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2008-12-23NFSv4: Clean up the asynchronous delegation returnTrond Myklebust
Reuse the state management thread in order to return delegations when we get a callback. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Clean up nfs_expire_all_delegations()Trond Myklebust
Let the actual delegreturn stuff be run in the state manager thread rather than allocating a separate kthread. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Fix a BAD_SEQUENCEID condition.Trond Myklebust
We really shouldn't be resetting the sequence ids when doing state expiration recovery, since we don't know if the server still remembers our previous state owners. There are servers out there that do attempt to preserve client state even if the lease has expired. Such a server would only release that state if a conflicting OPEN request occurs. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Don't exit the state management if there are still tasks to doTrond Myklebust
Fix up a potential race... Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Rename the state reclaimer threadTrond Myklebust
It is really a more general purpose state management thread at this point. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Clean up NFS4ERR_CB_PATH_DOWN error management...Trond Myklebust
Add a delegation cleanup phase to the state management loop, and do the NFS4ERR_CB_PATH_DOWN recovery there. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Clean up the support for returning multiple delegationsTrond Myklebust
Add a flag to mark delegations as requiring return, then run a garbage collector. In the future, this will allow for more flexible delegation management, where delegations may be marked for return if it turns out that they are not being referenced. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Add recovery for individual stateidsTrond Myklebust
NFSv4 defines a number of state errors which the client does not currently handle. Among those we should worry about are: NFS4ERR_ADMIN_REVOKED - the server's administrator revoked our locks and/or delegations. NFS4ERR_BAD_STATEID - the client and server are out of sync, possibly due to a delegation return racing with an OPEN request. NFS4ERR_OPENMODE - the client attempted to do something not sanctioned by the open mode of the stateid. Should normally just occur as a result of a delegation return race. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Remove nfs_client->cl_semTrond Myklebust
Now that we're using the flags to indicate state that needs to be recovered, as well as having implemented proper refcounting and spinlocking on the state and open_owners, we can get rid of nfs_client->cl_sem. The only remaining case that was dubious was the file locking, and that case is now covered by the nfsi->rwsem. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Ensure that file unlock requests don't conflict with state recoveryTrond Myklebust
The unlock path is currently failing to take the nfs_client->cl_sem read lock, and hence the recovery path may see locks disappear from underneath it. Also ensure that it takes the nfs_inode->rwsem read lock so that it there is no conflict with delegation recalls. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFS: Remove the unnecessary argument to nfs4_wait_clnt_recover()Trond Myklebust
...and move some code around in order to clear out an unnecessary forward declaration. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Ensure that nfs4_reclaim_open_state() doesn't depend on cl_semTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Add a recovery marking scheme for state ownersTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Don't tell server we rebooted when not necessaryTrond Myklebust
Instead of doing a full setclientid, try doing a RENEW call first. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Remove redundant RENEW calls if we know the lease has expiredTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Fix state recovery when the client runs over the grace periodTrond Myklebust
If the client for some reason is not able to recover all its state within the time allotted for the grace period, and the server reboots again, the client is not allowed to recover the state that was 'lost' using reboot recovery. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Callers to nfs4_get_renew_cred() need to hold nfs_client->cl_lockTrond Myklebust
Ditto for nfs4_get_setclientid_cred(). Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Clean up for the state loss reclaimerTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFS: Use atomic bitops when changing struct nfs_delegation->flagsTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Fix up the dereferencing of delegation->inodeTrond Myklebust
Without an extra lock, we cannot just assume that the delegation->inode is valid when we're traversing the rcu-protected nfs_client lists. Use the delegation->lock to ensure that it is truly valid. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFSv4: Fix up another delegation related raceTrond Myklebust
When we can update_open_stateid(), we need to be certain that we don't race with a delegation return. While we could do this by grabbing the nfs_client->cl_lock, a dedicated spin lock in the delegation structure will scale better. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NLM: allow lockd requests from an unprivileged portChuck Lever
If the admin has specified the "noresvport" option for an NFS mount point, the kernel's NFS client uses an unprivileged source port for the main NFS transport. The kernel's lockd client should use an unprivileged port in this case as well. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFS: "[no]resvport" mount option changes mountd client tooChuck Lever
If the admin has specified the "noresvport" option for an NFS mount point, the kernel's NFS client uses an unprivileged source port for the main NFS transport. The kernel's mountd client should use an unprivileged port in this case as well. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFS: add "[no]resvport" mount optionChuck Lever
The standard default security setting for NFS is AUTH_SYS. An NFS client connects to NFS servers via a privileged source port and a fixed standard destination port (2049). The client sends raw uid and gid numbers to identify users making NFS requests, and the server assumes an appropriate authority on the client has vetted these values because the source port is privileged. On Linux, by default in-kernel RPC services use a privileged port in the range between 650 and 1023 to avoid using source ports of well- known IP services. Using such a small range limits the number of NFS mount points and the number of unique NFS servers to which a client can connect concurrently. An NFS client can use unprivileged source ports to expand the range of source port numbers, allowing more concurrent server connections and more NFS mount points. Servers must explicitly allow NFS connections from unprivileged ports for this to work. In the past, bumping the value of the sunrpc.max_resvport sysctl on the client would permit the NFS client to use unprivileged ports. Bumping this setting also changes the maximum port number used by other in-kernel RPC services, some of which still required a port number less than 1023. This is exacerbated by the way source port numbers are chosen by the Linux RPC client, which starts at the top of the range and works downwards. It means that bumping the maximum means all RPC services requesting a source port will likely get an unprivileged port instead of a privileged one. Changing this setting effects all NFS mount points on a client. A sysadmin could not selectively choose which mount points would use non-privileged ports and which could not. Lastly, this mechanism of expanding the limit on the number of NFS mount points was entirely undocumented. To address the need for the NFS client to use a large range of source ports without interfering with the activity of other in-kernel RPC services, we introduce a new NFS mount option. This option explicitly tells only the NFS client to use a non-privileged source port when communicating with the NFS server for one specific mount point. This new mount option is called "resvport," like the similar NFS mount option on FreeBSD and Mac OS X. A sister patch for nfs-utils will be submitted that documents this new option in nfs(5). The default setting for this new mount option requires the NFS client to use a privileged port, as before. Explicitly specifying the "noresvport" mount option allows the NFS client to use an unprivileged source port for this mount point when connecting to the NFS server port. This mount option is supported only for text-based NFS mounts. [ Sidebar: it is widely known that security mechanisms based on the use of privileged source ports are ineffective. However, the NFS client can combine the use of unprivileged ports with the use of secure authentication mechanisms, such as Kerberos. This allows a large number of connections and mount points while ensuring a useful level of security. Eventually we may change the default setting for this option depending on the security flavor used for the mount. For example, if the mount is using only AUTH_SYS, then the default setting will be "resvport;" if the mount is using a strong security flavor such as krb5, the default setting will be "noresvport." ] Signed-off-by: Chuck Lever <chuck.lever@oracle.com> [Trond.Myklebust@netapp.com: Fixed a bug whereby nfs4_init_client() was being called with incorrect arguments.] Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFS: move nfs_server flag initializationChuck Lever
Make it possible for the NFSv4 mount set up logic to pass mount option flags down the stack to nfs_create_rpc_client(). This is immediately useful if we want NFS mount options to modulate settings of the underlying RPC transport, but it may be useful at some later point if other parts of the NFSv4 mount initialization logic want to know what the mount options are. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFS: expand flags passed to nfs_create_rpc_client()Chuck Lever
The nfs_create_rpc_client() function sets up an RPC client for an NFS mount point. Add an option that allows it to set up an RPC transport from an unprivileged port. Instead of having nfs_create_rpc_client()'s callers retain local knowledge about how to set up an RPC client, create a couple of flag arguments to control the use of RPC_CLNT_CREATE flags. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFS: introduce nfs_mount_info struct for calling nfs_mount()Chuck Lever
Clean up: convert nfs_mount() to take a single data structure argument to make it simpler to add more arguments. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFS: Move declaration of nfs_mount() to fs/nfs/internal.hChuck Lever
Clean up: The nfs_mount() function is not to be used outside of the NFS client. Move its public declaration to fs/nfs/internal.h. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23NFS: rename nfs_path variableChuck Lever
Clean up: I'm about to move the declaration of nfs_mount into fs/nfs/internal.h and include it in fs/nfs/nfsroot.c. There's a conflicting definition of nfs_path in fs/nfs/internal.h and fs/nfs/nfsroot.c, so rename the private one. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23lockd: convert reclaimer thread to kthread interfaceJeff Layton
My understanding is that there is a push to turn the kernel_thread interface into a non-exported symbol and move all kernel threads to use the kthread API. This patch changes lockd to use kthread_run to spawn the reclaimer thread. I've made the assumption here that the extra module references taken when we spawn this thread are unnecessary and removed them. I've also added a KERN_ERR printk that pops if the thread can't be spawned to warn the admin that the locks won't be reclaimed. In the future, it would be nice to be able to notify userspace that locks have been lost (probably by implementing SIGLOST), and adding some good policies about how long we should reattempt to reclaim the locks. Finally, I removed a comment about memory leaks that I believe is obsolete and added a new one to clarify the result of sending a SIGKILL to the reclaimer thread. As best I can tell, doing so doesn't actually cause a memory leak. I consider this patch 2.6.29 material. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23LOCKD: Make lockd_up() and lockd_down() exported GPL-onlyTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23SUNRPC: nfsacl_encode/nfsacl_decode should be exported as GPL-onlyTrond Myklebust
Again, this has never been intended as a public abi for out-of-tree modules. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-23nfs: remove redundant tests on reading new pagesWu Fengguang
aops->readpages() and its NFS helper readpage_async_filler() will only be called to do readahead I/O for newly allocated pages. So it's not necessary to test for the always 0 dirty/uptodate page flags. The removal of nfs_wb_page() call also fixes a readahead bug: the NFS readahead has been synchronous since 2.6.23, because that call will clear PG_readahead, which is the reminder for asynchronous readahead. More background: the PG_readahead page flag is shared with PG_reclaim, one for read path and the other for write path. clear_page_dirty_for_io() unconditionally clears PG_readahead to prevent possible readahead residuals, assuming itself to be always called in the write path. However, NFS is one and the only exception in that it _always_ calls clear_page_dirty_for_io() in the read path, i.e. for readpages()/readpage(). Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Wu Fengguang <wfg@linux.intel.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-12-19fs/9p: change simple_strtol to simple_strtoulJulia Lawall
Since v9ses->uid is unsigned, it would seem better to use simple_strtoul that simple_strtol. A simplified version of the semantic patch that makes this change is as follows: (http://www.emn.fr/x-info/coccinelle/) // <smpl> @r2@ long e; position p; @@ e = simple_strtol@p(...) @@ position p != r2.p; type T; T e; @@ e = - simple_strtol@p + simple_strtoul (...) // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Acked-by: Eric Van Hensbergen <ericvh@gmail.com>
2008-12-199p: convert d_iname references to d_name.nameWu Fengguang
d_iname is rubbish for long file names. Use d_name.name in printks instead. Signed-off-by: Wu Fengguang <wfg@linux.intel.com> Acked-by: Eric Van Hensbergen <ericvh@gmail.com>
2008-12-199p: Remove potentially bad parameter from function entry debug print.Duane Griffin
Signed-off-by: Duane Griffin <duaneg@dghda.com> Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2008-12-17Merge branch 'upstream-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mfasheh/ocfs2 * 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mfasheh/ocfs2: ocfs2: Add JBD2 compat feature bit. ocfs2: Always update xattr search when creating bucket.
2008-12-17cifs: fix buffer overrun in parse_DFS_referralsJeff Layton
While testing a kernel with memory poisoning enabled, I saw some warnings about the redzone getting clobbered when chasing DFS referrals. The buffer allocation for the unicode converted version of the searchName is too small and needs to take null termination into account. Signed-off-by: Jeff Layton <jlayton@redhat.com> Acked-by: Steve French <sfrench@us.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-16ocfs2: Add JBD2 compat feature bit.Joel Becker
Define the OCFS2_FEATURE_COMPAT_JBD2 bit in the filesystem header. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-12-16ocfs2: Always update xattr search when creating bucket.Tao Ma
When we create xattr bucket during the process of xattr set, we always need to update the ocfs2_xattr_search since even if the bucket size is the same as block size, the offset will change because of the removal of the ocfs2_xattr_block header. Signed-off-by: Tao Ma <tao.ma@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-12-10Merge branch 'to-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/frob/linux-2.6-roland * 'to-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/frob/linux-2.6-roland: tracehook: exec double-reporting fix
2008-12-10KSYM_SYMBOL_LEN fixesHugh Dickins
Miles Lane tailing /sys files hit a BUG which Pekka Enberg has tracked to my 966c8c12dc9e77f931e2281ba25d2f0244b06949 sprint_symbol(): use less stack exposing a bug in slub's list_locations() - kallsyms_lookup() writes a 0 to namebuf[KSYM_NAME_LEN-1], but that was beyond the end of page provided. The 100 slop which list_locations() allows at end of page looks roughly enough for all the other stuff it might print after the symbol before it checks again: break out KSYM_SYMBOL_LEN earlier than before. Latencytop and ftrace and are using KSYM_NAME_LEN buffers where they need KSYM_SYMBOL_LEN buffers, and vmallocinfo a 2*KSYM_NAME_LEN buffer where it wants a KSYM_SYMBOL_LEN buffer: fix those before anyone copies them. [akpm@linux-foundation.org: ftrace.h needs module.h] Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc Miles Lane <miles.lane@gmail.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Acked-by: Steven Rostedt <srostedt@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-10inotify: fix IN_ONESHOT unmount event watcherDmitri Monakhov
On umount two event will be dispatched to watcher: 1: inotify_dev_queue_event(.., IN_UNMOUNT,..) 2: remove_watch(watch, dev) ->inotify_dev_queue_event(.., IN_IGNORED, ..) But if watcher has IN_ONESHOT bit set then the watcher will be released inside first event. Which result in accessing invalid object later. IMHO it is not pure regression. This bug wasn't triggered while initial inotify interface testing phase because of another bug in IN_ONESHOT handling logic :) commit ac74c00e499ed276a965e5b5600667d5dc04a84a Author: Ulisses Furquim <ulissesf@gmail.com> Date: Fri Feb 8 04:18:16 2008 -0800 inotify: fix check for one-shot watches before destroying them As the IN_ONESHOT bit is never set when an event is sent we must check it in the watch's mask and not in the event's mask. TESTCASE: mkdir mnt mount -ttmpfs none mnt mkdir mnt/d ./inotify mnt/d& umount mnt ## << lockup or crash here TESTSOURCE: /* gcc -oinotify inotify.c */ #include <stdio.h> #include <stdlib.h> #include <sys/inotify.h> int main(int argc, char **argv) { char buf[1024]; struct inotify_event *ie; char *p; int i; ssize_t l; p = argv[1]; i = inotify_init(); inotify_add_watch(i, p, ~0); l = read(i, buf, sizeof(buf)); printf("read %d bytes\n", l); ie = (struct inotify_event *) buf; printf("event mask: %d\n", ie->mask); return 0; } Signed-off-by: Dmitri Monakhov <dmonakhov@openvz.org> Cc: John McCutchan <ttb@tentacle.dhs.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Robert Love <rlove@google.com> Cc: Ulisses Furquim <ulissesf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-10pagemap: fix 32-bit pagemap regressionMatt Mackall
The large pages fix from bcf8039ed45 broke 32-bit pagemap by pulling the pagemap entry code out into a function with the wrong return type. Pagemap entries are 64 bits on all systems and unsigned long is only 32 bits on 32-bit systems. Signed-off-by: Matt Mackall <mpm@selenic.com> Reported-by: Doug Graham <dgraham@nortel.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: <stable@kernel.org> [2.6.26.x, 2.6.27.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-10revert "percpu_counter: new function percpu_counter_sum_and_set"Andrew Morton
Revert commit e8ced39d5e8911c662d4d69a342b9d053eaaac4e Author: Mingming Cao <cmm@us.ibm.com> Date: Fri Jul 11 19:27:31 2008 -0400 percpu_counter: new function percpu_counter_sum_and_set As described in revert "percpu counter: clean up percpu_counter_sum_and_set()" the new percpu_counter_sum_and_set() is racy against updates to the cpu-local accumulators on other CPUs. Revert that change. This means that ext4 will be slow again. But correct. Reported-by: Eric Dumazet <dada1@cosmosbay.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mingming Cao <cmm@us.ibm.com> Cc: <linux-ext4@vger.kernel.org> Cc: <stable@kernel.org> [2.6.27.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-10revert "percpu counter: clean up percpu_counter_sum_and_set()"Andrew Morton
Revert commit 1f7c14c62ce63805f9574664a6c6de3633d4a354 Author: Mingming Cao <cmm@us.ibm.com> Date: Thu Oct 9 12:50:59 2008 -0400 percpu counter: clean up percpu_counter_sum_and_set() Before this patch we had the following: percpu_counter_sum(): return the percpu_counter's value percpu_counter_sum_and_set(): return the percpu_counter's value, copying that value into the central value and zeroing the per-cpu counters before returning. After this patch, percpu_counter_sum_and_set() has gone, and percpu_counter_sum() gets the old percpu_counter_sum_and_set() functionality. Problem is, as Eric points out, the old percpu_counter_sum_and_set() functionality was racy and wrong. It zeroes out counters on "other" cpus, without holding any locks which will prevent races agaist updates from those other CPUS. This patch reverts 1f7c14c62ce63805f9574664a6c6de3633d4a354. This means that percpu_counter_sum_and_set() still has the race, but percpu_counter_sum() does not. Note that this is not a simple revert - ext4 has since started using percpu_counter_sum() for its dirty_blocks counter as well. Note that this revert patch changes percpu_counter_sum() semantics. Before the patch, a call to percpu_counter_sum() will bring the counter's central counter mostly up-to-date, so a following percpu_counter_read() will return a close value. After this patch, a call to percpu_counter_sum() will leave the counter's central accumulator unaltered, so a subsequent call to percpu_counter_read() can now return a significantly inaccurate result. If there is any code in the tree which was introduced after e8ced39d5e8911c662d4d69a342b9d053eaaac4e was merged, and which depends upon the new percpu_counter_sum() semantics, that code will break. Reported-by: Eric Dumazet <dada1@cosmosbay.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mingming Cao <cmm@us.ibm.com> Cc: <linux-ext4@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-09tracehook: exec double-reporting fixRoland McGrath
The patch 6341c39 "tracehook: exec" introduced a small regression in 2.6.27 regarding binfmt_misc exec event reporting. Since the reporting is now done in the common search_binary_handler() function, an exec of a misc binary will result in two (or possibly multiple) exec events being reported, instead of just a single one, because the misc handler contains a recursive call to search_binary_handler. To add to the confusion, if PTRACE_O_TRACEEXEC is not active, the multiple SIGTRAP signals will in fact cause only a single ptrace intercept, as the signals are not queued. However, if PTRACE_O_TRACEEXEC is on, the debugger will actually see multiple ptrace intercepts (PTRACE_EVENT_EXEC). The test program included below demonstrates the problem. This change fixes the bug by calling tracehook_report_exec() only in the outermost search_binary_handler() call (bprm->recursion_depth == 0). The additional change to restore bprm->recursion_depth after each binfmt load_binary call is actually superfluous for this bug, since we test the value saved on entry to search_binary_handler(). But it keeps the use of of the depth count to its most obvious expected meaning. Depending on what binfmt handlers do in certain cases, there could have been false-positive tests for recursion limits before this change. /* Test program using PTRACE_O_TRACEEXEC. This forks and exec's the first argument with the rest of the arguments, while ptrace'ing. It expects to see one PTRACE_EVENT_EXEC stop and then a successful exit, with no other signals or events in between. Test for kernel doing two PTRACE_EVENT_EXEC stops for a binfmt_misc exec: $ gcc -g traceexec.c -o traceexec $ sudo sh -c 'echo :test:M::foobar::/bin/cat: > /proc/sys/fs/binfmt_misc/register' $ echo 'foobar test' > ./foobar $ chmod +x ./foobar $ ./traceexec ./foobar; echo $? ==> good <== foobar test 0 $ ==> bad <== foobar test unexpected status 0x4057f != 0 3 $ */ #include <stdio.h> #include <sys/types.h> #include <sys/wait.h> #include <sys/ptrace.h> #include <unistd.h> #include <signal.h> #include <stdlib.h> static void wait_for (pid_t child, int expect) { int status; pid_t p = wait (&status); if (p != child) { perror ("wait"); exit (2); } if (status != expect) { fprintf (stderr, "unexpected status %#x != %#x\n", status, expect); exit (3); } } int main (int argc, char **argv) { pid_t child = fork (); if (child < 0) { perror ("fork"); return 127; } else if (child == 0) { ptrace (PTRACE_TRACEME); raise (SIGUSR1); execv (argv[1], &argv[1]); perror ("execve"); _exit (127); } wait_for (child, W_STOPCODE (SIGUSR1)); if (ptrace (PTRACE_SETOPTIONS, child, 0L, (void *) (long) PTRACE_O_TRACEEXEC) != 0) { perror ("PTRACE_SETOPTIONS"); return 4; } if (ptrace (PTRACE_CONT, child, 0L, 0L) != 0) { perror ("PTRACE_CONT"); return 5; } wait_for (child, W_STOPCODE (SIGTRAP | (PTRACE_EVENT_EXEC << 8))); if (ptrace (PTRACE_CONT, child, 0L, 0L) != 0) { perror ("PTRACE_CONT"); return 6; } wait_for (child, W_EXITCODE (0, 0)); return 0; } Reported-by: Arnd Bergmann <arnd@arndb.de> CC: Ulrich Weigand <ulrich.weigand@de.ibm.com> Signed-off-by: Roland McGrath <roland@redhat.com>
2008-12-08EXPORTFS: handle NULL returns from fh_to_dentry()/fh_to_parent()J. Bruce Fields
While 440037287c5 "[PATCH] switch all filesystems over to d_obtain_alias" removed some cases where fh_to_dentry() and fh_to_parent() could return NULL, there are still a few NULL returns left in individual filesystems. Thus it was a mistake for that commit to remove the handling of NULL returns in the callers. Revert those parts of 440037287c5 which removed the NULL handling. (We could, alternatively, modify all implementations to return -ESTALE instead of NULL, but that proves to require fixing a number of filesystems, and in some cases it's arguably more natural to return NULL.) Thanks to David for original patch and Linus, Christoph, and Hugh for review. Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Cc: David Howells <dhowells@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-05Fix a race condition in FASYNC handlingJonathan Corbet
Changeset a238b790d5f99c7832f9b73ac8847025815b85f7 (Call fasync() functions without the BKL) introduced a race which could leave file->f_flags in a state inconsistent with what the underlying driver/filesystem believes. Revert that change, and also fix the same races in ioctl_fioasync() and ioctl_fionbio(). This is a minimal, short-term fix; the real fix will not involve the BKL. Reported-by: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: stable@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-04Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/bdev * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/bdev: [PATCH] fix bogus argument of blkdev_put() in pktcdvd [PATCH 2/2] documnt FMODE_ constants [PATCH 1/2] kill FMODE_NDELAY_NOW [PATCH] clean up blkdev_get a little bit [PATCH] Fix block dev compat ioctl handling [PATCH] kill obsolete temporary comment in swsusp_close()