ext4: Fix mmap/truncate race when blocksize < pagesize && delayed allocation

[karo-tx-linux.git] / fs / ext4 / inode.c

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index b87b68cd32413a76654b747cf4d81f739a0e7881..1275f34589c73cf27526253da8064b2471274a94 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2305,15 +2305,9 @@ flush_it:
        return;
 }
 
-static int ext4_bh_unmapped_or_delay(handle_t *handle, struct buffer_head *bh)
+static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
 {
-       /*
-        * unmapped buffer is possible for holes.
-        * delay buffer is possible with delayed allocation.
-        * We also need to consider unwritten buffer as unmapped.
-        */
-       return (!buffer_mapped(bh) || buffer_delay(bh) ||
-                               buffer_unwritten(bh)) && buffer_dirty(bh);
+       return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
 }
 
 /*
@@ -2400,7 +2394,7 @@ static int __mpage_da_writepage(struct page *page,
                         * Otherwise we won't make progress
                         * with the page in ext4_da_writepage
                         */
-                       if (ext4_bh_unmapped_or_delay(NULL, bh)) {
+                       if (ext4_bh_delay_or_unwritten(NULL, bh)) {
                                mpage_add_bh_to_extent(mpd, logical,
                                                       bh->b_size,
                                                       bh->b_state);
@@ -2517,7 +2511,6 @@ static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
         * so call get_block_wrap with create = 0
         */
        ret = ext4_get_blocks(NULL, inode, iblock, max_blocks, bh_result, 0);
-       BUG_ON(create && ret == 0);
        if (ret > 0) {
                bh_result->b_size = (ret << inode->i_blkbits);
                ret = 0;
@@ -2533,7 +2526,7 @@ static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
  *   - grab_page_cache when doing write_begin (have journal handle)
  */
 static int ext4_da_writepage(struct page *page,
-                               struct writeback_control *wbc)
+                            struct writeback_control *wbc)
 {
        int ret = 0;
        loff_t size;
@@ -2551,7 +2544,7 @@ static int ext4_da_writepage(struct page *page,
        if (page_has_buffers(page)) {
                page_bufs = page_buffers(page);
                if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
-                                       ext4_bh_unmapped_or_delay)) {
+                                       ext4_bh_delay_or_unwritten)) {
                        /*
                         * We don't want to do  block allocation
                         * So redirty the page and return
@@ -2584,7 +2577,7 @@ static int ext4_da_writepage(struct page *page,
                        page_bufs = page_buffers(page);
                        /* check whether all are mapped and non delay */
                        if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
-                                               ext4_bh_unmapped_or_delay)) {
+                                               ext4_bh_delay_or_unwritten)) {
                                redirty_page_for_writepage(wbc, page);
                                unlock_page(page);
                                return 0;
@@ -3232,7 +3225,7 @@ static int ext4_normal_writepage(struct page *page,
                 * happily proceed with mapping them and writing the page.
                 */
                BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
-                                       ext4_bh_unmapped_or_delay));
+                                       ext4_bh_delay_or_unwritten));
        }
 
        if (!ext4_journal_current_handle())
@@ -3322,7 +3315,7 @@ static int ext4_journalled_writepage(struct page *page,
                 * happily proceed with mapping them and writing the page.
                 */
                BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
-                                       ext4_bh_unmapped_or_delay));
+                                       ext4_bh_delay_or_unwritten));
        }
 
        if (ext4_journal_current_handle())