1 files changed, 196 insertions, 119 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 15634d4648d7..e28ad4baf483 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -40,6 +40,7 @@
 #include <linux/magic.h>
 #include <linux/slab.h>
 #include <linux/cleancache.h>
+#include <linux/mnt_namespace.h>
 #include "compat.h"
 #include "delayed-inode.h"
 #include "ctree.h"
@@ -58,6 +59,7 @@
 #include <trace/events/btrfs.h>
 
 static const struct super_operations btrfs_super_ops;
+static struct file_system_type btrfs_fs_type;
 
 static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno,
                                       char nbuf[16])
@@ -162,7 +164,7 @@ enum {
         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
         Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
         Opt_enospc_debug, Opt_subvolrootid, Opt_defrag,
-        Opt_inode_cache, Opt_err,
+        Opt_inode_cache, Opt_no_space_cache, Opt_recovery, Opt_err,
 };
 
 static match_table_t tokens = {
@@ -195,6 +197,8 @@ static match_table_t tokens = {
         {Opt_subvolrootid, "subvolrootid=%d"},
         {Opt_defrag, "autodefrag"},
         {Opt_inode_cache, "inode_cache"},
+        {Opt_no_space_cache, "nospace_cache"},
+        {Opt_recovery, "recovery"},
         {Opt_err, NULL},
 };
 
@@ -206,14 +210,19 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
 {
         struct btrfs_fs_info *info = root->fs_info;
         substring_t args[MAX_OPT_ARGS];
-        char *p, *num, *orig;
+        char *p, *num, *orig = NULL;
+        u64 cache_gen;
         int intarg;
         int ret = 0;
         char *compress_type;
         bool compress_force = false;
 
+        cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
+        if (cache_gen)
+                btrfs_set_opt(info->mount_opt, SPACE_CACHE);
+
         if (!options)
-                return 0;
+                goto out;
 
         /*
          * strsep changes the string, duplicate it because parse_options
@@ -360,9 +369,12 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                         btrfs_set_opt(info->mount_opt, DISCARD);
                         break;
                 case Opt_space_cache:
-                        printk(KERN_INFO "btrfs: enabling disk space caching\n");
                         btrfs_set_opt(info->mount_opt, SPACE_CACHE);
                         break;
+                case Opt_no_space_cache:
+                        printk(KERN_INFO "btrfs: disabling disk space caching\n");
+                        btrfs_clear_opt(info->mount_opt, SPACE_CACHE);
+                        break;
                 case Opt_inode_cache:
                         printk(KERN_INFO "btrfs: enabling inode map caching\n");
                         btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE);
@@ -381,6 +393,10 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                         printk(KERN_INFO "btrfs: enabling auto defrag");
                         btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
                         break;
+                case Opt_recovery:
+                        printk(KERN_INFO "btrfs: enabling auto recovery");
+                        btrfs_set_opt(info->mount_opt, RECOVERY);
+                        break;
                 case Opt_err:
                         printk(KERN_INFO "btrfs: unrecognized mount option "
                                "'%s'\n", p);
@@ -391,6 +407,8 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                 }
         }
 out:
+        if (!ret && btrfs_test_opt(root, SPACE_CACHE))
+                printk(KERN_INFO "btrfs: disk space caching is enabled\n");
         kfree(orig);
         return ret;
 }
@@ -406,12 +424,12 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags,
                 u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
 {
         substring_t args[MAX_OPT_ARGS];
-        char *opts, *orig, *p;
+        char *device_name, *opts, *orig, *p;
         int error = 0;
         int intarg;
 
         if (!options)
-                goto out;
+                return 0;
 
         /*
          * strsep changes the string, duplicate it because parse_options
@@ -430,6 +448,7 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags,
                 token = match_token(p, tokens, args);
                 switch (token) {
                 case Opt_subvol:
+                        kfree(*subvol_name);
                         *subvol_name = match_strdup(&args[0]);
                         break;
                 case Opt_subvolid:
@@ -457,29 +476,24 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags,
                         }
                         break;
                 case Opt_device:
-                        error = btrfs_scan_one_device(match_strdup(&args[0]),
+                        device_name = match_strdup(&args[0]);
+                        if (!device_name) {
+                                error = -ENOMEM;
+                                goto out;
+                        }
+                        error = btrfs_scan_one_device(device_name,
                                         flags, holder, fs_devices);
+                        kfree(device_name);
                         if (error)
-                                goto out_free_opts;
+                                goto out;
                         break;
                 default:
                         break;
                 }
         }
 
- out_free_opts:
+out:
         kfree(orig);
- out:
-        /*
-         * If no subvolume name is specified we use the default one.  Allocate
-         * a copy of the string "." here so that code later in the
-         * mount path doesn't care if it's the default volume or another one.
-         */
-        if (!*subvol_name) {
-                *subvol_name = kstrdup(".", GFP_KERNEL);
-                if (!*subvol_name)
-                        return -ENOMEM;
-        }
         return error;
 }
 
@@ -492,7 +506,6 @@ static struct dentry *get_default_root(struct super_block *sb,
         struct btrfs_path *path;
         struct btrfs_key location;
         struct inode *inode;
-        struct dentry *dentry;
         u64 dir_id;
         int new = 0;
 
@@ -517,7 +530,7 @@ static struct dentry *get_default_root(struct super_block *sb,
          * will mount by default if we haven't been given a specific subvolume
          * to mount.
          */
-        dir_id = btrfs_super_root_dir(&root->fs_info->super_copy);
+        dir_id = btrfs_super_root_dir(root->fs_info->super_copy);
         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
         if (IS_ERR(di)) {
                 btrfs_free_path(path);
@@ -566,29 +579,7 @@ setup_root:
                 return dget(sb->s_root);
         }
 
-        if (new) {
-                const struct qstr name = { .name = "/", .len = 1 };
-
-                /*
-                 * New inode, we need to make the dentry a sibling of s_root so
-                 * everything gets cleaned up properly on unmount.
-                 */
-                dentry = d_alloc(sb->s_root, &name);
-                if (!dentry) {
-                        iput(inode);
-                        return ERR_PTR(-ENOMEM);
-                }
-                d_splice_alias(inode, dentry);
-        } else {
-                /*
-                 * We found the inode in cache, just find a dentry for it and
-                 * put the reference to the inode we just got.
-                 */
-                dentry = d_find_alias(inode);
-                iput(inode);
-        }
-
-        return dentry;
+        return d_obtain_alias(inode);
 }
 
 static int btrfs_fill_super(struct super_block *sb,
@@ -719,6 +710,8 @@ static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
                 seq_puts(seq, ",noacl");
         if (btrfs_test_opt(root, SPACE_CACHE))
                 seq_puts(seq, ",space_cache");
+        else
+                seq_puts(seq, ",nospace_cache");
         if (btrfs_test_opt(root, CLEAR_CACHE))
                 seq_puts(seq, ",clear_cache");
         if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
@@ -753,6 +746,111 @@ static int btrfs_set_super(struct super_block *s, void *data)
         return set_anon_super(s, data);
 }
 
+/*
+ * subvolumes are identified by ino 256
+ */
+static inline int is_subvolume_inode(struct inode *inode)
+{
+        if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
+                return 1;
+        return 0;
+}
+
+/*
+ * 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.
+ */
+static char *setup_root_args(char *args)
+{
+        unsigned copied = 0;
+        unsigned len = strlen(args) + 2;
+        char *pos;
+        char *ret;
+
+        /*
+         * We need the same args as before, but minus
+         *
+         * subvol=a
+         *
+         * and add
+         *
+         * subvolid=0
+         *
+         * which is a difference of 2 characters, so we allocate strlen(args) +
+         * 2 characters.
+         */
+        ret = kzalloc(len * sizeof(char), GFP_NOFS);
+        if (!ret)
+                return NULL;
+        pos = strstr(args, "subvol=");
+
+        /* This shouldn't happen, but just in case.. */
+        if (!pos) {
+                kfree(ret);
+                return NULL;
+        }
+
+        /*
+         * The subvol=<> arg is not at the front of the string, copy everybody
+         * up to that into ret.
+         */
+        if (pos != args) {
+                *pos = '\0';
+                strcpy(ret, args);
+                copied += strlen(args);
+                pos++;
+        }
+
+        strncpy(ret + copied, "subvolid=0", len - copied);
+
+        /* Length of subvolid=0 */
+        copied += 10;
+
+        /*
+         * If there is no , after the subvol= option then we know there's no
+         * other options and we can just return.
+         */
+        pos = strchr(pos, ',');
+        if (!pos)
+                return ret;
+
+        /* Copy the rest of the arguments into our buffer */
+        strncpy(ret + copied, pos, len - copied);
+        copied += strlen(pos);
+
+        return ret;
+}
+
+static struct dentry *mount_subvol(const char *subvol_name, int flags,
+                                   const char *device_name, char *data)
+{
+        struct dentry *root;
+        struct vfsmount *mnt;
+        char *newargs;
+
+        newargs = setup_root_args(data);
+        if (!newargs)
+                return ERR_PTR(-ENOMEM);
+        mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
+                             newargs);
+        kfree(newargs);
+        if (IS_ERR(mnt))
+                return ERR_CAST(mnt);
+
+        root = mount_subtree(mnt, subvol_name);
+
+        if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) {
+                struct super_block *s = root->d_sb;
+                dput(root);
+                root = ERR_PTR(-EINVAL);
+                deactivate_locked_super(s);
+                printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
+                                subvol_name);
+        }
+
+        return root;
+}
 
 /*
  * Find a superblock for the given device / mount point.
@@ -767,7 +865,6 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
         struct super_block *s;
         struct dentry *root;
         struct btrfs_fs_devices *fs_devices = NULL;
-        struct btrfs_root *tree_root = NULL;
         struct btrfs_fs_info *fs_info = NULL;
         fmode_t mode = FMODE_READ;
         char *subvol_name = NULL;
@@ -781,21 +878,20 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
         error = btrfs_parse_early_options(data, mode, fs_type,
                                           &subvol_name, &subvol_objectid,
                                           &subvol_rootid, &fs_devices);
-        if (error)
+        if (error) {
+                kfree(subvol_name);
                 return ERR_PTR(error);
+        }
 
-        error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
-        if (error)
-                goto error_free_subvol_name;
+        if (subvol_name) {
+                root = mount_subvol(subvol_name, flags, device_name, data);
+                kfree(subvol_name);
+                return root;
+        }
 
-        error = btrfs_open_devices(fs_devices, mode, fs_type);
+        error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
         if (error)
-                goto error_free_subvol_name;
-
-        if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
-                error = -EACCES;
-                goto error_close_devices;
-        }
+                return ERR_PTR(error);
 
         /*
          * Setup a dummy root and fs_info for test/set super.  This is because
@@ -804,19 +900,40 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
          * then open_ctree will properly initialize everything later.
          */
         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
-        tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
-        if (!fs_info || !tree_root) {
+        if (!fs_info)
+                return ERR_PTR(-ENOMEM);
+
+        fs_info->tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
+        if (!fs_info->tree_root) {
                 error = -ENOMEM;
-                goto error_close_devices;
+                goto error_fs_info;
         }
-        fs_info->tree_root = tree_root;
+        fs_info->tree_root->fs_info = fs_info;
         fs_info->fs_devices = fs_devices;
-        tree_root->fs_info = fs_info;
+
+        fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
+        fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
+        if (!fs_info->super_copy || !fs_info->super_for_commit) {
+                error = -ENOMEM;
+                goto error_fs_info;
+        }
+
+        error = btrfs_open_devices(fs_devices, mode, fs_type);
+        if (error)
+                goto error_fs_info;
+
+        if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
+                error = -EACCES;
+                goto error_close_devices;
+        }
 
         bdev = fs_devices->latest_bdev;
-        s = sget(fs_type, btrfs_test_super, btrfs_set_super, tree_root);
-        if (IS_ERR(s))
-                goto error_s;
+        s = sget(fs_type, btrfs_test_super, btrfs_set_super,
+                 fs_info->tree_root);
+        if (IS_ERR(s)) {
+                error = PTR_ERR(s);
+                goto error_close_devices;
+        }
 
         if (s->s_root) {
                 if ((flags ^ s->s_flags) & MS_RDONLY) {
@@ -826,75 +943,35 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
                 }
 
                 btrfs_close_devices(fs_devices);
-                kfree(fs_info);
-                kfree(tree_root);
+                free_fs_info(fs_info);
         } else {
                 char b[BDEVNAME_SIZE];
 
                 s->s_flags = flags | MS_NOSEC;
                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
+                btrfs_sb(s)->fs_info->bdev_holder = fs_type;
                 error = btrfs_fill_super(s, fs_devices, data,
                                          flags & MS_SILENT ? 1 : 0);
                 if (error) {
                         deactivate_locked_super(s);
-                        goto error_free_subvol_name;
+                        return ERR_PTR(error);
                 }
 
-                btrfs_sb(s)->fs_info->bdev_holder = fs_type;
                 s->s_flags |= MS_ACTIVE;
         }
 
-        /* if they gave us a subvolume name bind mount into that */
-        if (strcmp(subvol_name, ".")) {
-                struct dentry *new_root;
-
-                root = get_default_root(s, subvol_rootid);
-                if (IS_ERR(root)) {
-                        error = PTR_ERR(root);
-                        deactivate_locked_super(s);
-                        goto error_free_subvol_name;
-                }
-
-                mutex_lock(&root->d_inode->i_mutex);
-                new_root = lookup_one_len(subvol_name, root,
-                                      strlen(subvol_name));
-                mutex_unlock(&root->d_inode->i_mutex);
-
-                if (IS_ERR(new_root)) {
-                        dput(root);
-                        deactivate_locked_super(s);
-                        error = PTR_ERR(new_root);
-                        goto error_free_subvol_name;
-                }
-                if (!new_root->d_inode) {
-                        dput(root);
-                        dput(new_root);
-                        deactivate_locked_super(s);
-                        error = -ENXIO;
-                        goto error_free_subvol_name;
-                }
-                dput(root);
-                root = new_root;
-        } else {
-                root = get_default_root(s, subvol_objectid);
-                if (IS_ERR(root)) {
-                        error = PTR_ERR(root);
-                        deactivate_locked_super(s);
-                        goto error_free_subvol_name;
-                }
+        root = get_default_root(s, subvol_objectid);
+        if (IS_ERR(root)) {
+                deactivate_locked_super(s);
+                return root;
         }
 
-        kfree(subvol_name);
         return root;
 
-error_s:
-        error = PTR_ERR(s);
 error_close_devices:
         btrfs_close_devices(fs_devices);
-        kfree(fs_info);
-        kfree(tree_root);
-error_free_subvol_name:
-        kfree(subvol_name);
+error_fs_info:
+        free_fs_info(fs_info);
         return ERR_PTR(error);
 }
 
@@ -919,7 +996,7 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data)
                 if (root->fs_info->fs_devices->rw_devices == 0)
                         return -EACCES;
 
-                if (btrfs_super_log_root(&root->fs_info->super_copy) != 0)
+                if (btrfs_super_log_root(root->fs_info->super_copy) != 0)
                         return -EINVAL;
 
                 ret = btrfs_cleanup_fs_roots(root->fs_info);
@@ -980,7 +1057,7 @@ static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
         int i = 0, nr_devices;
         int ret;
 
-        nr_devices = fs_info->fs_devices->rw_devices;
+        nr_devices = fs_info->fs_devices->open_devices;
         BUG_ON(!nr_devices);
 
         devices_info = kmalloc(sizeof(*devices_info) * nr_devices,
@@ -1002,8 +1079,8 @@ static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
         else
                 min_stripe_size = BTRFS_STRIPE_LEN;
 
-        list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
-                if (!device->in_fs_metadata)
+        list_for_each_entry(device, &fs_devices->devices, dev_list) {
+                if (!device->in_fs_metadata || !device->bdev)
                         continue;
 
                 avail_space = device->total_bytes - device->bytes_used;
@@ -1085,7 +1162,7 @@ static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
-        struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
+        struct btrfs_super_block *disk_super = root->fs_info->super_copy;
         struct list_head *head = &root->fs_info->space_info;
         struct btrfs_space_info *found;
         u64 total_used = 0;