On Sun 05-06-22 15:38:13, Matthew Wilcox (Oracle) wrote:
> As described in commit 02117b8ae9c0 ("f2fs: Set GF_NOFS in
> read_cache_page_gfp while doing f2fs_quota_read"), we must not enter
> filesystem reclaim while holding the dq_lock. Prevent this more generally
> by using memalloc_nofs_save() while holding the lock.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
This is definitely a good cleanup to have and seems mostly unrelated to the
rest. I'll take it rightaway into my tree. Thanks for the patch!
Honza
> ---
> fs/quota/dquot.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
> index a74aef99bd3d..cdb22d6d7488 100644
> --- a/fs/quota/dquot.c
> +++ b/fs/quota/dquot.c
> @@ -425,9 +425,11 @@ EXPORT_SYMBOL(mark_info_dirty);
> int dquot_acquire(struct dquot *dquot)
> {
> int ret = 0, ret2 = 0;
> + unsigned int memalloc;
> struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
>
> mutex_lock(&dquot->dq_lock);
> + memalloc = memalloc_nofs_save();
> if (!test_bit(DQ_READ_B, &dquot->dq_flags)) {
> ret = dqopt->ops[dquot->dq_id.type]->read_dqblk(dquot);
> if (ret < 0)
> @@ -458,6 +460,7 @@ int dquot_acquire(struct dquot *dquot)
> smp_mb__before_atomic();
> set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
> out_iolock:
> + memalloc_nofs_restore(memalloc);
> mutex_unlock(&dquot->dq_lock);
> return ret;
> }
> @@ -469,9 +472,11 @@ EXPORT_SYMBOL(dquot_acquire);
> int dquot_commit(struct dquot *dquot)
> {
> int ret = 0;
> + unsigned int memalloc;
> struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
>
> mutex_lock(&dquot->dq_lock);
> + memalloc = memalloc_nofs_save();
> if (!clear_dquot_dirty(dquot))
> goto out_lock;
> /* Inactive dquot can be only if there was error during read/init
> @@ -481,6 +486,7 @@ int dquot_commit(struct dquot *dquot)
> else
> ret = -EIO;
> out_lock:
> + memalloc_nofs_restore(memalloc);
> mutex_unlock(&dquot->dq_lock);
> return ret;
> }
> @@ -492,9 +498,11 @@ EXPORT_SYMBOL(dquot_commit);
> int dquot_release(struct dquot *dquot)
> {
> int ret = 0, ret2 = 0;
> + unsigned int memalloc;
> struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
>
> mutex_lock(&dquot->dq_lock);
> + memalloc = memalloc_nofs_save();
> /* Check whether we are not racing with some other dqget() */
> if (dquot_is_busy(dquot))
> goto out_dqlock;
> @@ -510,6 +518,7 @@ int dquot_release(struct dquot *dquot)
> }
> clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
> out_dqlock:
> + memalloc_nofs_restore(memalloc);
> mutex_unlock(&dquot->dq_lock);
> return ret;
> }
> --
> 2.35.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
