From: David Howells <dhowells@redhat.com>
To: Jens Axboe <axboe@kernel.dk>, Al Viro <viro@zeniv.linux.org.uk>,
Christoph Hellwig <hch@infradead.org>
Cc: David Howells <dhowells@redhat.com>,
Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
Jeff Layton <jlayton@kernel.org>,
David Hildenbrand <david@redhat.com>,
Jason Gunthorpe <jgg@nvidia.com>,
Logan Gunthorpe <logang@deltatee.com>,
Hillf Danton <hdanton@sina.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Christoph Hellwig <hch@lst.de>,
John Hubbard <jhubbard@nvidia.com>,
Miklos Szeredi <miklos@szeredi.hu>,
linux-unionfs@vger.kernel.org
Subject: [PATCH v17 04/14] overlayfs: Implement splice-read
Date: Wed, 8 Mar 2023 16:52:41 +0000 [thread overview]
Message-ID: <20230308165251.2078898-5-dhowells@redhat.com> (raw)
In-Reply-To: <20230308165251.2078898-1-dhowells@redhat.com>
Implement splice-read for overlayfs by passing the request down a layer
rather than going through generic_file_splice_read() which is going to be
changed to assume that ->read_folio() is present on buffered files.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Christoph Hellwig <hch@lst.de>
cc: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: John Hubbard <jhubbard@nvidia.com>
cc: David Hildenbrand <david@redhat.com>
cc: Matthew Wilcox <willy@infradead.org>
cc: Miklos Szeredi <miklos@szeredi.hu>
cc: linux-unionfs@vger.kernel.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
---
Notes:
ver #17)
- Use vfs_splice_read() helper rather than open-coding checks.
ver #15)
- Remove redundant FMODE_CAN_ODIRECT check on real file.
- Do rw_verify_area() on the real file, not the overlay file.
- Fix a file leak.
fs/overlayfs/file.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 7c04f033aadd..86197882ff35 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -419,6 +419,27 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
return ret;
}
+static ssize_t ovl_splice_read(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe, size_t len,
+ unsigned int flags)
+{
+ const struct cred *old_cred;
+ struct fd real;
+ ssize_t ret;
+
+ ret = ovl_real_fdget(in, &real);
+ if (ret)
+ return ret;
+
+ old_cred = ovl_override_creds(file_inode(in)->i_sb);
+ ret = vfs_splice_read(real.file, ppos, pipe, len, flags);
+ revert_creds(old_cred);
+ ovl_file_accessed(in);
+
+ fdput(real);
+ return ret;
+}
+
/*
* Calling iter_file_splice_write() directly from overlay's f_op may deadlock
* due to lock order inversion between pipe->mutex in iter_file_splice_write()
@@ -695,7 +716,7 @@ const struct file_operations ovl_file_operations = {
.fallocate = ovl_fallocate,
.fadvise = ovl_fadvise,
.flush = ovl_flush,
- .splice_read = generic_file_splice_read,
+ .splice_read = ovl_splice_read,
.splice_write = ovl_splice_write,
.copy_file_range = ovl_copy_file_range,
next prev parent reply other threads:[~2023-03-08 16:54 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230308165251.2078898-1-dhowells@redhat.com>
2023-03-08 16:52 ` [PATCH v17 02/14] splice: Make do_splice_to() generic and export it David Howells
2023-03-14 17:31 ` Christoph Hellwig
2023-03-14 21:15 ` David Howells
2023-03-15 16:34 ` [RFC PATCH] splice: Convert longs and some ints into ssize_t David Howells
2023-03-08 16:52 ` David Howells [this message]
2023-03-08 16:52 ` [PATCH v17 05/14] coda: Implement splice-read David Howells
2023-03-13 13:28 ` Jan Harkes
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