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btrfs: Switch btrfs_trim_free_extents to find_first_clear_extent_bit

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Instead of always calling the allocator to search for a free extent,
that satisfies the input criteria, switch btrfs_trim_free_extents to
using find_first_clear_extent_bit. With this change it's no longer
necessary to read the device tree in order to figure out holes in
the devices.

Now the code always searches in-memory data structure to figure out the
space range which contains the requested which should result in speed
improvements.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Nikolay Borisov 2019-03-27 14:24:18 +02:00 committed by David Sterba
parent 45bfcfc168
commit 929be17a9b
1 changed files with 28 additions and 63 deletions
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77
fs/btrfs/extent-tree.c
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@ -11249,54 +11249,6 @@ int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
return unpin_extent_range(fs_info, start, end, false);
}
static bool should_skip_trim(struct btrfs_device *device, u64 *start, u64 *len)
{
u64 trimmed_start = 0, trimmed_end = 0;
u64 end = *start + *len - 1;
if (!find_first_extent_bit(&device->alloc_state, *start, &trimmed_start,
&trimmed_end, CHUNK_TRIMMED, NULL)) {
u64 trimmed_len = trimmed_end - trimmed_start + 1;
if (*start < trimmed_start) {
if (in_range(end, trimmed_start, trimmed_len) ||
end > trimmed_end) {
/*
* start|------|end
* ts|--|trimmed_len
* OR
* start|-----|end
* ts|-----|trimmed_len
*/
*len = trimmed_start - *start;
return false;
} else if (end < trimmed_start) {
/*
* start|------|end
* ts|--|trimmed_len
*/
return false;
}
} else if (in_range(*start, trimmed_start, trimmed_len)) {
if (in_range(end, trimmed_start, trimmed_len)) {
/*
* start|------|end
* ts|----------|trimmed_len
*/
return true;
} else {
/*
* start|-----------|end
* ts|----------|trimmed_len
*/
*start = trimmed_end + 1;
*len = end - *start + 1;
return false;
}
}
}
return false;
}
/*
* It used to be that old block groups would be left around forever.
* Iterating over them would be enough to trim unused space. Since we
@ -11320,9 +11272,10 @@ static bool should_skip_trim(struct btrfs_device *device, u64 *start, u64 *len)
static int btrfs_trim_free_extents(struct btrfs_device *device,
struct fstrim_range *range, u64 *trimmed)
{
u64 start = range->start, len = 0;
u64 start, len = 0, end = 0;
int ret;
start = max_t(u64, range->start, SZ_1M);
*trimmed = 0;
/* Discard not supported = nothing to do. */
@ -11347,34 +11300,46 @@ static int btrfs_trim_free_extents(struct btrfs_device *device,
if (ret)
break;
ret = find_free_dev_extent_start(device, range->minlen, start,
&start, &len);
find_first_clear_extent_bit(&device->alloc_state, start,
&start, &end,
CHUNK_TRIMMED | CHUNK_ALLOCATED);
/*
* If find_first_clear_extent_bit find a range that spans the
* end of the device it will set end to -1, in this case it's up
* to the caller to trim the value to the size of the device.
*/
end = min(end, device->total_bytes - 1);
len = end - start + 1;
if (ret) {
/* We didn't find any extents */
if (!len) {
mutex_unlock(&fs_info->chunk_mutex);
if (ret == -ENOSPC)
ret = 0;
break;
}
/* Keep going until we satisfy minlen or reach end of space */
if (len < range->minlen) {
mutex_unlock(&fs_info->chunk_mutex);
start += len;
continue;
}
/* If we are out of the passed range break */
if (start > range->start + range->len - 1) {
mutex_unlock(&fs_info->chunk_mutex);
ret = 0;
break;
}
start = max(range->start, start);
len = min(range->len, len);
if (!should_skip_trim(device, &start, &len)) {
ret = btrfs_issue_discard(device->bdev, start, len,
&bytes);
if (!ret)
set_extent_bits(&device->alloc_state, start,
start + bytes - 1,
CHUNK_TRIMMED);
}
mutex_unlock(&fs_info->chunk_mutex);
if (ret)