Commit c81ea11e authored by Dave Chinner's avatar Dave Chinner Committed by Darrick J. Wong
Browse files

xfs: xfs_buf_item_size_segment() needs to pass segment offset 



Otherwise it doesn't correctly calculate the number of vectors
in a logged buffer that has a contiguous map that gets split into
multiple regions because the range spans discontigous memory.

Probably never been hit in practice - we don't log contiguous ranges
on unmapped buffers (inode clusters).

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
parent accc661b

fs/xfs/xfs_buf_item.c

+19 −19
Original line number Diff line number Diff line
@@ -55,6 +55,18 @@ xfs_buf_log_format_size( 
			(blfp->blf_map_size * sizeof(blfp->blf_data_map[0]));

}



static inline bool

xfs_buf_item_straddle(

	struct xfs_buf		*bp,

	uint			offset,

	int			next_bit,

	int			last_bit)

{

	return xfs_buf_offset(bp, offset + (next_bit << XFS_BLF_SHIFT)) !=

		(xfs_buf_offset(bp, offset + (last_bit << XFS_BLF_SHIFT)) +

		 XFS_BLF_CHUNK);

}



/*

 * This returns the number of log iovecs needed to log the

 * given buf log item.
@@ -69,6 +81,7 @@ STATIC void 
xfs_buf_item_size_segment(

	struct xfs_buf_log_item		*bip,

	struct xfs_buf_log_format	*blfp,

	uint				offset,

	int				*nvecs,

	int				*nbytes)

{
@@ -103,12 +116,8 @@ xfs_buf_item_size_segment( 
		 */

		if (next_bit == -1) {

			break;

		} else if (next_bit != last_bit + 1) {

			last_bit = next_bit;

			(*nvecs)++;

		} else if (xfs_buf_offset(bp, next_bit * XFS_BLF_CHUNK) !=

			   (xfs_buf_offset(bp, last_bit * XFS_BLF_CHUNK) +

			    XFS_BLF_CHUNK)) {

		} else if (next_bit != last_bit + 1 ||

		           xfs_buf_item_straddle(bp, offset, next_bit, last_bit)) {

			last_bit = next_bit;

			(*nvecs)++;

		} else {
@@ -142,8 +151,10 @@ xfs_buf_item_size( 
	int			*nbytes)

{

	struct xfs_buf_log_item	*bip = BUF_ITEM(lip);

	struct xfs_buf		*bp = bip->bli_buf;

	int			i;

	int			bytes;

	uint			offset = 0;



	ASSERT(atomic_read(&bip->bli_refcount) > 0);

	if (bip->bli_flags & XFS_BLI_STALE) {
@@ -185,8 +196,9 @@ xfs_buf_item_size( 
	 */

	bytes = 0;

	for (i = 0; i < bip->bli_format_count; i++) {

		xfs_buf_item_size_segment(bip, &bip->bli_formats[i],

		xfs_buf_item_size_segment(bip, &bip->bli_formats[i], offset,

					  nvecs, &bytes);

		offset += BBTOB(bp->b_maps[i].bm_len);

	}



	/*
@@ -213,18 +225,6 @@ xfs_buf_item_copy_iovec( 
			nbits * XFS_BLF_CHUNK);

}



static inline bool

xfs_buf_item_straddle(

	struct xfs_buf		*bp,

	uint			offset,

	int			next_bit,

	int			last_bit)

{

	return xfs_buf_offset(bp, offset + (next_bit << XFS_BLF_SHIFT)) !=

		(xfs_buf_offset(bp, offset + (last_bit << XFS_BLF_SHIFT)) +

		 XFS_BLF_CHUNK);

}



static void

xfs_buf_item_format_segment(

	struct xfs_buf_log_item	*bip,