This is a note to let you know that I've just added the patch titled btrfs: prop: fix vanished compression property after failed set to the 4.19-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-prop-fix-vanished-compression-property-after-failed-set.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 272e5326c7837697882ce3162029ba893059b616 Mon Sep 17 00:00:00 2001 From: Anand Jain <anand.jain@xxxxxxxxxx> Date: Tue, 2 Apr 2019 18:07:40 +0800 Subject: btrfs: prop: fix vanished compression property after failed set From: Anand Jain <anand.jain@xxxxxxxxxx> commit 272e5326c7837697882ce3162029ba893059b616 upstream. The compression property resets to NULL, instead of the old value if we fail to set the new compression parameter. $ btrfs prop get /btrfs compression compression=lzo $ btrfs prop set /btrfs compression zli ERROR: failed to set compression for /btrfs: Invalid argument $ btrfs prop get /btrfs compression This is because the compression property ->validate() is successful for 'zli' as the strncmp() used the length passed from the userspace. Fix it by using the expected string length in strncmp(). Fixes: 63541927c8d1 ("Btrfs: add support for inode properties") Fixes: 5c1aab1dd544 ("btrfs: Add zstd support") CC: stable@xxxxxxxxxxxxxxx # 4.14+ Reviewed-by: Nikolay Borisov <nborisov@xxxxxxxx> Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx> Reviewed-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/btrfs/props.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/fs/btrfs/props.c +++ b/fs/btrfs/props.c @@ -366,11 +366,11 @@ int btrfs_subvol_inherit_props(struct bt static int prop_compression_validate(const char *value, size_t len) { - if (!strncmp("lzo", value, len)) + if (!strncmp("lzo", value, 3)) return 0; - else if (!strncmp("zlib", value, len)) + else if (!strncmp("zlib", value, 4)) return 0; - else if (!strncmp("zstd", value, len)) + else if (!strncmp("zstd", value, 4)) return 0; return -EINVAL; Patches currently in stable-queue which might be from anand.jain@xxxxxxxxxx are queue-4.19/btrfs-prop-fix-vanished-compression-property-after-failed-set.patch queue-4.19/btrfs-prop-fix-zstd-compression-parameter-validation.patch