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Btrfs: fix subvolume mount by name problem when default mount subvolume is set
We create two subvolumes (meego_root and meego_home) in btrfs root directory. And set meego_root as default mount subvolume. After we remount btrfs, meego_root is mounted to top directory by default. Then when we try to mount meego_home (subvol=meego_home) to a subdirectory, it failed. The problem is when default mount subvolume is set to meego_root, we search meego_home in meego_root but can not find it. So the solution is to add a new mount option (subvolrootid) to specify subvol id of root and search subvol name in it. For our case, now we can use "-o subvolrootid=0,subvol=meego_home) to mount meego_home. Detail information can be found in meego bugzilla: https://bugs.meego.com/show_bug.cgi?id=15055 Signed-off-by: Zhong, Xin <xin.zhong@intel.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
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parent
13f2696f1d
commit
e15d054242
1 changed files with 33 additions and 9 deletions
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@ -159,7 +159,7 @@ enum {
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Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
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Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
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Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
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Opt_enospc_debug, Opt_err,
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Opt_enospc_debug, Opt_subvolrootid, Opt_err,
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};
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static match_table_t tokens = {
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@ -189,6 +189,7 @@ static match_table_t tokens = {
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{Opt_clear_cache, "clear_cache"},
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{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
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{Opt_enospc_debug, "enospc_debug"},
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{Opt_subvolrootid, "subvolrootid=%d"},
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{Opt_err, NULL},
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};
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@ -232,6 +233,7 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
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break;
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case Opt_subvol:
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case Opt_subvolid:
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case Opt_subvolrootid:
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case Opt_device:
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/*
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* These are parsed by btrfs_parse_early_options
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@ -388,7 +390,7 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
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*/
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static int btrfs_parse_early_options(const char *options, fmode_t flags,
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void *holder, char **subvol_name, u64 *subvol_objectid,
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struct btrfs_fs_devices **fs_devices)
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u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
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{
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substring_t args[MAX_OPT_ARGS];
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char *opts, *orig, *p;
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@ -429,6 +431,18 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags,
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*subvol_objectid = intarg;
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}
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break;
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case Opt_subvolrootid:
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intarg = 0;
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error = match_int(&args[0], &intarg);
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if (!error) {
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/* we want the original fs_tree */
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if (!intarg)
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*subvol_rootid =
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BTRFS_FS_TREE_OBJECTID;
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else
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*subvol_rootid = intarg;
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}
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break;
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case Opt_device:
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error = btrfs_scan_one_device(match_strdup(&args[0]),
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flags, holder, fs_devices);
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@ -736,6 +750,7 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
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fmode_t mode = FMODE_READ;
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char *subvol_name = NULL;
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u64 subvol_objectid = 0;
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u64 subvol_rootid = 0;
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int error = 0;
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if (!(flags & MS_RDONLY))
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@ -743,7 +758,7 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
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error = btrfs_parse_early_options(data, mode, fs_type,
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&subvol_name, &subvol_objectid,
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&fs_devices);
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&subvol_rootid, &fs_devices);
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if (error)
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return ERR_PTR(error);
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@ -807,15 +822,17 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
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s->s_flags |= MS_ACTIVE;
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}
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root = get_default_root(s, subvol_objectid);
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if (IS_ERR(root)) {
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error = PTR_ERR(root);
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deactivate_locked_super(s);
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goto error_free_subvol_name;
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}
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/* if they gave us a subvolume name bind mount into that */
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if (strcmp(subvol_name, ".")) {
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struct dentry *new_root;
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root = get_default_root(s, subvol_rootid);
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if (IS_ERR(root)) {
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error = PTR_ERR(root);
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deactivate_locked_super(s);
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goto error_free_subvol_name;
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}
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mutex_lock(&root->d_inode->i_mutex);
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new_root = lookup_one_len(subvol_name, root,
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strlen(subvol_name));
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@ -836,6 +853,13 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
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}
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dput(root);
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root = new_root;
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} else {
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root = get_default_root(s, subvol_objectid);
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if (IS_ERR(root)) {
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error = PTR_ERR(root);
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deactivate_locked_super(s);
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goto error_free_subvol_name;
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}
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}
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kfree(subvol_name);
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