Commit 94aca682 authored by David Howells's avatar David Howells Committed by Jens Axboe
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ocfs2: Provide a splice-read wrapper 



Provide a splice_read wrapper for ocfs2.  This emits trace lines and does
an atime lock/update before calling filemap_splice_read().  Splicing from
direct I/O is handled by the caller.

A couple of new tracepoints are added for this purpose.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Reviewed-by: default avatarJoseph Qi <joseph.qi@linux.alibaba.com>
cc: Christoph Hellwig <hch@lst.de>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Jens Axboe <axboe@kernel.dk>
cc: Mark Fasheh <mark@fasheh.com>
cc: Joel Becker <jlbec@evilplan.org>
cc: ocfs2-devel@oss.oracle.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-block@vger.kernel.org
cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/20230522135018.2742245-23-dhowells@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 51494398

fs/ocfs2/file.c

+39 −2
Original line number Diff line number Diff line
@@ -2552,7 +2552,7 @@ static ssize_t ocfs2_file_read_iter(struct kiocb *iocb, 
	 *

	 * Take and drop the meta data lock to update inode fields

	 * like i_size. This allows the checks down below

	 * generic_file_read_iter() a chance of actually working.

	 * copy_splice_read() a chance of actually working.

	 */

	ret = ocfs2_inode_lock_atime(inode, filp->f_path.mnt, &lock_level,

				     !nowait);
@@ -2581,6 +2581,43 @@ static ssize_t ocfs2_file_read_iter(struct kiocb *iocb, 
	return ret;

}



static ssize_t ocfs2_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 = 0;

	int lock_level = 0;



	trace_ocfs2_file_splice_read(inode, in, in->f_path.dentry,

				     (unsigned long long)OCFS2_I(inode)->ip_blkno,

				     in->f_path.dentry->d_name.len,

				     in->f_path.dentry->d_name.name,

				     flags);



	/*

	 * We're fine letting folks race truncates and extending writes with

	 * read across the cluster, just like they can locally.  Hence no

	 * rw_lock during read.

	 *

	 * Take and drop the meta data lock to update inode fields like i_size.

	 * This allows the checks down below filemap_splice_read() a chance of

	 * actually working.

	 */

	ret = ocfs2_inode_lock_atime(inode, in->f_path.mnt, &lock_level, 1);

	if (ret < 0) {

		if (ret != -EAGAIN)

			mlog_errno(ret);

		goto bail;

	}

	ocfs2_inode_unlock(inode, lock_level);



	ret = filemap_splice_read(in, ppos, pipe, len, flags);

	trace_filemap_splice_read_ret(ret);

bail:

	return ret;

}



/* Refer generic_file_llseek_unlocked() */

static loff_t ocfs2_file_llseek(struct file *file, loff_t offset, int whence)

{
@@ -2744,7 +2781,7 @@ const struct file_operations ocfs2_fops = { 
#endif

	.lock		= ocfs2_lock,

	.flock		= ocfs2_flock,

	.splice_read	= generic_file_splice_read,

	.splice_read	= ocfs2_file_splice_read,

	.splice_write	= iter_file_splice_write,

	.fallocate	= ocfs2_fallocate,

	.remap_file_range = ocfs2_remap_file_range,

fs/ocfs2/ocfs2_trace.h

+3 −0
Original line number Diff line number Diff line
@@ -1319,6 +1319,8 @@ DEFINE_OCFS2_FILE_OPS(ocfs2_file_splice_write); 


DEFINE_OCFS2_FILE_OPS(ocfs2_file_read_iter);



DEFINE_OCFS2_FILE_OPS(ocfs2_file_splice_read);



DEFINE_OCFS2_ULL_ULL_ULL_EVENT(ocfs2_truncate_file);



DEFINE_OCFS2_ULL_ULL_EVENT(ocfs2_truncate_file_error);
@@ -1470,6 +1472,7 @@ TRACE_EVENT(ocfs2_prepare_inode_for_write, 
);



DEFINE_OCFS2_INT_EVENT(generic_file_read_iter_ret);

DEFINE_OCFS2_INT_EVENT(filemap_splice_read_ret);



/* End of trace events for fs/ocfs2/file.c. */