[XFS] Write at EOF may not update filesize correctly.
authorDavid Chinner <dgc@sgi.com>
Thu, 24 May 2007 05:27:03 +0000 (15:27 +1000)
committerTim Shimmin <tes@chook.melbourne.sgi.com>
Tue, 29 May 2007 08:15:17 +0000 (18:15 +1000)
The recent fix for preventing NULL files from being left around does not
update the file size corectly in all cases. The missing case is a write
extending the file that does not need to allocate a block.

In that case we used a read mapping of the extent which forced the use of
the read I/O completion handler instead of the write I/O completion
handle. Hence the file size was not updated on I/O completion.

SGI-PV: 965068
SGI-Modid: xfs-linux-melb:xfs-kern:28657a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Nathan Scott <nscott@aconex.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>
fs/xfs/linux-2.6/xfs_aops.c

index 4475588e973a4aa922144c80b39df5948b5199ef..7361861e3aacde605a400771af549b77e9b457e5 100644 (file)
@@ -701,7 +701,7 @@ xfs_is_delayed_page(
                        else if (buffer_delay(bh))
                                acceptable = (type == IOMAP_DELAY);
                        else if (buffer_dirty(bh) && buffer_mapped(bh))
-                               acceptable = (type == 0);
+                               acceptable = (type == IOMAP_NEW);
                        else
                                break;
                } while ((bh = bh->b_this_page) != head);
@@ -810,7 +810,7 @@ xfs_convert_page(
                        page_dirty--;
                        count++;
                } else {
-                       type = 0;
+                       type = IOMAP_NEW;
                        if (buffer_mapped(bh) && all_bh && startio) {
                                lock_buffer(bh);
                                xfs_add_to_ioend(inode, bh, offset,
@@ -968,8 +968,8 @@ xfs_page_state_convert(
 
        bh = head = page_buffers(page);
        offset = page_offset(page);
-       flags = -1;
-       type = IOMAP_READ;
+       flags = BMAPI_READ;
+       type = IOMAP_NEW;
 
        /* TODO: cleanup count and page_dirty */
 
@@ -999,14 +999,14 @@ xfs_page_state_convert(
                 *
                 * Third case, an unmapped buffer was found, and we are
                 * in a path where we need to write the whole page out.
-                */
+                */
                if (buffer_unwritten(bh) || buffer_delay(bh) ||
                    ((buffer_uptodate(bh) || PageUptodate(page)) &&
                     !buffer_mapped(bh) && (unmapped || startio))) {
-                       /*
+                       /*
                         * Make sure we don't use a read-only iomap
                         */
-                       if (flags == BMAPI_READ)
+                       if (flags == BMAPI_READ)
                                iomap_valid = 0;
 
                        if (buffer_unwritten(bh)) {
@@ -1055,7 +1055,7 @@ xfs_page_state_convert(
                         * That means it must already have extents allocated
                         * underneath it. Map the extent by reading it.
                         */
-                       if (!iomap_valid || type != IOMAP_READ) {
+                       if (!iomap_valid || flags != BMAPI_READ) {
                                flags = BMAPI_READ;
                                size = xfs_probe_cluster(inode, page, bh,
                                                                head, 1);
@@ -1066,7 +1066,15 @@ xfs_page_state_convert(
                                iomap_valid = xfs_iomap_valid(&iomap, offset);
                        }
 
-                       type = IOMAP_READ;
+                       /*
+                        * We set the type to IOMAP_NEW in case we are doing a
+                        * small write at EOF that is extending the file but
+                        * without needing an allocation. We need to update the
+                        * file size on I/O completion in this case so it is
+                        * the same case as having just allocated a new extent
+                        * that we are writing into for the first time.
+                        */
+                       type = IOMAP_NEW;
                        if (!test_and_set_bit(BH_Lock, &bh->b_state)) {
                                ASSERT(buffer_mapped(bh));
                                if (iomap_valid)