Re: [PATCH v2] ext4: set csum seed in tmp inode while migrating to extents

Luís Henriques
2021-12-15T16:01:18Z

On Wed, Dec 15, 2021 at 03:12:37PM +0100, Lukas Czerner wrote:
> On Wed, Dec 15, 2021 at 12:28:52PM +0100, Jan Kara wrote:
> > On Tue 14-12-21 16:49:45, Darrick J. Wong wrote:
> > > On Tue, Dec 14, 2021 at 05:50:58PM +0000, Luís Henriques wrote:
> > > > When migrating to extents, the temporary inode will have it's own checksum
> > > > seed. This means that, when swapping the inodes data, the inode checksums
> > > > will be incorrect.
> > > >
> > > > This can be fixed by recalculating the extents checksums again. Or simply
> > > > by copying the seed into the temporary inode.
> > > >
> > > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=213357
> > > > Reported-by: Jeroen van Wolffelaar <jeroen@wolffelaar.nl>
> > > > Signed-off-by: Luís Henriques <lhenriques@suse.de>
> > > > ---
> > > > fs/ext4/migrate.c | 12 +++++++++++-
> > > > 1 file changed, 11 insertions(+), 1 deletion(-)
> > > >
> > > > changes since v1:
> > > >
> > > > * Dropped tmp_ei variable
> > > > * ->i_csum_seed is now initialised immediately after tmp_inode is created
> > > > * New comment about the seed initialization and stating that recovery
> > > > needs to be fixed.
> > > >
> > > > Cheers,
> > > > --
> > > > Luís
> > > >
> > > > diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
> > > > index 7e0b4f81c6c0..36dfc88ce05b 100644
> > > > --- a/fs/ext4/migrate.c
> > > > +++ b/fs/ext4/migrate.c
> > > > @@ -459,6 +459,17 @@ int ext4_ext_migrate(struct inode *inode)
> > > > ext4_journal_stop(handle);
> > > > goto out_unlock;
> > > > }
> > > > + /*
> > > > + * Use the correct seed for checksum (i.e. the seed from 'inode'). This
> > > > + * is so that the metadata blocks will have the correct checksum after
> > > > + * the migration.
> > > > + *
> > > > + * Note however that, if a crash occurs during the migration process,
> > > > + * the recovery process is broken because the tmp_inode checksums will
> > > > + * be wrong and the orphans cleanup will fail.
> > >
> > > ...and then what does the user do?
> >
> > Run fsck of course! And then recover from backups :) I know this is sad but
> > the situation is that our migration code just is not crash-safe (if we
> > crash we are going to free blocks that are still used by the migrated
> > inode) and Luis makes it work in case we do not crash (which should be
> > hopefully more common) and documents it does not work in case we crash.
> > So overall I'd call it a win.
> >
> > But maybe we should just remove this online-migration functionality
> > completely from the kernel? That would be also a fine solution for me. I
> > was thinking whether we could somehow make the inode migration crash-safe
> > but I didn't think of anything which would not require on-disk format
> > change...
>
> Since this is not something that anyone can honestly recommend doing
> without a prior backup and a word of warning I personaly would be in favor
> of removing it.

It's odd that my first fix to ext4 ends up wiping out a whole feature :-)

Anyway, in case the decision is to go ahead with the feature removal, I'm
inlining bellow an RFC that simply removes the whole file (and returns
-EOPNOTSUPP in the appropriate places). This was only compile-tested, so
I may have missed something.

(Oh, I almost forgot: I also wanted to mention the word dromedary just to
mess a little bit with Jon's article in tomorrow's LWN :-) )

Cheers,
--
Luís

From 19810c891ca612fafbfdeeea6651ba5484d5039f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lu=C3=ADs=20Henriques?= <lhenriques@suse.de>
Date: Wed, 15 Dec 2021 15:10:26 +0000
Subject: [RFC PATCH] ext4: remove online-migration feature from the kernel
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Online migration is currently broken (see link bellow). Although this
specific issue could be easily fixed, it seems to be very difficult to
implement it in a safe manner so that recovery can be done without risking
loosing data. Instead of changing on-disk format, simply wipe the whole
feature.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=213357
Reported-by: Jeroen van Wolffelaar <jeroen@wolffelaar.nl>
Signed-off-by: Luís Henriques <lhenriques@suse.de>
---
fs/ext4/Makefile | 2 +-
fs/ext4/ext4.h | 4 -
fs/ext4/ioctl.c | 33 +--
fs/ext4/migrate.c | 669 ----------------------------------------------
4 files changed, 7 insertions(+), 701 deletions(-)
delete mode 100644 fs/ext4/migrate.c

diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile
index 7d89142e1421..d904a1cbc3d8 100644
--- a/fs/ext4/Makefile
+++ b/fs/ext4/Makefile
@@ -7,7 +7,7 @@ obj-$(CONFIG_EXT4_FS) += ext4.o

ext4-y := balloc.o bitmap.o block_validity.o dir.o ext4_jbd2.o extents.o \
extents_status.o file.o fsmap.o fsync.o hash.o ialloc.o \
- indirect.o inline.o inode.o ioctl.o mballoc.o migrate.o \
+ indirect.o inline.o inode.o ioctl.o mballoc.o \
mmp.o move_extent.o namei.o page-io.o readpage.o resize.o \
super.o symlink.o sysfs.o xattr.o xattr_hurd.o xattr_trusted.o \
xattr_user.o fast_commit.o orphan.o
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 404dd50856e5..7b92120cb560 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3062,10 +3062,6 @@ int ext4_fileattr_set(struct user_namespace *mnt_userns,
int ext4_fileattr_get(struct dentry *dentry, struct fileattr *fa);
extern void ext4_reset_inode_seed(struct inode *inode);

-/* migrate.c */
-extern int ext4_ext_migrate(struct inode *);
-extern int ext4_ind_migrate(struct inode *inode);
-
/* namei.c */
extern int ext4_init_new_dir(handle_t *handle, struct inode *dir,
struct inode *inode);
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 606dee9e08a3..07f8461f69da 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -341,7 +341,7 @@ static int ext4_ioctl_setflags(struct inode *inode,
{
struct ext4_inode_info *ei = EXT4_I(inode);
handle_t *handle = NULL;
- int err = -EPERM, migrate = 0;
+ int err = -EPERM;
struct ext4_iloc iloc;
unsigned int oldflags, mask, i;
struct super_block *sb = inode->i_sb;
@@ -365,8 +365,10 @@ static int ext4_ioctl_setflags(struct inode *inode,
goto flags_out;
}

- if ((flags ^ oldflags) & EXT4_EXTENTS_FL)
- migrate = 1;
+ if ((flags ^ oldflags) & EXT4_EXTENTS_FL) {
+ err = -EOPNOTSUPP;
+ goto flags_out;
+ }

if ((flags ^ oldflags) & EXT4_CASEFOLD_FL) {
if (!ext4_has_feature_casefold(sb)) {
@@ -449,12 +451,6 @@ static int ext4_ioctl_setflags(struct inode *inode,
if (err)
goto flags_out;
}
- if (migrate) {
- if (flags & EXT4_EXTENTS_FL)
- err = ext4_ext_migrate(inode);
- else
- err = ext4_ind_migrate(inode);
- }

flags_out:
return err;
@@ -1009,24 +1005,7 @@ static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)

case EXT4_IOC_MIGRATE:
{
- int err;
- if (!inode_owner_or_capable(mnt_userns, inode))
- return -EACCES;
-
- err = mnt_want_write_file(filp);
- if (err)
- return err;
- /*
- * inode_mutex prevent write and truncate on the file.
- * Read still goes through. We take i_data_sem in
- * ext4_ext_swap_inode_data before we switch the
- * inode format to prevent read.
- */
- inode_lock((inode));
- err = ext4_ext_migrate(inode);
- inode_unlock((inode));
- mnt_drop_write_file(filp);
- return err;
+ return -EOPNOTSUPP;
}

case EXT4_IOC_ALLOC_DA_BLKS:
diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
deleted file mode 100644
index 7e0b4f81c6c0..000000000000
--- a/fs/ext4/migrate.c
+++ /dev/null
@@ -1,669 +0,0 @@
-// SPDX-License-Identifier: LGPL-2.1
-/*
- * Copyright IBM Corporation, 2007
- * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
- *
- */
-
-#include <linux/slab.h>
-#include "ext4_jbd2.h"
-#include "ext4_extents.h"
-
-/*
- * The contiguous blocks details which can be
- * represented by a single extent
- */
-struct migrate_struct {
- ext4_lblk_t first_block, last_block, curr_block;
- ext4_fsblk_t first_pblock, last_pblock;
-};
-
-static int finish_range(handle_t *handle, struct inode *inode,
- struct migrate_struct *lb)
-
-{
- int retval = 0, needed;
- struct ext4_extent newext;
- struct ext4_ext_path *path;
- if (lb->first_pblock == 0)
- return 0;
-
- /* Add the extent to temp inode*/
- newext.ee_block = cpu_to_le32(lb->first_block);
- newext.ee_len = cpu_to_le16(lb->last_block - lb->first_block + 1);
- ext4_ext_store_pblock(&newext, lb->first_pblock);
- /* Locking only for convenience since we are operating on temp inode */
- down_write(&EXT4_I(inode)->i_data_sem);
- path = ext4_find_extent(inode, lb->first_block, NULL, 0);
- if (IS_ERR(path)) {
- retval = PTR_ERR(path);
- path = NULL;
- goto err_out;
- }
-
- /*
- * Calculate the credit needed to inserting this extent
- * Since we are doing this in loop we may accumulate extra
- * credit. But below we try to not accumulate too much
- * of them by restarting the journal.
- */
- needed = ext4_ext_calc_credits_for_single_extent(inode,
- lb->last_block - lb->first_block + 1, path);
-
- retval = ext4_datasem_ensure_credits(handle, inode, needed, needed, 0);
- if (retval < 0)
- goto err_out;
- retval = ext4_ext_insert_extent(handle, inode, &path, &newext, 0);
-err_out:
- up_write((&EXT4_I(inode)->i_data_sem));
- ext4_ext_drop_refs(path);
- kfree(path);
- lb->first_pblock = 0;
- return retval;
-}
-
-static int update_extent_range(handle_t *handle, struct inode *inode,
- ext4_fsblk_t pblock, struct migrate_struct *lb)
-{
- int retval;
- /*
- * See if we can add on to the existing range (if it exists)
- */
- if (lb->first_pblock &&
- (lb->last_pblock+1 == pblock) &&
- (lb->last_block+1 == lb->curr_block)) {
- lb->last_pblock = pblock;
- lb->last_block = lb->curr_block;
- lb->curr_block++;
- return 0;
- }
- /*
- * Start a new range.
- */
- retval = finish_range(handle, inode, lb);
- lb->first_pblock = lb->last_pblock = pblock;
- lb->first_block = lb->last_block = lb->curr_block;
- lb->curr_block++;
- return retval;
-}
-
-static int update_ind_extent_range(handle_t *handle, struct inode *inode,
- ext4_fsblk_t pblock,
- struct migrate_struct *lb)
-{
- struct buffer_head *bh;
- __le32 *i_data;
- int i, retval = 0;
- unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
-
- bh = ext4_sb_bread(inode->i_sb, pblock, 0);
- if (IS_ERR(bh))
- return PTR_ERR(bh);
-
- i_data = (__le32 *)bh->b_data;
- for (i = 0; i < max_entries; i++) {
- if (i_data[i]) {
- retval = update_extent_range(handle, inode,
- le32_to_cpu(i_data[i]), lb);
- if (retval)
- break;
- } else {
- lb->curr_block++;
- }
- }
- put_bh(bh);
- return retval;
-
-}
-
-static int update_dind_extent_range(handle_t *handle, struct inode *inode,
- ext4_fsblk_t pblock,
- struct migrate_struct *lb)
-{
- struct buffer_head *bh;
- __le32 *i_data;
- int i, retval = 0;
- unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
-
- bh = ext4_sb_bread(inode->i_sb, pblock, 0);
- if (IS_ERR(bh))
- return PTR_ERR(bh);
-
- i_data = (__le32 *)bh->b_data;
- for (i = 0; i < max_entries; i++) {
- if (i_data[i]) {
- retval = update_ind_extent_range(handle, inode,
- le32_to_cpu(i_data[i]), lb);
- if (retval)
- break;
- } else {
- /* Only update the file block number */
- lb->curr_block += max_entries;
- }
- }
- put_bh(bh);
- return retval;
-
-}
-
-static int update_tind_extent_range(handle_t *handle, struct inode *inode,
- ext4_fsblk_t pblock,
- struct migrate_struct *lb)
-{
- struct buffer_head *bh;
- __le32 *i_data;
- int i, retval = 0;
- unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
-
- bh = ext4_sb_bread(inode->i_sb, pblock, 0);
- if (IS_ERR(bh))
- return PTR_ERR(bh);
-
- i_data = (__le32 *)bh->b_data;
- for (i = 0; i < max_entries; i++) {
- if (i_data[i]) {
- retval = update_dind_extent_range(handle, inode,
- le32_to_cpu(i_data[i]), lb);
- if (retval)
- break;
- } else {
- /* Only update the file block number */
- lb->curr_block += max_entries * max_entries;
- }
- }
- put_bh(bh);
- return retval;
-
-}
-
-static int free_dind_blocks(handle_t *handle,
- struct inode *inode, __le32 i_data)
-{
- int i;
- __le32 *tmp_idata;
- struct buffer_head *bh;
- struct super_block *sb = inode->i_sb;
- unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
- int err;
-
- bh = ext4_sb_bread(sb, le32_to_cpu(i_data), 0);
- if (IS_ERR(bh))
- return PTR_ERR(bh);
-
- tmp_idata = (__le32 *)bh->b_data;
- for (i = 0; i < max_entries; i++) {
- if (tmp_idata[i]) {
- err = ext4_journal_ensure_credits(handle,
- EXT4_RESERVE_TRANS_BLOCKS,
- ext4_free_metadata_revoke_credits(sb, 1));
- if (err < 0) {
- put_bh(bh);
- return err;
- }
- ext4_free_blocks(handle, inode, NULL,
- le32_to_cpu(tmp_idata[i]), 1,
- EXT4_FREE_BLOCKS_METADATA |
- EXT4_FREE_BLOCKS_FORGET);
- }
- }
- put_bh(bh);
- err = ext4_journal_ensure_credits(handle, EXT4_RESERVE_TRANS_BLOCKS,
- ext4_free_metadata_revoke_credits(sb, 1));
- if (err < 0)
- return err;
- ext4_free_blocks(handle, inode, NULL, le32_to_cpu(i_data), 1,
- EXT4_FREE_BLOCKS_METADATA |
- EXT4_FREE_BLOCKS_FORGET);
- return 0;
-}
-
-static int free_tind_blocks(handle_t *handle,
- struct inode *inode, __le32 i_data)
-{
- int i, retval = 0;
- __le32 *tmp_idata;
- struct buffer_head *bh;
- unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
-
- bh = ext4_sb_bread(inode->i_sb, le32_to_cpu(i_data), 0);
- if (IS_ERR(bh))
- return PTR_ERR(bh);
-
- tmp_idata = (__le32 *)bh->b_data;
- for (i = 0; i < max_entries; i++) {
- if (tmp_idata[i]) {
- retval = free_dind_blocks(handle,
- inode, tmp_idata[i]);
- if (retval) {
- put_bh(bh);
- return retval;
- }
- }
- }
- put_bh(bh);
- retval = ext4_journal_ensure_credits(handle, EXT4_RESERVE_TRANS_BLOCKS,
- ext4_free_metadata_revoke_credits(inode->i_sb, 1));
- if (retval < 0)
- return retval;
- ext4_free_blocks(handle, inode, NULL, le32_to_cpu(i_data), 1,
- EXT4_FREE_BLOCKS_METADATA |
- EXT4_FREE_BLOCKS_FORGET);
- return 0;
-}
-
-static int free_ind_block(handle_t *handle, struct inode *inode, __le32 *i_data)
-{
- int retval;
-
- /* ei->i_data[EXT4_IND_BLOCK] */
- if (i_data[0]) {
- retval = ext4_journal_ensure_credits(handle,
- EXT4_RESERVE_TRANS_BLOCKS,
- ext4_free_metadata_revoke_credits(inode->i_sb, 1));
- if (retval < 0)
- return retval;
- ext4_free_blocks(handle, inode, NULL,
- le32_to_cpu(i_data[0]), 1,
- EXT4_FREE_BLOCKS_METADATA |
- EXT4_FREE_BLOCKS_FORGET);
- }
-
- /* ei->i_data[EXT4_DIND_BLOCK] */
- if (i_data[1]) {
- retval = free_dind_blocks(handle, inode, i_data[1]);
- if (retval)
- return retval;
- }
-
- /* ei->i_data[EXT4_TIND_BLOCK] */
- if (i_data[2]) {
- retval = free_tind_blocks(handle, inode, i_data[2]);
- if (retval)
- return retval;
- }
- return 0;
-}
-
-static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
- struct inode *tmp_inode)
-{
- int retval, retval2 = 0;
- __le32 i_data[3];
- struct ext4_inode_info *ei = EXT4_I(inode);
- struct ext4_inode_info *tmp_ei = EXT4_I(tmp_inode);
-
- /*
- * One credit accounted for writing the
- * i_data field of the original inode
- */
- retval = ext4_journal_ensure_credits(handle, 1, 0);
- if (retval < 0)
- goto err_out;
-
- i_data[0] = ei->i_data[EXT4_IND_BLOCK];
- i_data[1] = ei->i_data[EXT4_DIND_BLOCK];
- i_data[2] = ei->i_data[EXT4_TIND_BLOCK];
-
- down_write(&EXT4_I(inode)->i_data_sem);
- /*
- * if EXT4_STATE_EXT_MIGRATE is cleared a block allocation
- * happened after we started the migrate. We need to
- * fail the migrate
- */
- if (!ext4_test_inode_state(inode, EXT4_STATE_EXT_MIGRATE)) {
- retval = -EAGAIN;
- up_write(&EXT4_I(inode)->i_data_sem);
- goto err_out;
- } else
- ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
- /*
- * We have the extent map build with the tmp inode.
- * Now copy the i_data across
- */
- ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
- memcpy(ei->i_data, tmp_ei->i_data, sizeof(ei->i_data));
-
- /*
- * Update i_blocks with the new blocks that got
- * allocated while adding extents for extent index
- * blocks.
- *
- * While converting to extents we need not
- * update the original inode i_blocks for extent blocks
- * via quota APIs. The quota update happened via tmp_inode already.
- */
- spin_lock(&inode->i_lock);
- inode->i_blocks += tmp_inode->i_blocks;
- spin_unlock(&inode->i_lock);
- up_write(&EXT4_I(inode)->i_data_sem);
-
- /*
- * We mark the inode dirty after, because we decrement the
- * i_blocks when freeing the indirect meta-data blocks
- */
- retval = free_ind_block(handle, inode, i_data);
- retval2 = ext4_mark_inode_dirty(handle, inode);
- if (unlikely(retval2 && !retval))
- retval = retval2;
-
-err_out:
- return retval;
-}
-
-static int free_ext_idx(handle_t *handle, struct inode *inode,
- struct ext4_extent_idx *ix)
-{
- int i, retval = 0;
- ext4_fsblk_t block;
- struct buffer_head *bh;
- struct ext4_extent_header *eh;
-
- block = ext4_idx_pblock(ix);
- bh = ext4_sb_bread(inode->i_sb, block, 0);
- if (IS_ERR(bh))
- return PTR_ERR(bh);
-
- eh = (struct ext4_extent_header *)bh->b_data;
- if (eh->eh_depth != 0) {
- ix = EXT_FIRST_INDEX(eh);
- for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
- retval = free_ext_idx(handle, inode, ix);
- if (retval) {
- put_bh(bh);
- return retval;
- }
- }
- }
- put_bh(bh);
- retval = ext4_journal_ensure_credits(handle, EXT4_RESERVE_TRANS_BLOCKS,
- ext4_free_metadata_revoke_credits(inode->i_sb, 1));
- if (retval < 0)
- return retval;
- ext4_free_blocks(handle, inode, NULL, block, 1,
- EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
- return 0;
-}
-
-/*
- * Free the extent meta data blocks only
- */
-static int free_ext_block(handle_t *handle, struct inode *inode)
-{
- int i, retval = 0;
- struct ext4_inode_info *ei = EXT4_I(inode);
- struct ext4_extent_header *eh = (struct ext4_extent_header *)ei->i_data;
- struct ext4_extent_idx *ix;
- if (eh->eh_depth == 0)
- /*
- * No extra blocks allocated for extent meta data
- */
- return 0;
- ix = EXT_FIRST_INDEX(eh);
- for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
- retval = free_ext_idx(handle, inode, ix);
- if (retval)
- return retval;
- }
- return retval;
-}
-
-int ext4_ext_migrate(struct inode *inode)
-{
- struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
- handle_t *handle;
- int retval = 0, i;
- __le32 *i_data;
- struct ext4_inode_info *ei;
- struct inode *tmp_inode = NULL;
- struct migrate_struct lb;
- unsigned long max_entries;
- __u32 goal;
- uid_t owner[2];
-
- /*
- * If the filesystem does not support extents, or the inode
- * already is extent-based, error out.
- */
- if (!ext4_has_feature_extents(inode->i_sb) ||
- (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
- return -EINVAL;
-
- if (S_ISLNK(inode->i_mode) && inode->i_blocks == 0)
- /*
- * don't migrate fast symlink
- */
- return retval;
-
- percpu_down_write(&sbi->s_writepages_rwsem);
-
- /*
- * Worst case we can touch the allocation bitmaps, a bgd
- * block, and a block to link in the orphan list. We do need
- * need to worry about credits for modifying the quota inode.
- */
- handle = ext4_journal_start(inode, EXT4_HT_MIGRATE,
- 4 + EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb));
-
- if (IS_ERR(handle)) {
- retval = PTR_ERR(handle);
- goto out_unlock;
- }
- goal = (((inode->i_ino - 1) / EXT4_INODES_PER_GROUP(inode->i_sb)) *
- EXT4_INODES_PER_GROUP(inode->i_sb)) + 1;
- owner[0] = i_uid_read(inode);
- owner[1] = i_gid_read(inode);
- tmp_inode = ext4_new_inode(handle, d_inode(inode->i_sb->s_root),
- S_IFREG, NULL, goal, owner, 0);
- if (IS_ERR(tmp_inode)) {
- retval = PTR_ERR(tmp_inode);
- ext4_journal_stop(handle);
- goto out_unlock;
- }
- i_size_write(tmp_inode, i_size_read(inode));
- /*
- * Set the i_nlink to zero so it will be deleted later
- * when we drop inode reference.
- */
- clear_nlink(tmp_inode);
-
- ext4_ext_tree_init(handle, tmp_inode);
- ext4_orphan_add(handle, tmp_inode);
- ext4_journal_stop(handle);
-
- /*
- * start with one credit accounted for
- * superblock modification.
- *
- * For the tmp_inode we already have committed the
- * transaction that created the inode. Later as and
- * when we add extents we extent the journal
- */
- /*
- * Even though we take i_mutex we can still cause block
- * allocation via mmap write to holes. If we have allocated
- * new blocks we fail migrate. New block allocation will
- * clear EXT4_STATE_EXT_MIGRATE flag. The flag is updated
- * with i_data_sem held to prevent racing with block
- * allocation.
- */
- down_read(&EXT4_I(inode)->i_data_sem);
- ext4_set_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
- up_read((&EXT4_I(inode)->i_data_sem));
-
- handle = ext4_journal_start(inode, EXT4_HT_MIGRATE, 1);
- if (IS_ERR(handle)) {
- /*
- * It is impossible to update on-disk structures without
- * a handle, so just rollback in-core changes and live other
- * work to orphan_list_cleanup()
- */
- ext4_orphan_del(NULL, tmp_inode);
- retval = PTR_ERR(handle);
- goto out_tmp_inode;
- }
-
- ei = EXT4_I(inode);
- i_data = ei->i_data;
- memset(&lb, 0, sizeof(lb));
-
- /* 32 bit block address 4 bytes */
- max_entries = inode->i_sb->s_blocksize >> 2;
- for (i = 0; i < EXT4_NDIR_BLOCKS; i++) {
- if (i_data[i]) {
- retval = update_extent_range(handle, tmp_inode,
- le32_to_cpu(i_data[i]), &lb);
- if (retval)
- goto err_out;
- } else
- lb.curr_block++;
- }
- if (i_data[EXT4_IND_BLOCK]) {
- retval = update_ind_extent_range(handle, tmp_inode,
- le32_to_cpu(i_data[EXT4_IND_BLOCK]), &lb);
- if (retval)
- goto err_out;
- } else
- lb.curr_block += max_entries;
- if (i_data[EXT4_DIND_BLOCK]) {
- retval = update_dind_extent_range(handle, tmp_inode,
- le32_to_cpu(i_data[EXT4_DIND_BLOCK]), &lb);
- if (retval)
- goto err_out;
- } else
- lb.curr_block += max_entries * max_entries;
- if (i_data[EXT4_TIND_BLOCK]) {
- retval = update_tind_extent_range(handle, tmp_inode,
- le32_to_cpu(i_data[EXT4_TIND_BLOCK]), &lb);
- if (retval)
- goto err_out;
- }
- /*
- * Build the last extent
- */
- retval = finish_range(handle, tmp_inode, &lb);
-err_out:
- if (retval)
- /*
- * Failure case delete the extent information with the
- * tmp_inode
- */
- free_ext_block(handle, tmp_inode);
- else {
- retval = ext4_ext_swap_inode_data(handle, inode, tmp_inode);
- if (retval)
- /*
- * if we fail to swap inode data free the extent
- * details of the tmp inode
- */
- free_ext_block(handle, tmp_inode);
- }
-
- /* We mark the tmp_inode dirty via ext4_ext_tree_init. */
- retval = ext4_journal_ensure_credits(handle, 1, 0);
- if (retval < 0)
- goto out_stop;
- /*
- * Mark the tmp_inode as of size zero
- */
- i_size_write(tmp_inode, 0);
-
- /*
- * set the i_blocks count to zero
- * so that the ext4_evict_inode() does the
- * right job
- *
- * We don't need to take the i_lock because
- * the inode is not visible to user space.
- */
- tmp_inode->i_blocks = 0;
-
- /* Reset the extent details */
- ext4_ext_tree_init(handle, tmp_inode);
-out_stop:
- ext4_journal_stop(handle);
-out_tmp_inode:
- unlock_new_inode(tmp_inode);
- iput(tmp_inode);
-out_unlock:
- percpu_up_write(&sbi->s_writepages_rwsem);
- return retval;
-}
-
-/*
- * Migrate a simple extent-based inode to use the i_blocks[] array
- */
-int ext4_ind_migrate(struct inode *inode)
-{
- struct ext4_extent_header *eh;
- struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
- struct ext4_super_block *es = sbi->s_es;
- struct ext4_inode_info *ei = EXT4_I(inode);
- struct ext4_extent *ex;
- unsigned int i, len;
- ext4_lblk_t start, end;
- ext4_fsblk_t blk;
- handle_t *handle;
- int ret, ret2 = 0;
-
- if (!ext4_has_feature_extents(inode->i_sb) ||
- (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
- return -EINVAL;
-
- if (ext4_has_feature_bigalloc(inode->i_sb))
- return -EOPNOTSUPP;
-
- /*
- * In order to get correct extent info, force all delayed allocation
- * blocks to be allocated, otherwise delayed allocation blocks may not
- * be reflected and bypass the checks on extent header.
- */
- if (test_opt(inode->i_sb, DELALLOC))
- ext4_alloc_da_blocks(inode);
-
- percpu_down_write(&sbi->s_writepages_rwsem);
-
- handle = ext4_journal_start(inode, EXT4_HT_MIGRATE, 1);
- if (IS_ERR(handle)) {
- ret = PTR_ERR(handle);
- goto out_unlock;
- }
-
- down_write(&EXT4_I(inode)->i_data_sem);
- ret = ext4_ext_check_inode(inode);
- if (ret)
- goto errout;
-
- eh = ext_inode_hdr(inode);
- ex = EXT_FIRST_EXTENT(eh);
- if (ext4_blocks_count(es) > EXT4_MAX_BLOCK_FILE_PHYS ||
- eh->eh_depth != 0 || le16_to_cpu(eh->eh_entries) > 1) {
- ret = -EOPNOTSUPP;
- goto errout;
- }
- if (eh->eh_entries == 0)
- blk = len = start = end = 0;
- else {
- len = le16_to_cpu(ex->ee_len);
- blk = ext4_ext_pblock(ex);
- start = le32_to_cpu(ex->ee_block);
- end = start + len - 1;
- if (end >= EXT4_NDIR_BLOCKS) {
- ret = -EOPNOTSUPP;
- goto errout;
- }
- }
-
- ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
- memset(ei->i_data, 0, sizeof(ei->i_data));
- for (i = start; i <= end; i++)
- ei->i_data[i] = cpu_to_le32(blk++);
- ret2 = ext4_mark_inode_dirty(handle, inode);
- if (unlikely(ret2 && !ret))
- ret = ret2;
-errout:
- ext4_journal_stop(handle);
- up_write(&EXT4_I(inode)->i_data_sem);
-out_unlock:
- percpu_up_write(&sbi->s_writepages_rwsem);
- return ret;
-}