orangefs: Provide a splice-read wrapper

Provide a splice_read wrapper for ocfs2.  This increments the read stats
and then locks the inode across the call to filemap_splice_read() and a
revalidation of the mapping.  Splicing from direct I/O is done by the
caller.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Christoph Hellwig <hch@lst.de>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Jens Axboe <axboe@kernel.dk>
cc: Mike Marshall <hubcap@omnibond.com>
cc: Martin Brandenburg <martin@omnibond.com>
cc: devel@lists.orangefs.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-block@vger.kernel.org
cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/20230522135018.2742245-24-dhowells@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/orangefs/file.c b/fs/orangefs/file.c
index 1a4301a..d683722 100644 (file)
--- a/fs/orangefs/file.c
+++ b/fs/orangefs/file.c
@@ -337,6 +337,26 @@ out:
        return ret;
 }
 
+static ssize_t orangefs_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);
+       ssize_t ret;
+
+       orangefs_stats.reads++;
+
+       down_read(&inode->i_rwsem);
+       ret = orangefs_revalidate_mapping(inode);
+       if (ret)
+               goto out;
+
+       ret = filemap_splice_read(in, ppos, pipe, len, flags);
+out:
+       up_read(&inode->i_rwsem);
+       return ret;
+}
+
 static ssize_t orangefs_file_write_iter(struct kiocb *iocb,
     struct iov_iter *iter)
 {
@@ -556,7 +576,7 @@ const struct file_operations orangefs_file_operations = {
        .lock           = orangefs_lock,
        .mmap           = orangefs_file_mmap,
        .open           = generic_file_open,
-       .splice_read    = generic_file_splice_read,
+       .splice_read    = orangefs_file_splice_read,
        .splice_write   = iter_file_splice_write,
        .flush          = orangefs_flush,
        .release        = orangefs_file_release,