kernel.git/fs/netfs/io.c, branch linux-6.10.y

netfs, cifs: Fix handling of short DIO read

2024-09-12T09:12:55Z

[ Upstream commit 1da29f2c39b67b846b74205c81bf0ccd96d34727 ] Short DIO reads, particularly in relation to cifs, are not being handled correctly by cifs and netfslib. This can be tested by doing a DIO read of a file where the size of read is larger than the size of the file. When it crosses the EOF, it gets a short read and this gets retried, and in the case of cifs, the retry read fails, with the failure being translated to ENODATA. Fix this by the following means: (1) Add a flag, NETFS_SREQ_HIT_EOF, for the filesystem to set when it detects that the read did hit the EOF. (2) Make the netfslib read assessment stop processing subrequests when it encounters one with that flag set. (3) Return rreq->transferred, the accumulated contiguous amount read to that point, to userspace for a DIO read. (4) Make cifs set the flag and clear the error if the read RPC returned ENODATA. (5) Make cifs set the flag and clear the error if a short read occurred without error and the read-to file position is now at the remote inode size. Fixes: 69c3c023af25 ("cifs: Implement netfslib hooks") Signed-off-by: David Howells cc: Steve French cc: Paulo Alcantara cc: Jeff Layton cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Steve French Signed-off-by: Sasha Levin

cifs: Fix lack of credit renegotiation on read retry

2024-09-12T09:12:55Z

[ Upstream commit 6a5dcd487791e0c2d86622064602a5c7459941ed ] When netfslib asks cifs to issue a read operation, it prefaces this with a call to ->clamp_length() which cifs uses to negotiate credits, providing receive capacity on the server; however, in the event that a read op needs reissuing, netfslib doesn't call ->clamp_length() again as that could shorten the subrequest, leaving a gap. This causes the retried read to be done with zero credits which causes the server to reject it with STATUS_INVALID_PARAMETER. This is a problem for a DIO read that is requested that would go over the EOF. The short read will be retried, causing EINVAL to be returned to the user when it fails. Fix this by making cifs_req_issue_read() negotiate new credits if retrying (NETFS_SREQ_RETRYING now gets set in the read side as well as the write side in this instance). This isn't sufficient, however: the new credits might not be sufficient to complete the remainder of the read, so also add an additional field, rreq->actual_len, that holds the actual size of the op we want to perform without having to alter subreq->len. We then rely on repeated short reads being retried until we finish the read or reach the end of file and make a zero-length read. Also fix a couple of places where the subrequest start and length need to be altered by the amount so far transferred when being used. Fixes: 69c3c023af25 ("cifs: Implement netfslib hooks") Signed-off-by: David Howells cc: Steve French cc: Paulo Alcantara cc: Jeff Layton cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Steve French Signed-off-by: Sasha Levin

netfs: Fix missing iterator reset on retry of short read

2024-09-04T11:30:05Z

[ Upstream commit 950b03d0f664a54389a555d79215348ed413161f ] Fix netfs_rreq_perform_resubmissions() to reset before retrying a short read, otherwise the wrong part of the output buffer will be used. Fixes: 92b6cc5d1e7c ("netfs: Add iov_iters to (sub)requests to describe various buffers") Signed-off-by: David Howells Link: https://lore.kernel.org/r/20240823200819.532106-6-dhowells@redhat.com cc: Steve French cc: Paulo Alcantara cc: Jeff Layton cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin

netfs, ceph: Revert "netfs: Remove deprecated use of PG_private_2 as a second writeback flag"

2024-08-29T15:35:34Z

commit 8e5ced7804cb9184c4a23f8054551240562a8eda upstream. This reverts commit ae678317b95e760607c7b20b97c9cd4ca9ed6e1a. Revert the patch that removes the deprecated use of PG_private_2 in netfslib for the moment as Ceph is actually still using this to track data copied to the cache. Fixes: ae678317b95e ("netfs: Remove deprecated use of PG_private_2 as a second writeback flag") Reported-by: Max Kellermann Signed-off-by: David Howells cc: Ilya Dryomov cc: Xiubo Li cc: Jeff Layton cc: Matthew Wilcox cc: ceph-devel@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org https: //lore.kernel.org/r/3575457.1722355300@warthog.procyon.org.uk Signed-off-by: Christian Brauner Signed-off-by: Greg Kroah-Hartman

netfs: Switch debug logging to pr_debug()

2024-06-12T12:25:41Z

Instead of inventing a custom way to conditionally enable debugging, just make use of pr_debug(), which also has dynamic debugging facilities and is more likely known to someone who hunts a problem in the netfs code. Also drop the module parameter netfs_debug which didn't have any effect without further source changes. (The variable netfs_debug was only used in #ifdef blocks for cpp vars that don't exist; Note that CONFIG_NETFS_DEBUG isn't settable via kconfig, a variable with that name never existed in the mainline and is probably just taken over (and renamed) from similar custom debug logging implementations.) Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20240608151352.22860-2-ukleinek@kernel.org Signed-off-by: Christian Brauner

cifs: Cut over to using netfslib

2024-05-01T17:08:21Z

Make the cifs filesystem use netfslib to handle reading and writing on behalf of cifs. The changes include: (1) Various read_iter/write_iter type functions are turned into wrappers around netfslib API functions or are pointed directly at those functions: cifs_file_direct{,_nobrl}_ops switch to use netfs_unbuffered_read_iter and netfs_unbuffered_write_iter. Large pieces of code that will be removed are #if'd out and will be removed in subsequent patches. [?] Why does cifs mark the page dirty in the destination buffer of a DIO read? Should that happen automatically? Does netfs need to do that? Signed-off-by: David Howells cc: Steve French cc: Shyam Prasad N cc: Rohith Surabattula cc: Jeff Layton cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org

netfs: Switch to using unsigned long long rather than loff_t

2024-05-01T17:07:35Z

Switch to using unsigned long long rather than loff_t in netfslib to avoid problems with the sign flipping in the maths when we're dealing with the byte at position 0x7fffffffffffffff. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: Ilya Dryomov cc: Xiubo Li cc: netfs@lists.linux.dev cc: ceph-devel@vger.kernel.org cc: linux-fsdevel@vger.kernel.org

netfs: Use subreq_counter to allocate subreq debug_index values

2024-04-29T14:01:44Z

Use the subreq_counter in netfs_io_request to allocate subrequest debug_index values in read ops as well as write ops. Signed-off-by: David Howells cc: Jeff Layton cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org

netfs: Remove deprecated use of PG_private_2 as a second writeback flag

2024-04-29T14:01:43Z

Remove the deprecated use of PG_private_2 in netfslib. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: Matthew Wilcox (Oracle) cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org

mm: Remove the PG_fscache alias for PG_private_2

2024-04-29T14:01:42Z

Remove the PG_fscache alias for PG_private_2 and use the latter directly. Use of this flag for marking pages undergoing writing to the cache should be considered deprecated and the folios should be marked dirty instead and the write done in ->writepages(). Note that PG_private_2 itself should be considered deprecated and up for future removal by the MM folks too. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: Matthew Wilcox (Oracle) cc: Ilya Dryomov cc: Xiubo Li cc: Steve French cc: Paulo Alcantara cc: Ronnie Sahlberg cc: Shyam Prasad N cc: Tom Talpey cc: Bharath SM cc: Trond Myklebust cc: Anna Schumaker cc: netfs@lists.linux.dev cc: ceph-devel@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: linux-nfs@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org