iomap: fall back to buffered writes for invalidation failures

Failing to invalid the page cache means data in incoherent, which is
a very bad state for the system.  Always fall back to buffered I/O
through the page cache if we can't invalidate mappings.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Theodore Ts'o <tytso@mit.edu> # for ext4
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com> # for gfs2
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
This commit is contained in:
Christoph Hellwig 2020-07-23 22:45:59 -07:00 committed by Darrick J. Wong
parent 80e543ae24
commit 60263d5889
6 changed files with 23 additions and 10 deletions

View File

@ -544,6 +544,8 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
iomap_ops = &ext4_iomap_overwrite_ops;
ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
is_sync_kiocb(iocb) || unaligned_io || extend);
if (ret == -ENOTBLK)
ret = 0;
if (extend)
ret = ext4_handle_inode_extension(inode, offset, ret, count);

View File

@ -814,7 +814,8 @@ static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL,
is_sync_kiocb(iocb));
if (ret == -ENOTBLK)
ret = 0;
out:
gfs2_glock_dq(&gh);
out_uninit:

View File

@ -10,6 +10,7 @@
#include <linux/backing-dev.h>
#include <linux/uio.h>
#include <linux/task_io_accounting_ops.h>
#include "trace.h"
#include "../internal.h"
@ -401,6 +402,9 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length,
* can be mapped into multiple disjoint IOs and only a subset of the IOs issued
* may be pure data writes. In that case, we still need to do a full data sync
* completion.
*
* 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.
*/
ssize_t
iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
@ -478,13 +482,15 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
if (iov_iter_rw(iter) == WRITE) {
/*
* Try to invalidate cache pages for the range we are writing.
* If this invalidation fails, tough, the write will still work,
* but racing two incompatible write paths is a pretty crazy
* thing to do, so we don't support it 100%.
* If this invalidation fails, let the caller fall back to
* buffered I/O.
*/
if (invalidate_inode_pages2_range(mapping, pos >> PAGE_SHIFT,
end >> PAGE_SHIFT))
dio_warn_stale_pagecache(iocb->ki_filp);
end >> PAGE_SHIFT)) {
trace_iomap_dio_invalidate_fail(inode, pos, count);
ret = -ENOTBLK;
goto out_free_dio;
}
if (!wait_for_completion && !inode->i_sb->s_dio_done_wq) {
ret = sb_init_dio_done_wq(inode->i_sb);

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@ -74,6 +74,7 @@ DEFINE_EVENT(iomap_range_class, name, \
DEFINE_RANGE_EVENT(iomap_writepage);
DEFINE_RANGE_EVENT(iomap_releasepage);
DEFINE_RANGE_EVENT(iomap_invalidatepage);
DEFINE_RANGE_EVENT(iomap_dio_invalidate_fail);
#define IOMAP_TYPE_STRINGS \
{ IOMAP_HOLE, "HOLE" }, \

View File

@ -553,8 +553,8 @@ out:
xfs_iunlock(ip, iolock);
/*
* No fallback to buffered IO on errors for XFS, direct IO will either
* complete fully or fail.
* No fallback to buffered IO after short writes for XFS, direct I/O
* will either complete fully or return an error.
*/
ASSERT(ret < 0 || ret == count);
return ret;

View File

@ -786,8 +786,11 @@ static ssize_t zonefs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (iocb->ki_pos >= ZONEFS_I(inode)->i_max_size)
return -EFBIG;
if (iocb->ki_flags & IOCB_DIRECT)
return zonefs_file_dio_write(iocb, from);
if (iocb->ki_flags & IOCB_DIRECT) {
ssize_t ret = zonefs_file_dio_write(iocb, from);
if (ret != -ENOTBLK)
return ret;
}
return zonefs_file_buffered_write(iocb, from);
}