Commit 387c149b authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Fix a umount race 



Ensure that we unregister the bdi before kill_anon_super() calls
ida_remove() on our device name.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org
parent 9f557cd8

fs/nfs/super.c

+14 −1
Original line number Diff line number Diff line
@@ -243,6 +243,7 @@ static int nfs_show_stats(struct seq_file *, struct vfsmount *); 
static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);

static int nfs_xdev_get_sb(struct file_system_type *fs_type,

		int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);

static void nfs_put_super(struct super_block *);

static void nfs_kill_super(struct super_block *);

static int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
@@ -266,6 +267,7 @@ static const struct super_operations nfs_sops = { 
	.alloc_inode	= nfs_alloc_inode,

	.destroy_inode	= nfs_destroy_inode,

	.write_inode	= nfs_write_inode,

	.put_super	= nfs_put_super,

	.statfs		= nfs_statfs,

	.clear_inode	= nfs_clear_inode,

	.umount_begin	= nfs_umount_begin,
@@ -335,6 +337,7 @@ static const struct super_operations nfs4_sops = { 
	.alloc_inode	= nfs_alloc_inode,

	.destroy_inode	= nfs_destroy_inode,

	.write_inode	= nfs_write_inode,

	.put_super	= nfs_put_super,

	.statfs		= nfs_statfs,

	.clear_inode	= nfs4_clear_inode,

	.umount_begin	= nfs_umount_begin,
@@ -2257,6 +2260,17 @@ static int nfs_get_sb(struct file_system_type *fs_type, 
	goto out;

}



/*

 * Ensure that we unregister the bdi before kill_anon_super

 * releases the device name

 */

static void nfs_put_super(struct super_block *s)

{

	struct nfs_server *server = NFS_SB(s);



	bdi_unregister(&server->backing_dev_info);

}



/*

 * Destroy an NFS2/3 superblock

 */
@@ -2265,7 +2279,6 @@ static void nfs_kill_super(struct super_block *s) 
	struct nfs_server *server = NFS_SB(s);



	kill_anon_super(s);

	bdi_unregister(&server->backing_dev_info);

	nfs_fscache_release_super_cookie(s);

	nfs_free_server(server);

}