Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
 "Various bug fixes and cleanups for ext4.

  In particular, move the crypto related fucntions from fs/ext4/super.c
  into a new fs/ext4/crypto.c, and fix a number of bugs found by fuzzers
  and error injection tools"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (25 commits)
  ext4: only allow test_dummy_encryption when supported
  ext4: fix bug_on in __es_tree_search
  ext4: avoid cycles in directory h-tree
  ext4: verify dir block before splitting it
  ext4: filter out EXT4_FC_REPLAY from on-disk superblock field s_state
  ext4: fix bug_on in ext4_writepages
  ext4: refactor and move ext4_ioctl_get_encryption_pwsalt()
  ext4: cleanup function defs from ext4.h into crypto.c
  ext4: move ext4 crypto code to its own file crypto.c
  ext4: fix memory leak in parse_apply_sb_mount_options()
  ext4: reject the 'commit' option on ext2 filesystems
  ext4: remove duplicated #include of dax.h in inode.c
  ext4: fix race condition between ext4_write and ext4_convert_inline_data
  ext4: convert symlink external data block mapping to bdev
  ext4: add nowait mode for ext4_getblk()
  ext4: fix journal_ioprio mount option handling
  ext4: mark group as trimmed only if it was fully scanned
  ext4: fix use-after-free in ext4_rename_dir_prepare
  ext4: add unmount filesystem message
  ext4: remove unnecessary conditionals
  ...

1 files changed, 43 insertions, 8 deletions

diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
index 69109746e6e2..d281f5bcc526 100644
--- a/fs/ext4/symlink.c
+++ b/fs/ext4/symlink.c
@@ -27,7 +27,7 @@ static const char *ext4_encrypted_get_link(struct dentry *dentry,
 					   struct inode *inode,
 					   struct delayed_call *done)
 {
-	struct page *cpage = NULL;
+	struct buffer_head *bh = NULL;
 	const void *caddr;
 	unsigned int max_size;
 	const char *paddr;
@@ -39,16 +39,19 @@ static const char *ext4_encrypted_get_link(struct dentry *dentry,
 		caddr = EXT4_I(inode)->i_data;
 		max_size = sizeof(EXT4_I(inode)->i_data);
 	} else {
-		cpage = read_mapping_page(inode->i_mapping, 0, NULL);
-		if (IS_ERR(cpage))
-			return ERR_CAST(cpage);
-		caddr = page_address(cpage);
+		bh = ext4_bread(NULL, inode, 0, 0);
+		if (IS_ERR(bh))
+			return ERR_CAST(bh);
+		if (!bh) {
+			EXT4_ERROR_INODE(inode, "bad symlink.");
+			return ERR_PTR(-EFSCORRUPTED);
+		}
+		caddr = bh->b_data;
 		max_size = inode->i_sb->s_blocksize;
 	}
 
 	paddr = fscrypt_get_symlink(inode, caddr, max_size, done);
-	if (cpage)
-		put_page(cpage);
+	brelse(bh);
 	return paddr;
 }
 
@@ -62,6 +65,38 @@ static int ext4_encrypted_symlink_getattr(struct user_namespace *mnt_userns,
 	return fscrypt_symlink_getattr(path, stat);
 }
 
+static void ext4_free_link(void *bh)
+{
+	brelse(bh);
+}
+
+static const char *ext4_get_link(struct dentry *dentry, struct inode *inode,
+				 struct delayed_call *callback)
+{
+	struct buffer_head *bh;
+
+	if (!dentry) {
+		bh = ext4_getblk(NULL, inode, 0, EXT4_GET_BLOCKS_CACHED_NOWAIT);
+		if (IS_ERR(bh))
+			return ERR_CAST(bh);
+		if (!bh || !ext4_buffer_uptodate(bh))
+			return ERR_PTR(-ECHILD);
+	} else {
+		bh = ext4_bread(NULL, inode, 0, 0);
+		if (IS_ERR(bh))
+			return ERR_CAST(bh);
+		if (!bh) {
+			EXT4_ERROR_INODE(inode, "bad symlink.");
+			return ERR_PTR(-EFSCORRUPTED);
+		}
+	}
+
+	set_delayed_call(callback, ext4_free_link, bh);
+	nd_terminate_link(bh->b_data, inode->i_size,
+			  inode->i_sb->s_blocksize - 1);
+	return bh->b_data;
+}
+
 const struct inode_operations ext4_encrypted_symlink_inode_operations = {
 	.get_link	= ext4_encrypted_get_link,
 	.setattr	= ext4_setattr,
@@ -70,7 +105,7 @@ const struct inode_operations ext4_encrypted_symlink_inode_operations = {
 };
 
 const struct inode_operations ext4_symlink_inode_operations = {
-	.get_link	= page_get_link,
+	.get_link	= ext4_get_link,
 	.setattr	= ext4_setattr,
 	.getattr	= ext4_getattr,
 	.listxattr	= ext4_listxattr,