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Commit 5936dc54 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Darrick J. Wong
Browse files

xfs: don't rely on extent indices in xfs_bmap_insert_extents 



Rewrite xfs_bmap_insert_extents so that we don't rely on extent indices
except for iterating over them.  Not being able to iterate to the previous
extent or finding the extent that stop_fsb is in are sufficient exit
conditions, and we don't need to do any extent count games given that:

  a) we already flushed all delalloc extents past our start offset
     before doing the operation
  b) xfs_iext_count() includes delalloc extents anyway

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent 40591bdb

fs/xfs/libxfs/xfs_bmap.c

+9 −38
Original line number Diff line number Diff line
@@ -5737,10 +5737,8 @@ xfs_bmap_insert_extents( 
	struct xfs_mount	*mp = ip->i_mount;

	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, whichfork);

	struct xfs_btree_cur	*cur = NULL;

	struct xfs_bmbt_irec	got, next, s;

	struct xfs_bmbt_irec	got, next;

	xfs_extnum_t		current_ext;

	xfs_extnum_t		total_extents;

	xfs_extnum_t		stop_extent;

	xfs_fileoff_t		new_startoff;

	int			error = 0;

	int			logflags = 0;
@@ -5771,37 +5769,14 @@ xfs_bmap_insert_extents( 
		cur->bc_private.b.flags = 0;

	}



	/*

	 * There may be delalloc extents in the data fork before the range we

	 * are collapsing out, so we cannot use the count of real extents here.

	 * Instead we have to calculate it from the incore fork.

	 */

	total_extents = xfs_iext_count(ifp);

	if (total_extents == 0) {

		*done = true;

		goto del_cursor;

	}



	/*

	 * In case of first right shift, we need to initialize next_fsb

	 */

	if (*next_fsb == NULLFSBLOCK) {

		current_ext = total_extents - 1;

		xfs_iext_get_extent(ifp, current_ext, &got);

		if (stop_fsb > got.br_startoff) {

		current_ext = xfs_iext_count(ifp) - 1;

		if (!xfs_iext_get_extent(ifp, current_ext, &got) ||

		    stop_fsb > got.br_startoff) {

			*done = true;

			goto del_cursor;

		}

		*next_fsb = got.br_startoff;

	} else {

		/*

		 * Look up the extent index for the fsb where we start shifting. We can

		 * henceforth iterate with current_ext as extent list changes are locked

		 * out via ilock.

		 *

		 * If next_fsb lies in a hole beyond which there are no extents we are

		 * done.

		 */

		if (!xfs_iext_lookup_extent(ip, ifp, *next_fsb, &current_ext,

				&got)) {

			*done = true;
@@ -5810,18 +5785,13 @@ xfs_bmap_insert_extents( 
	}

	XFS_WANT_CORRUPTED_RETURN(mp, !isnullstartblock(got.br_startblock));



	/* Lookup the extent index at which we have to stop */

	xfs_iext_lookup_extent(ip, ifp, stop_fsb, &stop_extent, &s);

	/* Make stop_extent exclusive of shift range */

	stop_extent--;

	if (current_ext <= stop_extent) {

	if (stop_fsb >= got.br_startoff + got.br_blockcount) {

		error = -EIO;

		goto del_cursor;

	}



	new_startoff = got.br_startoff + offset_shift_fsb;

	if (current_ext < total_extents - 1) {

		xfs_iext_get_extent(ifp, current_ext + 1, &next);

	if (xfs_iext_get_extent(ifp, current_ext + 1, &next)) {

		if (new_startoff + got.br_blockcount > next.br_startoff) {

			error = -EINVAL;

			goto del_cursor;
@@ -5841,11 +5811,12 @@ xfs_bmap_insert_extents( 
			cur, &logflags, dfops, new_startoff);

	if (error)

		goto del_cursor;

	if (--current_ext == stop_extent) {



	if (!xfs_iext_get_extent(ifp, --current_ext, &got) ||

	    stop_fsb >= got.br_startoff + got.br_blockcount) {

		*done = true;

		goto del_cursor;

	}

	xfs_iext_get_extent(ifp, current_ext, &got);



	*next_fsb = got.br_startoff;

del_cursor: