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authorJan Kara <jack@suse.cz>2016-02-18 16:03:03 +0300
committerJan Kara <jack@suse.cz>2016-02-18 16:03:03 +0300
commitccf370e43e08cab4f8f13464c02c9aeffd8f0cd6 (patch)
treeccd84f8d0cb3b1d932fea76976ee8cfbff0936fd /fs/quota/quota.c
parent044c9b6753a6b6cf486e16b53296b4707b35dbe3 (diff)
downloadlinux-ccf370e43e08cab4f8f13464c02c9aeffd8f0cd6.tar.xz
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/quota.c')
-rw-r--r--fs/quota/quota.c7
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: