From: Damien Le Moal damien.lemoal@opensource.wdc.com
commit c1976bd8f23016d8706973908f2bb0ac0d852a8f 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: 02ef12a663c7 ("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 --- fs/zonefs/file.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
--- a/fs/zonefs/file.c +++ b/fs/zonefs/file.c @@ -382,6 +382,7 @@ static ssize_t zonefs_file_dio_append(st 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(st 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;