This is a note to let you know that I've just added the patch titled ext4: fix reserved cluster accounting in __es_remove_extent() to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ext4-fix-reserved-cluster-accounting-in-__es_remove_extent.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 1da18e38cb97e9521e93d63034521a9649524f64 Mon Sep 17 00:00:00 2001 From: Ye Bin <yebin10@xxxxxxxxxx> Date: Thu, 8 Dec 2022 11:34:24 +0800 Subject: ext4: fix reserved cluster accounting in __es_remove_extent() From: Ye Bin <yebin10@xxxxxxxxxx> commit 1da18e38cb97e9521e93d63034521a9649524f64 upstream. When bigalloc is enabled, reserved cluster accounting for delayed allocation is handled in extent_status.c. With a corrupted file system, it's possible for this accounting to be incorrect, dsicovered by Syzbot: EXT4-fs error (device loop0): ext4_validate_block_bitmap:398: comm rep: bg 0: block 5: invalid block bitmap EXT4-fs (loop0): Delayed block allocation failed for inode 18 at logical offset 0 with max blocks 32 with error 28 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs (loop0): Total free blocks count 0 EXT4-fs (loop0): Free/Dirty block details EXT4-fs (loop0): free_blocks=0 EXT4-fs (loop0): dirty_blocks=32 EXT4-fs (loop0): Block reservation details EXT4-fs (loop0): i_reserved_data_blocks=2 EXT4-fs (loop0): Inode 18 (00000000845cd634): i_reserved_data_blocks (1) not cleared! Above issue happens as follows: Assume: sbi->s_cluster_ratio = 16 Step1: Insert delay block [0, 31] -> ei->i_reserved_data_blocks=2 Step2: ext4_writepages mpage_map_and_submit_extent -> return failed mpage_release_unused_pages -> to release [0, 30] ext4_es_remove_extent -> remove lblk=0 end=30 __es_remove_extent -> len1=0 len2=31-30=1 __es_remove_extent: ... if (len2 > 0) { ... if (len1 > 0) { ... } else { es->es_lblk = end + 1; es->es_len = len2; ... } if (count_reserved) count_rsvd(inode, lblk, ...); goto out; -> will return but didn't calculate 'reserved' ... Step3: ext4_destroy_inode -> trigger "i_reserved_data_blocks (1) not cleared!" To solve above issue if 'len2>0' call 'get_rsvd()' before goto out. Reported-by: syzbot+05a0f0ccab4a25626e38@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 8fcc3a580651 ("ext4: rework reserved cluster accounting when invalidating pages") Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx> Reviewed-by: Eric Whitney <enwlinux@xxxxxxxxx> Link: https://lore.kernel.org/r/20221208033426.1832460-2-yebin@xxxxxxxxxxxxxxx Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Cc: stable@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/ext4/extents_status.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/ext4/extents_status.c +++ b/fs/ext4/extents_status.c @@ -1372,7 +1372,7 @@ retry: if (count_reserved) count_rsvd(inode, lblk, orig_es.es_len - len1 - len2, &orig_es, &rc); - goto out; + goto out_get_reserved; } if (len1 > 0) { @@ -1414,6 +1414,7 @@ retry: } } +out_get_reserved: if (count_reserved) *reserved = get_rsvd(inode, end, es, &rc); out: Patches currently in stable-queue which might be from yebin10@xxxxxxxxxx are queue-5.15/ext4-fix-reserved-cluster-accounting-in-__es_remove_extent.patch