add jffs2 whiteout support (necessary for using it with union mounts)

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@17745 3c298f89-4303-0410-b956-a3cf2f4a3e73

diff --git a/target/linux/generic-2.6/patches-2.6.31/233-jffs2_whiteout_support.patch b/target/linux/generic-2.6/patches-2.6.31/233-jffs2_whiteout_support.patch
new file mode 100644 (file)
index 0000000..72a4282
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.31/233-jffs2_whiteout_support.patch
@@ -0,0 +1,186 @@
+--- a/fs/jffs2/dir.c
++++ b/fs/jffs2/dir.c
+@@ -34,6 +34,9 @@
+ static int jffs2_rename (struct inode *, struct dentry *,
+                        struct inode *, struct dentry *);
+ 
++static int jffs2_whiteout (struct inode *, struct dentry *, struct dentry *);
++static int jffs2_fallthru (struct inode *, struct dentry *);
++
+ const struct file_operations jffs2_dir_operations =
+ {
+       .read =         generic_read_dir,
+@@ -55,6 +58,8 @@
+       .rmdir =        jffs2_rmdir,
+       .mknod =        jffs2_mknod,
+       .rename =       jffs2_rename,
++      .fallthru =     jffs2_fallthru,
++      .whiteout =     jffs2_whiteout,
+       .permission =   jffs2_permission,
+       .setattr =      jffs2_setattr,
+       .setxattr =     jffs2_setxattr,
+@@ -98,8 +103,21 @@
+                       fd = fd_list;
+               }
+       }
+-      if (fd)
+-              ino = fd->ino;
++      if (fd) {
++              spin_lock(&target->d_lock);
++              switch(fd->type) {
++              case DT_WHT:
++                      target->d_flags |= DCACHE_WHITEOUT;
++                      break;
++              case DT_UNKNOWN:
++                      target->d_flags |= DCACHE_FALLTHRU;
++                      break;
++              default:
++                      ino = fd->ino;
++                      break;
++              }
++              spin_unlock(&target->d_lock);
++      }
+       mutex_unlock(&dir_f->sem);
+       if (ino) {
+               inode = jffs2_iget(dir_i->i_sb, ino);
+@@ -155,7 +173,9 @@
+                                 fd->name, fd->ino, fd->type, curofs, offset));
+                       continue;
+               }
+-              if (!fd->ino) {
++              if (fd->type == DT_UNKNOWN)
++                      fd->ino = 100; /* XXX: arbitrary */
++              else if (!fd->ino && (fd->type != DT_WHT)) {
+                       D2(printk(KERN_DEBUG "Skipping deletion dirent \"%s\"\n", fd->name));
+                       offset++;
+                       continue;
+@@ -498,6 +518,11 @@
+               return PTR_ERR(inode);
+       }
+ 
++      if (dentry->d_flags & DCACHE_WHITEOUT) {
++              inode->i_flags |= S_OPAQUE;
++              ri->flags = cpu_to_je16(JFFS2_INO_FLAG_OPAQUE);
++      }
++
+       inode->i_op = &jffs2_dir_inode_operations;
+       inode->i_fop = &jffs2_dir_operations;
+ 
+@@ -779,6 +804,82 @@
+       return 0;
+ }
+ 
++static int jffs2_fallthru (struct inode *dir, struct dentry *dentry)
++{
++      struct jffs2_sb_info *c = JFFS2_SB_INFO(dir->i_sb);
++      uint32_t now;
++      int ret;
++
++      now = get_seconds();
++      ret = jffs2_do_link(c, JFFS2_INODE_INFO(dir), 0, DT_UNKNOWN,
++                          dentry->d_name.name, dentry->d_name.len, now);
++      if (ret)
++              return ret;
++
++      d_instantiate(dentry, NULL);
++      spin_lock(&dentry->d_lock);
++      dentry->d_flags |= DCACHE_FALLTHRU;
++      spin_unlock(&dentry->d_lock);
++
++      return 0;
++}
++
++static int jffs2_whiteout (struct inode *dir, struct dentry *old_dentry,
++                         struct dentry *new_dentry)
++{
++      struct jffs2_sb_info *c = JFFS2_SB_INFO(dir->i_sb);
++      struct jffs2_inode_info *victim_f = NULL;
++      uint32_t now;
++      int ret;
++
++      /* If it's a directory, then check whether it is really empty
++       */
++      if (new_dentry->d_inode) {
++              victim_f = JFFS2_INODE_INFO(old_dentry->d_inode);
++              if (S_ISDIR(old_dentry->d_inode->i_mode)) {
++                      struct jffs2_full_dirent *fd;
++
++                      mutex_lock(&victim_f->sem);
++                      for (fd = victim_f->dents; fd; fd = fd->next) {
++                              if (fd->ino) {
++                                      mutex_unlock(&victim_f->sem);
++                                      return -ENOTEMPTY;
++                              }
++                      }
++                      mutex_unlock(&victim_f->sem);
++              }
++      }
++
++      now = get_seconds();
++      ret = jffs2_do_link(c, JFFS2_INODE_INFO(dir), 0, DT_WHT,
++                          new_dentry->d_name.name, new_dentry->d_name.len, now);
++      if (ret)
++              return ret;
++
++      spin_lock(&new_dentry->d_lock);
++      new_dentry->d_flags &= ~DCACHE_FALLTHRU;
++      new_dentry->d_flags |= DCACHE_WHITEOUT;
++      spin_unlock(&new_dentry->d_lock);
++      d_add(new_dentry, NULL);
++
++      if (victim_f) {
++              /* There was a victim. Kill it off nicely */
++              drop_nlink(old_dentry->d_inode);
++              /* Don't oops if the victim was a dirent pointing to an
++                 inode which didn't exist. */
++              if (victim_f->inocache) {
++                      mutex_lock(&victim_f->sem);
++                      if (S_ISDIR(old_dentry->d_inode->i_mode))
++                              victim_f->inocache->pino_nlink = 0;
++                      else
++                              victim_f->inocache->pino_nlink--;
++                      mutex_unlock(&victim_f->sem);
++              }
++      }
++
++      return 0;
++}
++
+ static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
+                        struct inode *new_dir_i, struct dentry *new_dentry)
+ {
+--- a/fs/jffs2/fs.c
++++ b/fs/jffs2/fs.c
+@@ -301,6 +301,10 @@
+ 
+               inode->i_op = &jffs2_dir_inode_operations;
+               inode->i_fop = &jffs2_dir_operations;
++
++              if (je16_to_cpu(latest_node.flags) & JFFS2_INO_FLAG_OPAQUE)
++                      inode->i_flags |= S_OPAQUE;
++
+               break;
+       }
+       case S_IFREG:
+--- a/fs/jffs2/super.c
++++ b/fs/jffs2/super.c
+@@ -172,7 +172,7 @@
+ 
+       sb->s_op = &jffs2_super_operations;
+       sb->s_export_op = &jffs2_export_ops;
+-      sb->s_flags = sb->s_flags | MS_NOATIME;
++      sb->s_flags = sb->s_flags | MS_NOATIME | MS_WHITEOUT;
+       sb->s_xattr = jffs2_xattr_handlers;
+ #ifdef CONFIG_JFFS2_FS_POSIX_ACL
+       sb->s_flags |= MS_POSIXACL;
+--- a/include/linux/jffs2.h
++++ b/include/linux/jffs2.h
+@@ -87,6 +87,8 @@
+ #define JFFS2_INO_FLAG_USERCOMPR  2   /* User has requested a specific
+                                          compression type */
+ 
++#define JFFS2_INO_FLAG_OPAQUE     4   /* Directory is opaque (for union mounts) */
++
+ 
+ /* These can go once we've made sure we've caught all uses without
+    byteswapping */