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zonefs: Always invalidate last cached page on append write 

commit c1976bd8f2 upstream.

When a direct append write is executed, the append offset may correspond
to the last page of a sequential file inode which might have been cached
already by buffered reads, page faults with mmap-read or non-direct
readahead. To ensure that the on-disk and cached data is consistant for
such last cached page, make sure to always invalidate it in
zonefs_file_dio_append(). If the invalidation fails, return -EBUSY to
userspace to differentiate from IO errors.

This invalidation will always be a no-op when the FS block size (device
zone write granularity) is equal to the page size (e.g. 4K).

Reported-by: Hans Holmberg <Hans.Holmberg@wdc.com>
Fixes: 02ef12a663 ("zonefs: use REQ_OP_ZONE_APPEND for sync DIO")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Hans Holmberg <hans.holmberg@wdc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Damien Le Moal 2023-03-29 13:16:01 +09:00 committed by Greg Kroah-Hartman
parent 2cd9d33169
commit 5cefd8fea6
1 changed files with 14 additions and 0 deletions
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14
fs/zonefs/file.c
View File

@ -382,6 +382,7 @@ static ssize_t zonefs_file_dio_append(struct kiocb *iocb, struct iov_iter *from)
struct zonefs_zone *z = zonefs_inode_zone(inode);
struct block_device *bdev = inode->i_sb->s_bdev;
unsigned int max = bdev_max_zone_append_sectors(bdev);
pgoff_t start, end;
struct bio *bio;
ssize_t size;
int nr_pages;
@ -390,6 +391,19 @@ static ssize_t zonefs_file_dio_append(struct kiocb *iocb, struct iov_iter *from)
max = ALIGN_DOWN(max << SECTOR_SHIFT, inode->i_sb->s_blocksize);
iov_iter_truncate(from, max);
/*
* If the inode block size (zone write granularity) is smaller than the
* page size, we may be appending data belonging to the last page of the
* inode straddling inode->i_size, with that page already cached due to
* a buffered read or readahead. So make sure to invalidate that page.
* This will always be a no-op for the case where the block size is
* equal to the page size.
*/
start = iocb->ki_pos >> PAGE_SHIFT;
end = (iocb->ki_pos + iov_iter_count(from) - 1) >> PAGE_SHIFT;
if (invalidate_inode_pages2_range(inode->i_mapping, start, end))
return -EBUSY;
nr_pages = iov_iter_npages(from, BIO_MAX_VECS);
if (!nr_pages)
return 0;