On Fri, 2020-07-31 at 13:46 -0400, Scott Mayhew wrote:
> nfs_wb_all() calls filemap_write_and_wait(), which uses
> filemap_check_errors() to determine the error to return.
> filemap_check_errors() only looks at the mapping->flags and will
> therefore only return either -ENOSPC or -EIO. To ensure that the
> correct error is returned on close(), nfs{,4}_file_flush() should
> call
> file_check_and_advance_wb_err() which looks at the errseq value in
> mapping->wb_err.
>
> Fixes: 6fbda89b257f ("NFS: Replace custom error reporting mechanism
> with
> generic one")
> Signed-off-by: Scott Mayhew <smayhew@xxxxxxxxxx>
> ---
> fs/nfs/file.c | 3 ++-
> fs/nfs/nfs4file.c | 3 ++-
> 2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/fs/nfs/file.c b/fs/nfs/file.c
> index f96367a2463e..eeef6580052f 100644
> --- a/fs/nfs/file.c
> +++ b/fs/nfs/file.c
> @@ -148,7 +148,8 @@ nfs_file_flush(struct file *file, fl_owner_t id)
> return 0;
>
> /* Flush writes to the server and return any errors */
> - return nfs_wb_all(inode);
> + nfs_wb_all(inode);
> + return file_check_and_advance_wb_err(file);
> }
>
> ssize_t
> diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
> index 8e5d6223ddd3..77bf9c12734c 100644
> --- a/fs/nfs/nfs4file.c
> +++ b/fs/nfs/nfs4file.c
> @@ -125,7 +125,8 @@ nfs4_file_flush(struct file *file, fl_owner_t id)
> return filemap_fdatawrite(file->f_mapping);
>
> /* Flush writes to the server and return any errors */
> - return nfs_wb_all(inode);
> + nfs_wb_all(inode);
> + return file_check_and_advance_wb_err(file);
> }
>
> #ifdef CONFIG_NFS_V4_2
I don't think this one is correct. The contract with POSIX is that we
always deliver the error on fsync(). If we call
file_check_and_advance_wb_err() here in nfs_file_flush(), then that
means we eat the error before it can get delivered to fsync().
--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@xxxxxxxxxxxxxxx
