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@suse.cz>
---
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 @@ ...
