nilfs2: implement resize ioctl
This adds resize ioctl which makes online resize possible.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/sufile.c b/fs/nilfs2/sufile.c
index 22f2e6e..37b9631 100644
--- a/fs/nilfs2/sufile.c
+++ b/fs/nilfs2/sufile.c
@@ -722,6 +722,73 @@
}
/**
+ * nilfs_sufile_resize - resize segment array
+ * @sufile: inode of segment usage file
+ * @newnsegs: new number of segments
+ *
+ * Return Value: On success, 0 is returned. On error, one of the
+ * following negative error codes is returned.
+ *
+ * %-EIO - I/O error.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ *
+ * %-ENOSPC - Enough free space is not left for shrinking
+ *
+ * %-EBUSY - Dirty or active segments exist in the region to be truncated
+ */
+int nilfs_sufile_resize(struct inode *sufile, __u64 newnsegs)
+{
+ struct the_nilfs *nilfs = sufile->i_sb->s_fs_info;
+ struct buffer_head *header_bh;
+ struct nilfs_sufile_header *header;
+ struct nilfs_sufile_info *sui = NILFS_SUI(sufile);
+ void *kaddr;
+ unsigned long nsegs, nrsvsegs;
+ int ret = 0;
+
+ down_write(&NILFS_MDT(sufile)->mi_sem);
+
+ nsegs = nilfs_sufile_get_nsegments(sufile);
+ if (nsegs == newnsegs)
+ goto out;
+
+ ret = -ENOSPC;
+ nrsvsegs = nilfs_nrsvsegs(nilfs, newnsegs);
+ if (newnsegs < nsegs && nsegs - newnsegs + nrsvsegs > sui->ncleansegs)
+ goto out;
+
+ ret = nilfs_sufile_get_header_block(sufile, &header_bh);
+ if (ret < 0)
+ goto out;
+
+ if (newnsegs > nsegs) {
+ sui->ncleansegs += newnsegs - nsegs;
+ } else /* newnsegs < nsegs */ {
+ ret = nilfs_sufile_truncate_range(sufile, newnsegs, nsegs - 1);
+ if (ret < 0)
+ goto out_header;
+
+ sui->ncleansegs -= nsegs - newnsegs;
+ }
+
+ kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
+ header = kaddr + bh_offset(header_bh);
+ header->sh_ncleansegs = cpu_to_le64(sui->ncleansegs);
+ kunmap_atomic(kaddr, KM_USER0);
+
+ nilfs_mdt_mark_buffer_dirty(header_bh);
+ nilfs_mdt_mark_dirty(sufile);
+ nilfs_set_nsegments(nilfs, newnsegs);
+
+out_header:
+ brelse(header_bh);
+out:
+ up_write(&NILFS_MDT(sufile)->mi_sem);
+ return ret;
+}
+
+/**
* nilfs_sufile_get_suinfo -
* @sufile: inode of segment usage file
* @segnum: segment number to start looking