You really ought to cc the xfs list for questions about longstanding behaviors of XFS... [cc linux-xfs] --D On Fri, Mar 18, 2022 at 10:37:03AM +0000, xuyang2018.jy@xxxxxxxxxxx wrote: > Hi Darrick, Jack > > Petr meet a problem when running creat09 on xfs, ext4 doesn't have problem. > > It seems xfs will still use umask when enable default acl, but ext4 will > not. > > As umask2 manpage , it said > "Alternatively, if the parent directory has a default ACL (see acl(5)), > the umask is ignored, the default ACL is inherited, the permission bits > are set based on the inherited ACL, and permission bits absent > in the mode argument are turned off. > " > > It seem xfs doesn't obey this rule. > > the xfs calltrace as below: > > will use inode_init_owner(struct user_namespace *mnt_userns, > structinode *inode) > > 296.760675] xfs_init_new_inode+0x10e/0x6c0 > [ 296.760678] xfs_create+0x401/0x610 > will use posix_acl_create(dir, &mode, &default_acl, &acl); > [ 296.760681] xfs_generic_create+0x123/0x2e0 > [ 296.760684] ? _raw_spin_unlock+0x16/0x30 > [ 296.760687] path_openat+0xfb8/0x1210 > [ 296.760689] do_filp_open+0xb4/0x120 > [ 296.760691] ? file_tty_write.isra.31+0x203/0x340 > [ 296.760697] ? __check_object_size+0x150/0x170 > [ 296.760699] do_sys_openat2+0x242/0x310 > [ 296.760702] do_sys_open+0x4b/0x80 > [ 296.760704] do_syscall_64+0x3a/0x80 > > > the ext4 calltrace as below: > [ 296.460999] __ext4_new_inode+0xe07/0x1780 [ext4] > posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); > [ 296.461035] ext4_create+0x106/0x1c0 [ext4] > [ 296.461059] path_openat+0xfb8/0x1210 > [ 296.461062] do_filp_open+0xb4/0x120 > [ 296.461065] ? __check_object_size+0x150/0x170 > [ 296.461068] do_sys_openat2+0x242/0x310 > [ 296.461070] do_sys_open+0x4b/0x80 > [ 296.461073] do_syscall_64+0x3a/0x80 > [ 296.461077] entry_SYSCALL_64_after_hwframe+0x44/0xae > > I guess xfs modify its mode value instead of inode->i_mode in > posix_acl_create by using current->umask value, so inode_init_owner > doesn't clear no-sgid bits on created file because of missing S_IXGRP. > > Is it a kernel bug? > > Best Regards > Yang Xu > > > Hi Petr > > > > It fails because the create file without S_IXGRP mode, then we miss > > remove S_ISGID[1] bit. > > > > But I don't known why other filesystem doesn't have this problem. > > > > [1] > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/inode.c#n2249 > > > > Best Regards > > Yang Xu > >> XFS fails on umask 0077: > >> > >> tst_test.c:1528: TINFO: Testing on xfs > >> tst_test.c:997: TINFO: Formatting /dev/loop0 with xfs opts='' extra opts='' > >> tst_test.c:1458: TINFO: Timeout per run is 0h 05m 00s > >> creat09.c:61: TINFO: User nobody: uid = 65534, gid = 65534 > >> creat09.c:62: TINFO: Found unused GID 3: SUCCESS (0) > >> creat09.c:93: TPASS: mntpoint/testdir/creat.tmp: Owned by correct group > >> creat09.c:97: TFAIL: mntpoint/testdir/creat.tmp: Setgid bit is set > >> creat09.c:93: TPASS: mntpoint/testdir/open.tmp: Owned by correct group > >> creat09.c:97: TFAIL: mntpoint/testdir/open.tmp: Setgid bit is set > >> > >> Thus clear the default umask. > >> > >> Signed-off-by: Petr Vorel<pvorel@xxxxxxx> > >> --- > >> testcases/kernel/syscalls/creat/creat09.c | 2 ++ > >> 1 file changed, 2 insertions(+) > >> > >> diff --git a/testcases/kernel/syscalls/creat/creat09.c b/testcases/kernel/syscalls/creat/creat09.c > >> index bed7bddb0e..70da7d2fc7 100644 > >> --- a/testcases/kernel/syscalls/creat/creat09.c > >> +++ b/testcases/kernel/syscalls/creat/creat09.c > >> @@ -56,6 +56,8 @@ static void setup(void) > >> (int)ltpuser->pw_gid); > >> free_gid = tst_get_free_gid(ltpuser->pw_gid); > >> > >> + umask(0); > >> + > >> /* Create directories and set permissions */ > >> SAFE_MKDIR(WORKDIR, MODE_RWX); > >> SAFE_CHOWN(WORKDIR, ltpuser->pw_uid, free_gid); > >
