ext4: Convert truncate_mutex to read write semaphore.

We are currently taking the truncate_mutex for every read. This would have
performance impact on large CPU configuration. Convert the lock to read write
semaphore and take read lock when we are trying to read the file.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

1 files changed, 4 insertions, 21 deletions

diff --git a/include/linux/ext4_fs.h b/include/linux/ext4_fs.h
index 583049c1d36..300cc5a5adb 100644
--- a/include/linux/ext4_fs.h
+++ b/include/linux/ext4_fs.h
@@ -1107,27 +1107,10 @@ extern void ext4_ext_init(struct super_block *);
 extern void ext4_ext_release(struct super_block *);
 extern long ext4_fallocate(struct inode *inode, int mode, loff_t offset,
 			  loff_t len);
-static inline int
-ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
-			unsigned long max_blocks, struct buffer_head *bh,
-			int create, int extend_disksize)
-{
-	int retval;
-	mutex_lock(&EXT4_I(inode)->truncate_mutex);
-	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
-		retval = ext4_ext_get_blocks(handle, inode,
-						(ext4_lblk_t)block, max_blocks,
-						bh, create, extend_disksize);
-	} else {
-		retval = ext4_get_blocks_handle(handle, inode,
-						(ext4_lblk_t)block, max_blocks,
-						bh, create, extend_disksize);
-	}
-	mutex_unlock(&EXT4_I(inode)->truncate_mutex);
-	return retval;
-}
-
-
+extern int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode,
+			sector_t block, unsigned long max_blocks,
+			struct buffer_head *bh, int create,
+			int extend_disksize);
 #endif	/* __KERNEL__ */
 
 #endif	/* _LINUX_EXT4_FS_H */