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* proc: faster open/read/close with "permanent" filesAlexey Dobriyan2020-04-071-3/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that "struct proc_ops" exist we can start putting there stuff which could not fly with VFS "struct file_operations"... Most of fs/proc/inode.c file is dedicated to make open/read/.../close reliable in the event of disappearing /proc entries which usually happens if module is getting removed. Files like /proc/cpuinfo which never disappear simply do not need such protection. Save 2 atomic ops, 1 allocation, 1 free per open/read/close sequence for such "permanent" files. Enable "permanent" flag for /proc/cpuinfo /proc/kmsg /proc/modules /proc/slabinfo /proc/stat /proc/sysvipc/* /proc/swaps More will come once I figure out foolproof way to prevent out module authors from marking their stuff "permanent" for performance reasons when it is not. This should help with scalability: benchmark is "read /proc/cpuinfo R times by N threads scattered over the system". N R t, s (before) t, s (after) ----------------------------------------------------- 64 4096 1.582458 1.530502 -3.2% 256 4096 6.371926 6.125168 -3.9% 1024 4096 25.64888 24.47528 -4.6% Benchmark source: #include <chrono> #include <iostream> #include <thread> #include <vector> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> const int NR_CPUS = sysconf(_SC_NPROCESSORS_ONLN); int N; const char *filename; int R; int xxx = 0; int glue(int n) { cpu_set_t m; CPU_ZERO(&m); CPU_SET(n, &m); return sched_setaffinity(0, sizeof(cpu_set_t), &m); } void f(int n) { glue(n % NR_CPUS); while (*(volatile int *)&xxx == 0) { } for (int i = 0; i < R; i++) { int fd = open(filename, O_RDONLY); char buf[4096]; ssize_t rv = read(fd, buf, sizeof(buf)); asm volatile ("" :: "g" (rv)); close(fd); } } int main(int argc, char *argv[]) { if (argc < 4) { std::cerr << "usage: " << argv[0] << ' ' << "N /proc/filename R "; return 1; } N = atoi(argv[1]); filename = argv[2]; R = atoi(argv[3]); for (int i = 0; i < NR_CPUS; i++) { if (glue(i) == 0) break; } std::vector<std::thread> T; T.reserve(N); for (int i = 0; i < N; i++) { T.emplace_back(f, i); } auto t0 = std::chrono::system_clock::now(); { *(volatile int *)&xxx = 1; for (auto& t: T) { t.join(); } } auto t1 = std::chrono::system_clock::now(); std::chrono::duration<double> dt = t1 - t0; std::cout << dt.count() << ' '; return 0; } P.S.: Explicit randomization marker is added because adding non-function pointer will silently disable structure layout randomization. [akpm@linux-foundation.org: coding style fixes] Reported-by: kbuild test robot <lkp@intel.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Joe Perches <joe@perches.com> Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: decouple proc from VFS with "struct proc_ops"Alexey Dobriyan2020-02-041-20/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently core /proc code uses "struct file_operations" for custom hooks, however, VFS doesn't directly call them. Every time VFS expands file_operations hook set, /proc code bloats for no reason. Introduce "struct proc_ops" which contains only those hooks which /proc allows to call into (open, release, read, write, ioctl, mmap, poll). It doesn't contain module pointer as well. Save ~184 bytes per usage: add/remove: 26/26 grow/shrink: 1/4 up/down: 1922/-6674 (-4752) Function old new delta sysvipc_proc_ops - 72 +72 ... config_gz_proc_ops - 72 +72 proc_get_inode 289 339 +50 proc_reg_get_unmapped_area 110 107 -3 close_pdeo 227 224 -3 proc_reg_open 289 284 -5 proc_create_data 60 53 -7 rt_cpu_seq_fops 256 - -256 ... default_affinity_proc_fops 256 - -256 Total: Before=5430095, After=5425343, chg -0.09% Link: http://lkml.kernel.org/r/20191225172228.GA13378@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs/proc/generic.c: delete useless "len" variableAlexey Dobriyan2019-12-041-4/+2
| | | | | | | | | | | Pointer to next '/' encodes length of path element and next start position. Subtraction and increment are redundant. Link: http://lkml.kernel.org/r/20191004234521.GA30246@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: change ->nlink under proc_subdir_lockAlexey Dobriyan2019-12-041-16/+15
| | | | | | | | | | | | Currently gluing PDE into global /proc tree is done under lock, but changing ->nlink is not. Additionally struct proc_dir_entry::nlink is not atomic so updates can be lost. Link: http://lkml.kernel.org/r/20190925202436.GA17388@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* treewide: Add SPDX license identifier for missed filesThomas Gleixner2019-05-211-0/+1
| | | | | | | | | | | | | | | | | Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* proc: fix /proc/net/* after setns(2)Alexey Dobriyan2019-02-011-1/+3
| | | | | | | | | | | | | | | | | | /proc entries under /proc/net/* can't be cached into dcache because setns(2) can change current net namespace. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: avoid vim miscolorization] [adobriyan@gmail.com: write test, add dummy ->d_revalidate hook: necessary if /proc/net/* is pinned at setns time] Link: http://lkml.kernel.org/r/20190108192350.GA12034@avx2 Link: http://lkml.kernel.org/r/20190107162336.GA9239@avx2 Fixes: 1da4d377f943fe4194ffb9fb9c26cc58fad4dd24 ("proc: revalidate misc dentries") Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reported-by: Mateusz Stępień <mateusz.stepien@netrounds.com> Reported-by: Ahmad Fatoum <a.fatoum@pengutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: smaller readlock section in readdir("/proc")Alexey Dobriyan2018-08-221-2/+2
| | | | | | | | | | | Readdir context is thread local, so ->pos is thread local, move it out of readlock. Link: http://lkml.kernel.org/r/20180627195339.GD18113@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: add proc_seq_releaseChunyu Hu2018-06-271-1/+10
| | | | | | | | | | | | | | | | | | kmemleak reported some memory leak on reading proc files. After adding some debug lines, find that proc_seq_fops is using seq_release as release handler, which won't handle the free of 'private' field of seq_file, while in fact the open handler proc_seq_open could create the private data with __seq_open_private when state_size is greater than zero. So after reading files created with proc_create_seq_private, such as /proc/timer_list and /proc/vmallocinfo, the private mem of a seq_file is not freed. Fix it by adding the paired proc_seq_release as the default release handler of proc_seq_ops instead of seq_release. Fixes: 44414d82cfe0 ("proc: introduce proc_create_seq_private") Reviewed-by: Christoph Hellwig <hch@lst.de> CC: Christoph Hellwig <hch@lst.de> Signed-off-by: Chunyu Hu <chuhu@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'afs-proc' of ↵Linus Torvalds2018-06-161-1/+25
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull AFS updates from Al Viro: "Assorted AFS stuff - ended up in vfs.git since most of that consists of David's AFS-related followups to Christoph's procfs series" * 'afs-proc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: afs: Optimise callback breaking by not repeating volume lookup afs: Display manually added cells in dynamic root mount afs: Enable IPv6 DNS lookups afs: Show all of a server's addresses in /proc/fs/afs/servers afs: Handle CONFIG_PROC_FS=n proc: Make inline name size calculation automatic afs: Implement network namespacing afs: Mark afs_net::ws_cell as __rcu and set using rcu functions afs: Fix a Sparse warning in xdr_decode_AFSFetchStatus() proc: Add a way to make network proc files writable afs: Rearrange fs/afs/proc.c to remove remaining predeclarations. afs: Rearrange fs/afs/proc.c to move the show routines up afs: Rearrange fs/afs/proc.c by moving fops and open functions down afs: Move /proc management functions to the end of the file
| * proc: Make inline name size calculation automaticDavid Howells2018-06-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Make calculation of the size of the inline name in struct proc_dir_entry automatic, rather than having to manually encode the numbers and failing to allow for lockdep. Require a minimum inline name size of 33+1 to allow for names that look like two hex numbers with a dash between. Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * proc: Add a way to make network proc files writableDavid Howells2018-05-181-0/+24
| | | | | | | | | | | | | | | | | | | | | | | | Provide two extra functions, proc_create_net_data_write() and proc_create_net_single_write() that act like their non-write versions but also set a write method in the proc_dir_entry struct. An internal simple write function is provided that will copy its buffer and hand it to the pde->write() method if available (or give an error if not). The buffer may be modified by the write method. Signed-off-by: David Howells <dhowells@redhat.com>
* | Merge branch 'work.lookup' of ↵Linus Torvalds2018-06-041-2/+1
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull dcache lookup cleanups from Al Viro: "Cleaning ->lookup() instances up - mostly d_splice_alias() conversions" * 'work.lookup' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (29 commits) switch the rest of procfs lookups to d_splice_alias() procfs: switch instantiate_t to d_splice_alias() don't bother with tid_fd_revalidate() in lookups proc_lookupfd_common(): don't bother with instantiate unless the file is open procfs: get rid of ancient BS in pid_revalidate() uses cifs_lookup(): switch to d_splice_alias() cifs_lookup(): cifs_get_inode_...() never returns 0 with *inode left NULL 9p: unify paths in v9fs_vfs_lookup() ncp_lookup(): use d_splice_alias() hfsplus: switch to d_splice_alias() hfs: don't allow mounting over .../rsrc hfs: use d_splice_alias() omfs_lookup(): report IO errors, use d_splice_alias() orangefs_lookup: simplify openpromfs: switch to d_splice_alias() xfs_vn_lookup: simplify a bit adfs_lookup: do not fail with ENOENT on negatives, use d_splice_alias() adfs_lookup_byname: .. *is* taken care of in fs/namei.c romfs_lookup: switch to d_splice_alias() qnx6_lookup: switch to d_splice_alias() ...
| * switch the rest of procfs lookups to d_splice_alias()Al Viro2018-05-261-2/+1
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | proc: introduce proc_create_single{,_data}Christoph Hellwig2018-05-161-0/+29
| | | | | | | | | | | | | | | | | | Variants of proc_create{,_data} that directly take a seq_file show callback and drastically reduces the boilerplate code in the callers. All trivial callers converted over. Signed-off-by: Christoph Hellwig <hch@lst.de>
* | proc: introduce proc_create_seq_privateChristoph Hellwig2018-05-161-3/+6
| | | | | | | | | | | | | | | | | | | | Variant of proc_create_data that directly take a struct seq_operations argument + a private state size and drastically reduces the boilerplate code in the callers. All trivial callers converted over. Signed-off-by: Christoph Hellwig <hch@lst.de>
* | proc: introduce proc_create_seq{,_data}Christoph Hellwig2018-05-161-0/+30
| | | | | | | | | | | | | | | | | | Variants of proc_create{,_data} that directly take a struct seq_operations argument and drastically reduces the boilerplate code in the callers. All trivial callers converted over. Signed-off-by: Christoph Hellwig <hch@lst.de>
* | proc: add a proc_create_reg helperChristoph Hellwig2018-05-161-19/+25
| | | | | | | | | | | | | | Common code for creating a regular file. Factor out of proc_create_data, to be reused by other functions soon. Signed-off-by: Christoph Hellwig <hch@lst.de>
* | proc: simplify proc_register calling conventionsChristoph Hellwig2018-05-161-26/+18
|/ | | | | | | | Return registered entry on success, return NULL on failure and free the passed in entry. Also expose it in internal.h as we'll start using it in proc_net.c soon. Signed-off-by: Christoph Hellwig <hch@lst.de>
* proc: revalidate misc dentriesAlexey Dobriyan2018-04-131-1/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If module removes proc directory while another process pins it by chdir'ing to it, then subsequent recreation of proc entry and all entries down the tree will not be visible to any process until pinning process unchdir from directory and unpins everything. Steps to reproduce: proc_mkdir("aaa", NULL); proc_create("aaa/bbb", ...); chdir("/proc/aaa"); remove_proc_entry("aaa/bbb", NULL); remove_proc_entry("aaa", NULL); proc_mkdir("aaa", NULL); # inaccessible because "aaa" dentry still points # to the original "aaa". proc_create("aaa/bbb", ...); Fix is to implement ->d_revalidate and ->d_delete. Link: http://lkml.kernel.org/r/20180312201938.GA4871@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: use slower rb_first()Alexey Dobriyan2018-04-111-14/+12
| | | | | | | | | | | | | | | | | | | | | | In a typical for /proc "open+read+close" usecase, dentry is looked up successfully on open only to be killed in dput() on close. In fact dentries which aren't /proc/*/... and /proc/sys/* were almost NEVER CACHED. Simple printk in proc_lookup_de() shows that. Now that ->delete hook intelligently picks which dentries should live in dcache and which should not, rbtree caching is not necessary as dcache does it job, at last! As a side effect, struct proc_dir_entry shrinks by one pointer which can go into inline name. Link: http://lkml.kernel.org/r/20180314231032.GA15854@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Davidlohr Bueso <dbueso@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: switch struct proc_dir_entry::count to refcountAlexey Dobriyan2018-04-111-2/+2
| | | | | | | | | ->count is honest reference count unlike ->in_use. Link: http://lkml.kernel.org/r/20180313174550.GA4332@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: reject "." and ".." as filenamesAlexey Dobriyan2018-04-111-0/+8
| | | | | | | | | | | | | | | | | | | Various subsystems can create files and directories in /proc with names directly controlled by userspace. Which means "/", "." and ".." are no-no. "/" split is already taken care of, do the other 2 prohibited names. Link: http://lkml.kernel.org/r/20180310001223.GB12443@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Florian Westphal <fw@strlen.de> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: move "struct proc_dir_entry" into kmem cacheAlexey Dobriyan2018-04-111-18/+32
| | | | | | | | | | | | | | | | | | | | | "struct proc_dir_entry" is variable sized because of 0-length trailing array for name, however, because of SLAB padding allocations it is possible to make "struct proc_dir_entry" fixed sized and allocate same amount of memory. It buys fine-grained debugging with poisoning and usercopy protection which is not possible with kmalloc-* caches. Currently, on 32-bit 91+ byte allocations go into kmalloc-128 and on 64-bit 147+ byte allocations go to kmalloc-192 anyway. Additional memory is allocated only for 38/46+ byte long names which are rare or may not even exist in the wild. Link: http://lkml.kernel.org/r/20180223205504.GA17139@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: rearrange argsAlexey Dobriyan2018-02-061-9/+9
| | | | | | | | | | | | | | | | | | | | | | | | Rearrange args for smaller code. lookup revolves around memcmp() which gets len 3rd arg, so propagate length as 3rd arg. readdir and lookup add additional arg to VFS ->readdir and ->lookup, so better add it to the end. Space savings on x86_64: add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-18 (-18) Function old new delta proc_readdir 22 13 -9 proc_lookup 18 9 -9 proc_match() is smaller if not inlined, I promise! Link: http://lkml.kernel.org/r/20180104175958.GB5204@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* procfs: use faster rb_first_cached()Davidlohr Bueso2017-09-081-12/+14
| | | | | | | | | | | | | ... such that we can avoid the tree walks to get the node with the smallest key. Semantically the same, as the previously used rb_first(), but O(1). The main overhead is the extra footprint for the cached rb_node pointer, which should not matter for procfs. Link: http://lkml.kernel.org/r/20170719014603.19029-14-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: uninline proc_create()Alexey Dobriyan2017-09-081-0/+8
| | | | | | | | | | | | | | | | | | | | | Save some code from ~320 invocations all clearing last argument. add/remove: 3/0 grow/shrink: 0/158 up/down: 45/-702 (-657) function old new delta proc_create - 17 +17 __ksymtab_proc_create - 16 +16 __kstrtab_proc_create - 12 +12 yam_init_driver 301 298 -3 ... cifs_proc_init 249 228 -21 via_fb_pci_probe 2304 2280 -24 Link: http://lkml.kernel.org/r/20170819094702.GA27864@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs/proc/generic.c: switch to ida_simple_get/removeHeiner Kallweit2017-07-101-25/+7
| | | | | | | | | | The code can be much simplified by switching to ida_simple_get/remove. Link: http://lkml.kernel.org/r/8d1cc9f7-5115-c9dc-028e-c0770b6bfe1f@gmail.com Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: Fix unbalanced hard link numbersTakashi Iwai2017-04-281-0/+1
| | | | | | | | | | | | proc_create_mount_point() forgot to increase the parent's nlink, and it resulted in unbalanced hard link numbers, e.g. /proc/fs shows one less than expected. Fixes: eb6d38d5427b ("proc: Allow creating permanently empty directories...") Cc: stable@vger.kernel.org Reported-by: Tristan Ye <tristan.ye@suse.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* statx: Add a system call to make enhanced file info availableDavid Howells2017-03-021-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a system call to make extended file information available, including file creation and some attribute flags where available through the underlying filesystem. The getattr inode operation is altered to take two additional arguments: a u32 request_mask and an unsigned int flags that indicate the synchronisation mode. This change is propagated to the vfs_getattr*() function. Functions like vfs_stat() are now inline wrappers around new functions vfs_statx() and vfs_statx_fd() to reduce stack usage. ======== OVERVIEW ======== The idea was initially proposed as a set of xattrs that could be retrieved with getxattr(), but the general preference proved to be for a new syscall with an extended stat structure. A number of requests were gathered for features to be included. The following have been included: (1) Make the fields a consistent size on all arches and make them large. (2) Spare space, request flags and information flags are provided for future expansion. (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an __s64). (4) Creation time: The SMB protocol carries the creation time, which could be exported by Samba, which will in turn help CIFS make use of FS-Cache as that can be used for coherency data (stx_btime). This is also specified in NFSv4 as a recommended attribute and could be exported by NFSD [Steve French]. (5) Lightweight stat: Ask for just those details of interest, and allow a netfs (such as NFS) to approximate anything not of interest, possibly without going to the server [Trond Myklebust, Ulrich Drepper, Andreas Dilger] (AT_STATX_DONT_SYNC). (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks its cached attributes are up to date [Trond Myklebust] (AT_STATX_FORCE_SYNC). And the following have been left out for future extension: (7) Data version number: Could be used by userspace NFS servers [Aneesh Kumar]. Can also be used to modify fill_post_wcc() in NFSD which retrieves i_version directly, but has just called vfs_getattr(). It could get it from the kstat struct if it used vfs_xgetattr() instead. (There's disagreement on the exact semantics of a single field, since not all filesystems do this the same way). (8) BSD stat compatibility: Including more fields from the BSD stat such as creation time (st_btime) and inode generation number (st_gen) [Jeremy Allison, Bernd Schubert]. (9) Inode generation number: Useful for FUSE and userspace NFS servers [Bernd Schubert]. (This was asked for but later deemed unnecessary with the open-by-handle capability available and caused disagreement as to whether it's a security hole or not). (10) Extra coherency data may be useful in making backups [Andreas Dilger]. (No particular data were offered, but things like last backup timestamp, the data version number and the DOS archive bit would come into this category). (11) Allow the filesystem to indicate what it can/cannot provide: A filesystem can now say it doesn't support a standard stat feature if that isn't available, so if, for instance, inode numbers or UIDs don't exist or are fabricated locally... (This requires a separate system call - I have an fsinfo() call idea for this). (12) Store a 16-byte volume ID in the superblock that can be returned in struct xstat [Steve French]. (Deferred to fsinfo). (13) Include granularity fields in the time data to indicate the granularity of each of the times (NFSv4 time_delta) [Steve French]. (Deferred to fsinfo). (14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags. Note that the Linux IOC flags are a mess and filesystems such as Ext4 define flags that aren't in linux/fs.h, so translation in the kernel may be a necessity (or, possibly, we provide the filesystem type too). (Some attributes are made available in stx_attributes, but the general feeling was that the IOC flags were to ext[234]-specific and shouldn't be exposed through statx this way). (15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer, Michael Kerrisk]. (Deferred, probably to fsinfo. Finding out if there's an ACL or seclabal might require extra filesystem operations). (16) Femtosecond-resolution timestamps [Dave Chinner]. (A __reserved field has been left in the statx_timestamp struct for this - if there proves to be a need). (17) A set multiple attributes syscall to go with this. =============== NEW SYSTEM CALL =============== The new system call is: int ret = statx(int dfd, const char *filename, unsigned int flags, unsigned int mask, struct statx *buffer); The dfd, filename and flags parameters indicate the file to query, in a similar way to fstatat(). There is no equivalent of lstat() as that can be emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is also no equivalent of fstat() as that can be emulated by passing a NULL filename to statx() with the fd of interest in dfd. Whether or not statx() synchronises the attributes with the backing store can be controlled by OR'ing a value into the flags argument (this typically only affects network filesystems): (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this respect. (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise its attributes with the server - which might require data writeback to occur to get the timestamps correct. (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a network filesystem. The resulting values should be considered approximate. mask is a bitmask indicating the fields in struct statx that are of interest to the caller. The user should set this to STATX_BASIC_STATS to get the basic set returned by stat(). It should be noted that asking for more information may entail extra I/O operations. buffer points to the destination for the data. This must be 256 bytes in size. ====================== MAIN ATTRIBUTES RECORD ====================== The following structures are defined in which to return the main attribute set: struct statx_timestamp { __s64 tv_sec; __s32 tv_nsec; __s32 __reserved; }; struct statx { __u32 stx_mask; __u32 stx_blksize; __u64 stx_attributes; __u32 stx_nlink; __u32 stx_uid; __u32 stx_gid; __u16 stx_mode; __u16 __spare0[1]; __u64 stx_ino; __u64 stx_size; __u64 stx_blocks; __u64 __spare1[1]; struct statx_timestamp stx_atime; struct statx_timestamp stx_btime; struct statx_timestamp stx_ctime; struct statx_timestamp stx_mtime; __u32 stx_rdev_major; __u32 stx_rdev_minor; __u32 stx_dev_major; __u32 stx_dev_minor; __u64 __spare2[14]; }; The defined bits in request_mask and stx_mask are: STATX_TYPE Want/got stx_mode & S_IFMT STATX_MODE Want/got stx_mode & ~S_IFMT STATX_NLINK Want/got stx_nlink STATX_UID Want/got stx_uid STATX_GID Want/got stx_gid STATX_ATIME Want/got stx_atime{,_ns} STATX_MTIME Want/got stx_mtime{,_ns} STATX_CTIME Want/got stx_ctime{,_ns} STATX_INO Want/got stx_ino STATX_SIZE Want/got stx_size STATX_BLOCKS Want/got stx_blocks STATX_BASIC_STATS [The stuff in the normal stat struct] STATX_BTIME Want/got stx_btime{,_ns} STATX_ALL [All currently available stuff] stx_btime is the file creation time, stx_mask is a bitmask indicating the data provided and __spares*[] are where as-yet undefined fields can be placed. Time fields are structures with separate seconds and nanoseconds fields plus a reserved field in case we want to add even finer resolution. Note that times will be negative if before 1970; in such a case, the nanosecond fields will also be negative if not zero. The bits defined in the stx_attributes field convey information about a file, how it is accessed, where it is and what it does. The following attributes map to FS_*_FL flags and are the same numerical value: STATX_ATTR_COMPRESSED File is compressed by the fs STATX_ATTR_IMMUTABLE File is marked immutable STATX_ATTR_APPEND File is append-only STATX_ATTR_NODUMP File is not to be dumped STATX_ATTR_ENCRYPTED File requires key to decrypt in fs Within the kernel, the supported flags are listed by: KSTAT_ATTR_FS_IOC_FLAGS [Are any other IOC flags of sufficient general interest to be exposed through this interface?] New flags include: STATX_ATTR_AUTOMOUNT Object is an automount trigger These are for the use of GUI tools that might want to mark files specially, depending on what they are. Fields in struct statx come in a number of classes: (0) stx_dev_*, stx_blksize. These are local system information and are always available. (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino, stx_size, stx_blocks. These will be returned whether the caller asks for them or not. The corresponding bits in stx_mask will be set to indicate whether they actually have valid values. If the caller didn't ask for them, then they may be approximated. For example, NFS won't waste any time updating them from the server, unless as a byproduct of updating something requested. If the values don't actually exist for the underlying object (such as UID or GID on a DOS file), then the bit won't be set in the stx_mask, even if the caller asked for the value. In such a case, the returned value will be a fabrication. Note that there are instances where the type might not be valid, for instance Windows reparse points. (2) stx_rdev_*. This will be set only if stx_mode indicates we're looking at a blockdev or a chardev, otherwise will be 0. (3) stx_btime. Similar to (1), except this will be set to 0 if it doesn't exist. ======= TESTING ======= The following test program can be used to test the statx system call: samples/statx/test-statx.c Just compile and run, passing it paths to the files you want to examine. The file is built automatically if CONFIG_SAMPLES is enabled. Here's some example output. Firstly, an NFS directory that crosses to another FSID. Note that the AUTOMOUNT attribute is set because transiting this directory will cause d_automount to be invoked by the VFS. [root@andromeda ~]# /tmp/test-statx -A /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:26 Inode: 1703937 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------) Secondly, the result of automounting on that directory. [root@andromeda ~]# /tmp/test-statx /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:27 Inode: 2 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* proc: use rb_entry()Geliang Tang2017-02-241-5/+6
| | | | | | | | | | | | | | | | To make the code clearer, use rb_entry() instead of container_of() to deal with rbtree. Link: http://lkml.kernel.org/r/4fd1f82818665705ce75c5156a060ae7caa8e0a9.1482160150.git.geliangtang@gmail.com Signed-off-by: Geliang Tang <geliangtang@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "David S. Miller" <davem@davemloft.net> Cc: Juergen Gross <jgross@suse.com> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Replace <asm/uaccess.h> with <linux/uaccess.h> globallyLinus Torvalds2016-12-241-1/+1
| | | | | | | | | | | | | This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* xenfs: Use proc_create_mount_point() to create /proc/xenSeth Forshee2016-11-171-0/+1
| | | | | | | | | | | | | Mounting proc in user namespace containers fails if the xenbus filesystem is mounted on /proc/xen because this directory fails the "permanently empty" test. proc_create_mount_point() exists specifically to create such mountpoints in proc but is currently proc-internal. Export this interface to modules, then use it in xenbus when creating /proc/xen. Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Juergen Gross <jgross@suse.com>
* Merge branch 'work.misc' of ↵Linus Torvalds2016-10-101-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs updates from Al Viro: "Assorted misc bits and pieces. There are several single-topic branches left after this (rename2 series from Miklos, current_time series from Deepa Dinamani, xattr series from Andreas, uaccess stuff from from me) and I'd prefer to send those separately" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (39 commits) proc: switch auxv to use of __mem_open() hpfs: support FIEMAP cifs: get rid of unused arguments of CIFSSMBWrite() posix_acl: uapi header split posix_acl: xattr representation cleanups fs/aio.c: eliminate redundant loads in put_aio_ring_file fs/internal.h: add const to ns_dentry_operations declaration compat: remove compat_printk() fs/buffer.c: make __getblk_slow() static proc: unsigned file descriptors fs/file: more unsigned file descriptors fs: compat: remove redundant check of nr_segs cachefiles: Fix attempt to read i_blocks after deleting file [ver #2] cifs: don't use memcpy() to copy struct iov_iter get rid of separate multipage fault-in primitives fs: Avoid premature clearing of capabilities fs: Give dentry to inode_change_ok() instead of inode fuse: Propagate dentry down to inode_change_ok() ceph: Propagate dentry down to inode_change_ok() xfs: Propagate dentry down to inode_change_ok() ...
| * fs: Give dentry to inode_change_ok() instead of inodeJan Kara2016-09-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | inode_change_ok() will be resposible for clearing capabilities and IMA extended attributes and as such will need dentry. Give it as an argument to inode_change_ok() instead of an inode. Also rename inode_change_ok() to setattr_prepare() to better relect that it does also some modifications in addition to checks. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
* | proc: make proc entries inherit ownership from parentDmitry Torokhov2016-08-141-0/+2
|/ | | | | | | | | | | | There are certain parameters that belong to net namespace and that are exported in /proc. They should be controllable by the container's owner, but are currently owned by global root and thus not available. Let's change proc code to inherit ownership of parent entry, and when create per-ns "net" proc entry set it up as owned by container's owner. Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* switch all procfs directories ->iterate_shared()Al Viro2016-05-021-1/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* proc: change proc_subdir_lock to a rwlockWaiman Long2015-09-101-22/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The proc_subdir_lock spinlock is used to allow only one task to make change to the proc directory structure as well as looking up information in it. However, the information lookup part can actually be entered by more than one task as the pde_get() and pde_put() reference count update calls in the critical sections are atomic increment and decrement respectively and so are safe with concurrent updates. The x86 architecture has already used qrwlock which is fair and other architectures like ARM are in the process of switching to qrwlock. So unfairness shouldn't be a concern in that conversion. This patch changed the proc_subdir_lock to a rwlock in order to enable concurrent lookup. The following functions were modified to take a write lock: - proc_register() - remove_proc_entry() - remove_proc_subtree() The following functions were modified to take a read lock: - xlate_proc_name() - proc_lookup_de() - proc_readdir_de() A parallel /proc filesystem search with the "find" command (1000 threads) was run on a 4-socket Haswell-EX box (144 threads). Before the patch, the parallel search took about 39s. After the patch, the parallel find took only 25s, a saving of about 14s. The micro-benchmark that I used was artificial, but it was used to reproduce an exit hanging problem that I saw in real application. In fact, only allow one task to do a lookup seems too limiting to me. Signed-off-by: Waiman Long <Waiman.Long@hp.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Scott J Norton <scott.norton@hp.com> Cc: Douglas Hatch <doug.hatch@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: Allow creating permanently empty directories that serve as mount pointsEric W. Biederman2015-07-011-0/+23
| | | | | | | | | | | | | | | | | | Add a new function proc_create_mount_point that when used to creates a directory that can not be added to. Add a new function is_empty_pde to test if a function is a mount point. Update the code to use make_empty_dir_inode when reporting a permanently empty directory to the vfs. Update the code to not allow adding to permanently empty directories. Update /proc/openprom and /proc/fs/nfsd to be permanently empty directories. Cc: stable@vger.kernel.org Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* VFS: normal filesystems (and lustre): d_inode() annotationsDavid Howells2015-04-151-2/+2
| | | | | | | that's the bulk of filesystem drivers dealing with inodes of their own Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* procfs: fix race between symlink removals and traversalsAl Viro2015-02-221-12/+0
| | | | | | | use_pde()/unuse_pde() in ->follow_link()/->put_link() resp. Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-linus' of ↵Linus Torvalds2015-02-171-17/+8
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc VFS updates from Al Viro: "This cycle a lot of stuff sits on topical branches, so I'll be sending more or less one pull request per branch. This is the first pile; more to follow in a few. In this one are several misc commits from early in the cycle (before I went for separate branches), plus the rework of mntput/dput ordering on umount, switching to use of fs_pin instead of convoluted games in namespace_unlock()" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: switch the IO-triggering parts of umount to fs_pin new fs_pin killing logics allow attaching fs_pin to a group not associated with some superblock get rid of the second argument of acct_kill() take count and rcu_head out of fs_pin dcache: let the dentry count go down to zero without taking d_lock pull bumping refcount into ->kill() kill pin_put() mode_t whack-a-mole: chelsio file->f_path.dentry is pinned down for as long as the file is open... get rid of lustre_dump_dentry() gut proc_register() a bit kill d_validate() ncpfs: get rid of d_validate() nonsense selinuxfs: don't open-code d_genocide()
| * gut proc_register() a bitAl Viro2015-01-251-17/+8
| | | | | | | | | | | | | | There are only 3 callers and quite a bit of that thing is executed exactly in one of those. Just lift it there... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | fs: proc: use PDE() to get proc_dir_entryAlexander Kuleshov2015-02-121-1/+1
|/ | | | | | | | | Use the PDE() helper to get proc_dir_entry instead of coding it directly. Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com> Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs/proc.c: use rb_entry_safe() instead of rb_entry()Nicolas Dichtel2014-12-101-12/+4
| | | | | | | | Better to use existing macro that rewriting them. Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* procfs: fix error handling of proc_register()Debabrata Banerjee2014-12-101-1/+8
| | | | | | | | | | proc_register() error paths are leaking inodes and directory refcounts. Signed-off-by: Debabrata Banerjee <dbanerje@akamai.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs/proc: use a rb tree for the directory entriesNicolas Dichtel2014-12-101-59/+105
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a lot of netdevices are created, one of the bottleneck is the creation of proc entries. This serie aims to accelerate this part. The current implementation for the directories in /proc is using a single linked list. This is slow when handling directories with large numbers of entries (eg netdevice-related entries when lots of tunnels are opened). This patch replaces this linked list by a red-black tree. Here are some numbers: dummy30000.batch contains 30 000 times 'link add type dummy'. Before the patch: $ time ip -b dummy30000.batch real 2m31.950s user 0m0.440s sys 2m21.440s $ time rmmod dummy real 1m35.764s user 0m0.000s sys 1m24.088s After the patch: $ time ip -b dummy30000.batch real 2m0.874s user 0m0.448s sys 1m49.720s $ time rmmod dummy real 1m13.988s user 0m0.000s sys 1m1.008s The idea of improving this part was suggested by Thierry Herbelot. [akpm@linux-foundation.org: initialise proc_root.subdir at compile time] Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Acked-by: David S. Miller <davem@davemloft.net> Cc: Thierry Herbelot <thierry.herbelot@6wind.com>. Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: make proc_subdir_lock staticAlexey Dobriyan2014-08-081-1/+1
| | | | | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: add and remove /proc entry create checksAlexey Dobriyan2014-08-081-15/+15
| | | | | | | | | | | | | | | | | | | | | | | | | * remove proc_create(NULL, ...) check, let it oops * warn about proc_create("", ...) and proc_create("very very long name", ...) proc code keeps length as u8, no 256+ name length possible * warn about proc_create("123", ...) /proc/$PID and /proc/misc namespaces are separate things, but dumb module might create funky a-la $PID entry. * remove post mortem strchr('/') check Triggering it implies either strchr() is buggy or memory corruption. It should be VFS check anyway. In reality, none of these checks will ever trigger, it is preparation for the next patch. Based on patch from Al Viro. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: set attributes of pde using accessor functionsRui Xiang2014-01-231-2/+1
| | | | | | | | | Use existing accessors proc_set_user() and proc_set_size() to set attributes. Just a cleanup. Signed-off-by: Rui Xiang <rui.xiang@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* consolidate simple ->d_delete() instancesAl Viro2013-11-151-17/+1
| | | | | | | | Rename simple_delete_dentry() to always_delete_dentry() and export it. Export simple_dentry_operations, while we are at it, and get rid of their duplicates Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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