[PATCH 4/5] f2fs: compress: fix to cover {reserve,release}_compress_blocks() w/ cp_rwsem lock

[Chao Yu]

It needs to cover {reserve,release}_compress_blocks() w/ cp_rwsem lock
to avoid racing with checkpoint, otherwise, filesystem metadata including
blkaddr in dnode, inode fields and .total_valid_block_count may be
corrupted after SPO case.

Fixes: ef8d563f184e ("f2fs: introduce F2FS_IOC_RELEASE_COMPRESS_BLOCKS")
Fixes: c75488fb4d82 ("f2fs: introduce F2FS_IOC_RESERVE_COMPRESS_BLOCKS")
Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
---
 fs/f2fs/file.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index e77e958a9f92..3f0db351e976 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -3570,9 +3570,12 @@ static int f2fs_release_compress_blocks(struct file *filp, unsigned long arg)
 		struct dnode_of_data dn;
 		pgoff_t end_offset, count;
 
+		f2fs_lock_op(sbi);
+
 		set_new_dnode(&dn, inode, NULL, NULL, 0);
 		ret = f2fs_get_dnode_of_data(&dn, page_idx, LOOKUP_NODE);
 		if (ret) {
+			f2fs_unlock_op(sbi);
 			if (ret == -ENOENT) {
 				page_idx = f2fs_get_next_page_offset(&dn,
 								page_idx);
@@ -3590,6 +3593,8 @@ static int f2fs_release_compress_blocks(struct file *filp, unsigned long arg)
 
 		f2fs_put_dnode(&dn);
 
+		f2fs_unlock_op(sbi);
+
 		if (ret < 0)
 			break;
 
@@ -3742,9 +3747,12 @@ static int f2fs_reserve_compress_blocks(struct file *filp, unsigned long arg)
 		struct dnode_of_data dn;
 		pgoff_t end_offset, count;
 
+		f2fs_lock_op(sbi);
+
 		set_new_dnode(&dn, inode, NULL, NULL, 0);
 		ret = f2fs_get_dnode_of_data(&dn, page_idx, LOOKUP_NODE);
 		if (ret) {
+			f2fs_unlock_op(sbi);
 			if (ret == -ENOENT) {
 				page_idx = f2fs_get_next_page_offset(&dn,
 								page_idx);
@@ -3762,6 +3770,8 @@ static int f2fs_reserve_compress_blocks(struct file *filp, unsigned long arg)
 
 		f2fs_put_dnode(&dn);
 
+		f2fs_unlock_op(sbi);
+
 		if (ret < 0)
 			break;
 
-- 
2.40.1