Btrfs: remove all subvol options before mounting top-level

[firefly-linux-kernel-4.4.55.git] / fs / btrfs / super.c

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 9e66f5e724db1e307f19f74df7862550c170f069..1c57c0d0dc41ba723ec45d1f92ea5f30e88866df 100644 (file)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -135,6 +135,7 @@ static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
  * __btrfs_std_error decodes expected errors from the caller and
  * invokes the approciate error response.
  */
+__cold
 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
                       unsigned int line, int errno, const char *fmt, ...)
 {
@@ -247,18 +248,11 @@ void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
  * We'll complete the cleanup in btrfs_end_transaction and
  * btrfs_commit_transaction.
  */
+__cold
 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
                               struct btrfs_root *root, const char *function,
                               unsigned int line, int errno)
 {
-       /*
-        * Report first abort since mount
-        */
-       if (!test_and_set_bit(BTRFS_FS_STATE_TRANS_ABORTED,
-                               &root->fs_info->fs_state)) {
-               WARN(1, KERN_DEBUG "BTRFS: Transaction aborted (error %d)\n",
-                               errno);
-       }
        trans->aborted = errno;
        /* Nothing used. The other threads that have joined this
         * transaction may be able to continue. */
@@ -281,6 +275,7 @@ void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
  * __btrfs_panic decodes unexpected, fatal errors from the caller,
  * issues an alert, and either panics or BUGs, depending on mount options.
  */
+__cold
 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
                   unsigned int line, int errno, const char *fmt, ...)
 {
@@ -1138,52 +1133,36 @@ static inline int is_subvolume_inode(struct inode *inode)
 }
 
 /*
- * This will strip out the subvol=%s argument for an argument string and add
- * subvolid=0 to make sure we get the actual tree root for path walking to the
- * subvol we want.
+ * This will add subvolid=0 to the argument string while removing any subvol=
+ * and subvolid= arguments to make sure we get the top-level root for path
+ * walking to the subvol we want.
  */
 static char *setup_root_args(char *args)
 {
-       unsigned len = strlen(args) + 2 + 1;
-       char *src, *dst, *buf;
-
-       /*
-        * We need the same args as before, but with this substitution:
-        * s!subvol=[^,]+!subvolid=0!
-        *
-        * Since the replacement string is up to 2 bytes longer than the
-        * original, allocate strlen(args) + 2 + 1 bytes.
-        */
+       char *buf, *dst, *sep;
 
-       src = strstr(args, "subvol=");
-       /* This shouldn't happen, but just in case.. */
-       if (!src)
-               return NULL;
+       if (!args)
+               return kstrdup("subvolid=0", GFP_NOFS);
 
-       buf = dst = kmalloc(len, GFP_NOFS);
+       /* The worst case is that we add ",subvolid=0" to the end. */
+       buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
        if (!buf)
                return NULL;
 
-       /*
-        * If the subvol= arg is not at the start of the string,
-        * copy whatever precedes it into buf.
-        */
-       if (src != args) {
-               *src++ = '\0';
-               strcpy(buf, args);
-               dst += strlen(args);
+       while (1) {
+               sep = strchrnul(args, ',');
+               if (!strstarts(args, "subvol=") &&
+                   !strstarts(args, "subvolid=")) {
+                       memcpy(dst, args, sep - args);
+                       dst += sep - args;
+                       *dst++ = ',';
+               }
+               if (*sep)
+                       args = sep + 1;
+               else
+                       break;
        }
-
        strcpy(dst, "subvolid=0");
-       dst += strlen("subvolid=0");
-
-       /*
-        * If there is a "," after the original subvol=... string,
-        * copy that suffix into our buffer.  Otherwise, we're done.
-        */
-       src = strchr(src, ',');
-       if (src)
-               strcpy(dst, src);
 
        return buf;
 }
@@ -1214,7 +1193,9 @@ static struct dentry *mount_subvol(const char *subvol_name, int flags,
                                return ERR_CAST(mnt);
                        }
 
+                       down_write(&mnt->mnt_sb->s_umount);
                        r = btrfs_remount(mnt->mnt_sb, &flags, NULL);
+                       up_write(&mnt->mnt_sb->s_umount);
                        if (r < 0) {
                                /* FIXME: release vfsmount mnt ??*/
                                kfree(newargs);