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SubjectRe: [PATCH 6/8] exofs: super_operations and file_system_type
Hi.

On Mon, Feb 09, 2009 at 03:25:53PM +0200, Boaz Harrosh (bharrosh@panasas.com) wrote:
> +static int parse_options(char *options, struct exofs_mountopt *opts)
> +{
> + char *p;
> + substring_t args[MAX_OPT_ARGS];
> + int option;
> + bool s_pid = false;
> +
> + EXOFS_DBGMSG("parse_options %s\n", options);
> + /* defaults */
> + memset(opts, 0, sizeof(*opts));
> + opts->timeout = BLK_DEFAULT_SG_TIMEOUT;
> +
> + while ((p = strsep(&options, ",")) != NULL) {
> + int token;
> + char str[32];
> +
> + if (!*p)
> + continue;
> +
> + token = match_token(p, tokens, args);
> + switch (token) {
> + case Opt_pid:
> + if (0 == match_strlcpy(str, &args[0], sizeof(str)))
> + return -EINVAL;
> + opts->pid = simple_strtoull(str, NULL, 0);
> + if (opts->pid < EXOFS_MIN_PID) {
> + EXOFS_ERR("Partition ID must be >= %u",
> + EXOFS_MIN_PID);
> + return -EINVAL;
> + }
> + s_pid = 1;
> + break;
> + case Opt_to:
> + if (match_int(&args[0], &option))
> + return -EINVAL;
> + if (option <= 0) {
> + EXOFS_ERR("Timout must be > 0");
> + return -EINVAL;
> + }
> + opts->timeout = option * HZ;

Is it intentional to be a different timeouton systems with different HX
but the same mount option?

> +static struct inode *exofs_alloc_inode(struct super_block *sb)
> +{
> + struct exofs_i_info *oi;
> +
> + oi = kmem_cache_alloc(exofs_inode_cachep, GFP_KERNEL);

I'm curious if this should be GFP_NOFS or not?

> + if (!oi)
> + return NULL;
> +
> + oi->vfs_inode.i_version = 1;
> + return &oi->vfs_inode;
> +}

> +static void exofs_put_super(struct super_block *sb)
> +{
> + int num_pend;
> + struct exofs_sb_info *sbi = sb->s_fs_info;
> +
> + /* make sure there are no pending commands */
> + for (num_pend = atomic_read(&sbi->s_curr_pending); num_pend > 0;
> + num_pend = atomic_read(&sbi->s_curr_pending)) {

This rises a question. Let's check exofs_new_inode() for example (it is
a bad example, since inode can not be created when we already in the
put_super() callback, but still there are others), it increments
s_curr_pending way after inode was created, so is it possible that
some in-flight callback is about to be executed and its subsequent
s_curr_pending manipulation will not be detected by this loop?

Should s_curr_pending increment be audited all over the code to be
increased before the potential postponing command starts (which is not
the case in exofs_new_inode() above)?

> + wait_queue_head_t wq;
> + init_waitqueue_head(&wq);
> + wait_event_timeout(wq,
> + (atomic_read(&sbi->s_curr_pending) == 0),
> + msecs_to_jiffies(100));
> + }
> +
> + osduld_put_device(sbi->s_dev);
> + kfree(sb->s_fs_info);
> + sb->s_fs_info = NULL;
> +}

--
Evgeniy Polyakov


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