vfs: Move mark_inode_dirty() from under page lock in generic_write_end() From: Jan Kara 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 Signed-off-by: Aneesh Kumar K.V Signed-off-by: "Theodore Ts'o" --- fs/buffer.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) Index: linux-2.6.26-rc9/fs/buffer.c =================================================================== --- linux-2.6.26-rc9.orig/fs/buffer.c 2008-07-11 16:04:28.000000000 -0700 +++ linux-2.6.26-rc9/fs/buffer.c 2008-07-11 16:05:08.000000000 -0700 @@ -2061,6 +2061,7 @@ int generic_write_end(struct file *file, 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 @@ int generic_write_end(struct file *file, */ 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);