NTFS: Fix page_has_buffers()/page_buffers() handling in fs/ntfs/aops.c.

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>

diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog
index c3b5102..029f856 100644 (file)
--- a/fs/ntfs/ChangeLog
+++ b/fs/ntfs/ChangeLog
@@ -85,6 +85,7 @@ ToDo/Notes:
          removal of the get_bh()/put_bh() pairs for each buffer.
        - Fix fs/ntfs/aops.c::ntfs_{read,write}_block() to handle the case
          where a concurrent truncate has truncated the runlist under our feet.
+       - Fix page_has_buffers()/page_buffers() handling in fs/ntfs/aops.c.
 
 2.1.23 - Implement extension of resident files and make writing safe as well as
         many bug fixes, cleanups, and enhancements...

diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c
index 2482b67..52e1aff 100644 (file)
--- a/fs/ntfs/aops.c
+++ b/fs/ntfs/aops.c
@@ -185,13 +185,15 @@ static int ntfs_read_block(struct page *page)
        blocksize_bits = VFS_I(ni)->i_blkbits;
        blocksize = 1 << blocksize_bits;
 
-       if (!page_has_buffers(page))
+       if (!page_has_buffers(page)) {
                create_empty_buffers(page, blocksize, 0);
-       bh = head = page_buffers(page);
-       if (unlikely(!bh)) {
-               unlock_page(page);
-               return -ENOMEM;
+               if (unlikely(!page_has_buffers(page))) {
+                       unlock_page(page);
+                       return -ENOMEM;
+               }
        }
+       bh = head = page_buffers(page);
+       BUG_ON(!bh);
 
        iblock = (s64)page->index << (PAGE_CACHE_SHIFT - blocksize_bits);
        read_lock_irqsave(&ni->size_lock, flags);
@@ -530,19 +532,21 @@ static int ntfs_write_block(struct page *page, struct writeback_control *wbc)
                BUG_ON(!PageUptodate(page));
                create_empty_buffers(page, blocksize,
                                (1 << BH_Uptodate) | (1 << BH_Dirty));
+               if (unlikely(!page_has_buffers(page))) {
+                       ntfs_warning(vol->sb, "Error allocating page "
+                                       "buffers.  Redirtying page so we try "
+                                       "again later.");
+                       /*
+                        * Put the page back on mapping->dirty_pages, but leave
+                        * its buffers' dirty state as-is.
+                        */
+                       redirty_page_for_writepage(wbc, page);
+                       unlock_page(page);
+                       return 0;
+               }
        }
        bh = head = page_buffers(page);
-       if (unlikely(!bh)) {
-               ntfs_warning(vol->sb, "Error allocating page buffers. "
-                               "Redirtying page so we try again later.");
-               /*
-                * Put the page back on mapping->dirty_pages, but leave its
-                * buffer's dirty state as-is.
-                */
-               redirty_page_for_writepage(wbc, page);
-               unlock_page(page);
-               return 0;
-       }
+       BUG_ON(!bh);
 
        /* NOTE: Different naming scheme to ntfs_read_block()! */
 
@@ -910,7 +914,6 @@ static int ntfs_write_mst_block(struct page *page,
        sync = (wbc->sync_mode == WB_SYNC_ALL);
 
        /* Make sure we have mapped buffers. */
-       BUG_ON(!page_has_buffers(page));
        bh = head = page_buffers(page);
        BUG_ON(!bh);
 
@@ -2397,6 +2400,7 @@ void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs) {
                        buffers_to_free = bh;
        }
        bh = head = page_buffers(page);
+       BUG_ON(!bh);
        do {
                bh_ofs = bh_offset(bh);
                if (bh_ofs + bh_size <= ofs)