Re: [PATCH] ext4: fix directory index node split corruption
From: Jan Kara <jack@suse.cz>
Date: 2021-08-04 15:15:40
On Fri 30-07-21 14:24:03, Artem Blagodarenko wrote:
I send patch whose author is Denis Lukianov [off-list ref]
His messages can't reach this list somehow.
I only rebased it ontop of master's HEAD and tested that it fixes
the problem and reviewed.
----
Following commit b5776e7, a trivial sequential write of empty files to
an empty ext4 file system (with large_dir enabled) fails after just
over 26 million files. Depending on luck, file creation will give error
EEXIST or EUCLEAN.
Commit b5776e7 fixed the no-restart condition so that
ext4_handle_dirty_dx_node is always called, but it also broke the
restart condition. This is because when restart=1, the original
implementation correctly skipped do_split() but b5776e7 clobbered the
"if(restart)goto journal_error;" logic.
This complementary change protects do_split() from restart condition,
making it safe from both current and future ordering of goto statements
in earlier sections of the code.
Tested on 5.11.20 with handy testing script:
i = 0
while i <= 32000000:
print (i)
with open('tmpmnt/%d' % i, 'wb') as fout:
i += 1
Google-Bug-Id: 176345532
Fixes: b5776e7 ("ext4: fix potential htree index checksum corruption")Please use 12 characters from git commit when identifying it (7 characters is likely to become non-unique). Otherwise the fix looks good so feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Also I think you should include Ted in 'To' or 'CC' to make it more likely he sees the patch. Honza
quoted hunk ↗ jump to hunk
Signed-off-by: Denis Lukianov <redacted> Signed-off-by: Artem Blagodarenko <redacted> --- fs/ext4/namei.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 5fd56f616cf0..0bbff03d4167 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c@@ -2542,13 +2542,16 @@ static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname, goto journal_error; } } - de = do_split(handle, dir, &bh, frame, &fname->hinfo); - if (IS_ERR(de)) { - err = PTR_ERR(de); + if (!restart) { + de = do_split(handle, dir, &bh, frame, &fname->hinfo); + if (IS_ERR(de)) { + err = PTR_ERR(de); + goto cleanup; + } + err = add_dirent_to_buf(handle, fname, dir, inode, de, +bh); goto cleanup; } - err = add_dirent_to_buf(handle, fname, dir, inode, de, bh); - goto cleanup; journal_error: ext4_std_error(dir->i_sb, err); /* this is a no-op if err == 0 */-- 2.18.4
-- Jan Kara [off-list ref] SUSE Labs, CR