[patch 29/31] revert "retries in ext4_prepare_write() violate ordering requirements"

Greg KH
2007-04-11T22:57:01Z

[-- Attachment #1: revert-retries-in-ext4_prepare_write-violate-ordering-requirements.patch --]
[-- Type: text/plain, Size: 3885 bytes --]

-stable review patch. If anyone has any objections, please let us know.

------------------

From: Andrew Morton <akpm@linux-foundation.org>

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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
fs/ext4/inode.c | 85 ++++++--------------------------------------------------
1 file changed, 10 insertions(+), 75 deletions(-)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1147,102 +1147,37 @@ static int do_journal_get_write_access(h
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;
}

--