1 files changed, 286 insertions, 117 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 4b4516770f05..2c02310ff2d9 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -42,12 +42,12 @@
 #include <linux/slab.h>
 #include <linux/blkdev.h>
 #include <linux/uuid.h>
+#include <linux/btrfs.h>
 #include "compat.h"
 #include "ctree.h"
 #include "disk-io.h"
 #include "transaction.h"
 #include "btrfs_inode.h"
-#include "ioctl.h"
 #include "print-tree.h"
 #include "volumes.h"
 #include "locking.h"
@@ -152,7 +152,7 @@ void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
 
 static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
 {
-        struct btrfs_inode *ip = BTRFS_I(file->f_path.dentry->d_inode);
+        struct btrfs_inode *ip = BTRFS_I(file_inode(file));
         unsigned int flags = btrfs_flags_to_ioctl(ip->flags);
 
         if (copy_to_user(arg, &flags, sizeof(flags)))
@@ -177,7 +177,7 @@ static int check_flags(unsigned int flags)
 
 static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 {
-        struct inode *inode = file->f_path.dentry->d_inode;
+        struct inode *inode = file_inode(file);
         struct btrfs_inode *ip = BTRFS_I(inode);
         struct btrfs_root *root = ip->root;
         struct btrfs_trans_handle *trans;
@@ -310,7 +310,7 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 
 static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
 {
-        struct inode *inode = file->f_path.dentry->d_inode;
+        struct inode *inode = file_inode(file);
 
         return put_user(inode->i_generation, arg);
 }
@@ -363,46 +363,52 @@ static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
         return 0;
 }
 
-static noinline int create_subvol(struct btrfs_root *root,
+static noinline int create_subvol(struct inode *dir,
                                   struct dentry *dentry,
                                   char *name, int namelen,
                                   u64 *async_transid,
-                                  struct btrfs_qgroup_inherit **inherit)
+                                  struct btrfs_qgroup_inherit *inherit)
 {
         struct btrfs_trans_handle *trans;
         struct btrfs_key key;
         struct btrfs_root_item root_item;
         struct btrfs_inode_item *inode_item;
         struct extent_buffer *leaf;
+        struct btrfs_root *root = BTRFS_I(dir)->root;
         struct btrfs_root *new_root;
-        struct dentry *parent = dentry->d_parent;
-        struct inode *dir;
+        struct btrfs_block_rsv block_rsv;
         struct timespec cur_time = CURRENT_TIME;
         int ret;
         int err;
         u64 objectid;
         u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
         u64 index = 0;
+        u64 qgroup_reserved;
         uuid_le new_uuid;
 
         ret = btrfs_find_free_objectid(root->fs_info->tree_root, &objectid);
         if (ret)
                 return ret;
 
-        dir = parent->d_inode;
-
+        btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
         /*
-         * 1 - inode item
-         * 2 - refs
-         * 1 - root item
-         * 2 - dir items
+         * The same as the snapshot creation, please see the comment
+         * of create_snapshot().
          */
-        trans = btrfs_start_transaction(root, 6);
-        if (IS_ERR(trans))
-                return PTR_ERR(trans);
+        ret = btrfs_subvolume_reserve_metadata(root, &block_rsv,
+                                               7, &qgroup_reserved);
+        if (ret)
+                return ret;
+
+        trans = btrfs_start_transaction(root, 0);
+        if (IS_ERR(trans)) {
+                ret = PTR_ERR(trans);
+                goto out;
+        }
+        trans->block_rsv = &block_rsv;
+        trans->bytes_reserved = block_rsv.size;
 
-        ret = btrfs_qgroup_inherit(trans, root->fs_info, 0, objectid,
-                                   inherit ? *inherit : NULL);
+        ret = btrfs_qgroup_inherit(trans, root->fs_info, 0, objectid, inherit);
         if (ret)
                 goto fail;
 
@@ -515,22 +521,31 @@ static noinline int create_subvol(struct btrfs_root *root,
 
         BUG_ON(ret);
 
-        d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry));
 fail:
+        trans->block_rsv = NULL;
+        trans->bytes_reserved = 0;
         if (async_transid) {
                 *async_transid = trans->transid;
                 err = btrfs_commit_transaction_async(trans, root, 1);
+                if (err)
+                        err = btrfs_commit_transaction(trans, root);
         } else {
                 err = btrfs_commit_transaction(trans, root);
         }
         if (err && !ret)
                 ret = err;
+
+        if (!ret)
+                d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry));
+out:
+        btrfs_subvolume_release_metadata(root, &block_rsv, qgroup_reserved);
         return ret;
 }
 
-static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
-                           char *name, int namelen, u64 *async_transid,
-                           bool readonly, struct btrfs_qgroup_inherit **inherit)
+static int create_snapshot(struct btrfs_root *root, struct inode *dir,
+                           struct dentry *dentry, char *name, int namelen,
+                           u64 *async_transid, bool readonly,
+                           struct btrfs_qgroup_inherit *inherit)
 {
         struct inode *inode;
         struct btrfs_pending_snapshot *pending_snapshot;
@@ -546,23 +561,31 @@ static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
 
         btrfs_init_block_rsv(&pending_snapshot->block_rsv,
                              BTRFS_BLOCK_RSV_TEMP);
+        /*
+         * 1 - parent dir inode
+         * 2 - dir entries
+         * 1 - root item
+         * 2 - root ref/backref
+         * 1 - root of snapshot
+         */
+        ret = btrfs_subvolume_reserve_metadata(BTRFS_I(dir)->root,
+                                        &pending_snapshot->block_rsv, 7,
+                                        &pending_snapshot->qgroup_reserved);
+        if (ret)
+                goto out;
+
         pending_snapshot->dentry = dentry;
         pending_snapshot->root = root;
         pending_snapshot->readonly = readonly;
-        if (inherit) {
-                pending_snapshot->inherit = *inherit;
-                *inherit = NULL;        /* take responsibility to free it */
-        }
+        pending_snapshot->dir = dir;
+        pending_snapshot->inherit = inherit;
 
-        trans = btrfs_start_transaction(root->fs_info->extent_root, 6);
+        trans = btrfs_start_transaction(root, 0);
         if (IS_ERR(trans)) {
                 ret = PTR_ERR(trans);
                 goto fail;
         }
 
-        ret = btrfs_snap_reserve_metadata(trans, pending_snapshot);
-        BUG_ON(ret);
-
         spin_lock(&root->fs_info->trans_lock);
         list_add(&pending_snapshot->list,
                  &trans->transaction->pending_snapshots);
@@ -571,16 +594,14 @@ static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
                 *async_transid = trans->transid;
                 ret = btrfs_commit_transaction_async(trans,
                                      root->fs_info->extent_root, 1);
+                if (ret)
+                        ret = btrfs_commit_transaction(trans, root);
         } else {
                 ret = btrfs_commit_transaction(trans,
                                                root->fs_info->extent_root);
         }
-        if (ret) {
-                /* cleanup_transaction has freed this for us */
-                if (trans->aborted)
-                        pending_snapshot = NULL;
+        if (ret)
                 goto fail;
-        }
 
         ret = pending_snapshot->error;
         if (ret)
@@ -599,6 +620,10 @@ static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
         d_instantiate(dentry, inode);
         ret = 0;
 fail:
+        btrfs_subvolume_release_metadata(BTRFS_I(dir)->root,
+                                         &pending_snapshot->block_rsv,
+                                         pending_snapshot->qgroup_reserved);
+out:
         kfree(pending_snapshot);
         return ret;
 }
@@ -692,7 +717,7 @@ static noinline int btrfs_mksubvol(struct path *parent,
                                    char *name, int namelen,
                                    struct btrfs_root *snap_src,
                                    u64 *async_transid, bool readonly,
-                                   struct btrfs_qgroup_inherit **inherit)
+                                   struct btrfs_qgroup_inherit *inherit)
 {
         struct inode *dir  = parent->dentry->d_inode;
         struct dentry *dentry;
@@ -729,11 +754,11 @@ static noinline int btrfs_mksubvol(struct path *parent,
                 goto out_up_read;
 
         if (snap_src) {
-                error = create_snapshot(snap_src, dentry, name, namelen,
+                error = create_snapshot(snap_src, dir, dentry, name, namelen,
                                         async_transid, readonly, inherit);
         } else {
-                error = create_subvol(BTRFS_I(dir)->root, dentry,
-                                      name, namelen, async_transid, inherit);
+                error = create_subvol(dir, dentry, name, namelen,
+                                      async_transid, inherit);
         }
         if (!error)
                 fsnotify_mkdir(dir, dentry);
@@ -815,7 +840,7 @@ static int find_new_extents(struct btrfs_root *root,
 
         while(1) {
                 ret = btrfs_search_forward(root, &min_key, &max_key,
-                                           path, 0, newer_than);
+                                           path, newer_than);
                 if (ret != 0)
                         goto none;
                 if (min_key.objectid != ino)
@@ -1203,6 +1228,12 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
                 if (!(inode->i_sb->s_flags & MS_ACTIVE))
                         break;
 
+                if (btrfs_defrag_cancelled(root->fs_info)) {
+                        printk(KERN_DEBUG "btrfs: defrag_file cancelled\n");
+                        ret = -EAGAIN;
+                        break;
+                }
+
                 if (!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT,
                                          extent_thresh, &last_len, &skip,
                                          &defrag_end, range->flags &
@@ -1317,7 +1348,7 @@ static noinline int btrfs_ioctl_resize(struct file *file,
         u64 new_size;
         u64 old_size;
         u64 devid = 1;
-        struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
+        struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
         struct btrfs_ioctl_vol_args *vol_args;
         struct btrfs_trans_handle *trans;
         struct btrfs_device *device = NULL;
@@ -1326,9 +1357,6 @@ static noinline int btrfs_ioctl_resize(struct file *file,
         int ret = 0;
         int mod = 0;
 
-        if (root->fs_info->sb->s_flags & MS_RDONLY)
-                return -EROFS;
-
         if (!capable(CAP_SYS_ADMIN))
                 return -EPERM;
 
@@ -1339,7 +1367,8 @@ static noinline int btrfs_ioctl_resize(struct file *file,
         if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
                         1)) {
                 pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");
-                return -EINPROGRESS;
+                mnt_drop_write_file(file);
+                return -EINVAL;
         }
 
         mutex_lock(&root->fs_info->volume_mutex);
@@ -1359,21 +1388,27 @@ static noinline int btrfs_ioctl_resize(struct file *file,
                 *devstr = '\0';
                 devstr = vol_args->name;
                 devid = simple_strtoull(devstr, &end, 10);
+                if (!devid) {
+                        ret = -EINVAL;
+                        goto out_free;
+                }
                 printk(KERN_INFO "btrfs: resizing devid %llu\n",
                        (unsigned long long)devid);
         }
+
         device = btrfs_find_device(root->fs_info, devid, NULL, NULL);
         if (!device) {
                 printk(KERN_INFO "btrfs: resizer unable to find device %llu\n",
                        (unsigned long long)devid);
-                ret = -EINVAL;
+                ret = -ENODEV;
                 goto out_free;
         }
-        if (device->fs_devices && device->fs_devices->seeding) {
+
+        if (!device->writeable) {
                 printk(KERN_INFO "btrfs: resizer unable to apply on "
-                       "seeding device %llu\n",
+                       "readonly device %llu\n",
                        (unsigned long long)devid);
-                ret = -EINVAL;
+                ret = -EPERM;
                 goto out_free;
         }
 
@@ -1395,7 +1430,7 @@ static noinline int btrfs_ioctl_resize(struct file *file,
         }
 
         if (device->is_tgtdev_for_dev_replace) {
-                ret = -EINVAL;
+                ret = -EPERM;
                 goto out_free;
         }
 
@@ -1443,15 +1478,15 @@ out_free:
         kfree(vol_args);
 out:
         mutex_unlock(&root->fs_info->volume_mutex);
-        mnt_drop_write_file(file);
         atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
+        mnt_drop_write_file(file);
         return ret;
 }
 
 static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
                                 char *name, unsigned long fd, int subvol,
                                 u64 *transid, bool readonly,
-                                struct btrfs_qgroup_inherit **inherit)
+                                struct btrfs_qgroup_inherit *inherit)
 {
         int namelen;
         int ret = 0;
@@ -1483,8 +1518,8 @@ static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
                         goto out_drop_write;
                 }
 
-                src_inode = src.file->f_path.dentry->d_inode;
-                if (src_inode->i_sb != file->f_path.dentry->d_inode->i_sb) {
+                src_inode = file_inode(src.file);
+                if (src_inode->i_sb != file_inode(file)->i_sb) {
                         printk(KERN_INFO "btrfs: Snapshot src from "
                                "another FS\n");
                         ret = -EINVAL;
@@ -1560,7 +1595,7 @@ static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
 
         ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
                                               vol_args->fd, subvol, ptr,
-                                              readonly, &inherit);
+                                              readonly, inherit);
 
         if (ret == 0 && ptr &&
             copy_to_user(arg +
@@ -1576,7 +1611,7 @@ out:
 static noinline int btrfs_ioctl_subvol_getflags(struct file *file,
                                                 void __user *arg)
 {
-        struct inode *inode = fdentry(file)->d_inode;
+        struct inode *inode = file_inode(file);
         struct btrfs_root *root = BTRFS_I(inode)->root;
         int ret = 0;
         u64 flags = 0;
@@ -1598,7 +1633,7 @@ static noinline int btrfs_ioctl_subvol_getflags(struct file *file,
 static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
                                               void __user *arg)
 {
-        struct inode *inode = fdentry(file)->d_inode;
+        struct inode *inode = file_inode(file);
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_trans_handle *trans;
         u64 root_flags;
@@ -1857,7 +1892,7 @@ static noinline int search_ioctl(struct inode *inode,
         path->keep_locks = 1;
 
         while(1) {
-                ret = btrfs_search_forward(root, &key, &max_key, path, 0,
+                ret = btrfs_search_forward(root, &key, &max_key, path,
                                            sk->min_transid);
                 if (ret != 0) {
                         if (ret > 0)
@@ -1892,7 +1927,7 @@ static noinline int btrfs_ioctl_tree_search(struct file *file,
         if (IS_ERR(args))
                 return PTR_ERR(args);
 
-        inode = fdentry(file)->d_inode;
+        inode = file_inode(file);
         ret = search_ioctl(inode, args);
         if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
                 ret = -EFAULT;
@@ -2002,7 +2037,7 @@ static noinline int btrfs_ioctl_ino_lookup(struct file *file,
         if (IS_ERR(args))
                 return PTR_ERR(args);
 
-        inode = fdentry(file)->d_inode;
+        inode = file_inode(file);
 
         if (args->treeid == 0)
                 args->treeid = BTRFS_I(inode)->root->root_key.objectid;
@@ -2029,6 +2064,8 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file,
         struct btrfs_root *dest = NULL;
         struct btrfs_ioctl_vol_args *vol_args;
         struct btrfs_trans_handle *trans;
+        struct btrfs_block_rsv block_rsv;
+        u64 qgroup_reserved;
         int namelen;
         int ret;
         int err = 0;
@@ -2095,13 +2132,13 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file,
                 err = inode_permission(inode, MAY_WRITE | MAY_EXEC);
                 if (err)
                         goto out_dput;
-
-                /* check if subvolume may be deleted by a non-root user */
-                err = btrfs_may_delete(dir, dentry, 1);
-                if (err)
-                        goto out_dput;
         }
 
+        /* check if subvolume may be deleted by a user */
+        err = btrfs_may_delete(dir, dentry, 1);
+        if (err)
+                goto out_dput;
+
         if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) {
                 err = -EINVAL;
                 goto out_dput;
@@ -2118,12 +2155,23 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file,
         if (err)
                 goto out_up_write;
 
+        btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
+        /*
+         * One for dir inode, two for dir entries, two for root
+         * ref/backref.
+         */
+        err = btrfs_subvolume_reserve_metadata(root, &block_rsv,
+                                               5, &qgroup_reserved);
+        if (err)
+                goto out_up_write;
+
         trans = btrfs_start_transaction(root, 0);
         if (IS_ERR(trans)) {
                 err = PTR_ERR(trans);
-                goto out_up_write;
+                goto out_release;
         }
-        trans->block_rsv = &root->fs_info->global_block_rsv;
+        trans->block_rsv = &block_rsv;
+        trans->bytes_reserved = block_rsv.size;
 
         ret = btrfs_unlink_subvol(trans, root, dir,
                                 dest->root_key.objectid,
@@ -2153,10 +2201,14 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file,
                 }
         }
 out_end_trans:
+        trans->block_rsv = NULL;
+        trans->bytes_reserved = 0;
         ret = btrfs_end_transaction(trans, root);
         if (ret && !err)
                 err = ret;
         inode->i_flags |= S_DEAD;
+out_release:
+        btrfs_subvolume_release_metadata(root, &block_rsv, qgroup_reserved);
 out_up_write:
         up_write(&root->fs_info->subvol_sem);
 out_unlock:
@@ -2165,6 +2217,12 @@ out_unlock:
                 shrink_dcache_sb(root->fs_info->sb);
                 btrfs_invalidate_inodes(dest);
                 d_delete(dentry);
+
+                /* the last ref */
+                if (dest->cache_inode) {
+                        iput(dest->cache_inode);
+                        dest->cache_inode = NULL;
+                }
         }
 out_dput:
         dput(dentry);
@@ -2178,24 +2236,18 @@ out:
 
 static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
 {
-        struct inode *inode = fdentry(file)->d_inode;
+        struct inode *inode = file_inode(file);
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_ioctl_defrag_range_args *range;
         int ret;
 
-        if (btrfs_root_readonly(root))
-                return -EROFS;
-
-        if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
-                        1)) {
-                pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");
-                return -EINPROGRESS;
-        }
         ret = mnt_want_write_file(file);
-        if (ret) {
-                atomic_set(&root->fs_info->mutually_exclusive_operation_running,
-                           0);
+        if (ret)
                 return ret;
+
+        if (btrfs_root_readonly(root)) {
+                ret = -EROFS;
+                goto out;
         }
 
         switch (inode->i_mode & S_IFMT) {
@@ -2204,10 +2256,10 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
                         ret = -EPERM;
                         goto out;
                 }
-                ret = btrfs_defrag_root(root, 0);
+                ret = btrfs_defrag_root(root);
                 if (ret)
                         goto out;
-                ret = btrfs_defrag_root(root->fs_info->extent_root, 0);
+                ret = btrfs_defrag_root(root->fs_info->extent_root);
                 break;
         case S_IFREG:
                 if (!(file->f_mode & FMODE_WRITE)) {
@@ -2237,7 +2289,7 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
                         /* the rest are all set to zero by kzalloc */
                         range->len = (u64)-1;
                 }
-                ret = btrfs_defrag_file(fdentry(file)->d_inode, file,
+                ret = btrfs_defrag_file(file_inode(file), file,
                                         range, 0, 0);
                 if (ret > 0)
                         ret = 0;
@@ -2248,7 +2300,6 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
         }
 out:
         mnt_drop_write_file(file);
-        atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
         return ret;
 }
 
@@ -2263,7 +2314,7 @@ static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
         if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
                         1)) {
                 pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");
-                return -EINPROGRESS;
+                return -EINVAL;
         }
 
         mutex_lock(&root->fs_info->volume_mutex);
@@ -2285,7 +2336,7 @@ out:
 
 static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
 {
-        struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
+        struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
         struct btrfs_ioctl_vol_args *vol_args;
         int ret;
 
@@ -2300,7 +2351,7 @@ static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
                         1)) {
                 pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");
                 mnt_drop_write_file(file);
-                return -EINPROGRESS;
+                return -EINVAL;
         }
 
         mutex_lock(&root->fs_info->volume_mutex);
@@ -2316,8 +2367,8 @@ static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
         kfree(vol_args);
 out:
         mutex_unlock(&root->fs_info->volume_mutex);
-        mnt_drop_write_file(file);
         atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
+        mnt_drop_write_file(file);
         return ret;
 }
 
@@ -2408,7 +2459,7 @@ out:
 static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
                                        u64 off, u64 olen, u64 destoff)
 {
-        struct inode *inode = fdentry(file)->d_inode;
+        struct inode *inode = file_inode(file);
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct fd src_file;
         struct inode *src;
@@ -2454,7 +2505,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
         if (src_file.file->f_path.mnt != file->f_path.mnt)
                 goto out_fput;
 
-        src = src_file.file->f_dentry->d_inode;
+        src = file_inode(src_file.file);
 
         ret = -EINVAL;
         if (src == inode)
@@ -2816,7 +2867,7 @@ static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
  */
 static long btrfs_ioctl_trans_start(struct file *file)
 {
-        struct inode *inode = fdentry(file)->d_inode;
+        struct inode *inode = file_inode(file);
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_trans_handle *trans;
         int ret;
@@ -2856,7 +2907,7 @@ out:
 
 static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
 {
-        struct inode *inode = fdentry(file)->d_inode;
+        struct inode *inode = file_inode(file);
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_root *new_root;
         struct btrfs_dir_item *di;
@@ -3080,7 +3131,7 @@ out:
  */
 long btrfs_ioctl_trans_end(struct file *file)
 {
-        struct inode *inode = fdentry(file)->d_inode;
+        struct inode *inode = file_inode(file);
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_trans_handle *trans;
 
@@ -3104,7 +3155,7 @@ static noinline long btrfs_ioctl_start_sync(struct btrfs_root *root,
         u64 transid;
         int ret;
 
-        trans = btrfs_attach_transaction(root);
+        trans = btrfs_attach_transaction_barrier(root);
         if (IS_ERR(trans)) {
                 if (PTR_ERR(trans) != -ENOENT)
                         return PTR_ERR(trans);
@@ -3142,7 +3193,7 @@ static noinline long btrfs_ioctl_wait_sync(struct btrfs_root *root,
 
 static long btrfs_ioctl_scrub(struct file *file, void __user *arg)
 {
-        struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
+        struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
         struct btrfs_ioctl_scrub_args *sa;
         int ret;
 
@@ -3282,7 +3333,7 @@ static long btrfs_ioctl_ino_to_path(struct btrfs_root *root, void __user *arg)
         struct inode_fs_paths *ipath = NULL;
         struct btrfs_path *path;
 
-        if (!capable(CAP_SYS_ADMIN))
+        if (!capable(CAP_DAC_READ_SEARCH))
                 return -EPERM;
 
         path = btrfs_alloc_path();
@@ -3433,12 +3484,12 @@ void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
 
 static long btrfs_ioctl_balance(struct file *file, void __user *arg)
 {
-        struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
+        struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
         struct btrfs_fs_info *fs_info = root->fs_info;
         struct btrfs_ioctl_balance_args *bargs;
         struct btrfs_balance_control *bctl;
+        bool need_unlock; /* for mut. excl. ops lock */
         int ret;
-        int need_to_clear_lock = 0;
 
         if (!capable(CAP_SYS_ADMIN))
                 return -EPERM;
@@ -3447,14 +3498,61 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
         if (ret)
                 return ret;
 
-        mutex_lock(&fs_info->volume_mutex);
+again:
+        if (!atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1)) {
+                mutex_lock(&fs_info->volume_mutex);
+                mutex_lock(&fs_info->balance_mutex);
+                need_unlock = true;
+                goto locked;
+        }
+
+        /*
+         * mut. excl. ops lock is locked.  Three possibilites:
+         *   (1) some other op is running
+         *   (2) balance is running
+         *   (3) balance is paused -- special case (think resume)
+         */
         mutex_lock(&fs_info->balance_mutex);
+        if (fs_info->balance_ctl) {
+                /* this is either (2) or (3) */
+                if (!atomic_read(&fs_info->balance_running)) {
+                        mutex_unlock(&fs_info->balance_mutex);
+                        if (!mutex_trylock(&fs_info->volume_mutex))
+                                goto again;
+                        mutex_lock(&fs_info->balance_mutex);
+
+                        if (fs_info->balance_ctl &&
+                            !atomic_read(&fs_info->balance_running)) {
+                                /* this is (3) */
+                                need_unlock = false;
+                                goto locked;
+                        }
+
+                        mutex_unlock(&fs_info->balance_mutex);
+                        mutex_unlock(&fs_info->volume_mutex);
+                        goto again;
+                } else {
+                        /* this is (2) */
+                        mutex_unlock(&fs_info->balance_mutex);
+                        ret = -EINPROGRESS;
+                        goto out;
+                }
+        } else {
+                /* this is (1) */
+                mutex_unlock(&fs_info->balance_mutex);
+                pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");
+                ret = -EINVAL;
+                goto out;
+        }
+
+locked:
+        BUG_ON(!atomic_read(&fs_info->mutually_exclusive_operation_running));
 
         if (arg) {
                 bargs = memdup_user(arg, sizeof(*bargs));
                 if (IS_ERR(bargs)) {
                         ret = PTR_ERR(bargs);
-                        goto out;
+                        goto out_unlock;
                 }
 
                 if (bargs->flags & BTRFS_BALANCE_RESUME) {
@@ -3474,13 +3572,10 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
                 bargs = NULL;
         }
 
-        if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
-                        1)) {
-                pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");
+        if (fs_info->balance_ctl) {
                 ret = -EINPROGRESS;
                 goto out_bargs;
         }
-        need_to_clear_lock = 1;
 
         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
         if (!bctl) {
@@ -3501,11 +3596,17 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
         }
 
 do_balance:
-        ret = btrfs_balance(bctl, bargs);
         /*
-         * bctl is freed in __cancel_balance or in free_fs_info if
-         * restriper was paused all the way until unmount
+         * Ownership of bctl and mutually_exclusive_operation_running
+         * goes to to btrfs_balance.  bctl is freed in __cancel_balance,
+         * or, if restriper was paused all the way until unmount, in
+         * free_fs_info.  mutually_exclusive_operation_running is
+         * cleared in __cancel_balance.
          */
+        need_unlock = false;
+
+        ret = btrfs_balance(bctl, bargs);
+
         if (arg) {
                 if (copy_to_user(arg, bargs, sizeof(*bargs)))
                         ret = -EFAULT;
@@ -3513,12 +3614,12 @@ do_balance:
 
 out_bargs:
         kfree(bargs);
-out:
-        if (need_to_clear_lock)
-                atomic_set(&root->fs_info->mutually_exclusive_operation_running,
-                           0);
+out_unlock:
         mutex_unlock(&fs_info->balance_mutex);
         mutex_unlock(&fs_info->volume_mutex);
+        if (need_unlock)
+                atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
+out:
         mnt_drop_write_file(file);
         return ret;
 }
@@ -3573,7 +3674,7 @@ out:
 
 static long btrfs_ioctl_quota_ctl(struct file *file, void __user *arg)
 {
-        struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
+        struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
         struct btrfs_ioctl_quota_ctl_args *sa;
         struct btrfs_trans_handle *trans = NULL;
         int ret;
@@ -3632,7 +3733,7 @@ drop_write:
 
 static long btrfs_ioctl_qgroup_assign(struct file *file, void __user *arg)
 {
-        struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
+        struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
         struct btrfs_ioctl_qgroup_assign_args *sa;
         struct btrfs_trans_handle *trans;
         int ret;
@@ -3679,7 +3780,7 @@ drop_write:
 
 static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg)
 {
-        struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
+        struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
         struct btrfs_ioctl_qgroup_create_args *sa;
         struct btrfs_trans_handle *trans;
         int ret;
@@ -3698,6 +3799,11 @@ static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg)
                 goto drop_write;
         }
 
+        if (!sa->qgroupid) {
+                ret = -EINVAL;
+                goto out;
+        }
+
         trans = btrfs_join_transaction(root);
         if (IS_ERR(trans)) {
                 ret = PTR_ERR(trans);
@@ -3725,7 +3831,7 @@ drop_write:
 
 static long btrfs_ioctl_qgroup_limit(struct file *file, void __user *arg)
 {
-        struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
+        struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
         struct btrfs_ioctl_qgroup_limit_args *sa;
         struct btrfs_trans_handle *trans;
         int ret;
@@ -3775,7 +3881,7 @@ static long btrfs_ioctl_set_received_subvol(struct file *file,
                                             void __user *arg)
 {
         struct btrfs_ioctl_received_subvol_args *sa = NULL;
-        struct inode *inode = fdentry(file)->d_inode;
+        struct inode *inode = file_inode(file);
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_root_item *root_item = &root->root_item;
         struct btrfs_trans_handle *trans;
@@ -3852,10 +3958,69 @@ out:
         return ret;
 }
 
+static int btrfs_ioctl_get_fslabel(struct file *file, void __user *arg)
+{
+        struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
+        const char *label = root->fs_info->super_copy->label;
+        size_t len = strnlen(label, BTRFS_LABEL_SIZE);
+        int ret;
+
+        if (len == BTRFS_LABEL_SIZE) {
+                pr_warn("btrfs: label is too long, return the first %zu bytes\n",
+                        --len);
+        }
+
+        mutex_lock(&root->fs_info->volume_mutex);
+        ret = copy_to_user(arg, label, len);
+        mutex_unlock(&root->fs_info->volume_mutex);
+
+        return ret ? -EFAULT : 0;
+}
+
+static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg)
+{
+        struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
+        struct btrfs_super_block *super_block = root->fs_info->super_copy;
+        struct btrfs_trans_handle *trans;
+        char label[BTRFS_LABEL_SIZE];
+        int ret;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        if (copy_from_user(label, arg, sizeof(label)))
+                return -EFAULT;
+
+        if (strnlen(label, BTRFS_LABEL_SIZE) == BTRFS_LABEL_SIZE) {
+                pr_err("btrfs: unable to set label with more than %d bytes\n",
+                       BTRFS_LABEL_SIZE - 1);
+                return -EINVAL;
+        }
+
+        ret = mnt_want_write_file(file);
+        if (ret)
+                return ret;
+
+        mutex_lock(&root->fs_info->volume_mutex);
+        trans = btrfs_start_transaction(root, 0);
+        if (IS_ERR(trans)) {
+                ret = PTR_ERR(trans);
+                goto out_unlock;
+        }
+
+        strcpy(super_block->label, label);
+        ret = btrfs_end_transaction(trans, root);
+
+out_unlock:
+        mutex_unlock(&root->fs_info->volume_mutex);
+        mnt_drop_write_file(file);
+        return ret;
+}
+
 long btrfs_ioctl(struct file *file, unsigned int
                 cmd, unsigned long arg)
 {
-        struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
+        struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
         void __user *argp = (void __user *)arg;
 
         switch (cmd) {
@@ -3952,6 +4117,10 @@ long btrfs_ioctl(struct file *file, unsigned int
                 return btrfs_ioctl_qgroup_limit(file, argp);
         case BTRFS_IOC_DEV_REPLACE:
                 return btrfs_ioctl_dev_replace(root, argp);
+        case BTRFS_IOC_GET_FSLABEL:
+                return btrfs_ioctl_get_fslabel(file, argp);
+        case BTRFS_IOC_SET_FSLABEL:
+                return btrfs_ioctl_set_fslabel(file, argp);
         }
 
         return -ENOTTY;