ocfs2: Read from an unwritten extent returns zeros

[powerpc.git] / fs / ocfs2 / alloc.c

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index 0eab0d3..412a288 100644 (file)
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -3487,6 +3487,7 @@ static int ocfs2_grab_eof_pages(struct inode *inode, loff_t isize, struct page *
 {
        int i, numpages = 0, ret = 0;
        unsigned int csize = OCFS2_SB(inode->i_sb)->s_clustersize;
+       unsigned int ext_flags;
        struct super_block *sb = inode->i_sb;
        struct address_space *mapping = inode->i_mapping;
        unsigned long index;
@@ -3499,7 +3500,7 @@ static int ocfs2_grab_eof_pages(struct inode *inode, loff_t isize, struct page *
                goto out;
 
        ret = ocfs2_extent_map_get_blocks(inode, isize >> sb->s_blocksize_bits,
-                                         phys, NULL);
+                                         phys, NULL, &ext_flags);
        if (ret) {
                mlog_errno(ret);
                goto out;
@@ -3509,6 +3510,11 @@ static int ocfs2_grab_eof_pages(struct inode *inode, loff_t isize, struct page *
        if (*phys == 0)
                goto out;
 
+       /* Tail is marked as unwritten, we can count on write to zero
+        * in that case. */
+       if (ext_flags & OCFS2_EXT_UNWRITTEN)
+               goto out;
+
        next_cluster_bytes = ocfs2_align_bytes_to_clusters(inode->i_sb, isize);
        index = isize >> PAGE_CACHE_SHIFT;
        do {
@@ -3579,9 +3585,6 @@ int ocfs2_zero_tail_for_truncate(struct inode *inode, handle_t *handle,
                goto out;
        }
 
-       /*
-        * Truncate on an i_size boundary - nothing more to do.
-        */
        if (numpages == 0)
                goto out;