block_prepare_write() can dirty freshly created buffer. This is a problem
for data=journal mode because data buffers shouldn't be dirty unless they
are undergoing checkpoint. So we have to tweak get_block function for
data=journal mode to catch the case when block_prepare_write would dirty
the buffer, do the work instead of block_prepare_write, and properly handle
dirty buffer as data=journal mode requires it.
It might be cleaner to avoid using block_prepare_write() for data=journal
mode writes but that would require us to duplicate most of the function
which isn't nice either...
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/ext3/inode.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++-------
1 files changed, 48 insertions(+), 8 deletions(-)
diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
index ea33bdf..2b61cc4 100644
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -993,6 +993,43 @@ out:
return ret;
}
+static int ext3_journalled_get_block(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh, int create)
+{
+ handle_t *handle = ext3_journal_current_handle();
+ int ret;
+
+ /* This function should ever be used only for real buffers */
+ BUG_ON(!bh->b_page);
+
+ ret = ext3_get_blocks_handle(handle, inode, iblock, 1, bh, create);
+ if (ret > 0) {
+ if (buffer_new(bh)) {
+ struct page *page = bh->b_page;
+
+ /*
+ * This is a terrible hack to avoid block_prepare_write
+ * marking our buffer as dirty
+ */
+ if (PageUptodate(page)) {
+ ret = ext3_journal_get_write_access(handle, bh);
+ if (ret < 0)
+ goto out;
+ unmap_underlying_metadata(bh->b_bdev,
+ bh->b_blocknr);
+ clear_buffer_new(bh);
+ set_buffer_uptodate(bh);
+ ret = ext3_journal_dirty_metadata(handle, bh);
+ if (ret < 0)
+ goto out;
+ }
+ }
+ ret = 0;
+ }
+out:
+ return ret;
+}
+
int ext3_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
u64 start, u64 len)
{
@@ -1196,15 +1233,18 @@ retry:
ret = PTR_ERR(handle);
goto out;
}
- ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
- ext3_get_block);
- if (ret)
- goto write_begin_failed;
-
if (ext3_should_journal_data(inode)) {
- ret = walk_page_buffers(handle, page_buffers(page),
- from, to, NULL, do_journal_get_write_access);
+ ret = block_write_begin(file, mapping, pos, len, flags, pagep,
+ fsdata, ext3_journalled_get_block);
+ if (ret)
+ goto write_begin_failed;
+ ret = walk_page_buffers(handle, page_buffers(page), from, to,
+ NULL, do_journal_get_write_access);
+ } else {
+ ret = block_write_begin(file, mapping, pos, len, flags, pagep,
+ fsdata, ext3_get_block);
}
+
write_begin_failed:
if (ret) {
/*
@@ -1668,7 +1708,7 @@ static int ext3_journalled_writepage(struct page *page,
*/
ClearPageChecked(page);
ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
- ext3_get_block);
+ ext3_journalled_get_block);
if (ret != 0) {
ext3_journal_stop(handle);
goto out_unlock;
--
1.6.4.2
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