Patch "ext4: support fast symlinks from ext3 file systems" has been added to the 4.14-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    ext4: support fast symlinks from ext3 file systems

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ext4-support-fast-symlinks-from-ext3-file-systems.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From fc82228a5e3860502dbf3bfa4a9570cb7093cf7f Mon Sep 17 00:00:00 2001
From: Andi Kleen <ak@linux.intel.com>
Date: Sun, 3 Dec 2017 20:38:01 -0500
Subject: ext4: support fast symlinks from ext3 file systems

From: Andi Kleen <ak@linux.intel.com>

commit fc82228a5e3860502dbf3bfa4a9570cb7093cf7f upstream.

407cd7fb83c0 (ext4: change fast symlink test to not rely on i_blocks)
broke ~10 years old ext3 file systems created by 2.6.17. Any ELF
executable fails because the /lib/ld-linux.so.2 fast symlink
cannot be read anymore.

The patch assumed fast symlinks were created in a specific way,
but that's not true on these really old file systems.

The new behavior is apparently needed only with the large EA inode
feature.

Revert to the old behavior if the large EA inode feature is not set.

This makes my old VM boot again.

Fixes: 407cd7fb83c0 (ext4: change fast symlink test to not rely on i_blocks)
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/ext4/inode.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -149,6 +149,15 @@ static int ext4_meta_trans_blocks(struct
  */
 int ext4_inode_is_fast_symlink(struct inode *inode)
 {
+	if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
+		int ea_blocks = EXT4_I(inode)->i_file_acl ?
+				EXT4_CLUSTER_SIZE(inode->i_sb) >> 9 : 0;
+
+		if (ext4_has_inline_data(inode))
+			return 0;
+
+		return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
+	}
 	return S_ISLNK(inode->i_mode) && inode->i_size &&
 	       (inode->i_size < EXT4_N_BLOCKS * 4);
 }


Patches currently in stable-queue which might be from ak@linux.intel.com are

queue-4.14/x86-boot-compressed-64-print-error-if-5-level-paging-is-not-supported.patch
queue-4.14/x86-boot-compressed-64-detect-and-handle-5-level-paging-at-boot-time.patch
queue-4.14/ext4-support-fast-symlinks-from-ext3-file-systems.patch