From: Chao Yu Date: Tue, 17 May 2022 03:37:23 +0000 (+0800) Subject: f2fs: fix fallocate to use file_modified to update permissions consistently X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=958ed92922028ec67f504dcdc72bfdfd0f43936a;p=linux.git f2fs: fix fallocate to use file_modified to update permissions consistently This patch tries to fix permission consistency issue as all other mainline filesystems. Since the initial introduction of (posix) fallocate back at the turn of the century, it has been possible to use this syscall to change the user-visible contents of files. This can happen by extending the file size during a preallocation, or through any of the newer modes (punch, zero, collapse, insert range). Because the call can be used to change file contents, we should treat it like we do any other modification to a file -- update the mtime, and drop set[ug]id privileges/capabilities. The VFS function file_modified() does all this for us if pass it a locked inode, so let's make fallocate drop permissions correctly. Cc: stable@kernel.org Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim --- diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 216081ea8c813..7aac53ac5acfb 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1780,6 +1780,10 @@ static long f2fs_fallocate(struct file *file, int mode, inode_lock(inode); + ret = file_modified(file); + if (ret) + goto out; + if (mode & FALLOC_FL_PUNCH_HOLE) { if (offset >= inode->i_size) goto out;