On Thu, Mar 09 2017, Jeff Layton wrote:
> Currently we don't clear the address space error when there is a -EIO
> error on fsynci, due to writeback initiation failure. If writes fail
> with -EIO and the mapping is flagged with an AS_EIO or AS_ENOSPC error,
> then we can end up returning errors on two fsync calls, even when a
> write between them succeeded (or there was no write).
>
> Ensure that we also clear out any mapping errors when initiating
> writeback fails with -EIO in filemap_write_and_wait and
> filemap_write_and_wait_range.
This change appears to assume that filemap_write_and_wait* is only
called from fsync() (or similar) and the return status is always
checked.
A __must_check annotation might be helpful.
It would catch v9_fs_file_lock(), afs_setattr() and others.
While I think your change is probably heading in the right direction,
there seem to be some loose ends still.
Thanks,
NeilBrown
>
> Suggested-by: Jan Kara <jack@xxxxxxx>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> mm/filemap.c | 20 ++++++++++++++++++--
> 1 file changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 1694623a6289..fc123b9833e1 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -488,7 +488,7 @@ EXPORT_SYMBOL(filemap_fdatawait);
>
> int filemap_write_and_wait(struct address_space *mapping)
> {
> - int err = 0;
> + int err;
>
> if ((!dax_mapping(mapping) && mapping->nrpages) ||
> (dax_mapping(mapping) && mapping->nrexceptional)) {
> @@ -499,10 +499,18 @@ int filemap_write_and_wait(struct address_space *mapping)
> * But the -EIO is special case, it may indicate the worst
> * thing (e.g. bug) happened, so we avoid waiting for it.
> */
> - if (err != -EIO) {
> + if (likely(err != -EIO)) {
> int err2 = filemap_fdatawait(mapping);
> if (!err)
> err = err2;
> + } else {
> + /*
> + * Clear the error in the address space since we're
> + * returning an error here. -EIO takes precedence over
> + * everything else though, so we can just discard
> + * the return here.
> + */
> + filemap_check_errors(mapping);
> }
> } else {
> err = filemap_check_errors(mapping);
> @@ -537,6 +545,14 @@ int filemap_write_and_wait_range(struct address_space *mapping,
> lstart, lend);
> if (!err)
> err = err2;
> + } else {
> + /*
> + * Clear the error in the address space since we're
> + * returning an error here. -EIO takes precedence over
> + * everything else though, so we can just discard
> + * the return here.
> + */
> + filemap_check_errors(mapping);
> }
> } else {
> err = filemap_check_errors(mapping);
> --
> 2.9.3
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