ext4: hook the ext3 migration interface to the EXT4_IOC_SETFLAGS ioctl

This patch hooks the ext3 to ext4 migrate interface to
EXT4_IOC_SETFLAGS ioctl. The userspace interface is via chattr +e.  We
only allow setting extent flags.  Clearing extent flag (migrating from
ext4 to ext3) is not supported.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 9b6ad8f19bc9560b5385287f4260564baf8cfae2..068adc1d5607a31449c7caa4d187d3e94c5c110f 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -245,7 +245,7 @@ struct flex_groups {
 #define EXT4_RESERVED_FL               0x80000000 /* reserved for ext4 lib */
 
 #define EXT4_FL_USER_VISIBLE           0x000BDFFF /* User visible flags */
-#define EXT4_FL_USER_MODIFIABLE                0x000380FF /* User modifiable flags */
+#define EXT4_FL_USER_MODIFIABLE                0x000B80FF /* User modifiable flags */
 
 /*
  * Inode dynamic state flags

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 9f3044ac6994a52e7be4211f185f8c81665e296b..3e14060b398e38bfca85495d02e5cae4862c3a11 100644 (file)
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -34,7 +34,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                return put_user(flags, (int __user *) arg);
        case EXT4_IOC_SETFLAGS: {
                handle_t *handle = NULL;
-               int err;
+               int err, migrate = 0;
                struct ext4_iloc iloc;
                unsigned int oldflags;
                unsigned int jflag;
@@ -82,6 +82,17 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                        if (!capable(CAP_SYS_RESOURCE))
                                goto flags_out;
                }
+               if (oldflags & EXT4_EXTENTS_FL) {
+                       /* We don't support clearning extent flags */
+                       if (!(flags & EXT4_EXTENTS_FL)) {
+                               err = -EOPNOTSUPP;
+                               goto flags_out;
+                       }
+               } else if (flags & EXT4_EXTENTS_FL) {
+                       /* migrate the file */
+                       migrate = 1;
+                       flags &= ~EXT4_EXTENTS_FL;
+               }
 
                handle = ext4_journal_start(inode, 1);
                if (IS_ERR(handle)) {
@@ -109,6 +120,10 @@ flags_err:
 
                if ((jflag ^ oldflags) & (EXT4_JOURNAL_DATA_FL))
                        err = ext4_change_inode_journal_flag(inode, jflag);
+               if (err)
+                       goto flags_out;
+               if (migrate)
+                       err = ext4_ext_migrate(inode);
 flags_out:
                mutex_unlock(&inode->i_mutex);
                mnt_drop_write(filp->f_path.mnt);