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Wed, 08 Mar 2023 09:38:09 -0500 X-MC-Unique: Ie2N4SlAMG22ke7XWWlVVQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 01EBA18E0049; Wed, 8 Mar 2023 14:38:08 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5E61140C83B6; Wed, 8 Mar 2023 14:38:05 +0000 (UTC) From: David Howells To: Jens Axboe , Al Viro , Christoph Hellwig Cc: David Howells , Matthew Wilcox , Jan Kara , Jeff Layton , David Hildenbrand , Jason Gunthorpe , Logan Gunthorpe , Hillf Danton , Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Christoph Hellwig , John Hubbard , Miklos Szeredi , linux-unionfs@vger.kernel.org Subject: [PATCH v16 03/13] overlayfs: Implement splice-read Date: Wed, 8 Mar 2023 14:37:44 +0000 Message-Id: <20230308143754.1976726-4-dhowells@redhat.com> In-Reply-To: <20230308143754.1976726-1-dhowells@redhat.com> References: <20230308143754.1976726-1-dhowells@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: D713140010 X-Stat-Signature: znptih3zdcdyffxxio5psonp5k3ggfff X-HE-Tag: 1678286295-341710 X-HE-Meta: U2FsdGVkX194vBa1kU4oKfjAlPJCZMGHSDp9Xgq9NII/3FLjY/rJxXB3CYBEwmPzAB0LyPUehYhutFFpRFoMyzRWPSYOnun19AZGm4PHeVfINOu3bZ3p2bBBU3e4Ucqzx0NslRKwyV7ZkaPKRjxTrfD5zy/ulquxyvTcODzGdsKukkYG8HVUsToicBNQSpIkYx4Z/I0ybBZm21mYaOEKY4rTVowlGhxDdsF44TxtJT8Eg6C1BxSn2hsKMl5QAqLwEVK1EJi10BESv6iD4So+7DXyKkL9olrrQCiv2bKffMhd/fB8+0J7xVH0Bf5VhNudoHnWsEV5FupATcUQv8i5zCuCz/SjVYW9IPXRWxPYBTjv2eN/KV9FtPzzlRBWL8bPiT9Leqlyq1ekdIM5+zojDGp6xYbaUFOw85yGRmnk20WouHEHG0vDJPgSzN5J7xHnMyDJKW3GbUdVpIl4L7RLd5ob2uVpJPXrJoSwBP9Cqq3g0ipPmUnGC67mxWT6ou3zOyTFHAE+5AIvYKrllgZz+M3bzrELoIo6WHZUGCfO07OPl1Ll6g8aqQUQRIv6D5abyWBrnOUvVhP6/1q8bxUgIvRVC/HrfI5z9c0p6M76WwdZi0lcEm6GjgZ3+gsU0vKaxFiyTmJxrutNZjpFoCbzHqgTO8PGJfGKbbX1bXQOMx7NSIA0KTfaWnafys4C2CPdXJNpaW4Fe445wL28hwuK64noX0qjkIIf6vGoycxnHLVtzQ1R31q+GKi1l5Ff9PAEJ92WuOBzUBBPHeN8YZHz+OgfTzVvXTfSy8Y2864Up1rf3oSB6oLC41RibMM82AlDJaLDro/1AT6EwMslvyojm2qljS386ytlBg38OwAGqNSRaHp56JE9xgm5WF6xxs5RZGSgaP0YorATcXEVPgkMcgK4Xw6yycRSTlmkh0SaI01EP82QKM9VyqCsDJrRa2mloiUvs9iy7SyFOhsnQn2 mEFwR9fp rXQv7pQBTXIrbUKWjzBTYW1Dxk8Hd05PVWt4n6XkvmPPLOjtR22sDnLvGY8fi3f40bv/hp93C5HNSb8nfILdcp+W2RmM43rqgA9FQH4z0+jxEJYaFqT4LdSUmo6wg+pUSIMpFP2P7wA3/PPb9p/coxzRpIGE2YY7NEFwf2wfrZnmOdkE/XM47q95u0NC7CFzSzk0/X1GXxkPKcEmPrUdTptiIBs2+ND4oCeHmtSAC2y7rDt033tK5P6UB9WjThUAHNoKtPtZ2sHWsUbPSiJ2czNdfl301EtijmgEwlacX6i7/JueyTv7bGJ4T/RCUmrEazHsZHlu00LwC9YCgnsjLI0/hR5sKjFwCAWkogA/8ly0UrRH87vKIZM0/wfIOYx9t0PrASXYm+ZkVLmF2VjzW0TOpjubnJ2WB7hYZ5kzk33y/VcJ6HSHWOaiDPUpTdOzTDwXJ X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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 cc: Christoph Hellwig cc: Jens Axboe cc: Al Viro cc: John Hubbard cc: David Hildenbrand cc: Matthew Wilcox cc: Miklos Szeredi 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 #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 | 33 ++++++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-) diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 7c04f033aadd..a12919e9ccba 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -419,6 +419,37 @@ 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; + + ret = -EINVAL; + if (!real.file->f_op->splice_read) + goto out_fdput; + + ret = rw_verify_area(READ, real.file, ppos, len); + if (unlikely(ret < 0)) + goto out_fdput; + + old_cred = ovl_override_creds(file_inode(in)->i_sb); + ret = real.file->f_op->splice_read(real.file, ppos, pipe, len, flags); + + revert_creds(old_cred); + ovl_file_accessed(in); +out_fdput: + 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 +726,7 @@ 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,