On Sun 07-05-23 18:19:25, Luis Chamberlain wrote:
> The kernel power management now supports allowing the VFS
> to handle filesystem freezing freezes and thawing. Take advantage
> of that and remove the kthread freezing. This is needed so that we
> properly really stop IO in flight without races after userspace
> has been frozen. Without this we rely on kthread freezing and
> its semantics are loose and error prone.
>
> The filesystem therefore is in charge of properly dealing with
> quiescing of the filesystem through its callbacks if it thinks
> it knows better than how the VFS handles it.
>
> The following Coccinelle rule was used as to remove the now superfluous
> freezer calls:
>
> make coccicheck MODE=patch SPFLAGS="--in-place --no-show-diff" COCCI=./fs-freeze-cleanup.cocci M=fs/ext4
>
> virtual patch
>
> @ remove_set_freezable @
> expression time;
> statement S, S2;
> expression task, current;
> @@
>
> (
> - set_freezable();
> |
> - if (try_to_freeze())
> - continue;
> |
> - try_to_freeze();
> |
> - freezable_schedule();
> + schedule();
> |
> - freezable_schedule_timeout(time);
> + schedule_timeout(time);
> |
> - if (freezing(task)) { S }
> |
> - if (freezing(task)) { S }
> - else
> { S2 }
> |
> - freezing(current)
> )
>
> @ remove_wq_freezable @
> expression WQ_E, WQ_ARG1, WQ_ARG2, WQ_ARG3, WQ_ARG4;
> identifier fs_wq_fn;
> @@
>
> (
> WQ_E = alloc_workqueue(WQ_ARG1,
> - WQ_ARG2 | WQ_FREEZABLE,
> + WQ_ARG2,
> ...);
> |
> WQ_E = alloc_workqueue(WQ_ARG1,
> - WQ_ARG2 | WQ_FREEZABLE | WQ_ARG3,
> + WQ_ARG2 | WQ_ARG3,
> ...);
> |
> WQ_E = alloc_workqueue(WQ_ARG1,
> - WQ_ARG2 | WQ_ARG3 | WQ_FREEZABLE,
> + WQ_ARG2 | WQ_ARG3,
> ...);
> |
> WQ_E = alloc_workqueue(WQ_ARG1,
> - WQ_ARG2 | WQ_ARG3 | WQ_FREEZABLE | WQ_ARG4,
> + WQ_ARG2 | WQ_ARG3 | WQ_ARG4,
> ...);
> |
> WQ_E =
> - WQ_ARG1 | WQ_FREEZABLE
> + WQ_ARG1
> |
> WQ_E =
> - WQ_ARG1 | WQ_FREEZABLE | WQ_ARG3
> + WQ_ARG1 | WQ_ARG3
> |
> fs_wq_fn(
> - WQ_FREEZABLE | WQ_ARG2 | WQ_ARG3
> + WQ_ARG2 | WQ_ARG3
> )
> |
> fs_wq_fn(
> - WQ_FREEZABLE | WQ_ARG2
> + WQ_ARG2
> )
> |
> fs_wq_fn(
> - WQ_FREEZABLE
> + 0
> )
> )
>
> @ add_auto_flag @
> expression E1;
> identifier fs_type;
> @@
>
> struct file_system_type fs_type = {
> .fs_flags = E1
> + | FS_AUTOFREEZE
> ,
> };
>
> Generated-by: Coccinelle SmPL
> Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
I guess we can also usually remove the #include <linux/freezer.h> line? At
least in ext4 it is the case I believe. Otherwise this looks good.
Honza
> ---
> fs/ext4/super.c | 9 +++------
> 1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index d39f386e9baf..1f436938d8be 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -136,7 +136,7 @@ static struct file_system_type ext2_fs_type = {
> .init_fs_context = ext4_init_fs_context,
> .parameters = ext4_param_specs,
> .kill_sb = kill_block_super,
> - .fs_flags = FS_REQUIRES_DEV,
> + .fs_flags = FS_REQUIRES_DEV | FS_AUTOFREEZE,
> };
> MODULE_ALIAS_FS("ext2");
> MODULE_ALIAS("ext2");
> @@ -152,7 +152,7 @@ static struct file_system_type ext3_fs_type = {
> .init_fs_context = ext4_init_fs_context,
> .parameters = ext4_param_specs,
> .kill_sb = kill_block_super,
> - .fs_flags = FS_REQUIRES_DEV,
> + .fs_flags = FS_REQUIRES_DEV | FS_AUTOFREEZE,
> };
> MODULE_ALIAS_FS("ext3");
> MODULE_ALIAS("ext3");
> @@ -3790,7 +3790,6 @@ static int ext4_lazyinit_thread(void *arg)
> unsigned long next_wakeup, cur;
>
> BUG_ON(NULL == eli);
> - set_freezable();
>
> cont_thread:
> while (true) {
> @@ -3842,8 +3841,6 @@ static int ext4_lazyinit_thread(void *arg)
> }
> mutex_unlock(&eli->li_list_mtx);
>
> - try_to_freeze();
> -
> cur = jiffies;
> if ((time_after_eq(cur, next_wakeup)) ||
> (MAX_JIFFY_OFFSET == next_wakeup)) {
> @@ -7245,7 +7242,7 @@ static struct file_system_type ext4_fs_type = {
> .init_fs_context = ext4_init_fs_context,
> .parameters = ext4_param_specs,
> .kill_sb = kill_block_super,
> - .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
> + .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP | FS_AUTOFREEZE,
> };
> MODULE_ALIAS_FS("ext4");
>
> --
> 2.39.2
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
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