[PATCH 4.9 09/39] btrfs: export helpers for subvolume name/id resolution

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Marcos Paulo de Souza <mpdesouza@suse.com>

[ Upstream commit c0c907a47dccf2cf26251a8fb4a8e7a3bf79ce84 ]

The functions will be used outside of export.c and super.c to allow
resolving subvolume name from a given id, eg. for subvolume deletion by
id ioctl.

Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ split from the next patch ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/btrfs/ctree.h  | 2 ++
 fs/btrfs/export.c | 8 ++++----
 fs/btrfs/export.h | 5 +++++
 fs/btrfs/super.c  | 8 ++++----
 4 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 2bc37d03d4075..abfc090510480 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3261,6 +3261,8 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size);
 int btrfs_parse_options(struct btrfs_root *root, char *options,
 			unsigned long new_flags);
 int btrfs_sync_fs(struct super_block *sb, int wait);
+char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
+					  u64 subvol_objectid);
 
 static inline __printf(2, 3)
 void btrfs_no_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c
index 2513a7f533342..92f80ed642194 100644
--- a/fs/btrfs/export.c
+++ b/fs/btrfs/export.c
@@ -55,9 +55,9 @@ static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
 	return type;
 }
 
-static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
-				       u64 root_objectid, u32 generation,
-				       int check_generation)
+struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
+				u64 root_objectid, u32 generation,
+				int check_generation)
 {
 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 	struct btrfs_root *root;
@@ -150,7 +150,7 @@ static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
 	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
 }
 
-static struct dentry *btrfs_get_parent(struct dentry *child)
+struct dentry *btrfs_get_parent(struct dentry *child)
 {
 	struct inode *dir = d_inode(child);
 	struct btrfs_root *root = BTRFS_I(dir)->root;
diff --git a/fs/btrfs/export.h b/fs/btrfs/export.h
index 074348a95841f..7a305e5549991 100644
--- a/fs/btrfs/export.h
+++ b/fs/btrfs/export.h
@@ -16,4 +16,9 @@ struct btrfs_fid {
 	u64 parent_root_objectid;
 } __attribute__ ((packed));
 
+struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
+				u64 root_objectid, u32 generation,
+				int check_generation);
+struct dentry *btrfs_get_parent(struct dentry *child);
+
 #endif
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 9286603a6a98b..af5be060c651f 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -948,8 +948,8 @@ out:
 	return error;
 }
 
-static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
-					   u64 subvol_objectid)
+char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
+					  u64 subvol_objectid)
 {
 	struct btrfs_root *root = fs_info->tree_root;
 	struct btrfs_root *fs_root;
@@ -1430,8 +1430,8 @@ static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
 				goto out;
 			}
 		}
-		subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
-							    subvol_objectid);
+		subvol_name = btrfs_get_subvol_name_from_objectid(
+					btrfs_sb(mnt->mnt_sb), subvol_objectid);
 		if (IS_ERR(subvol_name)) {
 			root = ERR_CAST(subvol_name);
 			subvol_name = NULL;
-- 
2.25.1