[v3,2/5] ext4: remove ext4_buffer_uptodate()

Commit Message

Zhang Yi June 20, 2020, 2:54 a.m. UTC

After we add async write error check in ext4_journal_get_write_access(),
we can remove the partial fix for filesystem inconsistency problem
caused by reading old data from disk, which in commit <7963e5ac9012>
"ext4: treat buffers with write errors as containing valid data" and
<cf2834a5ed57> "ext4: treat buffers contining write errors as valid in
ext4_sb_bread()".

Signed-off-by: zhangyi (F) <[e-mail]>
---
 fs/ext4/ext4.h  | 13 -------------
 fs/ext4/inode.c |  4 ++--
 fs/ext4/super.c |  2 +-
 3 files changed, 3 insertions(+), 16 deletions(-)

Comments

Theodore Ts'o Aug. 7, 2020, 5:53 p.m. UTC | #1

On Sat, Jun 20, 2020 at 10:54:24AM +0800, zhangyi (F) wrote:
> After we add async write error check in ext4_journal_get_write_access(),
> we can remove the partial fix for filesystem inconsistency problem
> caused by reading old data from disk, which in commit <7963e5ac9012>
> "ext4: treat buffers with write errors as containing valid data" and
> <cf2834a5ed57> "ext4: treat buffers contining write errors as valid in
> ext4_sb_bread()".
> 
> Signed-off-by: zhangyi (F) <[e-mail]>

I think it's better to keep these checks (in commits 2 and 3) because
ext4_error() doens't guarantee that the file system will be aborted.
For better or for worse, there are a large number of file systems
which default to errors=continue.

So if we notice that the buffer is not up to date, due to a write
error, we can avoid some (although not all) damage if we keep this
workaround.

					- Ted

Patch

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 60374eda1f51..f22940e5de5a 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3501,19 +3501,6 @@  extern const struct iomap_ops ext4_iomap_ops;
 extern const struct iomap_ops ext4_iomap_overwrite_ops;
 extern const struct iomap_ops ext4_iomap_report_ops;
 
-static inline int ext4_buffer_uptodate(struct buffer_head *bh)
-{
-	/*
-	 * If the buffer has the write error flag, we have failed
-	 * to write out data in the block.  In this  case, we don't
-	 * have to read the block because we may read the old data
-	 * successfully.
-	 */
-	if (!buffer_uptodate(bh) && buffer_write_io_error(bh))
-		set_buffer_uptodate(bh);
-	return buffer_uptodate(bh);
-}
-
 #endif	/* __KERNEL__ */
 
 #define EFSBADCRC	EBADMSG		/* Bad CRC detected */
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 40ec5c7ef0d3..f68afc5c0b2d 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -883,7 +883,7 @@  struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
 	bh = ext4_getblk(handle, inode, block, map_flags);
 	if (IS_ERR(bh))
 		return bh;
-	if (!bh || ext4_buffer_uptodate(bh))
+	if (!bh || buffer_uptodate(bh))
 		return bh;
 	ll_rw_block(REQ_OP_READ, REQ_META | REQ_PRIO, 1, &bh);
 	wait_on_buffer(bh);
@@ -910,7 +910,7 @@  int ext4_bread_batch(struct inode *inode, ext4_lblk_t block, int bh_count,
 
 	for (i = 0; i < bh_count; i++)
 		/* Note that NULL bhs[i] is valid because of holes. */
-		if (bhs[i] && !ext4_buffer_uptodate(bhs[i]))
+		if (bhs[i] && !buffer_uptodate(bhs[i]))
 			ll_rw_block(REQ_OP_READ, REQ_META | REQ_PRIO, 1,
 				    &bhs[i]);
 
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 8d3925c31b8a..513d1e270f6d 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -154,7 +154,7 @@  ext4_sb_bread(struct super_block *sb, sector_t block, int op_flags)
 
 	if (bh == NULL)
 		return ERR_PTR(-ENOMEM);
-	if (ext4_buffer_uptodate(bh))
+	if (buffer_uptodate(bh))
 		return bh;
 	ll_rw_block(REQ_OP_READ, REQ_META | op_flags, 1, &bh);
 	wait_on_buffer(bh);