Merge branch 'foreign/qu/norecovery-v7' into for-chris-4.6

4 files changed, 67 insertions, 18 deletions

diff --git a/Documentation/filesystems/btrfs.txt b/Documentation/filesystems/btrfs.txt
index c772b47e7ef0..6593d2e415c5 100644
--- a/Documentation/filesystems/btrfs.txt
+++ b/Documentation/filesystems/btrfs.txt
@@ -168,10 +168,23 @@ Options with (*) are default options and will not show in the mount options.
   notreelog
         Enable/disable the tree logging used for fsync and O_SYNC writes.
 
-  recovery
-        Enable autorecovery attempts if a bad tree root is found at mount time.
-        Currently this scans a list of several previous tree roots and tries to
+  nologreplay
+        Disable the log tree replay at mount time to prevent filesystem
+        from getting modified.
+        Must be used with 'ro' mount option.
+        A filesystem mounted with this option cannot transition to a
+        read-write mount via remount,rw - the filesystem must be unmounted
+        and mounted back again if read-write access is desired.
+
+  usebackuproot
+        Enable attempts to use backup tree roots if a bad tree root is found at
+        mount time.
+        Currently this scans a list of 4 previous tree roots and tries to
         use the first readable.
+        And since the mount option doesn't affect any behavior after mount,
+        it won't be shown in mount info.
+        Prior to 4.6, this was done by 'recovery' option that has been
+        deprecated, but will work.
 
   rescan_uuid_tree
         Force check and rebuild procedure of the UUID tree. This should not
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 3fb3b787aa5e..6af1211d4ee9 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2274,7 +2274,7 @@ struct btrfs_ioctl_defrag_range_args {
 #define BTRFS_MOUNT_ENOSPC_DEBUG         (1 << 15)
 #define BTRFS_MOUNT_AUTO_DEFRAG         (1 << 16)
 #define BTRFS_MOUNT_INODE_MAP_CACHE     (1 << 17)
-#define BTRFS_MOUNT_RECOVERY            (1 << 18)
+#define BTRFS_MOUNT_USEBACKUPROOT       (1 << 18)
 #define BTRFS_MOUNT_SKIP_BALANCE        (1 << 19)
 #define BTRFS_MOUNT_CHECK_INTEGRITY     (1 << 20)
 #define BTRFS_MOUNT_CHECK_INTEGRITY_INCLUDING_EXTENT_DATA (1 << 21)
@@ -2283,6 +2283,7 @@ struct btrfs_ioctl_defrag_range_args {
 #define BTRFS_MOUNT_FRAGMENT_DATA       (1 << 24)
 #define BTRFS_MOUNT_FRAGMENT_METADATA   (1 << 25)
 #define BTRFS_MOUNT_FREE_SPACE_TREE     (1 << 26)
+#define BTRFS_MOUNT_NOLOGREPLAY         (1 << 27)
 
 #define BTRFS_DEFAULT_COMMIT_INTERVAL   (30)
 #define BTRFS_DEFAULT_MAX_INLINE        (8192)
@@ -4187,7 +4188,8 @@ void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info);
 ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size);
 
 /* super.c */
-int btrfs_parse_options(struct btrfs_root *root, char *options);
+int btrfs_parse_options(struct btrfs_root *root, char *options,
+                        unsigned long new_flags);
 int btrfs_sync_fs(struct super_block *sb, int wait);
 
 #ifdef CONFIG_PRINTK
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 40690e90beee..294c77729df3 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2751,7 +2751,7 @@ int open_ctree(struct super_block *sb,
          */
         fs_info->compress_type = BTRFS_COMPRESS_ZLIB;
 
-        ret = btrfs_parse_options(tree_root, options);
+        ret = btrfs_parse_options(tree_root, options, sb->s_flags);
         if (ret) {
                 err = ret;
                 goto fail_alloc;
@@ -3030,8 +3030,9 @@ retry_root_backup:
         if (ret)
                 goto fail_trans_kthread;
 
-        /* do not make disk changes in broken FS */
-        if (btrfs_super_log_root(disk_super) != 0) {
+        /* do not make disk changes in broken FS or nologreplay is given */
+        if (btrfs_super_log_root(disk_super) != 0 &&
+            !btrfs_test_opt(tree_root, NOLOGREPLAY)) {
                 ret = btrfs_replay_log(fs_info, fs_devices);
                 if (ret) {
                         err = ret;
@@ -3147,6 +3148,12 @@ retry_root_backup:
 
         fs_info->open = 1;
 
+        /*
+         * backuproot only affect mount behavior, and if open_ctree succeeded,
+         * no need to keep the flag
+         */
+        btrfs_clear_opt(fs_info->mount_opt, USEBACKUPROOT);
+
         return 0;
 
 fail_qgroup:
@@ -3201,7 +3208,7 @@ fail:
         return err;
 
 recovery_tree_root:
-        if (!btrfs_test_opt(tree_root, RECOVERY))
+        if (!btrfs_test_opt(tree_root, USEBACKUPROOT))
                 goto fail_tree_roots;
 
         free_root_pointers(fs_info, 0);
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index d41e09fe8e38..bf75200c6f86 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -303,7 +303,8 @@ enum {
         Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
         Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
         Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
-        Opt_datasum, Opt_treelog, Opt_noinode_cache,
+        Opt_datasum, Opt_treelog, Opt_noinode_cache, Opt_usebackuproot,
+        Opt_nologreplay, Opt_norecovery,
 #ifdef CONFIG_BTRFS_DEBUG
         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 #endif
@@ -335,6 +336,8 @@ static const match_table_t tokens = {
         {Opt_noacl, "noacl"},
         {Opt_notreelog, "notreelog"},
         {Opt_treelog, "treelog"},
+        {Opt_nologreplay, "nologreplay"},
+        {Opt_norecovery, "norecovery"},
         {Opt_flushoncommit, "flushoncommit"},
         {Opt_noflushoncommit, "noflushoncommit"},
         {Opt_ratio, "metadata_ratio=%d"},
@@ -352,7 +355,8 @@ static const match_table_t tokens = {
         {Opt_inode_cache, "inode_cache"},
         {Opt_noinode_cache, "noinode_cache"},
         {Opt_no_space_cache, "nospace_cache"},
-        {Opt_recovery, "recovery"},
+        {Opt_recovery, "recovery"}, /* deprecated */
+        {Opt_usebackuproot, "usebackuproot"},
         {Opt_skip_balance, "skip_balance"},
         {Opt_check_integrity, "check_int"},
         {Opt_check_integrity_including_extent_data, "check_int_data"},
@@ -373,7 +377,8 @@ static const match_table_t tokens = {
  * reading in a new superblock is parsed here.
  * XXX JDM: This needs to be cleaned up for remount.
  */
-int btrfs_parse_options(struct btrfs_root *root, char *options)
+int btrfs_parse_options(struct btrfs_root *root, char *options,
+                        unsigned long new_flags)
 {
         struct btrfs_fs_info *info = root->fs_info;
         substring_t args[MAX_OPT_ARGS];
@@ -393,8 +398,12 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
         else if (cache_gen)
                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 
+        /*
+         * Even the options are empty, we still need to do extra check
+         * against new flags
+         */
         if (!options)
-                goto out;
+                goto check;
 
         /*
          * strsep changes the string, duplicate it because parse_options
@@ -606,6 +615,11 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                         btrfs_clear_and_info(root, NOTREELOG,
                                              "enabling tree log");
                         break;
+                case Opt_norecovery:
+                case Opt_nologreplay:
+                        btrfs_set_and_info(root, NOLOGREPLAY,
+                                           "disabling log replay at mount time");
+                        break;
                 case Opt_flushoncommit:
                         btrfs_set_and_info(root, FLUSHONCOMMIT,
                                            "turning on flush-on-commit");
@@ -696,8 +710,12 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                                              "disabling auto defrag");
                         break;
                 case Opt_recovery:
-                        btrfs_info(root->fs_info, "enabling auto recovery");
-                        btrfs_set_opt(info->mount_opt, RECOVERY);
+                        btrfs_warn(root->fs_info,
+                                   "'recovery' is deprecated, use 'usebackuproot' instead");
+                case Opt_usebackuproot:
+                        btrfs_info(root->fs_info,
+                                   "trying to use backup root at mount time");
+                        btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
                         break;
                 case Opt_skip_balance:
                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
@@ -792,6 +810,15 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                         break;
                 }
         }
+check:
+        /*
+         * Extra check for current option against current flag
+         */
+        if (btrfs_test_opt(root, NOLOGREPLAY) && !(new_flags & MS_RDONLY)) {
+                btrfs_err(root->fs_info,
+                          "nologreplay must be used with ro mount option");
+                ret = -EINVAL;
+        }
 out:
         if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE) &&
             !btrfs_test_opt(root, FREE_SPACE_TREE) &&
@@ -1202,6 +1229,8 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
                 seq_puts(seq, ",ssd");
         if (btrfs_test_opt(root, NOTREELOG))
                 seq_puts(seq, ",notreelog");
+        if (btrfs_test_opt(root, NOLOGREPLAY))
+                seq_puts(seq, ",nologreplay");
         if (btrfs_test_opt(root, FLUSHONCOMMIT))
                 seq_puts(seq, ",flushoncommit");
         if (btrfs_test_opt(root, DISCARD))
@@ -1228,8 +1257,6 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
                 seq_puts(seq, ",inode_cache");
         if (btrfs_test_opt(root, SKIP_BALANCE))
                 seq_puts(seq, ",skip_balance");
-        if (btrfs_test_opt(root, RECOVERY))
-                seq_puts(seq, ",recovery");
 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
         if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
                 seq_puts(seq, ",check_int_data");
@@ -1685,7 +1712,7 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data)
                 }
         }
 
-        ret = btrfs_parse_options(root, data);
+        ret = btrfs_parse_options(root, data, *flags);
         if (ret) {
                 ret = -EINVAL;
                 goto restore;