quota: special case Q_SYNC without device name
The Q_SYNC command can be called without the path to a device, in which case
it iterates over all superblocks. Special case this variant directly in
sys_quotactl so that the other code always gets a superblock and doesn't
need to deal with this case.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index dcf7db9..9fde5cd 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -124,10 +124,17 @@
}
#endif
-static void sync_dquots(int type)
+static int quota_sync_all(int type)
{
struct super_block *sb;
int cnt;
+ int ret;
+
+ if (type >= MAXQUOTAS)
+ return -EINVAL;
+ ret = security_quotactl(Q_SYNC, type, 0, NULL);
+ if (ret)
+ return ret;
spin_lock(&sb_lock);
restart:
@@ -157,6 +164,8 @@
goto restart;
}
spin_unlock(&sb_lock);
+
+ return 0;
}
static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
@@ -322,12 +331,9 @@
case Q_SETQUOTA:
return quota_setquota(sb, type, id, addr);
case Q_SYNC:
- if (sb) {
- if (!sb->s_qcop->quota_sync)
- return -ENOSYS;
- sync_quota_sb(sb, type);
- } else
- sync_dquots(type);
+ if (!sb->s_qcop->quota_sync)
+ return -ENOSYS;
+ sync_quota_sb(sb, type);
return 0;
case Q_XQUOTAON:
case Q_XQUOTAOFF:
@@ -392,18 +398,26 @@
cmds = cmd >> SUBCMDSHIFT;
type = cmd & SUBCMDMASK;
- if (cmds != Q_SYNC || special) {
- sb = quotactl_block(special);
- if (IS_ERR(sb))
- return PTR_ERR(sb);
+ /*
+ * As a special case Q_SYNC can be called without a specific device.
+ * It will iterate all superblocks that have quota enabled and call
+ * the sync action on each of them.
+ */
+ if (!special) {
+ if (cmds == Q_SYNC)
+ return quota_sync_all(type);
+ return -ENODEV;
}
+ sb = quotactl_block(special);
+ if (IS_ERR(sb))
+ return PTR_ERR(sb);
+
ret = check_quotactl_valid(sb, type, cmds, id);
if (ret >= 0)
ret = do_quotactl(sb, type, cmds, id, addr);
- if (sb)
- drop_super(sb);
+ drop_super(sb);
return ret;
}