xfs: allow writeback on pages without buffer heads

Disable the IOMAP_F_BUFFER_HEAD flag on file systems with a block size
equal to the page size, and deal with pages without buffer heads in
writeback.  Thanks to the previous refactoring this is basically trivial
now.

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

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index c8e0d30..0058f98 100644 (file)
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -79,6 +79,19 @@ xfs_find_daxdev_for_inode(
                return mp->m_ddev_targp->bt_daxdev;
 }
 
+static void
+xfs_finish_page_writeback(
+       struct inode            *inode,
+       struct bio_vec          *bvec,
+       int                     error)
+{
+       if (error) {
+               SetPageError(bvec->bv_page);
+               mapping_set_error(inode->i_mapping, -EIO);
+       }
+       end_page_writeback(bvec->bv_page);
+}
+
 /*
  * We're now finished for good with this page.  Update the page state via the
  * associated buffer_heads, paying attention to the start and end offsets that
@@ -91,7 +104,7 @@ xfs_find_daxdev_for_inode(
  * and buffers potentially freed after every call to end_buffer_async_write.
  */
 static void
-xfs_finish_page_writeback(
+xfs_finish_buffer_writeback(
        struct inode            *inode,
        struct bio_vec          *bvec,
        int                     error)
@@ -166,9 +179,12 @@ xfs_destroy_ioend(
                        next = bio->bi_private;
 
                /* walk each page on bio, ending page IO on them */
-               bio_for_each_segment_all(bvec, bio, i)
-                       xfs_finish_page_writeback(inode, bvec, error);
-
+               bio_for_each_segment_all(bvec, bio, i) {
+                       if (page_has_buffers(bvec->bv_page))
+                               xfs_finish_buffer_writeback(inode, bvec, error);
+                       else
+                               xfs_finish_page_writeback(inode, bvec, error);
+               }
                bio_put(bio);
        }
 
@@ -792,13 +808,16 @@ xfs_writepage_map(
 {
        LIST_HEAD(submit_list);
        struct xfs_ioend        *ioend, *next;
-       struct buffer_head      *bh;
+       struct buffer_head      *bh = NULL;
        ssize_t                 len = i_blocksize(inode);
        uint64_t                file_offset;    /* file offset of page */
        unsigned                poffset;        /* offset into page */
        int                     error = 0;
        int                     count = 0;
 
+       if (page_has_buffers(page))
+               bh = page_buffers(page);
+
        /*
         * Walk the blocks on the page, and if we run off the end of the current
         * map or find the current map invalid, grab a new one.  We only use
@@ -806,28 +825,34 @@ xfs_writepage_map(
         * the iteration through the page. This allows us to replace the
         * bufferhead with some other state tracking mechanism in future.
         */
-       file_offset = page_offset(page);
-       bh = page_buffers(page);
-       for (poffset = 0;
+       for (poffset = 0, file_offset = page_offset(page);
             poffset < PAGE_SIZE;
-            poffset += len, file_offset += len, bh = bh->b_this_page) {
+            poffset += len, file_offset += len) {
                /* past the range we are writing, so nothing more to write. */
                if (file_offset >= end_offset)
                        break;
 
-               if (!buffer_uptodate(bh)) {
+               if (bh && !buffer_uptodate(bh)) {
                        if (PageUptodate(page))
                                ASSERT(buffer_mapped(bh));
+                       bh = bh->b_this_page;
                        continue;
                }
 
                error = xfs_map_blocks(wpc, inode, file_offset);
                if (error)
                        break;
-               if (wpc->io_type == XFS_IO_HOLE)
+
+               if (wpc->io_type == XFS_IO_HOLE) {
+                       if (bh)
+                               bh = bh->b_this_page;
                        continue;
+               }
 
-               xfs_map_at_offset(inode, bh, &wpc->imap, file_offset);
+               if (bh) {
+                       xfs_map_at_offset(inode, bh, &wpc->imap, file_offset);
+                       bh = bh->b_this_page;
+               }
                xfs_add_to_ioend(inode, file_offset, page, wpc, wbc,
                                &submit_list);
                count++;
@@ -925,8 +950,6 @@ xfs_do_writepage(
 
        trace_xfs_writepage(inode, page, 0, 0);
 
-       ASSERT(page_has_buffers(page));
-
        /*
         * Refuse to write the page out if we are called from reclaim context.
         *

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 10c54fc..7fe42a1 100644 (file)
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1032,7 +1032,8 @@ xfs_file_iomap_begin(
        if (XFS_FORCED_SHUTDOWN(mp))
                return -EIO;
 
-       iomap->flags |= IOMAP_F_BUFFER_HEAD;
+       if (i_blocksize(inode) < PAGE_SIZE)
+               iomap->flags |= IOMAP_F_BUFFER_HEAD;
 
        if (((flags & (IOMAP_WRITE | IOMAP_DIRECT)) == IOMAP_WRITE) &&
                        !IS_DAX(inode) && !xfs_get_extsz_hint(ip)) {