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task_state() needs tasklist_lock to protect ->parent/->real_parent. However
task->parent points to nowhere only when the actions below happen in order
1) release_task(task)
2) release_task(task->parent)
3) a grace period passed
But 3) implies that the memory ops from 1) should be finished, so pid_alive()
can't be true in such a case.
Otherwise, we don't care if ->parent/->real_parent changes under us.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Drop tasklist_lock. ->siglock protects almost all interesting data
(including sub-threads traversal) except:
->signal->tty
protected by tty_mutex
->real_parent
the task can't be unhashed while we are holding
->siglock, so ->real_parent can change from under us
but we can safely dereference it under rcu_read_lock()
->pgrp/->session
we can get inconsistent numbers if the task does
sys_setsid/daemonize at the same time. I hope this
is acceptable.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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lock_task_sighand() can take ->siglock without holding tasklist_lock.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The implementation is exactly the same and there is currently nothing to
distinguish proc_tid_attr, and proc_tgid_attr. So it is pointless to have two
separate implementations.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The hard coded inode numbers in proc currently limit its maintainability,
its flexibility, and what can be done with the rest of system. /proc limits
pid-max to 32768 on 32 bit systems it limits fd-max to 32768 on all systems,
and placing the pid in the inode number really gets in the way of implementing
subdirectories of per process information.
Ever since people started adding to the middle of the file type enumeration we
haven't been maintaing the historical inode numbers, all we have really
succeeded in doing is keeping the pid in the proc inode number. The pid is
already available in the directory name so no information is lost removing it
from the inode number.
So if something in user space cares if we remove the inode number from the
/proc inode it is almost certainly broken.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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To remove the hard coded proc inode numbers it is necessary to be able to
create the proc inodes during readdir. The instantiate methods are the subset
of lookup that is needed to accomplish that.
This first step just splits the lookup methods into 2 functions.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This patch generalizes the concept of files in /proc that are related to
processes but live in the root directory of /proc
Ideally this would reuse infrastructure from the rest of the process specific
parts of proc but unfortunately security_task_to_inode must not be called on
files that are not strictly per process. security_task_to_inode really needs
to be reexamined as the security label can change in important places that we
are not currently catching, but I'm not certain that simplifies this problem.
By at least matching the structure of the rest of proc we get more idiom reuse
and it becomes easier to spot problems in the way things are put together.
Later things like /proc/mounts are likely to be moved into proc_base as well.
If union mounts are ever supported we may be able to make /proc a union mount,
and properly split it into 2 filesystems.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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In some places, particularly drivers and __init code, the init utsns is the
appropriate one to use. This patch replaces those with a the init_utsname
helper.
Changes: Removed several uses of init_utsname(). Hope I picked all the
right ones in net/ipv4/ipconfig.c. These are now changed to
utsname() (the per-process namespace utsname) in the previous
patch (2/7)
[akpm@osdl.org: CIFS fix]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Cc: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Replace references to system_utsname to the per-process uts namespace
where appropriate. This includes things like uname.
Changes: Per Eric Biederman's comments, use the per-process uts namespace
for ELF_PLATFORM, sunrpc, and parts of net/ipv4/ipconfig.c
[jdike@addtoit.com: UML fix]
[clg@fr.ibm.com: cleanup]
[akpm@osdl.org: build fix]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This moves the mount namespace into the nsproxy. The mount namespace count
now refers to the number of nsproxies point to it, rather than the number of
tasks. As a result, the unshare_namespace() function in kernel/fork.c no
longer checks whether it is being shared.
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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while doing a kernel make modules_install install over an NFS mount.
=============================================
[ INFO: possible recursive locking detected ]
---------------------------------------------
nfsd/9550 is trying to acquire lock:
(&inode->i_mutex){--..}, at: [<c034c845>] mutex_lock+0x1c/0x1f
but task is already holding lock:
(&inode->i_mutex){--..}, at: [<c034c845>] mutex_lock+0x1c/0x1f
other info that might help us debug this:
2 locks held by nfsd/9550:
#0: (hash_sem){..--}, at: [<cc895223>] exp_readlock+0xd/0xf [nfsd]
#1: (&inode->i_mutex){--..}, at: [<c034c845>] mutex_lock+0x1c/0x1f
stack backtrace:
[<c0103508>] show_trace_log_lvl+0x58/0x152
[<c0103b8b>] show_trace+0xd/0x10
[<c0103c2f>] dump_stack+0x19/0x1b
[<c012aa57>] __lock_acquire+0x77a/0x9a3
[<c012af4a>] lock_acquire+0x60/0x80
[<c034c6c2>] __mutex_lock_slowpath+0xa7/0x20e
[<c034c845>] mutex_lock+0x1c/0x1f
[<c0162edc>] vfs_unlink+0x34/0x8a
[<cc891d98>] nfsd_unlink+0x18f/0x1e2 [nfsd]
[<cc89884f>] nfsd3_proc_remove+0x95/0xa2 [nfsd]
[<cc88f0d4>] nfsd_dispatch+0xc0/0x178 [nfsd]
[<c033e84d>] svc_process+0x3a5/0x5ed
[<cc88f5ba>] nfsd+0x1a7/0x305 [nfsd]
[<c0101005>] kernel_thread_helper+0x5/0xb
DWARF2 unwinder stuck at kernel_thread_helper+0x5/0xb
Leftover inexact backtrace:
[<c0103b8b>] show_trace+0xd/0x10
[<c0103c2f>] dump_stack+0x19/0x1b
[<c012aa57>] __lock_acquire+0x77a/0x9a3
[<c012af4a>] lock_acquire+0x60/0x80
[<c034c6c2>] __mutex_lock_slowpath+0xa7/0x20e
[<c034c845>] mutex_lock+0x1c/0x1f
[<c0162edc>] vfs_unlink+0x34/0x8a
[<cc891d98>] nfsd_unlink+0x18f/0x1e2 [nfsd]
[<cc89884f>] nfsd3_proc_remove+0x95/0xa2 [nfsd]
[<cc88f0d4>] nfsd_dispatch+0xc0/0x178 [nfsd]
[<c033e84d>] svc_process+0x3a5/0x5ed
[<cc88f5ba>] nfsd+0x1a7/0x305 [nfsd]
[<c0101005>] kernel_thread_helper+0x5/0xb
=============================================
[ INFO: possible recursive locking detected ]
---------------------------------------------
nfsd/9580 is trying to acquire lock:
(&inode->i_mutex){--..}, at: [<c034cc1d>] mutex_lock+0x1c/0x1f
but task is already holding lock:
(&inode->i_mutex){--..}, at: [<c034cc1d>] mutex_lock+0x1c/0x1f
other info that might help us debug this:
2 locks held by nfsd/9580:
#0: (hash_sem){..--}, at: [<cc89522b>] exp_readlock+0xd/0xf [nfsd]
#1: (&inode->i_mutex){--..}, at: [<c034cc1d>] mutex_lock+0x1c/0x1f
stack backtrace:
[<c0103508>] show_trace_log_lvl+0x58/0x152
[<c0103b8b>] show_trace+0xd/0x10
[<c0103c2f>] dump_stack+0x19/0x1b
[<c012aa63>] __lock_acquire+0x77a/0x9a3
[<c012af56>] lock_acquire+0x60/0x80
[<c034ca9a>] __mutex_lock_slowpath+0xa7/0x20e
[<c034cc1d>] mutex_lock+0x1c/0x1f
[<cc892ad1>] nfsd_setattr+0x2c8/0x499 [nfsd]
[<cc893ede>] nfsd_create_v3+0x31b/0x4ac [nfsd]
[<cc8984a1>] nfsd3_proc_create+0x128/0x138 [nfsd]
[<cc88f0d4>] nfsd_dispatch+0xc0/0x178 [nfsd]
[<c033ec1d>] svc_process+0x3a5/0x5ed
[<cc88f5ba>] nfsd+0x1a7/0x305 [nfsd]
[<c0101005>] kernel_thread_helper+0x5/0xb
DWARF2 unwinder stuck at kernel_thread_helper+0x5/0xb
Leftover inexact backtrace:
[<c0103b8b>] show_trace+0xd/0x10
[<c0103c2f>] dump_stack+0x19/0x1b
[<c012aa63>] __lock_acquire+0x77a/0x9a3
[<c012af56>] lock_acquire+0x60/0x80
[<c034ca9a>] __mutex_lock_slowpath+0xa7/0x20e
[<c034cc1d>] mutex_lock+0x1c/0x1f
[<cc892ad1>] nfsd_setattr+0x2c8/0x499 [nfsd]
[<cc893ede>] nfsd_create_v3+0x31b/0x4ac [nfsd]
[<cc8984a1>] nfsd3_proc_create+0x128/0x138 [nfsd]
[<cc88f0d4>] nfsd_dispatch+0xc0/0x178 [nfsd]
[<c033ec1d>] svc_process+0x3a5/0x5ed
[<cc88f5ba>] nfsd+0x1a7/0x305 [nfsd]
[<c0101005>] kernel_thread_helper+0x5/0xb
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Neil Brown <neilb@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Add /proc/fs/nfsd/pool_threads which allows the sysadmin (or a userspace
daemon) to read and change the number of nfsd threads in each pool. The
format is a list of space-separated integers, one per pool.
Signed-off-by: Greg Banks <gnb@melbourne.sgi.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Replace the existing list of all nfsd threads with new code using
svc_create_pooled().
Signed-off-by: Greg Banks <gnb@melbourne.sgi.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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add svc_get() for those occasions when we need to temporarily bump up
svc_serv->sv_nrthreads as a pseudo refcount.
Signed-off-by: Greg Banks <gnb@melbourne.sgi.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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If lockd_up fails - what should we expect? Do we have to later call
lockd_down?
Well the nfs client thinks "no", the nfs server thinks "yes". lockd thinks
"yes".
The only answer that really makes sense is "no" !!
So:
Make lockd_up only increment nlmsvc_users on success.
Make nfsd handle errors from lockd_up properly.
Make sure lockd_up(0) never fails when lockd is running
so that the 'reclaimer' call to lockd_up doesn't need to
be error checked.
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Thus it is printed for any path that leads to failure (make_socks is called
from two places).
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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We should be checking the return value of lockd_up when adding a new socket to
nfsd. So move the lockd_up before the svc_addsock and check the return value.
The move is because lockd_down is easy, but there is no easy way to remove a
recently added socket.
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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It isn't needed as it is available in rqstp->rq_server, and dropping it allows
some local vars to be dropped.
[akpm@osdl.org: build fix]
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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e_start acquires svc_export_cache.hash_lock, and e_stop releases it. Add
lock annotations to these two functions so that sparse can check callers
for lock pairing, and so that sparse will not complain about these
functions since they intentionally use locks in this manner.
Signed-off-by: Josh Triplett <josh@freedesktop.org>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Greg Banks <gnb@melbourne.sgi.com>
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Userspace should create and bind a socket (but not connectted) and write the
'fd' to portlist. This will cause the nfs server to listen on that socket.
To close a socket, the name of the socket - as read from 'portlist' can be
written to 'portlist' with a preceding '-'.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This file will list all ports that nfsd has open.
Default when TCP enabled will be
ipv4 udp 0.0.0.0 2049
ipv4 tcp 0.0.0.0 2049
Later, the list of ports will be settable.
'portlist' chosen rather than 'ports', to avoid unnecessary confusion with
non-mainline patches which created 'ports' with different semantics.
[akpm@osdl.org: cleanups, build fix]
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Separate out the code for creating a new service, and for creating initial
sockets.
Some of these new functions will have multiple callers soon.
[akpm@osdl.org: cleanups]
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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We have an array 'nfsd_version' which lists the available versions of nfsd,
and 'nfsd_versions' (poor choice there :-() which lists the currently active
versions.
Then we have a bitmap - nfsd_versbits which says which versions are wanted.
The bits in this bitset cause content to be copied from nfsd_version to
nfsd_versions when nfsd starts.
This patch removes nfsd_versbits and moves information directly from
nfsd_version to nfsd_versions when requests for version changes arrive.
Note that this doesn't make it possible to change versions while the server is
running. This is because serv->sv_xdrsize is calculated when a service is
created, and used when threads are created, and xdrsize depends on the active
versions.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Currently lockd listens on UDP always, and TCP if CONFIG_NFSD_TCP is set.
However as lockd performs services of the client as well, this is a problem.
If CONFIG_NfSD_TCP is not set, and a tcp mount is used, the server will not be
able to call back to lockd.
So:
- add an option to lockd_up saying which protocol is needed
- Always open sockets for which an explicit port was given, otherwise
only open a socket of the type required
- Change nfsd to do one lockd_up per socket rather than one per thread.
This
- removes the dependancy on CONFIG_NFSD_TCP
- means that lockd may open sockets other than at startup
- means that lockd will *not* listen on UDP if the only
mounts are TCP mount (and nfsd hasn't started).
The latter is the only one that concerns me at all - I don't know if this
might be a problem with some servers.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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nfsd has some cleanup that it wants to do when the last thread exits, and
there will shortly be some more. So collect this all into one place and
define a callback for an rpc service to call when the service is about to be
destroyed.
[akpm@osdl.org: cleanups, build fix]
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Greg Banks <gnb@melbourne.sgi.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Greg Banks <gnb@melbourne.sgi.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This has been needed for a long time, but now with the advent of a
reference counted struct pid there are real consequences for getting this
wrong.
Someone I think it was Oleg Nesterov pointed out that this construct was
missing locking, when I introduced struct pid. After taking time to review
the locking construct already present I figured out which lock needs to be
taken. The other paths that access f_owner.pid take either the f_owner
read or the write lock.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Define a per-container pid space object. And create one instance of this
object, init_pspace, to define the entire pid space. Subsequent patches
will provide/use interfaces to create/destroy pid spaces.
Its a subset/rework of Eric Biederman's patch
http://lkml.org/lkml/2006/2/6/285 .
Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Kirill Korotaev <dev@sw.ru>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Only touch inode's i_mtime and i_ctime to make them equal to "now" in case
they aren't yet (don't just update timestamp unconditionally). Uninline
the hash function to save 259 Bytes.
This tiny inode change which may improve cache behaviour also shaves off 8
Bytes from file_update_time() on i386.
Included a tiny codestyle cleanup, too.
Signed-off-by: Andreas Mohr <andi@lisas.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Everybody passes valid pointer there.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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File handles can be requested to send sigio and sigurg to processes. By
tracking the destination processes using struct pid instead of pid_t we make
the interface safe from all potential pid wrap around problems.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Helper functions in base.c like proc_pident_readdir and proc_pident_lookup
assume the directories have an associated task, and cannot currently be used
on the /proc root directory because it does not have such a task.
This small changes allows for base.c to be simplified and later when multiple
pid spaces are introduced it makes getting the needed context information
trivial.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Currently proc_pident_lookup gets the names and types from a table and then
has a huge switch statement to get the inode and file operations it needs.
That is silly and is becoming increasingly hard to maintain so I just put all
of the information in the table.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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There were enough changes in my last round of cleaning up proc I had to break
up the patch series into smaller chunks, and my last chunk never got resent.
This patchset gives proc dynamic inode numbers (the static inode numbers were
a pain to maintain and prevent all kinds of things), and removes the horrible
switch statements that had to be kept in sync with everything else. Being
fully table driver takes us 90% of the way of being able to register new
process specific attributes in proc.
This patch:
Group the functions by what they implement instead of by type of operation.
As it existed base.c was quickly approaching the point where it could not be
followed.
No functionality or code changes asside from adding/removing forward
declartions are implemented in this patch.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The problem: An opendir, readdir, closedir sequence can fail to report
process ids that are continually in use throughout the sequence of system
calls. For this race to trigger the process that proc_pid_readdir stops at
must exit before readdir is called again.
This can cause ps to fail to report processes, and it is in violation of
posix guarantees and normal application expectations with respect to
readdir.
Currently there is no way to work around this problem in user space short
of providing a gargantuan buffer to user space so the directory read all
happens in on system call.
This patch implements the normal directory semantics for proc, that
guarantee that a directory entry that is neither created nor destroyed
while reading the directory entry will be returned. For directory that are
either created or destroyed during the readdir you may or may not see them.
Furthermore you may seek to a directory offset you have previously seen.
These are the guarantee that ext[23] provides and that posix requires, and
more importantly that user space expects. Plus it is a simple semantic to
implement reliable service. It is just a matter of calling readdir a
second time if you are wondering if something new has show up.
These better semantics are implemented by scanning through the pids in
numerical order and by making the file offset a pid plus a fixed offset.
The pid scan happens on the pid bitmap, which when you look at it is
remarkably efficient for a brute force algorithm. Given that a typical
cache line is 64 bytes and thus covers space for 64*8 == 200 pids. There
are only 40 cache lines for the entire 32K pid space. A typical system
will have 100 pids or more so this is actually fewer cache lines we have to
look at to scan a linked list, and the worst case of having to scan the
entire pid bitmap is pretty reasonable.
If we need something more efficient we can go to a more efficient data
structure for indexing the pids, but for now what we have should be
sufficient.
In addition this takes no additional locks and is actually less code than
what we are doing now.
Also another very subtle bug in this area has been fixed. It is possible
to catch a task in the middle of de_thread where a thread is assuming the
thread of it's thread group leader. This patch carefully handles that case
so if we hit it we don't fail to return the pid, that is undergoing the
de_thread dance.
Thanks to KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> for
providing the first fix, pointing this out and working on it.
[oleg@tv-sign.ru: fix it]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Using the infrastructure created in previous patches implement support to
pipe core dumps into programs.
This is done by overloading the existing core_pattern sysctl
with a new syntax:
|program
When the first character of the pattern is a '|' the kernel will instead
threat the rest of the pattern as a command to run. The core dump will be
written to the standard input of that program instead of to a file.
This is useful for having automatic core dump analysis without filling up
disks. The program can do some simple analysis and save only a summary of
the core dump.
The core dump proces will run with the privileges and in the name space of
the process that caused the core dump.
I also increased the core pattern size to 128 bytes so that longer command
lines fit.
Most of the changes comes from allowing core dumps without seeks. They are
fairly straight forward though.
One small incompatibility is that if someone had a core pattern previously
that started with '|' they will get suddenly new behaviour. I think that's
unlikely to be a real problem though.
Additional background:
> Very nice, do you happen to have a program that can accept this kind of
> input for crash dumps? I'm guessing that the embedded people will
> really want this functionality.
I had a cheesy demo/prototype. Basically it wrote the dump to a file again,
ran gdb on it to get a backtrace and wrote the summary to a shared directory.
Then there was a simple CGI script to generate a "top 10" crashes HTML
listing.
Unfortunately this still had the disadvantage to needing full disk space for a
dump except for deleting it afterwards (in fact it was worse because over the
pipe holes didn't work so if you have a holey address map it would require
more space).
Fortunately gdb seems to be happy to handle /proc/pid/fd/xxx input pipes as
cores (at least it worked with zsh's =(cat core) syntax), so it would be
likely possible to do it without temporary space with a simple wrapper that
calls it in the right way. I ran out of time before doing that though.
The demo prototype scripts weren't very good. If there is really interest I
can dig them out (they are currently on a laptop disk on the desk with the
laptop itself being in service), but I would recommend to rewrite them for any
serious application of this and fix the disk space problem.
Also to be really useful it should probably find a way to automatically fetch
the debuginfos (I cheated and just installed them in advance). If nobody else
does it I can probably do the rewrite myself again at some point.
My hope at some point was that desktops would support it in their builtin
crash reporters, but at least the KDE people I talked too seemed to be happy
with their user space only solution.
Alan sayeth:
I don't believe that piping as such as neccessarily the right model, but
the ability to intercept and processes core dumps from user space is asked
for by many enterprise users as well. They want to know about, capture,
analyse and process core dumps, often centrally and in automated form.
[akpm@osdl.org: loff_t != unsigned long]
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Split the big and hard to read do_pipe function into smaller pieces.
This creates new create_write_pipe/free_write_pipe/create_read_pipe
functions. These functions are made global so that they can be used by
other parts of the kernel.
The resulting code is more generic and easier to read and has cleaner error
handling and less gotos.
[akpm@osdl.org: cleanup]
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Some filesystems, instead of simply decrementing i_nlink, simply zero it
during an unlink operation. We need to catch these in addition to the
decrement operations.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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OCFS2 does some operations on i_nlink, then reverts them if some of its
operations fail to complete. This does not fit in well with the
drop_nlink() logic where we expect i_nlink to stay at zero once it gets
there.
So, delay all of the nlink operations until we're sure that the operations
have completed. Also, introduce a small helper to check whether an inode
has proper "unlinkable" i_nlink counts no matter whether it is a directory
or regular inode.
This patch is broken out from the others because it does contain some
logical changes.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This is mostly included for parity with dec_nlink(), where we will have some
more hooks. This one should stay pretty darn straightforward for now.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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When a filesystem decrements i_nlink to zero, it means that a write must be
performed in order to drop the inode from the filesystem.
We're shortly going to have keep filesystems from being remounted r/o between
the time that this i_nlink decrement and that write occurs.
So, add a little helper function to do the decrements. We'll tie into it in a
bit to note when i_nlink hits zero.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The code around vfs_create() in open_namei() is getting a bit too complex.
Right now, there is at least the reference count on the dentry, and the
i_mutex to worry about. Soon, we'll also have mnt_writecount.
So, break the vfs_create() call out of open_namei(), and into a helper
function. This duplicates the call to may_open(), but that isn't such a bad
thing since the arguments (acc_mode and flag) were being heavily massaged
anyway.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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We're shortly going to be adding a bunch more permission checks in these
functions. That requires adding either a bunch of new if() conditions, or
some gotos. This patch collapses existing if()s and uses gotos instead to
prepare for the upcoming changes.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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There were a few accounting data/macros that are used in CSA but are #ifdef'ed
inside CONFIG_BSD_PROCESS_ACCT. This patch is to change those ifdef's from
CONFIG_BSD_PROCESS_ACCT to CONFIG_TASK_XACCT. A few defines are moved from
kernel/acct.c and include/linux/acct.h to kernel/tsacct.c and
include/linux/tsacct_kern.h.
Signed-off-by: Jay Lan <jlan@sgi.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Chris Sturtivant <csturtiv@sgi.com>
Cc: Tony Ernst <tee@sgi.com>
Cc: Guillaume Thouvenin <guillaume.thouvenin@bull.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This work is initially done by Zach Brown to add support for vectored aio.
These are the core changes for AIO to support
IOCB_CMD_PREADV/IOCB_CMD_PWRITEV.
[akpm@osdl.org: huge build fix]
Signed-off-by: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Acked-by: Benjamin LaHaise <bcrl@kvack.org>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This patch cleans up generic_file_*_read/write() interfaces. Christoph
Hellwig gave me the idea for this clean ups.
In a nutshell, all filesystems should set .aio_read/.aio_write methods and use
do_sync_read/ do_sync_write() as their .read/.write methods. This allows us
to cleanup all variants of generic_file_* routines.
Final available interfaces:
generic_file_aio_read() - read handler
generic_file_aio_write() - write handler
generic_file_aio_write_nolock() - no lock write handler
__generic_file_aio_write_nolock() - internal worker routine
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This patch removes readv() and writev() methods and replaces them with
aio_read()/aio_write() methods.
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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