From: Andreas Gruenbacher <agruenba@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>
Cc: kvm-ppc@vger.kernel.org, Paul Mackerras <paulus@ozlabs.org>,
cluster-devel@redhat.com, Jan Kara <jack@suse.cz>,
Andreas Gruenbacher <agruenba@redhat.com>,
linux-kernel@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org,
ocfs2-devel@oss.oracle.com
Subject: [Ocfs2-devel] [PATCH v8 13/17] iomap: Support partial direct I/O on user copy failures
Date: Tue, 19 Oct 2021 15:42:00 +0200 [thread overview]
Message-ID: <20211019134204.3382645-14-agruenba@redhat.com> (raw)
In-Reply-To: <20211019134204.3382645-1-agruenba@redhat.com>
In iomap_dio_rw, when iomap_apply returns an -EFAULT error and the
IOMAP_DIO_PARTIAL flag is set, complete the request synchronously and
return a partial result. This allows the caller to deal with the page
fault and retry the remainder of the request.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---
fs/iomap/direct-io.c | 6 ++++++
include/linux/iomap.h | 7 +++++++
2 files changed, 13 insertions(+)
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index a2a368e824c0..a434fb7887b2 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -581,6 +581,12 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
if (iov_iter_rw(iter) == READ && iomi.pos >= dio->i_size)
iov_iter_revert(iter, iomi.pos - dio->i_size);
+ if (ret == -EFAULT && dio->size && (dio_flags & IOMAP_DIO_PARTIAL)) {
+ if (!(iocb->ki_flags & IOCB_NOWAIT))
+ wait_for_completion = true;
+ ret = 0;
+ }
+
/* magic error code to fall back to buffered I/O */
if (ret == -ENOTBLK) {
wait_for_completion = true;
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 24f8489583ca..2a213b0d1e1f 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -330,6 +330,13 @@ struct iomap_dio_ops {
*/
#define IOMAP_DIO_OVERWRITE_ONLY (1 << 1)
+/*
+ * When a page fault occurs, return a partial synchronous result and allow
+ * the caller to retry the rest of the operation after dealing with the page
+ * fault.
+ */
+#define IOMAP_DIO_PARTIAL (1 << 2)
+
ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
unsigned int dio_flags);
--
2.26.3
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next prev parent reply other threads:[~2021-10-19 13:44 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-19 13:41 [Ocfs2-devel] [PATCH v8 00/17] gfs2: Fix mmap + page fault deadlocks Andreas Gruenbacher
2021-10-19 13:41 ` [Ocfs2-devel] [PATCH v8 01/17] iov_iter: Fix iov_iter_get_pages{, _alloc} page fault return value Andreas Gruenbacher
2021-10-19 13:41 ` [Ocfs2-devel] [PATCH v8 02/17] powerpc/kvm: Fix kvm_use_magic_page Andreas Gruenbacher
2021-10-19 13:41 ` [Ocfs2-devel] [PATCH v8 03/17] gup: Turn fault_in_pages_{readable, writeable} into fault_in_{readable, writeable} Andreas Gruenbacher
2021-10-19 13:41 ` [Ocfs2-devel] [PATCH v8 04/17] iov_iter: Turn iov_iter_fault_in_readable into fault_in_iov_iter_readable Andreas Gruenbacher
2021-10-19 13:41 ` [Ocfs2-devel] [PATCH v8 05/17] iov_iter: Introduce fault_in_iov_iter_writeable Andreas Gruenbacher
2021-10-20 16:25 ` Catalin Marinas
2021-10-19 13:41 ` [Ocfs2-devel] [PATCH v8 06/17] gfs2: Add wrapper for iomap_file_buffered_write Andreas Gruenbacher
2021-10-19 13:41 ` [Ocfs2-devel] [PATCH v8 07/17] gfs2: Clean up function may_grant Andreas Gruenbacher
2021-10-19 13:41 ` [Ocfs2-devel] [PATCH v8 08/17] gfs2: Introduce flag for glock holder auto-demotion Andreas Gruenbacher
2021-10-19 13:41 ` [Ocfs2-devel] [PATCH v8 09/17] gfs2: Move the inode glock locking to gfs2_file_buffered_write Andreas Gruenbacher
2021-10-19 13:41 ` [Ocfs2-devel] [PATCH v8 10/17] gfs2: Eliminate ip->i_gh Andreas Gruenbacher
2021-10-19 13:41 ` [Ocfs2-devel] [PATCH v8 11/17] gfs2: Fix mmap + page fault deadlocks for buffered I/O Andreas Gruenbacher
2021-10-19 13:41 ` [Ocfs2-devel] [PATCH v8 12/17] iomap: Fix iomap_dio_rw return value for user copies Andreas Gruenbacher
2021-10-19 13:42 ` Andreas Gruenbacher [this message]
2021-10-19 13:42 ` [Ocfs2-devel] [PATCH v8 14/17] iomap: Add done_before argument to iomap_dio_rw Andreas Gruenbacher
2021-10-19 15:51 ` Darrick J. Wong
2021-10-19 19:30 ` Andreas Gruenbacher
2021-10-20 1:57 ` Darrick J. Wong
2021-10-19 13:42 ` [Ocfs2-devel] [PATCH v8 15/17] gup: Introduce FOLL_NOFAULT flag to disable page faults Andreas Gruenbacher
2021-10-19 13:42 ` [Ocfs2-devel] [PATCH v8 16/17] iov_iter: Introduce nofault " Andreas Gruenbacher
2021-10-19 13:42 ` [Ocfs2-devel] [PATCH v8 17/17] gfs2: Fix mmap + page fault deadlocks for direct I/O Andreas Gruenbacher
2021-10-19 15:40 ` [Ocfs2-devel] [PATCH v8 00/17] gfs2: Fix mmap + page fault deadlocks Linus Torvalds
2021-10-19 16:00 ` Bob Peterson
2021-10-20 16:36 ` Catalin Marinas
2021-10-20 20:11 ` Linus Torvalds
2021-10-20 22:44 ` Catalin Marinas
2021-10-21 6:19 ` Linus Torvalds
2021-10-22 18:06 ` Catalin Marinas
2021-10-22 19:22 ` Linus Torvalds
2021-10-25 19:00 ` Andreas Gruenbacher
2021-10-26 18:24 ` Catalin Marinas
2021-10-26 18:50 ` Linus Torvalds
2021-10-26 19:18 ` Linus Torvalds
2021-10-27 19:13 ` Catalin Marinas
2021-10-27 21:14 ` Linus Torvalds
2021-10-28 21:20 ` Catalin Marinas
2021-10-28 21:40 ` Catalin Marinas
2021-10-28 22:15 ` Andreas Grünbacher
2021-10-29 12:50 ` Catalin Marinas
2021-10-28 22:32 ` Linus Torvalds
2021-10-29 17:50 ` Catalin Marinas
2021-10-29 18:47 ` Linus Torvalds
2021-10-25 18:24 ` Andreas Gruenbacher
2021-10-26 5:12 ` Theodore Ts'o
2021-10-26 9:44 ` Andreas Gruenbacher
2021-10-27 21:21 ` Andreas Gruenbacher
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