This pull request contains several UBIFS fixes. One of them fixes a race

condition between the mmap page fault path and fsync. Another just removes a
 bogus assertion from the UBIFS memory shrinker.
 
 UBIFS also started honoring the MS_SILENT mount flag, so now it won't print
 many I/O errors when user-space just tries to probe for the FS.
 
 Rest of the changes are rather minor UBI/UBIFS fixes, improvements, and
 clean-ups.
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Merge tag 'upstream-3.16-rc1-v2' of git://git.infradead.org/linux-ubifs

Pull UBIFS updates from Artem Bityutskiy:
 "This contains several UBIFS fixes.  One of them fixes a race condition
  between the mmap page fault path and fsync.  Another just removes a
  bogus assertion from the UBIFS memory shrinker.

  UBIFS also started honoring the MS_SILENT mount flag, so now it won't
  print many I/O errors when user-space just tries to probe for the FS.

  Rest of the changes are rather minor UBI/UBIFS fixes, improvements,
  and clean-ups"

* tag 'upstream-3.16-rc1-v2' of git://git.infradead.org/linux-ubifs:
  UBIFS: Add an assertion for clean_zn_cnt
  UBIFS: respect MS_SILENT mount flag
  UBIFS: Remove incorrect assertion in shrink_tnc()
  UBIFS: fix debugging check
  UBIFS: add missing ui pointer in debugging code
  UBI: block: Fix error path on alloc_workqueue failure
  UBIFS: Fix dump messages in ubifs_dump_lprops
  UBI: fix rb_tree node comparison in add_map
  UBIFS: Remove unused variables in ubifs_budget_space
  UBI: weaken the 'exclusive' constraint when opening volumes to rename
  UBIFS: fix an mmap and fsync race condition

drivers/mtd/ubi/block.c

@@ -432,8 +432,10 @@ int ubiblock_create(struct ubi_volume_info *vi)
 	 * Rembember workqueues are cheap, they're not threads.
 	 */
 	dev->wq = alloc_workqueue("%s", 0, 0, gd->disk_name);
-	if (!dev->wq)
+	if (!dev->wq) {
+		ret = -ENOMEM;
 		goto out_free_queue;
+	}
 	INIT_WORK(&dev->work, ubiblock_do_work);
 
 	mutex_lock(&devices_mutex);

drivers/mtd/ubi/cdev.c

@@ -731,7 +731,7 @@ static int rename_volumes(struct ubi_device *ubi,
 			goto out_free;
 		}
 
-		re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
+		re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_READWRITE);
 		if (IS_ERR(re->desc)) {
 			err = PTR_ERR(re->desc);
 			ubi_err("cannot open volume %d, error %d", vol_id, err);

drivers/mtd/ubi/fastmap.c

@@ -125,9 +125,9 @@ static struct ubi_ainf_volume *add_vol(struct ubi_attach_info *ai, int vol_id,
 		parent = *p;
 		av = rb_entry(parent, struct ubi_ainf_volume, rb);
 
-		if (vol_id > av->vol_id)
+		if (vol_id < av->vol_id)
 			p = &(*p)->rb_left;
-		else if (vol_id > av->vol_id)
+		else
 			p = &(*p)->rb_right;
 	}
 

fs/ubifs/budget.c

@@ -437,7 +437,6 @@ static int calc_dd_growth(const struct ubifs_info *c,
  */
 int ubifs_budget_space(struct ubifs_info *c, struct ubifs_budget_req *req)
 {
-	int uninitialized_var(cmt_retries), uninitialized_var(wb_retries);
 	int err, idx_growth, data_growth, dd_growth, retried = 0;
 
 	ubifs_assert(req->new_page <= 1);

fs/ubifs/debug.c

@@ -745,8 +745,10 @@ void ubifs_dump_lprops(struct ubifs_info *c)
 
 	for (lnum = c->main_first; lnum < c->leb_cnt; lnum++) {
 		err = ubifs_read_one_lp(c, lnum, &lp);
-		if (err)
+		if (err) {
 			ubifs_err("cannot read lprops for LEB %d", lnum);
+			continue;
+		}
 
 		ubifs_dump_lprop(c, &lp);
 	}

fs/ubifs/file.c

@@ -903,8 +903,9 @@ static int do_writepage(struct page *page, int len)
 	struct ubifs_info *c = inode->i_sb->s_fs_info;
 
 #ifdef UBIFS_DEBUG
+	struct ubifs_inode *ui = ubifs_inode(inode);
 	spin_lock(&ui->ui_lock);
-	ubifs_assert(page->index <= ui->synced_i_size << PAGE_CACHE_SIZE);
+	ubifs_assert(page->index <= ui->synced_i_size >> PAGE_CACHE_SHIFT);
 	spin_unlock(&ui->ui_lock);
 #endif
 
@@ -1525,8 +1526,7 @@ static int ubifs_vm_page_mkwrite(struct vm_area_struct *vma,
 	}
 
 	wait_for_stable_page(page);
-	unlock_page(page);
-	return 0;
+	return VM_FAULT_LOCKED;
 
 out_unlock:
 	unlock_page(page);

fs/ubifs/io.c

@@ -988,30 +988,32 @@ int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len,
 		return err;
 
 	if (type != ch->node_type) {
-		ubifs_err("bad node type (%d but expected %d)",
-			  ch->node_type, type);
+		ubifs_errc(c, "bad node type (%d but expected %d)",
+			   ch->node_type, type);
 		goto out;
 	}
 
 	err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
 	if (err) {
-		ubifs_err("expected node type %d", type);
+		ubifs_errc(c, "expected node type %d", type);
 		return err;
 	}
 
 	l = le32_to_cpu(ch->len);
 	if (l != len) {
-		ubifs_err("bad node length %d, expected %d", l, len);
+		ubifs_errc(c, "bad node length %d, expected %d", l, len);
 		goto out;
 	}
 
 	return 0;
 
 out:
-	ubifs_err("bad node at LEB %d:%d, LEB mapping status %d", lnum, offs,
-		  ubi_is_mapped(c->ubi, lnum));
-	ubifs_dump_node(c, buf);
-	dump_stack();
+	ubifs_errc(c, "bad node at LEB %d:%d, LEB mapping status %d", lnum,
+		   offs, ubi_is_mapped(c->ubi, lnum));
+	if (!c->probing) {
+		ubifs_dump_node(c, buf);
+		dump_stack();
+	}
 	return -EINVAL;
 }
 

fs/ubifs/shrinker.c

@@ -128,7 +128,6 @@ static int shrink_tnc(struct ubifs_info *c, int nr, int age, int *contention)
 			freed = ubifs_destroy_tnc_subtree(znode);
 			atomic_long_sub(freed, &ubifs_clean_zn_cnt);
 			atomic_long_sub(freed, &c->clean_zn_cnt);
-			ubifs_assert(atomic_long_read(&c->clean_zn_cnt) >= 0);
 			total_freed += freed;
 			znode = zprev;
 		}

fs/ubifs/super.c

@@ -1149,6 +1149,9 @@ static int mount_ubifs(struct ubifs_info *c)
 	size_t sz;
 
 	c->ro_mount = !!(c->vfs_sb->s_flags & MS_RDONLY);
+	/* Suppress error messages while probing if MS_SILENT is set */
+	c->probing = !!(c->vfs_sb->s_flags & MS_SILENT);
+
 	err = init_constants_early(c);
 	if (err)
 		return err;
@@ -1214,6 +1217,8 @@ static int mount_ubifs(struct ubifs_info *c)
 	if (err)
 		goto out_free;
 
+	c->probing = 0;
+
 	/*
 	 * Make sure the compressor which is set as default in the superblock
 	 * or overridden by mount options is actually compiled in.

fs/ubifs/tnc.c

@@ -2859,10 +2859,11 @@ void ubifs_tnc_close(struct ubifs_info *c)
 {
 	tnc_destroy_cnext(c);
 	if (c->zroot.znode) {
-		long n;
+		long n, freed;
 
-		ubifs_destroy_tnc_subtree(c->zroot.znode);
 		n = atomic_long_read(&c->clean_zn_cnt);
+		freed = ubifs_destroy_tnc_subtree(c->zroot.znode);
+		ubifs_assert(freed == n);
 		atomic_long_sub(n, &ubifs_clean_zn_cnt);
 	}
 	kfree(c->gap_lebs);

fs/ubifs/ubifs.h

@@ -51,6 +51,15 @@
 #define ubifs_warn(fmt, ...)                                        \
 	pr_warn("UBIFS warning (pid %d): %s: " fmt "\n",            \
 		current->pid, __func__, ##__VA_ARGS__)
+/*
+ * A variant of 'ubifs_err()' which takes the UBIFS file-sytem description
+ * object as an argument.
+ */
+#define ubifs_errc(c, fmt, ...)                                     \
+	do {                                                        \
+		if (!(c)->probing)                                  \
+			ubifs_err(fmt, ##__VA_ARGS__);              \
+	} while (0)
 
 /* UBIFS file system VFS magic number */
 #define UBIFS_SUPER_MAGIC 0x24051905
@@ -1209,6 +1218,7 @@ struct ubifs_debug_info;
  * @need_recovery: %1 if the file-system needs recovery
  * @replaying: %1 during journal replay
  * @mounting: %1 while mounting
+ * @probing: %1 while attempting to mount if MS_SILENT mount flag is set
  * @remounting_rw: %1 while re-mounting from R/O mode to R/W mode
  * @replay_list: temporary list used during journal replay
  * @replay_buds: list of buds to replay
@@ -1441,6 +1451,7 @@ struct ubifs_info {
 	unsigned int replaying:1;
 	unsigned int mounting:1;
 	unsigned int remounting_rw:1;
+	unsigned int probing:1;
 	struct list_head replay_list;
 	struct list_head replay_buds;
 	unsigned long long cs_sqnum;