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Message-ID: <20240902205828.943155-3-luca.stefani.ge1@gmail.com>
Date: Mon, 2 Sep 2024 22:56:11 +0200
From: Luca Stefani <luca.stefani.ge1@...il.com>
To:
Cc: Luca Stefani <luca.stefani.ge1@...il.com>,
Qu Wenruo <wqu@...e.com>,
Jens Axboe <axboe@...nel.dk>,
Chris Mason <clm@...com>,
Josef Bacik <josef@...icpanda.com>,
David Sterba <dsterba@...e.com>,
linux-block@...r.kernel.org,
linux-kernel@...r.kernel.org,
linux-btrfs@...r.kernel.org
Subject: [PATCH v2 2/3] btrfs: Split remaining space to discard in chunks
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@...e.com>
Closes: https://lore.kernel.org/lkml/2e15214b-7e95-4e64-a899-725de12c9037@gmail.com/T/#mdfef1d8b36334a15c54cd009f6aadf49e260e105
Signed-off-by: Luca Stefani <luca.stefani.ge1@...il.com>
---
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
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