On 5/22/23 22:50, David Howells wrote:
> Provide a splice_read wrapper for zonefs. This does some checks before
> proceeding and locks the inode across the call to filemap_splice_read() and
> a size check in case of truncation. Splicing from direct I/O is handled by
> the caller.
>
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> cc: Christoph Hellwig <hch@xxxxxx>
> cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> cc: Jens Axboe <axboe@xxxxxxxxx>
> cc: Darrick J. Wong <djwong@xxxxxxxxxx>
> cc: linux-xfs@xxxxxxxxxxxxxxx
> cc: linux-fsdevel@xxxxxxxxxxxxxxx
> cc: linux-block@xxxxxxxxxxxxxxx
> cc: linux-mm@xxxxxxxxx
One comment below but otherwise looks OK.
Acked-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
> ---
> fs/zonefs/file.c | 40 +++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 39 insertions(+), 1 deletion(-)
>
> diff --git a/fs/zonefs/file.c b/fs/zonefs/file.c
> index 132f01d3461f..65d4c4fe6364 100644
> --- a/fs/zonefs/file.c
> +++ b/fs/zonefs/file.c
> @@ -752,6 +752,44 @@ static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
> return ret;
> }
>
> +static ssize_t zonefs_file_splice_read(struct file *in, loff_t *ppos,
> + struct pipe_inode_info *pipe,
> + size_t len, unsigned int flags)
> +{
> + struct inode *inode = file_inode(in);
> + struct zonefs_inode_info *zi = ZONEFS_I(inode);
> + struct zonefs_zone *z = zonefs_inode_zone(inode);
> + loff_t isize;
> + ssize_t ret = 0;
> +
> + /* Offline zones cannot be read */
> + if (unlikely(IS_IMMUTABLE(inode) && !(inode->i_mode & 0777)))
> + return -EPERM;
> +
> + if (*ppos >= z->z_capacity)
> + return 0;
> +
> + inode_lock_shared(inode);
> +
> + /* Limit read operations to written data */
> + mutex_lock(&zi->i_truncate_mutex);
> + isize = i_size_read(inode);
> + if (*ppos >= isize)
> + len = 0;
> + else
> + len = min_t(loff_t, len, isize - *ppos);
> + mutex_unlock(&zi->i_truncate_mutex);
> +
> + if (len > 0) {
> + ret = filemap_splice_read(in, ppos, pipe, len, flags);
> + if (ret == -EIO)
Is -EIO the only error that filemap_splice_read() may return ? There are other
IO error codes that we could get from the block layer, e.g. -ETIMEDOUT etc. So
"if (ret < 0)" may be better here ?
> + zonefs_io_error(inode, false);
> + }
> +
> + inode_unlock_shared(inode);
> + return ret;
> +}
> +
> /*
> * Write open accounting is done only for sequential files.
> */
> @@ -896,7 +934,7 @@ const struct file_operations zonefs_file_operations = {
> .llseek = zonefs_file_llseek,
> .read_iter = zonefs_file_read_iter,
> .write_iter = zonefs_file_write_iter,
> - .splice_read = generic_file_splice_read,
> + .splice_read = zonefs_file_splice_read,
> .splice_write = iter_file_splice_write,
> .iopoll = iocb_bio_iopoll,
> };
>
--
Damien Le Moal
Western Digital Research
