From: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx> Subject: block: invalidate the page cache when issuing BLKZEROOUT Patch series "fallocate for block devices", v11. This is a patchset to fix page cache coherency with BLKZEROOUT and implement fallocate for block devices. The first patch is a fix to the existing BLKZEROOUT ioctl to invalidate the page cache if the zeroing command to the underlying device succeeds. Without this patch we still have the pagecache coherence bug that's been in the kernel forever. The second patch changes the internal block device functions to reject attempts to discard or zeroout that are not aligned to the logical block size. Previously, we only checked that the start/len parameters were 512-byte aligned, which caused kernel BUG_ONs for unaligned IOs to 4k-LBA devices. The third patch creates an fallocate handler for block devices, wires up the FALLOC_FL_PUNCH_HOLE flag to zeroing-discard, and connects FALLOC_FL_ZERO_RANGE to write-same so that we can have a consistent fallocate interface between files and block devices. It also allows the combination of PUNCH_HOLE and NO_HIDE_STALE to invoke non-zeroing discard. Test cases for the new block device fallocate are now in xfstests as generic/349-351. This patch (of 3): Invalidate the page cache (as a regular O_DIRECT write would do) to avoid returning stale cache contents at a later time. Link: http://lkml.kernel.org/r/147518378313.22791.16649519283678515021.stgit@xxxxxxxxxxxxxxxx Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Reviewed-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx> Reviewed-by: Hannes Reinecke <hare@xxxxxxxx> Cc: Theodore Ts'o <tytso@xxxxxxx> Cc: Mike Snitzer <snitzer@xxxxxxxxxx> Cc: Brian Foster <bfoster@xxxxxxxxxx> Cc: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- block/ioctl.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff -puN block/ioctl.c~block-invalidate-the-page-cache-when-issuing-blkzeroout block/ioctl.c --- a/block/ioctl.c~block-invalidate-the-page-cache-when-issuing-blkzeroout +++ a/block/ioctl.c @@ -225,7 +225,8 @@ static int blk_ioctl_zeroout(struct bloc unsigned long arg) { uint64_t range[2]; - uint64_t start, len; + struct address_space *mapping; + uint64_t start, end, len; if (!(mode & FMODE_WRITE)) return -EBADF; @@ -235,18 +236,23 @@ static int blk_ioctl_zeroout(struct bloc start = range[0]; len = range[1]; + end = start + len - 1; if (start & 511) return -EINVAL; if (len & 511) return -EINVAL; - start >>= 9; - len >>= 9; - - if (start + len > (i_size_read(bdev->bd_inode) >> 9)) + if (end >= (uint64_t)i_size_read(bdev->bd_inode)) + return -EINVAL; + if (end < start) return -EINVAL; - return blkdev_issue_zeroout(bdev, start, len, GFP_KERNEL, false); + /* Invalidate the page cache, including dirty pages */ + mapping = bdev->bd_inode->i_mapping; + truncate_inode_pages_range(mapping, start, end); + + return blkdev_issue_zeroout(bdev, start >> 9, len >> 9, GFP_KERNEL, + false); } static int put_ushort(unsigned long arg, unsigned short val) _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
