Commit bf2069d1 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag '6.6-rc5-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6 

Pull smb client fixes from Steve French:

 - fix caching race with open_cached_dir and laundromat cleanup of
   cached dirs (addresses a problem spotted with xfstest run with
   directory leases enabled)

 - reduce excessive resource usage of laundromat threads

* tag '6.6-rc5-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  smb: client: prevent new fids from being removed by laundromat
  smb: client: make laundromat a delayed worker
parents dc9b2e68 81ba1095

fs/smb/client/cached_dir.c

+68 −73
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
static struct cached_fid *init_cached_dir(const char *path);

static void free_cached_dir(struct cached_fid *cfid);

static void smb2_close_cached_fid(struct kref *ref);

static void cfids_laundromat_worker(struct work_struct *work);



static struct cached_fid *find_or_create_cached_dir(struct cached_fids *cfids,

						    const char *path,
@@ -169,15 +170,18 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, 
		return -ENOENT;

	}

	/*

	 * At this point we either have a lease already and we can just

	 * return it. If not we are guaranteed to be the only thread accessing

	 * this cfid.

	 * Return cached fid if it has a lease.  Otherwise, it is either a new

	 * entry or laundromat worker removed it from @cfids->entries.  Caller

	 * will put last reference if the latter.

	 */

	spin_lock(&cfids->cfid_list_lock);

	if (cfid->has_lease) {

		spin_unlock(&cfids->cfid_list_lock);

		*ret_cfid = cfid;

		kfree(utf16_path);

		return 0;

	}

	spin_unlock(&cfids->cfid_list_lock);



	/*

	 * Skip any prefix paths in @path as lookup_positive_unlocked() ends up
@@ -294,9 +298,11 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, 
			goto oshr_free;

		}

	}

	spin_lock(&cfids->cfid_list_lock);

	cfid->dentry = dentry;

	cfid->time = jiffies;

	cfid->has_lease = true;

	spin_unlock(&cfids->cfid_list_lock);



oshr_free:

	kfree(utf16_path);
@@ -305,24 +311,28 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, 
	free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base);

	free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);

	spin_lock(&cfids->cfid_list_lock);

	if (rc && !cfid->has_lease) {

	if (!cfid->has_lease) {

		if (rc) {

			if (cfid->on_list) {

				list_del(&cfid->entry);

				cfid->on_list = false;

				cfids->num_entries--;

			}

			rc = -ENOENT;

	}

	spin_unlock(&cfids->cfid_list_lock);

	if (!rc && !cfid->has_lease) {

		} else {

			/*

		 * We are guaranteed to have two references at this point.

		 * One for the caller and one for a potential lease.

		 * Release the Lease-ref so that the directory will be closed

		 * when the caller closes the cached handle.

			 * We are guaranteed to have two references at this

			 * point. One for the caller and one for a potential

			 * lease. Release the Lease-ref so that the directory

			 * will be closed when the caller closes the cached

			 * handle.

			 */

			spin_unlock(&cfids->cfid_list_lock);

			kref_put(&cfid->refcount, smb2_close_cached_fid);

			goto out;

		}

	}

	spin_unlock(&cfids->cfid_list_lock);

	if (rc) {

		if (cfid->is_open)

			SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid,
@@ -330,7 +340,7 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, 
		free_cached_dir(cfid);

		cfid = NULL;

	}



out:

	if (rc == 0) {

		*ret_cfid = cfid;

		atomic_inc(&tcon->num_remote_opens);
@@ -572,53 +582,51 @@ static void free_cached_dir(struct cached_fid *cfid) 
	kfree(cfid);

}



static int

cifs_cfids_laundromat_thread(void *p)

static void cfids_laundromat_worker(struct work_struct *work)

{

	struct cached_fids *cfids = p;

	struct cached_fids *cfids;

	struct cached_fid *cfid, *q;

	struct list_head entry;

	LIST_HEAD(entry);



	cfids = container_of(work, struct cached_fids, laundromat_work.work);



	while (!kthread_should_stop()) {

		ssleep(1);

		INIT_LIST_HEAD(&entry);

		if (kthread_should_stop())

			return 0;

	spin_lock(&cfids->cfid_list_lock);

	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {

			if (time_after(jiffies, cfid->time + HZ * dir_cache_timeout)) {

				list_del(&cfid->entry);

				list_add(&cfid->entry, &entry);

		if (cfid->time &&

		    time_after(jiffies, cfid->time + HZ * dir_cache_timeout)) {

			cfid->on_list = false;

			list_move(&cfid->entry, &entry);

			cfids->num_entries--;

			/* To prevent race with smb2_cached_lease_break() */

			kref_get(&cfid->refcount);

		}

	}

	spin_unlock(&cfids->cfid_list_lock);



	list_for_each_entry_safe(cfid, q, &entry, entry) {

			cfid->on_list = false;

		list_del(&cfid->entry);

		/*

			 * Cancel, and wait for the work to finish in

			 * case we are racing with it.

		 * Cancel and wait for the work to finish in case we are racing

		 * with it.

		 */

		cancel_work_sync(&cfid->lease_break);

		if (cfid->has_lease) {

			/*

				 * We lease has not yet been cancelled from

				 * the server so we need to drop the reference.

			 * Our lease has not yet been cancelled from the server

			 * so we need to drop the reference.

			 */

			spin_lock(&cfids->cfid_list_lock);

			cfid->has_lease = false;

			spin_unlock(&cfids->cfid_list_lock);

			kref_put(&cfid->refcount, smb2_close_cached_fid);

		}

		/* Drop the extra reference opened above */

		kref_put(&cfid->refcount, smb2_close_cached_fid);

	}

	queue_delayed_work(cifsiod_wq, &cfids->laundromat_work,

			   dir_cache_timeout * HZ);

}



	return 0;

}





struct cached_fids *init_cached_dirs(void)

{

	struct cached_fids *cfids;
@@ -629,19 +637,10 @@ struct cached_fids *init_cached_dirs(void) 
	spin_lock_init(&cfids->cfid_list_lock);

	INIT_LIST_HEAD(&cfids->entries);



	/*

	 * since we're in a cifs function already, we know that

	 * this will succeed. No need for try_module_get().

	 */

	__module_get(THIS_MODULE);

	cfids->laundromat = kthread_run(cifs_cfids_laundromat_thread,

				  cfids, "cifsd-cfid-laundromat");

	if (IS_ERR(cfids->laundromat)) {

		cifs_dbg(VFS, "Failed to start cfids laundromat thread.\n");

		kfree(cfids);

		module_put(THIS_MODULE);

		return NULL;

	}

	INIT_DELAYED_WORK(&cfids->laundromat_work, cfids_laundromat_worker);

	queue_delayed_work(cifsiod_wq, &cfids->laundromat_work,

			   dir_cache_timeout * HZ);



	return cfids;

}
@@ -657,11 +656,7 @@ void free_cached_dirs(struct cached_fids *cfids) 
	if (cfids == NULL)

		return;



	if (cfids->laundromat) {

		kthread_stop(cfids->laundromat);

		cfids->laundromat = NULL;

		module_put(THIS_MODULE);

	}

	cancel_delayed_work_sync(&cfids->laundromat_work);



	spin_lock(&cfids->cfid_list_lock);

	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {

fs/smb/client/cached_dir.h

+1 −1
Original line number Diff line number Diff line
@@ -57,7 +57,7 @@ struct cached_fids { 
	spinlock_t cfid_list_lock;

	int num_entries;

	struct list_head entries;

	struct task_struct *laundromat;

	struct delayed_work laundromat_work;

};



extern struct cached_fids *init_cached_dirs(void);