ocfs2: zero tail of sparse files on truncate

Since we don't zero on extend anymore, truncate needs to be fixed up to zero
the part of a file between i_size and and end of it's cluster. Otherwise a
subsequent extend could expose bad data.

This introduced a new helper, which can be used in ocfs2_write().

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

1 files changed, 15 insertions, 19 deletions

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index acf8f0006725..605c82a93f01 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -308,13 +308,13 @@ int ocfs2_prepare_write_nolock(struct inode *inode, struct page *page,
  * functionality yet, but IMHO it's better to cut and paste the whole
  * thing so we can avoid introducing our own bugs (and easily pick up
  * their fixes when they happen) --Mark */
-static int walk_page_buffers(   handle_t *handle,
-                                struct buffer_head *head,
-                                unsigned from,
-                                unsigned to,
-                                int *partial,
-                                int (*fn)(      handle_t *handle,
-                                                struct buffer_head *bh))
+int walk_page_buffers(  handle_t *handle,
+                        struct buffer_head *head,
+                        unsigned from,
+                        unsigned to,
+                        int *partial,
+                        int (*fn)(      handle_t *handle,
+                                        struct buffer_head *bh))
 {
         struct buffer_head *bh;
         unsigned block_start, block_end;
@@ -654,9 +654,9 @@ static void ocfs2_clear_page_regions(struct page *page,
  *
  * This will also skip zeroing, which is handled externally.
  */
-static int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno,
-                                 struct inode *inode, unsigned int from,
-                                 unsigned int to, int new)
+int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno,
+                          struct inode *inode, unsigned int from,
+                          unsigned int to, int new)
 {
         int ret = 0;
         struct buffer_head *head, *bh, *wait[2], **wait_bh = wait;
@@ -675,8 +675,7 @@ static int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno,
                  * Ignore blocks outside of our i/o range -
                  * they may belong to unallocated clusters.
                  */
-                if (block_start >= to ||
-                    (block_start + bsize) <= from) {
+                if (block_start >= to || block_end <= from) {
                         if (PageUptodate(page))
                                 set_buffer_uptodate(bh);
                         continue;
@@ -971,7 +970,6 @@ static ssize_t ocfs2_write(struct file *file, u32 phys, handle_t *handle,
         u64 v_blkno, p_blkno;
         struct address_space *mapping = file->f_mapping;
         struct inode *inode = mapping->host;
-        unsigned int cbits = OCFS2_SB(inode->i_sb)->s_clustersize_bits;
         unsigned long index, start;
         struct page **cpages;
 
@@ -979,13 +977,11 @@ static ssize_t ocfs2_write(struct file *file, u32 phys, handle_t *handle,
 
         /*
          * Figure out how many pages we'll be manipulating here. For
-         * non-allocating write, or any writes where cluster size is
-         * less than page size, we only need one page. Otherwise,
-         * allocating writes of cluster size larger than page size
-         * need cluster size pages.
+         * non allocating write, we just change the one
+         * page. Otherwise, we'll need a whole clusters worth.
          */
-        if (new && !wc->w_large_pages)
-                numpages = (1 << cbits) / PAGE_SIZE;
+        if (new)
+                numpages = ocfs2_pages_per_cluster(inode->i_sb);
 
         cpages = kzalloc(sizeof(*cpages) * numpages, GFP_NOFS);
         if (!cpages) {