[PATCH 4.10 09/69] orangefs: free superblock when mount fails

Greg Kroah-Hartman
2017-04-19T14:39:17Z

From: Martin Brandenburg <martin@omnibond.com>

commit 1ec1688c5360e14dde4094d6acbf7516bf6db37e upstream.

Otherwise lockdep says:

[ 1337.483798] ================================================
[ 1337.483999] [ BUG: lock held when returning to user space! ]
[ 1337.484252] 4.11.0-rc6 #19 Not tainted
[ 1337.484423] ------------------------------------------------
[ 1337.484626] mount/14766 is leaving the kernel with locks still held!
[ 1337.484841] 1 lock held by mount/14766:
[ 1337.485017] #0: (&type->s_umount_key#33/1){+.+.+.}, at: [<ffffffff8124171f>] sget_userns+0x2af/0x520

Caught by xfstests generic/413 which tried to mount with the unsupported
mount option dax. Then xfstests generic/422 ran sync which deadlocks.

Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Acked-by: Mike Marshall <hubcap@omnibond.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/orangefs/devorangefs-req.c | 9 +++++++--
fs/orangefs/orangefs-kernel.h | 1 +
fs/orangefs/super.c | 23 ++++++++++++++++-------
3 files changed, 24 insertions(+), 9 deletions(-)

--- a/fs/orangefs/devorangefs-req.c
+++ b/fs/orangefs/devorangefs-req.c
@@ -208,14 +208,19 @@ restart:
continue;
/*
* Skip ops whose filesystem we don't know about unless
- * it is being mounted.
+ * it is being mounted or unmounted. It is possible for
+ * a filesystem we don't know about to be unmounted if
+ * it fails to mount in the kernel after userspace has
+ * been sent the mount request.
*/
/* XXX: is there a better way to detect this? */
} else if (ret == -1 &&
!(op->upcall.type ==
ORANGEFS_VFS_OP_FS_MOUNT ||
op->upcall.type ==
- ORANGEFS_VFS_OP_GETATTR)) {
+ ORANGEFS_VFS_OP_GETATTR ||
+ op->upcall.type ==
+ ORANGEFS_VFS_OP_FS_UMOUNT)) {
gossip_debug(GOSSIP_DEV_DEBUG,
"orangefs: skipping op tag %llu %s\n",
llu(op->tag), get_opname_string(op));
--- a/fs/orangefs/orangefs-kernel.h
+++ b/fs/orangefs/orangefs-kernel.h
@@ -249,6 +249,7 @@ struct orangefs_sb_info_s {
char devname[ORANGEFS_MAX_SERVER_ADDR_LEN];
struct super_block *sb;
int mount_pending;
+ int no_list;
struct list_head list;
};

--- a/fs/orangefs/super.c
+++ b/fs/orangefs/super.c
@@ -493,7 +493,7 @@ struct dentry *orangefs_mount(struct fil

if (ret) {
d = ERR_PTR(ret);
- goto free_op;
+ goto free_sb_and_op;
}

/*
@@ -519,6 +519,9 @@ struct dentry *orangefs_mount(struct fil
spin_unlock(&orangefs_superblocks_lock);
op_release(new_op);

+ /* Must be removed from the list now. */
+ ORANGEFS_SB(sb)->no_list = 0;
+
if (orangefs_userspace_version >= 20906) {
new_op = op_alloc(ORANGEFS_VFS_OP_FEATURES);
if (!new_op)
@@ -533,6 +536,10 @@ struct dentry *orangefs_mount(struct fil

return dget(sb->s_root);

+free_sb_and_op:
+ /* Will call orangefs_kill_sb with sb not in list. */
+ ORANGEFS_SB(sb)->no_list = 1;
+ deactivate_locked_super(sb);
free_op:
gossip_err("orangefs_mount: mount request failed with %d\n", ret);
if (ret == -EINVAL) {
@@ -558,12 +565,14 @@ void orangefs_kill_sb(struct super_block
*/
orangefs_unmount_sb(sb);

- /* remove the sb from our list of orangefs specific sb's */
-
- spin_lock(&orangefs_superblocks_lock);
- __list_del_entry(&ORANGEFS_SB(sb)->list); /* not list_del_init */
- ORANGEFS_SB(sb)->list.prev = NULL;
- spin_unlock(&orangefs_superblocks_lock);
+ if (!ORANGEFS_SB(sb)->no_list) {
+ /* remove the sb from our list of orangefs specific sb's */
+ spin_lock(&orangefs_superblocks_lock);
+ /* not list_del_init */
+ __list_del_entry(&ORANGEFS_SB(sb)->list);
+ ORANGEFS_SB(sb)->list.prev = NULL;
+ spin_unlock(&orangefs_superblocks_lock);
+ }

/*
* make sure that ORANGEFS_DEV_REMOUNT_ALL loop that might've seen us