Re: [syzbot] [hfs?] possible deadlock in hfsplus_file_extend (2)

[Edward Adam Davis]

AA lock, move extents_lock out of the hfsplus_file_extend.

#syz test

diff --git a/fs/hfsplus/btree.c b/fs/hfsplus/btree.c
index 9e1732a2b92a..ec6e9bdfe7b4 100644
--- a/fs/hfsplus/btree.c
+++ b/fs/hfsplus/btree.c
@@ -355,7 +355,9 @@ int hfs_bmap_reserve(struct hfs_btree *tree, int rsvd_nodes)
 		return 0;
 
 	while (tree->free_nodes < rsvd_nodes) {
+		mutex_lock(&hip->extents_lock);
 		res = hfsplus_file_extend(inode, hfs_bnode_need_zeroout(tree));
+		mutex_unlock(&hip->extents_lock);
 		if (res)
 			return res;
 		hip->phys_size = inode->i_size =
diff --git a/fs/hfsplus/extents.c b/fs/hfsplus/extents.c
index a6d61685ae79..966252d129bc 100644
--- a/fs/hfsplus/extents.c
+++ b/fs/hfsplus/extents.c
@@ -242,7 +242,9 @@ int hfsplus_get_block(struct inode *inode, sector_t iblock,
 		if (iblock > hip->fs_blocks)
 			return -EIO;
 		if (ablock >= hip->alloc_blocks) {
+			mutex_lock(&hip->extents_lock);
 			res = hfsplus_file_extend(inode, false);
+			mutex_unlock(&hip->extents_lock);
 			if (res)
 				return res;
 		}
@@ -455,7 +457,6 @@ int hfsplus_file_extend(struct inode *inode, bool zeroout)
 		return -ENOSPC;
 	}
 
-	mutex_lock(&hip->extents_lock);
 	if (hip->alloc_blocks == hip->first_blocks)
 		goal = hfsplus_ext_lastblock(hip->first_extents);
 	else {
@@ -516,11 +517,9 @@ int hfsplus_file_extend(struct inode *inode, bool zeroout)
 out:
 	if (!res) {
 		hip->alloc_blocks += len;
-		mutex_unlock(&hip->extents_lock);
 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
 		return 0;
 	}
-	mutex_unlock(&hip->extents_lock);
 	return res;
 
 insert_extent:
diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
index 9a1a93e3888b..a589130e42ea 100644
--- a/fs/hfsplus/xattr.c
+++ b/fs/hfsplus/xattr.c
@@ -191,7 +191,9 @@ static int hfsplus_create_attributes_file(struct super_block *sb)
 	}
 
 	while (hip->alloc_blocks < hip->clump_blocks) {
+		mutex_unlock(&hip->extents_lock);
 		err = hfsplus_file_extend(attr_file, false);
+		mutex_unlock(&hip->extents_lock);
 		if (unlikely(err)) {
 			pr_err("failed to extend attributes file\n");
 			goto end_attr_file_creation;