Re: [PATCH v4 3/3] btrfs: Don't block system suspend during fstrim

[Luca Stefani]

On 16/09/24 12:41, Qu Wenruo wrote:
> 在 2024/9/16 19:46, Luca Stefani 写道:
> > Sometimes the system isn't able to suspend 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, and there is no
> > limits on the trim size (unlike the block group part).
> >
> > Since discard 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 failure.
> >
> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=219180
> > Link: https://bugzilla.suse.com/show_bug.cgi?id=1229737
> > Signed-off-by: Luca Stefani <luca.stefani.ge1@xxxxxxxxx>
> > ---
> >   fs/btrfs/extent-tree.c | 19 ++++++++++++++++++-
> >   1 file changed, 18 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> > index cbe66d0acff8..ab2e5d366a3a 100644
> > --- a/fs/btrfs/extent-tree.c
> > +++ b/fs/btrfs/extent-tree.c
> > @@ -16,6 +16,7 @@
> >   #include <linux/percpu_counter.h>
> >   #include <linux/lockdep.h>
> >   #include <linux/crc32c.h>
> > +#include <linux/freezer.h>
> >   #include "ctree.h"
> >   #include "extent-tree.h"
> >   #include "transaction.h"
> > @@ -1235,6 +1236,11 @@ static int remove_extent_backref(struct 
> > btrfs_trans_handle *trans,
> >       return ret;
> >   }
> > +static bool btrfs_trim_interrupted(void)
> > +{
> > +    return fatal_signal_pending(current) || freezing(current);
> > +}
> > +
> >   static int btrfs_issue_discard(struct block_device *bdev, u64 start, 
> > u64 len,
> >                      u64 *discarded_bytes)
> >   {
> > @@ -1319,6 +1325,11 @@ 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;
> > @@ -6473,7 +6484,7 @@ 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;
> >           }
> > @@ -6522,6 +6533,9 @@ int btrfs_trim_fs(struct btrfs_fs_info *fs_info, 
> > struct fstrim_range *range)
> >       cache = btrfs_lookup_first_block_group(fs_info, range->start);
> >       for (; cache; cache = btrfs_next_block_group(cache)) {
> > +        if (btrfs_trim_interrupted())
> > +            break;
> > +
>
> Please update @bg_ret return value.
Done in v5.
> >           if (cache->start >= range_end) {
> >               btrfs_put_block_group(cache);
> >               break;
> > @@ -6561,6 +6575,9 @@ int btrfs_trim_fs(struct btrfs_fs_info *fs_info, 
> > struct fstrim_range *range)
> >       mutex_lock(&fs_devices->device_list_mutex);
> >       list_for_each_entry(device, &fs_devices->devices, dev_list) {
> > +        if (btrfs_trim_interrupted())
> > +            break;
> > +
>
> The same here, please update @dev_ret.
ditto.
> Thanks,
> Qu
> >           if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state))
> >               continue;