ext4: add ext4_get_block_dax()
DAX wants different semantics from any currently-existing ext4 get_block
callback. Unlike ext4_get_block_write(), it needs to honour the
'create' flag, and unlike ext4_get_block(), it needs to be able to
return unwritten extents. So introduce a new ext4_get_block_dax() which
has those semantics.
We could also change ext4_get_block_write() to honour the 'create' flag,
but that might have consequences on other users that I do not currently
understand.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 5ebcc76..612fbcf 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3021,6 +3021,17 @@
EXT4_GET_BLOCKS_NO_LOCK);
}
+int ext4_get_block_dax(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create)
+{
+ int flags = EXT4_GET_BLOCKS_PRE_IO | EXT4_GET_BLOCKS_UNWRIT_EXT;
+ if (create)
+ flags |= EXT4_GET_BLOCKS_CREATE;
+ ext4_debug("ext4_get_block_dax: inode %lu, create flag %d\n",
+ inode->i_ino, create);
+ return _ext4_get_block(inode, iblock, bh_result, flags);
+}
+
static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
ssize_t size, void *private)
{