* [PATCH v16 03/13] overlayfs: Implement splice-read [not found] <20230308143754.1976726-1-dhowells@redhat.com> @ 2023-03-08 14:37 ` David Howells 2023-03-08 15:33 ` Miklos Szeredi 2023-03-08 14:37 ` [PATCH v16 04/13] coda: " David Howells 1 sibling, 1 reply; 7+ messages in thread From: David Howells @ 2023-03-08 14:37 UTC (permalink / raw) 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, linux-block, linux-kernel, linux-mm, Christoph Hellwig, John Hubbard, Miklos Szeredi, linux-unionfs 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 #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, ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v16 03/13] overlayfs: Implement splice-read 2023-03-08 14:37 ` [PATCH v16 03/13] overlayfs: Implement splice-read David Howells @ 2023-03-08 15:33 ` Miklos Szeredi 2023-03-08 15:54 ` David Howells 0 siblings, 1 reply; 7+ messages in thread From: Miklos Szeredi @ 2023-03-08 15:33 UTC (permalink / raw) To: David Howells Cc: Jens Axboe, Al Viro, Christoph Hellwig, Matthew Wilcox, Jan Kara, Jeff Layton, David Hildenbrand, Jason Gunthorpe, Logan Gunthorpe, Hillf Danton, Linus Torvalds, linux-fsdevel, linux-block, linux-kernel, linux-mm, Christoph Hellwig, John Hubbard, linux-unionfs On Wed, 8 Mar 2023 at 15:38, David Howells <dhowells@redhat.com> wrote: > > 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 #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); I don't think you replied to my suggestion of using a helper here. E.g. it could be as simple as exporting do_splice_to(), or renaming it to vfs_splice_read() to be more readable. It would remove the boilerplate and be more robust if any changes are done to the splice reading code. Thanks, Miklos ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v16 03/13] overlayfs: Implement splice-read 2023-03-08 15:33 ` Miklos Szeredi @ 2023-03-08 15:54 ` David Howells 2023-03-08 15:56 ` Christoph Hellwig 0 siblings, 1 reply; 7+ messages in thread From: David Howells @ 2023-03-08 15:54 UTC (permalink / raw) To: Miklos Szeredi Cc: dhowells, Jens Axboe, Al Viro, Christoph Hellwig, Matthew Wilcox, Jan Kara, Jeff Layton, David Hildenbrand, Jason Gunthorpe, Logan Gunthorpe, Hillf Danton, Linus Torvalds, linux-fsdevel, linux-block, linux-kernel, linux-mm, Christoph Hellwig, John Hubbard, linux-unionfs Miklos Szeredi <miklos@szeredi.hu> wrote: > > + 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); > > I don't think you replied to my suggestion of using a helper here. > E.g. it could be as simple as exporting do_splice_to(), or renaming it > to vfs_splice_read() to be more readable. It would remove the > boilerplate and be more robust if any changes are done to the splice > reading code. Using do_splice_to() as a helper is probably a good idea, though both Willy and Christoph seem to dislike it. The pipe occupancy check has already been done, so I'm not sure if it should be repeated - though it probably wouldn't hurt. David ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v16 03/13] overlayfs: Implement splice-read 2023-03-08 15:54 ` David Howells @ 2023-03-08 15:56 ` Christoph Hellwig 2023-03-08 16:04 ` David Howells 0 siblings, 1 reply; 7+ messages in thread From: Christoph Hellwig @ 2023-03-08 15:56 UTC (permalink / raw) To: David Howells Cc: Miklos Szeredi, Jens Axboe, Al Viro, Christoph Hellwig, Matthew Wilcox, Jan Kara, Jeff Layton, David Hildenbrand, Jason Gunthorpe, Logan Gunthorpe, Hillf Danton, Linus Torvalds, linux-fsdevel, linux-block, linux-kernel, linux-mm, Christoph Hellwig, John Hubbard, linux-unionfs On Wed, Mar 08, 2023 at 03:54:36PM +0000, David Howells wrote: > Using do_splice_to() as a helper is probably a good idea, though both Willy > and Christoph seem to dislike it. That's not true. What I'm fundamentlly against is pointless wrappers like the call_* that add no value. do_splice_to adds useful checks, so if properly named and documented, I'm absolutely in favour. ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v16 03/13] overlayfs: Implement splice-read 2023-03-08 15:56 ` Christoph Hellwig @ 2023-03-08 16:04 ` David Howells 2023-03-09 9:29 ` Christoph Hellwig 0 siblings, 1 reply; 7+ messages in thread From: David Howells @ 2023-03-08 16:04 UTC (permalink / raw) To: Christoph Hellwig Cc: dhowells, Miklos Szeredi, Jens Axboe, Al Viro, Christoph Hellwig, Matthew Wilcox, Jan Kara, Jeff Layton, David Hildenbrand, Jason Gunthorpe, Logan Gunthorpe, Hillf Danton, Linus Torvalds, linux-fsdevel, linux-block, linux-kernel, linux-mm, John Hubbard, linux-unionfs Christoph Hellwig <hch@lst.de> wrote: > On Wed, Mar 08, 2023 at 03:54:36PM +0000, David Howells wrote: > > Using do_splice_to() as a helper is probably a good idea, though both Willy > > and Christoph seem to dislike it. > > That's not true. What I'm fundamentlly against is pointless wrappers > like the call_* that add no value. do_splice_to adds useful checks, > so if properly named and documented, I'm absolutely in favour. Fair enough. Rename to vfs_splice_read() okay with you? David ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v16 03/13] overlayfs: Implement splice-read 2023-03-08 16:04 ` David Howells @ 2023-03-09 9:29 ` Christoph Hellwig 0 siblings, 0 replies; 7+ messages in thread From: Christoph Hellwig @ 2023-03-09 9:29 UTC (permalink / raw) To: David Howells Cc: Christoph Hellwig, Miklos Szeredi, Jens Axboe, Al Viro, Christoph Hellwig, Matthew Wilcox, Jan Kara, Jeff Layton, David Hildenbrand, Jason Gunthorpe, Logan Gunthorpe, Hillf Danton, Linus Torvalds, linux-fsdevel, linux-block, linux-kernel, linux-mm, John Hubbard, linux-unionfs On Wed, Mar 08, 2023 at 04:04:39PM +0000, David Howells wrote: > Christoph Hellwig <hch@lst.de> wrote: > > > On Wed, Mar 08, 2023 at 03:54:36PM +0000, David Howells wrote: > > > Using do_splice_to() as a helper is probably a good idea, though both Willy > > > and Christoph seem to dislike it. > > > > That's not true. What I'm fundamentlly against is pointless wrappers > > like the call_* that add no value. do_splice_to adds useful checks, > > so if properly named and documented, I'm absolutely in favour. > > Fair enough. Rename to vfs_splice_read() okay with you? Yes. ^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v16 04/13] coda: Implement splice-read [not found] <20230308143754.1976726-1-dhowells@redhat.com> 2023-03-08 14:37 ` [PATCH v16 03/13] overlayfs: Implement splice-read David Howells @ 2023-03-08 14:37 ` David Howells 1 sibling, 0 replies; 7+ messages in thread From: David Howells @ 2023-03-08 14:37 UTC (permalink / raw) 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, linux-block, linux-kernel, linux-mm, Jan Harkes, Christoph Hellwig, John Hubbard, coda, codalist, linux-unionfs Implement splice-read for coda 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> Acked-by: Jan Harkes <jaharkes@cs.cmu.edu> 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: coda@cs.cmu.edu cc: codalist@coda.cs.cmu.edu cc: linux-unionfs@vger.kernel.org cc: linux-block@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- fs/coda/file.c | 36 +++++++++++++++++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-) diff --git a/fs/coda/file.c b/fs/coda/file.c index 3f3c81e6b1ab..33cd7880d30e 100644 --- a/fs/coda/file.c +++ b/fs/coda/file.c @@ -23,6 +23,7 @@ #include <linux/slab.h> #include <linux/uaccess.h> #include <linux/uio.h> +#include <linux/splice.h> #include <linux/coda.h> #include "coda_psdev.h" @@ -94,6 +95,39 @@ coda_file_write_iter(struct kiocb *iocb, struct iov_iter *to) return ret; } +static ssize_t +coda_file_splice_read(struct file *coda_file, loff_t *ppos, + struct pipe_inode_info *pipe, + size_t len, unsigned int flags) +{ + struct inode *coda_inode = file_inode(coda_file); + struct coda_file_info *cfi = coda_ftoc(coda_file); + struct file *in = cfi->cfi_container; + loff_t ki_pos = *ppos; + ssize_t ret; + + if (!in->f_op->splice_read) + return -EINVAL; + + ret = rw_verify_area(READ, in, ppos, len); + if (unlikely(ret < 0)) + return ret; + + ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode), + &cfi->cfi_access_intent, + len, ki_pos, CODA_ACCESS_TYPE_READ); + if (ret) + goto finish_read; + + ret = in->f_op->splice_read(in, ppos, pipe, len, flags); + +finish_read: + venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode), + &cfi->cfi_access_intent, + len, ki_pos, CODA_ACCESS_TYPE_READ_FINISH); + return ret; +} + static void coda_vm_open(struct vm_area_struct *vma) { @@ -302,5 +336,5 @@ const struct file_operations coda_file_operations = { .open = coda_open, .release = coda_release, .fsync = coda_fsync, - .splice_read = generic_file_splice_read, + .splice_read = coda_file_splice_read, }; ^ permalink raw reply related [flat|nested] 7+ messages in thread
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2023-03-08 14:37 ` [PATCH v16 03/13] overlayfs: Implement splice-read David Howells
2023-03-08 15:33 ` Miklos Szeredi
2023-03-08 15:54 ` David Howells
2023-03-08 15:56 ` Christoph Hellwig
2023-03-08 16:04 ` David Howells
2023-03-09 9:29 ` Christoph Hellwig
2023-03-08 14:37 ` [PATCH v16 04/13] coda: " David Howells
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