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| author | Jan Kara <jack@suse.cz> | 2016-02-18 14:03:03 +0100 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2016-02-18 14:03:03 +0100 |
| commit | ccf370e43e08cab4f8f13464c02c9aeffd8f0cd6 (patch) | |
| tree | ccd84f8d0cb3b1d932fea76976ee8cfbff0936fd /fs/quota | |
| parent | quota: Fix possible races during quota loading (diff) | |
| download | linux-ccf370e43e08cab4f8f13464c02c9aeffd8f0cd6.tar.xz linux-ccf370e43e08cab4f8f13464c02c9aeffd8f0cd6.zip | |
quota: Forbid Q_GETQUOTA and Q_GETNEXTQUOTA for frozen filesystem
Commit 7955118eafc4 (quota: Allow Q_GETQUOTA for frozen filesystem)
allowed Q_GETQUOTA call for frozen filesystem. It makes sense on the
first look but zero-day testing has shown that with this change ext4
warns about starting a transaction for frozen filesystem. This happens
because ext4_acquire_dquot() prepares for allocating space for new quota
structure. Although it would be possible to implement Q_GETQUOTA for
ext4 without allocating space for non-existent structures, the matter
further complicates because OCFS2 needs to update on-disk structure use
count when a new cluster node loads quota information from disk. So just
revert the change and forbid Q_GETQUOTA together with Q_GETNEXTQUOTA for
frozen filesystem. Add comment to quotactl_cmd_write() to save us from
repeating this excercise in a few years when I forget again.
Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/quota')
| -rw-r--r-- | fs/quota/quota.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/quota/quota.c b/fs/quota/quota.c index 8e297c92f7d4..0f10ee9892ce 100644 --- a/fs/quota/quota.c +++ b/fs/quota/quota.c @@ -765,11 +765,14 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id, /* Return 1 if 'cmd' will block on frozen filesystem */ static int quotactl_cmd_write(int cmd) { + /* + * We cannot allow Q_GETQUOTA and Q_GETNEXTQUOTA without write access + * as dquot_acquire() may allocate space for new structure and OCFS2 + * needs to increment on-disk use count. + */ switch (cmd) { case Q_GETFMT: case Q_GETINFO: - case Q_GETQUOTA: - case Q_GETNEXTQUOTA: case Q_SYNC: case Q_XGETQSTAT: case Q_XGETQSTATV: |