From: Theodore Ts'o tytso@mit.edu
mainline inclusion from mainline-5.12-rc1 commit b5776e7524af category: bugfix bugzilla: 50217 CVE: NA
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In the case where we need to do an interior node split, and immediately afterwards, we are unable to allocate a new directory leaf block due to ENOSPC, the directory index checksum's will not be filled in correctly (and indeed, will not be correctly journalled).
This looks like a bug that was introduced when we added largedir support. The original code doesn't make any sense (and should have been caught in code review), but it was hidden because most of the time, the index node checksum will be set by do_split(). But if do_split bails out due to ENOSPC, then ext4_handle_dirty_dx_node() won't get called, and so the directory index checksum field will not get set, leading to:
EXT4-fs error (device sdb): dx_probe:858: inode #6635543: block 4022: comm nfsd: Directory index failed checksum
Google-Bug-Id: 176345532 Fixes: e08ac99fa2a2 ("ext4: add largedir feature") Cc: Artem Blagodarenko artem.blagodarenko@gmail.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: zhangyi (F) yi.zhang@huawei.com Reviewed-by: Yang Erkun yangerkun@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- fs/ext4/namei.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 0969b83eb55f..020b5ace6284 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -2288,11 +2288,10 @@ static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname, (frame - 1)->bh); if (err) goto journal_error; - if (restart) { - err = ext4_handle_dirty_dx_node(handle, dir, - frame->bh); + err = ext4_handle_dirty_dx_node(handle, dir, + frame->bh); + if (err) goto journal_error; - } } else { struct dx_root *dxroot; memcpy((char *) entries2, (char *) entries,