nilfs2: implement resize ioctl

This adds resize ioctl which makes online resize possible.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

1 files changed, 72 insertions, 0 deletions

diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index eba5b53b1080..2846491071ce 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -56,6 +56,7 @@
 #include "btnode.h"
 #include "page.h"
 #include "cpfile.h"
+#include "sufile.h" /* nilfs_sufile_resize(), nilfs_sufile_set_alloc_range() */
 #include "ifile.h"
 #include "dat.h"
 #include "segment.h"
@@ -404,6 +405,77 @@ out:
         return ret;
 }
 
+/**
+ * nilfs_resize_fs - resize the filesystem
+ * @sb: super block instance
+ * @newsize: new size of the filesystem (in bytes)
+ */
+int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
+{
+        struct the_nilfs *nilfs = sb->s_fs_info;
+        struct nilfs_super_block **sbp;
+        __u64 devsize, newnsegs;
+        loff_t sb2off;
+        int ret;
+
+        ret = -ERANGE;
+        devsize = i_size_read(sb->s_bdev->bd_inode);
+        if (newsize > devsize)
+                goto out;
+
+        /*
+         * Write lock is required to protect some functions depending
+         * on the number of segments, the number of reserved segments,
+         * and so forth.
+         */
+        down_write(&nilfs->ns_segctor_sem);
+
+        sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
+        newnsegs = sb2off >> nilfs->ns_blocksize_bits;
+        do_div(newnsegs, nilfs->ns_blocks_per_segment);
+
+        ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
+        up_write(&nilfs->ns_segctor_sem);
+        if (ret < 0)
+                goto out;
+
+        ret = nilfs_construct_segment(sb);
+        if (ret < 0)
+                goto out;
+
+        down_write(&nilfs->ns_sem);
+        nilfs_move_2nd_super(sb, sb2off);
+        ret = -EIO;
+        sbp = nilfs_prepare_super(sb, 0);
+        if (likely(sbp)) {
+                nilfs_set_log_cursor(sbp[0], nilfs);
+                /*
+                 * Drop NILFS_RESIZE_FS flag for compatibility with
+                 * mount-time resize which may be implemented in a
+                 * future release.
+                 */
+                sbp[0]->s_state = cpu_to_le16(le16_to_cpu(sbp[0]->s_state) &
+                                              ~NILFS_RESIZE_FS);
+                sbp[0]->s_dev_size = cpu_to_le64(newsize);
+                sbp[0]->s_nsegments = cpu_to_le64(nilfs->ns_nsegments);
+                if (sbp[1])
+                        memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
+                ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
+        }
+        up_write(&nilfs->ns_sem);
+
+        /*
+         * Reset the range of allocatable segments last.  This order
+         * is important in the case of expansion because the secondary
+         * superblock must be protected from log write until migration
+         * completes.
+         */
+        if (!ret)
+                nilfs_sufile_set_alloc_range(nilfs->ns_sufile, 0, newnsegs - 1);
+out:
+        return ret;
+}
+
 static void nilfs_put_super(struct super_block *sb)
 {
         struct the_nilfs *nilfs = sb->s_fs_info;