vfs: Move mark_inode_dirty() from under page lock in generic_write_end()
There's no need to call mark_inode_dirty() under page lock in
generic_write_end(). It unnecessarily makes hold time of page lock longer
and more importantly it forces locking order of page lock and transaction
start for journaling filesystems.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/buffer.c b/fs/buffer.c
index 0f51c0f..f4b0332 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2061,6 +2061,7 @@
struct page *page, void *fsdata)
{
struct inode *inode = mapping->host;
+ int i_size_changed = 0;
copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
@@ -2073,12 +2074,21 @@
*/
if (pos+copied > inode->i_size) {
i_size_write(inode, pos+copied);
- mark_inode_dirty(inode);
+ i_size_changed = 1;
}
unlock_page(page);
page_cache_release(page);
+ /*
+ * Don't mark the inode dirty under page lock. First, it unnecessarily
+ * makes the holding time of page lock longer. Second, it forces lock
+ * ordering of page lock and transaction start for journaling
+ * filesystems.
+ */
+ if (i_size_changed)
+ mark_inode_dirty(inode);
+
return copied;
}
EXPORT_SYMBOL(generic_write_end);