Commit 9e2aff90 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by David Sterba
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btrfs: stop using lock_extent in btrfs_buffer_uptodate 



The only other place that locks extents on the btree inode is
read_extent_buffer_subpage while reading in the partial page for a
buffer.  This means locking the extent in btrfs_buffer_uptodate does not
synchronize with anything on non-subpage file systems, and on subpage
file systems it only waits for a parallel read(-ahead) to finish,
which seems to be counter to what the callers actually expect.

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent f3d315eb

fs/btrfs/disk-io.c

+2 −10
Original line number Diff line number Diff line
@@ -112,11 +112,6 @@ static void csum_tree_block(struct extent_buffer *buf, u8 *result) 
 */

int btrfs_buffer_uptodate(struct extent_buffer *eb, u64 parent_transid, int atomic)

{

	struct inode *btree_inode = eb->pages[0]->mapping->host;

	struct extent_io_tree *io_tree = &BTRFS_I(btree_inode)->io_tree;

	struct extent_state *cached_state = NULL;

	int ret = 1;



	if (!extent_buffer_uptodate(eb))

		return 0;
@@ -126,7 +121,6 @@ int btrfs_buffer_uptodate(struct extent_buffer *eb, u64 parent_transid, int atom 
	if (atomic)

		return -EAGAIN;



	lock_extent(io_tree, eb->start, eb->start + eb->len - 1, &cached_state);

	if (!extent_buffer_uptodate(eb) ||

	    btrfs_header_generation(eb) != parent_transid) {

		btrfs_err_rl(eb->fs_info,
@@ -134,11 +128,9 @@ int btrfs_buffer_uptodate(struct extent_buffer *eb, u64 parent_transid, int atom 
			eb->start, eb->read_mirror,

			parent_transid, btrfs_header_generation(eb));

		clear_extent_buffer_uptodate(eb);

		ret = 0;

		return 0;

	}

	unlock_extent(io_tree, eb->start, eb->start + eb->len - 1,

		      &cached_state);

	return ret;

	return 1;

}



static bool btrfs_supported_super_csum(u16 csum_type)