From: Goldwyn Rodrigues <rgoldwyn@suse.de>
To: linux-fsdevel@vger.kernel.org
Cc: jack@suse.com, hch@infradead.org, linux-block@vger.kernel.org,
linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-xfs@vger.kernel.org, axboe@kernel.dk,
linux-api@vger.kernel.org, adam.manzanares@wdc.com,
viro@zeniv.linux.org.uk, Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: [PATCH 04/10] fs: Introduce RWF_NOWAIT
Date: Wed, 24 May 2017 11:41:44 -0500 [thread overview]
Message-ID: <20170524164150.9492-5-rgoldwyn@suse.de> (raw)
In-Reply-To: <20170524164150.9492-1-rgoldwyn@suse.de>
From: Goldwyn Rodrigues <rgoldwyn@suse.com>
RWF_NOWAIT informs kernel to bail out if an AIO request will block
for reasons such as file allocations, or a writeback triggered,
or would block while allocating requests while performing
direct I/O.
RWF_NOWAIT is translated to IOCB_NOWAIT for iocb->ki_flags.
The check for -EOPNOTSUPP is placed in generic_file_write_iter(). This
is called by most filesystems, either through fsops.write_iter() or through
the function defined by write_iter(). If not, we perform the check defined
by .write_iter() which is called for direct IO specifically.
Filesystems xfs, btrfs and ext4 would be supported in the following patches.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/9p/vfs_file.c | 3 +++
fs/aio.c | 13 +++++++++++++
fs/ceph/file.c | 3 +++
fs/cifs/file.c | 3 +++
fs/fuse/file.c | 3 +++
fs/nfs/direct.c | 3 +++
fs/ocfs2/file.c | 3 +++
include/linux/fs.h | 5 ++++-
include/uapi/linux/fs.h | 1 +
mm/filemap.c | 3 +++
10 files changed, 39 insertions(+), 1 deletion(-)
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 3de3b4a89d89..403681db7723 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -411,6 +411,9 @@ v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
loff_t origin;
int err = 0;
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ return -EOPNOTSUPP;
+
retval = generic_write_checks(iocb, from);
if (retval <= 0)
return retval;
diff --git a/fs/aio.c b/fs/aio.c
index 020fa0045e3c..9616dc733103 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1592,6 +1592,19 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
goto out_put_req;
}
+ if (req->common.ki_flags & IOCB_NOWAIT) {
+ if (!(req->common.ki_flags & IOCB_DIRECT)) {
+ ret = -EOPNOTSUPP;
+ goto out_put_req;
+ }
+
+ if ((iocb->aio_lio_opcode != IOCB_CMD_PWRITE) &&
+ (iocb->aio_lio_opcode != IOCB_CMD_PWRITEV)) {
+ ret = -EINVAL;
+ goto out_put_req;
+ }
+ }
+
ret = put_user(KIOCB_KEY, &user_iocb->aio_key);
if (unlikely(ret)) {
pr_debug("EFAULT: aio_key\n");
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 3fdde0b283c9..a53fd2675b1b 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1300,6 +1300,9 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
int err, want, got;
loff_t pos;
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ return -EOPNOTSUPP;
+
if (ceph_snap(inode) != CEPH_NOSNAP)
return -EROFS;
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 0fd081bd2a2f..ff84fa9ddb6c 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2725,6 +2725,9 @@ ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
* write request.
*/
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ return -EOPNOTSUPP;
+
rc = generic_write_checks(iocb, from);
if (rc <= 0)
return rc;
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 3ee4fdc3da9e..812c7bd0c290 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1425,6 +1425,9 @@ static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(file);
ssize_t res;
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ return -EOPNOTSUPP;
+
if (is_bad_inode(inode))
return -EIO;
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 6fb9fad2d1e6..c8e7dd76126c 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -979,6 +979,9 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter)
dfprintk(FILE, "NFS: direct write(%pD2, %zd@%Ld)\n",
file, iov_iter_count(iter), (long long) iocb->ki_pos);
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ return -EOPNOTSUPP;
+
result = generic_write_checks(iocb, iter);
if (result <= 0)
return result;
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index bfeb647459d9..e7f8ba890305 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -2235,6 +2235,9 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
if (count == 0)
return 0;
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ return -EOPNOTSUPP;
+
direct_io = iocb->ki_flags & IOCB_DIRECT ? 1 : 0;
inode_lock(inode);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index dc0ab585cd56..2a7d14af6d12 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -268,6 +268,7 @@ struct writeback_control;
#define IOCB_DSYNC (1 << 4)
#define IOCB_SYNC (1 << 5)
#define IOCB_WRITE (1 << 6)
+#define IOCB_NOWAIT (1 << 7)
struct kiocb {
struct file *ki_filp;
@@ -3060,7 +3061,7 @@ static inline int iocb_flags(struct file *file)
static inline int kiocb_set_rw_flags(struct kiocb *ki, int flags)
{
- if (unlikely(flags & ~(RWF_HIPRI | RWF_DSYNC | RWF_SYNC)))
+ if (unlikely(flags & ~(RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT)))
return -EOPNOTSUPP;
if (flags & RWF_HIPRI)
@@ -3069,6 +3070,8 @@ static inline int kiocb_set_rw_flags(struct kiocb *ki, int flags)
ki->ki_flags |= IOCB_DSYNC;
if (flags & RWF_SYNC)
ki->ki_flags |= (IOCB_DSYNC | IOCB_SYNC);
+ if (flags & RWF_NOWAIT)
+ ki->ki_flags |= IOCB_NOWAIT;
return 0;
}
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 24e61a54feaa..29969fb7f9a7 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -360,5 +360,6 @@ struct fscrypt_key {
#define RWF_HIPRI 0x00000001 /* high priority request, poll if possible */
#define RWF_DSYNC 0x00000002 /* per-IO O_DSYNC */
#define RWF_SYNC 0x00000004 /* per-IO O_SYNC */
+#define RWF_NOWAIT 0x00000008 /* per-IO, return -EAGAIN if operation would block */
#endif /* _UAPI_LINUX_FS_H */
diff --git a/mm/filemap.c b/mm/filemap.c
index 87aba7698584..097213275461 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3006,6 +3006,9 @@ ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
struct inode *inode = file->f_mapping->host;
ssize_t ret;
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ return -EOPNOTSUPP;
+
inode_lock(inode);
ret = generic_write_checks(iocb, from);
if (ret > 0)
--
2.12.0
next prev parent reply other threads:[~2017-05-24 16:41 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-24 16:41 [PATCH 0/10 v9] No wait AIO Goldwyn Rodrigues
2017-05-24 16:41 ` [PATCH 01/10] fs: Separate out kiocb flags setup based on RWF_* flags Goldwyn Rodrigues
2017-05-25 8:16 ` Jan Kara
2017-05-24 16:41 ` [PATCH 02/10] fs: Introduce filemap_range_has_page() Goldwyn Rodrigues
2017-05-25 8:25 ` Jan Kara
[not found] ` <20170524164150.9492-1-rgoldwyn-l3A5Bk7waGM@public.gmane.org>
2017-05-24 16:41 ` [PATCH 03/10] fs: Use RWF_* flags for AIO operations Goldwyn Rodrigues
2017-05-25 8:27 ` Jan Kara
2017-05-24 16:41 ` [PATCH 05/10] fs: return if direct write will trigger writeback Goldwyn Rodrigues
2017-05-25 8:32 ` Jan Kara
2017-05-28 9:27 ` [PATCH 0/10 v9] No wait AIO Christoph Hellwig
2017-05-29 2:38 ` Goldwyn Rodrigues
2017-05-29 8:32 ` Christoph Hellwig
2017-05-24 16:41 ` Goldwyn Rodrigues [this message]
2017-05-25 8:30 ` [PATCH 04/10] fs: Introduce RWF_NOWAIT Jan Kara
2017-05-24 16:41 ` [PATCH 06/10] fs: Introduce IOMAP_NOWAIT Goldwyn Rodrigues
2017-05-25 8:33 ` Jan Kara
2017-05-24 16:41 ` [PATCH 07/10] fs: return on congested block device Goldwyn Rodrigues
2017-05-24 16:41 ` [PATCH 08/10] ext4: nowait aio support Goldwyn Rodrigues
2017-05-24 16:41 ` [PATCH 09/10] xfs: " Goldwyn Rodrigues
2017-05-24 16:49 ` Darrick J. Wong
[not found] ` <20170524164150.9492-10-rgoldwyn-l3A5Bk7waGM@public.gmane.org>
2017-05-28 9:31 ` Christoph Hellwig
2017-05-29 2:38 ` Goldwyn Rodrigues
2017-05-29 8:21 ` Jan Kara
2017-05-29 8:33 ` Christoph Hellwig
[not found] ` <20170529083338.GC1899-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2017-05-30 16:13 ` Goldwyn Rodrigues
2017-05-31 8:51 ` Jan Kara
2017-05-24 16:41 ` [PATCH 10/10] btrfs: " Goldwyn Rodrigues
-- strict thread matches above, loose matches on Subject: below --
2017-06-06 11:19 [PATCH 0/10 v11] No wait AIO Goldwyn Rodrigues
2017-06-06 11:19 ` [PATCH 04/10] fs: Introduce RWF_NOWAIT Goldwyn Rodrigues
[not found] ` <20170606111939.27272-5-rgoldwyn-l3A5Bk7waGM@public.gmane.org>
2017-06-10 5:27 ` Al Viro
2017-06-05 5:35 [PATCH 0/10 v10] No wait AIO Goldwyn Rodrigues
2017-06-05 5:35 ` [PATCH 04/10] fs: Introduce RWF_NOWAIT Goldwyn Rodrigues
2017-05-11 19:17 [PATCH 0/10 v8] No wait AIO Goldwyn Rodrigues
2017-05-11 19:17 ` [PATCH 04/10] fs: Introduce RWF_NOWAIT Goldwyn Rodrigues
[not found] ` <20170511191710.31959-5-rgoldwyn-l3A5Bk7waGM@public.gmane.org>
2017-05-15 9:47 ` Jan Kara
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