Merge tag 'pull-revalidate' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs d_revalidate updates from Al Viro:
 "Provide stable parent and name to ->d_revalidate() instances

  Most of the filesystem methods where we care about dentry name and
  parent have their stability guaranteed by the callers;
  ->d_revalidate() is the major exception.

  It's easy enough for callers to supply stable values for expected name
  and expected parent of the dentry being validated. That kills quite a
  bit of boilerplate in ->d_revalidate() instances, along with a bunch
  of races where they used to access ->d_name without sufficient
  precautions"

* tag 'pull-revalidate' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  9p: fix ->rename_sem exclusion
  orangefs_d_revalidate(): use stable parent inode and name passed by caller
  ocfs2_dentry_revalidate(): use stable parent inode and name passed by caller
  nfs: fix ->d_revalidate() UAF on ->d_name accesses
  nfs{,4}_lookup_validate(): use stable parent inode passed by caller
  gfs2_drevalidate(): use stable parent inode and name passed by caller
  fuse_dentry_revalidate(): use stable parent inode and name passed by caller
  vfat_revalidate{,_ci}(): use stable parent inode passed by caller
  exfat_d_revalidate(): use stable parent inode passed by caller
  fscrypt_d_revalidate(): use stable parent inode passed by caller
  ceph_d_revalidate(): propagate stable name down into request encoding
  ceph_d_revalidate(): use stable parent inode passed by caller
  afs_d_revalidate(): use stable name and parent inode passed by caller
  Pass parent directory inode and expected name to ->d_revalidate()
  generic_ci_d_compare(): use shortname_storage
  ext4 fast_commit: make use of name_snapshot primitives
  dissolve external_name.u into separate members
  make take_dentry_name_snapshot() lockless
  dcache: back inline names with a struct-wrapped array of unsigned long
  make sure that DNAME_INLINE_LEN is a multiple of word size

1 files changed, 5 insertions, 24 deletions

diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index 26c4fc37edcf..da4263a14a20 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -322,9 +322,7 @@ restart:
 	WARN_ON(!list_empty(&ei->i_fc_dilist));
 	spin_unlock(&sbi->s_fc_lock);
 
-	if (fc_dentry->fcd_name.name &&
-		fc_dentry->fcd_name.len > DNAME_INLINE_LEN)
-		kfree(fc_dentry->fcd_name.name);
+	release_dentry_name_snapshot(&fc_dentry->fcd_name);
 	kmem_cache_free(ext4_fc_dentry_cachep, fc_dentry);
 
 	return;
@@ -449,22 +447,7 @@ static int __track_dentry_update(handle_t *handle, struct inode *inode,
 	node->fcd_op = dentry_update->op;
 	node->fcd_parent = dir->i_ino;
 	node->fcd_ino = inode->i_ino;
-	if (dentry->d_name.len > DNAME_INLINE_LEN) {
-		node->fcd_name.name = kmalloc(dentry->d_name.len, GFP_NOFS);
-		if (!node->fcd_name.name) {
-			kmem_cache_free(ext4_fc_dentry_cachep, node);
-			ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_NOMEM, handle);
-			mutex_lock(&ei->i_fc_lock);
-			return -ENOMEM;
-		}
-		memcpy((u8 *)node->fcd_name.name, dentry->d_name.name,
-			dentry->d_name.len);
-	} else {
-		memcpy(node->fcd_iname, dentry->d_name.name,
-			dentry->d_name.len);
-		node->fcd_name.name = node->fcd_iname;
-	}
-	node->fcd_name.len = dentry->d_name.len;
+	take_dentry_name_snapshot(&node->fcd_name, dentry);
 	INIT_LIST_HEAD(&node->fcd_dilist);
 	spin_lock(&sbi->s_fc_lock);
 	if (sbi->s_journal->j_flags & JBD2_FULL_COMMIT_ONGOING ||
@@ -832,7 +815,7 @@ static bool ext4_fc_add_dentry_tlv(struct super_block *sb, u32 *crc,
 {
 	struct ext4_fc_dentry_info fcd;
 	struct ext4_fc_tl tl;
-	int dlen = fc_dentry->fcd_name.len;
+	int dlen = fc_dentry->fcd_name.name.len;
 	u8 *dst = ext4_fc_reserve_space(sb,
 			EXT4_FC_TAG_BASE_LEN + sizeof(fcd) + dlen, crc);
 
@@ -847,7 +830,7 @@ static bool ext4_fc_add_dentry_tlv(struct super_block *sb, u32 *crc,
 	dst += EXT4_FC_TAG_BASE_LEN;
 	memcpy(dst, &fcd, sizeof(fcd));
 	dst += sizeof(fcd);
-	memcpy(dst, fc_dentry->fcd_name.name, dlen);
+	memcpy(dst, fc_dentry->fcd_name.name.name, dlen);
 
 	return true;
 }
@@ -1328,9 +1311,7 @@ static void ext4_fc_cleanup(journal_t *journal, int full, tid_t tid)
 		list_del_init(&fc_dentry->fcd_dilist);
 		spin_unlock(&sbi->s_fc_lock);
 
-		if (fc_dentry->fcd_name.name &&
-			fc_dentry->fcd_name.len > DNAME_INLINE_LEN)
-			kfree(fc_dentry->fcd_name.name);
+		release_dentry_name_snapshot(&fc_dentry->fcd_name);
 		kmem_cache_free(ext4_fc_dentry_cachep, fc_dentry);
 		spin_lock(&sbi->s_fc_lock);
 	}