[RFC PATCH] cifs: remove superfluous inode_lock in cifs_{strict_}fsync

[Jeff Layton <jlayton@kernel.org>]

Originally, filemap_write_and_wait took the i_mutex internally, but
commit 02c24a82187d pushed the mutex acquisition into the individual
fsync routines, leaving it up to the subsystem maintainers to remove
it if it wasn't needed.

For cifs, I see no reason to take the inode_lock here. All of the
operations inside that lock are protected in other ways.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/cifs/file.c | 5 -----
 1 file changed, 5 deletions(-)

Steve, would you or someone else be able to test this?

I'm proposing a similar patch for kcephfs. I don't have an appropriate
test rig at the moment, and I was hoping someone more involved with
cifs.ko development these days may be able to do so.

Thanks,
Jeff

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 89006e044973..c4b84fd423c3 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2424,7 +2424,6 @@ int cifs_strict_fsync(struct file *file, loff_t start, loff_t end,
 	rc = file_write_and_wait_range(file, start, end);
 	if (rc)
 		return rc;
-	inode_lock(inode);
 
 	xid = get_xid();
 
@@ -2449,7 +2448,6 @@ int cifs_strict_fsync(struct file *file, loff_t start, loff_t end,
 	}
 
 	free_xid(xid);
-	inode_unlock(inode);
 	return rc;
 }
 
@@ -2461,12 +2459,10 @@ int cifs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 	struct TCP_Server_Info *server;
 	struct cifsFileInfo *smbfile = file->private_data;
 	struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
-	struct inode *inode = file->f_mapping->host;
 
 	rc = file_write_and_wait_range(file, start, end);
 	if (rc)
 		return rc;
-	inode_lock(inode);
 
 	xid = get_xid();
 
@@ -2483,7 +2479,6 @@ int cifs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 	}
 
 	free_xid(xid);
-	inode_unlock(inode);
 	return rc;
 }
 
-- 
2.20.1