1 files changed, 27 insertions, 14 deletions

diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index b299961e1edb..b34bdb25490c 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -64,18 +64,15 @@ static int quota_sync_all(int type)
 }
 
 static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
-                         void __user *addr)
+                         struct path *path)
 {
-        char *pathname;
-        int ret = -ENOSYS;
-
-        pathname = getname(addr);
-        if (IS_ERR(pathname))
-                return PTR_ERR(pathname);
-        if (sb->s_qcop->quota_on)
-                ret = sb->s_qcop->quota_on(sb, type, id, pathname);
-        putname(pathname);
-        return ret;
+        if (!sb->s_qcop->quota_on && !sb->s_qcop->quota_on_meta)
+                return -ENOSYS;
+        if (sb->s_qcop->quota_on_meta)
+                return sb->s_qcop->quota_on_meta(sb, type, id);
+        if (IS_ERR(path))
+                return PTR_ERR(path);
+        return sb->s_qcop->quota_on(sb, type, id, path);
 }
 
 static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
@@ -241,7 +238,7 @@ static int quota_getxquota(struct super_block *sb, int type, qid_t id,
 
 /* Copy parameters and call proper function */
 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
-                       void __user *addr)
+                       void __user *addr, struct path *path)
 {
         int ret;
 
@@ -256,7 +253,7 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
 
         switch (cmd) {
         case Q_QUOTAON:
-                return quota_quotaon(sb, type, cmd, id, addr);
+                return quota_quotaon(sb, type, cmd, id, path);
         case Q_QUOTAOFF:
                 if (!sb->s_qcop->quota_off)
                         return -ENOSYS;
@@ -335,6 +332,7 @@ SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
 {
         uint cmds, type;
         struct super_block *sb = NULL;
+        struct path path, *pathp = NULL;
         int ret;
 
         cmds = cmd >> SUBCMDSHIFT;
@@ -351,12 +349,27 @@ SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
                 return -ENODEV;
         }
 
+        /*
+         * Path for quotaon has to be resolved before grabbing superblock
+         * because that gets s_umount sem which is also possibly needed by path
+         * resolution (think about autofs) and thus deadlocks could arise.
+         */
+        if (cmds == Q_QUOTAON) {
+                ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW, &path);
+                if (ret)
+                        pathp = ERR_PTR(ret);
+                else
+                        pathp = &path;
+        }
+
         sb = quotactl_block(special);
         if (IS_ERR(sb))
                 return PTR_ERR(sb);
 
-        ret = do_quotactl(sb, type, cmds, id, addr);
+        ret = do_quotactl(sb, type, cmds, id, addr, pathp);
 
         drop_super(sb);
+        if (pathp && !IS_ERR(pathp))
+                path_put(pathp);
         return ret;
 }