This is a note to let you know that I've just added the patch titled
ext4: don't allow overlapping system zones
to the 4.9-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-don-t-allow-overlapping-system-zones.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Wed Mar 17 06:09:08 PM CET 2021
From: Jan Kara <jack@xxxxxxx>
Date: Wed, 17 Mar 2021 17:44:13 +0100
Subject: ext4: don't allow overlapping system zones
To: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>, Jan Kara <jack@xxxxxxx>, Lukas Czerner <lczerner@xxxxxxxxxx>, Theodore Ts'o <tytso@xxxxxxx>
Message-ID: <20210317164414.17364-3-jack@xxxxxxx>
From: Jan Kara <jack@xxxxxxx>
commit bf9a379d0980e7413d94cb18dac73db2bfc5f470 upstream.
Currently, add_system_zone() just silently merges two added system zones
that overlap. However the overlap should not happen and it generally
suggests that some unrelated metadata overlap which indicates the fs is
corrupted. We should have caught such problems earlier (e.g. in
ext4_check_descriptors()) but add this check as another line of defense.
In later patch we also use this for stricter checking of journal inode
extent tree.
Reviewed-by: Lukas Czerner <lczerner@xxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
Link: https://lore.kernel.org/r/20200728130437.7804-3-jack@xxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/block_validity.c | 34 ++++++++++++----------------------
1 file changed, 12 insertions(+), 22 deletions(-)
--- a/fs/ext4/block_validity.c
+++ b/fs/ext4/block_validity.c
@@ -57,7 +57,7 @@ static int add_system_zone(struct ext4_s
ext4_fsblk_t start_blk,
unsigned int count)
{
- struct ext4_system_zone *new_entry = NULL, *entry;
+ struct ext4_system_zone *new_entry, *entry;
struct rb_node **n = &sbi->system_blks.rb_node, *node;
struct rb_node *parent = NULL, *new_node = NULL;
@@ -68,30 +68,20 @@ static int add_system_zone(struct ext4_s
n = &(*n)->rb_left;
else if (start_blk >= (entry->start_blk + entry->count))
n = &(*n)->rb_right;
- else {
- if (start_blk + count > (entry->start_blk +
- entry->count))
- entry->count = (start_blk + count -
- entry->start_blk);
- new_node = *n;
- new_entry = rb_entry(new_node, struct ext4_system_zone,
- node);
- break;
- }
+ else /* Unexpected overlap of system zones. */
+ return -EFSCORRUPTED;
}
- if (!new_entry) {
- new_entry = kmem_cache_alloc(ext4_system_zone_cachep,
- GFP_KERNEL);
- if (!new_entry)
- return -ENOMEM;
- new_entry->start_blk = start_blk;
- new_entry->count = count;
- new_node = &new_entry->node;
+ new_entry = kmem_cache_alloc(ext4_system_zone_cachep,
+ GFP_KERNEL);
+ if (!new_entry)
+ return -ENOMEM;
+ new_entry->start_blk = start_blk;
+ new_entry->count = count;
+ new_node = &new_entry->node;
- rb_link_node(new_node, parent, n);
- rb_insert_color(new_node, &sbi->system_blks);
- }
+ rb_link_node(new_node, parent, n);
+ rb_insert_color(new_node, &sbi->system_blks);
/* Can we merge to the left? */
node = rb_prev(new_node);
Patches currently in stable-queue which might be from jack@xxxxxxx are
queue-4.9/ext4-handle-error-of-ext4_setup_system_zone-on-remount.patch
queue-4.9/ext4-check-journal-inode-extents-more-carefully.patch
queue-4.9/ext4-don-t-allow-overlapping-system-zones.patch
