On Sat 13-03-21 11:01:44, zhangyi (F) wrote:
> block_dump is an old debugging interface, one of it's functions is used
> to print the information about who write which file on disk. If we
> enable block_dump through /proc/sys/vm/block_dump and turn on debug log
> level, we can gather information about write process name, target file
> name and disk from kernel message. This feature is realized in
> block_dump___mark_inode_dirty(), it print above information into kernel
> message directly when marking inode dirty, so it is noisy and can easily
> trigger log storm. At the same time, get the dentry refcount is also not
> safe, we found it will lead to deadlock on ext4 file system with
> data=journal mode.
>
> After tracepoints has been introduced into the kernel, we got a
> tracepoint in __mark_inode_dirty(), which is a better replacement of
> block_dump___mark_inode_dirty(). The only downside is that it only trace
> the inode number and not a file name, but it probably doesn't matter
> because the original printed file name in block_dump is not accurate in
> some cases, and we can still find it through the inode number and device
> id. So this patch delete the dirting inode part of block_dump feature.
>
> Signed-off-by: zhangyi (F) <yi.zhang@xxxxxxxxxx>
Looks good to me. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/fs-writeback.c | 25 -------------------------
> 1 file changed, 25 deletions(-)
>
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index e91980f49388..7c46d1588a19 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -2205,28 +2205,6 @@ int dirtytime_interval_handler(struct ctl_table *table, int write,
> return ret;
> }
>
> -static noinline void block_dump___mark_inode_dirty(struct inode *inode)
> -{
> - if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) {
> - struct dentry *dentry;
> - const char *name = "?";
> -
> - dentry = d_find_alias(inode);
> - if (dentry) {
> - spin_lock(&dentry->d_lock);
> - name = (const char *) dentry->d_name.name;
> - }
> - printk(KERN_DEBUG
> - "%s(%d): dirtied inode %lu (%s) on %s\n",
> - current->comm, task_pid_nr(current), inode->i_ino,
> - name, inode->i_sb->s_id);
> - if (dentry) {
> - spin_unlock(&dentry->d_lock);
> - dput(dentry);
> - }
> - }
> -}
> -
> /**
> * __mark_inode_dirty - internal function to mark an inode dirty
> *
> @@ -2296,9 +2274,6 @@ void __mark_inode_dirty(struct inode *inode, int flags)
> (dirtytime && (inode->i_state & I_DIRTY_INODE)))
> return;
>
> - if (unlikely(block_dump))
> - block_dump___mark_inode_dirty(inode);
> -
> spin_lock(&inode->i_lock);
> if (dirtytime && (inode->i_state & I_DIRTY_INODE))
> goto out_unlock_inode;
> --
> 2.25.4
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
