1 files changed, 304 insertions, 100 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 21da5762b0b1..a6d8efa46bfe 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -56,6 +56,8 @@
 #include "rcu-string.h"
 #include "send.h"
 #include "dev-replace.h"
+#include "props.h"
+#include "sysfs.h"
 
 static int btrfs_clone(struct inode *src, struct inode *inode,
                        u64 off, u64 olen, u64 olen_aligned, u64 destoff);
@@ -190,6 +192,9 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
         unsigned int i_oldflags;
         umode_t mode;
 
+        if (!inode_owner_or_capable(inode))
+                return -EPERM;
+
         if (btrfs_root_readonly(root))
                 return -EROFS;
 
@@ -200,9 +205,6 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
         if (ret)
                 return ret;
 
-        if (!inode_owner_or_capable(inode))
-                return -EACCES;
-
         ret = mnt_want_write_file(file);
         if (ret)
                 return ret;
@@ -280,9 +282,25 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
         if (flags & FS_NOCOMP_FL) {
                 ip->flags &= ~BTRFS_INODE_COMPRESS;
                 ip->flags |= BTRFS_INODE_NOCOMPRESS;
+
+                ret = btrfs_set_prop(inode, "btrfs.compression", NULL, 0, 0);
+                if (ret && ret != -ENODATA)
+                        goto out_drop;
         } else if (flags & FS_COMPR_FL) {
+                const char *comp;
+
                 ip->flags |= BTRFS_INODE_COMPRESS;
                 ip->flags &= ~BTRFS_INODE_NOCOMPRESS;
+
+                if (root->fs_info->compress_type == BTRFS_COMPRESS_LZO)
+                        comp = "lzo";
+                else
+                        comp = "zlib";
+                ret = btrfs_set_prop(inode, "btrfs.compression",
+                                     comp, strlen(comp), 0);
+                if (ret)
+                        goto out_drop;
+
         } else {
                 ip->flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
         }
@@ -392,6 +410,7 @@ static noinline int create_subvol(struct inode *dir,
         struct btrfs_root *new_root;
         struct btrfs_block_rsv block_rsv;
         struct timespec cur_time = CURRENT_TIME;
+        struct inode *inode;
         int ret;
         int err;
         u64 objectid;
@@ -417,7 +436,9 @@ static noinline int create_subvol(struct inode *dir,
         trans = btrfs_start_transaction(root, 0);
         if (IS_ERR(trans)) {
                 ret = PTR_ERR(trans);
-                goto out;
+                btrfs_subvolume_release_metadata(root, &block_rsv,
+                                                 qgroup_reserved);
+                return ret;
         }
         trans->block_rsv = &block_rsv;
         trans->bytes_reserved = block_rsv.size;
@@ -500,7 +521,7 @@ static noinline int create_subvol(struct inode *dir,
 
         btrfs_record_root_in_trans(trans, new_root);
 
-        ret = btrfs_create_subvol_root(trans, new_root, new_dirid);
+        ret = btrfs_create_subvol_root(trans, new_root, root, new_dirid);
         if (ret) {
                 /* We potentially lose an unused inode item here */
                 btrfs_abort_transaction(trans, root, ret);
@@ -542,6 +563,8 @@ static noinline int create_subvol(struct inode *dir,
 fail:
         trans->block_rsv = NULL;
         trans->bytes_reserved = 0;
+        btrfs_subvolume_release_metadata(root, &block_rsv, qgroup_reserved);
+
         if (async_transid) {
                 *async_transid = trans->transid;
                 err = btrfs_commit_transaction_async(trans, root, 1);
@@ -553,10 +576,12 @@ fail:
         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);
+        if (!ret) {
+                inode = btrfs_lookup_dentry(dir, dentry);
+                if (IS_ERR(inode))
+                        return PTR_ERR(inode);
+                d_instantiate(dentry, inode);
+        }
         return ret;
 }
 
@@ -642,7 +667,7 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir,
                 ret = PTR_ERR(inode);
                 goto fail;
         }
-        BUG_ON(!inode);
+
         d_instantiate(dentry, inode);
         ret = 0;
 fail:
@@ -1011,7 +1036,7 @@ out:
 static int cluster_pages_for_defrag(struct inode *inode,
                                     struct page **pages,
                                     unsigned long start_index,
-                                    int num_pages)
+                                    unsigned long num_pages)
 {
         unsigned long file_end;
         u64 isize = i_size_read(inode);
@@ -1169,8 +1194,8 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
         int defrag_count = 0;
         int compress_type = BTRFS_COMPRESS_ZLIB;
         int extent_thresh = range->extent_thresh;
-        int max_cluster = (256 * 1024) >> PAGE_CACHE_SHIFT;
-        int cluster = max_cluster;
+        unsigned long max_cluster = (256 * 1024) >> PAGE_CACHE_SHIFT;
+        unsigned long cluster = max_cluster;
         u64 new_align = ~((u64)128 * 1024 - 1);
         struct page **pages = NULL;
 
@@ -1254,7 +1279,7 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
                         break;
 
                 if (btrfs_defrag_cancelled(root->fs_info)) {
-                        printk(KERN_DEBUG "btrfs: defrag_file cancelled\n");
+                        printk(KERN_DEBUG "BTRFS: defrag_file cancelled\n");
                         ret = -EAGAIN;
                         break;
                 }
@@ -1416,20 +1441,20 @@ static noinline int btrfs_ioctl_resize(struct file *file,
                         ret = -EINVAL;
                         goto out_free;
                 }
-                printk(KERN_INFO "btrfs: resizing devid %llu\n", devid);
+                btrfs_info(root->fs_info, "resizing devid %llu", devid);
         }
 
         device = btrfs_find_device(root->fs_info, devid, NULL, NULL);
         if (!device) {
-                printk(KERN_INFO "btrfs: resizer unable to find device %llu\n",
+                btrfs_info(root->fs_info, "resizer unable to find device %llu",
                        devid);
                 ret = -ENODEV;
                 goto out_free;
         }
 
         if (!device->writeable) {
-                printk(KERN_INFO "btrfs: resizer unable to apply on "
-                       "readonly device %llu\n",
+                btrfs_info(root->fs_info,
+                           "resizer unable to apply on readonly device %llu",
                        devid);
                 ret = -EPERM;
                 goto out_free;
@@ -1466,6 +1491,10 @@ static noinline int btrfs_ioctl_resize(struct file *file,
                 }
                 new_size = old_size - new_size;
         } else if (mod > 0) {
+                if (new_size > ULLONG_MAX - old_size) {
+                        ret = -EINVAL;
+                        goto out_free;
+                }
                 new_size = old_size + new_size;
         }
 
@@ -1481,7 +1510,7 @@ static noinline int btrfs_ioctl_resize(struct file *file,
         do_div(new_size, root->sectorsize);
         new_size *= root->sectorsize;
 
-        printk_in_rcu(KERN_INFO "btrfs: new size for %s is %llu\n",
+        printk_in_rcu(KERN_INFO "BTRFS: new size for %s is %llu\n",
                       rcu_str_deref(device->name), new_size);
 
         if (new_size > old_size) {
@@ -1542,9 +1571,15 @@ static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
 
                 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");
+                        btrfs_info(BTRFS_I(src_inode)->root->fs_info,
+                                   "Snapshot src from another FS");
                         ret = -EINVAL;
+                } else if (!inode_owner_or_capable(src_inode)) {
+                        /*
+                         * Subvolume creation is not restricted, but snapshots
+                         * are limited to own subvolumes only
+                         */
+                        ret = -EPERM;
                 } else {
                         ret = btrfs_mksubvol(&file->f_path, name, namelen,
                                              BTRFS_I(src_inode)->root,
@@ -1662,6 +1697,9 @@ static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
         u64 flags;
         int ret = 0;
 
+        if (!inode_owner_or_capable(inode))
+                return -EPERM;
+
         ret = mnt_want_write_file(file);
         if (ret)
                 goto out;
@@ -1686,11 +1724,6 @@ static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
                 goto out_drop_write;
         }
 
-        if (!inode_owner_or_capable(inode)) {
-                ret = -EACCES;
-                goto out_drop_write;
-        }
-
         down_write(&root->fs_info->subvol_sem);
 
         /* nothing to do */
@@ -1698,12 +1731,28 @@ static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
                 goto out_drop_sem;
 
         root_flags = btrfs_root_flags(&root->root_item);
-        if (flags & BTRFS_SUBVOL_RDONLY)
+        if (flags & BTRFS_SUBVOL_RDONLY) {
                 btrfs_set_root_flags(&root->root_item,
                                      root_flags | BTRFS_ROOT_SUBVOL_RDONLY);
-        else
-                btrfs_set_root_flags(&root->root_item,
+        } else {
+                /*
+                 * Block RO -> RW transition if this subvolume is involved in
+                 * send
+                 */
+                spin_lock(&root->root_item_lock);
+                if (root->send_in_progress == 0) {
+                        btrfs_set_root_flags(&root->root_item,
                                      root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY);
+                        spin_unlock(&root->root_item_lock);
+                } else {
+                        spin_unlock(&root->root_item_lock);
+                        btrfs_warn(root->fs_info,
+                        "Attempt to set subvolume %llu read-write during send",
+                                        root->root_key.objectid);
+                        ret = -EPERM;
+                        goto out_drop_sem;
+                }
+        }
 
         trans = btrfs_start_transaction(root, 1);
         if (IS_ERR(trans)) {
@@ -1910,7 +1959,7 @@ static noinline int search_ioctl(struct inode *inode,
                 key.offset = (u64)-1;
                 root = btrfs_read_fs_root_no_name(info, &key);
                 if (IS_ERR(root)) {
-                        printk(KERN_ERR "could not find root %llu\n",
+                        printk(KERN_ERR "BTRFS: could not find root %llu\n",
                                sk->tree_id);
                         btrfs_free_path(path);
                         return -ENOENT;
@@ -2000,7 +2049,7 @@ static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
         key.offset = (u64)-1;
         root = btrfs_read_fs_root_no_name(info, &key);
         if (IS_ERR(root)) {
-                printk(KERN_ERR "could not find root %llu\n", tree_id);
+                printk(KERN_ERR "BTRFS: could not find root %llu\n", tree_id);
                 ret = -ENOENT;
                 goto out;
         }
@@ -2686,14 +2735,11 @@ out_unlock:
 #define BTRFS_MAX_DEDUPE_LEN    (16 * 1024 * 1024)
 
 static long btrfs_ioctl_file_extent_same(struct file *file,
-                                         void __user *argp)
+                        struct btrfs_ioctl_same_args __user *argp)
 {
-        struct btrfs_ioctl_same_args tmp;
         struct btrfs_ioctl_same_args *same;
         struct btrfs_ioctl_same_extent_info *info;
-        struct inode *src = file->f_dentry->d_inode;
-        struct file *dst_file = NULL;
-        struct inode *dst;
+        struct inode *src = file_inode(file);
         u64 off;
         u64 len;
         int i;
@@ -2701,6 +2747,7 @@ static long btrfs_ioctl_file_extent_same(struct file *file,
         unsigned long size;
         u64 bs = BTRFS_I(src)->root->fs_info->sb->s_blocksize;
         bool is_admin = capable(CAP_SYS_ADMIN);
+        u16 count;
 
         if (!(file->f_mode & FMODE_READ))
                 return -EINVAL;
@@ -2709,17 +2756,14 @@ static long btrfs_ioctl_file_extent_same(struct file *file,
         if (ret)
                 return ret;
 
-        if (copy_from_user(&tmp,
-                           (struct btrfs_ioctl_same_args __user *)argp,
-                           sizeof(tmp))) {
+        if (get_user(count, &argp->dest_count)) {
                 ret = -EFAULT;
                 goto out;
         }
 
-        size = sizeof(tmp) +
-                tmp.dest_count * sizeof(struct btrfs_ioctl_same_extent_info);
+        size = offsetof(struct btrfs_ioctl_same_args __user, info[count]);
 
-        same = memdup_user((struct btrfs_ioctl_same_args __user *)argp, size);
+        same = memdup_user(argp, size);
 
         if (IS_ERR(same)) {
                 ret = PTR_ERR(same);
@@ -2756,52 +2800,35 @@ static long btrfs_ioctl_file_extent_same(struct file *file,
                 goto out;
 
         /* pre-format output fields to sane values */
-        for (i = 0; i < same->dest_count; i++) {
+        for (i = 0; i < count; i++) {
                 same->info[i].bytes_deduped = 0ULL;
                 same->info[i].status = 0;
         }
 
-        ret = 0;
-        for (i = 0; i < same->dest_count; i++) {
-                info = &same->info[i];
-
-                dst_file = fget(info->fd);
-                if (!dst_file) {
+        for (i = 0, info = same->info; i < count; i++, info++) {
+                struct inode *dst;
+                struct fd dst_file = fdget(info->fd);
+                if (!dst_file.file) {
                         info->status = -EBADF;
-                        goto next;
+                        continue;
                 }
+                dst = file_inode(dst_file.file);
 
-                if (!(is_admin || (dst_file->f_mode & FMODE_WRITE))) {
+                if (!(is_admin || (dst_file.file->f_mode & FMODE_WRITE))) {
                         info->status = -EINVAL;
-                        goto next;
-                }
-
-                info->status = -EXDEV;
-                if (file->f_path.mnt != dst_file->f_path.mnt)
-                        goto next;
-
-                dst = dst_file->f_dentry->d_inode;
-                if (src->i_sb != dst->i_sb)
-                        goto next;
-
-                if (S_ISDIR(dst->i_mode)) {
+                } else if (file->f_path.mnt != dst_file.file->f_path.mnt) {
+                        info->status = -EXDEV;
+                } else if (S_ISDIR(dst->i_mode)) {
                         info->status = -EISDIR;
-                        goto next;
-                }
-
-                if (!S_ISREG(dst->i_mode)) {
+                } else if (!S_ISREG(dst->i_mode)) {
                         info->status = -EACCES;
-                        goto next;
+                } else {
+                        info->status = btrfs_extent_same(src, off, len, dst,
+                                                        info->logical_offset);
+                        if (info->status == 0)
+                                info->bytes_deduped += len;
                 }
-
-                info->status = btrfs_extent_same(src, off, len, dst,
-                                                info->logical_offset);
-                if (info->status == 0)
-                        info->bytes_deduped += len;
-
-next:
-                if (dst_file)
-                        fput(dst_file);
+                fdput(dst_file);
         }
 
         ret = copy_to_user(argp, same, size);
@@ -2860,12 +2887,14 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
                  * note the key will change type as we walk through the
                  * tree.
                  */
+                path->leave_spinning = 1;
                 ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
                                 0, 0);
                 if (ret < 0)
                         goto out;
 
                 nritems = btrfs_header_nritems(path->nodes[0]);
+process_slot:
                 if (path->slots[0] >= nritems) {
                         ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
                         if (ret < 0)
@@ -2892,11 +2921,6 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
                         u8 comp;
                         u64 endoff;
 
-                        size = btrfs_item_size_nr(leaf, slot);
-                        read_extent_buffer(leaf, buf,
-                                           btrfs_item_ptr_offset(leaf, slot),
-                                           size);
-
                         extent = btrfs_item_ptr(leaf, slot,
                                                 struct btrfs_file_extent_item);
                         comp = btrfs_file_extent_compression(leaf, extent);
@@ -2915,11 +2939,20 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
                                 datal = btrfs_file_extent_ram_bytes(leaf,
                                                                     extent);
                         }
-                        btrfs_release_path(path);
 
                         if (key.offset + datal <= off ||
-                            key.offset >= off + len - 1)
-                                goto next;
+                            key.offset >= off + len - 1) {
+                                path->slots[0]++;
+                                goto process_slot;
+                        }
+
+                        size = btrfs_item_size_nr(leaf, slot);
+                        read_extent_buffer(leaf, buf,
+                                           btrfs_item_ptr_offset(leaf, slot),
+                                           size);
+
+                        btrfs_release_path(path);
+                        path->leave_spinning = 0;
 
                         memcpy(&new_key, &key, sizeof(new_key));
                         new_key.objectid = btrfs_ino(inode);
@@ -3090,7 +3123,6 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
                         }
                         ret = btrfs_end_transaction(trans, root);
                 }
-next:
                 btrfs_release_path(path);
                 key.offset++;
         }
@@ -3218,9 +3250,17 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
 
         unlock_extent(&BTRFS_I(src)->io_tree, off, off + len - 1);
 out_unlock:
-        mutex_unlock(&src->i_mutex);
-        if (!same_inode)
-                mutex_unlock(&inode->i_mutex);
+        if (!same_inode) {
+                if (inode < src) {
+                        mutex_unlock(&src->i_mutex);
+                        mutex_unlock(&inode->i_mutex);
+                } else {
+                        mutex_unlock(&inode->i_mutex);
+                        mutex_unlock(&src->i_mutex);
+                }
+        } else {
+                mutex_unlock(&src->i_mutex);
+        }
 out_fput:
         fdput(src_file);
 out_drop_write:
@@ -3343,8 +3383,8 @@ static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
         if (IS_ERR_OR_NULL(di)) {
                 btrfs_free_path(path);
                 btrfs_end_transaction(trans, root);
-                printk(KERN_ERR "Umm, you don't have the default dir item, "
-                       "this isn't going to work\n");
+                btrfs_err(new_root->fs_info, "Umm, you don't have the default dir"
+                           "item, this isn't going to work");
                 ret = -ENOENT;
                 goto out;
         }
@@ -4325,6 +4365,9 @@ static long btrfs_ioctl_set_received_subvol(struct file *file,
         int ret = 0;
         int received_uuid_changed;
 
+        if (!inode_owner_or_capable(inode))
+                return -EPERM;
+
         ret = mnt_want_write_file(file);
         if (ret < 0)
                 return ret;
@@ -4341,11 +4384,6 @@ static long btrfs_ioctl_set_received_subvol(struct file *file,
                 goto out;
         }
 
-        if (!inode_owner_or_capable(inode)) {
-                ret = -EACCES;
-                goto out;
-        }
-
         sa = memdup_user(arg, sizeof(*sa));
         if (IS_ERR(sa)) {
                 ret = PTR_ERR(sa);
@@ -4431,8 +4469,8 @@ static int btrfs_ioctl_get_fslabel(struct file *file, void __user *arg)
         len = strnlen(label, BTRFS_LABEL_SIZE);
 
         if (len == BTRFS_LABEL_SIZE) {
-                pr_warn("btrfs: label is too long, return the first %zu bytes\n",
-                        --len);
+                btrfs_warn(root->fs_info,
+                        "label is too long, return the first %zu bytes", --len);
         }
 
         ret = copy_to_user(arg, label, len);
@@ -4455,7 +4493,7 @@ static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg)
                 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_err(root->fs_info, "unable to set label with more than %d bytes",
                        BTRFS_LABEL_SIZE - 1);
                 return -EINVAL;
         }
@@ -4473,13 +4511,173 @@ static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg)
         spin_lock(&root->fs_info->super_lock);
         strcpy(super_block->label, label);
         spin_unlock(&root->fs_info->super_lock);
-        ret = btrfs_end_transaction(trans, root);
+        ret = btrfs_commit_transaction(trans, root);
 
 out_unlock:
         mnt_drop_write_file(file);
         return ret;
 }
 
+#define INIT_FEATURE_FLAGS(suffix) \
+        { .compat_flags = BTRFS_FEATURE_COMPAT_##suffix, \
+          .compat_ro_flags = BTRFS_FEATURE_COMPAT_RO_##suffix, \
+          .incompat_flags = BTRFS_FEATURE_INCOMPAT_##suffix }
+
+static int btrfs_ioctl_get_supported_features(struct file *file,
+                                              void __user *arg)
+{
+        static struct btrfs_ioctl_feature_flags features[3] = {
+                INIT_FEATURE_FLAGS(SUPP),
+                INIT_FEATURE_FLAGS(SAFE_SET),
+                INIT_FEATURE_FLAGS(SAFE_CLEAR)
+        };
+
+        if (copy_to_user(arg, &features, sizeof(features)))
+                return -EFAULT;
+
+        return 0;
+}
+
+static int btrfs_ioctl_get_features(struct file *file, void __user *arg)
+{
+        struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
+        struct btrfs_super_block *super_block = root->fs_info->super_copy;
+        struct btrfs_ioctl_feature_flags features;
+
+        features.compat_flags = btrfs_super_compat_flags(super_block);
+        features.compat_ro_flags = btrfs_super_compat_ro_flags(super_block);
+        features.incompat_flags = btrfs_super_incompat_flags(super_block);
+
+        if (copy_to_user(arg, &features, sizeof(features)))
+                return -EFAULT;
+
+        return 0;
+}
+
+static int check_feature_bits(struct btrfs_root *root,
+                              enum btrfs_feature_set set,
+                              u64 change_mask, u64 flags, u64 supported_flags,
+                              u64 safe_set, u64 safe_clear)
+{
+        const char *type = btrfs_feature_set_names[set];
+        char *names;
+        u64 disallowed, unsupported;
+        u64 set_mask = flags & change_mask;
+        u64 clear_mask = ~flags & change_mask;
+
+        unsupported = set_mask & ~supported_flags;
+        if (unsupported) {
+                names = btrfs_printable_features(set, unsupported);
+                if (names) {
+                        btrfs_warn(root->fs_info,
+                           "this kernel does not support the %s feature bit%s",
+                           names, strchr(names, ',') ? "s" : "");
+                        kfree(names);
+                } else
+                        btrfs_warn(root->fs_info,
+                           "this kernel does not support %s bits 0x%llx",
+                           type, unsupported);
+                return -EOPNOTSUPP;
+        }
+
+        disallowed = set_mask & ~safe_set;
+        if (disallowed) {
+                names = btrfs_printable_features(set, disallowed);
+                if (names) {
+                        btrfs_warn(root->fs_info,
+                           "can't set the %s feature bit%s while mounted",
+                           names, strchr(names, ',') ? "s" : "");
+                        kfree(names);
+                } else
+                        btrfs_warn(root->fs_info,
+                           "can't set %s bits 0x%llx while mounted",
+                           type, disallowed);
+                return -EPERM;
+        }
+
+        disallowed = clear_mask & ~safe_clear;
+        if (disallowed) {
+                names = btrfs_printable_features(set, disallowed);
+                if (names) {
+                        btrfs_warn(root->fs_info,
+                           "can't clear the %s feature bit%s while mounted",
+                           names, strchr(names, ',') ? "s" : "");
+                        kfree(names);
+                } else
+                        btrfs_warn(root->fs_info,
+                           "can't clear %s bits 0x%llx while mounted",
+                           type, disallowed);
+                return -EPERM;
+        }
+
+        return 0;
+}
+
+#define check_feature(root, change_mask, flags, mask_base)      \
+check_feature_bits(root, FEAT_##mask_base, change_mask, flags,  \
+                   BTRFS_FEATURE_ ## mask_base ## _SUPP,        \
+                   BTRFS_FEATURE_ ## mask_base ## _SAFE_SET,    \
+                   BTRFS_FEATURE_ ## mask_base ## _SAFE_CLEAR)
+
+static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
+{
+        struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
+        struct btrfs_super_block *super_block = root->fs_info->super_copy;
+        struct btrfs_ioctl_feature_flags flags[2];
+        struct btrfs_trans_handle *trans;
+        u64 newflags;
+        int ret;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        if (copy_from_user(flags, arg, sizeof(flags)))
+                return -EFAULT;
+
+        /* Nothing to do */
+        if (!flags[0].compat_flags && !flags[0].compat_ro_flags &&
+            !flags[0].incompat_flags)
+                return 0;
+
+        ret = check_feature(root, flags[0].compat_flags,
+                            flags[1].compat_flags, COMPAT);
+        if (ret)
+                return ret;
+
+        ret = check_feature(root, flags[0].compat_ro_flags,
+                            flags[1].compat_ro_flags, COMPAT_RO);
+        if (ret)
+                return ret;
+
+        ret = check_feature(root, flags[0].incompat_flags,
+                            flags[1].incompat_flags, INCOMPAT);
+        if (ret)
+                return ret;
+
+        trans = btrfs_start_transaction(root, 0);
+        if (IS_ERR(trans))
+                return PTR_ERR(trans);
+
+        spin_lock(&root->fs_info->super_lock);
+        newflags = btrfs_super_compat_flags(super_block);
+        newflags |= flags[0].compat_flags & flags[1].compat_flags;
+        newflags &= ~(flags[0].compat_flags & ~flags[1].compat_flags);
+        btrfs_set_super_compat_flags(super_block, newflags);
+
+        newflags = btrfs_super_compat_ro_flags(super_block);
+        newflags |= flags[0].compat_ro_flags & flags[1].compat_ro_flags;
+        newflags &= ~(flags[0].compat_ro_flags & ~flags[1].compat_ro_flags);
+        btrfs_set_super_compat_ro_flags(super_block, newflags);
+
+        newflags = btrfs_super_incompat_flags(super_block);
+        newflags |= flags[0].incompat_flags & flags[1].incompat_flags;
+        newflags &= ~(flags[0].incompat_flags & ~flags[1].incompat_flags);
+        btrfs_set_super_incompat_flags(super_block, newflags);
+        spin_unlock(&root->fs_info->super_lock);
+
+        return btrfs_commit_transaction(trans, root);
+}
+
 long btrfs_ioctl(struct file *file, unsigned int
                 cmd, unsigned long arg)
 {
@@ -4598,6 +4796,12 @@ long btrfs_ioctl(struct file *file, unsigned int
                 return btrfs_ioctl_set_fslabel(file, argp);
         case BTRFS_IOC_FILE_EXTENT_SAME:
                 return btrfs_ioctl_file_extent_same(file, argp);
+        case BTRFS_IOC_GET_SUPPORTED_FEATURES:
+                return btrfs_ioctl_get_supported_features(file, argp);
+        case BTRFS_IOC_GET_FEATURES:
+                return btrfs_ioctl_get_features(file, argp);
+        case BTRFS_IOC_SET_FEATURES:
+                return btrfs_ioctl_set_features(file, argp);
         }
 
         return -ENOTTY;