Commit d8ae82e3 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Darrick J. Wong
Browse files

xfs: split XFS_BMAPI_DELALLOC handling from xfs_bmapi_write 



Delalloc conversion has traditionally been part of our function to
allocate blocks on disk (first xfs_bmapi, then xfs_bmapi_write), but
delalloc conversion is a little special as we really do not want
to allocate blocks over holes, for which we don't have reservations.

Split the delalloc conversions into a separate helper to keep the
code simple and structured.

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 c8b54673

fs/xfs/libxfs/xfs_bmap.c

+58 −48
Original line number Diff line number Diff line
@@ -4327,22 +4327,6 @@ xfs_bmapi_write( 
	bma.datatype = 0;

	bma.minleft = xfs_bmapi_minleft(tp, ip, whichfork);



	/*

	 * The delalloc flag means the caller wants to allocate the entire

	 * delalloc extent backing bno where bno may not necessarily match the

	 * startoff. Now that we've looked up the extent, reset the range to

	 * map based on the extent in the file. If we're in a hole, this may be

	 * an error so don't adjust anything.

	 */

	if ((flags & XFS_BMAPI_DELALLOC) &&

	    !eof && bno >= bma.got.br_startoff) {

		bno = bma.got.br_startoff;

		len = bma.got.br_blockcount;

#ifdef DEBUG

		orig_bno = bno;

		orig_len = len;

#endif

	}

	n = 0;

	end = bno + len;

	obno = bno;
@@ -4359,26 +4343,7 @@ xfs_bmapi_write( 
			ASSERT(!((flags & XFS_BMAPI_CONVERT) &&

			         (flags & XFS_BMAPI_COWFORK)));



			if (flags & XFS_BMAPI_DELALLOC) {

				/*

				 * For the COW fork we can reasonably get a

				 * request for converting an extent that races

				 * with other threads already having converted

				 * part of it, as there converting COW to

				 * regular blocks is not protected using the

				 * IOLOCK.

				 */

				ASSERT(flags & XFS_BMAPI_COWFORK);

				if (!(flags & XFS_BMAPI_COWFORK)) {

					error = -EIO;

					goto error0;

				}



				if (eof || bno >= end)

					break;

			} else {

			need_alloc = true;

			}

		} else if (isnullstartblock(bma.got.br_startblock)) {

			wasdelay = true;

		}
@@ -4487,23 +4452,68 @@ xfs_bmapi_convert_delalloc( 
	int			whichfork,

	struct xfs_bmbt_irec	*imap)

{

	int			flags = XFS_BMAPI_DELALLOC;

	int			nimaps = 1;

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

	struct xfs_bmalloca	bma = { NULL };

	int			error;

	int			total = XFS_EXTENTADD_SPACE_RES(ip->i_mount,

								XFS_DATA_FORK);



	if (whichfork == XFS_COW_FORK)

		flags |= XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC;

	if (!xfs_iext_lookup_extent(ip, ifp, offset_fsb, &bma.icur, &bma.got) ||

	    bma.got.br_startoff > offset_fsb) {

		/*

		 * No extent found in the range we are trying to convert.  This

		 * should only happen for the COW fork, where another thread

		 * might have moved the extent to the data fork in the meantime.

		 */

		WARN_ON_ONCE(whichfork != XFS_COW_FORK);

		return -EAGAIN;

	}



	/*

	 * The delalloc flag means to allocate the entire extent; pass a dummy

	 * length of 1.

	 * If we find a real extent here we raced with another thread converting

	 * the extent.  Just return the real extent at this offset.

	 */

	error = xfs_bmapi_write(tp, ip, offset_fsb, 1, flags, total, imap,

				&nimaps);

	if (!error && !nimaps)

	if (!isnullstartblock(bma.got.br_startblock)) {

		*imap = bma.got;

		return 0;

	}



	bma.tp = tp;

	bma.ip = ip;

	bma.wasdel = true;

	bma.offset = bma.got.br_startoff;

	bma.length = max_t(xfs_filblks_t, bma.got.br_blockcount, MAXEXTLEN);

	bma.total = XFS_EXTENTADD_SPACE_RES(ip->i_mount, XFS_DATA_FORK);

	bma.minleft = xfs_bmapi_minleft(tp, ip, whichfork);

	if (whichfork == XFS_COW_FORK)

		bma.flags = XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC;



	if (!xfs_iext_peek_prev_extent(ifp, &bma.icur, &bma.prev))

		bma.prev.br_startoff = NULLFILEOFF;



	error = xfs_bmapi_allocate(&bma);

	if (error)

		goto out_finish;



	error = -ENOSPC;

	if (WARN_ON_ONCE(bma.blkno == NULLFSBLOCK))

		goto out_finish;

	error = -EFSCORRUPTED;

	if (WARN_ON_ONCE(!bma.got.br_startblock && !XFS_IS_REALTIME_INODE(ip)))

		goto out_finish;



	ASSERT(!isnullstartblock(bma.got.br_startblock));

	*imap = bma.got;



	if (whichfork == XFS_COW_FORK) {

		error = xfs_refcount_alloc_cow_extent(tp, bma.blkno,

				bma.length);

		if (error)

			goto out_finish;

	}



	error = xfs_bmap_btree_to_extents(tp, ip, bma.cur, &bma.logflags,

			whichfork);

out_finish:

	xfs_bmapi_finish(&bma, whichfork, error);

	return error;

}

fs/xfs/libxfs/xfs_bmap.h

+0 −4
Original line number Diff line number Diff line
@@ -95,9 +95,6 @@ struct xfs_extent_free_item 
/* Map something in the CoW fork. */

#define XFS_BMAPI_COWFORK	0x200



/* Only convert delalloc space, don't allocate entirely new extents */

#define XFS_BMAPI_DELALLOC	0x400



/* Only convert unwritten extents, don't allocate new blocks */

#define XFS_BMAPI_CONVERT_ONLY	0x800
@@ -117,7 +114,6 @@ struct xfs_extent_free_item 
	{ XFS_BMAPI_ZERO,	"ZERO" }, \

	{ XFS_BMAPI_REMAP,	"REMAP" }, \

	{ XFS_BMAPI_COWFORK,	"COWFORK" }, \

	{ XFS_BMAPI_DELALLOC,	"DELALLOC" }, \

	{ XFS_BMAPI_CONVERT_ONLY, "CONVERT_ONLY" }, \

	{ XFS_BMAPI_NODISCARD,	"NODISCARD" }, \

	{ XFS_BMAPI_NORMAP,	"NORMAP" }

CRA Git | Maintained and supported by SUSTech CRA and CCSE