From: Jan Kara <jack@suse.cz>
To: Ted Tso <tytso@mit.edu>
Cc: <linux-ext4@vger.kernel.org>, Jan Kara <jack@suse.cz>
Subject: [PATCH] ext4: Make sanity check in mballoc more strict
Date: Thu, 28 Mar 2019 17:41:17 +0100 [thread overview]
Message-ID: <20190328164117.19148-1-jack@suse.cz> (raw)
Sanity check in mb_find_extent() only checked that returned extent does
not extend past blocksize * 8, however it should not extend past
EXT4_CLUSTERS_PER_GROUP(sb). This can happen when clusters_per_group <
blocksize * 8 and the tail of the bitmap is not properly filled by 1s
which happened e.g. when ancient kernels have grown the filesystem.
Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/ext4/mballoc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
As a background: We have a customer who has filesystems (created & apparently
resized by 3.0 or older kernels) and which make current kernels eventually barf
with errors but e2fsck says everything is fine. This patch makes mballoc code
detect issues earlier. I'll send appropriate e2fsck patch shortly.
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 6fb76d408093..8ef5f12bbee2 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1539,7 +1539,7 @@ static int mb_find_extent(struct ext4_buddy *e4b, int block,
ex->fe_len += 1 << order;
}
- if (ex->fe_start + ex->fe_len > (1 << (e4b->bd_blkbits + 3))) {
+ if (ex->fe_start + ex->fe_len > EXT4_CLUSTERS_PER_GROUP(e4b->bd_sb)) {
/* Should never happen! (but apparently sometimes does?!?) */
WARN_ON(1);
ext4_error(e4b->bd_sb, "corruption or bug in mb_find_extent "
--
2.16.4
next reply other threads:[~2019-03-28 16:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-28 16:41 Jan Kara [this message]
2019-04-06 22:35 ` [PATCH] ext4: Make sanity check in mballoc more strict Theodore Ts'o
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190328164117.19148-1-jack@suse.cz \
--to=jack@suse.cz \
--cc=linux-ext4@vger.kernel.org \
--cc=tytso@mit.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).