Commit ab0fff03 authored by Arne Jansen's avatar Arne Jansen
Browse files

btrfs: add READAHEAD extent buffer flag 



Add a READAHEAD extent buffer flag.
Add a function to trigger a read with this flag set.

Changes v2:
 - use extent buffer flags instead of extent state flags

Changes v5:
 - adapt to changed read_extent_buffer_pages interface
 - don't return eb from reada_tree_block_flagged if it has CORRUPT flag set

Signed-off-by: default avatarArne Jansen <sensille@gmx.net>
parent bb82ab88

fs/btrfs/disk-io.c

+32 −0
Original line number Diff line number Diff line
@@ -980,6 +980,38 @@ int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize, 
	return ret;

}



int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr, u32 blocksize,

			 int mirror_num, struct extent_buffer **eb)

{

	struct extent_buffer *buf = NULL;

	struct inode *btree_inode = root->fs_info->btree_inode;

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

	int ret;



	buf = btrfs_find_create_tree_block(root, bytenr, blocksize);

	if (!buf)

		return 0;



	set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);



	ret = read_extent_buffer_pages(io_tree, buf, 0, WAIT_PAGE_LOCK,

				       btree_get_extent, mirror_num);

	if (ret) {

		free_extent_buffer(buf);

		return ret;

	}



	if (test_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags)) {

		free_extent_buffer(buf);

		return -EIO;

	} else if (extent_buffer_uptodate(io_tree, buf, NULL)) {

		*eb = buf;

	} else {

		free_extent_buffer(buf);

	}

	return 0;

}



struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,

					    u64 bytenr, u32 blocksize)

{

fs/btrfs/disk-io.h

+2 −0
Original line number Diff line number Diff line
@@ -40,6 +40,8 @@ struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr, 
				      u32 blocksize, u64 parent_transid);

int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,

			 u64 parent_transid);

int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr, u32 blocksize,

			 int mirror_num, struct extent_buffer **eb);

struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,

						   u64 bytenr, u32 blocksize);

int clean_tree_block(struct btrfs_trans_handle *trans,

fs/btrfs/extent_io.h

+1 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 
#define EXTENT_BUFFER_BLOCKING 1

#define EXTENT_BUFFER_DIRTY 2

#define EXTENT_BUFFER_CORRUPT 3

#define EXTENT_BUFFER_READAHEAD 4	/* this got triggered by readahead */



/* these are flags for extent_clear_unlock_delalloc */

#define EXTENT_CLEAR_UNLOCK_PAGE 0x1

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