Btrfs: add qgroup inheritance

When creating a subvolume or snapshot, it is necessary
to initialize the qgroup account with a copy of some
other (tracking) qgroup. This patch adds parameters
to the ioctls to pass the information from which qgroup
to inherit.

Signed-off-by: Arne Jansen <sensille@gmx.net>

4 files changed, 61 insertions, 18 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 55a7283a9e18..1dffd0adf975 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -336,7 +336,8 @@ static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
 static noinline int create_subvol(struct btrfs_root *root,
                                   struct dentry *dentry,
                                   char *name, int namelen,
-                                  u64 *async_transid)
+                                  u64 *async_transid,
+                                  struct btrfs_qgroup_inherit **inherit)
 {
         struct btrfs_trans_handle *trans;
         struct btrfs_key key;
@@ -368,6 +369,11 @@ static noinline int create_subvol(struct btrfs_root *root,
         if (IS_ERR(trans))
                 return PTR_ERR(trans);
 
+        ret = btrfs_qgroup_inherit(trans, root->fs_info, 0, objectid,
+                                   inherit ? *inherit : NULL);
+        if (ret)
+                goto fail;
+
         leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
                                       0, objectid, NULL, 0, 0, 0);
         if (IS_ERR(leaf)) {
@@ -484,7 +490,7 @@ fail:
 
 static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
                            char *name, int namelen, u64 *async_transid,
-                           bool readonly)
+                           bool readonly, struct btrfs_qgroup_inherit **inherit)
 {
         struct inode *inode;
         struct btrfs_pending_snapshot *pending_snapshot;
@@ -502,6 +508,10 @@ static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
         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 */
+        }
 
         trans = btrfs_start_transaction(root->fs_info->extent_root, 5);
         if (IS_ERR(trans)) {
@@ -635,7 +645,8 @@ static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
 static noinline int btrfs_mksubvol(struct path *parent,
                                    char *name, int namelen,
                                    struct btrfs_root *snap_src,
-                                   u64 *async_transid, bool readonly)
+                                   u64 *async_transid, bool readonly,
+                                   struct btrfs_qgroup_inherit **inherit)
 {
         struct inode *dir  = parent->dentry->d_inode;
         struct dentry *dentry;
@@ -666,11 +677,11 @@ static noinline int btrfs_mksubvol(struct path *parent,
                 goto out_up_read;
 
         if (snap_src) {
-                error = create_snapshot(snap_src, dentry,
-                                        name, namelen, async_transid, readonly);
+                error = create_snapshot(snap_src, dentry, name, namelen,
+                                        async_transid, readonly, inherit);
         } else {
                 error = create_subvol(BTRFS_I(dir)->root, dentry,
-                                      name, namelen, async_transid);
+                                      name, namelen, async_transid, inherit);
         }
         if (!error)
                 fsnotify_mkdir(dir, dentry);
@@ -1379,11 +1390,9 @@ out:
 }
 
 static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
-                                                    char *name,
-                                                    unsigned long fd,
-                                                    int subvol,
-                                                    u64 *transid,
-                                                    bool readonly)
+                                char *name, unsigned long fd, int subvol,
+                                u64 *transid, bool readonly,
+                                struct btrfs_qgroup_inherit **inherit)
 {
         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
         struct file *src_file;
@@ -1407,7 +1416,7 @@ static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
 
         if (subvol) {
                 ret = btrfs_mksubvol(&file->f_path, name, namelen,
-                                     NULL, transid, readonly);
+                                     NULL, transid, readonly, inherit);
         } else {
                 struct inode *src_inode;
                 src_file = fget(fd);
@@ -1426,7 +1435,7 @@ static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
                 }
                 ret = btrfs_mksubvol(&file->f_path, name, namelen,
                                      BTRFS_I(src_inode)->root,
-                                     transid, readonly);
+                                     transid, readonly, inherit);
                 fput(src_file);
         }
 out:
@@ -1446,7 +1455,7 @@ static noinline int btrfs_ioctl_snap_create(struct file *file,
 
         ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
                                               vol_args->fd, subvol,
-                                              NULL, false);
+                                              NULL, false, NULL);
 
         kfree(vol_args);
         return ret;
@@ -1460,6 +1469,7 @@ static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
         u64 transid = 0;
         u64 *ptr = NULL;
         bool readonly = false;
+        struct btrfs_qgroup_inherit *inherit = NULL;
 
         vol_args = memdup_user(arg, sizeof(*vol_args));
         if (IS_ERR(vol_args))
@@ -1467,7 +1477,8 @@ static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
         vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
 
         if (vol_args->flags &
-            ~(BTRFS_SUBVOL_CREATE_ASYNC | BTRFS_SUBVOL_RDONLY)) {
+            ~(BTRFS_SUBVOL_CREATE_ASYNC | BTRFS_SUBVOL_RDONLY |
+              BTRFS_SUBVOL_QGROUP_INHERIT)) {
                 ret = -EOPNOTSUPP;
                 goto out;
         }
@@ -1476,10 +1487,21 @@ static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
                 ptr = &transid;
         if (vol_args->flags & BTRFS_SUBVOL_RDONLY)
                 readonly = true;
+        if (vol_args->flags & BTRFS_SUBVOL_QGROUP_INHERIT) {
+                if (vol_args->size > PAGE_CACHE_SIZE) {
+                        ret = -EINVAL;
+                        goto out;
+                }
+                inherit = memdup_user(vol_args->qgroup_inherit, vol_args->size);
+                if (IS_ERR(inherit)) {
+                        ret = PTR_ERR(inherit);
+                        goto out;
+                }
+        }
 
         ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
-                                              vol_args->fd, subvol,
-                                              ptr, readonly);
+                                              vol_args->fd, subvol, ptr,
+                                              readonly, &inherit);
 
         if (ret == 0 && ptr &&
             copy_to_user(arg +
@@ -1488,6 +1510,7 @@ static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
                 ret = -EFAULT;
 out:
         kfree(vol_args);
+        kfree(inherit);
         return ret;
 }
 
@@ -3588,6 +3611,8 @@ long btrfs_ioctl(struct file *file, unsigned int
                 return btrfs_ioctl_snap_create_v2(file, argp, 0);
         case BTRFS_IOC_SUBVOL_CREATE:
                 return btrfs_ioctl_snap_create(file, argp, 1);
+        case BTRFS_IOC_SUBVOL_CREATE_V2:
+                return btrfs_ioctl_snap_create_v2(file, argp, 1);
         case BTRFS_IOC_SNAP_DESTROY:
                 return btrfs_ioctl_snap_destroy(file, argp);
         case BTRFS_IOC_SUBVOL_GETFLAGS:
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 9dd50c4656b3..cdda57f1c240 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -32,6 +32,7 @@ struct btrfs_ioctl_vol_args {
 
 #define BTRFS_SUBVOL_CREATE_ASYNC       (1ULL << 0)
 #define BTRFS_SUBVOL_RDONLY             (1ULL << 1)
+#define BTRFS_SUBVOL_QGROUP_INHERIT     (1ULL << 2)
 #define BTRFS_FSID_SIZE 16
 #define BTRFS_UUID_SIZE 16
 
@@ -64,7 +65,13 @@ struct btrfs_ioctl_vol_args_v2 {
         __s64 fd;
         __u64 transid;
         __u64 flags;
-        __u64 unused[4];
+        union {
+                struct {
+                        __u64 size;
+                        struct btrfs_qgroup_inherit __user *qgroup_inherit;
+                };
+                __u64 unused[4];
+        };
         char name[BTRFS_SUBVOL_NAME_MAX + 1];
 };
 
@@ -382,6 +389,8 @@ struct btrfs_ioctl_qgroup_create_args {
 #define BTRFS_IOC_WAIT_SYNC  _IOW(BTRFS_IOCTL_MAGIC, 22, __u64)
 #define BTRFS_IOC_SNAP_CREATE_V2 _IOW(BTRFS_IOCTL_MAGIC, 23, \
                                    struct btrfs_ioctl_vol_args_v2)
+#define BTRFS_IOC_SUBVOL_CREATE_V2 _IOW(BTRFS_IOCTL_MAGIC, 24, \
+                                   struct btrfs_ioctl_vol_args_v2)
 #define BTRFS_IOC_SUBVOL_GETFLAGS _IOR(BTRFS_IOCTL_MAGIC, 25, __u64)
 #define BTRFS_IOC_SUBVOL_SETFLAGS _IOW(BTRFS_IOCTL_MAGIC, 26, __u64)
 #define BTRFS_IOC_SCRUB _IOWR(BTRFS_IOCTL_MAGIC, 27, \
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index f1e29fbd5317..127283913a42 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -990,6 +990,14 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
                 }
         }
 
+        ret = btrfs_qgroup_inherit(trans, fs_info, root->root_key.objectid,
+                                   objectid, pending->inherit);
+        kfree(pending->inherit);
+        if (ret) {
+                pending->error = ret;
+                goto fail;
+        }
+
         key.objectid = objectid;
         key.offset = (u64)-1;
         key.type = BTRFS_ROOT_ITEM_KEY;
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 2759e0572c5c..cca315dcdfcd 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -73,6 +73,7 @@ struct btrfs_pending_snapshot {
         struct dentry *dentry;
         struct btrfs_root *root;
         struct btrfs_root *snap;
+        struct btrfs_qgroup_inherit *inherit;
         /* block reservation for the operation */
         struct btrfs_block_rsv block_rsv;
         /* extra metadata reseration for relocation */