This is a note to let you know that I've just added the patch titled erofs: derive atime instead of leaving it empty to the 5.4-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: erofs-derive-atime-instead-of-leaving-it-empty.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From d3938ee23e97bfcac2e0eb6b356875da73d700df Mon Sep 17 00:00:00 2001 From: Gao Xiang <hsiangkao@xxxxxxxxxx> Date: Sun, 1 Nov 2020 03:51:02 +0800 Subject: erofs: derive atime instead of leaving it empty From: Gao Xiang <hsiangkao@xxxxxxxxxx> commit d3938ee23e97bfcac2e0eb6b356875da73d700df upstream. EROFS has _only one_ ondisk timestamp (ctime is currently documented and recorded, we might also record mtime instead with a new compat feature if needed) for each extended inode since EROFS isn't mainly for archival purposes so no need to keep all timestamps on disk especially for Android scenarios due to security concerns. Also, romfs/cramfs don't have their own on-disk timestamp, and squashfs only records mtime instead. Let's also derive access time from ondisk timestamp rather than leaving it empty, and if mtime/atime for each file are really needed for specific scenarios as well, we can also use xattrs to record them then. Link: https://lore.kernel.org/r/20201031195102.21221-1-hsiangkao@xxxxxxx [ Gao Xiang: It'd be better to backport for user-friendly concern. ] Fixes: 431339ba9042 ("staging: erofs: add inode operations") Cc: stable <stable@xxxxxxxxxxxxxxx> # 4.19+ Reported-by: nl6720 <nl6720@xxxxxxxxx> Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx> Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/erofs/inode.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) --- a/fs/erofs/inode.c +++ b/fs/erofs/inode.c @@ -107,11 +107,9 @@ static struct page *erofs_read_inode(str i_gid_write(inode, le32_to_cpu(die->i_gid)); set_nlink(inode, le32_to_cpu(die->i_nlink)); - /* ns timestamp */ - inode->i_mtime.tv_sec = inode->i_ctime.tv_sec = - le64_to_cpu(die->i_ctime); - inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = - le32_to_cpu(die->i_ctime_nsec); + /* extended inode has its own timestamp */ + inode->i_ctime.tv_sec = le64_to_cpu(die->i_ctime); + inode->i_ctime.tv_nsec = le32_to_cpu(die->i_ctime_nsec); inode->i_size = le64_to_cpu(die->i_size); @@ -149,11 +147,9 @@ static struct page *erofs_read_inode(str i_gid_write(inode, le16_to_cpu(dic->i_gid)); set_nlink(inode, le16_to_cpu(dic->i_nlink)); - /* use build time to derive all file time */ - inode->i_mtime.tv_sec = inode->i_ctime.tv_sec = - sbi->build_time; - inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = - sbi->build_time_nsec; + /* use build time for compact inodes */ + inode->i_ctime.tv_sec = sbi->build_time; + inode->i_ctime.tv_nsec = sbi->build_time_nsec; inode->i_size = le32_to_cpu(dic->i_size); if (erofs_inode_is_data_compressed(vi->datalayout)) @@ -167,6 +163,11 @@ static struct page *erofs_read_inode(str goto err_out; } + inode->i_mtime.tv_sec = inode->i_ctime.tv_sec; + inode->i_atime.tv_sec = inode->i_ctime.tv_sec; + inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec; + inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec; + if (!nblks) /* measure inode.i_blocks as generic filesystems */ inode->i_blocks = roundup(inode->i_size, EROFS_BLKSIZ) >> 9; Patches currently in stable-queue which might be from hsiangkao@xxxxxxxxxx are queue-5.4/erofs-derive-atime-instead-of-leaving-it-empty.patch