From 387c149b54b4321cbc790dadbd4f8eedb5a90468 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 3 Feb 2010 08:27:35 -0500 Subject: [PATCH] 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: Trond Myklebust Cc: stable@kernel.org --- fs/nfs/super.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/fs/nfs/super.c b/fs/nfs/super.c index ce907efc5508..f1afee4eea77 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -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 @@ error_splat_super: 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); }