3 files changed, 89 insertions, 2 deletions

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index e47425071e65..1d07dcfbbff3 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1068,10 +1068,10 @@ xfs_file_llseek(
         default:
                 return generic_file_llseek(file, offset, whence);
         case SEEK_HOLE:
-                offset = iomap_seek_hole(inode, offset, &xfs_iomap_ops);
+                offset = iomap_seek_hole(inode, offset, &xfs_seek_iomap_ops);
                 break;
         case SEEK_DATA:
-                offset = iomap_seek_data(inode, offset, &xfs_iomap_ops);
+                offset = iomap_seek_data(inode, offset, &xfs_seek_iomap_ops);
                 break;
         }
 
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 284c5e68f695..df6eda336f17 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1069,6 +1069,92 @@ const struct iomap_ops xfs_iomap_ops = {
 };
 
 static int
+xfs_seek_iomap_begin(
+        struct inode            *inode,
+        loff_t                  offset,
+        loff_t                  length,
+        unsigned                flags,
+        struct iomap            *iomap)
+{
+        struct xfs_inode        *ip = XFS_I(inode);
+        struct xfs_mount        *mp = ip->i_mount;
+        xfs_fileoff_t           offset_fsb = XFS_B_TO_FSBT(mp, offset);
+        xfs_fileoff_t           end_fsb = XFS_B_TO_FSB(mp, offset + length);
+        xfs_fileoff_t           cow_fsb = NULLFILEOFF, data_fsb = NULLFILEOFF;
+        struct xfs_iext_cursor  icur;
+        struct xfs_bmbt_irec    imap, cmap;
+        int                     error = 0;
+        unsigned                lockmode;
+
+        if (XFS_FORCED_SHUTDOWN(mp))
+                return -EIO;
+
+        lockmode = xfs_ilock_data_map_shared(ip);
+        if (!(ip->i_df.if_flags & XFS_IFEXTENTS)) {
+                error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
+                if (error)
+                        goto out_unlock;
+        }
+
+        if (xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap)) {
+                /*
+                 * If we found a data extent we are done.
+                 */
+                if (imap.br_startoff <= offset_fsb)
+                        goto done;
+                data_fsb = imap.br_startoff;
+        } else {
+                /*
+                 * Fake a hole until the end of the file.
+                 */
+                data_fsb = min(XFS_B_TO_FSB(mp, offset + length),
+                               XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
+        }
+
+        /*
+         * If a COW fork extent covers the hole, report it - capped to the next
+         * data fork extent:
+         */
+        if (xfs_inode_has_cow_data(ip) &&
+            xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &cmap))
+                cow_fsb = cmap.br_startoff;
+        if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
+                if (data_fsb < cow_fsb + cmap.br_blockcount)
+                        end_fsb = min(end_fsb, data_fsb);
+                xfs_trim_extent(&cmap, offset_fsb, end_fsb);
+                error = xfs_bmbt_to_iomap(ip, iomap, &cmap, true);
+                /*
+                 * This is a COW extent, so we must probe the page cache
+                 * because there could be dirty page cache being backed
+                 * by this extent.
+                 */
+                iomap->type = IOMAP_UNWRITTEN;
+                goto out_unlock;
+        }
+
+        /*
+         * Else report a hole, capped to the next found data or COW extent.
+         */
+        if (cow_fsb != NULLFILEOFF && cow_fsb < data_fsb)
+                imap.br_blockcount = cow_fsb - offset_fsb;
+        else
+                imap.br_blockcount = data_fsb - offset_fsb;
+        imap.br_startoff = offset_fsb;
+        imap.br_startblock = HOLESTARTBLOCK;
+        imap.br_state = XFS_EXT_NORM;
+done:
+        xfs_trim_extent(&imap, offset_fsb, end_fsb);
+        error = xfs_bmbt_to_iomap(ip, iomap, &imap, false);
+out_unlock:
+        xfs_iunlock(ip, lockmode);
+        return error;
+}
+
+const struct iomap_ops xfs_seek_iomap_ops = {
+        .iomap_begin            = xfs_seek_iomap_begin,
+};
+
+static int
 xfs_xattr_iomap_begin(
         struct inode            *inode,
         loff_t                  offset,
diff --git a/fs/xfs/xfs_iomap.h b/fs/xfs/xfs_iomap.h
index 37b584c3069b..5c2f6aa6d78f 100644
--- a/fs/xfs/xfs_iomap.h
+++ b/fs/xfs/xfs_iomap.h
@@ -40,6 +40,7 @@ xfs_aligned_fsb_count(
 }
 
 extern const struct iomap_ops xfs_iomap_ops;
+extern const struct iomap_ops xfs_seek_iomap_ops;
 extern const struct iomap_ops xfs_xattr_iomap_ops;
 
 #endif /* __XFS_IOMAP_H__*/