- 13 9月, 2013 6 次提交
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由 Linus Torvalds 提交于
This avoids the spinlocks and refcounts in the d_path() sequence too (used by /proc and various other entities). See commit 8b19e341 for the equivalent getcwd() system call path. And unlike getcwd(), d_path() doesn't copy the result to user space, so I don't need to fear _that_ particular bug happening again. Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Linus Torvalds 提交于
It's a pathname. It should use the pathname allocators and deallocators, and PATH_MAX instead of PAGE_SIZE. Never mind that the two are commonly the same. With this, the allocations scale up nicely too, and I can do getcwd() system calls at a rate of about 300M/s, with no lock contention anywhere. Of course, nobody sane does that, especially since getcwd() is traditionally a very slow operation in Unix. But this was also the simplest way to benchmark the prepend_path() improvements by Waiman, and once I saw the profiles I couldn't leave it well enough alone. But apart from being an performance improvement (from using per-cpu slab allocators instead of the raw page allocator), it's actually a valid and real cleanup. Signed-off-by: NLinus "OCD" Torvalds <torvalds@linux-foundation.org>
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由 Linus Torvalds 提交于
Oops. That wasn't very smart. We don't actually need the RCU lock any more by the time we copy the cwd string to user space, but I had stupidly surrounded the whole thing with it. Introduced by commit 8b19e341 ("vfs: make getcwd() get the root and pwd path under rcu") Is-a-big-hairy-idiot: Linus Torvalds <torvalds@linux-foundation.org>
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由 Linus Torvalds 提交于
This allows us to skip all the crazy spinlocks and reference count updates, and instead use the fs sequence read-lock to get an atomic snapshot of the root and cwd information. We might want to make the rule that "prepend_path()" is always called with the RCU lock held, but the RCU lock nests fine and this is the minimal fix. Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Linus Torvalds 提交于
Let's not pollute the include files with inline functions that are only used in a single place. Especially not if we decide we might want to change the semantics of said function to make it more efficient.. Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Waiman Long 提交于
This patch modifies read_seqbegin_or_lock() and need_seqretry() to use newly introduced read_seqlock_excl() and read_sequnlock_excl() primitives so that they won't change the sequence number even if they fall back to take the lock. This is OK as no change to the protected data structure is being made. It will prevent one fallback to lock taking from cascading into a series of lock taking reducing performance because of the sequence number change. It will also allow other sequence readers to go forward while an exclusive reader lock is taken. This patch also updates some of the inaccurate comments in the code. Signed-off-by: NWaiman Long <Waiman.Long@hp.com> To: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 10 9月, 2013 2 次提交
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由 Al Viro 提交于
Separate "check if we need to retry" from "unlock if we are done and had seq_writelock"; that allows to use these guys in d_walk(), where we need to recheck every time we ascend back to parent, but do *not* want to unlock until the very end. Lift rcu_read_lock/rcu_read_unlock out into callers. Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Waiman Long 提交于
When running the AIM7's short workload, Linus' lockref patch eliminated most of the spinlock contention. However, there were still some left: 8.46% reaim [kernel.kallsyms] [k] _raw_spin_lock |--42.21%-- d_path | proc_pid_readlink | SyS_readlinkat | SyS_readlink | system_call | __GI___readlink | |--40.97%-- sys_getcwd | system_call | __getcwd The big one here is the rename_lock (seqlock) contention in d_path() and the getcwd system call. This patch will eliminate the need to take the rename_lock while translating dentries into the full pathnames. The need to take the rename_lock is to make sure that no rename operation can be ongoing while the translation is in progress. However, only one thread can take the rename_lock thus blocking all the other threads that need it even though the translation process won't make any change to the dentries. This patch will replace the writer's write_seqlock/write_sequnlock sequence of the rename_lock of the callers of the prepend_path() and __dentry_path() functions with the reader's read_seqbegin/read_seqretry sequence within these 2 functions. As a result, the code will have to retry if one or more rename operations had been performed. In addition, RCU read lock will be taken during the translation process to make sure that no dentries will go away. To prevent live-lock from happening, the code will switch back to take the rename_lock if read_seqretry() fails for three times. To further reduce spinlock contention, this patch does not take the dentry's d_lock when copying the filename from the dentries. Instead, it treats the name pointer and length as unreliable and just copy the string byte-by-byte over until it hits a null byte or the end of string as specified by the length. This should avoid stepping into invalid memory address. The error cases are left to be handled by the sequence number check. The following code re-factoring are also made: 1. Move prepend('/') into prepend_name() to remove one conditional check. 2. Move the global root check in prepend_path() back to the top of the while loop. With this patch, the _raw_spin_lock will now account for only 1.2% of the total CPU cycles for the short workload. This patch also has the effect of reducing the effect of running perf on its profile since the perf command itself can be a heavy user of the d_path() function depending on the complexity of the workload. When taking the perf profile of the high-systime workload, the amount of spinlock contention contributed by running perf without this patch was about 16%. With this patch, the spinlock contention caused by the running of perf will go away and we will have a more accurate perf profile. Signed-off-by: NWaiman Long <Waiman.Long@hp.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 09 9月, 2013 2 次提交
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由 Linus Torvalds 提交于
This simplifies the RCU to refcounting code in particular. I was originally intending to leave this for later, but walking through all the dput() logic (see previous commit), I realized that the dput() "might_sleep()" check was misleadingly weak. And I removed it as misleading, both for performance profiling and for debugging. However, the might_sleep() debugging case is actually true: the final dput() can indeed sleep, if the inode of the dentry that you are releasing ends up sleeping at iput time (see dentry_iput()). So the problem with the might_sleep() in dput() wasn't that it wasn't true, it was that it wasn't actually testing and triggering on the interesting case. In particular, just about *any* dput() can indeed sleep, if you happen to race with another thread deleting the file in question, and you then lose the race to the be the last dput() for that file. But because it's a very rare race, the debugging code would never trigger it in practice. Why is this problematic? The new d_rcu_to_refcount() (see commit 15570086: "vfs: reimplement d_rcu_to_refcount() using lockref_get_or_lock()") does a dput() for the failure case, and it does it under the RCU lock. So potentially sleeping really is a bug. But there's no way I'm going to fix this with the previous complicated "lockref_get_or_lock()" interface. And rather than revert to the old and crufty nested dentry locking code (which did get this right by delaying the reference count updates until they were verified to be safe), let's make forward progress. Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Linus Torvalds 提交于
This is me being a bit OCD after all the dentry optimization work this merge window: profiles end up showing 'dput()' as a rather expensive operation, and there were two unrelated bad reasons for that. The first reason was reading d_lockref.count for debugging purposes, which touches the lockref cacheline (for reads) before really need to. More importantly, the debugging test in question is _wrong_, and has hidden bugs. It's true that we can only sleep when the count goes down to zero, but the test as-is hides the much more subtle bug that happens if we race with somebody else deleting the file. Anyway we _will_ touch that cacheline, but let's do it for a write and in the right routine (ie in "lockref_put_or_lock()") which annotates the costs better. So remove the misleading debug code. The other was an unnecessary access to the cacheline that contains the d_lru list, just to check whether we already were on the LRU list or not. This is exactly what we have d_flags for, so that we can avoid touching extra cache lines for the common case. So just add another bit for "is this dentry on the LRU". Finally, mark the tests properly likely/unlikely, so that the common fast-paths are dense in the instruction stream. This makes the profiles look much saner. Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 06 9月, 2013 4 次提交
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由 Miklos Szeredi 提交于
We check submounts before doing d_drop() on a non-empty directory dentry in NFS (have_submounts()), but we do not exclude a racing mount. Nor do we prevent mounts to be added to the disconnected subtree using relative paths after the d_drop(). This patch fixes these issues by checking for unlinked (unhashed, non-root) ancestors before proceeding with the mount. This is done with rename seqlock taken for write and with ->d_lock grabbed on each ancestor in turn, including our dentry itself. This ensures that the only one of check_submounts_and_drop() or has_unlinked_ancestor() can succeed. Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Miklos Szeredi 提交于
We check submounts before doing d_drop() on a non-empty directory dentry in NFS (have_submounts()), but we do not exclude a racing mount. Process A: have_submounts() -> returns false Process B: mount() -> success Process A: d_drop() This patch prepares the ground for the fix by doing the following operations all under the same rename lock: have_submounts() shrink_dcache_parent() d_drop() This is actually an optimization since have_submounts() and shrink_dcache_parent() both traverse the same dentry tree separately. Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz> CC: David Howells <dhowells@redhat.com> CC: Steven Whitehouse <swhiteho@redhat.com> CC: Trond Myklebust <Trond.Myklebust@netapp.com> CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Miklos Szeredi 提交于
This one replaces three instances open coded tree walking (have_submounts, select_parent, d_genocide) with a common helper. In addition to slightly reducing the kernel size, this simplifies the callers and makes them less bug prone. Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Miklos Szeredi 提交于
It shouldn't matter when we decrement the refcount during the walk as long as we do it exactly once. Restructure d_genocide() to do the killing on entering the dentry instead of when leaving it. This helps creating a common helper for tree walking. Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 04 9月, 2013 1 次提交
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由 Yan, Zheng 提交于
The d_prune dentry operation is used to notify filesystem when VFS about to prune a hashed dentry from the dcache. There are three code paths that prune dentries: shrink_dcache_for_umount_subtree(), prune_dcache_sb() and d_prune_aliases(). For the d_prune_aliases() case, VFS unhashes the dentry first, then call the d_prune dentry operation. This confuses ceph_d_prune() (ceph uses the d_prune dentry operation to maintain a flag indicating whether the complete contents of a directory are in the dcache, pruning unhashed dentry does not affect dir's completeness) This patch fixes the issue by calling the d_prune dentry operation in d_prune_aliases(), before unhashing the dentry. Also make VFS only call the d_prune dentry operation for hashed dentry, to avoid calling the d_prune dentry operation twice when dentry is pruned by d_prune_aliases(). Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 03 9月, 2013 2 次提交
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由 Linus Torvalds 提交于
This moves __d_rcu_to_refcount() from <linux/dcache.h> into fs/namei.c and re-implements it using the lockref infrastructure instead. It also adds a lot of comments about what is actually going on, because turning a dentry that was looked up using RCU into a long-lived reference counted entry is one of the more subtle parts of the rcu walk. We also used to be _particularly_ subtle in unlazy_walk() where we re-validate both the dentry and its parent using the same sequence count. We used to do it by nesting the locks and then verifying the sequence count just once. That was silly, because nested locking is expensive, but the sequence count check is not. So this just re-validates the dentry and the parent separately, avoiding the nested locking, and making the lockref lookup possible. Acked-by: NWaiman Long <waiman.long@hp.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Waiman Long 提交于
A valid parent pointer is always going to have a non-zero reference count, but if we look up the parent optimistically without locking, we have to protect against the (very unlikely) race against renaming changing the parent from under us. We do that by using lockref_get_not_zero(), and then re-checking the parent pointer after getting a valid reference. [ This is a re-implementation of a chunk from the original patch by Waiman Long: "dcache: Enable lockless update of dentry's refcount". I've completely rewritten the patch-series and split it up, but I'm attributing this part to Waiman as it's close enough to his earlier patch - Linus ] Signed-off-by: NWaiman Long <Waiman.Long@hp.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 29 8月, 2013 1 次提交
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由 Waiman Long 提交于
This just replaces the dentry count/lock combination with the lockref structure that contains both a count and a spinlock, and does the mechanical conversion to use the lockref infrastructure. There are no semantic changes here, it's purely syntactic. The reference lockref implementation uses the spinlock exactly the same way that the old dcache code did, and the bulk of this patch is just expanding the internal "d_count" use in the dcache code to use "d_lockref.count" instead. This is purely preparation for the real change to make the reference count updates be lockless during the 3.12 merge window. [ As with the previous commit, this is a rewritten version of a concept originally from Waiman, so credit goes to him, blame for any errors goes to me. Waiman's patch had some semantic differences for taking advantage of the lockless update in dget_parent(), while this patch is intentionally a pure search-and-replace change with no semantic changes. - Linus ] Signed-off-by: NWaiman Long <Waiman.Long@hp.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 25 8月, 2013 1 次提交
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由 Al Viro 提交于
dynamic_dname() is both too much and too little for those - the output may be well in excess of 64 bytes dynamic_dname() assumes to be enough (thanks to ashmem feeding really long names to shmem_file_setup()) and vsnprintf() is an overkill for those guys. Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 29 6月, 2013 3 次提交
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由 Linus Torvalds 提交于
Instances either don't look at it at all (the majority of cases) or only want it to find the superblock (which can be had as dentry->d_sb). A few cases that want more are actually safe with dentry->d_inode - the only precaution needed is the check that it hadn't been replaced with NULL by rmdir() or by overwriting rename(), which case should be simply treated as cache miss. Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
the only remaining caller (in ncpfs) is guaranteed to return 0 - we only hit it if we'd just checked that there's no dentry with such name. Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 14 6月, 2013 1 次提交
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由 Steven Whitehouse 提交于
I've restricted atomic_open to only operate on regular files, although I still don't understand why atomic_open should not be possible also for directories on GFS2. That can always be added in later though, if it makes sense. The ->atomic_open function can be passed negative dentries, which in most cases means either ENOENT (->lookup) or a call to d_instantiate (->create). In the GFS2 case though, we need to actually perform the look up, since we do not know whether there has been a new inode created on another node. The look up calls d_splice_alias which then tries to rehash the dentry - so the solution here is to simply check for that in d_splice_alias. The same issue is likely to affect any other cluster filesystem implementing ->atomic_open Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "J. Bruce Fields" <bfields fieldses org> Cc: Jeff Layton <jlayton@redhat.com>
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- 05 5月, 2013 2 次提交
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由 Wei Yongjun 提交于
Using list_move() instead of list_del() + list_add(). Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Yan, Zheng 提交于
When pruning a dentry, its ancestor dentry can also be pruned. But the ancestor dentry does not go through dput(), so it does not get put on the dentry LRU. Hence associating d_prune with removing the dentry from the LRU is the wrong. The fix is remove dentry_lru_prune(). Call file system's d_prune() callback directly when pruning dentries. Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 01 5月, 2013 1 次提交
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由 Greg Thelen 提交于
Call cond_resched() in shrink_dcache_parent() to maintain interactivity. Before this patch: void shrink_dcache_parent(struct dentry * parent) { while ((found = select_parent(parent, &dispose)) != 0) shrink_dentry_list(&dispose); } select_parent() populates the dispose list with dentries which shrink_dentry_list() then deletes. select_parent() carefully uses need_resched() to avoid doing too much work at once. But neither shrink_dcache_parent() nor its called functions call cond_resched(). So once need_resched() is set select_parent() will return single dentry dispose list which is then deleted by shrink_dentry_list(). This is inefficient when there are a lot of dentry to process. This can cause softlockup and hurts interactivity on non preemptable kernels. This change adds cond_resched() in shrink_dcache_parent(). The benefit of this is that need_resched() is quickly cleared so that future calls to select_parent() are able to efficiently return a big batch of dentry. These additional cond_resched() do not seem to impact performance, at least for the workload below. Here is a program which can cause soft lockup if other system activity sets need_resched(). int main() { struct rlimit rlim; int i; int f[100000]; char buf[20]; struct timeval t1, t2; double diff; /* cleanup past run */ system("rm -rf x"); /* boost nfile rlimit */ rlim.rlim_cur = 200000; rlim.rlim_max = 200000; if (setrlimit(RLIMIT_NOFILE, &rlim)) err(1, "setrlimit"); /* make directory for files */ if (mkdir("x", 0700)) err(1, "mkdir"); if (gettimeofday(&t1, NULL)) err(1, "gettimeofday"); /* populate directory with open files */ for (i = 0; i < 100000; i++) { snprintf(buf, sizeof(buf), "x/%d", i); f[i] = open(buf, O_CREAT); if (f[i] == -1) err(1, "open"); } /* close some of the files */ for (i = 0; i < 85000; i++) close(f[i]); /* unlink all files, even open ones */ system("rm -rf x"); if (gettimeofday(&t2, NULL)) err(1, "gettimeofday"); diff = (((double)t2.tv_sec * 1000000 + t2.tv_usec) - ((double)t1.tv_sec * 1000000 + t1.tv_usec)); printf("done: %g elapsed\n", diff/1e6); return 0; } Signed-off-by: NGreg Thelen <gthelen@google.com> Signed-off-by: NDave Chinner <david@fromorbit.com> Cc: <stable@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 27 3月, 2013 1 次提交
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由 Al Viro 提交于
... lest we get livelocks between path_is_under() and d_path() and friends. The thing is, wrt fairness lglocks are more similar to rwsems than to rwlocks; it is possible to have thread B spin on attempt to take lock shared while thread A is already holding it shared, if B is on lower-numbered CPU than A and there's a thread C spinning on attempt to take the same lock exclusive. As the result, we need consistent ordering between vfsmount_lock (lglock) and rename_lock (seq_lock), even though everything that takes both is going to take vfsmount_lock only shared. Spotted-by: NBrad Spengler <spender@grsecurity.net> Cc: stable@vger.kernel.org Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 28 2月, 2013 1 次提交
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由 Sasha Levin 提交于
I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: NPeter Senna Tschudin <peter.senna@gmail.com> Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: NSasha Levin <sasha.levin@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 26 2月, 2013 2 次提交
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由 Jeff Layton 提交于
The following set of operations on a NFS client and server will cause server# mkdir a client# cd a server# mv a a.bak client# sleep 30 # (or whatever the dir attrcache timeout is) client# stat . stat: cannot stat `.': Stale NFS file handle Obviously, we should not be getting an ESTALE error back there since the inode still exists on the server. The problem is that the lookup code will call d_revalidate on the dentry that "." refers to, because NFS has FS_REVAL_DOT set. nfs_lookup_revalidate will see that the parent directory has changed and will try to reverify the dentry by redoing a LOOKUP. That of course fails, so the lookup code returns ESTALE. The problem here is that d_revalidate is really a bad fit for this case. What we really want to know at this point is whether the inode is still good or not, but we don't really care what name it goes by or whether the dcache is still valid. Add a new d_op->d_weak_revalidate operation and have complete_walk call that instead of d_revalidate. The intent there is to allow for a "weaker" d_revalidate that just checks to see whether the inode is still good. This is also gives us an opportunity to kill off the FS_REVAL_DOT special casing. [AV: changed method name, added note in porting, fixed confusion re having it possibly called from RCU mode (it won't be)] Cc: NeilBrown <neilb@suse.de> Signed-off-by: NJeff Layton <jlayton@redhat.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
* calling conventions change - ERR_PTR() is returned on ->d_hash() errors; NULL is just for dcache miss now. * exported, open-coded instances in ncpfs and cifs converted. Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 23 2月, 2013 4 次提交
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由 Al Viro 提交于
Its first argument is always non-root, while the second one is always root. Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Jeff Layton 提交于
The last caller was removed >2 years ago in commit 7b2a69ba. Signed-off-by: NJeff Layton <jlayton@redhat.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 21 12月, 2012 2 次提交
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由 NeilBrown 提交于
NFS appears to use d_obtain_alias() to create the root dentry rather than d_make_root. This can cause 'prepend_path()' to complain that the root has a weird name if an NFS filesystem is lazily unmounted. e.g. if "/mnt" is an NFS mount then { cd /mnt; umount -l /mnt ; ls -l /proc/self/cwd; } will cause a WARN message like WARNING: at /home/git/linux/fs/dcache.c:2624 prepend_path+0x1d7/0x1e0() ... Root dentry has weird name <> to appear in kernel logs. So change d_obtain_alias() to use "/" rather than "" as the anonymous name. Signed-off-by: NNeilBrown <neilb@suse.de> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Jeff Layton 提交于
The code that relied on that flag was ripped out of btrfs quite some time ago, and never added back. Josef indicated that he was going to take a different approach to the problem in btrfs, and that we could just eliminate this flag. Cc: Josef Bacik <jbacik@fusionio.com> Signed-off-by: NJeff Layton <jlayton@redhat.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 30 9月, 2012 1 次提交
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由 Miklos Szeredi 提交于
IBM reported a deadlock in select_parent(). This was found to be caused by taking rename_lock when already locked when restarting the tree traversal. There are two cases when the traversal needs to be restarted: 1) concurrent d_move(); this can only happen when not already locked, since taking rename_lock protects against concurrent d_move(). 2) racing with final d_put() on child just at the moment of ascending to parent; rename_lock doesn't protect against this rare race, so it can happen when already locked. Because of case 2, we need to be able to handle restarting the traversal when rename_lock is already held. This patch fixes all three callers of try_to_ascend(). IBM reported that the deadlock is gone with this patch. [ I rewrote the patch to be smaller and just do the "goto again" if the lock was already held, but credit goes to Miklos for the real work. - Linus ] Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: stable@vger.kernel.org Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 28 9月, 2012 1 次提交
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由 J. Bruce Fields 提交于
"Search list for X" sounds like you're trying to find X on a list. Signed-off-by: NJ. Bruce Fields <bfields@redhat.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 27 9月, 2012 1 次提交
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由 Alan Cox 提交于
Each iteration of d_delete we reload inode from dentry->d_inode and then call S_ISDIR(inode-i_mode), so inode cannot possibly be NULL shortly afterwards unless something went horribly wrong. Signed-off-by: NAlan Cox <alan@linux.intel.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 19 9月, 2012 1 次提交
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由 Miklos Szeredi 提交于
IBM reported a soft lockup after applying the fix for the rename_lock deadlock. Commit c83ce989 ("VFS: Fix the nfs sillyrename regression in kernel 2.6.38") was found to be the culprit. The nfs sillyrename fix used DCACHE_DISCONNECTED to indicate that the dentry was killed. This flag can be set on non-killed dentries too, which results in infinite retries when trying to traverse the dentry tree. This patch introduces a separate flag: DCACHE_DENTRY_KILLED, which is only set in d_kill() and makes try_to_ascend() test only this flag. IBM reported successful test results with this patch. Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: stable@vger.kernel.org Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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