[RFC PATCH 04/18] ext4: add a hole extent entry in cache after punch

[Zhang Yi <yi.zhang@huaweicloud.com>]

From: Zhang Yi <yi.zhang@huawei.com>

In order to cache hole extents in the extent status tree and keep the
hole continuity as much as possible, add a hole entry to the cache after
punching a hole. It can reduce the 'hole' in some continuous hole extent
entries.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
 fs/ext4/ext4.h    | 3 +++
 fs/ext4/extents.c | 5 ++---
 fs/ext4/inode.c   | 2 ++
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 9418359b1d9d..c2ca28c6ec38 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3681,6 +3681,9 @@ extern int ext4_convert_unwritten_io_end_vec(handle_t *handle,
 					     ext4_io_end_t *io_end);
 extern int ext4_map_blocks(handle_t *handle, struct inode *inode,
 			   struct ext4_map_blocks *map, int flags);
+extern void ext4_ext_put_gap_in_cache(struct inode *inode,
+				      ext4_lblk_t hole_start,
+				      ext4_lblk_t hole_len);
 extern int ext4_ext_calc_credits_for_single_extent(struct inode *inode,
 						   int num,
 						   struct ext4_ext_path *path);
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 202c76996b62..52bad225e3c8 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2275,9 +2275,8 @@ static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
  * calculate boundaries of the gap that the requested block fits into
  * and cache this gap
  */
-static void
-ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
-			  ext4_lblk_t hole_len)
+void ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
+			       ext4_lblk_t hole_len)
 {
 	struct extent_status es;
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 94e7b8500878..3908ce7f6fb8 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4034,6 +4034,8 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
 			ret = ext4_ind_remove_space(handle, inode, first_block,
 						    stop_block);
 
+		ext4_ext_put_gap_in_cache(inode, first_block,
+					  stop_block - first_block);
 		up_write(&EXT4_I(inode)->i_data_sem);
 	}
 	ext4_fc_track_range(handle, inode, first_block, stop_block);
-- 
2.39.2