xfs: return work remaining at the end of a bunmapi operation

Return the range of file blocks that bunmapi didn't free.  This hint
is used by CoW and reflink to figure out what part of an extent
actually got freed so that it can set up the appropriate atomic
remapping of just the freed range.

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

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 5828814c119c63d0c667c730a8683b45119ecd15..2be1fd3fac471286be63b53c7bbc1c40d8d6352f 100644 (file)
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -5098,17 +5098,16 @@ done:
  * *done is set.
  */
 int                                            /* error */
-xfs_bunmapi(
+__xfs_bunmapi(
        xfs_trans_t             *tp,            /* transaction pointer */
        struct xfs_inode        *ip,            /* incore inode */
        xfs_fileoff_t           bno,            /* starting offset to unmap */
-       xfs_filblks_t           len,            /* length to unmap in file */
+       xfs_filblks_t           *rlen,          /* i/o: amount remaining */
        int                     flags,          /* misc flags */
        xfs_extnum_t            nexts,          /* number of extents max */
        xfs_fsblock_t           *firstblock,    /* first allocated block
                                                   controls a.g. for allocs */
-       struct xfs_defer_ops    *dfops,         /* i/o: list extents to free */
-       int                     *done)          /* set if not done yet */
+       struct xfs_defer_ops    *dfops)         /* i/o: deferred updates */
 {
        xfs_btree_cur_t         *cur;           /* bmap btree cursor */
        xfs_bmbt_irec_t         del;            /* extent being deleted */
@@ -5130,6 +5129,7 @@ xfs_bunmapi(
        int                     wasdel;         /* was a delayed alloc extent */
        int                     whichfork;      /* data or attribute fork */
        xfs_fsblock_t           sum;
+       xfs_filblks_t           len = *rlen;    /* length to unmap in file */
 
        trace_xfs_bunmap(ip, bno, len, flags, _RET_IP_);
 
@@ -5156,7 +5156,7 @@ xfs_bunmapi(
                return error;
        nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
        if (nextents == 0) {
-               *done = 1;
+               *rlen = 0;
                return 0;
        }
        XFS_STATS_INC(mp, xs_blk_unmap);
@@ -5427,7 +5427,10 @@ nodelete:
                        extno++;
                }
        }
-       *done = bno == (xfs_fileoff_t)-1 || bno < start || lastx < 0;
+       if (bno == (xfs_fileoff_t)-1 || bno < start || lastx < 0)
+               *rlen = 0;
+       else
+               *rlen = bno - start + 1;
 
        /*
         * Convert to a btree if necessary.
@@ -5483,6 +5486,27 @@ error0:
        return error;
 }
 
+/* Unmap a range of a file. */
+int
+xfs_bunmapi(
+       xfs_trans_t             *tp,
+       struct xfs_inode        *ip,
+       xfs_fileoff_t           bno,
+       xfs_filblks_t           len,
+       int                     flags,
+       xfs_extnum_t            nexts,
+       xfs_fsblock_t           *firstblock,
+       struct xfs_defer_ops    *dfops,
+       int                     *done)
+{
+       int                     error;
+
+       error = __xfs_bunmapi(tp, ip, bno, &len, flags, nexts, firstblock,
+                       dfops);
+       *done = (len == 0);
+       return error;
+}
+
 /*
  * Determine whether an extent shift can be accomplished by a merge with the
  * extent that precedes the target hole of the shift.

diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h
index b40ef797a4bf968ca5ec0f2f06660d980262ac90..85e3b9d91ade2da00bfd279c674fd3379372c16c 100644 (file)
--- a/fs/xfs/libxfs/xfs_bmap.h
+++ b/fs/xfs/libxfs/xfs_bmap.h
@@ -197,6 +197,10 @@ int        xfs_bmapi_write(struct xfs_trans *tp, struct xfs_inode *ip,
                xfs_fsblock_t *firstblock, xfs_extlen_t total,
                struct xfs_bmbt_irec *mval, int *nmap,
                struct xfs_defer_ops *dfops);
+int    __xfs_bunmapi(struct xfs_trans *tp, struct xfs_inode *ip,
+               xfs_fileoff_t bno, xfs_filblks_t *rlen, int flags,
+               xfs_extnum_t nexts, xfs_fsblock_t *firstblock,
+               struct xfs_defer_ops *dfops);
 int    xfs_bunmapi(struct xfs_trans *tp, struct xfs_inode *ip,
                xfs_fileoff_t bno, xfs_filblks_t len, int flags,
                xfs_extnum_t nexts, xfs_fsblock_t *firstblock,