nilfs2: add ioctl which limits range of segment to be allocated
This adds a new ioctl command which limits range of segment to be
allocated. This is intended to gather data whithin a range of the
partition before shrinking the filesystem, or to control new log
location for some purpose.
If a range is specified by the ioctl, segment allocator of nilfs tries
to allocate new segments from the range unless no free segments are
available there.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index f2469ba..6f61777 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -698,6 +698,38 @@
return 0;
}
+static int nilfs_ioctl_set_alloc_range(struct inode *inode, void __user *argp)
+{
+ struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
+ __u64 range[2];
+ __u64 minseg, maxseg;
+ unsigned long segbytes;
+ int ret = -EPERM;
+
+ if (!capable(CAP_SYS_ADMIN))
+ goto out;
+
+ ret = -EFAULT;
+ if (copy_from_user(range, argp, sizeof(__u64[2])))
+ goto out;
+
+ ret = -ERANGE;
+ if (range[1] > i_size_read(inode->i_sb->s_bdev->bd_inode))
+ goto out;
+
+ segbytes = nilfs->ns_blocks_per_segment * nilfs->ns_blocksize;
+
+ minseg = range[0] + segbytes - 1;
+ do_div(minseg, segbytes);
+ maxseg = NILFS_SB2_OFFSET_BYTES(range[1]);
+ do_div(maxseg, segbytes);
+ maxseg--;
+
+ ret = nilfs_sufile_set_alloc_range(nilfs->ns_sufile, minseg, maxseg);
+out:
+ return ret;
+}
+
static int nilfs_ioctl_get_info(struct inode *inode, struct file *filp,
unsigned int cmd, void __user *argp,
size_t membsz,
@@ -763,6 +795,8 @@
return nilfs_ioctl_clean_segments(inode, filp, cmd, argp);
case NILFS_IOCTL_SYNC:
return nilfs_ioctl_sync(inode, filp, cmd, argp);
+ case NILFS_IOCTL_SET_ALLOC_RANGE:
+ return nilfs_ioctl_set_alloc_range(inode, argp);
default:
return -ENOTTY;
}