[v8,18/18] btrfs: minimal conversion to errseq_t writeback error reporting on fsync

Message ID 20170629131954.28733-19-jlayton@kernel.org
State Not Applicable
Headers show

Commit Message

Jeff Layton June 29, 2017, 1:19 p.m.
From: Jeff Layton <jlayton@redhat.com>

Just check and advance the errseq_t in the file before returning.
Internal callers of filemap_* functions are left as-is.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
 fs/btrfs/file.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

Comments

Christoph Hellwig June 29, 2017, 2:17 p.m. | #1
On Thu, Jun 29, 2017 at 09:19:54AM -0400, jlayton@kernel.org wrote:
> From: Jeff Layton <jlayton@redhat.com>
> 
> Just check and advance the errseq_t in the file before returning.
> Internal callers of filemap_* functions are left as-is.
> 
> Signed-off-by: Jeff Layton <jlayton@redhat.com>
> ---
>  fs/btrfs/file.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
> index da1096eb1a40..1f57e1a523d9 100644
> --- a/fs/btrfs/file.c
> +++ b/fs/btrfs/file.c
> @@ -2011,7 +2011,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
>  	struct btrfs_root *root = BTRFS_I(inode)->root;
>  	struct btrfs_trans_handle *trans;
>  	struct btrfs_log_ctx ctx;
> -	int ret = 0;
> +	int ret = 0, err;
>  	bool full_sync = 0;
>  	u64 len;
>  
> @@ -2030,7 +2030,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
>  	 */
>  	ret = start_ordered_ops(inode, start, end);
>  	if (ret)
> -		return ret;
> +		goto out;
>  
>  	inode_lock(inode);
>  	atomic_inc(&root->log_batch);
> @@ -2227,6 +2227,9 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
>  		ret = btrfs_end_transaction(trans);
>  	}
>  out:
> +	err = file_check_and_advance_wb_err(file);
> +	if (!ret)
> +		ret = err;
>  	return ret > 0 ? -EIO : ret;

This means that we'll lose the exact error returned from
start_ordered_ops.  Beyond that I can't really provide good feedback
as the btrfs fsync code looks so much different from all the other
fs fsync code..
Jeff Layton June 29, 2017, 8:32 p.m. | #2
On Thu, 2017-06-29 at 07:17 -0700, Christoph Hellwig wrote:
> On Thu, Jun 29, 2017 at 09:19:54AM -0400, jlayton@kernel.org wrote:
> > From: Jeff Layton <jlayton@redhat.com>
> > 
> > Just check and advance the errseq_t in the file before returning.
> > Internal callers of filemap_* functions are left as-is.
> > 
> > Signed-off-by: Jeff Layton <jlayton@redhat.com>
> > ---
> >  fs/btrfs/file.c | 7 +++++--
> >  1 file changed, 5 insertions(+), 2 deletions(-)
> > 
> > diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
> > index da1096eb1a40..1f57e1a523d9 100644
> > --- a/fs/btrfs/file.c
> > +++ b/fs/btrfs/file.c
> > @@ -2011,7 +2011,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
> >  	struct btrfs_root *root = BTRFS_I(inode)->root;
> >  	struct btrfs_trans_handle *trans;
> >  	struct btrfs_log_ctx ctx;
> > -	int ret = 0;
> > +	int ret = 0, err;
> >  	bool full_sync = 0;
> >  	u64 len;
> >  
> > @@ -2030,7 +2030,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
> >  	 */
> >  	ret = start_ordered_ops(inode, start, end);
> >  	if (ret)
> > -		return ret;
> > +		goto out;
> >  
> >  	inode_lock(inode);
> >  	atomic_inc(&root->log_batch);
> > @@ -2227,6 +2227,9 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
> >  		ret = btrfs_end_transaction(trans);
> >  	}
> >  out:
> > +	err = file_check_and_advance_wb_err(file);
> > +	if (!ret)
> > +		ret = err;
> >  	return ret > 0 ? -EIO : ret;
> 
> This means that we'll lose the exact error returned from
> start_ordered_ops.  Beyond that I can't really provide good feedback
> as the btrfs fsync code looks so much different from all the other
> fs fsync code..

Well, no...we'll keep the error from start_ordered_ops if there was one.
 We just advance the cursor past any stored error in that case without
returning it.

I have another fix for this patch too: there's a call to
filemap_check_errors in this function that I think should probably use
filemap_check_wb_err instead. Fixed in my tree.

I do agree though that while this works in my testing I'd like the btrfs
guys to ACK this as I don't fully grok the btrfs fsync code at all.

Patch

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index da1096eb1a40..1f57e1a523d9 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2011,7 +2011,7 @@  int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 	struct btrfs_root *root = BTRFS_I(inode)->root;
 	struct btrfs_trans_handle *trans;
 	struct btrfs_log_ctx ctx;
-	int ret = 0;
+	int ret = 0, err;
 	bool full_sync = 0;
 	u64 len;
 
@@ -2030,7 +2030,7 @@  int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 	 */
 	ret = start_ordered_ops(inode, start, end);
 	if (ret)
-		return ret;
+		goto out;
 
 	inode_lock(inode);
 	atomic_inc(&root->log_batch);
@@ -2227,6 +2227,9 @@  int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 		ret = btrfs_end_transaction(trans);
 	}
 out:
+	err = file_check_and_advance_wb_err(file);
+	if (!ret)
+		ret = err;
 	return ret > 0 ? -EIO : ret;
 }