NFS: Fix the mount regression
This avoids the recent NFS mount regression (returning EBUSY when mounting the same filesystem twice with different parameters). The best I can do given the constraints appears to be to have the kernel first look for a superblock that matches both the fsid and the user-specified mount options, and then spawn off a new superblock if that search fails. Note that this is not the same as specifying nosharecache everywhere since nosharecache will never attempt to match an existing superblock. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Tested-by: Hua Zhong <hzhong@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Родитель
36ad4885c4
Коммит
e89a5a43b9
110
fs/nfs/super.c
110
fs/nfs/super.c
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@ -1303,34 +1303,6 @@ static void nfs_clone_super(struct super_block *sb,
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nfs_initialise_sb(sb);
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}
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static int nfs_set_super(struct super_block *s, void *_server)
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{
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struct nfs_server *server = _server;
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int ret;
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s->s_fs_info = server;
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ret = set_anon_super(s, server);
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if (ret == 0)
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server->s_dev = s->s_dev;
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return ret;
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}
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static int nfs_compare_super(struct super_block *sb, void *data)
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{
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struct nfs_server *server = data, *old = NFS_SB(sb);
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if (memcmp(&old->nfs_client->cl_addr,
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&server->nfs_client->cl_addr,
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sizeof(old->nfs_client->cl_addr)) != 0)
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return 0;
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/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
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if (old->flags & NFS_MOUNT_UNSHARED)
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return 0;
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if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
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return 0;
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return 1;
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}
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#define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
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static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
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@ -1359,9 +1331,46 @@ static int nfs_compare_mount_options(const struct super_block *s, const struct n
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goto Ebusy;
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if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
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goto Ebusy;
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return 0;
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return 1;
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Ebusy:
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return -EBUSY;
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return 0;
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}
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struct nfs_sb_mountdata {
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struct nfs_server *server;
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int mntflags;
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};
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static int nfs_set_super(struct super_block *s, void *data)
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{
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struct nfs_sb_mountdata *sb_mntdata = data;
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struct nfs_server *server = sb_mntdata->server;
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int ret;
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s->s_flags = sb_mntdata->mntflags;
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s->s_fs_info = server;
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ret = set_anon_super(s, server);
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if (ret == 0)
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server->s_dev = s->s_dev;
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return ret;
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}
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static int nfs_compare_super(struct super_block *sb, void *data)
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{
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struct nfs_sb_mountdata *sb_mntdata = data;
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struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
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int mntflags = sb_mntdata->mntflags;
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if (memcmp(&old->nfs_client->cl_addr,
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&server->nfs_client->cl_addr,
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sizeof(old->nfs_client->cl_addr)) != 0)
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return 0;
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/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
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if (old->flags & NFS_MOUNT_UNSHARED)
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return 0;
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if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
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return 0;
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return nfs_compare_mount_options(sb, server, mntflags);
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}
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static int nfs_get_sb(struct file_system_type *fs_type,
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@ -1373,6 +1382,9 @@ static int nfs_get_sb(struct file_system_type *fs_type,
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struct nfs_mount_data *data = raw_data;
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struct dentry *mntroot;
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int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
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struct nfs_sb_mountdata sb_mntdata = {
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.mntflags = flags,
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};
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int error;
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/* Validate the mount data */
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@ -1386,28 +1398,25 @@ static int nfs_get_sb(struct file_system_type *fs_type,
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error = PTR_ERR(server);
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goto out;
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}
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sb_mntdata.server = server;
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if (server->flags & NFS_MOUNT_UNSHARED)
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compare_super = NULL;
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/* Get a superblock - note that we may end up sharing one that already exists */
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s = sget(fs_type, compare_super, nfs_set_super, server);
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s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
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if (IS_ERR(s)) {
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error = PTR_ERR(s);
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goto out_err_nosb;
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}
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if (s->s_fs_info != server) {
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error = nfs_compare_mount_options(s, server, flags);
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nfs_free_server(server);
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server = NULL;
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if (error < 0)
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goto error_splat_super;
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}
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if (!s->s_root) {
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/* initial superblock/root creation */
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s->s_flags = flags;
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nfs_fill_super(s, data);
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}
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@ -1460,6 +1469,9 @@ static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
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struct nfs_server *server;
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struct dentry *mntroot;
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int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
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struct nfs_sb_mountdata sb_mntdata = {
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.mntflags = flags,
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};
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int error;
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dprintk("--> nfs_xdev_get_sb()\n");
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@ -1470,28 +1482,25 @@ static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
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error = PTR_ERR(server);
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goto out_err_noserver;
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}
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sb_mntdata.server = server;
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if (server->flags & NFS_MOUNT_UNSHARED)
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compare_super = NULL;
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/* Get a superblock - note that we may end up sharing one that already exists */
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s = sget(&nfs_fs_type, compare_super, nfs_set_super, server);
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s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
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if (IS_ERR(s)) {
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error = PTR_ERR(s);
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goto out_err_nosb;
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}
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if (s->s_fs_info != server) {
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error = nfs_compare_mount_options(s, server, flags);
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nfs_free_server(server);
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server = NULL;
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if (error < 0)
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goto error_splat_super;
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}
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if (!s->s_root) {
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/* initial superblock/root creation */
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s->s_flags = flags;
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nfs_clone_super(s, data->sb);
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}
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@ -1729,6 +1738,9 @@ static int nfs4_get_sb(struct file_system_type *fs_type,
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struct dentry *mntroot;
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char *mntpath = NULL, *hostname = NULL, *ip_addr = NULL;
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int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
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struct nfs_sb_mountdata sb_mntdata = {
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.mntflags = flags,
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};
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int error;
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/* Validate the mount data */
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@ -1744,12 +1756,13 @@ static int nfs4_get_sb(struct file_system_type *fs_type,
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error = PTR_ERR(server);
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goto out;
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}
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sb_mntdata.server = server;
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if (server->flags & NFS4_MOUNT_UNSHARED)
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compare_super = NULL;
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/* Get a superblock - note that we may end up sharing one that already exists */
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s = sget(fs_type, compare_super, nfs_set_super, server);
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s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
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if (IS_ERR(s)) {
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error = PTR_ERR(s);
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goto out_free;
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@ -1762,7 +1775,6 @@ static int nfs4_get_sb(struct file_system_type *fs_type,
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if (!s->s_root) {
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/* initial superblock/root creation */
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s->s_flags = flags;
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nfs4_fill_super(s);
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}
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@ -1816,6 +1828,9 @@ static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
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struct nfs_server *server;
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struct dentry *mntroot;
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int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
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struct nfs_sb_mountdata sb_mntdata = {
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.mntflags = flags,
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};
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int error;
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dprintk("--> nfs4_xdev_get_sb()\n");
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@ -1826,12 +1841,13 @@ static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
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error = PTR_ERR(server);
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goto out_err_noserver;
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}
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sb_mntdata.server = server;
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if (server->flags & NFS4_MOUNT_UNSHARED)
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compare_super = NULL;
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/* Get a superblock - note that we may end up sharing one that already exists */
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s = sget(&nfs_fs_type, compare_super, nfs_set_super, server);
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s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
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if (IS_ERR(s)) {
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error = PTR_ERR(s);
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goto out_err_nosb;
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@ -1844,7 +1860,6 @@ static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
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if (!s->s_root) {
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/* initial superblock/root creation */
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s->s_flags = flags;
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nfs4_clone_super(s, data->sb);
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}
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@ -1887,6 +1902,9 @@ static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
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struct dentry *mntroot;
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struct nfs_fh mntfh;
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int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
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struct nfs_sb_mountdata sb_mntdata = {
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.mntflags = flags,
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};
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int error;
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dprintk("--> nfs4_referral_get_sb()\n");
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@ -1897,12 +1915,13 @@ static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
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error = PTR_ERR(server);
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goto out_err_noserver;
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}
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sb_mntdata.server = server;
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if (server->flags & NFS4_MOUNT_UNSHARED)
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compare_super = NULL;
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/* Get a superblock - note that we may end up sharing one that already exists */
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s = sget(&nfs_fs_type, compare_super, nfs_set_super, server);
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s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
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if (IS_ERR(s)) {
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error = PTR_ERR(s);
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goto out_err_nosb;
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@ -1915,7 +1934,6 @@ static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
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if (!s->s_root) {
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/* initial superblock/root creation */
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s->s_flags = flags;
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nfs4_fill_super(s);
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}
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