Hi Jun,
On 2017/12/7 19:30, piaojun wrote:
> CPUA CPUB
>
> ocfs2_dentry_convert_worker
> get 'l_lock'
This lock belongs to ocfs2_dentry_lock::ocfs2_lock_res::l_lock
>
> get 'dentry_attach_lock'
>
> interruptted by dio_end_io:
> dio_end_io
> dio_bio_end_aio
> dio_complete
> dio->end_io
> ocfs2_dio_end_io
> ocfs2_rw_unlock
> ...
> try to get 'l_lock'
This lock belongs to ocfs2_lock_res::l_lock though.
So I think they are totally two different locks.
So making spin_lock to interruption safe is pointless.
Thanks,
Changwei
> but CPUA has got it.
>
> try to get 'dentry_attach_lock',
> but CPUB has got 'dentry_attach_lock',
> and would not release it.
>
> so we need use spin_lock_irqsave for 'dentry_attach_lock' to prevent
> interruptted by softirq.
>
> Signed-off-by: Jun Piao <piao...@huawei.com>
> Reviewed-by: Alex Chen <alex.c...@huawei.com>
> ---
> fs/ocfs2/dcache.c | 14 ++++++++------
> fs/ocfs2/dlmglue.c | 14 +++++++-------
> fs/ocfs2/namei.c | 5 +++--
> 3 files changed, 18 insertions(+), 15 deletions(-)
>
> diff --git a/fs/ocfs2/dcache.c b/fs/ocfs2/dcache.c
> index 2903730..6555fbf 100644
> --- a/fs/ocfs2/dcache.c
> +++ b/fs/ocfs2/dcache.c
> @@ -230,6 +230,7 @@ int ocfs2_dentry_attach_lock(struct dentry *dentry,
> int ret;
> struct dentry *alias;
> struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
> + unsigned long flags;
>
> trace_ocfs2_dentry_attach_lock(dentry->d_name.len, dentry->d_name.name,
> (unsigned long long)parent_blkno, dl);
> @@ -309,10 +310,10 @@ int ocfs2_dentry_attach_lock(struct dentry *dentry,
> ocfs2_dentry_lock_res_init(dl, parent_blkno, inode);
>
> out_attach:
> - spin_lock(&dentry_attach_lock);
> + spin_lock_irqsave(&dentry_attach_lock, flags);
> dentry->d_fsdata = dl;
> dl->dl_count++;
> - spin_unlock(&dentry_attach_lock);
> + spin_unlock_irqrestore(&dentry_attach_lock, flags);
>
> /*
> * This actually gets us our PRMODE level lock. From now on,
> @@ -333,9 +334,9 @@ int ocfs2_dentry_attach_lock(struct dentry *dentry,
> if (ret < 0 && !alias) {
> ocfs2_lock_res_free(&dl->dl_lockres);
> BUG_ON(dl->dl_count != 1);
> - spin_lock(&dentry_attach_lock);
> + spin_lock_irqsave(&dentry_attach_lock, flags);
> dentry->d_fsdata = NULL;
> - spin_unlock(&dentry_attach_lock);
> + spin_unlock_irqrestore(&dentry_attach_lock, flags);
> kfree(dl);
> iput(inode);
> }
> @@ -379,13 +380,14 @@ void ocfs2_dentry_lock_put(struct ocfs2_super *osb,
> struct ocfs2_dentry_lock *dl)
> {
> int unlock = 0;
> + unsigned long flags;
>
> BUG_ON(dl->dl_count == 0);
>
> - spin_lock(&dentry_attach_lock);
> + spin_lock_irqsave(&dentry_attach_lock, flags);
> dl->dl_count--;
> unlock = !dl->dl_count;
> - spin_unlock(&dentry_attach_lock);
> + spin_unlock_irqrestore(&dentry_attach_lock, flags);
>
> if (unlock)
> ocfs2_drop_dentry_lock(osb, dl);
> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
> index 4689940..9bff3d2 100644
> --- a/fs/ocfs2/dlmglue.c
> +++ b/fs/ocfs2/dlmglue.c
> @@ -3801,7 +3801,7 @@ static int ocfs2_dentry_convert_worker(struct
> ocfs2_lock_res *lockres,
> struct ocfs2_dentry_lock *dl = ocfs2_lock_res_dl(lockres);
> struct ocfs2_inode_info *oi = OCFS2_I(dl->dl_inode);
> struct dentry *dentry;
> - unsigned long flags;
> + unsigned long flags, d_flags;
> int extra_ref = 0;
>
> /*
> @@ -3831,13 +3831,13 @@ static int ocfs2_dentry_convert_worker(struct
> ocfs2_lock_res *lockres,
> * flag.
> */
> spin_lock_irqsave(&lockres->l_lock, flags);
> - spin_lock(&dentry_attach_lock);
> + spin_lock_irqsave(&dentry_attach_lock, d_flags);
> if (!(lockres->l_flags & OCFS2_LOCK_FREEING)
> && dl->dl_count) {
> dl->dl_count++;
> extra_ref = 1;
> }
> - spin_unlock(&dentry_attach_lock);
> + spin_unlock_irqrestore(&dentry_attach_lock, d_flags);
> spin_unlock_irqrestore(&lockres->l_lock, flags);
>
> mlog(0, "extra_ref = %d\n", extra_ref);
> @@ -3850,13 +3850,13 @@ static int ocfs2_dentry_convert_worker(struct
> ocfs2_lock_res *lockres,
> if (!extra_ref)
> return UNBLOCK_CONTINUE;
>
> - spin_lock(&dentry_attach_lock);
> + spin_lock_irqsave(&dentry_attach_lock, d_flags);
> while (1) {
> dentry = ocfs2_find_local_alias(dl->dl_inode,
> dl->dl_parent_blkno, 1);
> if (!dentry)
> break;
> - spin_unlock(&dentry_attach_lock);
> + spin_unlock_irqrestore(&dentry_attach_lock, d_flags);
>
> if (S_ISDIR(dl->dl_inode->i_mode))
> shrink_dcache_parent(dentry);
> @@ -3874,9 +3874,9 @@ static int ocfs2_dentry_convert_worker(struct
> ocfs2_lock_res *lockres,
> d_delete(dentry);
> dput(dentry);
>
> - spin_lock(&dentry_attach_lock);
> + spin_lock_irqsave(&dentry_attach_lock, d_flags);
> }
> - spin_unlock(&dentry_attach_lock);
> + spin_unlock_irqrestore(&dentry_attach_lock, d_flags);
>
> /*
> * If we are the last holder of this dentry lock, there is no
> diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
> index 3b0a10d..a17454e 100644
> --- a/fs/ocfs2/namei.c
> +++ b/fs/ocfs2/namei.c
> @@ -223,13 +223,14 @@ static void ocfs2_cleanup_add_entry_failure(struct
> ocfs2_super *osb,
> struct dentry *dentry, struct inode *inode)
> {
> struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
> + unsigned long flags;
>
> ocfs2_simple_drop_lockres(osb, &dl->dl_lockres);
> ocfs2_lock_res_free(&dl->dl_lockres);
> BUG_ON(dl->dl_count != 1);
> - spin_lock(&dentry_attach_lock);
> + spin_lock_irqsave(&dentry_attach_lock, flags);
> dentry->d_fsdata = NULL;
> - spin_unlock(&dentry_attach_lock);
> + spin_unlock_irqrestore(&dentry_attach_lock, flags);
> kfree(dl);
> iput(inode);
> }
>
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