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Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <20230214171330.2722188-1-dhowells@redhat.com> <20230214171330.2722188-6-dhowells@redhat.com> To: Miklos Szeredi Cc: dhowells@redhat.com, Jens Axboe , Al Viro , Christoph Hellwig , Matthew Wilcox , Jan Kara , Jeff Layton , David Hildenbrand , Jason Gunthorpe , Logan Gunthorpe , Hillf Danton , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Christoph Hellwig , John Hubbard , linux-unionfs@vger.kernel.org Subject: [PATCH v15 05/17] overlayfs: Implement splice-read MIME-Version: 1.0 Content-ID: <3370084.1676475658.1@warthog.procyon.org.uk> Date: Wed, 15 Feb 2023 15:40:58 +0000 Message-ID: <3370085.1676475658@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: F1F7F20026 X-Stat-Signature: sz8k9q9ow1cjrcpj89tzd5sztka1cbn8 X-HE-Tag: 1676475669-875824 X-HE-Meta: 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 h06ftxeV FgtDWz+iGs0TREGMKe1hdW0l3G5lkbjHqLlZO5GXEUXXr2ctf44RD9oCnVWHnp5BFiV5f3RsZ0A251x0zbggiTFcaC5BrNDXMsTXcBge27rVLXHVEr98iTgR0JXZXpIqE+8aYsxQG3Jnpz/fn+F4TlAarflAGsMqtspMAgvZSadsT1nF4G3ZdWl4Wq0U0gUYLWLX8aN2o17wKhlzAuOQT+Rt+rz/BfvLZISD+9Q/10RWkk3xwrHz+38103Ti542zHZ/b0hJFb1Rybk2m40+UttmNgEIS2yfiPtgYW3nAM9HdufRdmASaU3iSno74ejNORQevNdrr6xAMhC751Yf9OfaLUN8zksSrM9yuY8fIYpmNM+mRkm2i4B5YgaZDDomiDYycXLGS2lfaw8Ee8Xb0Dfb6mTs+lwlsw7tTuM8gGvQeDcdxDnsxvZeyBexn0qSuZRKKBHv6EXE4Go2E= 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: How about the attached then? David --- overlayfs: Implement splice-read 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 c9d0c362c7ef..72a545da51a2 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,