1 files changed, 163 insertions, 192 deletions

diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 107bf2a2f344..aac83f9d6107 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -179,7 +179,7 @@ xfs_reflink_trim_around_shared(
 	int			error = 0;
 
 	/* Holes, unwritten, and delalloc extents cannot be shared */
-	if (!xfs_is_cow_inode(ip) || !xfs_bmap_is_real_extent(irec)) {
+	if (!xfs_is_cow_inode(ip) || !xfs_bmap_is_written_extent(irec)) {
 		*shared = false;
 		return 0;
 	}
@@ -655,7 +655,7 @@ xfs_reflink_end_cow_extent(
 	 * preallocations can leak into the range we are called upon, and we
 	 * need to skip them.
 	 */
-	if (!xfs_bmap_is_real_extent(&got)) {
+	if (!xfs_bmap_is_written_extent(&got)) {
 		*end_fsb = del.br_startoff;
 		goto out_cancel;
 	}
@@ -984,40 +984,28 @@ xfs_reflink_ag_has_free_space(
 }
 
 /*
- * Unmap a range of blocks from a file, then map other blocks into the hole.
- * The range to unmap is (destoff : destoff + srcioff + irec->br_blockcount).
- * The extent irec is mapped into dest at irec->br_startoff.
+ * Remap the given extent into the file.  The dmap blockcount will be set to
+ * the number of blocks that were actually remapped.
  */
 STATIC int
 xfs_reflink_remap_extent(
 	struct xfs_inode	*ip,
-	struct xfs_bmbt_irec	*irec,
-	xfs_fileoff_t		destoff,
+	struct xfs_bmbt_irec	*dmap,
 	xfs_off_t		new_isize)
 {
+	struct xfs_bmbt_irec	smap;
 	struct xfs_mount	*mp = ip->i_mount;
-	bool			real_extent = xfs_bmap_is_real_extent(irec);
 	struct xfs_trans	*tp;
-	unsigned int		resblks;
-	struct xfs_bmbt_irec	uirec;
-	xfs_filblks_t		rlen;
-	xfs_filblks_t		unmap_len;
 	xfs_off_t		newlen;
+	int64_t			qres, qdelta;
+	unsigned int		resblks;
+	bool			smap_real;
+	bool			dmap_written = xfs_bmap_is_written_extent(dmap);
+	int			nimaps;
 	int			error;
 
-	unmap_len = irec->br_startoff + irec->br_blockcount - destoff;
-	trace_xfs_reflink_punch_range(ip, destoff, unmap_len);
-
-	/* No reflinking if we're low on space */
-	if (real_extent) {
-		error = xfs_reflink_ag_has_free_space(mp,
-				XFS_FSB_TO_AGNO(mp, irec->br_startblock));
-		if (error)
-			goto out;
-	}
-
 	/* Start a rolling transaction to switch the mappings */
-	resblks = XFS_EXTENTADD_SPACE_RES(ip->i_mount, XFS_DATA_FORK);
+	resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp);
 	if (error)
 		goto out;
@@ -1025,87 +1013,147 @@ xfs_reflink_remap_extent(
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	xfs_trans_ijoin(tp, ip, 0);
 
-	/* If we're not just clearing space, then do we have enough quota? */
-	if (real_extent) {
-		error = xfs_trans_reserve_quota_nblks(tp, ip,
-				irec->br_blockcount, 0, XFS_QMOPT_RES_REGBLKS);
+	/*
+	 * Read what's currently mapped in the destination file into smap.
+	 * If smap isn't a hole, we will have to remove it before we can add
+	 * dmap to the destination file.
+	 */
+	nimaps = 1;
+	error = xfs_bmapi_read(ip, dmap->br_startoff, dmap->br_blockcount,
+			&smap, &nimaps, 0);
+	if (error)
+		goto out_cancel;
+	ASSERT(nimaps == 1 && smap.br_startoff == dmap->br_startoff);
+	smap_real = xfs_bmap_is_real_extent(&smap);
+
+	/*
+	 * We can only remap as many blocks as the smaller of the two extent
+	 * maps, because we can only remap one extent at a time.
+	 */
+	dmap->br_blockcount = min(dmap->br_blockcount, smap.br_blockcount);
+	ASSERT(dmap->br_blockcount == smap.br_blockcount);
+
+	trace_xfs_reflink_remap_extent_dest(ip, &smap);
+
+	/*
+	 * Two extents mapped to the same physical block must not have
+	 * different states; that's filesystem corruption.  Move on to the next
+	 * extent if they're both holes or both the same physical extent.
+	 */
+	if (dmap->br_startblock == smap.br_startblock) {
+		if (dmap->br_state != smap.br_state)
+			error = -EFSCORRUPTED;
+		goto out_cancel;
+	}
+
+	/* If both extents are unwritten, leave them alone. */
+	if (dmap->br_state == XFS_EXT_UNWRITTEN &&
+	    smap.br_state == XFS_EXT_UNWRITTEN)
+		goto out_cancel;
+
+	/* No reflinking if the AG of the dest mapping is low on space. */
+	if (dmap_written) {
+		error = xfs_reflink_ag_has_free_space(mp,
+				XFS_FSB_TO_AGNO(mp, dmap->br_startblock));
 		if (error)
 			goto out_cancel;
 	}
 
-	trace_xfs_reflink_remap(ip, irec->br_startoff,
-				irec->br_blockcount, irec->br_startblock);
-
-	/* Unmap the old blocks in the data fork. */
-	rlen = unmap_len;
-	while (rlen) {
-		ASSERT(tp->t_firstblock == NULLFSBLOCK);
-		error = __xfs_bunmapi(tp, ip, destoff, &rlen, 0, 1);
+	/*
+	 * Compute quota reservation if we think the quota block counter for
+	 * this file could increase.
+	 *
+	 * Adding a written extent to the extent map can cause a bmbt split,
+	 * and removing a mapped extent from the extent can cause a bmbt split.
+	 * The two operations cannot both cause a split since they operate on
+	 * the same index in the bmap btree, so we only need a reservation for
+	 * one bmbt split if either thing is happening.
+	 *
+	 * If we are mapping a written extent into the file, we need to have
+	 * enough quota block count reservation to handle the blocks in that
+	 * extent.  We log only the delta to the quota block counts, so if the
+	 * extent we're unmapping also has blocks allocated to it, we don't
+	 * need a quota reservation for the extent itself.
+	 *
+	 * Note that if we're replacing a delalloc reservation with a written
+	 * extent, we have to take the full quota reservation because removing
+	 * the delalloc reservation gives the block count back to the quota
+	 * count.  This is suboptimal, but the VFS flushed the dest range
+	 * before we started.  That should have removed all the delalloc
+	 * reservations, but we code defensively.
+	 */
+	qres = qdelta = 0;
+	if (smap_real || dmap_written)
+		qres = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
+	if (!smap_real && dmap_written)
+		qres += dmap->br_blockcount;
+	if (qres > 0) {
+		error = xfs_trans_reserve_quota_nblks(tp, ip, qres, 0,
+				XFS_QMOPT_RES_REGBLKS);
 		if (error)
 			goto out_cancel;
+	}
 
+	if (smap_real) {
 		/*
-		 * Trim the extent to whatever got unmapped.
-		 * Remember, bunmapi works backwards.
+		 * If the extent we're unmapping is backed by storage (written
+		 * or not), unmap the extent and drop its refcount.
 		 */
-		uirec.br_startblock = irec->br_startblock + rlen;
-		uirec.br_startoff = irec->br_startoff + rlen;
-		uirec.br_blockcount = unmap_len - rlen;
-		uirec.br_state = irec->br_state;
-		unmap_len = rlen;
-
-		/* If this isn't a real mapping, we're done. */
-		if (!real_extent || uirec.br_blockcount == 0)
-			goto next_extent;
+		xfs_bmap_unmap_extent(tp, ip, &smap);
+		xfs_refcount_decrease_extent(tp, &smap);
+		qdelta -= smap.br_blockcount;
+	} else if (smap.br_startblock == DELAYSTARTBLOCK) {
+		xfs_filblks_t	len = smap.br_blockcount;
 
-		trace_xfs_reflink_remap(ip, uirec.br_startoff,
-				uirec.br_blockcount, uirec.br_startblock);
-
-		/* Update the refcount tree */
-		xfs_refcount_increase_extent(tp, &uirec);
-
-		/* Map the new blocks into the data fork. */
-		xfs_bmap_map_extent(tp, ip, &uirec);
+		/*
+		 * If the extent we're unmapping is a delalloc reservation,
+		 * we can use the regular bunmapi function to release the
+		 * incore state.  Dropping the delalloc reservation takes care
+		 * of the quota reservation for us.
+		 */
+		error = __xfs_bunmapi(NULL, ip, smap.br_startoff, &len, 0, 1);
+		if (error)
+			goto out_cancel;
+		ASSERT(len == 0);
+	}
 
-		/* Update quota accounting. */
-		xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT,
-				uirec.br_blockcount);
+	/*
+	 * If the extent we're sharing is backed by written storage, increase
+	 * its refcount and map it into the file.
+	 */
+	if (dmap_written) {
+		xfs_refcount_increase_extent(tp, dmap);
+		xfs_bmap_map_extent(tp, ip, dmap);
+		qdelta += dmap->br_blockcount;
+	}
 
-		/* Update dest isize if needed. */
-		newlen = XFS_FSB_TO_B(mp,
-				uirec.br_startoff + uirec.br_blockcount);
-		newlen = min_t(xfs_off_t, newlen, new_isize);
-		if (newlen > i_size_read(VFS_I(ip))) {
-			trace_xfs_reflink_update_inode_size(ip, newlen);
-			i_size_write(VFS_I(ip), newlen);
-			ip->i_d.di_size = newlen;
-			xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
-		}
+	xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, qdelta);
 
-next_extent:
-		/* Process all the deferred stuff. */
-		error = xfs_defer_finish(&tp);
-		if (error)
-			goto out_cancel;
+	/* Update dest isize if needed. */
+	newlen = XFS_FSB_TO_B(mp, dmap->br_startoff + dmap->br_blockcount);
+	newlen = min_t(xfs_off_t, newlen, new_isize);
+	if (newlen > i_size_read(VFS_I(ip))) {
+		trace_xfs_reflink_update_inode_size(ip, newlen);
+		i_size_write(VFS_I(ip), newlen);
+		ip->i_d.di_size = newlen;
+		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 	}
 
+	/* Commit everything and unlock. */
 	error = xfs_trans_commit(tp);
-	xfs_iunlock(ip, XFS_ILOCK_EXCL);
-	if (error)
-		goto out;
-	return 0;
+	goto out_unlock;
 
 out_cancel:
 	xfs_trans_cancel(tp);
+out_unlock:
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 out:
-	trace_xfs_reflink_remap_extent_error(ip, error, _RET_IP_);
+	if (error)
+		trace_xfs_reflink_remap_extent_error(ip, error, _RET_IP_);
 	return error;
 }
 
-/*
- * Iteratively remap one file's extents (and holes) to another's.
- */
+/* Remap a range of one file to the other. */
 int
 xfs_reflink_remap_blocks(
 	struct xfs_inode	*src,
@@ -1116,25 +1164,22 @@ xfs_reflink_remap_blocks(
 	loff_t			*remapped)
 {
 	struct xfs_bmbt_irec	imap;
-	xfs_fileoff_t		srcoff;
-	xfs_fileoff_t		destoff;
+	struct xfs_mount	*mp = src->i_mount;
+	xfs_fileoff_t		srcoff = XFS_B_TO_FSBT(mp, pos_in);
+	xfs_fileoff_t		destoff = XFS_B_TO_FSBT(mp, pos_out);
 	xfs_filblks_t		len;
-	xfs_filblks_t		range_len;
 	xfs_filblks_t		remapped_len = 0;
 	xfs_off_t		new_isize = pos_out + remap_len;
 	int			nimaps;
 	int			error = 0;
 
-	destoff = XFS_B_TO_FSBT(src->i_mount, pos_out);
-	srcoff = XFS_B_TO_FSBT(src->i_mount, pos_in);
-	len = XFS_B_TO_FSB(src->i_mount, remap_len);
+	len = min_t(xfs_filblks_t, XFS_B_TO_FSB(mp, remap_len),
+			XFS_MAX_FILEOFF);
 
-	/* drange = (destoff, destoff + len); srange = (srcoff, srcoff + len) */
-	while (len) {
-		uint		lock_mode;
+	trace_xfs_reflink_remap_blocks(src, srcoff, len, dest, destoff);
 
-		trace_xfs_reflink_remap_blocks_loop(src, srcoff, len,
-				dest, destoff);
+	while (len > 0) {
+		unsigned int	lock_mode;
 
 		/* Read extent from the source file */
 		nimaps = 1;
@@ -1143,18 +1188,25 @@ xfs_reflink_remap_blocks(
 		xfs_iunlock(src, lock_mode);
 		if (error)
 			break;
-		ASSERT(nimaps == 1);
-
-		trace_xfs_reflink_remap_imap(src, srcoff, len, XFS_DATA_FORK,
-				&imap);
+		/*
+		 * The caller supposedly flushed all dirty pages in the source
+		 * file range, which means that writeback should have allocated
+		 * or deleted all delalloc reservations in that range.  If we
+		 * find one, that's a good sign that something is seriously
+		 * wrong here.
+		 */
+		ASSERT(nimaps == 1 && imap.br_startoff == srcoff);
+		if (imap.br_startblock == DELAYSTARTBLOCK) {
+			ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
+			error = -EFSCORRUPTED;
+			break;
+		}
 
-		/* Translate imap into the destination file. */
-		range_len = imap.br_startoff + imap.br_blockcount - srcoff;
-		imap.br_startoff += destoff - srcoff;
+		trace_xfs_reflink_remap_extent_src(src, &imap);
 
-		/* Clear dest from destoff to the end of imap and map it in. */
-		error = xfs_reflink_remap_extent(dest, &imap, destoff,
-				new_isize);
+		/* Remap into the destination file at the given offset. */
+		imap.br_startoff = destoff;
+		error = xfs_reflink_remap_extent(dest, &imap, new_isize);
 		if (error)
 			break;
 
@@ -1164,10 +1216,10 @@ xfs_reflink_remap_blocks(
 		}
 
 		/* Advance drange/srange */
-		srcoff += range_len;
-		destoff += range_len;
-		len -= range_len;
-		remapped_len += range_len;
+		srcoff += imap.br_blockcount;
+		destoff += imap.br_blockcount;
+		len -= imap.br_blockcount;
+		remapped_len += imap.br_blockcount;
 	}
 
 	if (error)
@@ -1178,81 +1230,6 @@ xfs_reflink_remap_blocks(
 }
 
 /*
- * Grab the exclusive iolock for a data copy from src to dest, making sure to
- * abide vfs locking order (lowest pointer value goes first) and breaking the
- * layout leases before proceeding.  The loop is needed because we cannot call
- * the blocking break_layout() with the iolocks held, and therefore have to
- * back out both locks.
- */
-static int
-xfs_iolock_two_inodes_and_break_layout(
-	struct inode		*src,
-	struct inode		*dest)
-{
-	int			error;
-
-	if (src > dest)
-		swap(src, dest);
-
-retry:
-	/* Wait to break both inodes' layouts before we start locking. */
-	error = break_layout(src, true);
-	if (error)
-		return error;
-	if (src != dest) {
-		error = break_layout(dest, true);
-		if (error)
-			return error;
-	}
-
-	/* Lock one inode and make sure nobody got in and leased it. */
-	inode_lock(src);
-	error = break_layout(src, false);
-	if (error) {
-		inode_unlock(src);
-		if (error == -EWOULDBLOCK)
-			goto retry;
-		return error;
-	}
-
-	if (src == dest)
-		return 0;
-
-	/* Lock the other inode and make sure nobody got in and leased it. */
-	inode_lock_nested(dest, I_MUTEX_NONDIR2);
-	error = break_layout(dest, false);
-	if (error) {
-		inode_unlock(src);
-		inode_unlock(dest);
-		if (error == -EWOULDBLOCK)
-			goto retry;
-		return error;
-	}
-
-	return 0;
-}
-
-/* Unlock both inodes after they've been prepped for a range clone. */
-void
-xfs_reflink_remap_unlock(
-	struct file		*file_in,
-	struct file		*file_out)
-{
-	struct inode		*inode_in = file_inode(file_in);
-	struct xfs_inode	*src = XFS_I(inode_in);
-	struct inode		*inode_out = file_inode(file_out);
-	struct xfs_inode	*dest = XFS_I(inode_out);
-	bool			same_inode = (inode_in == inode_out);
-
-	xfs_iunlock(dest, XFS_MMAPLOCK_EXCL);
-	if (!same_inode)
-		xfs_iunlock(src, XFS_MMAPLOCK_EXCL);
-	inode_unlock(inode_out);
-	if (!same_inode)
-		inode_unlock(inode_in);
-}
-
-/*
  * If we're reflinking to a point past the destination file's EOF, we must
  * zero any speculative post-EOF preallocations that sit between the old EOF
  * and the destination file offset.
@@ -1314,18 +1291,12 @@ xfs_reflink_remap_prep(
 	struct xfs_inode	*src = XFS_I(inode_in);
 	struct inode		*inode_out = file_inode(file_out);
 	struct xfs_inode	*dest = XFS_I(inode_out);
-	bool			same_inode = (inode_in == inode_out);
-	ssize_t			ret;
+	int			ret;
 
 	/* Lock both files against IO */
-	ret = xfs_iolock_two_inodes_and_break_layout(inode_in, inode_out);
+	ret = xfs_ilock2_io_mmap(src, dest);
 	if (ret)
 		return ret;
-	if (same_inode)
-		xfs_ilock(src, XFS_MMAPLOCK_EXCL);
-	else
-		xfs_lock_two_inodes(src, XFS_MMAPLOCK_EXCL, dest,
-				XFS_MMAPLOCK_EXCL);
 
 	/* Check file eligibility and prepare for block sharing. */
 	ret = -EINVAL;
@@ -1339,7 +1310,7 @@ xfs_reflink_remap_prep(
 
 	ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out,
 			len, remap_flags);
-	if (ret < 0 || *len == 0)
+	if (ret || *len == 0)
 		goto out_unlock;
 
 	/* Attach dquots to dest inode before changing block map */
@@ -1374,9 +1345,9 @@ xfs_reflink_remap_prep(
 	if (ret)
 		goto out_unlock;
 
-	return 1;
+	return 0;
 out_unlock:
-	xfs_reflink_remap_unlock(file_in, file_out);
+	xfs_iunlock2_io_mmap(src, dest);
 	return ret;
 }