27 Aug, 2018
1 commit
-
Pull IDA updates from Matthew Wilcox:
"A better IDA API:id = ida_alloc(ida, GFP_xxx);
ida_free(ida, id);rather than the cumbersome ida_simple_get(), ida_simple_remove().
The new IDA API is similar to ida_simple_get() but better named. The
internal restructuring of the IDA code removes the bitmap
preallocation nonsense.I hope the net -200 lines of code is convincing"
* 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax: (29 commits)
ida: Change ida_get_new_above to return the id
ida: Remove old API
test_ida: check_ida_destroy and check_ida_alloc
test_ida: Convert check_ida_conv to new API
test_ida: Move ida_check_max
test_ida: Move ida_check_leaf
idr-test: Convert ida_check_nomem to new API
ida: Start new test_ida module
target/iscsi: Allocate session IDs from an IDA
iscsi target: fix session creation failure handling
drm/vmwgfx: Convert to new IDA API
dmaengine: Convert to new IDA API
ppc: Convert vas ID allocation to new IDA API
media: Convert entity ID allocation to new IDA API
ppc: Convert mmu context allocation to new IDA API
Convert net_namespace to new IDA API
cb710: Convert to new IDA API
rsxx: Convert to new IDA API
osd: Convert to new IDA API
sd: Convert to new IDA API
...
22 Aug, 2018
1 commit
-
The new API is much easier for this user. Also add kerneldoc for
get_anon_bdev().Signed-off-by: Matthew Wilcox
18 Aug, 2018
3 commits
-
We need to distinguish the situations when shrinker has very small
amount of objects (see vfs_pressure_ratio() called from
super_cache_count()), and when it has no objects at all. Currently, in
the both of these cases, shrinker::count_objects() returns 0.The patch introduces new SHRINK_EMPTY return value, which will be used
for "no objects at all" case. It's is a refactoring mostly, as
SHRINK_EMPTY is replaced by 0 by all callers of do_shrink_slab() in this
patch, and all the magic will happen in further.Link: http://lkml.kernel.org/r/153063069574.1818.11037751256699341813.stgit@localhost.localdomain
Signed-off-by: Kirill Tkhai
Acked-by: Vladimir Davydov
Tested-by: Shakeel Butt
Cc: Al Viro
Cc: Andrey Ryabinin
Cc: Chris Wilson
Cc: Greg Kroah-Hartman
Cc: Guenter Roeck
Cc: "Huang, Ying"
Cc: Johannes Weiner
Cc: Josef Bacik
Cc: Li RongQing
Cc: Matthew Wilcox
Cc: Matthias Kaehlcke
Cc: Mel Gorman
Cc: Michal Hocko
Cc: Minchan Kim
Cc: Philippe Ombredanne
Cc: Roman Gushchin
Cc: Sahitya Tummala
Cc: Stephen Rothwell
Cc: Tetsuo Handa
Cc: Thomas Gleixner
Cc: Waiman Long
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add list_lru::shrinker_id field and populate it by registered shrinker
id.This will be used to set correct bit in memcg shrinkers map by lru code
in next patches, after there appeared the first related to memcg element
in list_lru.Link: http://lkml.kernel.org/r/153063059758.1818.14866596416857717800.stgit@localhost.localdomain
Signed-off-by: Kirill Tkhai
Acked-by: Vladimir Davydov
Tested-by: Shakeel Butt
Cc: Al Viro
Cc: Andrey Ryabinin
Cc: Chris Wilson
Cc: Greg Kroah-Hartman
Cc: Guenter Roeck
Cc: "Huang, Ying"
Cc: Johannes Weiner
Cc: Josef Bacik
Cc: Li RongQing
Cc: Matthew Wilcox
Cc: Matthias Kaehlcke
Cc: Mel Gorman
Cc: Michal Hocko
Cc: Minchan Kim
Cc: Philippe Ombredanne
Cc: Roman Gushchin
Cc: Sahitya Tummala
Cc: Stephen Rothwell
Cc: Tetsuo Handa
Cc: Thomas Gleixner
Cc: Waiman Long
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Do two list_lru_init_memcg() calls after prealloc_super().
destroy_unused_super() in fail path is OK with this. Next patch needs
such the order.Link: http://lkml.kernel.org/r/153063058712.1818.3382490999719078571.stgit@localhost.localdomain
Signed-off-by: Kirill Tkhai
Acked-by: Vladimir Davydov
Tested-by: Shakeel Butt
Cc: Al Viro
Cc: Andrey Ryabinin
Cc: Chris Wilson
Cc: Greg Kroah-Hartman
Cc: Guenter Roeck
Cc: "Huang, Ying"
Cc: Johannes Weiner
Cc: Josef Bacik
Cc: Li RongQing
Cc: Matthew Wilcox
Cc: Matthias Kaehlcke
Cc: Mel Gorman
Cc: Michal Hocko
Cc: Minchan Kim
Cc: Philippe Ombredanne
Cc: Roman Gushchin
Cc: Sahitya Tummala
Cc: Stephen Rothwell
Cc: Tetsuo Handa
Cc: Thomas Gleixner
Cc: Waiman Long
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
05 Jun, 2018
1 commit
-
Pull misc vfs updates from Al Viro:
"Misc bits and pieces not fitting into anything more specific"* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
vfs: delete unnecessary assignment in vfs_listxattr
Documentation: filesystems: update filesystem locking documentation
vfs: namei: use path_equal() in follow_dotdot()
fs.h: fix outdated comment about file flags
__inode_security_revalidate() never gets NULL opt_dentry
make xattr_getsecurity() static
vfat: simplify checks in vfat_lookup()
get rid of dead code in d_find_alias()
it's SB_BORN, not MS_BORN...
msdos_rmdir(): kill BS comment
remove rpc_rmdir()
fs: avoid fdput() after failed fdget() in vfs_dedupe_file_range()
12 May, 2018
1 commit
-
We recently had an oops reported on a 4.14 kernel in
xfs_reclaim_inodes_count() where sb->s_fs_info pointed to garbage
and so the m_perag_tree lookup walked into lala land. It produces
an oops down this path during the failed mount:radix_tree_gang_lookup_tag+0xc4/0x130
xfs_perag_get_tag+0x37/0xf0
xfs_reclaim_inodes_count+0x32/0x40
xfs_fs_nr_cached_objects+0x11/0x20
super_cache_count+0x35/0xc0
shrink_slab.part.66+0xb1/0x370
shrink_node+0x7e/0x1a0
try_to_free_pages+0x199/0x470
__alloc_pages_slowpath+0x3a1/0xd20
__alloc_pages_nodemask+0x1c3/0x200
cache_grow_begin+0x20b/0x2e0
fallback_alloc+0x160/0x200
kmem_cache_alloc+0x111/0x4e0The problem is that the superblock shrinker is running before the
filesystem structures it depends on have been fully set up. i.e.
the shrinker is registered in sget(), before ->fill_super() has been
called, and the shrinker can call into the filesystem before
fill_super() does it's setup work. Essentially we are exposed to
both use-after-free and use-before-initialisation bugs here.To fix this, add a check for the SB_BORN flag in super_cache_count.
In general, this flag is not set until ->fs_mount() completes
successfully, so we know that it is set after the filesystem
setup has completed. This matches the trylock_super() behaviour
which will not let super_cache_scan() run if SB_BORN is not set, and
hence will not allow the superblock shrinker from entering the
filesystem while it is being set up or after it has failed setup
and is being torn down.Cc: stable@kernel.org
Signed-Off-By: Dave Chinner
Signed-off-by: Al Viro
11 May, 2018
1 commit
-
Signed-off-by: Al Viro
16 Apr, 2018
1 commit
-
syzbot is catching so many bugs triggered by commit 9ee332d99e4d5a97
("sget(): handle failures of register_shrinker()"). That commit expected
that calling kill_sb() from deactivate_locked_super() without successful
fill_super() is safe, but the reality was different; some callers assign
attributes which are needed for kill_sb() after sget() succeeds.For example, [1] is a report where sb->s_mode (which seems to be either
FMODE_READ | FMODE_EXCL | FMODE_WRITE or FMODE_READ | FMODE_EXCL) is not
assigned unless sget() succeeds. But it does not worth complicate sget()
so that register_shrinker() failure path can safely call
kill_block_super() via kill_sb(). Making alloc_super() fail if memory
allocation for register_shrinker() failed is much simpler. Let's avoid
calling deactivate_locked_super() from sget_userns() by preallocating
memory for the shrinker and making register_shrinker() in sget_userns()
never fail.[1] https://syzkaller.appspot.com/bug?id=588996a25a2587be2e3a54e8646728fb9cae44e7
Signed-off-by: Tetsuo Handa
Reported-by: syzbot
Cc: Al Viro
Cc: Michal Hocko
Signed-off-by: Al Viro
13 Apr, 2018
1 commit
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Pull vfs thaw updates from Al Viro:
"An ancient series that has fallen through the cracks in the previous
cycle"* 'work.thaw' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
buffer.c: call thaw_super during emergency thaw
vfs: factor sb iteration out of do_emergency_remount
19 Mar, 2018
1 commit
-
There are 2 distinct freezing mechanisms - one operates on block
devices and another one directly on super blocks. Both end up with the
same result, but thaw of only one of these does not thaw the other.In particular fsfreeze --freeze uses the ioctl variant going to the
super block. Since prior to this patch emergency thaw was not doing
a relevant thaw, filesystems frozen with this method remained
unaffected.The patch is a hack which adds blind unfreezing.
In order to keep the super block write-locked the whole time the code
is shuffled around and the newly introduced __iterate_supers is
employed.Signed-off-by: Mateusz Guzik
Signed-off-by: Al Viro
01 Feb, 2018
1 commit
-
Pull misc vfs updates from Al Viro:
"All kinds of misc stuff, without any unifying topic, from various
people.Neil's d_anon patch, several bugfixes, introduction of kvmalloc
analogue of kmemdup_user(), extending bitfield.h to deal with
fixed-endians, assorted cleanups all over the place..."* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits)
alpha: osf_sys.c: use timespec64 where appropriate
alpha: osf_sys.c: fix put_tv32 regression
jffs2: Fix use-after-free bug in jffs2_iget()'s error handling path
dcache: delete unused d_hash_mask
dcache: subtract d_hash_shift from 32 in advance
fs/buffer.c: fold init_buffer() into init_page_buffers()
fs: fold __inode_permission() into inode_permission()
fs: add RWF_APPEND
sctp: use vmemdup_user() rather than badly open-coding memdup_user()
snd_ctl_elem_init_enum_names(): switch to vmemdup_user()
replace_user_tlv(): switch to vmemdup_user()
new primitive: vmemdup_user()
memdup_user(): switch to GFP_USER
eventfd: fold eventfd_ctx_get() into eventfd_ctx_fileget()
eventfd: fold eventfd_ctx_read() into eventfd_read()
eventfd: convert to use anon_inode_getfd()
nfs4file: get rid of pointless include of btrfs.h
uvc_v4l2: clean copyin/copyout up
vme_user: don't use __copy_..._user()
usx2y: don't bother with memdup_user() for 16-byte structure
...
26 Dec, 2017
1 commit
-
The original purpose of the per-superblock d_anon list was to
keep disconnected dentries in the cache between consecutive
requests to the NFS server. Dentries can be disconnected if
a client holds a file open and repeatedly performs IO on it,
and if the server drops the dentry, whether due to memory
pressure, server restart, or "echo 3 > /proc/sys/vm/drop_caches".This purpose was thwarted by commit 75a6f82a0d10 ("freeing unlinked
file indefinitely delayed") which caused disconnected dentries
to be freed as soon as their refcount reached zero.This means that, when a dentry being used by nfsd gets disconnected, a
new one needs to be allocated for every request (unless requests
overlap). As the dentry has no name, no parent, and no children,
there is little of value to cache. As small memory allocations are
typically fast (from per-cpu free lists) this likely has little cost.This means that the original purpose of s_anon is no longer relevant:
there is no longer any need to keep disconnected dentries on a list so
they appear to be hashed.However, s_anon now has a new use. When you mount an NFS filesystem,
the dentry stored in s_root is just a placebo. The "real" root dentry
is allocated using d_obtain_root() and so it kept on the s_anon list.
I don't know the reason for this, but suspect it related to NFSv4
where a mount of "server:/some/path" require NFS to look up the root
filehandle on the server, then walk down "/some" and "/path" to get
the filehandle to mount.Whatever the reason, NFS depends on the s_anon list and on
shrink_dcache_for_umount() pruning all dentries on this list. So we
cannot simply remove s_anon.We could just leave the code unchanged, but apart from that being
potentially confusing, the (unfair) bit-spin-lock which protects
s_anon can become a bottle neck when lots of disconnected dentries are
being created.So this patch renames s_anon to s_roots, and stops storing
disconnected dentries on the list. Only dentries obtained with
d_obtain_root() are now stored on this list. There are many fewer of
these (only NFS and NILFS2 use the call, and only during filesystem
mount) so contention on the bit-lock will not be a problem.Possibly an alternate solution should be found for NFS and NILFS2, but
that would require understanding their needs first.Signed-off-by: NeilBrown
Signed-off-by: Al Viro
19 Dec, 2017
1 commit
-
Signed-off-by: Al Viro
05 Dec, 2017
1 commit
-
... so that failure exits could count on it having been
done.Signed-off-by: Al Viro
18 Nov, 2017
1 commit
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Pull misc vfs updates from Al Viro:
"Assorted stuff, really no common topic here"* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
vfs: grab the lock instead of blocking in __fd_install during resizing
vfs: stop clearing close on exec when closing a fd
include/linux/fs.h: fix comment about struct address_space
fs: make fiemap work from compat_ioctl
coda: fix 'kernel memory exposure attempt' in fsync
pstore: remove unneeded unlikely()
vfs: remove unneeded unlikely()
stubs for mount_bdev() and kill_block_super() in !CONFIG_BLOCK case
make vfs_ustat() static
do_handle_open() should be static
elf_fdpic: fix unused variable warning
fold destroy_super() into __put_super()
new helper: destroy_unused_super()
fix address space warnings in ipc/
acct.h: get rid of detritus
02 Nov, 2017
1 commit
-
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.By default all files without license information are under the default
license of the kernel, which is GPL version 2.Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if
Reviewed-by: Philippe Ombredanne
Reviewed-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
12 Oct, 2017
2 commits
-
There's only one caller of destroy_super() left now. Fold it there,
and replace those list_lru_destroy() calls with checks that they
had already been done (as they should have, when we were dropping
the last active reference).Signed-off-by: Al Viro
-
Used for disposal of super_block instances that had never been reachable
via any shared data structures. No need for RCU delay in there, everything
can be called directly.Signed-off-by: Al Viro
05 Oct, 2017
1 commit
-
The intent is to reduce code duplication with other code
iterating the list.No functional changes.
Signed-off-by: Mateusz Guzik
Signed-off-by: Al Viro
15 Sep, 2017
1 commit
-
Pull mount flag updates from Al Viro:
"Another chunk of fmount preparations from dhowells; only trivial
conflicts for that part. It separates MS_... bits (very grotty
mount(2) ABI) from the struct super_block ->s_flags (kernel-internal,
only a small subset of MS_... stuff).This does *not* convert the filesystems to new constants; only the
infrastructure is done here. The next step in that series is where the
conflicts would be; that's the conversion of filesystems. It's purely
mechanical and it's better done after the merge, so if you could run
something likelist=$(for i in MS_RDONLY MS_NOSUID MS_NODEV MS_NOEXEC MS_SYNCHRONOUS MS_MANDLOCK MS_DIRSYNC MS_NOATIME MS_NODIRATIME MS_SILENT MS_POSIXACL MS_KERNMOUNT MS_I_VERSION MS_LAZYTIME; do git grep -l $i fs drivers/staging/lustre drivers/mtd ipc mm include/linux; done|sort|uniq|grep -v '^fs/namespace.c$')
sed -i -e 's/\/SB_RDONLY/g' \
-e 's/\/SB_NOSUID/g' \
-e 's/\/SB_NODEV/g' \
-e 's/\/SB_NOEXEC/g' \
-e 's/\/SB_SYNCHRONOUS/g' \
-e 's/\/SB_MANDLOCK/g' \
-e 's/\/SB_DIRSYNC/g' \
-e 's/\/SB_NOATIME/g' \
-e 's/\/SB_NODIRATIME/g' \
-e 's/\/SB_SILENT/g' \
-e 's/\/SB_POSIXACL/g' \
-e 's/\/SB_KERNMOUNT/g' \
-e 's/\/SB_I_VERSION/g' \
-e 's/\/SB_LAZYTIME/g' \
$listand commit it with something along the lines of 'convert filesystems
away from use of MS_... constants' as commit message, it would save a
quite a bit of headache next cycle"* 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
VFS: Differentiate mount flags (MS_*) from internal superblock flags
VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)
vfs: Add sb_rdonly(sb) to query the MS_RDONLY flag on s_flags
18 Aug, 2017
1 commit
-
Convert dqio_mutex to rwsem and call it dqio_sem. No functional changes
yet.Signed-off-by: Jan Kara
17 Jul, 2017
2 commits
-
Differentiate the MS_* flags passed to mount(2) from the internal flags set
in the super_block's s_flags. s_flags are now called SB_*, with the names
and the values for the moment mirroring the MS_* flags that they're
equivalent to.In this patch, just the headers are altered and some kernel code where
blind automated conversion isn't necessarily correct.Note that this shows up some interesting issues:
(1) Some MS_* flags get translated to MNT_* flags (such as MS_NODEV ->
MNT_NODEV) without passing this on to the filesystem, but some
filesystems set such flags anyway.(2) The ->remount_fs() methods of some filesystems adjust the *flags
argument by setting MS_* flags in it, such as MS_NOATIME - but these
flags are then scrubbed by do_remount_sb() (only the occupants of
MS_RMT_MASK are permitted: MS_RDONLY, MS_SYNCHRONOUS, MS_MANDLOCK,
MS_I_VERSION and MS_LAZYTIME)I'm not sure what's the best way to solve all these cases.
Suggested-by: Al Viro
Signed-off-by: David Howells -
Firstly by applying the following with coccinelle's spatch:
@@ expression SB; @@
-SB->s_flags & MS_RDONLY
+sb_rdonly(SB)to effect the conversion to sb_rdonly(sb), then by applying:
@@ expression A, SB; @@
(
-(!sb_rdonly(SB)) && A
+!sb_rdonly(SB) && A
|
-A != (sb_rdonly(SB))
+A != sb_rdonly(SB)
|
-A == (sb_rdonly(SB))
+A == sb_rdonly(SB)
|
-!(sb_rdonly(SB))
+!sb_rdonly(SB)
|
-A && (sb_rdonly(SB))
+A && sb_rdonly(SB)
|
-A || (sb_rdonly(SB))
+A || sb_rdonly(SB)
|
-(sb_rdonly(SB)) != A
+sb_rdonly(SB) != A
|
-(sb_rdonly(SB)) == A
+sb_rdonly(SB) == A
|
-(sb_rdonly(SB)) && A
+sb_rdonly(SB) && A
|
-(sb_rdonly(SB)) || A
+sb_rdonly(SB) || A
)@@ expression A, B, SB; @@
(
-(sb_rdonly(SB)) ? 1 : 0
+sb_rdonly(SB)
|
-(sb_rdonly(SB)) ? A : B
+sb_rdonly(SB) ? A : B
)to remove left over excess bracketage and finally by applying:
@@ expression A, SB; @@
(
-(A & MS_RDONLY) != sb_rdonly(SB)
+(bool)(A & MS_RDONLY) != sb_rdonly(SB)
|
-(A & MS_RDONLY) == sb_rdonly(SB)
+(bool)(A & MS_RDONLY) == sb_rdonly(SB)
)to make comparisons against the result of sb_rdonly() (which is a bool)
work correctly.Signed-off-by: David Howells
11 Jul, 2017
1 commit
-
Kill off s_options, save/replace_mount_options() and generic_show_options()
as all filesystems now implement ->show_options() for themselves. This
should make it easier to implement a context-based mount where the mount
options can be passed individually over a file descriptor.Signed-off-by: David Howells
Signed-off-by: Al Viro
06 Jul, 2017
1 commit
-
Clean up line terminal whitespace in fs/namespace.c and fs/super.c.
Signed-off-by: David Howells
Signed-off-by: Al Viro
21 Apr, 2017
4 commits
-
Drop 'parent' argument of bdi_register() and bdi_register_va(). It is
always NULL.Reviewed-by: Christoph Hellwig
Signed-off-by: Jan Kara
Signed-off-by: Jens Axboe -
Now that all bdi structures filesystems use are properly refcounted, we
can remove the SB_I_DYNBDI flag.Reviewed-by: Christoph Hellwig
Signed-off-by: Jan Kara
Signed-off-by: Jens Axboe -
So far we just relied on block device to hold a bdi reference for us
while the filesystem is mounted. While that works perfectly fine, it is
a bit awkward that we have a pointer to a refcounted structure in the
superblock without proper reference. So make s_bdi hold a proper
reference to block device's BDI. No filesystem using mount_bdev()
actually changes s_bdi so this is safe and will make bdev filesystems
work the same way as filesystems needing to set up their private bdi.Reviewed-by: Christoph Hellwig
Signed-off-by: Jan Kara
Signed-off-by: Jens Axboe -
Provide helper functions for setting up dynamically allocated
backing_dev_info structures for filesystems and cleaning them up on
superblock destruction.CC: linux-mtd@lists.infradead.org
CC: linux-nfs@vger.kernel.org
CC: Petr Vandrovec
CC: linux-nilfs@vger.kernel.org
CC: cluster-devel@redhat.com
CC: osd-dev@open-osd.org
CC: codalist@coda.cs.cmu.edu
CC: linux-afs@lists.infradead.org
CC: ecryptfs@vger.kernel.org
CC: linux-cifs@vger.kernel.org
CC: ceph-devel@vger.kernel.org
CC: linux-btrfs@vger.kernel.org
CC: v9fs-developer@lists.sourceforge.net
CC: lustre-devel@lists.lustre.org
Reviewed-by: Christoph Hellwig
Signed-off-by: Jan Kara
Signed-off-by: Jens Axboe
24 Feb, 2017
1 commit
-
Pull namespace updates from Eric Biederman:
"There is a lot here. A lot of these changes result in subtle user
visible differences in kernel behavior. I don't expect anything will
care but I will revert/fix things immediately if any regressions show
up.From Seth Forshee there is a continuation of the work to make the vfs
ready for unpriviled mounts. We had thought the previous changes
prevented the creation of files outside of s_user_ns of a filesystem,
but it turns we missed the O_CREAT path. Ooops.Pavel Tikhomirov and Oleg Nesterov worked together to fix a long
standing bug in the implemenation of PR_SET_CHILD_SUBREAPER where only
children that are forked after the prctl are considered and not
children forked before the prctl. The only known user of this prctl
systemd forks all children after the prctl. So no userspace
regressions will occur. Holding earlier forked children to the same
rules as later forked children creates a semantic that is sane enough
to allow checkpoing of processes that use this feature.There is a long delayed change by Nikolay Borisov to limit inotify
instances inside a user namespace.Michael Kerrisk extends the API for files used to maniuplate
namespaces with two new trivial ioctls to allow discovery of the
hierachy and properties of namespaces.Konstantin Khlebnikov with the help of Al Viro adds code that when a
network namespace exits purges it's sysctl entries from the dcache. As
in some circumstances this could use a lot of memory.Vivek Goyal fixed a bug with stacked filesystems where the permissions
on the wrong inode were being checked.I continue previous work on ptracing across exec. Allowing a file to
be setuid across exec while being ptraced if the tracer has enough
credentials in the user namespace, and if the process has CAP_SETUID
in it's own namespace. Proc files for setuid or otherwise undumpable
executables are now owned by the root in the user namespace of their
mm. Allowing debugging of setuid applications in containers to work
better.A bug I introduced with permission checking and automount is now
fixed. The big change is to mark the mounts that the kernel initiates
as a result of an automount. This allows the permission checks in sget
to be safely suppressed for this kind of mount. As the permission
check happened when the original filesystem was mounted.Finally a special case in the mount namespace is removed preventing
unbounded chains in the mount hash table, and making the semantics
simpler which benefits CRIU.The vfs fix along with related work in ima and evm I believe makes us
ready to finish developing and merge fully unprivileged mounts of the
fuse filesystem. The cleanups of the mount namespace makes discussing
how to fix the worst case complexity of umount. The stacked filesystem
fixes pave the way for adding multiple mappings for the filesystem
uids so that efficient and safer containers can be implemented"* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
proc/sysctl: Don't grab i_lock under sysctl_lock.
vfs: Use upper filesystem inode in bprm_fill_uid()
proc/sysctl: prune stale dentries during unregistering
mnt: Tuck mounts under others instead of creating shadow/side mounts.
prctl: propagate has_child_subreaper flag to every descendant
introduce the walk_process_tree() helper
nsfs: Add an ioctl() to return owner UID of a userns
fs: Better permission checking for submounts
exit: fix the setns() && PR_SET_CHILD_SUBREAPER interaction
vfs: open() with O_CREAT should not create inodes with unknown ids
nsfs: Add an ioctl() to return the namespace type
proc: Better ownership of files for non-dumpable tasks in user namespaces
exec: Remove LSM_UNSAFE_PTRACE_CAP
exec: Test the ptracer's saved cred to see if the tracee can gain caps
exec: Don't reset euid and egid when the tracee has CAP_SETUID
inotify: Convert to using per-namespace limits
02 Feb, 2017
1 commit
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We will want to have struct backing_dev_info allocated separately from
struct request_queue. As the first step add pointer to backing_dev_info
to request_queue and convert all users touching it. No functional
changes in this patch.Reviewed-by: Christoph Hellwig
Signed-off-by: Jan Kara
Signed-off-by: Jens Axboe
01 Feb, 2017
1 commit
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To support unprivileged users mounting filesystems two permission
checks have to be performed: a test to see if the user allowed to
create a mount in the mount namespace, and a test to see if
the user is allowed to access the specified filesystem.The automount case is special in that mounting the original filesystem
grants permission to mount the sub-filesystems, to any user who
happens to stumble across the their mountpoint and satisfies the
ordinary filesystem permission checks.Attempting to handle the automount case by using override_creds
almost works. It preserves the idea that permission to mount
the original filesystem is permission to mount the sub-filesystem.
Unfortunately using override_creds messes up the filesystems
ordinary permission checks.Solve this by being explicit that a mount is a submount by introducing
vfs_submount, and using it where appropriate.vfs_submount uses a new mount internal mount flags MS_SUBMOUNT, to let
sget and friends know that a mount is a submount so they can take appropriate
action.sget and sget_userns are modified to not perform any permission checks
on submounts.follow_automount is modified to stop using override_creds as that
has proven problemantic.do_mount is modified to always remove the new MS_SUBMOUNT flag so
that we know userspace will never by able to specify it.autofs4 is modified to stop using current_real_cred that was put in
there to handle the previous version of submount permission checking.cifs is modified to pass the mountpoint all of the way down to vfs_submount.
debugfs is modified to pass the mountpoint all of the way down to
trace_automount by adding a new parameter. To make this change easier
a new typedef debugfs_automount_t is introduced to capture the type of
the debugfs automount function.Cc: stable@vger.kernel.org
Fixes: 069d5ac9ae0d ("autofs: Fix automounts by using current_real_cred()->uid")
Fixes: aeaa4a79ff6a ("fs: Call d_automount with the filesystems creds")
Reviewed-by: Trond Myklebust
Reviewed-by: Seth Forshee
Signed-off-by: "Eric W. Biederman"
30 Nov, 2016
1 commit
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The only places that were grabbing dqonoff_mutex are functions turning
quotas on and off and these are properly serialized using s_umount
semaphore. Remove dqonoff_mutex.Signed-off-by: Jan Kara
23 Nov, 2016
1 commit
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Quota code will need a variant of get_super_thawed() that returns
superblock with s_umount held in exclusive mode to serialize quota on
and quota off operations. Provide this functionality.Signed-off-by: Jan Kara
15 Oct, 2016
2 commits
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sb_wait_write()->percpu_rwsem_release() fools lockdep to avoid the
false-positives. Now that xfs was fixed by Dave's commit dbad7c993053
("xfs: stop holding ILOCK over filldir callbacks") we can remove it and
change freeze_super() and thaw_super() to run with s_writers.rw_sem locks
held; we add two trivial helpers for that, lockdep_sb_freeze_release()
and lockdep_sb_freeze_acquire().xfstests-dev/check `grep -il freeze tests/*/???` does not trigger any
warning from lockdep.Signed-off-by: Oleg Nesterov
Signed-off-by: Al Viro -
Change thaw_super() to check frozen != SB_FREEZE_COMPLETE rather than
frozen == SB_UNFROZEN, otherwise it can race with freeze_super() which
drops sb->s_umount after SB_FREEZE_WRITE to preserve the lock ordering.In this case thaw_super() will wrongly call s_op->unfreeze_fs() before
it was actually frozen, and call sb_freeze_unlock() which leads to the
unbalanced percpu_up_write(). Unfortunately lockdep can't detect this,
so this triggers misc BUG_ON()'s in kernel/rcu/sync.c.Reported-and-tested-by: Nikolay Borisov
Signed-off-by: Oleg Nesterov
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro
30 Jul, 2016
1 commit
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Pull userns vfs updates from Eric Biederman:
"This tree contains some very long awaited work on generalizing the
user namespace support for mounting filesystems to include filesystems
with a backing store. The real world target is fuse but the goal is
to update the vfs to allow any filesystem to be supported. This
patchset is based on a lot of code review and testing to approach that
goal.While looking at what is needed to support the fuse filesystem it
became clear that there were things like xattrs for security modules
that needed special treatment. That the resolution of those concerns
would not be fuse specific. That sorting out these general issues
made most sense at the generic level, where the right people could be
drawn into the conversation, and the issues could be solved for
everyone.At a high level what this patchset does a couple of simple things:
- Add a user namespace owner (s_user_ns) to struct super_block.
- Teach the vfs to handle filesystem uids and gids not mapping into
to kuids and kgids and being reported as INVALID_UID and
INVALID_GID in vfs data structures.By assigning a user namespace owner filesystems that are mounted with
only user namespace privilege can be detected. This allows security
modules and the like to know which mounts may not be trusted. This
also allows the set of uids and gids that are communicated to the
filesystem to be capped at the set of kuids and kgids that are in the
owning user namespace of the filesystem.One of the crazier corner casees this handles is the case of inodes
whose i_uid or i_gid are not mapped into the vfs. Most of the code
simply doesn't care but it is easy to confuse the inode writeback path
so no operation that could cause an inode write-back is permitted for
such inodes (aka only reads are allowed).This set of changes starts out by cleaning up the code paths involved
in user namespace permirted mounts. Then when things are clean enough
adds code that cleanly sets s_user_ns. Then additional restrictions
are added that are possible now that the filesystem superblock
contains owner information.These changes should not affect anyone in practice, but there are some
parts of these restrictions that are changes in behavior.- Andy's restriction on suid executables that does not honor the
suid bit when the path is from another mount namespace (think
/proc/[pid]/fd/) or when the filesystem was mounted by a less
privileged user.- The replacement of the user namespace implicit setting of MNT_NODEV
with implicitly setting SB_I_NODEV on the filesystem superblock
instead.Using SB_I_NODEV is a stronger form that happens to make this state
user invisible. The user visibility can be managed but it caused
problems when it was introduced from applications reasonably
expecting mount flags to be what they were set to.There is a little bit of work remaining before it is safe to support
mounting filesystems with backing store in user namespaces, beyond
what is in this set of changes.- Verifying the mounter has permission to read/write the block device
during mount.- Teaching the integrity modules IMA and EVM to handle filesystems
mounted with only user namespace root and to reduce trust in their
security xattrs accordingly.- Capturing the mounters credentials and using that for permission
checks in d_automount and the like. (Given that overlayfs already
does this, and we need the work in d_automount it make sense to
generalize this case).Furthermore there are a few changes that are on the wishlist:
- Get all filesystems supporting posix acls using the generic posix
acls so that posix_acl_fix_xattr_from_user and
posix_acl_fix_xattr_to_user may be removed. [Maintainability]- Reducing the permission checks in places such as remount to allow
the superblock owner to perform them.- Allowing the superblock owner to chown files with unmapped uids and
gids to something that is mapped so the files may be treated
normally.I am not considering even obvious relaxations of permission checks
until it is clear there are no more corner cases that need to be
locked down and handled generically.Many thanks to Seth Forshee who kept this code alive, and putting up
with me rewriting substantial portions of what he did to handle more
corner cases, and for his diligent testing and reviewing of my
changes"* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (30 commits)
fs: Call d_automount with the filesystems creds
fs: Update i_[ug]id_(read|write) to translate relative to s_user_ns
evm: Translate user/group ids relative to s_user_ns when computing HMAC
dquot: For now explicitly don't support filesystems outside of init_user_ns
quota: Handle quota data stored in s_user_ns in quota_setxquota
quota: Ensure qids map to the filesystem
vfs: Don't create inodes with a uid or gid unknown to the vfs
vfs: Don't modify inodes with a uid or gid unknown to the vfs
cred: Reject inodes with invalid ids in set_create_file_as()
fs: Check for invalid i_uid in may_follow_link()
vfs: Verify acls are valid within superblock's s_user_ns.
userns: Handle -1 in k[ug]id_has_mapping when !CONFIG_USER_NS
fs: Refuse uid/gid changes which don't map into s_user_ns
selinux: Add support for unprivileged mounts from user namespaces
Smack: Handle labels consistently in untrusted mounts
Smack: Add support for unprivileged mounts from user namespaces
fs: Treat foreign mounts as nosuid
fs: Limit file caps to the user namespace of the super block
userns: Remove the now unnecessary FS_USERNS_DEV_MOUNT flag
userns: Remove implicit MNT_NODEV fragility.
...
27 Jul, 2016
1 commit
-
wait_sb_inodes() currently does a walk of all inodes in the filesystem
to find dirty one to wait on during sync. This is highly inefficient
and wastes a lot of CPU when there are lots of clean cached inodes that
we don't need to wait on.To avoid this "all inode" walk, we need to track inodes that are
currently under writeback that we need to wait for. We do this by
adding inodes to a writeback list on the sb when the mapping is first
tagged as having pages under writeback. wait_sb_inodes() can then walk
this list of "inodes under IO" and wait specifically just for the inodes
that the current sync(2) needs to wait for.Define a couple helpers to add/remove an inode from the writeback list
and call them when the overall mapping is tagged for or cleared from
writeback. Update wait_sb_inodes() to walk only the inodes under
writeback due to the sync.With this change, filesystem sync times are significantly reduced for
fs' with largely populated inode caches and otherwise no other work to
do. For example, on a 16xcpu 2GHz x86-64 server, 10TB XFS filesystem
with a ~10m entry inode cache, sync times are reduced from ~7.3s to less
than 0.1s when the filesystem is fully clean.Link: http://lkml.kernel.org/r/1466594593-6757-2-git-send-email-bfoster@redhat.com
Signed-off-by: Dave Chinner
Signed-off-by: Josef Bacik
Signed-off-by: Brian Foster
Reviewed-by: Jan Kara
Tested-by: Holger Hoffstätte
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
24 Jun, 2016
1 commit
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Now that SB_I_NODEV controls the nodev behavior devpts can just clear
this flag during mount. Simplifying the code and making it easier
to audit how the code works. While still preserving the invariant
that s_iflags is only modified during mount.Acked-by: Seth Forshee
Signed-off-by: "Eric W. Biederman"