On Mon 14-10-19 16:30:24, Eric Sandeen wrote:
> Anything that walks all inodes on sb->s_inodes list without rescheduling
> risks softlockups.
>
> Previous efforts were made in 2 functions, see:
>
> c27d82f fs/drop_caches.c: avoid softlockups in drop_pagecache_sb()
> ac05fbb inode: don't softlockup when evicting inodes
>
> but there hasn't been an audit of all walkers, so do that now. This
> also consistently moves the cond_resched() calls to the bottom of each
> loop in cases where it already exists.
>
> One loop remains: remove_dquot_ref(), because I'm not quite sure how
> to deal with that one w/o taking the i_lock.
>
> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
Thanks Eric. The patch looks good to me. You can add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
BTW, I suppose you need to add Al to pickup the patch?
Honza
> ---
>
> V2: Drop unrelated iput cleanups in fsnotify
>
> diff --git a/fs/drop_caches.c b/fs/drop_caches.c
> index d31b6c72b476..dc1a1d5d825b 100644
> --- a/fs/drop_caches.c
> +++ b/fs/drop_caches.c
> @@ -35,11 +35,11 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
> spin_unlock(&inode->i_lock);
> spin_unlock(&sb->s_inode_list_lock);
> - cond_resched();
> invalidate_mapping_pages(inode->i_mapping, 0, -1);
> iput(toput_inode);
> toput_inode = inode;
> + cond_resched();
> spin_lock(&sb->s_inode_list_lock);
> }
> spin_unlock(&sb->s_inode_list_lock);
> diff --git a/fs/inode.c b/fs/inode.c
> index fef457a42882..b0c789bb3dba 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -676,6 +676,7 @@ int invalidate_inodes(struct super_block *sb, bool kill_dirty)
> struct inode *inode, *next;
> LIST_HEAD(dispose);
> +again:
> spin_lock(&sb->s_inode_list_lock);
> list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
> spin_lock(&inode->i_lock);
> @@ -698,6 +699,13 @@ int invalidate_inodes(struct super_block *sb, bool kill_dirty)
> inode_lru_list_del(inode);
> spin_unlock(&inode->i_lock);
> list_add(&inode->i_lru, &dispose);
> +
> + if (need_resched()) {
> + spin_unlock(&sb->s_inode_list_lock);
> + cond_resched();
> + dispose_list(&dispose);
> + goto again;
> + }
> }
> spin_unlock(&sb->s_inode_list_lock);
> diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
> index 2ecef6155fc0..ac9eb273e28c 100644
> --- a/fs/notify/fsnotify.c
> +++ b/fs/notify/fsnotify.c
> @@ -77,6 +77,7 @@ static void fsnotify_unmount_inodes(struct super_block *sb)
> iput_inode = inode;
> + cond_resched();
> spin_lock(&sb->s_inode_list_lock);
> }
> spin_unlock(&sb->s_inode_list_lock);
> diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
> index 6e826b454082..4a085b3c7cac 100644
> --- a/fs/quota/dquot.c
> +++ b/fs/quota/dquot.c
> @@ -985,6 +985,7 @@ static int add_dquot_ref(struct super_block *sb, int type)
> * later.
> */
> old_inode = inode;
> + cond_resched();
> spin_lock(&sb->s_inode_list_lock);
> }
> spin_unlock(&sb->s_inode_list_lock);
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
