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Commit fa33915c authored by Ryusuke Konishi's avatar Ryusuke Konishi Committed by Linus Torvalds
Browse files

nilfs2: add helper to find existent block on metadata file 



Add a new metadata file function, nilfs_mdt_find_block(), which finds
an existent block on a metadata file in a given range of blocks.  This
function skips continuous hole blocks efficiently by using
nilfs_bmap_seek_key().

Signed-off-by: default avatarRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5b20384f

fs/nilfs2/mdt.c

+54 −0
Original line number Diff line number Diff line
@@ -260,6 +260,60 @@ int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create, 
	return ret;

}



/**

 * nilfs_mdt_find_block - find and get a buffer on meta data file.

 * @inode: inode of the meta data file

 * @start: start block offset (inclusive)

 * @end: end block offset (inclusive)

 * @blkoff: block offset

 * @out_bh: place to store a pointer to buffer_head struct

 *

 * nilfs_mdt_find_block() looks up an existing block in range of

 * [@start, @end] and stores pointer to a buffer head of the block to

 * @out_bh, and block offset to @blkoff, respectively.  @out_bh and

 * @blkoff are substituted only when zero is returned.

 *

 * Return Value: On success, it returns 0. On error, the following negative

 * error code is returned.

 *

 * %-ENOMEM - Insufficient memory available.

 *

 * %-EIO - I/O error

 *

 * %-ENOENT - no block was found in the range

 */

int nilfs_mdt_find_block(struct inode *inode, unsigned long start,

			 unsigned long end, unsigned long *blkoff,

			 struct buffer_head **out_bh)

{

	__u64 next;

	int ret;



	if (unlikely(start > end))

		return -ENOENT;



	ret = nilfs_mdt_read_block(inode, start, true, out_bh);

	if (!ret) {

		*blkoff = start;

		goto out;

	}

	if (unlikely(ret != -ENOENT || start == ULONG_MAX))

		goto out;



	ret = nilfs_bmap_seek_key(NILFS_I(inode)->i_bmap, start + 1, &next);

	if (!ret) {

		if (next <= end) {

			ret = nilfs_mdt_read_block(inode, next, true, out_bh);

			if (!ret)

				*blkoff = next;

		} else {

			ret = -ENOENT;

		}

	}

out:

	return ret;

}



/**

 * nilfs_mdt_delete_block - make a hole on the meta data file.

 * @inode: inode of the meta data file

fs/nilfs2/mdt.h

+3 −0
Original line number Diff line number Diff line
@@ -78,6 +78,9 @@ int nilfs_mdt_get_block(struct inode *, unsigned long, int, 
			void (*init_block)(struct inode *,

					   struct buffer_head *, void *),

			struct buffer_head **);

int nilfs_mdt_find_block(struct inode *inode, unsigned long start,

			 unsigned long end, unsigned long *blkoff,

			 struct buffer_head **out_bh);

int nilfs_mdt_delete_block(struct inode *, unsigned long);

int nilfs_mdt_forget_block(struct inode *, unsigned long);

int nilfs_mdt_mark_block_dirty(struct inode *, unsigned long);