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2006-06-23[PATCH] fs/locks.c: make posix_locks_deadlock() staticAdrian Bunk1-3/+1
We can now make posix_locks_deadlock() static. Signed-off-by: Adrian Bunk <bunk@stusta.de> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23[PATCH] vfs: add lock owner argument to flush operationMiklos Szeredi1-1/+1
Pass the POSIX lock owner ID to the flush operation. This is useful for filesystems which don't want to store any locking state in inode->i_flock but want to handle locking/unlocking POSIX locks internally. FUSE is one such filesystem but I think it possible that some network filesystems would need this also. Also add a flag to indicate that a POSIX locking request was generated by close(), so filesystems using the above feature won't send an extra locking request in this case. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23[PATCH] locks: clean up locks_remove_posix()Miklos Szeredi1-20/+5
locks_remove_posix() can use posix_lock_file() instead of doing the lock removal by hand. posix_lock_file() now does exacly the same. The comment about pids no longer applies, posix_lock_file() takes only the owner into account. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23[PATCH] locks: don't do unnecessary allocationsMiklos Szeredi1-3/+10
posix_lock_file() always allocates new locks in advance, even if it's easy to determine that no allocations will be needed. Optimize these cases: - FL_ACCESS flag is set - Unlocking the whole range Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23[PATCH] locks: don't unnecessarily fail posix lock operationsMiklos Szeredi1-7/+15
posix_lock_file() was too cautious, failing operations on OOM, even if they didn't actually require an allocation. This has the disadvantage, that a failing unlock on process exit could lead to a memory leak. There are two possibilites for this: - filesystem implements .lock() and calls back to posix_lock_file(). On cleanup of files_struct locks_remove_posix() is called which should remove all locks belonging to files_struct. However if filesystem calls posix_lock_file() which fails, then those locks will never be freed. - if a file is closed while a lock is blocked, then after acquiring fcntl_setlk() will undo the lock. But this unlock itself might fail on OOM, again possibly leaking the lock. The solution is to move the checking of the allocations until after it is sure that they will be needed. This will solve the above problem since unlock will always succeed unless it splits an existing region. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-22[PATCH] remove steal_locks()Miklos Szeredi1-57/+0
This patch removes the steal_locks() function. steal_locks() doesn't work correctly with any filesystem that does it's own lock management, including NFS, CIFS, etc. In addition it has weird semantics on local filesystems in case tasks sharing file-descriptor tables are doing POSIX locking operations in parallel to execve(). The steal_locks() function has an effect on applications doing: clone(CLONE_FILES) /* in child */ lock execve lock POSIX locks acquired before execve (by "child", "parent" or any further task sharing files_struct) will after the execve be owned exclusively by "child". According to Chris Wright some LSB/LTP kind of suite triggers without the stealing behavior, but there's no known real-world application that would also fail. Apps using NPTL are not affected, since all other threads are killed before execve. Apps using LinuxThreads are only affected if they - have multiple threads during exec (LinuxThreads doesn't kill other threads, the app may do it with pthread_kill_other_threads_np()) - rely on POSIX locks being inherited across exec Both conditions are documented, but not their interaction. Apps using clone() natively are affected if they - use clone(CLONE_FILES) - rely on POSIX locks being inherited across exec The above scenarios are unlikely, but possible. If the patch is vetoed, there's a plan B, that involves mostly keeping the weird stealing semantics, but changing the way lock ownership is handled so that network and local filesystems work consistently. That would add more complexity though, so this solution seems to be preferred by most people. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Matthew Wilcox <willy@debian.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Steven French <sfrench@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-14[PATCH] Return error in case flock_lock_file failureKirill Korotaev1-0/+2
If flock_lock_file() failed to allocate flock with locks_alloc_lock() then "error = 0" is returned. Need to return some non-zero. Signed-off-by: Pavel Emelianov <xemul@openvz.org> Signed-off-by: Kirill Korotaev <dev@openvz.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-05-08[PATCH] fs/locks.c: Fix lease_initTrond Myklebust1-9/+12
It is insane to be giving lease_init() the task of freeing the lock it is supposed to initialise, given that the lock is not guaranteed to be allocated on the stack. This causes lockups in fcntl_setlease(). Problem diagnosed by Daniel Hokka Zakrisson <daniel@hozac.com> Also fix a slab leak in __setlease() due to an uninitialised return value. Problem diagnosed by Björn Steinbrink. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Tested-by: Daniel Hokka Zakrisson <daniel@hozac.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-19[PATCH] Fix file lookup without refDipankar Sarma1-2/+7
There are places in the kernel where we look up files in fd tables and access the file structure without holding refereces to the file. So, we need special care to avoid the race between looking up files in the fd table and tearing down of the file in another CPU. Otherwise, one might see a NULL f_dentry or such torn down version of the file. This patch fixes those special places where such a race may happen. Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com> Acked-by: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-31[PATCH] fs/locks.c: Fix sys_flock() raceTrond Myklebust1-14/+16
sys_flock() currently has a race which can result in a double free in the multi-thread case. Thread 1 Thread 2 sys_flock(file, LOCK_EX) sys_flock(file, LOCK_UN) If Thread 2 removes the lock from inode->i_lock before Thread 1 tests for list_empty(&lock->fl_link) at the end of sys_flock, then both threads will end up calling locks_free_lock for the same lock. Fix is to make flock_lock_file() do the same as posix_lock_file(), namely to make a copy of the request, so that the caller can always free the lock. This also has the side-effect of fixing up a reference problem in the lockd handling of flock. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-31[PATCH] locks: don't panicMiklos Szeredi1-12/+3
Don't panic! Just BUG_ON(). Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-26[PATCH] VFS,fs/locks.c,NFSD4: add race_free posix_lock_file_conf() interfaceAndy Adamson1-8/+24
Lockd and the NFSv4 server both exercise a race condition where posix_test_lock() is called either before or after posix_lock_file() to deal with a denied lock request due to a conflicting lock. Remove the race condition for the NFSv4 server by adding a new conflicting lock parameter to __posix_lock_file() , changing the name to __posix_lock_file_conf(). Keep posix_lock_file() interface, add posix_lock_conf() interface, both call __posix_lock_file_conf(). [akpm@osdl.org: Put the EXPORT_SYMBOL() where it belongs] Signed-off-by: Andy Adamson <andros@citi.umich.edu> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-26[PATCH] VFS,fs/locks.c: cleanup locks_insert_blockJ. Bruce Fields1-6/+1
BUG instead of handling a case that should never happen. Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-26[PATCH] Use __read_mostly on some hot fs variablesEric Dumazet1-1/+1
I discovered on oprofile hunting on a SMP platform that dentry lookups were slowed down because d_hash_mask, d_hash_shift and dentry_hashtable were in a cache line that contained inodes_stat. So each time inodes_stats is changed by a cpu, other cpus have to refill their cache line. This patch moves some variables to the __read_mostly section, in order to avoid false sharing. RCU dentry lookups can go full speed. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-20lockd: stop abusing file_lock_listChristoph Hellwig1-4/+1
Currently lockd directly access the file_lock_list from fs/locks.c. It does so to mark locks granted or reclaimable. This is very suboptimal, because a) lockd needs to poke into locks.c internals, and b) it needs to iterate over all locks in the system for marking locks granted or reclaimable. This patch adds lists for granted and reclaimable locks to the nlm_host structure instead, and adds locks to those. nlmclnt_lock: now adds the lock to h_granted instead of setting the NFS_LCK_GRANTED, still O(1) nlmclnt_mark_reclaim: goes away completely, replaced by a list_splice_init. Complexity reduced from O(locks in the system) to O(1) reclaimer: iterates over h_reclaim now, complexity reduced from O(locks in the system) to O(locks per nlm_host) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-03-20lockd: posix_test_lock() should not call locks_copy_lock()Trond Myklebust1-5/+13
The caller of posix_test_lock() should never need to look at the lock private data, so do not copy that information. This also means that there is no need to call the fl_release_private methods. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-03-20locks,lockd: fix race in nlmsvc_testlockAndy Adamson1-8/+13
posix_test_lock() returns a pointer to a struct file_lock which is unprotected and can be removed while in use by the caller. Move the conflicting lock from the return to a parameter, and copy the conflicting lock. In most cases the caller ends up putting the copy of the conflicting lock on the stack. On i386, sizeof(struct file_lock) appears to be about 100 bytes. We're assuming that's reasonable. Signed-off-by: Andy Adamson <andros@citi.umich.edu> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-03-20locks: remove unused posix_block_lockAndy Adamson1-15/+0
posix_lock_file() is used to add a blocked lock to Lockd's block, so posix_block_lock() is no longer needed. Signed-off-by: Andy Adamson <andros@citi.umich.edu> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-03-20VFS: Fix __posix_lock_file() copy of private lock areaTrond Myklebust1-17/+36
The struct file_lock->fl_u area must be copied using the fl_copy_lock() operation. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-08[PATCH] tiny: Uninline some fslocks.c functionsMatt Mackall1-4/+3
uninline some file locking functions add/remove: 3/0 grow/shrink: 0/15 up/down: 256/-1525 (-1269) function old new delta locks_free_lock - 134 +134 posix_same_owner - 69 +69 __locks_delete_block - 53 +53 posix_locks_conflict 126 108 -18 locks_remove_posix 266 237 -29 locks_wake_up_blocks 121 87 -34 locks_block_on_timeout 83 47 -36 locks_insert_block 157 120 -37 locks_delete_block 62 23 -39 posix_unblock_lock 104 59 -45 posix_locks_deadlock 162 100 -62 locks_delete_lock 228 119 -109 sys_flock 338 217 -121 __break_lease 600 474 -126 lease_init 252 122 -130 fcntl_setlk64 793 649 -144 fcntl_setlk 793 649 -144 __posix_lock_file 1477 1026 -451 Signed-off-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06NLM: Further cancel fixesJ. Bruce Fields1-1/+6
If the server receives an NLM cancel call and finds no waiting lock to cancel, then chances are the lock has already been applied, and the client just hadn't yet processed the NLM granted callback before it sent the cancel. The Open Group text, for example, perimts a server to return either success (LCK_GRANTED) or failure (LCK_DENIED) in this case. But returning an error seems more helpful; the client may be able to use it to recognize that a race has occurred and to recover from the race. So, modify the relevant functions to return an error in this case. Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06NLM: don't unlock on cancel requestsJ. Bruce Fields1-11/+2
Currently when lockd gets an NLM_CANCEL request, it also does an unlock for the same range. This is incorrect. The Open Group documentation says that "This procedure cancels an *outstanding* blocked lock request." (Emphasis mine.) Also, consider a client that holds a lock on the first byte of a file, and requests a lock on the entire file. If the client cancels that request (perhaps because the requesting process is signalled), the server shouldn't apply perform an unlock on the entire file, since that will also remove the previous lock that the client was already granted. Or consider a lock request that actually *downgraded* an exclusive lock to a shared lock. Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-11-13[PATCH] VFS: local denial-of-service with file leasesChris Wright1-1/+0
Remove time_out_leases() printk that's easily triggered by users. Signed-off-by: Chris Wright <chrisw@osdl.org> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-11-13[PATCH] VFS: Fix memory leak with file leasesJ. Bruce Fields1-1/+1
The patch http://linux.bkbits.net:8080/linux-2.6/diffs/fs/locks.c@1.70??nav=index.html introduced a pretty nasty memory leak in the lease code. When freeing the lease, the code in locks_delete_lock() will correctly clean up the fasync queue, but when we return to fcntl_setlease(), the freed fasync entry will be reinstated. This patch ensures that we skip the call to fasync_helper() when we're freeing up the lease. Signed-off-by: J. Bruce Fields <bfields@fieldses.org> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-10-18Fix Connectathon locking test failureTrond Myklebust1-17/+25
We currently fail Connectathon test 6.10 in the case of 32-bit locks due to incorrect error checking. Also add support for l->l_len < 0 to 64-bit locks. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-09-23From: Olaf Kirch <okir@suse.de>Olaf Kirch1-1/+5
[PATCH] Fix miscompare in __posix_lock_file If an application requests the same lock twice, the kernel should just leave the existing lock in place. Currently, it will install a second lock of the same type. Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-09-17[PATCH] files: fix preemption issuesDipankar Sarma1-0/+3
With the new fdtable locking rules, you have to protect fdtable with either ->file_lock or rcu_read_lock/unlock(). There are some places where we aren't doing either. This patch fixes those places. Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] files: break up files structDipankar Sarma1-3/+5
In order for the RCU to work, the file table array, sets and their sizes must be updated atomically. Instead of ensuring this through too many memory barriers, we put the arrays and their sizes in a separate structure. This patch takes the first step of putting the file table elements in a separate structure fdtable that is embedded withing files_struct. It also changes all the users to refer to the file table using files_fdtable() macro. Subsequent applciation of RCU becomes easier after this. Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com> Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-27[PATCH] stale POSIX lock handlingPeter Staubach1-33/+48
I believe that there is a problem with the handling of POSIX locks, which the attached patch should address. The problem appears to be a race between fcntl(2) and close(2). A multithreaded application could close a file descriptor at the same time as it is trying to acquire a lock using the same file descriptor. I would suggest that that multithreaded application is not providing the proper synchronization for itself, but the OS should still behave correctly. SUS3 (Single UNIX Specification Version 3, read: POSIX) indicates that when a file descriptor is closed, that all POSIX locks on the file, owned by the process which closed the file descriptor, should be released. The trick here is when those locks are released. The current code releases all locks which exist when close is processing, but any locks in progress are handled when the last reference to the open file is released. There are three cases to consider. One is the simple case, a multithreaded (mt) process has a file open and races to close it and acquire a lock on it. In this case, the close will release one reference to the open file and when the fcntl is done, it will release the other reference. For this situation, no locks should exist on the file when both the close and fcntl operations are done. The current system will handle this case because the last reference to the open file is being released. The second case is when the mt process has dup(2)'d the file descriptor. The close will release one reference to the file and the fcntl, when done, will release another, but there will still be at least one more reference to the open file. One could argue that the existence of a lock on the file after the close has completed is okay, because it was acquired after the close operation and there is still a way for the application to release the lock on the file, using an existing file descriptor. The third case is when the mt process has forked, after opening the file and either before or after becoming an mt process. In this case, each process would hold a reference to the open file. For each process, this degenerates to first case above. However, the lock continues to exist until both processes have released their references to the open file. This lock could block other lock requests. The changes to release the lock when the last reference to the open file aren't quite right because they would allow the lock to exist as long as there was a reference to the open file. This is too long. The new proposed solution is to add support in the fcntl code path to detect a race with close and then to release the lock which was just acquired when such as race is detected. This causes locks to be released in a timely fashion and for the system to conform to the POSIX semantic specification. This was tested by instrumenting a kernel to detect the handling locks and then running a program which generates case #3 above. A dangling lock could be reliably generated. When the changes to detect the close/fcntl race were added, a dangling lock could no longer be generated. Cc: Matthew Wilcox <willy@debian.org> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-07[PATCH] coverity: fs/locks.c flp null checkKAMBAROV, ZAUR1-1/+3
We're dereferencing `flp' and then we're testing it for NULLness. Either the compiler accidentally saved us or the existing null-pointer checdk is redundant. This defect was found automatically by Coverity Prevent, a static analysis tool. Signed-off-by: Zaur Kambarov <zkambarov@coverity.com> Cc: Matthew Wilcox <willy@debian.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-22[PATCH] VFS: Ensure that all the on-stack struct file_lock call ↵Trond Myklebust1-0/+6
fl_release_private Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-05-05[PATCH] make some things staticAdrian Bunk1-3/+3
This patch makes some needlessly global identifiers static. Signed-off-by: Adrian Bunk <bunk@stusta.de> Acked-by: Arjan van de Ven <arjanv@infradead.org> Acked-by: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds1-0/+2212
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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