iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

iomap: Add done_before argument to iomap_dio_rw

Browse Source 
Add a done_before argument to iomap_dio_rw that indicates how much of
the request has already been transferred.  When the request succeeds, we
report that done_before additional bytes were tranferred.  This is
useful for finishing a request asynchronously when part of the request
has already been completed synchronously.

We'll use that to allow iomap_dio_rw to be used with page faults
disabled: when a page fault occurs while submitting a request, we
synchronously complete the part of the request that has already been
submitted.  The caller can then take care of the page fault and call
iomap_dio_rw again for the rest of the request, passing in the number of
bytes already tranferred.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
This commit is contained in:
Andreas Gruenbacher 2021-07-24 12:26:41 +02:00
parent 97308f8b0d
commit 4fdccaa0d1
8 changed files with 32 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
fs/btrfs/file.c
View File

@ -1957,7 +1957,7 @@ relock:
}
dio = __iomap_dio_rw(iocb, from, &btrfs_dio_iomap_ops, &btrfs_dio_ops,
0);
0, 0);
btrfs_inode_unlock(inode, ilock_flags);
@ -3658,7 +3658,8 @@ static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to)
return 0;
btrfs_inode_lock(inode, BTRFS_ILOCK_SHARED);
ret = iomap_dio_rw(iocb, to, &btrfs_dio_iomap_ops, &btrfs_dio_ops, 0);
ret = iomap_dio_rw(iocb, to, &btrfs_dio_iomap_ops, &btrfs_dio_ops,
0, 0);
btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
return ret;
}

2
fs/erofs/data.c
View File

@ -287,7 +287,7 @@ static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
if (!err)
return iomap_dio_rw(iocb, to, &erofs_iomap_ops,
NULL, 0);
NULL, 0, 0);
if (err < 0)
return err;
}

5
fs/ext4/file.c
View File

@ -74,7 +74,7 @@ static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
return generic_file_read_iter(iocb, to);
}
ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, 0);
ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, 0, 0);
inode_unlock_shared(inode);
file_accessed(iocb->ki_filp);
@ -566,7 +566,8 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (ilock_shared)
iomap_ops = &ext4_iomap_overwrite_ops;
ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
(unaligned_io || extend) ? IOMAP_DIO_FORCE_WAIT : 0);
(unaligned_io || extend) ? IOMAP_DIO_FORCE_WAIT : 0,
0);
if (ret == -ENOTBLK)
ret = 0;

4
fs/gfs2/file.c
View File

@ -822,7 +822,7 @@ static ssize_t gfs2_file_direct_read(struct kiocb *iocb, struct iov_iter *to,
if (ret)
goto out_uninit;
ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL, 0);
ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL, 0, 0);
gfs2_glock_dq(gh);
out_uninit:
gfs2_holder_uninit(gh);
@ -856,7 +856,7 @@ static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from,
if (offset + len > i_size_read(&ip->i_inode))
goto out;
ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL, 0);
ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL, 0, 0);
if (ret == -ENOTBLK)
ret = 0;
out:

19
fs/iomap/direct-io.c
View File

@ -31,6 +31,7 @@ struct iomap_dio {
atomic_t ref;
unsigned flags;
int error;
size_t done_before;
bool wait_for_completion;
union {
@ -124,6 +125,9 @@ ssize_t iomap_dio_complete(struct iomap_dio *dio)
if (ret > 0 && (dio->flags & IOMAP_DIO_NEED_SYNC))
ret = generic_write_sync(iocb, ret);
if (ret > 0)
ret += dio->done_before;
kfree(dio);
return ret;
@ -450,13 +454,21 @@ static loff_t iomap_dio_iter(const struct iomap_iter *iter,
* may be pure data writes. In that case, we still need to do a full data sync
* completion.
*
* When page faults are disabled and @dio_flags includes IOMAP_DIO_PARTIAL,
* __iomap_dio_rw can return a partial result if it encounters a non-resident
* page in @iter after preparing a transfer. In that case, the non-resident
* pages can be faulted in and the request resumed with @done_before set to the
* number of bytes previously transferred. The request will then complete with
* the correct total number of bytes transferred; this is essential for
* completing partial requests asynchronously.
*
* Returns -ENOTBLK In case of a page invalidation invalidation failure for
* writes. The callers needs to fall back to buffered I/O in this case.
*/
struct iomap_dio *
__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)
unsigned int dio_flags, size_t done_before)
{
struct address_space *mapping = iocb->ki_filp->f_mapping;
struct inode *inode = file_inode(iocb->ki_filp);
@ -486,6 +498,7 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
dio->dops = dops;
dio->error = 0;
dio->flags = 0;
dio->done_before = done_before;
dio->submit.iter = iter;
dio->submit.waiter = current;
@ -652,11 +665,11 @@ EXPORT_SYMBOL_GPL(__iomap_dio_rw);
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)
unsigned int dio_flags, size_t done_before)
{
struct iomap_dio *dio;
dio = __iomap_dio_rw(iocb, iter, ops, dops, dio_flags);
dio = __iomap_dio_rw(iocb, iter, ops, dops, dio_flags, done_before);
if (IS_ERR_OR_NULL(dio))
return PTR_ERR_OR_ZERO(dio);
return iomap_dio_complete(dio);

6
fs/xfs/xfs_file.c
View File

@ -259,7 +259,7 @@ xfs_file_dio_read(
ret = xfs_ilock_iocb(iocb, XFS_IOLOCK_SHARED);
if (ret)
return ret;
ret = iomap_dio_rw(iocb, to, &xfs_read_iomap_ops, NULL, 0);
ret = iomap_dio_rw(iocb, to, &xfs_read_iomap_ops, NULL, 0, 0);
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
return ret;
@ -569,7 +569,7 @@ xfs_file_dio_write_aligned(
}
trace_xfs_file_direct_write(iocb, from);
ret = iomap_dio_rw(iocb, from, &xfs_direct_write_iomap_ops,
&xfs_dio_write_ops, 0);
&xfs_dio_write_ops, 0, 0);
out_unlock:
if (iolock)
xfs_iunlock(ip, iolock);
@ -647,7 +647,7 @@ retry_exclusive:
trace_xfs_file_direct_write(iocb, from);
ret = iomap_dio_rw(iocb, from, &xfs_direct_write_iomap_ops,
&xfs_dio_write_ops, flags);
&xfs_dio_write_ops, flags, 0);
/*
* Retry unaligned I/O with exclusive blocking semantics if the DIO

4
fs/zonefs/super.c
View File

@ -852,7 +852,7 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
ret = zonefs_file_dio_append(iocb, from);
else
ret = iomap_dio_rw(iocb, from, &zonefs_iomap_ops,
&zonefs_write_dio_ops, 0);
&zonefs_write_dio_ops, 0, 0);
if (zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
(ret > 0 || ret == -EIOCBQUEUED)) {
if (ret > 0)
@ -987,7 +987,7 @@ static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
}
file_accessed(iocb->ki_filp);
ret = iomap_dio_rw(iocb, to, &zonefs_iomap_ops,
&zonefs_read_dio_ops, 0);
&zonefs_read_dio_ops, 0, 0);
} else {
ret = generic_file_read_iter(iocb, to);
if (ret == -EIO)

4
include/linux/iomap.h
View File

@ -339,10 +339,10 @@ struct iomap_dio_ops {
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);
unsigned int dio_flags, size_t done_before);
struct iomap_dio *__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);
unsigned int dio_flags, size_t done_before);
ssize_t iomap_dio_complete(struct iomap_dio *dio);
int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);