[PATCH v4 01/23] ext4: simplify size updating in ext4_setattr()

[Zhang Yi]

From: Zhang Yi <yi.zhang@xxxxxxxxxx>

The logic for updating the file size in ext4_setattr() is currently
somewhat messy. By directly entering the error-handling path after
failing to add an orphan inode, the unnecessary recovery process
involving old_disksize and the file size can be avoided.

Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
---
 fs/ext4/inode.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c2c2d6ac7f3d..0751dc55e94f 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5953,7 +5953,6 @@ int ext4_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	if (attr->ia_valid & ATTR_SIZE) {
 		handle_t *handle;
 		loff_t oldsize = inode->i_size;
-		loff_t old_disksize;
 		int shrink = (attr->ia_size < inode->i_size);
 
 		if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
@@ -6037,6 +6036,8 @@ int ext4_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 			if (ext4_handle_valid(handle) && shrink) {
 				error = ext4_orphan_add(handle, inode);
 				orphan = 1;
+				if (error)
+					goto out_handle;
 			}
 
 			if (shrink)
@@ -6052,23 +6053,18 @@ int ext4_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 					(attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
 					inode->i_sb->s_blocksize_bits);
 
-			down_write(&EXT4_I(inode)->i_data_sem);
-			old_disksize = EXT4_I(inode)->i_disksize;
-			EXT4_I(inode)->i_disksize = attr->ia_size;
-
 			/*
 			 * We have to update i_size under i_data_sem together
 			 * with i_disksize to avoid races with writeback code
-			 * running ext4_wb_update_i_disksize().
+			 * updating disksize in mpage_map_and_submit_extent().
 			 */
-			if (!error)
-				i_size_write(inode, attr->ia_size);
-			else
-				EXT4_I(inode)->i_disksize = old_disksize;
+			down_write(&EXT4_I(inode)->i_data_sem);
+			i_size_write(inode, attr->ia_size);
+			EXT4_I(inode)->i_disksize = attr->ia_size;
 			up_write(&EXT4_I(inode)->i_data_sem);
-			rc = ext4_mark_inode_dirty(handle, inode);
-			if (!error)
-				error = rc;
+
+			error = ext4_mark_inode_dirty(handle, inode);
+out_handle:
 			ext4_journal_stop(handle);
 			if (error)
 				goto out_mmap_sem;
-- 
2.52.0