mirror of
https://github.com/torvalds/linux
synced 2024-09-06 18:01:05 +00:00
ext4: Fix reusing stale buffer heads from last failed mounting
Following process makes ext4 load stale buffer heads from last failed
mounting in a new mounting operation:
mount_bdev
ext4_fill_super
| ext4_load_and_init_journal
| ext4_load_journal
| jbd2_journal_load
| load_superblock
| journal_get_superblock
| set_buffer_verified(bh) // buffer head is verified
| jbd2_journal_recover // failed caused by EIO
| goto failed_mount3a // skip 'sb->s_root' initialization
deactivate_locked_super
kill_block_super
generic_shutdown_super
if (sb->s_root)
// false, skip ext4_put_super->invalidate_bdev->
// invalidate_mapping_pages->mapping_evict_folio->
// filemap_release_folio->try_to_free_buffers, which
// cannot drop buffer head.
blkdev_put
blkdev_put_whole
if (atomic_dec_and_test(&bdev->bd_openers))
// false, systemd-udev happens to open the device. Then
// blkdev_flush_mapping->kill_bdev->truncate_inode_pages->
// truncate_inode_folio->truncate_cleanup_folio->
// folio_invalidate->block_invalidate_folio->
// filemap_release_folio->try_to_free_buffers will be skipped,
// dropping buffer head is missed again.
Second mount:
ext4_fill_super
ext4_load_and_init_journal
ext4_load_journal
ext4_get_journal
jbd2_journal_init_inode
journal_init_common
bh = getblk_unmovable
bh = __find_get_block // Found stale bh in last failed mounting
journal->j_sb_buffer = bh
jbd2_journal_load
load_superblock
journal_get_superblock
if (buffer_verified(bh))
// true, skip journal->j_format_version = 2, value is 0
jbd2_journal_recover
do_one_pass
next_log_block += count_tags(journal, bh)
// According to journal_tag_bytes(), 'tag_bytes' calculating is
// affected by jbd2_has_feature_csum3(), jbd2_has_feature_csum3()
// returns false because 'j->j_format_version >= 2' is not true,
// then we get wrong next_log_block. The do_one_pass may exit
// early whenoccuring non JBD2_MAGIC_NUMBER in 'next_log_block'.
The filesystem is corrupted here, journal is partially replayed, and
new journal sequence number actually is already used by last mounting.
The invalidate_bdev() can drop all buffer heads even racing with bare
reading block device(eg. systemd-udev), so we can fix it by invalidating
bdev in error handling path in __ext4_fill_super().
Fetch a reproducer in [Link].
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217171
Fixes: 25ed6e8a54
("jbd2: enable journal clients to enable v2 checksumming")
Cc: stable@vger.kernel.org # v3.5
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230315013128.3911115-2-chengzhihao1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
parent
310ee0902b
commit
26fb529024
|
@ -1128,6 +1128,12 @@ static void ext4_blkdev_remove(struct ext4_sb_info *sbi)
|
|||
struct block_device *bdev;
|
||||
bdev = sbi->s_journal_bdev;
|
||||
if (bdev) {
|
||||
/*
|
||||
* Invalidate the journal device's buffers. We don't want them
|
||||
* floating about in memory - the physical journal device may
|
||||
* hotswapped, and it breaks the `ro-after' testing code.
|
||||
*/
|
||||
invalidate_bdev(bdev);
|
||||
ext4_blkdev_put(bdev);
|
||||
sbi->s_journal_bdev = NULL;
|
||||
}
|
||||
|
@ -1328,13 +1334,7 @@ static void ext4_put_super(struct super_block *sb)
|
|||
sync_blockdev(sb->s_bdev);
|
||||
invalidate_bdev(sb->s_bdev);
|
||||
if (sbi->s_journal_bdev && sbi->s_journal_bdev != sb->s_bdev) {
|
||||
/*
|
||||
* Invalidate the journal device's buffers. We don't want them
|
||||
* floating about in memory - the physical journal device may
|
||||
* hotswapped, and it breaks the `ro-after' testing code.
|
||||
*/
|
||||
sync_blockdev(sbi->s_journal_bdev);
|
||||
invalidate_bdev(sbi->s_journal_bdev);
|
||||
ext4_blkdev_remove(sbi);
|
||||
}
|
||||
|
||||
|
@ -5655,6 +5655,7 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
|
|||
brelse(sbi->s_sbh);
|
||||
ext4_blkdev_remove(sbi);
|
||||
out_fail:
|
||||
invalidate_bdev(sb->s_bdev);
|
||||
sb->s_fs_info = NULL;
|
||||
return err;
|
||||
}
|
||||
|
|
Loading…
Reference in a new issue