From bdabe8562d42aee1c59189027a6f8b2d949e6f9e Mon Sep 17 00:00:00 2001
From: Stefan Behrens <sbehrens@giantdisaster.de>
Date: Tue, 30 Oct 2012 17:16:16 +0000
Subject: [PATCH] --- yaml --- r: 346656 b: refs/heads/master c:
 292fd7fc39aa06668f3a8db546714e727120cb3e h: refs/heads/master v: v3

---
 [refs]                   | 2 +-
 trunk/fs/btrfs/disk-io.c | 7 +++++++
 trunk/fs/btrfs/super.c   | 9 +++++++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index e497c6d4fdd2..1c5aa86d625e 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d1423248734df6d9aff769abffd675dc034e0601
+refs/heads/master: 292fd7fc39aa06668f3a8db546714e727120cb3e
diff --git a/trunk/fs/btrfs/disk-io.c b/trunk/fs/btrfs/disk-io.c
index bd70c2852ba0..064315990f8a 100644
--- a/trunk/fs/btrfs/disk-io.c
+++ b/trunk/fs/btrfs/disk-io.c
@@ -2508,6 +2508,13 @@ int open_ctree(struct super_block *sb,
 	}
 	fs_info->num_tolerated_disk_barrier_failures =
 		btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
+	if (fs_info->fs_devices->missing_devices >
+	     fs_info->num_tolerated_disk_barrier_failures &&
+	    !(sb->s_flags & MS_RDONLY)) {
+		printk(KERN_WARNING
+		       "Btrfs: too many missing devices, writeable mount is not allowed\n");
+		goto fail_block_groups;
+	}
 
 	fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
 					       "btrfs-cleaner");
diff --git a/trunk/fs/btrfs/super.c b/trunk/fs/btrfs/super.c
index 915ac14c2064..acd2df85bed5 100644
--- a/trunk/fs/btrfs/super.c
+++ b/trunk/fs/btrfs/super.c
@@ -1226,6 +1226,15 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data)
 			goto restore;
 		}
 
+		if (fs_info->fs_devices->missing_devices >
+		     fs_info->num_tolerated_disk_barrier_failures &&
+		    !(*flags & MS_RDONLY)) {
+			printk(KERN_WARNING
+			       "Btrfs: too many missing devices, writeable remount is not allowed\n");
+			ret = -EACCES;
+			goto restore;
+		}
+
 		if (btrfs_super_log_root(fs_info->super_copy) != 0) {
 			ret = -EINVAL;
 			goto restore;