+ From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

+ From: Jon DeVree <nuxi@vault24.org>

+ Date: Sun, 11 Feb 2024 10:34:58 -0500

+ Subject: [PATCH] fs/xfs: Handle non-continuous data blocks in directory

+  extents

+ 

+ The directory extent list does not have to be a continuous list of data

+ blocks. When GRUB tries to read a non-existant member of the list,

+ grub_xfs_read_file() will return a block of zero'ed memory. Checking for

+ a zero'ed magic number is sufficient to skip this non-existant data block.

+ 

+ Prior to commit 07318ee7e (fs/xfs: Fix XFS directory extent parsing)

+ this was handled as a subtle side effect of reading the (non-existant)

+ tail data structure. Since the block was zero'ed the computation of the

+ number of directory entries in the block would return 0 as well.

+ 

+ Fixes: 07318ee7e (fs/xfs: Fix XFS directory extent parsing)

+ Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=2254370

+ 

+ Signed-off-by: Jon DeVree <nuxi@vault24.org>

+ Reviewed-By: Vladimir Serbinenko <phcoder@gmail.com>

+ Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

+ ---

+  grub-core/fs/xfs.c | 10 ++++++++++

+  1 file changed, 10 insertions(+)

+ 

+ diff --git a/grub-core/fs/xfs.c b/grub-core/fs/xfs.c

+ index bc2224dbb463..8e02ab4a3014 100644

+ --- a/grub-core/fs/xfs.c

+ +++ b/grub-core/fs/xfs.c

+ @@ -902,6 +902,7 @@ grub_xfs_iterate_dir (grub_fshelp_node_t dir,

+  					grub_xfs_first_de(dir->data, dirblock);

+  	    int entries = -1;

+  	    char *end = dirblock + dirblk_size;

+ +	    grub_uint32_t magic;

+  

+  	    numread = grub_xfs_read_file (dir, 0, 0,

+  					  blk << dirblk_log2,

+ @@ -912,6 +913,15 @@ grub_xfs_iterate_dir (grub_fshelp_node_t dir,

+  	        return 0;

+  	      }

+  

+ +	    /*

+ +	     * If this data block isn't actually part of the extent list then

+ +	     * grub_xfs_read_file() returns a block of zeros. So, if the magic

+ +	     * number field is all zeros then this block should be skipped.

+ +	     */

+ +	    magic = *(grub_uint32_t *)(void *) dirblock;

+ +	    if (!magic)

+ +	      continue;

+ +

+  	    /*

+  	     * Leaf and tail information are only in the data block if the number

+  	     * of extents is 1.

+ Patch0359: 0359-fs-xfs-Handle-non-continuous-data-blocks-in-director.patch

+ Release:	120%{?dist}

+ * Fri Apr 12 2024 Nicolas Frayer <nfrayer@redhat.com> - 2.06-120

+ - fs/xfs: Handle non-continuous data blocks in directory extents

+ - Related: #2254370

+