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-rw-r--r--fs/btrfs/super.c42
1 files changed, 33 insertions, 9 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 58e7de9cc90c..0ac712efcdf2 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -159,7 +159,7 @@ enum {
159 Opt_compress_type, Opt_compress_force, Opt_compress_force_type, 159 Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
160 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard, 160 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
161 Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed, 161 Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
162 Opt_enospc_debug, Opt_err, 162 Opt_enospc_debug, Opt_subvolrootid, Opt_err,
163}; 163};
164 164
165static match_table_t tokens = { 165static match_table_t tokens = {
@@ -189,6 +189,7 @@ static match_table_t tokens = {
189 {Opt_clear_cache, "clear_cache"}, 189 {Opt_clear_cache, "clear_cache"},
190 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"}, 190 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
191 {Opt_enospc_debug, "enospc_debug"}, 191 {Opt_enospc_debug, "enospc_debug"},
192 {Opt_subvolrootid, "subvolrootid=%d"},
192 {Opt_err, NULL}, 193 {Opt_err, NULL},
193}; 194};
194 195
@@ -232,6 +233,7 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
232 break; 233 break;
233 case Opt_subvol: 234 case Opt_subvol:
234 case Opt_subvolid: 235 case Opt_subvolid:
236 case Opt_subvolrootid:
235 case Opt_device: 237 case Opt_device:
236 /* 238 /*
237 * These are parsed by btrfs_parse_early_options 239 * These are parsed by btrfs_parse_early_options
@@ -388,7 +390,7 @@ out:
388 */ 390 */
389static int btrfs_parse_early_options(const char *options, fmode_t flags, 391static int btrfs_parse_early_options(const char *options, fmode_t flags,
390 void *holder, char **subvol_name, u64 *subvol_objectid, 392 void *holder, char **subvol_name, u64 *subvol_objectid,
391 struct btrfs_fs_devices **fs_devices) 393 u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
392{ 394{
393 substring_t args[MAX_OPT_ARGS]; 395 substring_t args[MAX_OPT_ARGS];
394 char *opts, *orig, *p; 396 char *opts, *orig, *p;
@@ -429,6 +431,18 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags,
429 *subvol_objectid = intarg; 431 *subvol_objectid = intarg;
430 } 432 }
431 break; 433 break;
434 case Opt_subvolrootid:
435 intarg = 0;
436 error = match_int(&args[0], &intarg);
437 if (!error) {
438 /* we want the original fs_tree */
439 if (!intarg)
440 *subvol_rootid =
441 BTRFS_FS_TREE_OBJECTID;
442 else
443 *subvol_rootid = intarg;
444 }
445 break;
432 case Opt_device: 446 case Opt_device:
433 error = btrfs_scan_one_device(match_strdup(&args[0]), 447 error = btrfs_scan_one_device(match_strdup(&args[0]),
434 flags, holder, fs_devices); 448 flags, holder, fs_devices);
@@ -736,6 +750,7 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
736 fmode_t mode = FMODE_READ; 750 fmode_t mode = FMODE_READ;
737 char *subvol_name = NULL; 751 char *subvol_name = NULL;
738 u64 subvol_objectid = 0; 752 u64 subvol_objectid = 0;
753 u64 subvol_rootid = 0;
739 int error = 0; 754 int error = 0;
740 755
741 if (!(flags & MS_RDONLY)) 756 if (!(flags & MS_RDONLY))
@@ -743,7 +758,7 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
743 758
744 error = btrfs_parse_early_options(data, mode, fs_type, 759 error = btrfs_parse_early_options(data, mode, fs_type,
745 &subvol_name, &subvol_objectid, 760 &subvol_name, &subvol_objectid,
746 &fs_devices); 761 &subvol_rootid, &fs_devices);
747 if (error) 762 if (error)
748 return ERR_PTR(error); 763 return ERR_PTR(error);
749 764
@@ -807,15 +822,17 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
807 s->s_flags |= MS_ACTIVE; 822 s->s_flags |= MS_ACTIVE;
808 } 823 }
809 824
810 root = get_default_root(s, subvol_objectid);
811 if (IS_ERR(root)) {
812 error = PTR_ERR(root);
813 deactivate_locked_super(s);
814 goto error_free_subvol_name;
815 }
816 /* if they gave us a subvolume name bind mount into that */ 825 /* if they gave us a subvolume name bind mount into that */
817 if (strcmp(subvol_name, ".")) { 826 if (strcmp(subvol_name, ".")) {
818 struct dentry *new_root; 827 struct dentry *new_root;
828
829 root = get_default_root(s, subvol_rootid);
830 if (IS_ERR(root)) {
831 error = PTR_ERR(root);
832 deactivate_locked_super(s);
833 goto error_free_subvol_name;
834 }
835
819 mutex_lock(&root->d_inode->i_mutex); 836 mutex_lock(&root->d_inode->i_mutex);
820 new_root = lookup_one_len(subvol_name, root, 837 new_root = lookup_one_len(subvol_name, root,
821 strlen(subvol_name)); 838 strlen(subvol_name));
@@ -836,6 +853,13 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
836 } 853 }
837 dput(root); 854 dput(root);
838 root = new_root; 855 root = new_root;
856 } else {
857 root = get_default_root(s, subvol_objectid);
858 if (IS_ERR(root)) {
859 error = PTR_ERR(root);
860 deactivate_locked_super(s);
861 goto error_free_subvol_name;
862 }
839 } 863 }
840 864
841 kfree(subvol_name); 865 kfree(subvol_name);