Btrfs: Per file/directory controls for COW and compression

[linux-2.6-block.git] / fs / btrfs / ioctl.c

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 88d3cb2eaf75ecf10d660f83bacb9543d22fb007..32c980ae0f1c63a601681df1273fa9c6bb4db1cd 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -138,6 +138,24 @@ static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
        return 0;
 }
 
+static int check_flags(unsigned int flags)
+{
+       if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
+                     FS_NOATIME_FL | FS_NODUMP_FL | \
+                     FS_SYNC_FL | FS_DIRSYNC_FL | \
+                     FS_NOCOMP_FL | FS_COMPR_FL | \
+                     FS_NOCOW_FL | FS_COW_FL))
+               return -EOPNOTSUPP;
+
+       if ((flags & FS_NOCOMP_FL) && (flags & FS_COMPR_FL))
+               return -EINVAL;
+
+       if ((flags & FS_NOCOW_FL) && (flags & FS_COW_FL))
+               return -EINVAL;
+
+       return 0;
+}
+
 static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 {
        struct inode *inode = file->f_path.dentry->d_inode;
@@ -153,10 +171,9 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
        if (copy_from_user(&flags, arg, sizeof(flags)))
                return -EFAULT;
 
-       if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
-                     FS_NOATIME_FL | FS_NODUMP_FL | \
-                     FS_SYNC_FL | FS_DIRSYNC_FL))
-               return -EOPNOTSUPP;
+       ret = check_flags(flags);
+       if (ret)
+               return ret;
 
        if (!is_owner_or_cap(inode))
                return -EACCES;
@@ -201,6 +218,22 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
        else
                ip->flags &= ~BTRFS_INODE_DIRSYNC;
 
+       /*
+        * The COMPRESS flag can only be changed by users, while the NOCOMPRESS
+        * flag may be changed automatically if compression code won't make
+        * things smaller.
+        */
+       if (flags & FS_NOCOMP_FL) {
+               ip->flags &= ~BTRFS_INODE_COMPRESS;
+               ip->flags |= BTRFS_INODE_NOCOMPRESS;
+       } else if (flags & FS_COMPR_FL) {
+               ip->flags |= BTRFS_INODE_COMPRESS;
+               ip->flags &= ~BTRFS_INODE_NOCOMPRESS;
+       }
+       if (flags & FS_NOCOW_FL)
+               ip->flags |= BTRFS_INODE_NODATACOW;
+       else if (flags & FS_COW_FL)
+               ip->flags &= ~BTRFS_INODE_NODATACOW;
 
        trans = btrfs_join_transaction(root, 1);
        BUG_ON(IS_ERR(trans));