From: Ye Bin <yebin10@xxxxxxxxxx> commit 082cd4ec240b8734a82a89ffb890216ac98fec68 upstream. We got follow bug_on when run fsstress with injecting IO fault: [130747.323114] kernel BUG at fs/ext4/extents_status.c:762! [130747.323117] Internal error: Oops - BUG: 0 [#1] SMP ...... [130747.334329] Call trace: [130747.334553] ext4_es_cache_extent+0x150/0x168 [ext4] [130747.334975] ext4_cache_extents+0x64/0xe8 [ext4] [130747.335368] ext4_find_extent+0x300/0x330 [ext4] [130747.335759] ext4_ext_map_blocks+0x74/0x1178 [ext4] [130747.336179] ext4_map_blocks+0x2f4/0x5f0 [ext4] [130747.336567] ext4_mpage_readpages+0x4a8/0x7a8 [ext4] [130747.336995] ext4_readpage+0x54/0x100 [ext4] [130747.337359] generic_file_buffered_read+0x410/0xae8 [130747.337767] generic_file_read_iter+0x114/0x190 [130747.338152] ext4_file_read_iter+0x5c/0x140 [ext4] [130747.338556] __vfs_read+0x11c/0x188 [130747.338851] vfs_read+0x94/0x150 [130747.339110] ksys_read+0x74/0xf0 This patch's modification is according to Jan Kara's suggestion in: https://patchwork.ozlabs.org/project/linux-ext4/patch/20210428085158.3728201-1-yebin10@xxxxxxxxxx/ "I see. Now I understand your patch. Honestly, seeing how fragile is trying to fix extent tree after split has failed in the middle, I would probably go even further and make sure we fix the tree properly in case of ENOSPC and EDQUOT (those are easily user triggerable). Anything else indicates a HW problem or fs corruption so I'd rather leave the extent tree as is and don't try to fix it (which also means we will not create overlapping extents)." Cc: stable@xxxxxxxxxx Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx> Reviewed-by: Jan Kara <jack@xxxxxxx> Link: https://lore.kernel.org/r/20210506141042.3298679-1-yebin10@xxxxxxxxxx Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/ext4/extents.c | 43 +++++++++++++++++++++++-------------------- 1 file changed, 23 insertions(+), 20 deletions(-) --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3206,7 +3206,10 @@ static int ext4_split_extent_at(handle_t ext4_ext_mark_unwritten(ex2); err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags); - if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) { + if (err != -ENOSPC && err != -EDQUOT) + goto out; + + if (EXT4_EXT_MAY_ZEROOUT & split_flag) { if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) { if (split_flag & EXT4_EXT_DATA_VALID1) { err = ext4_ext_zeroout(inode, ex2); @@ -3232,25 +3235,22 @@ static int ext4_split_extent_at(handle_t ext4_ext_pblock(&orig_ex)); } - if (err) - goto fix_extent_len; - /* update the extent length and mark as initialized */ - ex->ee_len = cpu_to_le16(ee_len); - ext4_ext_try_to_merge(handle, inode, path, ex); - err = ext4_ext_dirty(handle, inode, path + path->p_depth); - if (err) - goto fix_extent_len; - - /* update extent status tree */ - err = ext4_zeroout_es(inode, &zero_ex); - - goto out; - } else if (err) - goto fix_extent_len; - -out: - ext4_ext_show_leaf(inode, path); - return err; + if (!err) { + /* update the extent length and mark as initialized */ + ex->ee_len = cpu_to_le16(ee_len); + ext4_ext_try_to_merge(handle, inode, path, ex); + err = ext4_ext_dirty(handle, inode, path + path->p_depth); + if (!err) + /* update extent status tree */ + err = ext4_zeroout_es(inode, &zero_ex); + /* If we failed at this point, we don't know in which + * state the extent tree exactly is so don't try to fix + * length of the original extent as it may do even more + * damage. + */ + goto out; + } + } fix_extent_len: ex->ee_len = orig_ex.ee_len; @@ -3260,6 +3260,9 @@ fix_extent_len: */ ext4_ext_dirty(handle, inode, path + path->p_depth); return err; +out: + ext4_ext_show_leaf(inode, path); + return err; } /*
