1 files changed, 83 insertions, 2 deletions

diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index 8abd12e32e13..4111cd3966c7 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -5471,8 +5471,13 @@ xfs_getbmap(
                         if (error)
                                 goto out_unlock_iolock;
                 }
-
-                ASSERT(ip->i_delayed_blks == 0);
+                /*
+                 * even after flushing the inode, there can still be delalloc
+                 * blocks on the inode beyond EOF due to speculative
+                 * preallocation. These are not removed until the release
+                 * function is called or the inode is inactivated. Hence we
+                 * cannot assert here that ip->i_delayed_blks == 0.
+                 */
         }
 
         lock = xfs_ilock_map_shared(ip);
@@ -6070,3 +6075,79 @@ xfs_bmap_disk_count_leaves(
                 *count += xfs_bmbt_disk_get_blockcount(frp);
         }
 }
+
+/*
+ * dead simple method of punching delalyed allocation blocks from a range in
+ * the inode. Walks a block at a time so will be slow, but is only executed in
+ * rare error cases so the overhead is not critical. This will alays punch out
+ * both the start and end blocks, even if the ranges only partially overlap
+ * them, so it is up to the caller to ensure that partial blocks are not
+ * passed in.
+ */
+int
+xfs_bmap_punch_delalloc_range(
+        struct xfs_inode        *ip,
+        xfs_fileoff_t           start_fsb,
+        xfs_fileoff_t           length)
+{
+        xfs_fileoff_t           remaining = length;
+        int                     error = 0;
+
+        ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+
+        do {
+                int             done;
+                xfs_bmbt_irec_t imap;
+                int             nimaps = 1;
+                xfs_fsblock_t   firstblock;
+                xfs_bmap_free_t flist;
+
+                /*
+                 * Map the range first and check that it is a delalloc extent
+                 * before trying to unmap the range. Otherwise we will be
+                 * trying to remove a real extent (which requires a
+                 * transaction) or a hole, which is probably a bad idea...
+                 */
+                error = xfs_bmapi(NULL, ip, start_fsb, 1,
+                                XFS_BMAPI_ENTIRE,  NULL, 0, &imap,
+                                &nimaps, NULL);
+
+                if (error) {
+                        /* something screwed, just bail */
+                        if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
+                                xfs_fs_cmn_err(CE_ALERT, ip->i_mount,
+                        "Failed delalloc mapping lookup ino %lld fsb %lld.",
+                                                ip->i_ino, start_fsb);
+                        }
+                        break;
+                }
+                if (!nimaps) {
+                        /* nothing there */
+                        goto next_block;
+                }
+                if (imap.br_startblock != DELAYSTARTBLOCK) {
+                        /* been converted, ignore */
+                        goto next_block;
+                }
+                WARN_ON(imap.br_blockcount == 0);
+
+                /*
+                 * Note: while we initialise the firstblock/flist pair, they
+                 * should never be used because blocks should never be
+                 * allocated or freed for a delalloc extent and hence we need
+                 * don't cancel or finish them after the xfs_bunmapi() call.
+                 */
+                xfs_bmap_init(&flist, &firstblock);
+                error = xfs_bunmapi(NULL, ip, start_fsb, 1, 0, 1, &firstblock,
+                                        &flist, &done);
+                if (error)
+                        break;
+
+                ASSERT(!flist.xbf_count && !flist.xbf_first);
+next_block:
+                start_fsb++;
+                remaining--;
+        } while(remaining > 0);
+
+        return error;
+}