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Patch "btrfs: use proper endianness accessors for super_copy" has been added to the 4.15-stable tree

PATCH [email protected] 1 participant 1 message Mar 6, 2018

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

btrfs: use proper endianness accessors for super_copy

to the 4.15-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:
btrfs-use-proper-endianness-accessors-for-super_copy.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 3c181c12c431fe33b669410d663beb9cceefcd1b Mon Sep 17 00:00:00 2001

From: Anand Jain <[email protected]>
Date: Thu, 22 Feb 2018 21:58:42 +0800
Subject: btrfs: use proper endianness accessors for super_copy

From: Anand Jain <[email protected]>

commit 3c181c12c431fe33b669410d663beb9cceefcd1b upstream.

The fs_info::super_copy is a byte copy of the on-disk structure and all members must use the accessor macros/functions to obtain the right value. This was missing in update_super_roots and in sysfs readers.

Moving between opposite endianness hosts will report bogus numbers in sysfs, and mount may fail as the root will not be restored correctly. If the filesystem is always used on a same endian host, this will not be a problem.

Fix this by using the btrfs_set_super...() functions to set fs_info::super_copy values, and for the sysfs, use the cached fs_info::nodesize/sectorsize values.

CC [email protected]
Fixes df93589a17378 ("btrfs: export more from FS_INFO to sysfs")
Signed-off-by Anand Jain <[email protected]>
Reviewed-by Liu Bo <[email protected]>
Reviewed-by David Sterba <[email protected]>
[ update changelog ]
Signed-off-by David Sterba <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 fs/btrfs/sysfs.c       |    8 +++-----
 fs/btrfs/transaction.c |   20 ++++++++++++--------
 2 files changed, 15 insertions(+), 13 deletions(-)
fs/btrfs/sysfs.c +3 -5
@@ -423,7 +423,7 @@ static ssize_t btrfs_nodesize_show(struc
 {
 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 
-	return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
+	return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->nodesize);
 }
 
 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);

@@ -433,8 +433,7 @@ static ssize_t btrfs_sectorsize_show(str
 {
 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 
-	return snprintf(buf, PAGE_SIZE, "%u\n",
-			fs_info->super_copy->sectorsize);
+	return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->sectorsize);
 }
 
 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);

@@ -444,8 +443,7 @@ static ssize_t btrfs_clone_alignment_sho
 {
 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 
-	return snprintf(buf, PAGE_SIZE, "%u\n",
-			fs_info->super_copy->sectorsize);
+	return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->sectorsize);
 }
 
 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);
fs/btrfs/transaction.c +12 -8
@@ -1723,19 +1723,23 @@ static void update_super_roots(struct bt
 
 	super = fs_info->super_copy;
 
+	/* update latest btrfs_super_block::chunk_root refs */
 	root_item = &fs_info->chunk_root->root_item;
-	super->chunk_root = root_item->bytenr;
-	super->chunk_root_generation = root_item->generation;
-	super->chunk_root_level = root_item->level;
+	btrfs_set_super_chunk_root(super, root_item->bytenr);
+	btrfs_set_super_chunk_root_generation(super, root_item->generation);
+	btrfs_set_super_chunk_root_level(super, root_item->level);
 
+	/* update latest btrfs_super_block::root refs */
 	root_item = &fs_info->tree_root->root_item;
-	super->root = root_item->bytenr;
-	super->generation = root_item->generation;
-	super->root_level = root_item->level;
+	btrfs_set_super_root(super, root_item->bytenr);
+	btrfs_set_super_generation(super, root_item->generation);
+	btrfs_set_super_root_level(super, root_item->level);
+
 	if (btrfs_test_opt(fs_info, SPACE_CACHE))
-		super->cache_generation = root_item->generation;
+		btrfs_set_super_cache_generation(super, root_item->generation);
 	if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
-		super->uuid_tree_generation = root_item->generation;
+		btrfs_set_super_uuid_tree_generation(super,
+						     root_item->generation);
 }
 
 int btrfs_transaction_in_commit(struct btrfs_fs_info *info)

Patches currently in stable-queue which might be from [email protected] are

queue-4.15/btrfs-use-proper-endianness-accessors-for-super_copy.patch