Following process may lead to fs corruption:
1. ext4_create(dir/foo)
ext4_add_nondir
ext4_add_entry
ext4_dx_add_entry
a. add_dirent_to_buf
ext4_mark_inode_dirty
ext4_handle_dirty_metadata // dir inode bh is recorded into journal
b. ext4_append // dx_get_count(entries) == dx_get_limit(entries)
ext4_bread(EXT4_GET_BLOCKS_CREATE)
ext4_getblk
ext4_map_blocks
ext4_ext_map_blocks
ext4_mb_new_blocks
dquot_alloc_block
dquot_alloc_space_nodirty
inode_add_bytes // update dir's i_blocks
ext4_ext_insert_extent
ext4_ext_dirty // record extent bh into journal
ext4_handle_dirty_metadata(bh)
// record new block into journal
inode->i_size += inode->i_sb->s_blocksize // new size(in mem)
c. ext4_handle_dirty_dx_node(bh2)
// record dir's new block(dx_node) into journal
d. ext4_handle_dirty_dx_node((frame - 1)->bh)
e. ext4_handle_dirty_dx_node(frame->bh)
f. do_split // ret err!
g. add_dirent_to_buf
ext4_mark_inode_dirty(dir) // update raw_inode on disk(skipped)
2. fsck -a /dev/sdb
drop last block(dx_node) which beyonds dir's i_size.
/dev/sdb: recovering journal
/dev/sdb contains a file system with errors, check forced.
/dev/sdb: Inode 12, end of extent exceeds allowed value
(logical block 128, physical block 3938, len 1)
3. fsck -fn /dev/sdb
dx_node->entry[i].blk > dir->i_size
Pass 2: Checking directory structure
Problem in HTREE directory inode 12 (/dir): bad block number 128.
Clear HTree index? no
Problem in HTREE directory inode 12: block #3 has invalid depth (2)
Problem in HTREE directory inode 12: block #3 has bad max hash
Problem in HTREE directory inode 12: block #3 not referenced
Fix it by marking inode dirty directly inside ext4_append().
Fetch a reproducer in [Link].
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216466
CC: [email protected]
Signed-off-by: Zhihao Cheng <[email protected]>
---
v1->v2: mark inode dirty inside ext4_append().
fs/ext4/namei.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 3a31b662f661..0d0e41d2dee8 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -85,15 +85,20 @@ static struct buffer_head *ext4_append(handle_t *handle,
return bh;
inode->i_size += inode->i_sb->s_blocksize;
EXT4_I(inode)->i_disksize = inode->i_size;
+ err = ext4_mark_inode_dirty(handle, inode);
+ if (err)
+ goto out;
BUFFER_TRACE(bh, "get_write_access");
err = ext4_journal_get_write_access(handle, inode->i_sb, bh,
EXT4_JTR_NONE);
- if (err) {
- brelse(bh);
- ext4_std_error(inode->i_sb, err);
- return ERR_PTR(err);
- }
+ if (err)
+ goto out;
return bh;
+
+out:
+ brelse(bh);
+ ext4_std_error(inode->i_sb, err);
+ return ERR_PTR(err);
}
static int ext4_dx_csum_verify(struct inode *inode,
--
2.31.1
On Sun 11-09-22 12:52:04, Zhihao Cheng wrote:
> Following process may lead to fs corruption:
> 1. ext4_create(dir/foo)
> ext4_add_nondir
> ext4_add_entry
> ext4_dx_add_entry
> a. add_dirent_to_buf
> ext4_mark_inode_dirty
> ext4_handle_dirty_metadata // dir inode bh is recorded into journal
> b. ext4_append // dx_get_count(entries) == dx_get_limit(entries)
> ext4_bread(EXT4_GET_BLOCKS_CREATE)
> ext4_getblk
> ext4_map_blocks
> ext4_ext_map_blocks
> ext4_mb_new_blocks
> dquot_alloc_block
> dquot_alloc_space_nodirty
> inode_add_bytes // update dir's i_blocks
> ext4_ext_insert_extent
> ext4_ext_dirty // record extent bh into journal
> ext4_handle_dirty_metadata(bh)
> // record new block into journal
> inode->i_size += inode->i_sb->s_blocksize // new size(in mem)
> c. ext4_handle_dirty_dx_node(bh2)
> // record dir's new block(dx_node) into journal
> d. ext4_handle_dirty_dx_node((frame - 1)->bh)
> e. ext4_handle_dirty_dx_node(frame->bh)
> f. do_split // ret err!
> g. add_dirent_to_buf
> ext4_mark_inode_dirty(dir) // update raw_inode on disk(skipped)
> 2. fsck -a /dev/sdb
> drop last block(dx_node) which beyonds dir's i_size.
> /dev/sdb: recovering journal
> /dev/sdb contains a file system with errors, check forced.
> /dev/sdb: Inode 12, end of extent exceeds allowed value
> (logical block 128, physical block 3938, len 1)
> 3. fsck -fn /dev/sdb
> dx_node->entry[i].blk > dir->i_size
> Pass 2: Checking directory structure
> Problem in HTREE directory inode 12 (/dir): bad block number 128.
> Clear HTree index? no
> Problem in HTREE directory inode 12: block #3 has invalid depth (2)
> Problem in HTREE directory inode 12: block #3 has bad max hash
> Problem in HTREE directory inode 12: block #3 not referenced
>
> Fix it by marking inode dirty directly inside ext4_append().
> Fetch a reproducer in [Link].
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=216466
> CC: [email protected]
> Signed-off-by: Zhihao Cheng <[email protected]>
Thanks! The patch looks good. Feel free to add:
Reviewed-by: Jan Kara <[email protected]>
Honza
> ---
> v1->v2: mark inode dirty inside ext4_append().
> fs/ext4/namei.c | 15 ++++++++++-----
> 1 file changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
> index 3a31b662f661..0d0e41d2dee8 100644
> --- a/fs/ext4/namei.c
> +++ b/fs/ext4/namei.c
> @@ -85,15 +85,20 @@ static struct buffer_head *ext4_append(handle_t *handle,
> return bh;
> inode->i_size += inode->i_sb->s_blocksize;
> EXT4_I(inode)->i_disksize = inode->i_size;
> + err = ext4_mark_inode_dirty(handle, inode);
> + if (err)
> + goto out;
> BUFFER_TRACE(bh, "get_write_access");
> err = ext4_journal_get_write_access(handle, inode->i_sb, bh,
> EXT4_JTR_NONE);
> - if (err) {
> - brelse(bh);
> - ext4_std_error(inode->i_sb, err);
> - return ERR_PTR(err);
> - }
> + if (err)
> + goto out;
> return bh;
> +
> +out:
> + brelse(bh);
> + ext4_std_error(inode->i_sb, err);
> + return ERR_PTR(err);
> }
>
> static int ext4_dx_csum_verify(struct inode *inode,
> --
> 2.31.1
>
--
Jan Kara <[email protected]>
SUSE Labs, CR
On Sun, 11 Sep 2022 12:52:04 +0800, Zhihao Cheng wrote:
> Following process may lead to fs corruption:
> 1. ext4_create(dir/foo)
> ext4_add_nondir
> ext4_add_entry
> ext4_dx_add_entry
> a. add_dirent_to_buf
> ext4_mark_inode_dirty
> ext4_handle_dirty_metadata // dir inode bh is recorded into journal
> b. ext4_append // dx_get_count(entries) == dx_get_limit(entries)
> ext4_bread(EXT4_GET_BLOCKS_CREATE)
> ext4_getblk
> ext4_map_blocks
> ext4_ext_map_blocks
> ext4_mb_new_blocks
> dquot_alloc_block
> dquot_alloc_space_nodirty
> inode_add_bytes // update dir's i_blocks
> ext4_ext_insert_extent
> ext4_ext_dirty // record extent bh into journal
> ext4_handle_dirty_metadata(bh)
> // record new block into journal
> inode->i_size += inode->i_sb->s_blocksize // new size(in mem)
> c. ext4_handle_dirty_dx_node(bh2)
> // record dir's new block(dx_node) into journal
> d. ext4_handle_dirty_dx_node((frame - 1)->bh)
> e. ext4_handle_dirty_dx_node(frame->bh)
> f. do_split // ret err!
> g. add_dirent_to_buf
> ext4_mark_inode_dirty(dir) // update raw_inode on disk(skipped)
> 2. fsck -a /dev/sdb
> drop last block(dx_node) which beyonds dir's i_size.
> /dev/sdb: recovering journal
> /dev/sdb contains a file system with errors, check forced.
> /dev/sdb: Inode 12, end of extent exceeds allowed value
> (logical block 128, physical block 3938, len 1)
> 3. fsck -fn /dev/sdb
> dx_node->entry[i].blk > dir->i_size
> Pass 2: Checking directory structure
> Problem in HTREE directory inode 12 (/dir): bad block number 128.
> Clear HTree index? no
> Problem in HTREE directory inode 12: block #3 has invalid depth (2)
> Problem in HTREE directory inode 12: block #3 has bad max hash
> Problem in HTREE directory inode 12: block #3 not referenced
>
> [...]
Applied, thanks!
[1/1] ext4: Fix dir corruption when ext4_dx_add_entry() fails
commit: 7a3584fd605e6a72036c5759a6e9ed2c46d14899
Best regards,
--
Theodore Ts'o <[email protected]>