Per Qu Wenruo in case we have a very large disk, e.g. 8TiB device, mostly empty although we will do the split according to our super block locations, the last super block ends at 256G, we can submit a huge discard for the range [256G, 8T), causing a super large delay. We now split the space left to discard based the block discard limit in preparation of introduction of cancellation signals handling. Reported-by: Qu Wenruo <wqu@xxxxxxxx> Closes: https://lore.kernel.org/lkml/2e15214b-7e95-4e64-a899-725de12c9037@xxxxxxxxx/T/#mdfef1d8b36334a15c54cd009f6aadf49e260e105 Signed-off-by: Luca Stefani <luca.stefani.ge1@xxxxxxxxx> --- fs/btrfs/extent-tree.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index feec49e6f9c8..894684f4f497 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -1239,8 +1239,9 @@ static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len, u64 *discarded_bytes) { int j, ret = 0; - u64 bytes_left, end; + u64 bytes_left, bytes_to_discard, end; u64 aligned_start = ALIGN(start, 1 << SECTOR_SHIFT); + sector_t sector, nr_sects, bio_sects; /* Adjust the range to be aligned to 512B sectors if necessary. */ if (start != aligned_start) { @@ -1300,13 +1301,23 @@ static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len, bytes_left = end - start; } - if (bytes_left) { - ret = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT, - bytes_left >> SECTOR_SHIFT, - GFP_NOFS); + while (bytes_left) { + sector = start >> SECTOR_SHIFT; + nr_sects = bytes_left >> SECTOR_SHIFT; + bio_sects = min(nr_sects, bio_discard_limit(bdev, sector)); + bytes_to_discard = bio_sects << SECTOR_SHIFT; + + ret = blkdev_issue_discard(bdev, sector, bio_sects, GFP_NOFS); + if (!ret) - *discarded_bytes += bytes_left; + *discarded_bytes += bytes_to_discard; + else if (ret != -EOPNOTSUPP) + return ret; + + start += bytes_to_discard; + bytes_left -= bytes_to_discard; } + return ret; } -- 2.46.0
