xfs: simplify xfs_reflink_convert_cow

Instead of looking up extents to convert and calling xfs_bmapi_write on
each of them just let xfs_bmapi_write handle the full range.  To make
this robust add a new XFS_BMAPI_CONVERT_ONLY that only converts ranges
and never allocates blocks.

[darrick: shorten the stringified CONVERT_ONLY trace flag]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index e48fc5c..af3d18e 100644 (file)
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -4331,7 +4331,8 @@ xfs_bmapi_write(
                 * First, deal with the hole before the allocated space
                 * that we found, if any.
                 */
-               if (need_alloc || wasdelay) {
+               if ((need_alloc || wasdelay) &&
+                   !(flags & XFS_BMAPI_CONVERT_ONLY)) {
                        bma.eof = eof;
                        bma.conv = !!(flags & XFS_BMAPI_CONVERT);
                        bma.wasdel = wasdelay;

diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h
index b6a3959..e36d757 100644 (file)
--- a/fs/xfs/libxfs/xfs_bmap.h
+++ b/fs/xfs/libxfs/xfs_bmap.h
@@ -113,6 +113,9 @@ struct xfs_extent_free_item
 /* 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
+
 #define XFS_BMAPI_FLAGS \
        { XFS_BMAPI_ENTIRE,     "ENTIRE" }, \
        { XFS_BMAPI_METADATA,   "METADATA" }, \
@@ -124,7 +127,8 @@ struct xfs_extent_free_item
        { XFS_BMAPI_ZERO,       "ZERO" }, \
        { XFS_BMAPI_REMAP,      "REMAP" }, \
        { XFS_BMAPI_COWFORK,    "COWFORK" }, \
-       { XFS_BMAPI_DELALLOC,   "DELALLOC" }
+       { XFS_BMAPI_DELALLOC,   "DELALLOC" }, \
+       { XFS_BMAPI_CONVERT_ONLY, "CONVERT_ONLY" }
 
 
 static inline int xfs_bmapi_aflag(int w)

diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index cf976ed..cc041a2 100644 (file)
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -353,29 +353,22 @@ xfs_reflink_convert_cow(
        xfs_off_t               offset,
        xfs_off_t               count)
 {
-       struct xfs_bmbt_irec    got;
-       struct xfs_defer_ops    dfops;
        struct xfs_mount        *mp = ip->i_mount;
-       struct xfs_ifork        *ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
        xfs_fileoff_t           offset_fsb = XFS_B_TO_FSBT(mp, offset);
        xfs_fileoff_t           end_fsb = XFS_B_TO_FSB(mp, offset + count);
-       struct xfs_iext_cursor  icur;
-       bool                    found;
-       int                     error = 0;
-
-       xfs_ilock(ip, XFS_ILOCK_EXCL);
+       xfs_filblks_t           count_fsb = end_fsb - offset_fsb;
+       struct xfs_bmbt_irec    imap;
+       struct xfs_defer_ops    dfops;
+       xfs_fsblock_t           first_block = NULLFSBLOCK;
+       int                     nimaps = 1, error = 0;
 
-       /* Convert all the extents to real from unwritten. */
-       for (found = xfs_iext_lookup_extent(ip, ifp, offset_fsb, &icur, &got);
-            found && got.br_startoff < end_fsb;
-            found = xfs_iext_next_extent(ifp, &icur, &got)) {
-               error = xfs_reflink_convert_cow_extent(ip, &got, offset_fsb,
-                               end_fsb - offset_fsb, &dfops);
-               if (error)
-                       break;
-       }
+       ASSERT(count != 0);
 
-       /* Finish up. */
+       xfs_ilock(ip, XFS_ILOCK_EXCL);
+       error = xfs_bmapi_write(NULL, ip, offset_fsb, count_fsb,
+                       XFS_BMAPI_COWFORK | XFS_BMAPI_CONVERT |
+                       XFS_BMAPI_CONVERT_ONLY, &first_block, 0, &imap, &nimaps,
+                       &dfops);
        xfs_iunlock(ip, XFS_ILOCK_EXCL);
        return error;
 }