1 files changed, 80 insertions, 78 deletions

diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c
index 4b8691607373..230d9326b685 100644
--- a/fs/btrfs/export.c
+++ b/fs/btrfs/export.c
@@ -1,11 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+
 #include <linux/fs.h>
 #include <linux/types.h>
 #include "ctree.h"
 #include "disk-io.h"
 #include "btrfs_inode.h"
-#include "print-tree.h"
 #include "export.h"
-#include "compat.h"
+#include "accessors.h"
+#include "super.h"
 
 #define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, \
 						 parent_objectid) / 4)
@@ -21,7 +23,11 @@ static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
 	int type;
 
 	if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
-		*max_len = BTRFS_FID_SIZE_CONNECTABLE;
+		if (btrfs_root_id(BTRFS_I(inode)->root) !=
+		    btrfs_root_id(BTRFS_I(parent)->root))
+			*max_len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
+		else
+			*max_len = BTRFS_FID_SIZE_CONNECTABLE;
 		return FILEID_INVALID;
 	} else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
 		*max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
@@ -31,18 +37,20 @@ static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
 	len  = BTRFS_FID_SIZE_NON_CONNECTABLE;
 	type = FILEID_BTRFS_WITHOUT_PARENT;
 
-	fid->objectid = btrfs_ino(inode);
-	fid->root_objectid = BTRFS_I(inode)->root->objectid;
+	fid->objectid = btrfs_ino(BTRFS_I(inode));
+	fid->root_objectid = btrfs_root_id(BTRFS_I(inode)->root);
 	fid->gen = inode->i_generation;
 
 	if (parent) {
 		u64 parent_root_id;
 
-		fid->parent_objectid = BTRFS_I(parent)->location.objectid;
+		fid->parent_objectid = btrfs_ino(BTRFS_I(parent));
 		fid->parent_gen = parent->i_generation;
-		parent_root_id = BTRFS_I(parent)->root->objectid;
+		parent_root_id = btrfs_root_id(BTRFS_I(parent)->root);
 
 		if (parent_root_id != fid->root_objectid) {
+			if (*max_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT)
+				return FILEID_INVALID;
 			fid->parent_root_objectid = parent_root_id;
 			len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
 			type = FILEID_BTRFS_WITH_PARENT_ROOT;
@@ -56,53 +64,43 @@ 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)
+/*
+ * Read dentry of inode with @objectid from filesystem root @root_objectid.
+ *
+ * @sb:             the filesystem super block
+ * @objectid:       inode objectid
+ * @root_objectid:  object id of the subvolume root where to look up the inode
+ * @generation:     optional, if not zero, verify that the found inode
+ *                  generation matches
+ *
+ * Return dentry alias for the inode, otherwise an error. In case the
+ * generation does not match return ESTALE.
+ */
+struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
+				u64 root_objectid, u64 generation)
 {
 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 	struct btrfs_root *root;
-	struct inode *inode;
-	struct btrfs_key key;
-	int index;
-	int err = 0;
+	struct btrfs_inode *inode;
 
 	if (objectid < BTRFS_FIRST_FREE_OBJECTID)
 		return ERR_PTR(-ESTALE);
 
-	key.objectid = root_objectid;
-	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
-	key.offset = (u64)-1;
-
-	index = srcu_read_lock(&fs_info->subvol_srcu);
-
-	root = btrfs_read_fs_root_no_name(fs_info, &key);
-	if (IS_ERR(root)) {
-		err = PTR_ERR(root);
-		goto fail;
-	}
+	root = btrfs_get_fs_root(fs_info, root_objectid, true);
+	if (IS_ERR(root))
+		return ERR_CAST(root);
 
-	key.objectid = objectid;
-	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
-	key.offset = 0;
+	inode = btrfs_iget(objectid, root);
+	btrfs_put_root(root);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
 
-	inode = btrfs_iget(sb, &key, root, NULL);
-	if (IS_ERR(inode)) {
-		err = PTR_ERR(inode);
-		goto fail;
-	}
-
-	srcu_read_unlock(&fs_info->subvol_srcu, index);
-
-	if (check_generation && generation != inode->i_generation) {
-		iput(inode);
+	if (generation != 0 && generation != inode->vfs_inode.i_generation) {
+		iput(&inode->vfs_inode);
 		return ERR_PTR(-ESTALE);
 	}
 
-	return d_obtain_alias(inode);
-fail:
-	srcu_read_unlock(&fs_info->subvol_srcu, index);
-	return ERR_PTR(err);
+	return d_obtain_alias(&inode->vfs_inode);
 }
 
 static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
@@ -113,11 +111,11 @@ static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
 	u32 generation;
 
 	if (fh_type == FILEID_BTRFS_WITH_PARENT) {
-		if (fh_len !=  BTRFS_FID_SIZE_CONNECTABLE)
+		if (fh_len <  BTRFS_FID_SIZE_CONNECTABLE)
 			return NULL;
 		root_objectid = fid->root_objectid;
 	} else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
-		if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT)
+		if (fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT)
 			return NULL;
 		root_objectid = fid->parent_root_objectid;
 	} else
@@ -126,7 +124,7 @@ static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
 	objectid = fid->parent_objectid;
 	generation = fid->parent_gen;
 
-	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
+	return btrfs_get_dentry(sb, objectid, root_objectid, generation);
 }
 
 static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
@@ -137,24 +135,26 @@ static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
 	u32 generation;
 
 	if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
-	     fh_len != BTRFS_FID_SIZE_CONNECTABLE) &&
+	     fh_len < BTRFS_FID_SIZE_CONNECTABLE) &&
 	    (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
-	     fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
+	     fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
 	    (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
-	     fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE))
+	     fh_len < BTRFS_FID_SIZE_NON_CONNECTABLE))
 		return NULL;
 
 	objectid = fid->objectid;
 	root_objectid = fid->root_objectid;
 	generation = fid->gen;
 
-	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
+	return btrfs_get_dentry(sb, objectid, root_objectid, generation);
 }
 
-static struct dentry *btrfs_get_parent(struct dentry *child)
+struct dentry *btrfs_get_parent(struct dentry *child)
 {
-	struct inode *dir = child->d_inode;
-	struct btrfs_root *root = BTRFS_I(dir)->root;
+	struct btrfs_inode *dir = BTRFS_I(d_inode(child));
+	struct btrfs_inode *inode;
+	struct btrfs_root *root = dir->root;
+	struct btrfs_fs_info *fs_info = root->fs_info;
 	struct btrfs_path *path;
 	struct extent_buffer *leaf;
 	struct btrfs_root_ref *ref;
@@ -167,10 +167,10 @@ static struct dentry *btrfs_get_parent(struct dentry *child)
 		return ERR_PTR(-ENOMEM);
 
 	if (btrfs_ino(dir) == BTRFS_FIRST_FREE_OBJECTID) {
-		key.objectid = root->root_key.objectid;
+		key.objectid = btrfs_root_id(root);
 		key.type = BTRFS_ROOT_BACKREF_KEY;
 		key.offset = (u64)-1;
-		root = root->fs_info->tree_root;
+		root = fs_info->tree_root;
 	} else {
 		key.objectid = btrfs_ino(dir);
 		key.type = BTRFS_INODE_REF_KEY;
@@ -180,8 +180,15 @@ static struct dentry *btrfs_get_parent(struct dentry *child)
 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 	if (ret < 0)
 		goto fail;
+	if (unlikely(ret == 0)) {
+		/*
+		 * Key with offset of -1 found, there would have to exist an
+		 * inode with such number or a root with such id.
+		 */
+		ret = -EUCLEAN;
+		goto fail;
+	}
 
-	BUG_ON(ret == 0); /* Key with offset of -1 found */
 	if (path->slots[0] == 0) {
 		ret = -ENOENT;
 		goto fail;
@@ -206,13 +213,15 @@ static struct dentry *btrfs_get_parent(struct dentry *child)
 	btrfs_free_path(path);
 
 	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
-		return btrfs_get_dentry(root->fs_info->sb, key.objectid,
-					found_key.offset, 0, 0);
+		return btrfs_get_dentry(fs_info->sb, key.objectid,
+					found_key.offset, 0);
 	}
 
-	key.type = BTRFS_INODE_ITEM_KEY;
-	key.offset = 0;
-	return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
+	inode = btrfs_iget(key.objectid, root);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+
+	return d_obtain_alias(&inode->vfs_inode);
 fail:
 	btrfs_free_path(path);
 	return ERR_PTR(ret);
@@ -221,10 +230,11 @@ fail:
 static int btrfs_get_name(struct dentry *parent, char *name,
 			  struct dentry *child)
 {
-	struct inode *inode = child->d_inode;
-	struct inode *dir = parent->d_inode;
-	struct btrfs_path *path;
-	struct btrfs_root *root = BTRFS_I(dir)->root;
+	struct btrfs_inode *inode = BTRFS_I(d_inode(child));
+	struct btrfs_inode *dir = BTRFS_I(d_inode(parent));
+	struct btrfs_root *root = dir->root;
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	BTRFS_PATH_AUTO_FREE(path);
 	struct btrfs_inode_ref *iref;
 	struct btrfs_root_ref *rref;
 	struct extent_buffer *leaf;
@@ -234,10 +244,7 @@ static int btrfs_get_name(struct dentry *parent, char *name,
 	int ret;
 	u64 ino;
 
-	if (!dir || !inode)
-		return -EINVAL;
-
-	if (!S_ISDIR(dir->i_mode))
+	if (!S_ISDIR(dir->vfs_inode.i_mode))
 		return -EINVAL;
 
 	ino = btrfs_ino(inode);
@@ -245,30 +252,26 @@ static int btrfs_get_name(struct dentry *parent, char *name,
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
-	path->leave_spinning = 1;
 
 	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
-		key.objectid = BTRFS_I(inode)->root->root_key.objectid;
+		key.objectid = btrfs_root_id(inode->root);
 		key.type = BTRFS_ROOT_BACKREF_KEY;
 		key.offset = (u64)-1;
-		root = root->fs_info->tree_root;
+		root = fs_info->tree_root;
 	} else {
 		key.objectid = ino;
-		key.offset = btrfs_ino(dir);
 		key.type = BTRFS_INODE_REF_KEY;
+		key.offset = btrfs_ino(dir);
 	}
 
 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 	if (ret < 0) {
-		btrfs_free_path(path);
 		return ret;
 	} else if (ret > 0) {
-		if (ino == BTRFS_FIRST_FREE_OBJECTID) {
+		if (ino == BTRFS_FIRST_FREE_OBJECTID)
 			path->slots[0]--;
-		} else {
-			btrfs_free_path(path);
+		else
 			return -ENOENT;
-		}
 	}
 	leaf = path->nodes[0];
 
@@ -285,7 +288,6 @@ static int btrfs_get_name(struct dentry *parent, char *name,
 	}
 
 	read_extent_buffer(leaf, name, name_ptr, name_len);
-	btrfs_free_path(path);
 
 	/*
 	 * have to add the null termination to make sure that reconnect_path