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2020-01-14fs/kernfs/dir.c: Clean code by removing always true conditionMateusz Nosek
Previously there was an additional check if variable pos is not null. However, this check happens after entering while loop and only then, which can happen only if pos is not null. Therefore the additional check is redundant and can be removed. Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20191230191628.21099-1-mateusznosek0@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-26Merge branch 'locking-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: "The main changes in this cycle were: - A comprehensive rewrite of the robust/PI futex code's exit handling to fix various exit races. (Thomas Gleixner et al) - Rework the generic REFCOUNT_FULL implementation using atomic_fetch_* operations so that the performance impact of the cmpxchg() loops is mitigated for common refcount operations. With these performance improvements the generic implementation of refcount_t should be good enough for everybody - and this got confirmed by performance testing, so remove ARCH_HAS_REFCOUNT and REFCOUNT_FULL entirely, leaving the generic implementation enabled unconditionally. (Will Deacon) - Other misc changes, fixes, cleanups" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits) lkdtm: Remove references to CONFIG_REFCOUNT_FULL locking/refcount: Remove unused 'refcount_error_report()' function locking/refcount: Consolidate implementations of refcount_t locking/refcount: Consolidate REFCOUNT_{MAX,SATURATED} definitions locking/refcount: Move saturation warnings out of line locking/refcount: Improve performance of generic REFCOUNT_FULL code locking/refcount: Move the bulk of the REFCOUNT_FULL implementation into the <linux/refcount.h> header locking/refcount: Remove unused refcount_*_checked() variants locking/refcount: Ensure integer operands are treated as signed locking/refcount: Define constants for saturation and max refcount values futex: Prevent exit livelock futex: Provide distinct return value when owner is exiting futex: Add mutex around futex exit futex: Provide state handling for exec() as well futex: Sanitize exit state handling futex: Mark the begin of futex exit explicitly futex: Set task::futex_state to DEAD right after handling futex exit futex: Split futex_mm_release() for exit/exec exit/exec: Seperate mm_release() futex: Replace PF_EXITPIDONE with a state ...
2019-11-12kernfs: use 64bit inos if ino_t is 64bitTejun Heo
Each kernfs_node is identified with a 64bit ID. The low 32bit is exposed as ino and the high gen. While this already allows using inos as keys by looking up with wildcard generation number of 0, it's adding unnecessary complications for 64bit ino archs which can directly use kernfs_node IDs as inos to uniquely identify each cgroup instance. This patch exposes IDs directly as inos on 64bit ino archs. The conversion is mostly straight-forward. * 32bit ino archs behave the same as before. 64bit ino archs now use the whole 64bit ID as ino and the generation number is fixed at 1. * 64bit inos still use the same idr allocator which gurantees that the lower 32bits identify the current live instance uniquely and the high 32bits are incremented whenever the low bits wrap. As the upper 32bits are no longer used as gen and we don't wanna start ino allocation with 33rd bit set, the initial value for highbits allocation is changed to 0 on 64bit ino archs. * blktrace exposes two 32bit numbers - (INO,GEN) pair - to identify the issuing cgroup. Userland builds FILEID_INO32_GEN fids from these numbers to look up the cgroups. To remain compatible with the behavior, always output (LOW32,HIGH32) which will be constructed back to the original 64bit ID by __kernfs_fh_to_dentry(). Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Namhyung Kim <namhyung@kernel.org>
2019-11-12kernfs: combine ino/id lookup functions into kernfs_find_and_get_node_by_id()Tejun Heo
kernfs_find_and_get_node_by_ino() looks the kernfs_node matching the specified ino. On top of that, kernfs_get_node_by_id() and kernfs_fh_get_inode() implement full ID matching by testing the rest of ID. On surface, confusingly, the two are slightly different in that the latter uses 0 gen as wildcard while the former doesn't - does it mean that the latter can't uniquely identify inodes w/ 0 gen? In practice, this is a distinction without a difference because generation number starts at 1. There are no actual IDs with 0 gen, so it can always safely used as wildcard. Let's simplify the code by renaming kernfs_find_and_get_node_by_ino() to kernfs_find_and_get_node_by_id(), moving all lookup logics into it, and removing now unnecessary kernfs_get_node_by_id(). Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-12kernfs: convert kernfs_node->id from union kernfs_node_id to u64Tejun Heo
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>
2019-11-12kernfs: kernfs_find_and_get_node_by_ino() should only look up activated nodesTejun Heo
kernfs node can be created in two separate steps - allocation and activation. This is used to make kernfs nodes visible only after the internal states attached to the node are fully initialized. kernfs_find_and_get_node_by_id() currently allows lookups of nodes which aren't activated yet and thus can expose nodes are which are still being prepped by kernfs users. Fix it by disallowing lookups of nodes which aren't activated yet. kernfs_find_and_get_node_by_ino() Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Namhyung Kim <namhyung@kernel.org>
2019-11-12kernfs: use dumber locking for kernfs_find_and_get_node_by_ino()Tejun Heo
kernfs_find_and_get_node_by_ino() uses RCU protection. It's currently a bit buggy because it can look up a node which hasn't been activated yet and thus may end up exposing a node that the kernfs user is still prepping. While it can be fixed by pushing it further in the current direction, it's already complicated and isn't clear whether the complexity is justified. The main use of kernfs_find_and_get_node_by_ino() is for exportfs operations. They aren't super hot and all the follow-up operations (e.g. mapping to path) use normal locking anyway. Let's switch to a dumber locking scheme and protect the lookup with kernfs_idr_lock. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Namhyung Kim <namhyung@kernel.org>
2019-11-12kernfs: fix ino wrap-around detectionTejun Heo
When the 32bit ino wraps around, kernfs increments the generation number to distinguish reused ino instances. The wrap-around detection tests whether the allocated ino is lower than what the cursor but the cursor is pointing to the next ino to allocate so the condition never triggers. Fix it by remembering the last ino and comparing against that. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Fixes: 4a3ef68acacf ("kernfs: implement i_generation") Cc: Namhyung Kim <namhyung@kernel.org> Cc: stable@vger.kernel.org # v4.14+
2019-10-09locking/lockdep: Remove unused @nested argument from lock_release()Qian Cai
Since the following commit: b4adfe8e05f1 ("locking/lockdep: Remove unused argument in __lock_release") @nested is no longer used in lock_release(), so remove it from all lock_release() calls and friends. Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will@kernel.org> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: alexander.levin@microsoft.com Cc: daniel@iogearbox.net Cc: davem@davemloft.net Cc: dri-devel@lists.freedesktop.org Cc: duyuyang@gmail.com Cc: gregkh@linuxfoundation.org Cc: hannes@cmpxchg.org Cc: intel-gfx@lists.freedesktop.org Cc: jack@suse.com Cc: jlbec@evilplan.or Cc: joonas.lahtinen@linux.intel.com Cc: joseph.qi@linux.alibaba.com Cc: jslaby@suse.com Cc: juri.lelli@redhat.com Cc: maarten.lankhorst@linux.intel.com Cc: mark@fasheh.com Cc: mhocko@kernel.org Cc: mripard@kernel.org Cc: ocfs2-devel@oss.oracle.com Cc: rodrigo.vivi@intel.com Cc: sean@poorly.run Cc: st@kernel.org Cc: tj@kernel.org Cc: tytso@mit.edu Cc: vdavydov.dev@gmail.com Cc: vincent.guittot@linaro.org Cc: viro@zeniv.linux.org.uk Link: https://lkml.kernel.org/r/1568909380-32199-1-git-send-email-cai@lca.pw Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-07-25fs: kernfs: Fix possible null-pointer dereferences in ↵Jia-Ju Bai
kernfs_path_from_node_locked() In kernfs_path_from_node_locked(), there is an if statement on line 147 to check whether buf is NULL: if (buf) When buf is NULL, it is used on line 151: len += strlcpy(buf + len, parent_str, ...) and line 158: len += strlcpy(buf + len, "/", ...) and line 160: len += strlcpy(buf + len, kn->name, ...) Thus, possible null-pointer dereferences may occur. To fix these possible bugs, buf is checked before being used. If it is NULL, -EINVAL is returned. These bugs are found by a static analysis tool STCheck written by us. Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> Link: https://lore.kernel.org/r/20190724022242.27505-1-baijiaju1990@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-25kernfs: fix potential null pointer dereferencePeng Wang
Get root safely after kn is ensureed to be not null. Signed-off-by: Peng Wang <rocking@whu.edu.cn> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20190708151611.13242-1-rocking@whu.edu.cn Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-05treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428Thomas Gleixner
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>
2019-05-07Merge tag 'selinux-pr-20190507' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux Pull selinux updates from Paul Moore: "We've got a few SELinux patches for the v5.2 merge window, the highlights are below: - Add LSM hooks, and the SELinux implementation, for proper labeling of kernfs. While we are only including the SELinux implementation here, the rest of the LSM folks have given the hooks a thumbs-up. - Update the SELinux mdp (Make Dummy Policy) script to actually work on a modern system. - Disallow userspace to change the LSM credentials via /proc/self/attr when the task's credentials are already overridden. The change was made in procfs because all the LSM folks agreed this was the Right Thing To Do and duplicating it across each LSM was going to be annoying" * tag 'selinux-pr-20190507' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: proc: prevent changes to overridden credentials selinux: Check address length before reading address family kernfs: fix xattr name handling in LSM helpers MAINTAINERS: update SELinux file patterns selinux: avoid uninitialized variable warning selinux: remove useless assignments LSM: lsm_hooks.h - fix missing colon in docstring selinux: Make selinux_kernfs_init_security static kernfs: initialize security of newly created nodes selinux: implement the kernfs_init_security hook LSM: add new hook for kernfs node initialization kernfs: use simple_xattrs for security attributes selinux: try security xattr after genfs for kernfs filesystems kernfs: do not alloc iattrs in kernfs_xattr_get kernfs: clean up struct kernfs_iattrs scripts/selinux: fix build selinux: use kernel linux/socket.h for genheaders and mdp scripts/selinux: modernize mdp
2019-04-25kernfs: fix barrier usage in __kernfs_new_node()Andrea Parri
smp_mb__before_atomic() can not be applied to atomic_set(). Remove the barrier and rely on RELEASE synchronization. Fixes: ba16b2846a8c6 ("kernfs: add an API to get kernfs node from inode number") Cc: stable@vger.kernel.org Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-20kernfs: initialize security of newly created nodesOndrej Mosnacek
Use the new security_kernfs_init_security() hook to allow LSMs to possibly assign a non-default security context to a newly created kernfs node based on the attributes of the new node and also its parent node. This fixes an issue with cgroupfs under SELinux, where newly created cgroup subdirectories/files would not inherit its parent's context if it had been set explicitly to a non-default value (other than the genfs context specified by the policy). This can be reproduced as follows (on Fedora/RHEL): # mkdir /sys/fs/cgroup/unified/test # # Need permissive to change the label under Fedora policy: # setenforce 0 # chcon -t container_file_t /sys/fs/cgroup/unified/test # ls -lZ /sys/fs/cgroup/unified total 0 -r--r--r--. 1 root root system_u:object_r:cgroup_t:s0 0 Jan 29 03:06 cgroup.controllers -rw-r--r--. 1 root root system_u:object_r:cgroup_t:s0 0 Jan 29 03:06 cgroup.max.depth -rw-r--r--. 1 root root system_u:object_r:cgroup_t:s0 0 Jan 29 03:06 cgroup.max.descendants -rw-r--r--. 1 root root system_u:object_r:cgroup_t:s0 0 Jan 29 03:06 cgroup.procs -r--r--r--. 1 root root system_u:object_r:cgroup_t:s0 0 Jan 29 03:06 cgroup.stat -rw-r--r--. 1 root root system_u:object_r:cgroup_t:s0 0 Jan 29 03:06 cgroup.subtree_control -rw-r--r--. 1 root root system_u:object_r:cgroup_t:s0 0 Jan 29 03:06 cgroup.threads drwxr-xr-x. 2 root root system_u:object_r:cgroup_t:s0 0 Jan 29 03:06 init.scope drwxr-xr-x. 26 root root system_u:object_r:cgroup_t:s0 0 Jan 29 03:21 system.slice drwxr-xr-x. 3 root root system_u:object_r:container_file_t:s0 0 Jan 29 03:15 test drwxr-xr-x. 3 root root system_u:object_r:cgroup_t:s0 0 Jan 29 03:06 user.slice # mkdir /sys/fs/cgroup/unified/test/subdir Actual result: # ls -ldZ /sys/fs/cgroup/unified/test/subdir drwxr-xr-x. 2 root root system_u:object_r:cgroup_t:s0 0 Jan 29 03:15 /sys/fs/cgroup/unified/test/subdir Expected result: # ls -ldZ /sys/fs/cgroup/unified/test/subdir drwxr-xr-x. 2 root root unconfined_u:object_r:container_file_t:s0 0 Jan 29 03:15 /sys/fs/cgroup/unified/test/subdir Link: https://github.com/SELinuxProject/selinux-kernel/issues/39 Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-03-20kernfs: use simple_xattrs for security attributesOndrej Mosnacek
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>
2019-03-20kernfs: clean up struct kernfs_iattrsOndrej Mosnacek
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>
2019-02-08kernfs: Allocating memory for kernfs_iattrs with kmem_cache.Ayush Mittal
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>
2018-07-20kernfs: allow creating kernfs objects with arbitrary uid/gidDmitry Torokhov
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>
2018-06-05vfs: change inode times to use struct timespec64Deepa Dinamani
struct timespec is not y2038 safe. Transition vfs to use y2038 safe struct timespec64 instead. The change was made with the help of the following cocinelle script. This catches about 80% of the changes. All the header file and logic changes are included in the first 5 rules. The rest are trivial substitutions. I avoid changing any of the function signatures or any other filesystem specific data structures to keep the patch simple for review. The script can be a little shorter by combining different cases. But, this version was sufficient for my usecase. virtual patch @ depends on patch @ identifier now; @@ - struct timespec + struct timespec64 current_time ( ... ) { - struct timespec now = current_kernel_time(); + struct timespec64 now = current_kernel_time64(); ... - return timespec_trunc( + return timespec64_trunc( ... ); } @ depends on patch @ identifier xtime; @@ struct \( iattr \| inode \| kstat \) { ... - struct timespec xtime; + struct timespec64 xtime; ... } @ depends on patch @ identifier t; @@ struct inode_operations { ... int (*update_time) (..., - struct timespec t, + struct timespec64 t, ...); ... } @ depends on patch @ identifier t; identifier fn_update_time =~ "update_time$"; @@ fn_update_time (..., - struct timespec *t, + struct timespec64 *t, ...) { ... } @ depends on patch @ identifier t; @@ lease_get_mtime( ... , - struct timespec *t + struct timespec64 *t ) { ... } @te depends on patch forall@ identifier ts; local idexpression struct inode *inode_node; identifier i_xtime =~ "^i_[acm]time$"; identifier ia_xtime =~ "^ia_[acm]time$"; identifier fn_update_time =~ "update_time$"; identifier fn; expression e, E3; local idexpression struct inode *node1; local idexpression struct inode *node2; local idexpression struct iattr *attr1; local idexpression struct iattr *attr2; local idexpression struct iattr attr; identifier i_xtime1 =~ "^i_[acm]time$"; identifier i_xtime2 =~ "^i_[acm]time$"; identifier ia_xtime1 =~ "^ia_[acm]time$"; identifier ia_xtime2 =~ "^ia_[acm]time$"; @@ ( ( - struct timespec ts; + struct timespec64 ts; | - struct timespec ts = current_time(inode_node); + struct timespec64 ts = current_time(inode_node); ) <+... when != ts ( - timespec_equal(&inode_node->i_xtime, &ts) + timespec64_equal(&inode_node->i_xtime, &ts) | - timespec_equal(&ts, &inode_node->i_xtime) + timespec64_equal(&ts, &inode_node->i_xtime) | - timespec_compare(&inode_node->i_xtime, &ts) + timespec64_compare(&inode_node->i_xtime, &ts) | - timespec_compare(&ts, &inode_node->i_xtime) + timespec64_compare(&ts, &inode_node->i_xtime) | ts = current_time(e) | fn_update_time(..., &ts,...) | inode_node->i_xtime = ts | node1->i_xtime = ts | ts = inode_node->i_xtime | <+... attr1->ia_xtime ...+> = ts | ts = attr1->ia_xtime | ts.tv_sec | ts.tv_nsec | btrfs_set_stack_timespec_sec(..., ts.tv_sec) | btrfs_set_stack_timespec_nsec(..., ts.tv_nsec) | - ts = timespec64_to_timespec( + ts = ... -) | - ts = ktime_to_timespec( + ts = ktime_to_timespec64( ...) | - ts = E3 + ts = timespec_to_timespec64(E3) | - ktime_get_real_ts(&ts) + ktime_get_real_ts64(&ts) | fn(..., - ts + timespec64_to_timespec(ts) ,...) ) ...+> ( <... when != ts - return ts; + return timespec64_to_timespec(ts); ...> ) | - timespec_equal(&node1->i_xtime1, &node2->i_xtime2) + timespec64_equal(&node1->i_xtime2, &node2->i_xtime2) | - timespec_equal(&node1->i_xtime1, &attr2->ia_xtime2) + timespec64_equal(&node1->i_xtime2, &attr2->ia_xtime2) | - timespec_compare(&node1->i_xtime1, &node2->i_xtime2) + timespec64_compare(&node1->i_xtime1, &node2->i_xtime2) | node1->i_xtime1 = - timespec_trunc(attr1->ia_xtime1, + timespec64_trunc(attr1->ia_xtime1, ...) | - attr1->ia_xtime1 = timespec_trunc(attr2->ia_xtime2, + attr1->ia_xtime1 = timespec64_trunc(attr2->ia_xtime2, ...) | - ktime_get_real_ts(&attr1->ia_xtime1) + ktime_get_real_ts64(&attr1->ia_xtime1) | - ktime_get_real_ts(&attr.ia_xtime1) + ktime_get_real_ts64(&attr.ia_xtime1) ) @ depends on patch @ struct inode *node; struct iattr *attr; identifier fn; identifier i_xtime =~ "^i_[acm]time$"; identifier ia_xtime =~ "^ia_[acm]time$"; expression e; @@ ( - fn(node->i_xtime); + fn(timespec64_to_timespec(node->i_xtime)); | fn(..., - node->i_xtime); + timespec64_to_timespec(node->i_xtime)); | - e = fn(attr->ia_xtime); + e = fn(timespec64_to_timespec(attr->ia_xtime)); ) @ depends on patch forall @ struct inode *node; struct iattr *attr; identifier i_xtime =~ "^i_[acm]time$"; identifier ia_xtime =~ "^ia_[acm]time$"; identifier fn; @@ { + struct timespec ts; <+... ( + ts = timespec64_to_timespec(node->i_xtime); fn (..., - &node->i_xtime, + &ts, ...); | + ts = timespec64_to_timespec(attr->ia_xtime); fn (..., - &attr->ia_xtime, + &ts, ...); ) ...+> } @ depends on patch forall @ struct inode *node; struct iattr *attr; struct kstat *stat; identifier ia_xtime =~ "^ia_[acm]time$"; identifier i_xtime =~ "^i_[acm]time$"; identifier xtime =~ "^[acm]time$"; identifier fn, ret; @@ { + struct timespec ts; <+... ( + ts = timespec64_to_timespec(node->i_xtime); ret = fn (..., - &node->i_xtime, + &ts, ...); | + ts = timespec64_to_timespec(node->i_xtime); ret = fn (..., - &node->i_xtime); + &ts); | + ts = timespec64_to_timespec(attr->ia_xtime); ret = fn (..., - &attr->ia_xtime, + &ts, ...); | + ts = timespec64_to_timespec(attr->ia_xtime); ret = fn (..., - &attr->ia_xtime); + &ts); | + ts = timespec64_to_timespec(stat->xtime); ret = fn (..., - &stat->xtime); + &ts); ) ...+> } @ depends on patch @ struct inode *node; struct inode *node2; identifier i_xtime1 =~ "^i_[acm]time$"; identifier i_xtime2 =~ "^i_[acm]time$"; identifier i_xtime3 =~ "^i_[acm]time$"; struct iattr *attrp; struct iattr *attrp2; struct iattr attr ; identifier ia_xtime1 =~ "^ia_[acm]time$"; identifier ia_xtime2 =~ "^ia_[acm]time$"; struct kstat *stat; struct kstat stat1; struct timespec64 ts; identifier xtime =~ "^[acmb]time$"; expression e; @@ ( ( node->i_xtime2 \| attrp->ia_xtime2 \| attr.ia_xtime2 \) = node->i_xtime1 ; | node->i_xtime2 = \( node2->i_xtime1 \| timespec64_trunc(...) \); | node->i_xtime2 = node->i_xtime1 = node->i_xtime3 = \(ts \| current_time(...) \); | node->i_xtime1 = node->i_xtime3 = \(ts \| current_time(...) \); | stat->xtime = node2->i_xtime1; | stat1.xtime = node2->i_xtime1; | ( node->i_xtime2 \| attrp->ia_xtime2 \) = attrp->ia_xtime1 ; | ( attrp->ia_xtime1 \| attr.ia_xtime1 \) = attrp2->ia_xtime2; | - e = node->i_xtime1; + e = timespec64_to_timespec( node->i_xtime1 ); | - e = attrp->ia_xtime1; + e = timespec64_to_timespec( attrp->ia_xtime1 ); | node->i_xtime1 = current_time(...); | node->i_xtime2 = node->i_xtime1 = node->i_xtime3 = - e; + timespec_to_timespec64(e); | node->i_xtime1 = node->i_xtime3 = - e; + timespec_to_timespec64(e); | - node->i_xtime1 = e; + node->i_xtime1 = timespec_to_timespec64(e); ) Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Cc: <anton@tuxera.com> Cc: <balbi@kernel.org> Cc: <bfields@fieldses.org> Cc: <darrick.wong@oracle.com> Cc: <dhowells@redhat.com> Cc: <dsterba@suse.com> Cc: <dwmw2@infradead.org> Cc: <hch@lst.de> Cc: <hirofumi@mail.parknet.co.jp> Cc: <hubcap@omnibond.com> Cc: <jack@suse.com> Cc: <jaegeuk@kernel.org> Cc: <jaharkes@cs.cmu.edu> Cc: <jslaby@suse.com> Cc: <keescook@chromium.org> Cc: <mark@fasheh.com> Cc: <miklos@szeredi.hu> Cc: <nico@linaro.org> Cc: <reiserfs-devel@vger.kernel.org> Cc: <richard@nod.at> Cc: <sage@redhat.com> Cc: <sfrench@samba.org> Cc: <swhiteho@redhat.com> Cc: <tj@kernel.org> Cc: <trond.myklebust@primarydata.com> Cc: <tytso@mit.edu> Cc: <viro@zeniv.linux.org.uk>
2017-07-29kernfs: introduce kernfs_node_idShaohua Li
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>
2017-07-29kernfs: don't set dentry->d_fsdataShaohua Li
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>
2017-07-29kernfs: add an API to get kernfs node from inode numberShaohua Li
Add an API to get kernfs node from inode number. We will need this to implement exportfs operations. This API will be used in blktrace too later, so it should be as fast as possible. To make the API lock free, kernfs node is freed in RCU context. And we depend on kernfs_node count/ino number to filter out stale kernfs nodes. 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>
2017-07-29kernfs: implement i_generationShaohua Li
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>
2017-07-29kernfs: use idr instead of ida to manage inode numberShaohua Li
kernfs uses ida to manage inode number. The problem is we can't get kernfs_node from inode number with ida. Switching to use idr, next patch will add an API to get kernfs_node from inode number. 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>
2017-02-27Merge branch 'for-4.11' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "Several noteworthy changes. - Parav's rdma controller is finally merged. It is very straight forward and can limit the abosolute numbers of common rdma constructs used by different cgroups. - kernel/cgroup.c got too chubby and disorganized. Created kernel/cgroup/ subdirectory and moved all cgroup related files under kernel/ there and reorganized the core code. This hurts for backporting patches but was long overdue. - cgroup v2 process listing reimplemented so that it no longer depends on allocating a buffer large enough to cache the entire result to sort and uniq the output. v2 has always mangled the sort order to ensure that users don't depend on the sorted output, so this shouldn't surprise anybody. This makes the pid listing functions use the same iterators that are used internally, which have to have the same iterating capabilities anyway. - perf cgroup filtering now works automatically on cgroup v2. This patch was posted a long time ago but somehow fell through the cracks. - misc fixes asnd documentation updates" * 'for-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (27 commits) kernfs: fix locking around kernfs_ops->release() callback cgroup: drop the matching uid requirement on migration for cgroup v2 cgroup, perf_event: make perf_event controller work on cgroup2 hierarchy cgroup: misc cleanups cgroup: call subsys->*attach() only for subsystems which are actually affected by migration cgroup: track migration context in cgroup_mgctx cgroup: cosmetic update to cgroup_taskset_add() rdmacg: Fixed uninitialized current resource usage cgroup: Add missing cgroup-v2 PID controller documentation. rdmacg: Added documentation for rdmacg IB/core: added support to use rdma cgroup controller rdmacg: Added rdma cgroup controller cgroup: fix a comment typo cgroup: fix RCU related sparse warnings cgroup: move namespace code to kernel/cgroup/namespace.c cgroup: rename functions for consistency cgroup: move v1 mount functions to kernel/cgroup/cgroup-v1.c cgroup: separate out cgroup1_kf_syscall_ops cgroup: refactor mount path and clearly distinguish v1 and v2 paths cgroup: move cgroup v1 specific code to kernel/cgroup/cgroup-v1.c ...
2017-02-10kernfs: handle null pointers while printing node name and pathKonstantin Khlebnikov
Null kernfs nodes could be found at cgroups during construction. It seems safer to handle these null pointers right in kernfs in the same way as printf prints "(null)" for null pointer string. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-12-27kernfs: add kernfs_ops->open/release() callbacksTejun Heo
Add ->open/release() methods to kernfs_ops. ->open() is called when the file is opened and ->release() when the file is either released or severed. These callbacks can be used, for example, to manage persistent caching objects over multiple seq_file iterations. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Acked-by: Zefan Li <lizefan@huawei.com>
2016-10-14Merge branch 'for-4.9' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: - tracepoints for basic cgroup management operations added - kernfs and cgroup path formatting functions updated to behave in the style of strlcpy() - non-critical bug fixes * 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: blkcg: Unlock blkcg_pol_mutex only once when cpd == NULL cgroup: fix error handling regressions in proc_cgroup_show() and cgroup_release_agent() cpuset: fix error handling regression in proc_cpuset_show() cgroup: add tracepoints for basic operations cgroup: make cgroup_path() and friends behave in the style of strlcpy() kernfs: remove kernfs_path_len() kernfs: make kernfs_path*() behave in the style of strlcpy() kernfs: add dummy implementation of kernfs_path_from_node()
2016-10-10Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 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
2016-10-07vfs: Remove {get,set,remove}xattr inode operationsAndreas Gruenbacher
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>
2016-10-06kernfs: Switch to generic xattr handlersAndreas Gruenbacher
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-09-27fs: rename "rename2" i_op to "rename"Miklos Szeredi
Generated patch: sed -i "s/\.rename2\t/\.rename\t\t/" `git grep -wl rename2` sed -i "s/\brename2\b/rename/g" `git grep -wl rename2` Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-09-27fs: make remaining filesystems use .rename2Miklos Szeredi
This is trivial to do: - add flags argument to foo_rename() - check if flags is zero - assign foo_rename() to .rename2 instead of .rename This doesn't mean it's impossible to support RENAME_NOREPLACE for these filesystems, but it is not trivial, like for local filesystems. RENAME_NOREPLACE must guarantee atomicity (i.e. it shouldn't be possible for a file to be created on one host while it is overwritten by rename on another host). Filesystems converted: 9p, afs, ceph, coda, ecryptfs, kernfs, lustre, ncpfs, nfs, ocfs2, orangefs. After this, we can get rid of the duplicate interfaces for rename. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: David Howells <dhowells@redhat.com> [AFS] Acked-by: Mike Marshall <hubcap@omnibond.com> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: Jan Harkes <jaharkes@cs.cmu.edu> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Oleg Drokin <oleg.drokin@intel.com> Cc: Trond Myklebust <trond.myklebust@primarydata.com> Cc: Mark Fasheh <mfasheh@suse.com>
2016-08-10kernfs: remove kernfs_path_len()Tejun Heo
It doesn't have any in-kernel user and the same result can be obtained from kernfs_path(@kn, NULL, 0). Remove it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Serge Hallyn <serge.hallyn@ubuntu.com>
2016-08-10kernfs: make kernfs_path*() behave in the style of strlcpy()Tejun Heo
kernfs_path*() functions always return the length of the full path but the path content is undefined if the length is larger than the provided buffer. This makes its behavior different from strlcpy() and requires error handling in all its users even when they don't care about truncation. In addition, the implementation can actully be simplified by making it behave properly in strlcpy() style. * Update kernfs_path_from_node_locked() to always fill up the buffer with path. If the buffer is not large enough, the output is truncated and terminated. * kernfs_path() no longer needs error handling. Make it a simple inline wrapper around kernfs_path_from_node(). * sysfs_warn_dup()'s use of kernfs_path() doesn't need error handling. Updated accordingly. * cgroup_path()'s use of kernfs_path() updated to retain the old behavior. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
2016-06-10vfs: make the string hashes salt the hashLinus Torvalds
We always mixed in the parent pointer into the dentry name hash, but we did it late at lookup time. It turns out that we can simplify that lookup-time action by salting the hash with the parent pointer early instead of late. A few other users of our string hashes also wanted to mix in their own pointers into the hash, and those are updated to use the same mechanism. Hash users that don't have any particular initial salt can just use the NULL pointer as a no-salt. Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20Merge tag 'driver-core-4.7-rc1' of ↵Linus Torvalds
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() ...
2016-05-17Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull parallel filesystem directory handling update from Al Viro. This is the main parallel directory work by Al that makes the vfs layer able to do lookup and readdir in parallel within a single directory. That's a big change, since this used to be all protected by the directory inode mutex. The inode mutex is replaced by an rwsem, and serialization of lookups of a single name is done by a "in-progress" dentry marker. The series begins with xattr cleanups, and then ends with switching filesystems over to actually doing the readdir in parallel (switching to the "iterate_shared()" that only takes the read lock). A more detailed explanation of the process from Al Viro: "The xattr work starts with some acl fixes, then switches ->getxattr to passing inode and dentry separately. This is the point where the things start to get tricky - that got merged into the very beginning of the -rc3-based #work.lookups, to allow untangling the security_d_instantiate() mess. The xattr work itself proceeds to switch a lot of filesystems to generic_...xattr(); no complications there. After that initial xattr work, the series then does the following: - untangle security_d_instantiate() - convert a bunch of open-coded lookup_one_len_unlocked() to calls of that thing; one such place (in overlayfs) actually yields a trivial conflict with overlayfs fixes later in the cycle - overlayfs ended up switching to a variant of lookup_one_len_unlocked() sans the permission checks. I would've dropped that commit (it gets overridden on merge from #ovl-fixes in #for-next; proper resolution is to use the variant in mainline fs/overlayfs/super.c), but I didn't want to rebase the damn thing - it was fairly late in the cycle... - some filesystems had managed to depend on lookup/lookup exclusion for *fs-internal* data structures in a way that would break if we relaxed the VFS exclusion. Fixing hadn't been hard, fortunately. - core of that series - parallel lookup machinery, replacing ->i_mutex with rwsem, making lookup_slow() take it only shared. At that point lookups happen in parallel; lookups on the same name wait for the in-progress one to be done with that dentry. Surprisingly little code, at that - almost all of it is in fs/dcache.c, with fs/namei.c changes limited to lookup_slow() - making it use the new primitive and actually switching to locking shared. - parallel readdir stuff - first of all, we provide the exclusion on per-struct file basis, same as we do for read() vs lseek() for regular files. That takes care of most of the needed exclusion in readdir/readdir; however, these guys are trickier than lookups, so I went for switching them one-by-one. To do that, a new method '->iterate_shared()' is added and filesystems are switched to it as they are either confirmed to be OK with shared lock on directory or fixed to be OK with that. I hope to kill the original method come next cycle (almost all in-tree filesystems are switched already), but it's still not quite finished. - several filesystems get switched to parallel readdir. The interesting part here is dealing with dcache preseeding by readdir; that needs minor adjustment to be safe with directory locked only shared. Most of the filesystems doing that got switched to in those commits. Important exception: NFS. Turns out that NFS folks, with their, er, insistence on VFS getting the fuck out of the way of the Smart Filesystem Code That Knows How And What To Lock(tm) have grown the locking of their own. They had their own homegrown rwsem, with lookup/readdir/atomic_open being *writers* (sillyunlink is the reader there). Of course, with VFS getting the fuck out of the way, as requested, the actual smarts of the smart filesystem code etc. had become exposed... - do_last/lookup_open/atomic_open cleanups. As the result, open() without O_CREAT locks the directory only shared. Including the ->atomic_open() case. Backmerge from #for-linus in the middle of that - atomic_open() fix got brought in. - then comes NFS switch to saner (VFS-based ;-) locking, killing the homegrown "lookup and readdir are writers" kinda-sorta rwsem. All exclusion for sillyunlink/lookup is done by the parallel lookups mechanism. Exclusion between sillyunlink and rmdir is a real rwsem now - rmdir being the writer. Result: NFS lookups/readdirs/O_CREAT-less opens happen in parallel now. - the rest of the series consists of switching a lot of filesystems to parallel readdir; in a lot of cases ->llseek() gets simplified as well. One backmerge in there (again, #for-linus - rockridge fix)" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (74 commits) ext4: switch to ->iterate_shared() hfs: switch to ->iterate_shared() hfsplus: switch to ->iterate_shared() hostfs: switch to ->iterate_shared() hpfs: switch to ->iterate_shared() hpfs: handle allocation failures in hpfs_add_pos() gfs2: switch to ->iterate_shared() f2fs: switch to ->iterate_shared() afs: switch to ->iterate_shared() befs: switch to ->iterate_shared() befs: constify stuff a bit isofs: switch to ->iterate_shared() get_acorn_filename(): deobfuscate a bit btrfs: switch to ->iterate_shared() logfs: no need to lock directory in lseek switch ecryptfs to ->iterate_shared 9p: switch to ->iterate_shared() fat: switch to ->iterate_shared() romfs, squashfs: switch to ->iterate_shared() more trivial ->iterate_shared conversions ...
2016-05-09kernfs: no point locking directory around that generic_file_llseek()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-02kernfs_path_from_node_locked: don't overwrite nlenSerge Hallyn
We've calculated @len to be the bytes we need for '/..' entries from @kn_from to the common ancestor, and calculated @nlen to be the extra bytes we need to get from the common ancestor to @kn_to. We use them as such at the end. But in the loop copying the actual entries, we overwrite @nlen. Use a temporary variable for that instead. Without this, the return length, when the buffer is large enough, is wrong. (When the buffer is NULL or too small, the returned value is correct. The buffer contents are also correct.) Interestingly, no callers of this function are affected by this as of yet. However the upcoming cgroup_show_path() will be. Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
2016-03-29fs: kernfs: Replace CURRENT_TIME by current_fs_time()Deepa Dinamani
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>
2016-03-21Merge branch 'for-4.6-ns' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup namespace support from Tejun Heo: "These are changes to implement namespace support for cgroup which has been pending for quite some time now. It is very straight-forward and only affects what part of cgroup hierarchies are visible. After unsharing, mounting a cgroup fs will be scoped to the cgroups the task belonged to at the time of unsharing and the cgroup paths exposed to userland would be adjusted accordingly" * 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: fix and restructure error handling in copy_cgroup_ns() cgroup: fix alloc_cgroup_ns() error handling in copy_cgroup_ns() Add FS_USERNS_FLAG to cgroup fs cgroup: Add documentation for cgroup namespaces cgroup: mount cgroupns-root when inside non-init cgroupns kernfs: define kernfs_node_dentry cgroup: cgroup namespace setns support cgroup: introduce cgroup namespaces sched: new clone flag CLONE_NEWCGROUP for cgroup namespace kernfs: Add API to generate relative kernfs path
2016-02-16kernfs: Add API to generate relative kernfs pathAditya Kali
The new function kernfs_path_from_node() generates and returns kernfs path of a given kernfs_node relative to a given parent kernfs_node. Signed-off-by: Aditya Kali <adityakali@google.com> Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2016-02-07kernfs: make kernfs_walk_ns() use kernfs_pr_cont_buf[]Tejun Heo
kernfs_walk_ns() uses a static path_buf[PATH_MAX] to separate out path components. Keeping around the 4k buffer just for kernfs_walk_ns() is wasteful. This patch makes it piggyback on kernfs_pr_cont_buf[] instead. This requires kernfs_walk_ns() to hold kernfs_rename_lock. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-22wrappers for ->i_mutex accessAl Viro
parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested}, inode_foo(inode) being mutex_foo(&inode->i_mutex). Please, use those for access to ->i_mutex; over the coming cycle ->i_mutex will become rwsem, with ->lookup() done with it held only shared. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-01-14Revert "kernfs: do not account ino_ida allocations to memcg"Vladimir Davydov
Currently, all kmem allocations (namely every kmem_cache_alloc, kmalloc, alloc_kmem_pages call) are accounted to memory cgroup automatically. Callers have to explicitly opt out if they don't want/need accounting for some reason. Such a design decision leads to several problems: - kmalloc users are highly sensitive to failures, many of them implicitly rely on the fact that kmalloc never fails, while memcg makes failures quite plausible. - A lot of objects are shared among different containers by design. Accounting such objects to one of containers is just unfair. Moreover, it might lead to pinning a dead memcg along with its kmem caches, which aren't tiny, which might result in noticeable increase in memory consumption for no apparent reason in the long run. - There are tons of short-lived objects. Accounting them to memcg will only result in slight noise and won't change the overall picture, but we still have to pay accounting overhead. For more info, see - http://lkml.kernel.org/r/20151105144002.GB15111%40dhcp22.suse.cz - http://lkml.kernel.org/r/20151106090555.GK29259@esperanza Therefore this patchset switches to the white list policy. Now kmalloc users have to explicitly opt in by passing __GFP_ACCOUNT flag. Currently, the list of accounted objects is quite limited and only includes those allocations that (1) are known to be easily triggered from userspace and (2) can fail gracefully (for the full list see patch no. 6) and it still misses many object types. However, accounting only those objects should be a satisfactory approximation of the behavior we used to have for most sane workloads. This patch (of 6): Revert 499611ed451508a42d1d7d ("kernfs: do not account ino_ida allocations to memcg"). Black-list kmem accounting policy (aka __GFP_NOACCOUNT) turned out to be fragile and difficult to maintain, because there seem to be many more allocations that should not be accounted than those that should be. Besides, false accounting an allocation might result in much worse consequences than not accounting at all, namely increased memory consumption due to pinned dead kmem caches. So it was decided to switch to the white-list policy. This patch reverts bits introducing the black-list policy. The white-list policy will be introduced later in the series. Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Greg Thelen <gthelen@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-20kernfs: implement kernfs_walk_and_get()Tejun Heo
Implement kernfs_walk_and_get() which is similar to kernfs_find_and_get() but can walk a path instead of just a name. v2: Use strlcpy() instead of strlen() + memcpy() as suggested by David. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: David Miller <davem@davemloft.net>
2015-08-18kernfs: implement kernfs_path_len()Tejun Heo
Add a function to determine the path length of a kernfs node. This for now will be used by writeback tracepoint updates. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-03Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull user namespace updates from Eric Biederman: "Long ago and far away when user namespaces where young it was realized that allowing fresh mounts of proc and sysfs with only user namespace permissions could violate the basic rule that only root gets to decide if proc or sysfs should be mounted at all. Some hacks were put in place to reduce the worst of the damage could be done, and the common sense rule was adopted that fresh mounts of proc and sysfs should allow no more than bind mounts of proc and sysfs. Unfortunately that rule has not been fully enforced. There are two kinds of gaps in that enforcement. Only filesystems mounted on empty directories of proc and sysfs should be ignored but the test for empty directories was insufficient. So in my tree directories on proc, sysctl and sysfs that will always be empty are created specially. Every other technique is imperfect as an ordinary directory can have entries added even after a readdir returns and shows that the directory is empty. Special creation of directories for mount points makes the code in the kernel a smidge clearer about it's purpose. I asked container developers from the various container projects to help test this and no holes were found in the set of mount points on proc and sysfs that are created specially. This set of changes also starts enforcing the mount flags of fresh mounts of proc and sysfs are consistent with the existing mount of proc and sysfs. I expected this to be the boring part of the work but unfortunately unprivileged userspace winds up mounting fresh copies of proc and sysfs with noexec and nosuid clear when root set those flags on the previous mount of proc and sysfs. So for now only the atime, read-only and nodev attributes which userspace happens to keep consistent are enforced. Dealing with the noexec and nosuid attributes remains for another time. This set of changes also addresses an issue with how open file descriptors from /proc/<pid>/ns/* are displayed. Recently readlink of /proc/<pid>/fd has been triggering a WARN_ON that has not been meaningful since it was added (as all of the code in the kernel was converted) and is not now actively wrong. There is also a short list of issues that have not been fixed yet that I will mention briefly. It is possible to rename a directory from below to above a bind mount. At which point any directory pointers below the renamed directory can be walked up to the root directory of the filesystem. With user namespaces enabled a bind mount of the bind mount can be created allowing the user to pick a directory whose children they can rename to outside of the bind mount. This is challenging to fix and doubly so because all obvious solutions must touch code that is in the performance part of pathname resolution. As mentioned above there is also a question of how to ensure that developers by accident or with purpose do not introduce exectuable files on sysfs and proc and in doing so introduce security regressions in the current userspace that will not be immediately obvious and as such are likely to require breaking userspace in painful ways once they are recognized" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: vfs: Remove incorrect debugging WARN in prepend_path mnt: Update fs_fully_visible to test for permanently empty directories sysfs: Create mountpoints with sysfs_create_mount_point sysfs: Add support for permanently empty directories to serve as mount points. kernfs: Add support for always empty directories. proc: Allow creating permanently empty directories that serve as mount points sysctl: Allow creating permanently empty directories that serve as mountpoints. fs: Add helper functions for permanently empty directories. vfs: Ignore unlocked mounts in fs_fully_visible mnt: Modify fs_fully_visible to deal with locked ro nodev and atime mnt: Refactor the logic for mounting sysfs and proc in a user namespace