Commit 4c7f65ae authored by Dave Chinner's avatar Dave Chinner Committed by Darrick J. Wong
Browse files

xfs: rename buffer cache index variable b_bn 



To stop external users from using b_bn as the disk address of the
buffer, rename it to b_rhash_key to indicate that it is the buffer
cache index, not the block number of the buffer. Code that needs the
disk address should use xfs_buf_daddr() to obtain it.

Do the rename and clean up any of the remaining internal b_bn users.
Also clean up any remaining b_bn cruft that is now unused.

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
parent 9343ee76

fs/xfs/xfs_buf.c

+11 −8
Original line number Diff line number Diff line
@@ -251,7 +251,7 @@ _xfs_buf_alloc( 
		return error;

	}



	bp->b_bn = map[0].bm_bn;

	bp->b_rhash_key = map[0].bm_bn;

	bp->b_length = 0;

	for (i = 0; i < nmaps; i++) {

		bp->b_maps[i].bm_bn = map[i].bm_bn;
@@ -459,7 +459,7 @@ _xfs_buf_obj_cmp( 
	 */

	BUILD_BUG_ON(offsetof(struct xfs_buf_map, bm_bn) != 0);



	if (bp->b_bn != map->bm_bn)

	if (bp->b_rhash_key != map->bm_bn)

		return 1;



	if (unlikely(bp->b_length != map->bm_len)) {
@@ -481,7 +481,7 @@ static const struct rhashtable_params xfs_buf_hash_params = { 
	.min_size		= 32,	/* empty AGs have minimal footprint */

	.nelem_hint		= 16,

	.key_len		= sizeof(xfs_daddr_t),

	.key_offset		= offsetof(struct xfs_buf, b_bn),

	.key_offset		= offsetof(struct xfs_buf, b_rhash_key),

	.head_offset		= offsetof(struct xfs_buf, b_rhash_head),

	.automatic_shrinking	= true,

	.obj_cmpfn		= _xfs_buf_obj_cmp,
@@ -853,7 +853,9 @@ xfs_buf_readahead_map( 


/*

 * Read an uncached buffer from disk. Allocates and returns a locked

 * buffer containing the disk contents or nothing.

 * buffer containing the disk contents or nothing. Uncached buffers always have

 * a cache index of XFS_BUF_DADDR_NULL so we can easily determine if the buffer

 * is cached or uncached during fault diagnosis.

 */

int

xfs_buf_read_uncached(
@@ -875,7 +877,7 @@ xfs_buf_read_uncached( 


	/* set up the buffer for a read IO */

	ASSERT(bp->b_map_count == 1);

	bp->b_bn = XFS_BUF_DADDR_NULL;  /* always null for uncached buffers */

	bp->b_rhash_key = XFS_BUF_DADDR_NULL;

	bp->b_maps[0].bm_bn = daddr;

	bp->b_flags |= XBF_READ;

	bp->b_ops = ops;
@@ -1513,7 +1515,7 @@ _xfs_buf_ioapply( 
						   SHUTDOWN_CORRUPT_INCORE);

				return;

			}

		} else if (bp->b_bn != XFS_BUF_DADDR_NULL) {

		} else if (bp->b_rhash_key != XFS_BUF_DADDR_NULL) {

			struct xfs_mount *mp = bp->b_mount;



			/*
@@ -1523,7 +1525,8 @@ _xfs_buf_ioapply( 
			if (xfs_has_crc(mp)) {

				xfs_warn(mp,

					"%s: no buf ops on daddr 0x%llx len %d",

					__func__, bp->b_bn, bp->b_length);

					__func__, xfs_buf_daddr(bp),

					bp->b_length);

				xfs_hex_dump(bp->b_addr,

						XFS_CORRUPTION_DUMP_LEN);

				dump_stack();
@@ -1793,7 +1796,7 @@ xfs_buftarg_drain( 
				xfs_buf_alert_ratelimited(bp,

					"XFS: Corruption Alert",

"Corruption Alert: Buffer at daddr 0x%llx had permanent write failures!",

					(long long)bp->b_bn);

					(long long)xfs_buf_daddr(bp));

			}

			xfs_buf_rele(bp);

		}

fs/xfs/xfs_buf.h

+1 −17
Original line number Diff line number Diff line
@@ -134,11 +134,7 @@ struct xfs_buf { 
	 */

	struct rhash_head	b_rhash_head;	/* pag buffer hash node */



	/*

	 * b_bn is the cache index. Do not use directly, use b_maps[0].bm_bn

	 * for the buffer disk address instead.

	 */

	xfs_daddr_t		b_bn;

	xfs_daddr_t		b_rhash_key;	/* buffer cache index */

	int			b_length;	/* size of buffer in BBs */

	atomic_t		b_hold;		/* reference count */

	atomic_t		b_lru_ref;	/* lru reclaim ref count */
@@ -301,18 +297,6 @@ extern int xfs_buf_delwri_pushbuf(struct xfs_buf *, struct list_head *); 
extern int xfs_buf_init(void);

extern void xfs_buf_terminate(void);



/*

 * These macros use the IO block map rather than b_bn. b_bn is now really

 * just for the buffer cache index for cached buffers. As IO does not use b_bn

 * anymore, uncached buffers do not use b_bn at all and hence must modify the IO

 * map directly. Uncached buffers are not allowed to be discontiguous, so this

 * is safe to do.

 *

 * In future, uncached buffers will pass the block number directly to the io

 * request function and hence these macros will go away at that point.

 */

#define XFS_BUF_SET_ADDR(bp, bno)	((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno))



static inline xfs_daddr_t xfs_buf_daddr(struct xfs_buf *bp)

{

	return bp->b_maps[0].bm_bn;