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btrfs: add cancellation points to trim loops

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There are reports that system cannot suspend due to running trim because
the task responsible for trimming the device isn't able to finish in
time, especially since we have a free extent discarding phase, which can
trim a lot of unallocated space. There are no limits on the trim size
(unlike the block group part).

Since trime isn't a critical call it can be interrupted at any time,
in such cases we stop the trim, report the amount of discarded bytes and
return an error.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=219180
Link: https://bugzilla.suse.com/show_bug.cgi?id=1229737
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Luca Stefani <luca.stefani.ge1@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Luca Stefani 2024-09-17 22:33:05 +02:00 committed by David Sterba
parent a99fcb0158
commit 69313850dc
3 changed files with 14 additions and 3 deletions
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7
fs/btrfs/extent-tree.c
View File

@ -1316,6 +1316,11 @@ static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
start += bytes_to_discard;
bytes_left -= bytes_to_discard;
*discarded_bytes += bytes_to_discard;
if (btrfs_trim_interrupted()) {
ret = -ERESTARTSYS;
break;
}
}
return ret;
@ -6470,7 +6475,7 @@ static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed)
start += len;
*trimmed += bytes;
if (fatal_signal_pending(current)) {
if (btrfs_trim_interrupted()) {
ret = -ERESTARTSYS;
break;
}

4
fs/btrfs/free-space-cache.c
View File

@ -3809,7 +3809,7 @@ next:
if (async && *total_trimmed)
break;
if (fatal_signal_pending(current)) {
if (btrfs_trim_interrupted()) {
ret = -ERESTARTSYS;
break;
}
@ -4000,7 +4000,7 @@ next:
}
block_group->discard_cursor = start;
if (fatal_signal_pending(current)) {
if (btrfs_trim_interrupted()) {
if (start != offset)
reset_trimming_bitmap(ctl, offset);
ret = -ERESTARTSYS;

6
fs/btrfs/free-space-cache.h
View File

@ -10,6 +10,7 @@
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/freezer.h>
#include "fs.h"
struct inode;
@ -56,6 +57,11 @@ static inline bool btrfs_free_space_trimming_bitmap(
return (info->trim_state == BTRFS_TRIM_STATE_TRIMMING);
}
static inline bool btrfs_trim_interrupted(void)
{
return fatal_signal_pending(current) || freezing(current);
}
/*
* Deltas are an effective way to populate global statistics. Give macro names
* to make it clear what we're doing. An example is discard_extents in