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Commit 889c65b3 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Darrick J. Wong
Browse files

xfs: remove the imap_valid flag 



Simplify the way we check for a valid imap - we know we have a valid
mapping after xfs_map_blocks returned successfully, and we know we can
call xfs_imap_valid on any imap, as it will always fail on a
zero-initialized map.

We can also remove the xfs_imap_valid function and fold it into
xfs_map_blocks now.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent 3345746e

fs/xfs/xfs_aops.c

+38 −51
Original line number Diff line number Diff line
@@ -30,7 +30,6 @@ 
 */

struct xfs_writepage_ctx {

	struct xfs_bmbt_irec    imap;

	bool			imap_valid;

	unsigned int		io_type;

	struct xfs_ioend	*ioend;

	sector_t		last_block;
@@ -370,15 +369,47 @@ xfs_map_blocks( 
	struct xfs_inode	*ip = XFS_I(inode);

	struct xfs_mount	*mp = ip->i_mount;

	ssize_t			count = i_blocksize(inode);

	xfs_fileoff_t		offset_fsb, end_fsb;

	xfs_fileoff_t		offset_fsb = XFS_B_TO_FSBT(mp, offset), end_fsb;

	struct xfs_bmbt_irec	imap;

	int			whichfork = XFS_DATA_FORK;

	struct xfs_iext_cursor	icur;

	bool			imap_valid;

	int			error = 0;



	/*

	 * We have to make sure the cached mapping is within EOF to protect

	 * against eofblocks trimming on file release leaving us with a stale

	 * mapping. Otherwise, a page for a subsequent file extending buffered

	 * write could get picked up by this writeback cycle and written to the

	 * wrong blocks.

	 *

	 * Note that what we really want here is a generic mapping invalidation

	 * mechanism to protect us from arbitrary extent modifying contexts, not

	 * just eofblocks.

	 */

	xfs_trim_extent_eof(&wpc->imap, ip);



	/*

	 * COW fork blocks can overlap data fork blocks even if the blocks

	 * aren't shared.  COW I/O always takes precedent, so we must always

	 * check for overlap on reflink inodes unless the mapping is already a

	 * COW one.

	 */

	imap_valid = offset_fsb >= wpc->imap.br_startoff &&

		     offset_fsb < wpc->imap.br_startoff + wpc->imap.br_blockcount;

	if (imap_valid &&

	    (!xfs_is_reflink_inode(ip) || wpc->io_type == XFS_IO_COW))

		return 0;



	if (XFS_FORCED_SHUTDOWN(mp))

		return -EIO;



	/*

	 * If we don't have a valid map, now it's time to get a new one for this

	 * offset.  This will convert delayed allocations (including COW ones)

	 * into real extents.  If we return without a valid map, it means we

	 * landed in a hole and we skip the block.

	 */

	xfs_ilock(ip, XFS_ILOCK_SHARED);

	ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||

	       (ip->i_df.if_flags & XFS_IFEXTENTS));
@@ -387,7 +418,6 @@ xfs_map_blocks( 
	if (offset > mp->m_super->s_maxbytes - count)

		count = mp->m_super->s_maxbytes - offset;

	end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);

	offset_fsb = XFS_B_TO_FSBT(mp, offset);



	/*

	 * Check if this is offset is covered by a COW extents, and if yes use
@@ -420,7 +450,7 @@ xfs_map_blocks( 
	/*

	 * Map valid and no COW extent in the way?  We're done.

	 */

	if (wpc->imap_valid) {

	if (imap_valid) {

		xfs_iunlock(ip, XFS_ILOCK_SHARED);

		return 0;

	}
@@ -465,31 +495,6 @@ xfs_map_blocks( 
	return 0;

}



STATIC bool

xfs_imap_valid(

	struct inode		*inode,

	struct xfs_bmbt_irec	*imap,

	xfs_off_t		offset)

{

	offset >>= inode->i_blkbits;



	/*

	 * We have to make sure the cached mapping is within EOF to protect

	 * against eofblocks trimming on file release leaving us with a stale

	 * mapping. Otherwise, a page for a subsequent file extending buffered

	 * write could get picked up by this writeback cycle and written to the

	 * wrong blocks.

	 *

	 * Note that what we really want here is a generic mapping invalidation

	 * mechanism to protect us from arbitrary extent modifying contexts, not

	 * just eofblocks.

	 */

	xfs_trim_extent_eof(imap, XFS_I(inode));



	return offset >= imap->br_startoff &&

		offset < imap->br_startoff + imap->br_blockcount;

}



STATIC void

xfs_start_buffer_writeback(

	struct buffer_head	*bh)
@@ -856,27 +861,10 @@ xfs_writepage_map( 
			continue;

		}



		if (wpc->imap_valid)

			wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap,

							 file_offset);



		/*

		 * COW fork blocks can overlap data fork blocks even if the

		 * blocks aren't shared. COW I/O always takes precedent, so we

		 * must always check for overlap on reflink inodes unless the

		 * mapping is already a COW one.

		 */

		if (!wpc->imap_valid ||

		    (xfs_is_reflink_inode(XFS_I(inode)) &&

		     wpc->io_type != XFS_IO_COW)) {

		error = xfs_map_blocks(wpc, inode, file_offset);

		if (error)

				goto out;

			wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap,

							 file_offset);

		}



		if (!wpc->imap_valid || wpc->io_type == XFS_IO_HOLE)

			break;

		if (wpc->io_type == XFS_IO_HOLE)

			continue;



		lock_buffer(bh);
@@ -887,7 +875,6 @@ xfs_writepage_map( 


	ASSERT(wpc->ioend || list_empty(&submit_list));



out:

	/*

	 * On error, we have to fail the ioend here because we have locked

	 * buffers in the ioend. If we don't do this, we'll deadlock