GFS2: fix block allocation check for fallocate

[pandora-kernel.git] / fs / gfs2 / file.c

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 2878481..4074b95 100644 (file)
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -622,8 +622,7 @@ static void empty_write_end(struct page *page, unsigned from,
 {
        struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 
-       page_zero_new_buffers(page, from, to);
-       flush_dcache_page(page);
+       zero_user(page, from, to-from);
        mark_page_accessed(page);
 
        if (!gfs2_is_writeback(ip))
@@ -632,36 +631,43 @@ static void empty_write_end(struct page *page, unsigned from,
        block_commit_write(page, from, to);
 }
 
-static int write_empty_blocks(struct page *page, unsigned from, unsigned to)
+static int needs_empty_write(sector_t block, struct inode *inode)
 {
-       unsigned start, end, next;
-       struct buffer_head *bh, *head;
        int error;
+       struct buffer_head bh_map = { .b_state = 0, .b_blocknr = 0 };
 
-       if (!page_has_buffers(page)) {
-               error = __block_write_begin(page, from, to - from, gfs2_block_map);
-               if (unlikely(error))
-                       return error;
+       bh_map.b_size = 1 << inode->i_blkbits;
+       error = gfs2_block_map(inode, block, &bh_map, 0);
+       if (unlikely(error))
+               return error;
+       return !buffer_mapped(&bh_map);
+}
 
-               empty_write_end(page, from, to);
-               return 0;
-       }
+static int write_empty_blocks(struct page *page, unsigned from, unsigned to)
+{
+       struct inode *inode = page->mapping->host;
+       unsigned start, end, next, blksize;
+       sector_t block = page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
+       int ret;
 
-       bh = head = page_buffers(page);
+       blksize = 1 << inode->i_blkbits;
        next = end = 0;
        while (next < from) {
-               next += bh->b_size;
-               bh = bh->b_this_page;
+               next += blksize;
+               block++;
        }
        start = next;
        do {
-               next += bh->b_size;
-               if (buffer_mapped(bh)) {
+               next += blksize;
+               ret = needs_empty_write(block, inode);
+               if (unlikely(ret < 0))
+                       return ret;
+               if (ret == 0) {
                        if (end) {
-                               error = __block_write_begin(page, start, end - start,
-                                                           gfs2_block_map);
-                               if (unlikely(error))
-                                       return error;
+                               ret = __block_write_begin(page, start, end - start,
+                                                         gfs2_block_map);
+                               if (unlikely(ret))
+                                       return ret;
                                empty_write_end(page, start, end);
                                end = 0;
                        }
@@ -669,13 +675,13 @@ static int write_empty_blocks(struct page *page, unsigned from, unsigned to)
                }
                else
                        end = next;
-               bh = bh->b_this_page;
+               block++;
        } while (next < to);
 
        if (end) {
-               error = __block_write_begin(page, start, end - start, gfs2_block_map);
-               if (unlikely(error))
-                       return error;
+               ret = __block_write_begin(page, start, end - start, gfs2_block_map);
+               if (unlikely(ret))
+                       return ret;
                empty_write_end(page, start, end);
        }