kernel: fix an overlayfs deadlock on rmdir

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@26215 3c298f89-4303-0410-b956-a3cf2f4a3e73

diff --git a/target/linux/generic/patches-2.6.37/212-overlayfs_fix_readdir_unlink_deadlock.patch b/target/linux/generic/patches-2.6.37/212-overlayfs_fix_readdir_unlink_deadlock.patch
new file mode 100644 (file)
index 0000000..6042b29
--- /dev/null
+++ b/target/linux/generic/patches-2.6.37/212-overlayfs_fix_readdir_unlink_deadlock.patch
@@ -0,0 +1,76 @@
+--- a/fs/overlayfs/overlayfs.c
++++ b/fs/overlayfs/overlayfs.c
+@@ -1686,37 +1686,56 @@ static int ovl_check_empty_dir(struct de
+       return err;
+ }
+ 
+-static int ovl_unlink_whiteout(void *buf, const char *name, int namelen,
+-                               loff_t offset, u64 ino, unsigned int d_type)
++static int ovl_fill_links(void *buf, const char *name, int namelen,
++                          loff_t offset, u64 ino, unsigned int d_type)
+ {
+       struct ovl_readdir_data *rdd = buf;
++      struct ovl_cache_entry *p;
+ 
+-      rdd->count++;
+-      /* check d_type to filter out "." and ".." */
+-      if (d_type == DT_LNK) {
+-              struct dentry *dentry;
++      if (d_type != DT_LNK)
++              return 0;
+ 
+-              dentry = lookup_one_len(name, rdd->dir, namelen);
+-              if (IS_ERR(dentry)) {
+-                      rdd->err = PTR_ERR(dentry);
+-              } else {
+-                      rdd->err = vfs_unlink(rdd->dir->d_inode, dentry);
+-                      dput(dentry);
+-              }
+-      }
++      p = ovl_cache_entry_new(name, namelen, ino, d_type);
++      if (!p)
++              return -ENOMEM;
+ 
+-      return rdd->err;
++      list_add(&p->l_node, rdd->list);
++      return 0;
+ }
+ 
+ static int ovl_remove_whiteouts(struct dentry *dentry)
+ {
+       struct path upperpath;
+-      struct ovl_readdir_data rdd = { .list = NULL };
++      LIST_HEAD(list);
++      struct ovl_readdir_data rdd = { .list = &list };
++      struct ovl_cache_entry *p, *t;
++      int ret;
+ 
+       ovl_path_upper(dentry, &upperpath);
+       rdd.dir = upperpath.dentry;
+ 
+-      return ovl_dir_read(&upperpath, &rdd, ovl_unlink_whiteout);
++      ret = ovl_dir_read(&upperpath, &rdd, ovl_fill_links);
++
++      mutex_lock(&rdd.dir->d_inode->i_mutex);
++      list_for_each_entry_safe(p, t, &list, l_node) {
++              struct dentry *dentry;
++
++              if (!ret) {
++                      dentry = lookup_one_len(p->name, rdd.dir, p->len);
++                      if (IS_ERR(dentry)) {
++                              ret = PTR_ERR(dentry);
++                      } else {
++                              ret = vfs_unlink(rdd.dir->d_inode, dentry);
++                              dput(dentry);
++                      }
++              }
++
++              list_del(&p->l_node);
++              kfree(p);
++      }
++      mutex_unlock(&rdd.dir->d_inode->i_mutex);
++
++      return ret;
+ }
+ 
+ static int ovl_rmdir(struct inode *dir, struct dentry *dentry)

diff --git a/target/linux/generic/patches-2.6.38/211-overlayfs_fix_readdir_unlink_deadlock.patch b/target/linux/generic/patches-2.6.38/211-overlayfs_fix_readdir_unlink_deadlock.patch
new file mode 100644 (file)
index 0000000..6f4ceb4
--- /dev/null
+++ b/target/linux/generic/patches-2.6.38/211-overlayfs_fix_readdir_unlink_deadlock.patch
@@ -0,0 +1,76 @@
+--- a/fs/overlayfs/overlayfs.c
++++ b/fs/overlayfs/overlayfs.c
+@@ -1700,37 +1700,56 @@ static int ovl_check_empty_dir(struct de
+       return err;
+ }
+ 
+-static int ovl_unlink_whiteout(void *buf, const char *name, int namelen,
+-                               loff_t offset, u64 ino, unsigned int d_type)
++static int ovl_fill_links(void *buf, const char *name, int namelen,
++                          loff_t offset, u64 ino, unsigned int d_type)
+ {
+       struct ovl_readdir_data *rdd = buf;
++      struct ovl_cache_entry *p;
+ 
+-      rdd->count++;
+-      /* check d_type to filter out "." and ".." */
+-      if (d_type == DT_LNK) {
+-              struct dentry *dentry;
++      if (d_type != DT_LNK)
++              return 0;
+ 
+-              dentry = lookup_one_len(name, rdd->dir, namelen);
+-              if (IS_ERR(dentry)) {
+-                      rdd->err = PTR_ERR(dentry);
+-              } else {
+-                      rdd->err = vfs_unlink(rdd->dir->d_inode, dentry);
+-                      dput(dentry);
+-              }
+-      }
++      p = ovl_cache_entry_new(name, namelen, ino, d_type);
++      if (!p)
++              return -ENOMEM;
+ 
+-      return rdd->err;
++      list_add(&p->l_node, rdd->list);
++      return 0;
+ }
+ 
+ static int ovl_remove_whiteouts(struct dentry *dentry)
+ {
+       struct path upperpath;
+-      struct ovl_readdir_data rdd = { .list = NULL };
++      LIST_HEAD(list);
++      struct ovl_readdir_data rdd = { .list = &list };
++      struct ovl_cache_entry *p, *t;
++      int ret;
+ 
+       ovl_path_upper(dentry, &upperpath);
+       rdd.dir = upperpath.dentry;
+ 
+-      return ovl_dir_read(&upperpath, &rdd, ovl_unlink_whiteout);
++      ret = ovl_dir_read(&upperpath, &rdd, ovl_fill_links);
++
++      mutex_lock(&rdd.dir->d_inode->i_mutex);
++      list_for_each_entry_safe(p, t, &list, l_node) {
++              struct dentry *dentry;
++
++              if (!ret) {
++                      dentry = lookup_one_len(p->name, rdd.dir, p->len);
++                      if (IS_ERR(dentry)) {
++                              ret = PTR_ERR(dentry);
++                      } else {
++                              ret = vfs_unlink(rdd.dir->d_inode, dentry);
++                              dput(dentry);
++                      }
++              }
++
++              list_del(&p->l_node);
++              kfree(p);
++      }
++      mutex_unlock(&rdd.dir->d_inode->i_mutex);
++
++      return ret;
+ }
+ 
+ static int ovl_rmdir(struct inode *dir, struct dentry *dentry)