MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/4324
JIRA: https://issues.redhat.com/browse/RHEL-33888
This MR back ports idmapping changes to sync. our RHEL-9 kernel with the
upstream kernel to version 6.3.
Our current kernel has idmapped mounts support but there have been many
changes since this initial implementation in the base kernel. In
particular we need the type safety changes and we have seen difficulty
back porting other requested changes on more than one occassion.
The Jira this MR has been raised for is arother example of such a request.
It is needed for a back port of a BPF feature to RHEL 9 which allows BPF
programs to do file verification with LSM and fsverity. To satisfy this
request changes made in the upstream 6.3 kernel are needed which is the
reason we have chosen upstream 6.3 as the target release for the MR.
The first fix has been omitted because it appears to be the same as
24b5308cf5ee ("selftests/filesystems: grant executable permission to
run_fat_tests.sh"). In any case the requirement is to make the path
tools/testing/selftests/filesystems/fat/run_fat_tests.sh executable which
is done.
The second and third Omitted patches are a straight apply and revert leaving
the source unchanged.
Omitted-Fix: 1d4beeb4edc7 ("selftests/filesystems: grant executable permission to run_fat_tests.sh")
Omitted-Fix: 4a47c6385bb4 ovl: turn of SB_POSIXACL with idmapped layers temporarily
Omitted-Fix: 7c4d37c269ac Revert "ovl: turn of SB_POSIXACL with idmapped layers temporarily"
Signed-off-by: Ian Kent <ikent@redhat.com>
Approved-by: Scott Mayhew <smayhew@redhat.com>
Approved-by: Chris von Recklinghausen <crecklin@redhat.com>
Approved-by: Xin Long <lxin@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>
Merged-by: Rado Vrbovsky <rvrbovsk@redhat.com>
MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/5252
JIRA: https://issues.redhat.com/browse/RHEL-27743
JIRA: https://issues.redhat.com/browse/RHEL-59459
CVE: CVE-2024-46787
Depends: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/4961
This MR brings RHEL9 core MM code up to upstream's v6.6 LTS level.
This work follows up on the previous v6.5 update (RHEL-27742) and as such,
the bulk of this changeset is comprised of refactoring and clean-ups of
the internal implementation of several APIs as it further advances the
conversion to FOLIOS, and follow up on the per-VMA locking changes.
Also, with the rebase to v6.6 LTS, we complete the infrastructure to allow
Control-flow Enforcement Technology, a.k.a. Shadow Stacks, for x86 builds,
and we add a potential extra level of protection (assessment pending) to help
on mitigating kernel heap exploits dubbed as "SlubStick".
Follow-up fixes are omitted from this series either because they are irrelevant to
the bits we support on RHEL or because they depend on bigger changesets introduced
upstream more recently. A follow-up ticket (RHEL-27745) will deal with these and other cases separately.
Omitted-fix: e540b8c5da04 ("mips: mm: add slab availability checking in ioremap_prot")
Omitted-fix: f7875966dc0c ("tools headers UAPI: Sync files changed by new fchmodat2 and map_shadow_stack syscalls with the kernel sources")
Omitted-fix: df39038cd895 ("s390/mm: Fix VM_FAULT_HWPOISON handling in do_exception()")
Omitted-fix: 12bbaae7635a ("mm: create FOLIO_FLAG_FALSE and FOLIO_TYPE_OPS macros")
Omitted-fix: fd1a745ce03e ("mm: support page_mapcount() on page_has_type() pages")
Omitted-fix: d99e3140a4d3 ("mm: turn folio_test_hugetlb into a PageType")
Omitted-fix: fa2690af573d ("mm: page_ref: remove folio_try_get_rcu()")
Omitted-fix: f442fa614137 ("mm: gup: stop abusing try_grab_folio")
Omitted-fix: cb0f01beb166 ("mm/mprotect: fix dax pud handling")
Signed-off-by: Rafael Aquini <raquini@redhat.com>
Approved-by: John W. Linville <linville@redhat.com>
Approved-by: Mark Salter <msalter@redhat.com>
Approved-by: Marcelo Ricardo Leitner <mleitner@redhat.com>
Approved-by: Chris von Recklinghausen <crecklin@redhat.com>
Approved-by: Steve Best <sbest@redhat.com>
Approved-by: David Airlie <airlied@redhat.com>
Approved-by: Michal Schmidt <mschmidt@redhat.com>
Approved-by: Baoquan He <5820488-baoquan_he@users.noreply.gitlab.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>
Merged-by: Rado Vrbovsky <rvrbovsk@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-33888
Status: Linus
Conflicts: The cifs source has been moved in CentOS Stream so manually
apply rejected hunk to fs/smb/client/xattr.c.
Dropped hunks for ntfs3 because the source is not present in
the CentOS Stream source tree.
CentOS Stream commit 98ba731fc7 ("ovl: Move xattr support
to new xattrs.c file") moved ovl_own_xattr_set(), manually apply
changes.
CentOS Stream commit 67e2fcb2f3 ("evm: don't copy up
'security.evm' xattr") is present causing hunk #1 against
include/linux/evm.h to be rejected, manually apply.
Upstream commit 5d1ef2ce13a90 ("ima: Introduce
ima_get_current_hash_algo()") is not present in CentOS Stream
which causes fuzz 1 for hunk #1 against include/linux/ima.h.
There's a reject of hunk #1 for include/linux/lsm_hooks.h but
I can't see any reason for it, manually applied the hunk.
CentOS Stream does not have upstream commit ce5bb5a86e5eb
("ima: Return int in the functions to measure a buffer") which
results in a reject of hunk #2 against security/integrity/ima/ima.h
and hunks #8 and #11 against security/integrity/ima/ima_main.c, so
manually apply hunks. There also appears to be a whitespace
mismatch causing hunk #7 to report fuzz 2 on application.
CentOS Stream does not have upstream commit c7423dbdbc9ec
("ima: Handle -ESTALE returned by ima_filter_rule_match()")
which results in a reject of hunk #3 against
security/integrity/ima/ima_policy.c, so manually apply hunk.
commit 39f60c1ccee72caa0104145b5dbf5d37cce1ea39
Author: Christian Brauner <brauner@kernel.org>
Date: Fri Jan 13 12:49:23 2023 +0100
fs: port xattr to mnt_idmap
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Ian Kent <ikent@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-33888
Status: Linus
Conflicts: For consistency drop btrfs hunks because it isn't supported in
CentOS Stream and other backports also drop such hunks.
CentOS Stream commit 48fa94aacd ("ceph: fscrypt_auth handling
for ceph") is presnt which causes fuzz 2 in hunk #1 in
fs/ceph/super.h.
Upstream commit 427505ffeaa46 ("exportfs: use pr_debug for
unreachable debug statements") is not present causing fuzz 2
in hunk #1 against fs/exportfs/expfs.c.
Dropped hunks for ksmbd because the source is not present in the
CentOS Stream source tree.
Upstream commit 03fa86e9f79d8 ("namei: stash the sampled ->d_seq
into nameidata") is not present causing a fuzz 1 for hunk #14
against fs/namei.c.
CentOS Stream c4f3dd0731 ("nfsd: handle failure to collect
pre/post-op attrs more sanely") is present and causes a rejects
for hunks #4 and #5 against fs/nfsd/vfs.c, apply manually.
Dropped hunks for ntfs3 because the source is not present in the
CentOS Stream source tree.
CentOS Stream commit 98ba731fc7 ("ovl: Move xattr support to
new xattrs.c file") moves ovl_xattr_set() and ovl_xattr_get()
from fs/overlayfs/inode.c to fs/overlayfs/xattrs.c which causes
hunks #4 and #5 to fail, manually apply to fs/overlayfs/xattrs.c.
CentOS Stream commit 55177e4b83 ("ovl: mark xwhiteouts directory
with overlay.opaque='x'") and commit d17b324bb6 ("ovl: use
ovl_numlower() and ovl_lowerstack() accessors") change the first
and third hunks of fs/overlayfs/namei.c causing them to fail,
manually apply.
CentOS Stream commit 98ba731fc7 ("ovl: Move xattr support to
new xattrs.c file") causes fuzz 2 in hunk #5 of
fs/overlayfs/overlayfs.h
CentOS Stream commit 355a9c490a ("ovl: Add an alternative
type of whiteout") changes ovl_cache_update_ino() to
ovl_cache_update() in fs/overlayfs/readdir.c, make the change
manually.
Upstream commit 217af7e2f4deb ("apparmor: refactor profile
rules and attachments") is not in CentOS Stream causing hunk #1
to fail to apply so manually apply the change.
commit 4609e1f18e19c3b302e1eb4858334bca1532f780
Author: Christian Brauner <brauner@kernel.org>
Date: Fri Jan 13 12:49:22 2023 +0100
fs: port ->permission() to pass mnt_idmap
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Ian Kent <ikent@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-33888
Status: Linus
Conflicts: CentOS Stream has commit 3e0b6f1fa9 ("afs: use
read_seqbegin() in afs_check_validity() and afs_getattr()"),
manually apply hunk #2 to fs/afs/inode.c.
CentOS Stream commit 3b06927229 {"afs: split
afs_pagecache_valid() out of afs_validate()") is present which
causes a reject in fs/afs/internal.h, manually apply hunk to
fs/afs/internal.h.
For consistency drop btrfs hunks because it isn't supported in
CentOS Stream and other backports also drop such hunks.
CentOS Stream commit 48fa94aacd ("ceph: fscrypt_auth handling
for ceph") alters the definition of _ceph_setattr() causing fuzz.
The cifs source has been moved in CentOS Stream so manually
apply rejected hunks to fs/smb/client/cifsfs.h and
fs/smb/client/inode.c.
Upstream commit 2e1d66379e ("staging: erofs: drop the extern
prefix for function definitions") caused strange behaviour when
applying this patch, there was a conflict in fs/erofs/internal.h but
after a refresh the hunk and context looked ok. The hunk had to be
manually applied.
Upstream commit 2db0487faa211 ("f2fs: move f2fs_force_buffered_io()
into file.c") is not present in CentOS Stream which causes fuzz
when applying the first hunk to fs/f2fs/file.c.
Upstream commit 30abce053f811 ("fat: report creation time in statx")
is not present in CentOS Stream which caused a reject so apply change
manually.
Dropped hunks for ksmbd because the source is not present in the
CentOS Stream source tree.
Dropped hunks for ntfs3 because the source is not present in the
CentOS Stream source tree.
There was fuzz with hunk #2 against fs/nfs/inode.c but I was
unable to see any difference.
CentOS Stream commit 98ba731fc7 ("ovl: Move xattr support
to new xattrs.c file") is present which caused fuzz in
fs/overlayfs/overlayfs.h.
Upstream commit d919a1e79bac8 ("proc: fix a dentry lock race
between release_task and lookup") is not present in CentOS
Stream causing fuzz applying hunk #1 against fs/proc/base.c.
CentOS Stream commit 20c470188c ("vfs: plumb i_version
handling into struct kstat") is present causing fuzz in hunk
#2 against fs/stat.c.
Upstream commit e0c49bd2b4d3c ("fs: sysv: Fix sysv_nblocks()
returns wrong value") is not present in CentOS Stream causing
fuzz applying hunk#1 against fs/sysv/itree.c.
CentOS Stream commit 892da692fa ("shmem: support idmapped
mounts for tmpfs") is present so it's ok to pass idmap to
generic_fillattr().
CentOS Stream commit f0f830cd7e {"ceph: create symlinks
with encrypted and base64-encoded targets") uses the old
struct user_namespace and so leaves those changes out, make
those getattr() changes here.
Allow for CentOS Stream commit 6c3396a0d8 ("kernfs: Introduce
separate rwsem to protect inode attributes") which is already
present.
CentOS Stream commit f5219db0c0 ("KVM: fix Add KVM_CREATE_GUEST_MEMFD
ioctl() for guest-specific backing memory") updated the upstream commit
a7800aa80ea4d ("KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific
backing memory") to account for missing idmapping commits. Now we have
updated the second and final place these changes were made make the final
needed adjustment to match the original upstream patch.
commit b74d24f7a74ffd2d42ca883d84b7422b8d545901
Author: Christian Brauner <brauner@kernel.org>
Date: Fri Jan 13 12:49:12 2023 +0100
fs: port ->getattr() to pass mnt_idmap
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Ian Kent <ikent@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-33888
Status: Linus
Conflicts: CentOS Stream commit 3c29fadfb1 ("afs: split
afs_pagecache_valid() out of afs_validate()") is present, manually
adjust hunk #1 of fs/afs/internal.h.
For consistency drop btrfs hunks because it isn't supported in
CentOS Stream and other backports also drop such hunks.
CentOS Stream commit 48fa94aacd ("ceph: fscrypt_auth handling
for ceph") alters the definition of _ceph_setattr(), adjust
manually.
CentOS Stream commit 34b2a2b5a3 {"ceph: add some fscrypt
guardrails") introduces a call to fscrypt_prepare_setattr() which
causes fuzz when applying.
The cifs source has been moved in CentOS Stream so manually
apply rejected hunks to fs/smb/client/cifsfs.h and
fs/smb/client/inode.c.
Upstream commit 5a646fb3a3e2d ("coda: avoid doing bad things on
inode type changes during revalidation") is not present which
causes fuzz in fs/coda/coda_linux.h.
Dropped hunks for ntfs3 because the source is not present in
the CentOS Stream source tree.
CentOS Stream commit 98ba731fc7 ("ovl: Move xattr support
to new xattrs.c file") is presnt so manually apply hunk.
CentOS Stream commit 892da692fa ("shmem: support idmapped
mounts for tmpfs") is present so it's ok to pass idmap to
setattr_prepare() and setattr_copy().
Update to add incremental changes needed due to CentOS Stream
commit 469e1d13f6 ("shmem: quota support").
Allow for CentOS Stream commit 6c3396a0d8 ("kernfs: Introduce
separate rwsem to protect inode attributes") which is already
present.
CentOS Stream commit f5219db0c0 ("KVM: fix Add KVM_CREATE_GUEST_MEMFD
ioctl() for guest-specific backing memory") updated the upstream commit
a7800aa80ea4d ("KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific
backing memory") to account for missing idmapping commits. Now we have
updated one of the two places these changes were made make one of the
needed adjustments to match the original upstream patch.
commit c1632a0f11209338fc300c66252bcc4686e609e8
Author: Christian Brauner <brauner@kernel.org>
Date: Fri Jan 13 12:49:11 2023 +0100
fs: port ->setattr() to pass mnt_idmap
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Ian Kent <ikent@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-27743
Conflicts:
* mm/shmem.c: this commit had a merge conflict upstream with commit
6528733416f1 ("shmem: convert to ctime accessor functions"), backported
earlier in this set. The conflict was solved via merge commit ecd7db20474c
("Merge tag 'v6.6-vfs.tmpfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs"),
from which we borrow the hunk adjustment for this backport.
This patch is a backport of the following upstream commit:
commit 5de75970c9fd7220e394b76e6d20fbafa1369b5a
Author: Hugh Dickins <hughd@google.com>
Date: Tue Aug 8 21:30:59 2023 -0700
xattr: simple_xattr_set() return old_xattr to be freed
tmpfs wants to support limited user extended attributes, but kernfs
(or cgroupfs, the only kernfs with KERNFS_ROOT_SUPPORT_USER_XATTR)
already supports user extended attributes through simple xattrs: but
limited by a policy (128KiB per inode) too liberal to be used on tmpfs.
To allow a different limiting policy for tmpfs, without affecting the
policy for kernfs, change simple_xattr_set() to return the replaced or
removed xattr (if any), leaving the caller to update their accounting
then free the xattr (by simple_xattr_free(), renamed from the static
free_simple_xattr()).
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Message-Id: <158c6585-2aa7-d4aa-90ff-f7c3f8fe407c@google.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Rafael Aquini <raquini@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-56023
commit 24b3e3dd9c9c742a4dd18e71b6963f9e7ab72911
Author: Randy Dunlap <rdunlap@infradead.org>
Date: Fri, 11 Nov 2022 19:14:56 -0800
kernfs: fix all kernel-doc warnings and multiple typos
Fix kernel-doc warnings. Many of these are about a function's
return value, so use the kernel-doc Return: format to fix those
Use % prefix on numeric constant values.
dir.c: fix typos/spellos
file.c fix typo: s/taret/target/
Fix all of these kernel-doc warnings:
dir.c:305: warning: missing initial short description on line:
* kernfs_name_hash
dir.c:137: warning: No description found for return value of 'kernfs_path_from_node_locked'
dir.c:196: warning: No description found for return value of 'kernfs_name'
dir.c:224: warning: No description found for return value of 'kernfs_path_from_node'
dir.c:292: warning: No description found for return value of 'kernfs_get_parent'
dir.c:312: warning: No description found for return value of 'kernfs_name_hash'
dir.c:404: warning: No description found for return value of 'kernfs_unlink_sibling'
dir.c:588: warning: No description found for return value of 'kernfs_node_from_dentry'
dir.c:806: warning: No description found for return value of 'kernfs_find_ns'
dir.c:879: warning: No description found for return value of 'kernfs_find_and_get_ns'
dir.c:904: warning: No description found for return value of 'kernfs_walk_and_get_ns'
dir.c:927: warning: No description found for return value of 'kernfs_create_root'
dir.c:996: warning: No description found for return value of 'kernfs_root_to_node'
dir.c:1016: warning: No description found for return value of 'kernfs_create_dir_ns'
dir.c:1048: warning: No description found for return value of 'kernfs_create_empty_dir'
dir.c:1306: warning: No description found for return value of 'kernfs_next_descendant_post'
dir.c:1568: warning: No description found for return value of 'kernfs_remove_self'
dir.c:1630: warning: No description found for return value of 'kernfs_remove_by_name_ns'
dir.c:1667: warning: No description found for return value of 'kernfs_rename_ns'
file.c:66: warning: No description found for return value of 'of_on'
file.c:88: warning: No description found for return value of 'kernfs_deref_open_node_locked'
file.c:1036: warning: No description found for return value of '__kernfs_create_file'
inode.c💯 warning: No description found for return value of 'kernfs_setattr'
mount.c:160: warning: No description found for return value of 'kernfs_root_from_sb'
mount.c:198: warning: No description found for return value of 'kernfs_node_dentry'
mount.c:302: warning: No description found for return value of 'kernfs_super_ns'
mount.c:318: warning: No description found for return value of 'kernfs_get_tree'
symlink.c:28: warning: No description found for return value of 'kernfs_create_link'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20221112031456.22980-1-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Waiman Long <longman@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-52956
Upstream status: Linus
Conflicts: There's a reject of hunks 2, 4 and 5 against fs/kernfs/inode.c
because idmapping updates have not yet been made to the RHEL9
kernel.
The RH_KABI_EXTEND() macro is used to add the new lock to the
kernfs_root structure. This should be fine because CentOS Stream
commit 25d13c0bf2 ("kernfs: move struct kernfs_root out of
the public view") has already been included in RHEL-9 making the
kernfs_root structure private to kernfs.
commit 9caf696142252a466fb89e629d0eddcdced027b0
Author: Imran Khan <imran.f.khan@oracle.com>
Date: Thu Mar 9 22:09:30 2023 +1100
kernfs: Introduce separate rwsem to protect inode attributes.
Right now a global per-fs rwsem (kernfs_rwsem) synchronizes multiple
kernfs operations. On a large system with few hundred CPUs and few
hundred applications simultaneoulsy trying to access sysfs, this
results in multiple sys_open(s) contending on kernfs_rwsem via
kernfs_iop_permission and kernfs_dop_revalidate.
For example on a system with 384 cores, if I run 200 instances of an
application which is mostly executing the following loop:
for (int loop = 0; loop <100 ; loop++)
{
for (int port_num = 1; port_num < 2; port_num++)
{
for (int gid_index = 0; gid_index < 254; gid_index++ )
{
char ret_buf[64], ret_buf_lo[64];
char gid_file_path[1024];
int ret_len;
int ret_fd;
ssize_t ret_rd;
ub4 i, saved_errno;
memset(ret_buf, 0, sizeof(ret_buf));
memset(gid_file_path, 0, sizeof(gid_file_path));
ret_len = snprintf(gid_file_path, sizeof(gid_file_path),
"/sys/class/infiniband/%s/ports/%d/gids/%d",
dev_name,
port_num,
gid_index);
ret_fd = open(gid_file_path, O_RDONLY | O_CLOEXEC);
if (ret_fd < 0)
{
printf("Failed to open %s\n", gid_file_path);
continue;
}
/* Read the GID */
ret_rd = read(ret_fd, ret_buf, 40);
if (ret_rd == -1)
{
printf("Failed to read from file %s, errno: %u\n",
gid_file_path, saved_errno);
continue;
}
close(ret_fd);
}
}
I see contention around kernfs_rwsem as follows:
path_openat
|
|----link_path_walk.part.0.constprop.0
| |
| |--49.92%--inode_permission
| | |
| | --48.69%--kernfs_iop_permission
| | |
| | |--18.16%--down_read
| | |
| | |--15.38%--up_read
| | |
| | --14.58%--_raw_spin_lock
| | |
| | -----
| |
| |--29.08%--walk_component
| | |
| | --29.02%--lookup_fast
| | |
| | |--24.26%--kernfs_dop_revalidate
| | | |
| | | |--14.97%--down_read
| | | |
| | | --9.01%--up_read
| | |
| | --4.74%--__d_lookup
| | |
| | --4.64%--_raw_spin_lock
| | |
| | ----
Having a separate per-fs rwsem to protect kernfs inode attributes,
will avoid the above mentioned contention and result in better
performance as can bee seen below:
path_openat
|
|----link_path_walk.part.0.constprop.0
| |
| |
| |--27.06%--inode_permission
| | |
| | --25.84%--kernfs_iop_permission
| | |
| | |--9.29%--up_read
| | |
| | |--8.19%--down_read
| | |
| | --7.89%--_raw_spin_lock
| | |
| | ----
| |
| |--22.42%--walk_component
| | |
| | --22.36%--lookup_fast
| | |
| | |--16.07%--__d_lookup
| | | |
| | | --16.01%--_raw_spin_lock
| | | |
| | | ----
| | |
| | --6.28%--kernfs_dop_revalidate
| | |
| | |--3.76%--down_read
| | |
| | --2.26%--up_read
As can be seen from the above data the overhead due to both
kerfs_iop_permission and kernfs_dop_revalidate have gone down and
this also reduces overall run time of the earlier mentioned loop.
Signed-off-by: Imran Khan <imran.f.khan@oracle.com>
Link: https://lore.kernel.org/r/20230309110932.2889010-2-imran.f.khan@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian Kent <ikent@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2186094
Upstream status: Linus
commit aa1d058d48f292aa138e33ad12b7b4d18b5407cd
Author: Ian Kent <raven@themaw.net>
Date: Tue Oct 18 10:32:42 2022 +0800
kernfs: dont take i_lock on inode attr read
The kernfs write lock is held when the kernfs node inode attributes
are updated. Therefore, when either kernfs_iop_getattr() or
kernfs_iop_permission() are called the kernfs node inode attributes
won't change.
Consequently concurrent kernfs_refresh_inode() calls always copy the
same values from the kernfs node.
So there's no need to take the inode i_lock to get consistent values
for generic_fillattr() and generic_permission(), the kernfs read lock
is sufficient.
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Ian Kent <raven@themaw.net>
Link: https://lore.kernel.org/r/166606036215.13363.1288735296954908554.stgit@donald.themaw.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian Kent <ikent@redhat.com>
Bugzilla: http://bugzilla.redhat.com/2152737
Upstream status: master tree.
commit 393c3714081a53795bbff0e985d24146def6f57f
Author: Minchan Kim <minchan@kernel.org>
Date: Thu Nov 18 15:00:08 2021 -0800
kernfs: switch global kernfs_rwsem lock to per-fs lock
The kernfs implementation has big lock granularity(kernfs_rwsem) so
every kernfs-based(e.g., sysfs, cgroup) fs are able to compete the
lock. It makes trouble for some cases to wait the global lock
for a long time even though they are totally independent contexts
each other.
A general example is process A goes under direct reclaim with holding
the lock when it accessed the file in sysfs and process B is waiting
the lock with exclusive mode and then process C is waiting the lock
until process B could finish the job after it gets the lock from
process A.
This patch switches the global kernfs_rwsem to per-fs lock, which
put the rwsem into kernfs_root.
Suggested-by: Tejun Heo <tj@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Link: https://lore.kernel.org/r/20211118230008.2679780-1-minchan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2004858
Upstream status: Linus
Testing: The series has been included in RHEL-8 and customer
testing has been done there. The upstreaming process
includes fairly broad general testing as well.
commit 47b5c64d0ab5e7136db2b78c6ec710e0d8a5a36b
From: Ian Kent <raven@themaw.net>
Date: 2021-07-16 17:28:34 +0800
kernfs: use i_lock to protect concurrent inode updates
The inode operations .permission() and .getattr() use the kernfs node
write lock but all that's needed is the read lock to protect against
partial updates of these kernfs node fields which are all done under
the write lock.
And .permission() is called frequently during path walks and can cause
quite a bit of contention between kernfs node operations and path
walks when the number of concurrent walks is high.
To change kernfs_iop_getattr() and kernfs_iop_permission() to take
the rw sem read lock instead of the write lock an additional lock is
needed to protect against multiple processes concurrently updating
the inode attributes and link count in kernfs_refresh_inode().
The inode i_lock seems like the sensible thing to use to protect these
inode attribute updates so use it in kernfs_refresh_inode().
The last hunk in the patch, applied to kernfs_fill_super(), is possibly
not needed but taking the lock was present originally. I prefer to
continue to take it to protect against a partial update of the source
kernfs fields during the call to kernfs_refresh_inode() made by
kernfs_get_inode().
Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Ian Kent <raven@themaw.net>
Link: https://lore.kernel.org/r/162642771474.63632.16295959115893904470.stgit@web.messagingengine.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian Kent <ikent@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2004858
Upstream status: Linus
Testing: The series has been included in RHEL-8 and customer
testing has been done there. The upstreaming process
includes fairly broad general testing as well.
commit 7ba0273b2f34a55efe967d3c7381fb1da2ca195f
From: Ian Kent <raven@themaw.net>
Date: 2021-07-16 17:28:29 +0800
kernfs: switch kernfs to use an rwsem
The kernfs global lock restricts the ability to perform kernfs node
lookup operations in parallel during path walks.
Change the kernfs mutex to an rwsem so that, when opportunity arises,
node searches can be done in parallel with path walk lookups.
Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Ian Kent <raven@themaw.net>
Link: https://lore.kernel.org/r/162642770946.63632.2218304587223241374.stgit@web.messagingengine.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian Kent <ikent@redhat.com>
Move the ramfs aops to libfs and reuse them for kernfs and configfs.
Thosw two did not wire up ->set_page_dirty before and now get
__set_page_dirty_no_writeback, which is the right one for no-writeback
address_space usage.
Drop the now unused exports of the libfs helpers only used for ramfs-style
pagecache usage.
Link: https://lkml.kernel.org/r/20210614061512.3966143-3-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.
As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.
Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
The generic_fillattr() helper fills in the basic attributes associated
with an inode. Enable it to handle idmapped mounts. If the inode is
accessed through an idmapped mount map it into the mount's user
namespace before we store the uid and gid. If the initial user namespace
is passed nothing changes so non-idmapped mounts will see identical
behavior as before.
Link: https://lore.kernel.org/r/20210121131959.646623-12-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
The posix acl permission checking helpers determine whether a caller is
privileged over an inode according to the acls associated with the
inode. Add helpers that make it possible to handle acls on idmapped
mounts.
The vfs and the filesystems targeted by this first iteration make use of
posix_acl_fix_xattr_from_user() and posix_acl_fix_xattr_to_user() to
translate basic posix access and default permissions such as the
ACL_USER and ACL_GROUP type according to the initial user namespace (or
the superblock's user namespace) to and from the caller's current user
namespace. Adapt these two helpers to handle idmapped mounts whereby we
either map from or into the mount's user namespace depending on in which
direction we're translating.
Similarly, cap_convert_nscap() is used by the vfs to translate user
namespace and non-user namespace aware filesystem capabilities from the
superblock's user namespace to the caller's user namespace. Enable it to
handle idmapped mounts by accounting for the mount's user namespace.
In addition the fileystems targeted in the first iteration of this patch
series make use of the posix_acl_chmod() and, posix_acl_update_mode()
helpers. Both helpers perform permission checks on the target inode. Let
them handle idmapped mounts. These two helpers are called when posix
acls are set by the respective filesystems to handle this case we extend
the ->set() method to take an additional user namespace argument to pass
the mount's user namespace down.
Link: https://lore.kernel.org/r/20210121131959.646623-9-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.
Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.
Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
The two helpers inode_permission() and generic_permission() are used by
the vfs to perform basic permission checking by verifying that the
caller is privileged over an inode. In order to handle idmapped mounts
we extend the two helpers with an additional user namespace argument.
On idmapped mounts the two helpers will make sure to map the inode
according to the mount's user namespace and then peform identical
permission checks to inode_permission() and generic_permission(). If the
initial user namespace is passed nothing changes so non-idmapped mounts
will see identical behavior as before.
Link: https://lore.kernel.org/r/20210121131959.646623-6-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
User extended attributes are useful as metadata storage for kernfs
consumers like cgroups. Especially in the case of cgroups, it is useful
to have a central metadata store that multiple processes/services can
use to coordinate actions.
A concrete example is for userspace out of memory killers. We want to
let delegated cgroup subtree owners (running as non-root) to be able to
say "please avoid killing this cgroup". This is especially important for
desktop linux as delegated subtrees owners are less likely to run as
root.
This patch introduces a new flag, KERNFS_ROOT_SUPPORT_USER_XATTR, that
lets kernfs consumers enable user xattr support. An initial limit of 128
entries or 128KB -- whichever is hit first -- is placed per cgroup
because xattrs come from kernel memory and we don't want to let
unprivileged users accidentally eat up too much kernel memory.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Acked-by: Chris Down <chris@chrisdown.name>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
This helps set up size accounting in the next commit. Without this out
param, it's difficult to find out the removed xattr size without taking
a lock for longer and walking the xattr linked list twice.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Acked-by: Chris Down <chris@chrisdown.name>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
kernfs_node->id is currently a union kernfs_node_id which represents
either a 32bit (ino, gen) pair or u64 value. I can't see much value
in the usage of the union - all that's needed is a 64bit ID which the
current code is already limited to. Using a union makes the code
unnecessarily complicated and prevents using 64bit ino without adding
practical benefits.
This patch drops union kernfs_node_id and makes kernfs_node->id a u64.
ino is stored in the lower 32bits and gen upper. Accessors -
kernfs[_id]_ino() and kernfs[_id]_gen() - are added to retrieve the
ino and gen. This simplifies ID handling less cumbersome and will
allow using 64bit inos on supported archs.
This patch doesn't make any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexei Starovoitov <ast@kernel.org>
Based on 1 normalized pattern(s):
this file is released under the gplv2
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 68 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190114.292346262@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The implementation of kernfs_security_xattr_*() helpers reuses the
kernfs_node_xattr_*() functions, which take the suffix of the xattr name
and extract full xattr name from it using xattr_full_name(). However,
this function relies on the fact that the suffix passed to xattr
handlers from VFS is always constructed from the full name by just
incerementing the pointer. This doesn't necessarily hold for the callers
of kernfs_security_xattr_*(), so their usage will easily lead to
out-of-bounds access.
Fix this by moving the xattr name reconstruction to the VFS xattr
handlers and replacing the kernfs_security_xattr_*() helpers with more
general kernfs_xattr_*() helpers that take full xattr name and allow
accessing all kernfs node's xattrs.
Reported-by: kernel test robot <rong.a.chen@intel.com>
Fixes: b230d5aba2 ("LSM: add new hook for kernfs node initialization")
Fixes: ec882da5cd ("selinux: implement the kernfs_init_security hook")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This patch introduces a new security hook that is intended for
initializing the security data for newly created kernfs nodes, which
provide a way of storing a non-default security context, but need to
operate independently from mounts (and therefore may not have an
associated inode at the moment of creation).
The main motivation is to allow kernfs nodes to inherit the context of
the parent under SELinux, similar to the behavior of
security_inode_init_security(). Other LSMs may implement their own logic
for handling the creation of new nodes.
This patch also adds helper functions to <linux/kernfs.h> for
getting/setting security xattrs of a kernfs node so that LSMs hooks are
able to do their job. Other important attributes should be accessible
direcly in the kernfs_node fields (in case there is need for more, then
new helpers should be added to kernfs.h along with the patch that needs
them).
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: more manual merge fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Replace the special handling of security xattrs with simple_xattrs, as
is already done for the trusted xattrs. This simplifies the code and
allows LSMs to use more than just a single xattr to do their business.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: manual merge fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
This is a read-only operation, so we can simply return -ENODATA if
kn->iattr is NULL.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: minor merge fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Right now, kernfs_iattrs embeds the whole struct iattr, even though it
doesn't really use half of its fields... This both leads to wasting
space and makes the code look awkward. Let's just list the few fields
we need directly in struct kernfs_iattrs.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: merged a number of chunks manually due to fuzz]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Creating a new cache for kernfs_iattrs.
Currently, memory is allocated with kzalloc() which
always gives aligned memory. On ARM, this is 64 byte aligned.
To avoid the wastage of memory in aligning the size requested,
a new cache for kernfs_iattrs is created.
Size of struct kernfs_iattrs is 80 Bytes.
On ARM, it will come in kmalloc-128 slab.
and it will come in kmalloc-192 slab if debug info is enabled.
Extra bytes taken 48 bytes.
Total number of objects created : 4096
Total saving = 48*4096 = 192 KB
After creating new slab(When debug info is enabled) :
sh-3.2# cat /proc/slabinfo
...
kernfs_iattrs_cache 4069 4096 128 32 1 : tunables 0 0 0 : slabdata 128 128 0
...
All testing has been done on ARM target.
Signed-off-by: Ayush Mittal <ayush.m@samsung.com>
Signed-off-by: Vaneet Narang <v.narang@samsung.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This change allows creating kernfs files and directories with arbitrary
uid/gid instead of always using GLOBAL_ROOT_UID/GID by extending
kernfs_create_dir_ns() and kernfs_create_file_ns() with uid/gid arguments.
The "simple" kernfs_create_file() and kernfs_create_dir() are left alone
and always create objects belonging to the global root.
When creating symlinks ownership (uid/gid) is taken from the target kernfs
object.
Co-Developed-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
inode number and generation can identify a kernfs node. We are going to
export the identification by exportfs operations, so put ino and
generation into a separate structure. It's convenient when later patches
use the identification.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When working on adding exportfs operations in kernfs, I found it's hard
to initialize dentry->d_fsdata in the exportfs operations. Looks there
is no way to do it without race condition. Look at the kernfs code
closely, there is no point to set dentry->d_fsdata. inode->i_private
already points to kernfs_node, and we can get inode from a dentry. So
this patch just delete the d_fsdata usage.
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Set i_generation for kernfs inode. This is required to implement
exportfs operations. The generation is 32-bit, so it's possible the
generation wraps up and we find stale files. To reduce the posssibility,
we don't reuse inode numer immediately. When the inode number allocation
wraps, we increase generation number. In this way generation/inode
number consist of a 64-bit number which is unlikely duplicated. This
does make the idr tree more sparse and waste some memory. Since idr
manages 32-bit keys, idr uses a 6-level radix tree, each level covers 6
bits of the key. In a 100k inode kernfs, the worst case will have around
300k radix tree node. Each node is 576bytes, so the tree will use about
~150M memory. Sounds not too bad, if this really is a problem, we should
find better data structure.
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.
The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.
Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.
========
OVERVIEW
========
The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.
A number of requests were gathered for features to be included. The
following have been included:
(1) Make the fields a consistent size on all arches and make them large.
(2) Spare space, request flags and information flags are provided for
future expansion.
(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).
(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).
This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].
(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).
(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).
And the following have been left out for future extension:
(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].
Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.
(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).
(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].
(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].
(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).
(10) Extra coherency data may be useful in making backups [Andreas Dilger].
(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).
(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...
(This requires a separate system call - I have an fsinfo() call idea
for this).
(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].
(Deferred to fsinfo).
(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].
(Deferred to fsinfo).
(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).
(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).
(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].
(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).
(16) Femtosecond-resolution timestamps [Dave Chinner].
(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).
(17) A set multiple attributes syscall to go with this.
===============
NEW SYSTEM CALL
===============
The new system call is:
int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);
The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.
Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):
(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.
(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.
(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.
mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.
buffer points to the destination for the data. This must be 256 bytes in
size.
======================
MAIN ATTRIBUTES RECORD
======================
The following structures are defined in which to return the main attribute
set:
struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};
struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};
The defined bits in request_mask and stx_mask are:
STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]
stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.
Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.
The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:
STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs
Within the kernel, the supported flags are listed by:
KSTAT_ATTR_FS_IOC_FLAGS
[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]
New flags include:
STATX_ATTR_AUTOMOUNT Object is an automount trigger
These are for the use of GUI tools that might want to mark files specially,
depending on what they are.
Fields in struct statx come in a number of classes:
(0) stx_dev_*, stx_blksize.
These are local system information and are always available.
(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.
These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.
If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.
If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.
Note that there are instances where the type might not be valid, for
instance Windows reparse points.
(2) stx_rdev_*.
This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.
(3) stx_btime.
Similar to (1), except this will be set to 0 if it doesn't exist.
=======
TESTING
=======
The following test program can be used to test the statx system call:
samples/statx/test-statx.c
Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.
Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.
[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)
Secondly, the result of automounting on that directory.
[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This was spotted by the 'sparse' static checker.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull more vfs updates from Al Viro:
">rename2() work from Miklos + current_time() from Deepa"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: Replace current_fs_time() with current_time()
fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps
fs: Replace CURRENT_TIME with current_time() for inode timestamps
fs: proc: Delete inode time initializations in proc_alloc_inode()
vfs: Add current_time() api
vfs: add note about i_op->rename changes to porting
fs: rename "rename2" i_op to "rename"
vfs: remove unused i_op->rename
fs: make remaining filesystems use .rename2
libfs: support RENAME_NOREPLACE in simple_rename()
fs: support RENAME_NOREPLACE for local filesystems
ncpfs: fix unused variable warning
Pull vfs xattr updates from Al Viro:
"xattr stuff from Andreas
This completes the switch to xattr_handler ->get()/->set() from
->getxattr/->setxattr/->removexattr"
* 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
vfs: Remove {get,set,remove}xattr inode operations
xattr: Stop calling {get,set,remove}xattr inode operations
vfs: Check for the IOP_XATTR flag in listxattr
xattr: Add __vfs_{get,set,remove}xattr helpers
libfs: Use IOP_XATTR flag for empty directory handling
vfs: Use IOP_XATTR flag for bad-inode handling
vfs: Add IOP_XATTR inode operations flag
vfs: Move xattr_resolve_name to the front of fs/xattr.c
ecryptfs: Switch to generic xattr handlers
sockfs: Get rid of getxattr iop
sockfs: getxattr: Fail with -EOPNOTSUPP for invalid attribute names
kernfs: Switch to generic xattr handlers
hfs: Switch to generic xattr handlers
jffs2: Remove jffs2_{get,set,remove}xattr macros
xattr: Remove unnecessary NULL attribute name check
These inode operations are no longer used; remove them.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
current_fs_time() uses struct super_block* as an argument.
As per Linus's suggestion, this is changed to take struct
inode* as a parameter instead. This is because the function
is primarily meant for vfs inode timestamps.
Also the function was renamed as per Arnd's suggestion.
Change all calls to current_fs_time() to use the new
current_time() function instead. current_fs_time() will be
deleted.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
inode_change_ok() will be resposible for clearing capabilities and IMA
extended attributes and as such will need dentry. Give it as an argument
to inode_change_ok() instead of an inode. Also rename inode_change_ok()
to setattr_prepare() to better relect that it does also some
modifications in addition to checks.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
smack ->d_instantiate() uses ->setxattr(), so to be able to call it before
we'd hashed the new dentry and attached it to inode, we need ->setxattr()
instances getting the inode as an explicit argument rather than obtaining
it from dentry.
Similar change for ->getxattr() had been done in commit ce23e64. Unlike
->getxattr() (which is used by both selinux and smack instances of
->d_instantiate()) ->setxattr() is used only by smack one and unfortunately
it got missed back then.
Reported-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Tested-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Here's the "big" driver core update for 4.7-rc1.
Mostly just debugfs changes, the long-known and messy races with removing
debugfs files should be fixed thanks to the great work of Nicolai Stange. We
also have some isa updates in here (the x86 maintainers told me to take it
through this tree), a new warning when we run out of dynamic char major
numbers, and a few other assorted changes, details in the shortlog.
All have been in linux-next for some time with no reported issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
"Here's the "big" driver core update for 4.7-rc1.
Mostly just debugfs changes, the long-known and messy races with
removing debugfs files should be fixed thanks to the great work of
Nicolai Stange. We also have some isa updates in here (the x86
maintainers told me to take it through this tree), a new warning when
we run out of dynamic char major numbers, and a few other assorted
changes, details in the shortlog.
All have been in linux-next for some time with no reported issues"
* tag 'driver-core-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (32 commits)
Revert "base: dd: don't remove driver_data in -EPROBE_DEFER case"
gpio: ws16c48: Utilize the ISA bus driver
gpio: 104-idio-16: Utilize the ISA bus driver
gpio: 104-idi-48: Utilize the ISA bus driver
gpio: 104-dio-48e: Utilize the ISA bus driver
watchdog: ebc-c384_wdt: Utilize the ISA bus driver
iio: stx104: Utilize the module_isa_driver and max_num_isa_dev macros
iio: stx104: Add X86 dependency to STX104 Kconfig option
Documentation: Add ISA bus driver documentation
isa: Implement the max_num_isa_dev macro
isa: Implement the module_isa_driver macro
pnp: pnpbios: Add explicit X86_32 dependency to PNPBIOS
isa: Decouple X86_32 dependency from the ISA Kconfig option
driver-core: use 'dev' argument in dev_dbg_ratelimited stub
base: dd: don't remove driver_data in -EPROBE_DEFER case
kernfs: Move faulting copy_user operations outside of the mutex
devcoredump: add scatterlist support
debugfs: unproxify files created through debugfs_create_u32_array()
debugfs: unproxify files created through debugfs_create_blob()
debugfs: unproxify files created through debugfs_create_bool()
...
This is in preparation for the series that transitions
filesystem timestamps to use 64 bit time and hence make
them y2038 safe.
CURRENT_TIME macro will be deleted before merging the
aforementioned series.
Use current_fs_time() instead of CURRENT_TIME for inode
timestamps.
struct kernfs_node is associated with a sysfs file/ directory.
Truncate the values to appropriate time granularity when
writing to inode timestamps of the files.
ktime_get_real_ts() is used to obtain times for
struct kernfs_iattrs. Since these times are later assigned to
inode times using timespec_truncate() for all filesystem based
operations, we can save the supers list traversal time here by
using ktime_get_real_ts() directly.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a file on tmpfs has an ACL or a Default ACL, listxattr should include the
corresponding xattr name.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Use the VFS xattr handler infrastructure and get rid of similar code in
the filesystem. For implementing shmem_xattr_handler_set, we need a
version of simple_xattr_set which removes the attribute when value is
NULL. Use this to implement kernfs_iop_removexattr as well.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Rado Vrbovsky
Ian Kent
Rafael Aquini
Waiman Long
Luis Claudio R. Goncalves
Christoph Hellwig
Christian Brauner
Daniel Xu
Al Viro
Tejun Heo
Deepa Dinamani
Thomas Gleixner
Ondrej Mosnacek
Ayush Mittal
Dmitry Torokhov
Shaohua Li
David Howells
Bart Van Assche
Linus Torvalds
Andreas Gruenbacher
Jan Kara