struct xfs_inode *ip,
+ xfs_off_t offset,
+ xfs_off_t count)
+{
+ xfs_fileoff_t offset_fsb;
+ xfs_fileoff_t end_fsb;
+ int error = 0;
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_trans *tp;
+ unsigned int resblks;
+
+ trace_xfs_reflink_end_cow(ip, offset, count);
+
+ offset_fsb = XFS_B_TO_FSBT(mp, offset);
+ end_fsb = XFS_B_TO_FSB(mp, offset + count);
+
+ /*
+ * Each remapping operation could cause a btree split, so in the worst
+ * case that's one for each block.
+ */
+ resblks = (end_fsb - offset_fsb) *
+ XFS_NEXTENTADD_SPACE_RES(mp, 1, XFS_DATA_FORK);
+
+ error = xfs_trans_alloc(mp, &M_RES(mp)->tr_atomic_ioend, resblks, 0,
+ XFS_TRANS_RESERVE, &tp);
+ if (error)
+ return error;
+
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ xfs_trans_ijoin(tp, ip, 0);
+
+ while (end_fsb > offset_fsb && !error) {
+ error = xfs_reflink_end_cow_extent_locked(tp, ip, &offset_fsb,
+ end_fsb);
+ }
+ if (error) {
+ trace_xfs_reflink_end_cow_error(ip, error, _RET_IP_);
+ goto out_cancel;
+ }
+ error = xfs_trans_commit(tp);
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ return error;
+out_cancel:
+ xfs_trans_cancel(tp);
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ return error;
+}
+
/*
* Free all CoW staging blocks that are still referenced by the ondisk refcount
* metadata. The ondisk metadata does not track which inode created the
diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h
index 379619f24247..412e9b6f2082 100644
--- a/fs/xfs/xfs_reflink.h
+++ b/fs/xfs/xfs_reflink.h
@@ -45,6 +45,8 @@ extern int xfs_reflink_cancel_cow_range(struct xfs_inode *ip, xfs_off_t offset,
xfs_off_t count, bool cancel_real);
extern int xfs_reflink_end_cow(struct xfs_inode *ip, xfs_off_t offset,
xfs_off_t count);
+int xfs_reflink_end_atomic_cow(struct xfs_inode *ip, xfs_off_t offset,
+ xfs_off_t count);
extern int xfs_reflink_recover_cow(struct xfs_mount *mp);
extern loff_t xfs_reflink_remap_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out, loff_t len,
--
2.31.1
^ permalink raw reply related
* [PATCH v12 17/17] xfs: allow sysadmins to specify a maximum atomic write limit at mount time
From: John Garry @ 2025-05-06 9:04 UTC (permalink / raw)
To: brauner, djwong, hch, viro, jack, cem
Cc: linux-fsdevel, dchinner, linux-xfs, linux-kernel, ojaswin,
ritesh.list, martin.petersen, linux-ext4, linux-block,
catherine.hoang, linux-api, John Garry
In-Reply-To: <20250506090427.2549456-1-john.g.garry@oracle.com>
From: "Darrick J. Wong" <djwong@kernel.org>
Introduce a mount option to allow sysadmins to specify the maximum size
of an atomic write. If the filesystem can work with the supplied value,
that becomes the new guaranteed maximum.
The value mustn't be too big for the existing filesystem geometry (max
write size, max AG/rtgroup size). We dynamically recompute the
tr_atomic_write transaction reservation based on the given block size,
check that the current log size isn't less than the new minimum log size
constraints, and set a new maximum.
The actual software atomic write max is still computed based off of
tr_atomic_ioend the same way it has for the past few commits. Note also
that xfs_calc_atomic_write_log_geometry is non-static because mkfs will
need that.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
Documentation/admin-guide/xfs.rst | 11 +++++
fs/xfs/libxfs/xfs_trans_resv.c | 69 ++++++++++++++++++++++++++
fs/xfs/libxfs/xfs_trans_resv.h | 4 ++
fs/xfs/xfs_mount.c | 80 ++++++++++++++++++++++++++++++-
fs/xfs/xfs_mount.h | 6 +++
fs/xfs/xfs_super.c | 58 +++++++++++++++++++++-
fs/xfs/xfs_trace.h | 33 +++++++++++++
7 files changed, 259 insertions(+), 2 deletions(-)
diff --git a/Documentation/admin-guide/xfs.rst b/Documentation/admin-guide/xfs.rst
index 5becb441c3cb..a18328a5fb93 100644
--- a/Documentation/admin-guide/xfs.rst
+++ b/Documentation/admin-guide/xfs.rst
@@ -151,6 +151,17 @@ When mounting an XFS filesystem, the following options are accepted.
optional, and the log section can be separate from the data
section or contained within it.
+ max_atomic_write=value
+ Set the maximum size of an atomic write. The size may be
+ specified in bytes, in kilobytes with a "k" suffix, in megabytes
+ with a "m" suffix, or in gigabytes with a "g" suffix. The size
+ cannot be larger than the maximum write size, larger than the
+ size of any allocation group, or larger than the size of a
+ remapping operation that the log can complete atomically.
+
+ The default value is to set the maximum I/O completion size
+ to allow each CPU to handle one at a time.
+
max_open_zones=value
Specify the max number of zones to keep open for writing on a
zoned rt device. Many open zones aids file data separation
diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c
index e73c09fbd24c..86a111d0f2fc 100644
--- a/fs/xfs/libxfs/xfs_trans_resv.c
+++ b/fs/xfs/libxfs/xfs_trans_resv.c
@@ -1488,3 +1488,72 @@ xfs_calc_max_atomic_write_fsblocks(
return ret;
}
+
+/*
+ * Compute the log blocks and transaction reservation needed to complete an
+ * atomic write of a given number of blocks. Worst case, each block requires
+ * separate handling. A return value of 0 means something went wrong.
+ */
+xfs_extlen_t
+xfs_calc_atomic_write_log_geometry(
+ struct xfs_mount *mp,
+ xfs_extlen_t blockcount,
+ unsigned int *new_logres)
+{
+ struct xfs_trans_res *curr_res = &M_RES(mp)->tr_atomic_ioend;
+ uint old_logres = curr_res->tr_logres;
+ unsigned int per_intent, step_size;
+ unsigned int logres;
+ xfs_extlen_t min_logblocks;
+
+ ASSERT(blockcount > 0);
+
+ xfs_calc_default_atomic_ioend_reservation(mp, M_RES(mp));
+
+ per_intent = xfs_calc_atomic_write_ioend_geometry(mp, &step_size);
+
+ /* Check for overflows */
+ if (check_mul_overflow(blockcount, per_intent, &logres) ||
+ check_add_overflow(logres, step_size, &logres))
+ return 0;
+
+ curr_res->tr_logres = logres;
+ min_logblocks = xfs_log_calc_minimum_size(mp);
+ curr_res->tr_logres = old_logres;
+
+ trace_xfs_calc_max_atomic_write_log_geometry(mp, per_intent, step_size,
+ blockcount, min_logblocks, logres);
+
+ *new_logres = logres;
+ return min_logblocks;
+}
+
+/*
+ * Compute the transaction reservation needed to complete an out of place
+ * atomic write of a given number of blocks.
+ */
+int
+xfs_calc_atomic_write_reservation(
+ struct xfs_mount *mp,
+ xfs_extlen_t blockcount)
+{
+ unsigned int new_logres;
+ xfs_extlen_t min_logblocks;
+
+ /*
+ * If the caller doesn't ask for a specific atomic write size, then
+ * use the defaults.
+ */
+ if (blockcount == 0) {
+ xfs_calc_default_atomic_ioend_reservation(mp, M_RES(mp));
+ return 0;
+ }
+
+ min_logblocks = xfs_calc_atomic_write_log_geometry(mp, blockcount,
+ &new_logres);
+ if (!min_logblocks || min_logblocks > mp->m_sb.sb_logblocks)
+ return -EINVAL;
+
+ M_RES(mp)->tr_atomic_ioend.tr_logres = new_logres;
+ return 0;
+}
diff --git a/fs/xfs/libxfs/xfs_trans_resv.h b/fs/xfs/libxfs/xfs_trans_resv.h
index a6d303b83688..336279e0fc61 100644
--- a/fs/xfs/libxfs/xfs_trans_resv.h
+++ b/fs/xfs/libxfs/xfs_trans_resv.h
@@ -122,5 +122,9 @@ unsigned int xfs_calc_write_reservation_minlogsize(struct xfs_mount *mp);
unsigned int xfs_calc_qm_dqalloc_reservation_minlogsize(struct xfs_mount *mp);
xfs_extlen_t xfs_calc_max_atomic_write_fsblocks(struct xfs_mount *mp);
+xfs_extlen_t xfs_calc_atomic_write_log_geometry(struct xfs_mount *mp,
+ xfs_extlen_t blockcount, unsigned int *new_logres);
+int xfs_calc_atomic_write_reservation(struct xfs_mount *mp,
+ xfs_extlen_t blockcount);
#endif /* __XFS_TRANS_RESV_H__ */
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 86089e27b8e7..29276fe60df9 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -742,6 +742,82 @@ xfs_calc_atomic_write_unit_max(
max_agsize, max_rgsize);
}
+/*
+ * Try to set the atomic write maximum to a new value that we got from
+ * userspace via mount option.
+ */
+int
+xfs_set_max_atomic_write_opt(
+ struct xfs_mount *mp,
+ unsigned long long new_max_bytes)
+{
+ const xfs_filblks_t new_max_fsbs = XFS_B_TO_FSBT(mp, new_max_bytes);
+ const xfs_extlen_t max_write = xfs_calc_atomic_write_max(mp);
+ const xfs_extlen_t max_group =
+ max(mp->m_groups[XG_TYPE_AG].blocks,
+ mp->m_groups[XG_TYPE_RTG].blocks);
+ const xfs_extlen_t max_group_write =
+ max(xfs_calc_perag_awu_max(mp), xfs_calc_rtgroup_awu_max(mp));
+ int error;
+
+ if (new_max_bytes == 0)
+ goto set_limit;
+
+ ASSERT(max_write <= U32_MAX);
+
+ /* generic_atomic_write_valid enforces power of two length */
+ if (!is_power_of_2(new_max_bytes)) {
+ xfs_warn(mp,
+ "max atomic write size of %llu bytes is not a power of 2",
+ new_max_bytes);
+ return -EINVAL;
+ }
+
+ if (new_max_bytes & mp->m_blockmask) {
+ xfs_warn(mp,
+ "max atomic write size of %llu bytes not aligned with fsblock",
+ new_max_bytes);
+ return -EINVAL;
+ }
+
+ if (new_max_fsbs > max_write) {
+ xfs_warn(mp,
+ "max atomic write size of %lluk cannot be larger than max write size %lluk",
+ new_max_bytes >> 10,
+ XFS_FSB_TO_B(mp, max_write) >> 10);
+ return -EINVAL;
+ }
+
+ if (new_max_fsbs > max_group) {
+ xfs_warn(mp,
+ "max atomic write size of %lluk cannot be larger than allocation group size %lluk",
+ new_max_bytes >> 10,
+ XFS_FSB_TO_B(mp, max_group) >> 10);
+ return -EINVAL;
+ }
+
+ if (new_max_fsbs > max_group_write) {
+ xfs_warn(mp,
+ "max atomic write size of %lluk cannot be larger than max allocation group write size %lluk",
+ new_max_bytes >> 10,
+ XFS_FSB_TO_B(mp, max_group_write) >> 10);
+ return -EINVAL;
+ }
+
+set_limit:
+ error = xfs_calc_atomic_write_reservation(mp, new_max_fsbs);
+ if (error) {
+ xfs_warn(mp,
+ "cannot support completing atomic writes of %lluk",
+ new_max_bytes >> 10);
+ return error;
+ }
+
+ xfs_calc_atomic_write_unit_max(mp);
+ mp->m_awu_max_bytes = new_max_bytes;
+ return 0;
+}
+
/* Compute maximum possible height for realtime btree types for this fs. */
static inline void
xfs_rtbtree_compute_maxlevels(
@@ -1163,7 +1239,9 @@ xfs_mountfs(
* derived from transaction reservations, so we must do this after the
* log is fully initialized.
*/
- xfs_calc_atomic_write_unit_max(mp);
+ error = xfs_set_max_atomic_write_opt(mp, mp->m_awu_max_bytes);
+ if (error)
+ goto out_agresv;
return 0;
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index e2abf31438e0..5b5df70570c0 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -237,6 +237,9 @@ typedef struct xfs_mount {
unsigned int m_max_open_zones;
unsigned int m_zonegc_low_space;
+ /* max_atomic_write mount option value */
+ unsigned long long m_awu_max_bytes;
+
/*
* Bitsets of per-fs metadata that have been checked and/or are sick.
* Callers must hold m_sb_lock to access these two fields.
@@ -804,4 +807,7 @@ static inline void xfs_mod_sb_delalloc(struct xfs_mount *mp, int64_t delta)
percpu_counter_add(&mp->m_delalloc_blks, delta);
}
+int xfs_set_max_atomic_write_opt(struct xfs_mount *mp,
+ unsigned long long new_max_bytes);
+
#endif /* __XFS_MOUNT_H__ */
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 77a3c003fc4f..8e3ae1749855 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -111,7 +111,7 @@ enum {
Opt_prjquota, Opt_uquota, Opt_gquota, Opt_pquota,
Opt_uqnoenforce, Opt_gqnoenforce, Opt_pqnoenforce, Opt_qnoenforce,
Opt_discard, Opt_nodiscard, Opt_dax, Opt_dax_enum, Opt_max_open_zones,
- Opt_lifetime, Opt_nolifetime,
+ Opt_lifetime, Opt_nolifetime, Opt_max_atomic_write,
};
static const struct fs_parameter_spec xfs_fs_parameters[] = {
@@ -159,6 +159,7 @@ static const struct fs_parameter_spec xfs_fs_parameters[] = {
fsparam_u32("max_open_zones", Opt_max_open_zones),
fsparam_flag("lifetime", Opt_lifetime),
fsparam_flag("nolifetime", Opt_nolifetime),
+ fsparam_string("max_atomic_write", Opt_max_atomic_write),
{}
};
@@ -241,6 +242,9 @@ xfs_fs_show_options(
if (mp->m_max_open_zones)
seq_printf(m, ",max_open_zones=%u", mp->m_max_open_zones);
+ if (mp->m_awu_max_bytes)
+ seq_printf(m, ",max_atomic_write=%lluk",
+ mp->m_awu_max_bytes >> 10);
return 0;
}
@@ -1343,6 +1347,42 @@ suffix_kstrtoint(
return ret;
}
+static int
+suffix_kstrtoull(
+ const char *s,
+ unsigned int base,
+ unsigned long long *res)
+{
+ int last, shift_left_factor = 0;
+ unsigned long long _res;
+ char *value;
+ int ret = 0;
+
+ value = kstrdup(s, GFP_KERNEL);
+ if (!value)
+ return -ENOMEM;
+
+ last = strlen(value) - 1;
+ if (value[last] == 'K' || value[last] == 'k') {
+ shift_left_factor = 10;
+ value[last] = '\0';
+ }
+ if (value[last] == 'M' || value[last] == 'm') {
+ shift_left_factor = 20;
+ value[last] = '\0';
+ }
+ if (value[last] == 'G' || value[last] == 'g') {
+ shift_left_factor = 30;
+ value[last] = '\0';
+ }
+
+ if (kstrtoull(value, base, &_res))
+ ret = -EINVAL;
+ kfree(value);
+ *res = _res << shift_left_factor;
+ return ret;
+}
+
static inline void
xfs_fs_warn_deprecated(
struct fs_context *fc,
@@ -1527,6 +1567,14 @@ xfs_fs_parse_param(
case Opt_nolifetime:
parsing_mp->m_features |= XFS_FEAT_NOLIFETIME;
return 0;
+ case Opt_max_atomic_write:
+ if (suffix_kstrtoull(param->string, 10,
+ &parsing_mp->m_awu_max_bytes)) {
+ xfs_warn(parsing_mp,
+ "max atomic write size must be positive integer");
+ return -EINVAL;
+ }
+ return 0;
default:
xfs_warn(parsing_mp, "unknown mount option [%s].", param->key);
return -EINVAL;
@@ -2137,6 +2185,14 @@ xfs_fs_reconfigure(
if (error)
return error;
+ /* Validate new max_atomic_write option before making other changes */
+ if (mp->m_awu_max_bytes != new_mp->m_awu_max_bytes) {
+ error = xfs_set_max_atomic_write_opt(mp,
+ new_mp->m_awu_max_bytes);
+ if (error)
+ return error;
+ }
+
/* inode32 -> inode64 */
if (xfs_has_small_inums(mp) && !xfs_has_small_inums(new_mp)) {
mp->m_features &= ~XFS_FEAT_SMALL_INUMS;
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index d5ae00f8e04c..01d284a1c759 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -230,6 +230,39 @@ TRACE_EVENT(xfs_calc_max_atomic_write_fsblocks,
__entry->blockcount)
);
+TRACE_EVENT(xfs_calc_max_atomic_write_log_geometry,
+ TP_PROTO(struct xfs_mount *mp, unsigned int per_intent,
+ unsigned int step_size, unsigned int blockcount,
+ unsigned int min_logblocks, unsigned int logres),
+ TP_ARGS(mp, per_intent, step_size, blockcount, min_logblocks, logres),
+ TP_STRUCT__entry(
+ __field(dev_t, dev)
+ __field(unsigned int, per_intent)
+ __field(unsigned int, step_size)
+ __field(unsigned int, blockcount)
+ __field(unsigned int, min_logblocks)
+ __field(unsigned int, cur_logblocks)
+ __field(unsigned int, logres)
+ ),
+ TP_fast_assign(
+ __entry->dev = mp->m_super->s_dev;
+ __entry->per_intent = per_intent;
+ __entry->step_size = step_size;
+ __entry->blockcount = blockcount;
+ __entry->min_logblocks = min_logblocks;
+ __entry->cur_logblocks = mp->m_sb.sb_logblocks;
+ __entry->logres = logres;
+ ),
+ TP_printk("dev %d:%d per_intent %u step_size %u blockcount %u min_logblocks %u logblocks %u logres %u",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->per_intent,
+ __entry->step_size,
+ __entry->blockcount,
+ __entry->min_logblocks,
+ __entry->cur_logblocks,
+ __entry->logres)
+);
+
TRACE_EVENT(xlog_intent_recovery_failed,
TP_PROTO(struct xfs_mount *mp, const struct xfs_defer_op_type *ops,
int error),
--
2.31.1
^ permalink raw reply related
* [PATCH v12 14/17] xfs: add xfs_file_dio_write_atomic()
From: John Garry @ 2025-05-06 9:04 UTC (permalink / raw)
To: brauner, djwong, hch, viro, jack, cem
Cc: linux-fsdevel, dchinner, linux-xfs, linux-kernel, ojaswin,
ritesh.list, martin.petersen, linux-ext4, linux-block,
catherine.hoang, linux-api, John Garry
In-Reply-To: <20250506090427.2549456-1-john.g.garry@oracle.com>
Add xfs_file_dio_write_atomic() for dedicated handling of atomic writes.
Now HW offload will not be required to support atomic writes and is
an optional feature.
CoW-based atomic writes will be supported with out-of-places write and
atomic extent remapping.
Either mode of operation may be used for an atomic write, depending on the
circumstances.
The preferred method is HW offload as it will be faster. If HW offload is
not available then we always use the CoW-based method. If HW offload is
available but not possible to use, then again we use the CoW-based method.
If available, HW offload would not be possible for the write length
exceeding the HW offload limit, the write spanning multiple extents,
unaligned disk blocks, etc.
Apart from the write exceeding the HW offload limit, other conditions for
HW offload usage can only be detected in the iomap handling for the write.
As such, we use a fallback method to issue the write if we detect in the
->iomap_begin() handler that HW offload is not possible. Special code
-ENOPROTOOPT is returned from ->iomap_begin() to inform that HW offload is
not possible.
In other words, atomic writes are supported on any filesystem that can
perform out of place write remapping atomically (i.e. reflink) up to
some fairly large size. If the conditions are right (a single correctly
aligned overwrite mapping) then the filesystem will use any available
hardware support to avoid the filesystem metadata updates.
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
fs/xfs/xfs_file.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 68 insertions(+)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 32883ec8ca2e..f4a66ff85748 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -728,6 +728,72 @@ xfs_file_dio_write_zoned(
return ret;
}
+/*
+ * Handle block atomic writes
+ *
+ * Two methods of atomic writes are supported:
+ * - REQ_ATOMIC-based, which would typically use some form of HW offload in the
+ * disk
+ * - COW-based, which uses a COW fork as a staging extent for data updates
+ * before atomically updating extent mappings for the range being written
+ *
+ */
+static noinline ssize_t
+xfs_file_dio_write_atomic(
+ struct xfs_inode *ip,
+ struct kiocb *iocb,
+ struct iov_iter *from)
+{
+ unsigned int iolock = XFS_IOLOCK_SHARED;
+ ssize_t ret, ocount = iov_iter_count(from);
+ const struct iomap_ops *dops;
+
+ /*
+ * HW offload should be faster, so try that first if it is already
+ * known that the write length is not too large.
+ */
+ if (ocount > xfs_inode_buftarg(ip)->bt_bdev_awu_max)
+ dops = &xfs_atomic_write_cow_iomap_ops;
+ else
+ dops = &xfs_direct_write_iomap_ops;
+
+retry:
+ ret = xfs_ilock_iocb_for_write(iocb, &iolock);
+ if (ret)
+ return ret;
+
+ ret = xfs_file_write_checks(iocb, from, &iolock, NULL);
+ if (ret)
+ goto out_unlock;
+
+ /* Demote similar to xfs_file_dio_write_aligned() */
+ if (iolock == XFS_IOLOCK_EXCL) {
+ xfs_ilock_demote(ip, XFS_IOLOCK_EXCL);
+ iolock = XFS_IOLOCK_SHARED;
+ }
+
+ trace_xfs_file_direct_write(iocb, from);
+ ret = iomap_dio_rw(iocb, from, dops, &xfs_dio_write_ops,
+ 0, NULL, 0);
+
+ /*
+ * The retry mechanism is based on the ->iomap_begin method returning
+ * -ENOPROTOOPT, which would be when the REQ_ATOMIC-based write is not
+ * possible. The REQ_ATOMIC-based method typically not be possible if
+ * the write spans multiple extents or the disk blocks are misaligned.
+ */
+ if (ret == -ENOPROTOOPT && dops == &xfs_direct_write_iomap_ops) {
+ xfs_iunlock(ip, iolock);
+ dops = &xfs_atomic_write_cow_iomap_ops;
+ goto retry;
+ }
+
+out_unlock:
+ if (iolock)
+ xfs_iunlock(ip, iolock);
+ return ret;
+}
+
/*
* Handle block unaligned direct I/O writes
*
@@ -843,6 +909,8 @@ xfs_file_dio_write(
return xfs_file_dio_write_unaligned(ip, iocb, from);
if (xfs_is_zoned_inode(ip))
return xfs_file_dio_write_zoned(ip, iocb, from);
+ if (iocb->ki_flags & IOCB_ATOMIC)
+ return xfs_file_dio_write_atomic(ip, iocb, from);
return xfs_file_dio_write_aligned(ip, iocb, from,
&xfs_direct_write_iomap_ops, &xfs_dio_write_ops, NULL);
}
--
2.31.1
^ permalink raw reply related
* [PATCH v12 15/17] xfs: add xfs_calc_atomic_write_unit_max()
From: John Garry @ 2025-05-06 9:04 UTC (permalink / raw)
To: brauner, djwong, hch, viro, jack, cem
Cc: linux-fsdevel, dchinner, linux-xfs, linux-kernel, ojaswin,
ritesh.list, martin.petersen, linux-ext4, linux-block,
catherine.hoang, linux-api, John Garry
In-Reply-To: <20250506090427.2549456-1-john.g.garry@oracle.com>
Now that CoW-based atomic writes are supported, update the max size of an
atomic write for the data device.
The limit of a CoW-based atomic write will be the limit of the number of
logitems which can fit into a single transaction.
In addition, the max atomic write size needs to be aligned to the agsize.
Limit the size of atomic writes to the greatest power-of-two factor of the
agsize so that allocations for an atomic write will always be aligned
compatibly with the alignment requirements of the storage.
Function xfs_atomic_write_logitems() is added to find the limit the number
of log items which can fit in a single transaction.
Amend the max atomic write computation to create a new transaction
reservation type, and compute the maximum size of an atomic write
completion (in fsblocks) based on this new transaction reservation.
Initially, tr_atomic_write is a clone of tr_itruncate, which provides a
reasonable level of parallelism. In the next patch, we'll add a mount
option so that sysadmins can configure their own limits.
[djwong: use a new reservation type for atomic write ioends, refactor
group limit calculations]
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
[jpg: rounddown power-of-2 always]
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
fs/xfs/libxfs/xfs_trans_resv.c | 94 ++++++++++++++++++++++++++++++++++
fs/xfs/libxfs/xfs_trans_resv.h | 2 +
fs/xfs/xfs_mount.c | 83 ++++++++++++++++++++++++++++++
fs/xfs/xfs_mount.h | 6 +++
fs/xfs/xfs_reflink.c | 16 ++++++
fs/xfs/xfs_reflink.h | 2 +
fs/xfs/xfs_trace.h | 60 ++++++++++++++++++++++
7 files changed, 263 insertions(+)
diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c
index a841432abf83..e73c09fbd24c 100644
--- a/fs/xfs/libxfs/xfs_trans_resv.c
+++ b/fs/xfs/libxfs/xfs_trans_resv.c
@@ -22,6 +22,12 @@
#include "xfs_rtbitmap.h"
#include "xfs_attr_item.h"
#include "xfs_log.h"
+#include "xfs_defer.h"
+#include "xfs_bmap_item.h"
+#include "xfs_extfree_item.h"
+#include "xfs_rmap_item.h"
+#include "xfs_refcount_item.h"
+#include "xfs_trace.h"
#define _ALLOC true
#define _FREE false
@@ -1394,3 +1400,91 @@ xfs_trans_resv_calc(
*/
xfs_calc_default_atomic_ioend_reservation(mp, resp);
}
+
+/*
+ * Return the per-extent and fixed transaction reservation sizes needed to
+ * complete an atomic write.
+ */
+STATIC unsigned int
+xfs_calc_atomic_write_ioend_geometry(
+ struct xfs_mount *mp,
+ unsigned int *step_size)
+{
+ const unsigned int efi = xfs_efi_log_space(1);
+ const unsigned int efd = xfs_efd_log_space(1);
+ const unsigned int rui = xfs_rui_log_space(1);
+ const unsigned int rud = xfs_rud_log_space();
+ const unsigned int cui = xfs_cui_log_space(1);
+ const unsigned int cud = xfs_cud_log_space();
+ const unsigned int bui = xfs_bui_log_space(1);
+ const unsigned int bud = xfs_bud_log_space();
+
+ /*
+ * Maximum overhead to complete an atomic write ioend in software:
+ * remove data fork extent + remove cow fork extent + map extent into
+ * data fork.
+ *
+ * tx0: Creates a BUI and a CUI and that's all it needs.
+ *
+ * tx1: Roll to finish the BUI. Need space for the BUD, an RUI, and
+ * enough space to relog the CUI (== CUI + CUD).
+ *
+ * tx2: Roll again to finish the RUI. Need space for the RUD and space
+ * to relog the CUI.
+ *
+ * tx3: Roll again, need space for the CUD and possibly a new EFI.
+ *
+ * tx4: Roll again, need space for an EFD.
+ *
+ * If the extent referenced by the pair of BUI/CUI items is not the one
+ * being currently processed, then we need to reserve space to relog
+ * both items.
+ */
+ const unsigned int tx0 = bui + cui;
+ const unsigned int tx1 = bud + rui + cui + cud;
+ const unsigned int tx2 = rud + cui + cud;
+ const unsigned int tx3 = cud + efi;
+ const unsigned int tx4 = efd;
+ const unsigned int relog = bui + bud + cui + cud;
+
+ const unsigned int per_intent = max(max3(tx0, tx1, tx2),
+ max3(tx3, tx4, relog));
+
+ /* Overhead to finish one step of each intent item type */
+ const unsigned int f1 = xfs_calc_finish_efi_reservation(mp, 1);
+ const unsigned int f2 = xfs_calc_finish_rui_reservation(mp, 1);
+ const unsigned int f3 = xfs_calc_finish_cui_reservation(mp, 1);
+ const unsigned int f4 = xfs_calc_finish_bui_reservation(mp, 1);
+
+ /* We only finish one item per transaction in a chain */
+ *step_size = max(f4, max3(f1, f2, f3));
+
+ return per_intent;
+}
+
+/*
+ * Compute the maximum size (in fsblocks) of atomic writes that we can complete
+ * given the existing log reservations.
+ */
+xfs_extlen_t
+xfs_calc_max_atomic_write_fsblocks(
+ struct xfs_mount *mp)
+{
+ const struct xfs_trans_res *resv = &M_RES(mp)->tr_atomic_ioend;
+ unsigned int per_intent = 0;
+ unsigned int step_size = 0;
+ unsigned int ret = 0;
+
+ if (resv->tr_logres > 0) {
+ per_intent = xfs_calc_atomic_write_ioend_geometry(mp,
+ &step_size);
+
+ if (resv->tr_logres >= step_size)
+ ret = (resv->tr_logres - step_size) / per_intent;
+ }
+
+ trace_xfs_calc_max_atomic_write_fsblocks(mp, per_intent, step_size,
+ resv->tr_logres, ret);
+
+ return ret;
+}
diff --git a/fs/xfs/libxfs/xfs_trans_resv.h b/fs/xfs/libxfs/xfs_trans_resv.h
index 670045d417a6..a6d303b83688 100644
--- a/fs/xfs/libxfs/xfs_trans_resv.h
+++ b/fs/xfs/libxfs/xfs_trans_resv.h
@@ -121,4 +121,6 @@ unsigned int xfs_calc_itruncate_reservation_minlogsize(struct xfs_mount *mp);
unsigned int xfs_calc_write_reservation_minlogsize(struct xfs_mount *mp);
unsigned int xfs_calc_qm_dqalloc_reservation_minlogsize(struct xfs_mount *mp);
+xfs_extlen_t xfs_calc_max_atomic_write_fsblocks(struct xfs_mount *mp);
+
#endif /* __XFS_TRANS_RESV_H__ */
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 00b53f479ece..86089e27b8e7 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -666,6 +666,82 @@ xfs_agbtree_compute_maxlevels(
mp->m_agbtree_maxlevels = max(levels, mp->m_refc_maxlevels);
}
+/* Maximum atomic write IO size that the kernel allows. */
+static inline xfs_extlen_t xfs_calc_atomic_write_max(struct xfs_mount *mp)
+{
+ return rounddown_pow_of_two(XFS_B_TO_FSB(mp, MAX_RW_COUNT));
+}
+
+static inline unsigned int max_pow_of_two_factor(const unsigned int nr)
+{
+ return 1 << (ffs(nr) - 1);
+}
+
+/*
+ * If the data device advertises atomic write support, limit the size of data
+ * device atomic writes to the greatest power-of-two factor of the AG size so
+ * that every atomic write unit aligns with the start of every AG. This is
+ * required so that the per-AG allocations for an atomic write will always be
+ * aligned compatibly with the alignment requirements of the storage.
+ *
+ * If the data device doesn't advertise atomic writes, then there are no
+ * alignment restrictions and the largest out-of-place write we can do
+ * ourselves is the number of blocks that user files can allocate from any AG.
+ */
+static inline xfs_extlen_t xfs_calc_perag_awu_max(struct xfs_mount *mp)
+{
+ if (mp->m_ddev_targp->bt_bdev_awu_min > 0)
+ return max_pow_of_two_factor(mp->m_sb.sb_agblocks);
+ return rounddown_pow_of_two(mp->m_ag_max_usable);
+}
+
+/*
+ * Reflink on the realtime device requires rtgroups, and atomic writes require
+ * reflink.
+ *
+ * If the realtime device advertises atomic write support, limit the size of
+ * data device atomic writes to the greatest power-of-two factor of the rtgroup
+ * size so that every atomic write unit aligns with the start of every rtgroup.
+ * This is required so that the per-rtgroup allocations for an atomic write
+ * will always be aligned compatibly with the alignment requirements of the
+ * storage.
+ *
+ * If the rt device doesn't advertise atomic writes, then there are no
+ * alignment restrictions and the largest out-of-place write we can do
+ * ourselves is the number of blocks that user files can allocate from any
+ * rtgroup.
+ */
+static inline xfs_extlen_t xfs_calc_rtgroup_awu_max(struct xfs_mount *mp)
+{
+ struct xfs_groups *rgs = &mp->m_groups[XG_TYPE_RTG];
+
+ if (rgs->blocks == 0)
+ return 0;
+ if (mp->m_rtdev_targp && mp->m_rtdev_targp->bt_bdev_awu_min > 0)
+ return max_pow_of_two_factor(rgs->blocks);
+ return rounddown_pow_of_two(rgs->blocks);
+}
+
+/* Compute the maximum atomic write unit size for each section. */
+static inline void
+xfs_calc_atomic_write_unit_max(
+ struct xfs_mount *mp)
+{
+ struct xfs_groups *ags = &mp->m_groups[XG_TYPE_AG];
+ struct xfs_groups *rgs = &mp->m_groups[XG_TYPE_RTG];
+
+ const xfs_extlen_t max_write = xfs_calc_atomic_write_max(mp);
+ const xfs_extlen_t max_ioend = xfs_reflink_max_atomic_cow(mp);
+ const xfs_extlen_t max_agsize = xfs_calc_perag_awu_max(mp);
+ const xfs_extlen_t max_rgsize = xfs_calc_rtgroup_awu_max(mp);
+
+ ags->awu_max = min3(max_write, max_ioend, max_agsize);
+ rgs->awu_max = min3(max_write, max_ioend, max_rgsize);
+
+ trace_xfs_calc_atomic_write_unit_max(mp, max_write, max_ioend,
+ max_agsize, max_rgsize);
+}
+
/* Compute maximum possible height for realtime btree types for this fs. */
static inline void
xfs_rtbtree_compute_maxlevels(
@@ -1082,6 +1158,13 @@ xfs_mountfs(
xfs_zone_gc_start(mp);
}
+ /*
+ * Pre-calculate atomic write unit max. This involves computations
+ * derived from transaction reservations, so we must do this after the
+ * log is fully initialized.
+ */
+ xfs_calc_atomic_write_unit_max(mp);
+
return 0;
out_agresv:
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index e67bc3e91f98..e2abf31438e0 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -119,6 +119,12 @@ struct xfs_groups {
* SMR hard drives.
*/
xfs_fsblock_t start_fsb;
+
+ /*
+ * Maximum length of an atomic write for files stored in this
+ * collection of allocation groups, in fsblocks.
+ */
+ xfs_extlen_t awu_max;
};
struct xfs_freecounter {
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 218dee76768b..ad3bcb76d805 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1040,6 +1040,22 @@ xfs_reflink_end_atomic_cow(
return error;
}
+/* Compute the largest atomic write that we can complete through software. */
+xfs_extlen_t
+xfs_reflink_max_atomic_cow(
+ struct xfs_mount *mp)
+{
+ /* We cannot do any atomic writes without out of place writes. */
+ if (!xfs_can_sw_atomic_write(mp))
+ return 0;
+
+ /*
+ * Atomic write limits must always be a power-of-2, according to
+ * generic_atomic_write_valid.
+ */
+ return rounddown_pow_of_two(xfs_calc_max_atomic_write_fsblocks(mp));
+}
+
/*
* Free all CoW staging blocks that are still referenced by the ondisk refcount
* metadata. The ondisk metadata does not track which inode created the
diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h
index 412e9b6f2082..36cda724da89 100644
--- a/fs/xfs/xfs_reflink.h
+++ b/fs/xfs/xfs_reflink.h
@@ -68,4 +68,6 @@ extern int xfs_reflink_update_dest(struct xfs_inode *dest, xfs_off_t newlen,
bool xfs_reflink_supports_rextsize(struct xfs_mount *mp, unsigned int rextsize);
+xfs_extlen_t xfs_reflink_max_atomic_cow(struct xfs_mount *mp);
+
#endif /* __XFS_REFLINK_H */
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 9554578c6da4..d5ae00f8e04c 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -170,6 +170,66 @@ DEFINE_ATTR_LIST_EVENT(xfs_attr_list_notfound);
DEFINE_ATTR_LIST_EVENT(xfs_attr_leaf_list);
DEFINE_ATTR_LIST_EVENT(xfs_attr_node_list);
+TRACE_EVENT(xfs_calc_atomic_write_unit_max,
+ TP_PROTO(struct xfs_mount *mp, unsigned int max_write,
+ unsigned int max_ioend, unsigned int max_agsize,
+ unsigned int max_rgsize),
+ TP_ARGS(mp, max_write, max_ioend, max_agsize, max_rgsize),
+ TP_STRUCT__entry(
+ __field(dev_t, dev)
+ __field(unsigned int, max_write)
+ __field(unsigned int, max_ioend)
+ __field(unsigned int, max_agsize)
+ __field(unsigned int, max_rgsize)
+ __field(unsigned int, data_awu_max)
+ __field(unsigned int, rt_awu_max)
+ ),
+ TP_fast_assign(
+ __entry->dev = mp->m_super->s_dev;
+ __entry->max_write = max_write;
+ __entry->max_ioend = max_ioend;
+ __entry->max_agsize = max_agsize;
+ __entry->max_rgsize = max_rgsize;
+ __entry->data_awu_max = mp->m_groups[XG_TYPE_AG].awu_max;
+ __entry->rt_awu_max = mp->m_groups[XG_TYPE_RTG].awu_max;
+ ),
+ TP_printk("dev %d:%d max_write %u max_ioend %u max_agsize %u max_rgsize %u data_awu_max %u rt_awu_max %u",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->max_write,
+ __entry->max_ioend,
+ __entry->max_agsize,
+ __entry->max_rgsize,
+ __entry->data_awu_max,
+ __entry->rt_awu_max)
+);
+
+TRACE_EVENT(xfs_calc_max_atomic_write_fsblocks,
+ TP_PROTO(struct xfs_mount *mp, unsigned int per_intent,
+ unsigned int step_size, unsigned int logres,
+ unsigned int blockcount),
+ TP_ARGS(mp, per_intent, step_size, logres, blockcount),
+ TP_STRUCT__entry(
+ __field(dev_t, dev)
+ __field(unsigned int, per_intent)
+ __field(unsigned int, step_size)
+ __field(unsigned int, logres)
+ __field(unsigned int, blockcount)
+ ),
+ TP_fast_assign(
+ __entry->dev = mp->m_super->s_dev;
+ __entry->per_intent = per_intent;
+ __entry->step_size = step_size;
+ __entry->logres = logres;
+ __entry->blockcount = blockcount;
+ ),
+ TP_printk("dev %d:%d per_intent %u step_size %u logres %u blockcount %u",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->per_intent,
+ __entry->step_size,
+ __entry->logres,
+ __entry->blockcount)
+);
+
TRACE_EVENT(xlog_intent_recovery_failed,
TP_PROTO(struct xfs_mount *mp, const struct xfs_defer_op_type *ops,
int error),
--
2.31.1
^ permalink raw reply related
* [PATCH v12 16/17] xfs: update atomic write limits
From: John Garry @ 2025-05-06 9:04 UTC (permalink / raw)
To: brauner, djwong, hch, viro, jack, cem
Cc: linux-fsdevel, dchinner, linux-xfs, linux-kernel, ojaswin,
ritesh.list, martin.petersen, linux-ext4, linux-block,
catherine.hoang, linux-api, John Garry
In-Reply-To: <20250506090427.2549456-1-john.g.garry@oracle.com>
Update the limits returned from xfs_get_atomic_write_{min, max, max_opt)().
No reflink support always means no CoW-based atomic writes.
For updating xfs_get_atomic_write_min(), we support blocksize only and that
depends on HW or reflink support.
For updating xfs_get_atomic_write_max(), for no reflink, we are limited to
blocksize but only if HW support. Otherwise we are limited to combined
limit in mp->m_atomic_write_unit_max.
For updating xfs_get_atomic_write_max_opt(), ultimately we are limited by
the bdev atomic write limit. If xfs_get_atomic_write_max() does not report
> 1x blocksize, then just continue to report 0 as before.
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
[djwong: update comments in the helper functions]
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
fs/xfs/xfs_file.c | 2 +-
fs/xfs/xfs_iops.c | 52 +++++++++++++++++++++++++++++++++++++++++------
2 files changed, 47 insertions(+), 7 deletions(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index f4a66ff85748..48254a72071b 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1557,7 +1557,7 @@ xfs_file_open(
if (xfs_is_shutdown(XFS_M(inode->i_sb)))
return -EIO;
file->f_mode |= FMODE_NOWAIT | FMODE_CAN_ODIRECT;
- if (xfs_inode_can_hw_atomic_write(XFS_I(inode)))
+ if (xfs_get_atomic_write_min(XFS_I(inode)) > 0)
file->f_mode |= FMODE_CAN_ATOMIC_WRITE;
return generic_file_open(inode, file);
}
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 77a0606e9dc9..8cddbb7c149b 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -605,27 +605,67 @@ unsigned int
xfs_get_atomic_write_min(
struct xfs_inode *ip)
{
- if (!xfs_inode_can_hw_atomic_write(ip))
- return 0;
+ struct xfs_mount *mp = ip->i_mount;
+
+ /*
+ * If we can complete an atomic write via atomic out of place writes,
+ * then advertise a minimum size of one fsblock. Without this
+ * mechanism, we can only guarantee atomic writes up to a single LBA.
+ *
+ * If out of place writes are not available, we can guarantee an atomic
+ * write of exactly one single fsblock if the bdev will make that
+ * guarantee for us.
+ */
+ if (xfs_inode_can_hw_atomic_write(ip) || xfs_can_sw_atomic_write(mp))
+ return mp->m_sb.sb_blocksize;
- return ip->i_mount->m_sb.sb_blocksize;
+ return 0;
}
unsigned int
xfs_get_atomic_write_max(
struct xfs_inode *ip)
{
- if (!xfs_inode_can_hw_atomic_write(ip))
+ struct xfs_mount *mp = ip->i_mount;
+
+ /*
+ * If out of place writes are not available, we can guarantee an atomic
+ * write of exactly one single fsblock if the bdev will make that
+ * guarantee for us.
+ */
+ if (!xfs_can_sw_atomic_write(mp)) {
+ if (xfs_inode_can_hw_atomic_write(ip))
+ return mp->m_sb.sb_blocksize;
return 0;
+ }
- return ip->i_mount->m_sb.sb_blocksize;
+ /*
+ * If we can complete an atomic write via atomic out of place writes,
+ * then advertise a maximum size of whatever we can complete through
+ * that means. Hardware support is reported via max_opt, not here.
+ */
+ if (XFS_IS_REALTIME_INODE(ip))
+ return XFS_FSB_TO_B(mp, mp->m_groups[XG_TYPE_RTG].awu_max);
+ return XFS_FSB_TO_B(mp, mp->m_groups[XG_TYPE_AG].awu_max);
}
unsigned int
xfs_get_atomic_write_max_opt(
struct xfs_inode *ip)
{
- return 0;
+ unsigned int awu_max = xfs_get_atomic_write_max(ip);
+
+ /* if the max is 1x block, then just keep behaviour that opt is 0 */
+ if (awu_max <= ip->i_mount->m_sb.sb_blocksize)
+ return 0;
+
+ /*
+ * Advertise the maximum size of an atomic write that we can tell the
+ * block device to perform for us. In general the bdev limit will be
+ * less than our out of place write limit, but we don't want to exceed
+ * the awu_max.
+ */
+ return min(awu_max, xfs_inode_buftarg(ip)->bt_bdev_awu_max);
}
static void
--
2.31.1
^ permalink raw reply related
* Re: [PATCH v3 3/3] selftests: pidfd: add tests for PIDFD_SELF_*
From: Lorenzo Stoakes @ 2025-05-06 9:28 UTC (permalink / raw)
To: Christian Brauner
Cc: Peter Zijlstra, John Hubbard, Shuah Khan, Christian Brauner,
Shuah Khan, Liam R . Howlett, Suren Baghdasaryan, Vlastimil Babka,
pedro.falcato, linux-kselftest, linux-mm, linux-fsdevel,
linux-api, linux-kernel, Oliver Sang, seanjc
In-Reply-To: <20250505-postablage-drinnen-ddaa539abc18@brauner>
On Mon, May 05, 2025 at 03:35:13PM +0200, Christian Brauner wrote:
> I'm completely lost as to what's happening here or whether the test here
> is somehow at fault for something.
>
> The pidfd.h head explicitly has no dependency on the pidfd uapi header
> itself and I will NAK anything that makes it so. It's just a giant pain.
There was a debate in my series here about my having to make things work with
'make headers', but thanks to John we resolved it the sane way by using the
tools/ stuff.
I _believe_ Peter is just using this thread as an example of a recent case of
people being asked to do this insanity (correct me if I'm wrong Peter) and it's
unrelated to pidfs in general.
^ permalink raw reply
* Re: [PATCH v12 02/17] xfs: only call xfs_setsize_buftarg once per buffer target
From: Christoph Hellwig @ 2025-05-06 12:00 UTC (permalink / raw)
To: John Garry
Cc: brauner, djwong, hch, viro, jack, cem, linux-fsdevel, dchinner,
linux-xfs, linux-kernel, ojaswin, ritesh.list, martin.petersen,
linux-ext4, linux-block, catherine.hoang, linux-api
In-Reply-To: <20250506090427.2549456-3-john.g.garry@oracle.com>
Looks good:
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply
* [PATCH 3/3] AppArmor: add support for lsm_manage_policy
From: Maxime Bélair @ 2025-05-06 14:32 UTC (permalink / raw)
To: linux-security-module
Cc: john.johansen, paul, jmorris, serge, mic, kees,
stephen.smalley.work, casey, takedakn, penguin-kernel, linux-api,
apparmor, linux-kernel, Maxime Bélair
In-Reply-To: <20250506143254.718647-1-maxime.belair@canonical.com>
Enable users to manage AppArmor policies through the new hook
lsm_manage_policy. Currently, policies can be added but not replaced
using this new mechanism, ensuring that this interface can only further
confine the system.
Signed-off-by: Maxime Bélair <maxime.belair@canonical.com>
---
security/apparmor/apparmorfs.c | 19 +++++++++++++++++++
security/apparmor/include/apparmorfs.h | 3 +++
security/apparmor/lsm.c | 16 ++++++++++++++++
3 files changed, 38 insertions(+)
diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c
index 6039afae4bfc..9abb17e8fdd0 100644
--- a/security/apparmor/apparmorfs.c
+++ b/security/apparmor/apparmorfs.c
@@ -439,6 +439,25 @@ static ssize_t policy_update(u32 mask, const char __user *buf, size_t size,
return error;
}
+/**
+ * aa_profile_load_current_ns - load a profile into the current namespace
+ * @buf buffer containing the user-provided policy
+ * @size size of @buf
+ * @ppos position pointer in the file
+ *
+ * Returns: 0 on success, negative value on error
+ */
+ssize_t aa_profile_load_current_ns(const void __user *buf, size_t size,
+ loff_t *ppos)
+{
+ struct aa_ns *ns = aa_get_current_ns();
+ int error = policy_update(AA_MAY_LOAD_POLICY, buf, size, ppos, ns);
+
+ aa_put_ns(ns);
+
+ return error >= 0 ? 0 : error;
+}
+
/* .load file hook fn to load policy */
static ssize_t profile_load(struct file *f, const char __user *buf, size_t size,
loff_t *pos)
diff --git a/security/apparmor/include/apparmorfs.h b/security/apparmor/include/apparmorfs.h
index 1e94904f68d9..ba2384e3fb93 100644
--- a/security/apparmor/include/apparmorfs.h
+++ b/security/apparmor/include/apparmorfs.h
@@ -112,6 +112,9 @@ int __aafs_profile_mkdir(struct aa_profile *profile, struct dentry *parent);
void __aafs_ns_rmdir(struct aa_ns *ns);
int __aafs_ns_mkdir(struct aa_ns *ns, struct dentry *parent, const char *name,
struct dentry *dent);
+ssize_t aa_profile_load_current_ns(const void __user *buf, size_t size,
+ loff_t *ppos);
+
struct aa_loaddata;
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 9b6c2f157f83..21f3c4db0e4e 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -1275,6 +1275,20 @@ static int apparmor_socket_shutdown(struct socket *sock, int how)
return aa_sock_perm(OP_SHUTDOWN, AA_MAY_SHUTDOWN, sock);
}
+static int apparmor_lsm_manage_policy(u32 lsm_id, u32 op, void __user *buf,
+ size_t size, u32 flags)
+{
+ loff_t pos = 0; // Partial writing is not currently supported
+
+ if (lsm_id != LSM_ID_APPARMOR)
+ return 0;
+
+ if (op != LSM_POLICY_LOAD || flags)
+ return -EOPNOTSUPP;
+
+ return aa_profile_load_current_ns(buf, size, &pos);
+}
+
#ifdef CONFIG_NETWORK_SECMARK
/**
* apparmor_socket_sock_rcv_skb - check perms before associating skb to sk
@@ -1483,6 +1497,8 @@ static struct security_hook_list apparmor_hooks[] __ro_after_init = {
LSM_HOOK_INIT(socket_getsockopt, apparmor_socket_getsockopt),
LSM_HOOK_INIT(socket_setsockopt, apparmor_socket_setsockopt),
LSM_HOOK_INIT(socket_shutdown, apparmor_socket_shutdown),
+
+ LSM_HOOK_INIT(lsm_manage_policy, apparmor_lsm_manage_policy),
#ifdef CONFIG_NETWORK_SECMARK
LSM_HOOK_INIT(socket_sock_rcv_skb, apparmor_socket_sock_rcv_skb),
#endif
--
2.48.1
^ permalink raw reply related
* [PATCH 1/3] Wire up the lsm_manage_policy syscall
From: Maxime Bélair @ 2025-05-06 14:32 UTC (permalink / raw)
To: linux-security-module
Cc: john.johansen, paul, jmorris, serge, mic, kees,
stephen.smalley.work, casey, takedakn, penguin-kernel, linux-api,
apparmor, linux-kernel, Maxime Bélair
In-Reply-To: <20250506143254.718647-1-maxime.belair@canonical.com>
Add support for the new lsm_manage_policy syscall, providing a unified
API for loading and modifying LSM policies without requiring the LSM’s
pseudo-filesystem.
Benefits:
- Works even if the LSM pseudo-filesystem isn’t mounted or available
(e.g. in containers)
- Offers a logical and unified interface rather than multiple
heterogeneous pseudo-filesystems.
- Avoids overhead of other kernel interfaces for better efficiency
Signed-off-by: Maxime Bélair <maxime.belair@canonical.com>
---
arch/alpha/kernel/syscalls/syscall.tbl | 1 +
arch/arm/tools/syscall.tbl | 1 +
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
include/linux/syscalls.h | 4 ++++
include/uapi/asm-generic/unistd.h | 4 +++-
kernel/sys_ni.c | 1 +
security/lsm_syscalls.c | 6 ++++++
tools/include/uapi/asm-generic/unistd.h | 4 +++-
tools/perf/arch/x86/entry/syscalls/syscall_64.tbl | 1 +
10 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 2dd6340de6b4..dfe6cd43c584 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -507,3 +507,4 @@
575 common listxattrat sys_listxattrat
576 common removexattrat sys_removexattrat
577 common open_tree_attr sys_open_tree_attr
+578 common lsm_manage_policy sys_lsm_manage_policy
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index 27c1d5ebcd91..60abcb3a8a1b 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -482,3 +482,4 @@
465 common listxattrat sys_listxattrat
466 common removexattrat sys_removexattrat
467 common open_tree_attr sys_open_tree_attr
+468 common lsm_manage_policy sys_lsm_manage_policy
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index ac007ea00979..bb91a929757a 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -473,3 +473,4 @@
465 i386 listxattrat sys_listxattrat
466 i386 removexattrat sys_removexattrat
467 i386 open_tree_attr sys_open_tree_attr
+468 i386 lsm_manage_policy sys_lsm_manage_policy
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index cfb5ca41e30d..83819d4a5c8a 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -391,6 +391,7 @@
465 common listxattrat sys_listxattrat
466 common removexattrat sys_removexattrat
467 common open_tree_attr sys_open_tree_attr
+468 common lsm_manage_policy sys_lsm_manage_policy
#
# Due to a historical design error, certain syscalls are numbered differently
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e5603cc91963..f52a0678b1d0 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -989,6 +989,10 @@ asmlinkage long sys_lsm_set_self_attr(unsigned int attr, struct lsm_ctx __user *
u32 size, u32 flags);
asmlinkage long sys_lsm_list_modules(u64 __user *ids, u32 __user *size, u32 flags);
+asmlinkage long sys_lsm_manage_policy(u32 lsm_id, u32 op, void __user *buf,
+ u32 __user *size, u32 flags);
+
+
/*
* Architecture-specific system calls
*/
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 2892a45023af..b94369baded8 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -851,9 +851,11 @@ __SYSCALL(__NR_listxattrat, sys_listxattrat)
__SYSCALL(__NR_removexattrat, sys_removexattrat)
#define __NR_open_tree_attr 467
__SYSCALL(__NR_open_tree_attr, sys_open_tree_attr)
+#define __NR_lsm_manage_policy 468
+__SYSCALL(__NR_lsm_manage_policy, lsm_manage_policy)
#undef __NR_syscalls
-#define __NR_syscalls 468
+#define __NR_syscalls 469
/*
* 32 bit systems traditionally used different
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index c00a86931f8c..e556b07d8716 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -172,6 +172,7 @@ COND_SYSCALL_COMPAT(fadvise64_64);
COND_SYSCALL(lsm_get_self_attr);
COND_SYSCALL(lsm_set_self_attr);
COND_SYSCALL(lsm_list_modules);
+COND_SYSCALL(lsm_manage_policy);
/* CONFIG_MMU only */
COND_SYSCALL(swapon);
diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c
index 8440948a690c..dcaad8818679 100644
--- a/security/lsm_syscalls.c
+++ b/security/lsm_syscalls.c
@@ -118,3 +118,9 @@ SYSCALL_DEFINE3(lsm_list_modules, u64 __user *, ids, u32 __user *, size,
return lsm_active_cnt;
}
+
+SYSCALL_DEFINE5(lsm_manage_policy, u32, lsm_id, u32, op, void __user *, buf, u32
+ __user *, size, u32, flags)
+{
+ return 0;
+}
diff --git a/tools/include/uapi/asm-generic/unistd.h b/tools/include/uapi/asm-generic/unistd.h
index 2892a45023af..b94369baded8 100644
--- a/tools/include/uapi/asm-generic/unistd.h
+++ b/tools/include/uapi/asm-generic/unistd.h
@@ -851,9 +851,11 @@ __SYSCALL(__NR_listxattrat, sys_listxattrat)
__SYSCALL(__NR_removexattrat, sys_removexattrat)
#define __NR_open_tree_attr 467
__SYSCALL(__NR_open_tree_attr, sys_open_tree_attr)
+#define __NR_lsm_manage_policy 468
+__SYSCALL(__NR_lsm_manage_policy, lsm_manage_policy)
#undef __NR_syscalls
-#define __NR_syscalls 468
+#define __NR_syscalls 469
/*
* 32 bit systems traditionally used different
diff --git a/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl b/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
index cfb5ca41e30d..83819d4a5c8a 100644
--- a/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
@@ -391,6 +391,7 @@
465 common listxattrat sys_listxattrat
466 common removexattrat sys_removexattrat
467 common open_tree_attr sys_open_tree_attr
+468 common lsm_manage_policy sys_lsm_manage_policy
#
# Due to a historical design error, certain syscalls are numbered differently
--
2.48.1
^ permalink raw reply related
* [PATCH 2/3] lsm: introduce security_lsm_manage_policy hook
From: Maxime Bélair @ 2025-05-06 14:32 UTC (permalink / raw)
To: linux-security-module
Cc: john.johansen, paul, jmorris, serge, mic, kees,
stephen.smalley.work, casey, takedakn, penguin-kernel, linux-api,
apparmor, linux-kernel, Maxime Bélair
In-Reply-To: <20250506143254.718647-1-maxime.belair@canonical.com>
Define a new LSM hook security_lsm_manage_policy and wire it into the
lsm_manage_policy() syscall so that LSMs can register a unified interface
for policy management. This initial, minimal implementation only supports
the LSM_POLICY_LOAD operation to limit changes.
Signed-off-by: Maxime Bélair <maxime.belair@canonical.com>
---
include/linux/lsm_hook_defs.h | 2 ++
include/linux/security.h | 7 +++++++
include/uapi/linux/lsm.h | 8 ++++++++
security/lsm_syscalls.c | 7 ++++++-
security/security.c | 21 +++++++++++++++++++++
5 files changed, 44 insertions(+), 1 deletion(-)
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index bf3bbac4e02a..04b6e34d5111 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -464,3 +464,5 @@ LSM_HOOK(int, 0, bdev_alloc_security, struct block_device *bdev)
LSM_HOOK(void, LSM_RET_VOID, bdev_free_security, struct block_device *bdev)
LSM_HOOK(int, 0, bdev_setintegrity, struct block_device *bdev,
enum lsm_integrity_type type, const void *value, size_t size)
+LSM_HOOK(int, 0, lsm_manage_policy, u32 lsm_id, u32 op, void __user *buf,
+ size_t size, u32 flags)
diff --git a/include/linux/security.h b/include/linux/security.h
index cc9b54d95d22..dab547ee691c 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -581,6 +581,8 @@ void security_bdev_free(struct block_device *bdev);
int security_bdev_setintegrity(struct block_device *bdev,
enum lsm_integrity_type type, const void *value,
size_t size);
+int security_lsm_manage_policy(u32 lsm_id, u32 op, void __user *buf,
+ size_t size, u32 flags);
#else /* CONFIG_SECURITY */
/**
@@ -1602,6 +1604,11 @@ static inline int security_bdev_setintegrity(struct block_device *bdev,
{
return 0;
}
+static int security_lsm_manage_policy(u32 lsm_id, u32 op, void __user *buf,
+ size_t size, u32 flags)
+
+ return -EOPNOTSUPP;
+}
#endif /* CONFIG_SECURITY */
diff --git a/include/uapi/linux/lsm.h b/include/uapi/linux/lsm.h
index 938593dfd5da..7335f9723114 100644
--- a/include/uapi/linux/lsm.h
+++ b/include/uapi/linux/lsm.h
@@ -90,4 +90,12 @@ struct lsm_ctx {
*/
#define LSM_FLAG_SINGLE 0x0001
+/*
+ * LSM_POLICY_XXX definition identifies operation to manage lsm
+ * policies
+ */
+
+#define LSM_POLICY_UNDEF 0
+#define LSM_POLICY_LOAD 100
+
#endif /* _UAPI_LINUX_LSM_H */
diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c
index dcaad8818679..b39e6635a7d5 100644
--- a/security/lsm_syscalls.c
+++ b/security/lsm_syscalls.c
@@ -122,5 +122,10 @@ SYSCALL_DEFINE3(lsm_list_modules, u64 __user *, ids, u32 __user *, size,
SYSCALL_DEFINE5(lsm_manage_policy, u32, lsm_id, u32, op, void __user *, buf, u32
__user *, size, u32, flags)
{
- return 0;
+ size_t usize;
+
+ if (get_user(usize, size))
+ return -EFAULT;
+
+ return security_lsm_manage_policy(lsm_id, op, buf, usize, flags);
}
diff --git a/security/security.c b/security/security.c
index fb57e8fddd91..256104e338b1 100644
--- a/security/security.c
+++ b/security/security.c
@@ -5883,6 +5883,27 @@ int security_bdev_setintegrity(struct block_device *bdev,
}
EXPORT_SYMBOL(security_bdev_setintegrity);
+/**
+ * security_lsm_manage_policy() - Manage the policies of LSMs
+ * @lsm_id: id of the lsm to target
+ * @op: Operation to perform (one of the LSM_POLICY_XXX values)
+ * @buf: userspace pointer to policy data
+ * @size: size of @buf
+ * @flags: lsm policy management flags
+ *
+ * Manage the policies of a LSM. This notably allows to update them even when
+ * the lsmfs is unavailable is restricted. Currently, only LSM_POLICY_LOAD is
+ * supported.
+ *
+ * Return: Returns 0 on success, error on failure.
+ */
+int security_lsm_manage_policy(u32 lsm_id, u32 op, void __user *buf,
+ size_t size, u32 flags)
+{
+ return call_int_hook(lsm_manage_policy, lsm_id, op, buf, size, flags);
+}
+EXPORT_SYMBOL(security_lsm_manage_policy);
+
#ifdef CONFIG_PERF_EVENTS
/**
* security_perf_event_open() - Check if a perf event open is allowed
--
2.48.1
^ permalink raw reply related
* [PATCH 0/3] lsm: introduce lsm_manage_policy() syscall
From: Maxime Bélair @ 2025-05-06 14:32 UTC (permalink / raw)
To: linux-security-module
Cc: john.johansen, paul, jmorris, serge, mic, kees,
stephen.smalley.work, casey, takedakn, penguin-kernel, linux-api,
apparmor, linux-kernel, Maxime Bélair
This patchset introduces a new syscall, lsm_manage_policy(), and the
associated Linux Security Module hook security_lsm_manage_policy(),
providing a unified interface for loading and managing LSM policies.
This syscall complements the existing per‑LSM pseudo‑filesystem mechanism
and works even when those filesystems are not mounted or available.
With this new syscall, administrators may lock down access to the
pseudo‑filesystem yet still manage LSM policies. A single, tightly scoped
entry point then replaces the many file operations exposed by those
filesystems, significantly reducing the attack surface. This is
particularly useful in containers or processes already confined by
Landlock, where these pseudo‑filesystems are typically unavailable.
Because it provides a logical and unified interface, lsm_manage_policy()
is simpler to use than several heterogeneous pseudo‑filesystems and
avoids edge cases such as partially loaded policies. It also eliminates
VFS overhead, yielding performance gains notably when many policies are
loaded, for instance at boot time.
This initial implementation is intentionally minimal to limit the scope
of changes. Currently, only policy loading is supported, and only
AppArmor registers this LSM hook. However, any LSM can adopt this
interface, and future patches could extend this syscall to support more
operations, such as replacing, removing, or querying loaded policies.
Landlock already provides three Landlock‑specific syscalls (e.g.
landlock_add_rule()) to restrict ambient rights for sets of processes
without touching any pseudo-filesystem. lsm_manage_policy() generalizes
that approach to the entire LSM layer, so any module can expose its
policy operations through one uniform interface and reap the advantages
outlined above.
This patchset is available at [1] and a minimal user space example
showing how to use this syscall with AppArmor is at [2].
[1] https://github.com/emixam16/linux/tree/lsm_syscall
[2] https://gitlab.com/emixam16/apparmor/tree/lsm_syscall
Maxime Bélair (3):
Wire up the lsm_manage_policy syscall
lsm: introduce security_lsm_manage_policy hook
AppArmor: add support for lsm_manage_policy
arch/alpha/kernel/syscalls/syscall.tbl | 1 +
arch/arm/tools/syscall.tbl | 1 +
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
include/linux/lsm_hook_defs.h | 2 ++
include/linux/security.h | 7 +++++++
include/linux/syscalls.h | 4 ++++
include/uapi/asm-generic/unistd.h | 4 +++-
include/uapi/linux/lsm.h | 8 +++++++
kernel/sys_ni.c | 1 +
security/apparmor/apparmorfs.c | 19 +++++++++++++++++
security/apparmor/include/apparmorfs.h | 3 +++
security/apparmor/lsm.c | 16 ++++++++++++++
security/lsm_syscalls.c | 11 ++++++++++
security/security.c | 21 +++++++++++++++++++
tools/include/uapi/asm-generic/unistd.h | 4 +++-
.../arch/x86/entry/syscalls/syscall_64.tbl | 1 +
17 files changed, 103 insertions(+), 2 deletions(-)
base-commit: 9c32cda43eb78f78c73aee4aa344b777714e259b
--
2.48.1
^ permalink raw reply
* Re: [PATCH v3 3/3] selftests: pidfd: add tests for PIDFD_SELF_*
From: Shuah Khan @ 2025-05-06 21:18 UTC (permalink / raw)
To: Peter Zijlstra, John Hubbard
Cc: Lorenzo Stoakes, Christian Brauner, Shuah Khan, Liam R . Howlett,
Suren Baghdasaryan, Vlastimil Babka, pedro.falcato,
linux-kselftest, linux-mm, linux-fsdevel, linux-api, linux-kernel,
Oliver Sang, seanjc, Shuah Khan
In-Reply-To: <20250501114235.GP4198@noisy.programming.kicks-ass.net>
On 5/1/25 05:42, Peter Zijlstra wrote:
> On Wed, Oct 16, 2024 at 07:14:34PM -0700, John Hubbard wrote:
>> On 10/16/24 3:06 PM, Lorenzo Stoakes wrote:
>>> On Wed, Oct 16, 2024 at 02:00:27PM -0600, Shuah Khan wrote:
>>>> On 10/16/24 04:20, Lorenzo Stoakes wrote:
>> ...
>>>>> diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h
>>>>> index 88d6830ee004..1640b711889b 100644
>>>>> --- a/tools/testing/selftests/pidfd/pidfd.h
>>>>> +++ b/tools/testing/selftests/pidfd/pidfd.h
>>>>> @@ -50,6 +50,14 @@
>>>>> #define PIDFD_NONBLOCK O_NONBLOCK
>>>>> #endif
>>>>> +/* System header file may not have this available. */
>>>>> +#ifndef PIDFD_SELF_THREAD
>>>>> +#define PIDFD_SELF_THREAD -100
>>>>> +#endif
>>>>> +#ifndef PIDFD_SELF_THREAD_GROUP
>>>>> +#define PIDFD_SELF_THREAD_GROUP -200
>>>>> +#endif
>>>>> +
>>>>
>>>> As mentioned in my response to v1 patch:
>>>>
>>>> kselftest has dependency on "make headers" and tests include
>>>> headers from linux/ directory
>>>
>>> Right but that assumes you install the kernel headers on the build system,
>>> which is quite a painful thing to have to do when you are quickly iterating
>>> on a qemu setup.
>>>
>>> This is a use case I use all the time so not at all theoretical.
>>>
>>
>> This is turning out to be a fairly typical reaction from kernel
>> developers, when presented with the "you must first run make headers"
>> requirement for kselftests.
>>
>> Peter Zijlstra's "NAK NAK NAK" response [1] last year was the most
>> colorful, so I'll helpfully cite it here. :)
>
> Let me re-try this.
>
> This is driving me insane. I've spend the past _TWO_ days trying to
> build KVM selftests and I'm still failing.
>
> This is absolute atrocious crap and is costing me valuable time.
>
> Please fix this fucking selftests shit to just build. This is unusable
> garbage.
I don't recall all the reasons why kselftests needed "make headers"
One reason I could think of was that when a new test depends on a
header change, the test won't build unless headers are installed.
If this requirement is causing problems for tests that don't fall
into the category and we probably have more of them mow, we can
clean that up.
John, you mentioned you got mm tests working without headers?
Can you share the commit here.
thanks,
-- Shuah
^ permalink raw reply
* Re: [PATCH v3 3/3] selftests: pidfd: add tests for PIDFD_SELF_*
From: John Hubbard @ 2025-05-06 21:34 UTC (permalink / raw)
To: Shuah Khan, Peter Zijlstra
Cc: Lorenzo Stoakes, Christian Brauner, Shuah Khan, Liam R . Howlett,
Suren Baghdasaryan, Vlastimil Babka, pedro.falcato,
linux-kselftest, linux-mm, linux-fsdevel, linux-api, linux-kernel,
Oliver Sang, seanjc
In-Reply-To: <17464a97-e7be-49d4-9422-96ff824dba7c@linuxfoundation.org>
On 5/6/25 2:18 PM, Shuah Khan wrote:
> On 5/1/25 05:42, Peter Zijlstra wrote:
>> On Wed, Oct 16, 2024 at 07:14:34PM -0700, John Hubbard wrote:
>>> On 10/16/24 3:06 PM, Lorenzo Stoakes wrote:
>>>> On Wed, Oct 16, 2024 at 02:00:27PM -0600, Shuah Khan wrote:
>>>>> On 10/16/24 04:20, Lorenzo Stoakes wrote:
>>> ...
>> Please fix this fucking selftests shit to just build. This is unusable
>> garbage.
>
> I don't recall all the reasons why kselftests needed "make headers"
> One reason I could think of was that when a new test depends on a
> header change, the test won't build unless headers are installed.
...or until an updated copy of that updated header file is copied
somewhere, and then included in the kselftests. That's the approach
that I ultimately settled upon, after some discussion and negotion.
Details below.
>
> If this requirement is causing problems for tests that don't fall
> into the category and we probably have more of them mow, we can
> clean that up.
>
> John, you mentioned you got mm tests working without headers?
> Can you share the commit here.
>
Yes. This one sets up the general approach, which is available to
all kselftests: TOOLS_INCLUDES. It also changes selftests/mm to
set TOOLS_INCLUDES in that build:
e076eaca5906 ("selftests: break the dependency upon local header files")
And here is a representative application of the above, to selftests/mm. In
other words, taking advantage of the new file location pointed to by
TOOLS_INCLUDES:
580ea358af0a ("selftests/mm: fix additional build errors for selftests")
thanks,
--
John Hubbard
^ permalink raw reply
* Re: [PATCH 2/3] lsm: introduce security_lsm_manage_policy hook
From: Song Liu @ 2025-05-07 6:19 UTC (permalink / raw)
To: Maxime Bélair
Cc: linux-security-module, john.johansen, paul, jmorris, serge, mic,
kees, stephen.smalley.work, casey, takedakn, penguin-kernel,
linux-api, apparmor, linux-kernel
In-Reply-To: <20250506143254.718647-3-maxime.belair@canonical.com>
On Tue, May 6, 2025 at 7:40 AM Maxime Bélair
<maxime.belair@canonical.com> wrote:
>
> Define a new LSM hook security_lsm_manage_policy and wire it into the
> lsm_manage_policy() syscall so that LSMs can register a unified interface
> for policy management. This initial, minimal implementation only supports
> the LSM_POLICY_LOAD operation to limit changes.
>
> Signed-off-by: Maxime Bélair <maxime.belair@canonical.com>
[...]
> diff --git a/security/security.c b/security/security.c
> index fb57e8fddd91..256104e338b1 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -5883,6 +5883,27 @@ int security_bdev_setintegrity(struct block_device *bdev,
> }
> EXPORT_SYMBOL(security_bdev_setintegrity);
>
> +/**
> + * security_lsm_manage_policy() - Manage the policies of LSMs
> + * @lsm_id: id of the lsm to target
> + * @op: Operation to perform (one of the LSM_POLICY_XXX values)
> + * @buf: userspace pointer to policy data
> + * @size: size of @buf
> + * @flags: lsm policy management flags
> + *
> + * Manage the policies of a LSM. This notably allows to update them even when
> + * the lsmfs is unavailable is restricted. Currently, only LSM_POLICY_LOAD is
> + * supported.
> + *
> + * Return: Returns 0 on success, error on failure.
> + */
> +int security_lsm_manage_policy(u32 lsm_id, u32 op, void __user *buf,
> + size_t size, u32 flags)
> +{
> + return call_int_hook(lsm_manage_policy, lsm_id, op, buf, size, flags);
If the LSM doesn't implement this hook, sys_lsm_manage_policy will return 0
for any inputs, right? This is gonna be so confusing for users.
Thanks,
Song
^ permalink raw reply
* Re: [PATCH 1/3] Wire up the lsm_manage_policy syscall
From: Song Liu @ 2025-05-07 6:26 UTC (permalink / raw)
To: Maxime Bélair
Cc: linux-security-module, john.johansen, paul, jmorris, serge, mic,
kees, stephen.smalley.work, casey, takedakn, penguin-kernel,
linux-api, apparmor, linux-kernel
In-Reply-To: <20250506143254.718647-2-maxime.belair@canonical.com>
On Tue, May 6, 2025 at 7:40 AM Maxime Bélair
<maxime.belair@canonical.com> wrote:
>
> Add support for the new lsm_manage_policy syscall, providing a unified
> API for loading and modifying LSM policies without requiring the LSM’s
> pseudo-filesystem.
>
> Benefits:
> - Works even if the LSM pseudo-filesystem isn’t mounted or available
> (e.g. in containers)
> - Offers a logical and unified interface rather than multiple
> heterogeneous pseudo-filesystems.
These two do not feel like real benefits:
- Not working in containers is often not an issue, but a feature.
- One syscall cannot fit all use cases well...
> - Avoids overhead of other kernel interfaces for better efficiency
.. and it is is probably less efficient, because everything need to
fit in the same API.
Overall, this set doesn't feel like a good change to me.
Thanks,
Song
^ permalink raw reply
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