[PATCH] revert "retries in ext4_prepare_write() violate ordering requirements"

Revert b46be05004abb419e303e66e143eed9f8a6e9f3f.  Same reasoning as for ext3.

Cc: Kirill Korotaev <dev@openvz.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ken Chen <kenneth.w.chen@intel.com>
Cc: Andrey Savochkin <saw@sw.ru>
Cc: <linux-ext4@vger.kernel.org>
Cc: Dmitriy Monakhov <dmonakhov@openvz.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 10 insertions, 75 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index fbff4b9e122a..810b6d6474bf 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1147,102 +1147,37 @@ static int do_journal_get_write_access(handle_t *handle,
         return ext4_journal_get_write_access(handle, bh);
 }
 
-/*
- * The idea of this helper function is following:
- * if prepare_write has allocated some blocks, but not all of them, the
- * transaction must include the content of the newly allocated blocks.
- * This content is expected to be set to zeroes by block_prepare_write().
- * 2006/10/14  SAW
- */
-static int ext4_prepare_failure(struct file *file, struct page *page,
-                                unsigned from, unsigned to)
-{
-        struct address_space *mapping;
-        struct buffer_head *bh, *head, *next;
-        unsigned block_start, block_end;
-        unsigned blocksize;
-        int ret;
-        handle_t *handle = ext4_journal_current_handle();
-
-        mapping = page->mapping;
-        if (ext4_should_writeback_data(mapping->host)) {
-                /* optimization: no constraints about data */
-skip:
-                return ext4_journal_stop(handle);
-        }
-
-        head = page_buffers(page);
-        blocksize = head->b_size;
-        for (   bh = head, block_start = 0;
-                bh != head || !block_start;
-                block_start = block_end, bh = next)
-        {
-                next = bh->b_this_page;
-                block_end = block_start + blocksize;
-                if (block_end <= from)
-                        continue;
-                if (block_start >= to) {
-                        block_start = to;
-                        break;
-                }
-                if (!buffer_mapped(bh))
-                /* prepare_write failed on this bh */
-                        break;
-                if (ext4_should_journal_data(mapping->host)) {
-                        ret = do_journal_get_write_access(handle, bh);
-                        if (ret) {
-                                ext4_journal_stop(handle);
-                                return ret;
-                        }
-                }
-        /*
-         * block_start here becomes the first block where the current iteration
-         * of prepare_write failed.
-         */
-        }
-        if (block_start <= from)
-                goto skip;
-
-        /* commit allocated and zeroed buffers */
-        return mapping->a_ops->commit_write(file, page, from, block_start);
-}
-
 static int ext4_prepare_write(struct file *file, struct page *page,
                               unsigned from, unsigned to)
 {
         struct inode *inode = page->mapping->host;
-        int ret, ret2;
-        int needed_blocks = ext4_writepage_trans_blocks(inode);
+        int ret, needed_blocks = ext4_writepage_trans_blocks(inode);
         handle_t *handle;
         int retries = 0;
 
 retry:
         handle = ext4_journal_start(inode, needed_blocks);
-        if (IS_ERR(handle))
-                return PTR_ERR(handle);
+        if (IS_ERR(handle)) {
+                ret = PTR_ERR(handle);
+                goto out;
+        }
         if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
                 ret = nobh_prepare_write(page, from, to, ext4_get_block);
         else
                 ret = block_prepare_write(page, from, to, ext4_get_block);
         if (ret)
-                goto failure;
+                goto prepare_write_failed;
 
         if (ext4_should_journal_data(inode)) {
                 ret = walk_page_buffers(handle, page_buffers(page),
                                 from, to, NULL, do_journal_get_write_access);
-                if (ret)
-                        /* fatal error, just put the handle and return */
-                        ext4_journal_stop(handle);
         }
-        return ret;
-
-failure:
-        ret2 = ext4_prepare_failure(file, page, from, to);
-        if (ret2 < 0)
-                return ret2;
+prepare_write_failed:
+        if (ret)
+                ext4_journal_stop(handle);
         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
                 goto retry;
-        /* retry number exceeded, or other error like -EDQUOT */
+out:
         return ret;
 }