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-rw-r--r--fs/quota/quota.c41
1 files changed, 27 insertions, 14 deletions
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index b299961..b34bdb2 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;
}
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