- 28 5月, 2014 1 次提交
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由 Al Viro 提交于
It can happen only when dentry_kill() is called with unlock_on_failure equal to 0 - other callers had dentry pinned until the moment they've got ->d_lock and DCACHE_DENTRY_KILLED is set only after lockref_mark_dead(). IOW, only one of three call sites of dentry_kill() might end up reaching that code. Just move it there. Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 04 5月, 2014 3 次提交
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由 Miklos Szeredi 提交于
Since now the shrink list is private and nobody can free the dentry while it is on the shrink list, we can remove RCU protection from this. Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
Start with shrink_dcache_parent(), then scan what remains. First of all, BUG() is very much an overkill here; we are holding ->s_umount, and hitting BUG() means that a lot of interesting stuff will be hanging after that point (sync(2), for example). Moreover, in cases when there had been more than one leak, we'll be better off reporting all of them. And more than just the last component of pathname - %pd is there for just such uses... That was the last user of dentry_lru_del(), so kill it off... Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
If we find something already on a shrink list, just increment data->found and do nothing else. Loops in shrink_dcache_parent() and check_submounts_and_drop() will do the right thing - everything we did put into our list will be evicted and if there had been nothing, but data->found got non-zero, well, we have somebody else shrinking those guys; just try again. Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 01 5月, 2014 5 次提交
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由 Al Viro 提交于
If the victim in on the shrink list, don't remove it from there. If shrink_dentry_list() manages to remove it from the list before we are done - fine, we'll just free it as usual. If not - mark it with new flag (DCACHE_MAY_FREE) and leave it there. Eventually, shrink_dentry_list() will get to it, remove the sucker from shrink list and call dentry_kill(dentry, 0). Which is where we'll deal with freeing. Since now dentry_kill(dentry, 0) may happen after or during dentry_kill(dentry, 1), we need to recognize that (by seeing DCACHE_DENTRY_KILLED already set), unlock everything and either free the sucker (in case DCACHE_MAY_FREE has been set) or leave it for ongoing dentry_kill(dentry, 1) to deal with. 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
The part of old d_free() that dealt with actual freeing of dentry. Taken out of dentry_kill() into a separate function. 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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- 20 4月, 2014 1 次提交
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由 Al Viro 提交于
in non-lazy walk we need to be careful about dentry switching from negative to positive - both ->d_flags and ->d_inode are updated, and in some places we might see only one store. The cases where dentry has been obtained by dcache lookup with ->i_mutex held on parent are safe - ->d_lock and ->i_mutex provide all the barriers we need. However, there are several places where we run into trouble: * do_last() fetches ->d_inode, then checks ->d_flags and assumes that inode won't be NULL unless d_is_negative() is true. Race with e.g. creat() - we might have fetched the old value of ->d_inode (still NULL) and new value of ->d_flags (already not DCACHE_MISS_TYPE). Lin Ming has observed and reported the resulting oops. * a bunch of places checks ->d_inode for being non-NULL, then checks ->d_flags for "is it a symlink". Race with symlink(2) in case if our CPU sees ->d_inode update first - we see non-NULL there, but ->d_flags still contains DCACHE_MISS_TYPE instead of DCACHE_SYMLINK_TYPE. Result: false negative on "should we follow link here?", with subsequent unpleasantness. Cc: stable@vger.kernel.org # 3.13 and 3.14 need that one Reported-and-tested-by: NLin Ming <minggr@gmail.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 01 4月, 2014 1 次提交
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由 Miklos Szeredi 提交于
If flags contain RENAME_EXCHANGE then exchange source and destination files. There's no restriction on the type of the files; e.g. a directory can be exchanged with a symlink. Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz> Reviewed-by: NJan Kara <jack@suse.cz> Reviewed-by: NJ. Bruce Fields <bfields@redhat.com>
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- 23 3月, 2014 1 次提交
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由 Al Viro 提交于
In all callchains leading to prepend_name(), the value left in *buflen is eventually discarded unused if prepend_name() has returned a negative. So we are free to do what prepend() does, and subtract from *buflen *before* checking for underflow (which turns into checking the sign of subtraction result, of course). Cc: stable@vger.kernel.org Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 16 3月, 2014 1 次提交
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由 David Herrmann 提交于
Our current DRM design uses a single address_space for all users of the same DRM device. However, there is no way to create an anonymous address_space without an underlying inode. Therefore, we wait for the first ->open() callback on a registered char-dev and take-over the inode of the char-dev. This worked well so far, but has several drawbacks: - We screw with FS internals and rely on some non-obvious invariants like inode->i_mapping being the same as inode->i_data for char-devs. - We don't have any address_space prior to the first ->open() from user-space. This leads to ugly fallback code and we cannot allocate global objects early. As pointed out by Al-Viro, fs/anon_inode.c is *not* supposed to be used by drivers for anonymous inode-allocation. Therefore, this patch follows the proposed alternative solution and adds a pseudo filesystem mount-point to DRM. We can then allocate private inodes including a private address_space for each DRM device at initialization time. Note that we could use: sysfs_get_inode(sysfs_mnt->mnt_sb, drm_device->dev->kobj.sd); to get access to the underlying sysfs-inode of a "struct device" object. However, most of this information is currently hidden and it's not clear whether this address_space is suitable for driver access. Thus, unless linux allows anonymous address_space objects or driver-core provides a public inode per device, we're left with our own private internal mount point. Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
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- 27 1月, 2014 1 次提交
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由 Al Viro 提交于
* we need to save the starting point for restarts * reject pathologically short buffers outright Spotted-by: NDenys Vlasenko <dvlasenk@redhat.com> Spotted-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 26 1月, 2014 1 次提交
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由 Eric W. Biederman 提交于
In commit 232d2d60 Author: Waiman Long <Waiman.Long@hp.com> Date: Mon Sep 9 12:18:13 2013 -0400 dcache: Translating dentry into pathname without taking rename_lock The __dentry_path locking was changed and the variable error was intended to be moved outside of the loop. Unfortunately the inner declaration of error was not removed. Resulting in a version of __dentry_path that will never return an error. Remove the problematic inner declaration of error and allow __dentry_path to return errors once again. Cc: stable@vger.kernel.org Cc: Waiman Long <Waiman.Long@hp.com> Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 13 12月, 2013 1 次提交
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由 Will Deacon 提交于
When explicitly hashing the end of a string with the word-at-a-time interface, we have to be careful which end of the word we pick up. On big-endian CPUs, the upper-bits will contain the data we're after, so ensure we generate our masks accordingly (and avoid hashing whatever random junk may have been sitting after the string). This patch adds a new dcache helper, bytemask_from_count, which creates a mask appropriate for the CPU endianness. Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: NWill Deacon <will.deacon@arm.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 27 11月, 2013 1 次提交
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由 Eric W. Biederman 提交于
Aditya Kali (adityakali@google.com) wrote: > Commit bf056bfa: > "proc: Fix the namespace inode permission checks." converted > the namespace files into symlinks. The same commit changed > the way namespace bind mounts appear in /proc/mounts: > $ mount --bind /proc/self/ns/ipc /mnt/ipc > Originally: > $ cat /proc/mounts | grep ipc > proc /mnt/ipc proc rw,nosuid,nodev,noexec 0 0 > > After commit bf056bfa: > $ cat /proc/mounts | grep ipc > proc ipc:[4026531839] proc rw,nosuid,nodev,noexec 0 0 > > This breaks userspace which expects the 2nd field in > /proc/mounts to be a valid path. The symlink /proc/<pid>/ns/{ipc,mnt,net,pid,user,uts} point to dentries allocated with d_alloc_pseudo that we can mount, and that have interesting names printed out with d_dname. When these files are bind mounted /proc/mounts is not currently displaying the mount point correctly because d_dname is called instead of just displaying the path where the file is mounted. Solve this by adding an explicit check to distinguish mounted pseudo inodes and unmounted pseudo inodes. Unmounted pseudo inodes always use mount of their filesstem as the mnt_root in their path making these two cases easy to distinguish. CC: stable@vger.kernel.org Acked-by: NSerge Hallyn <serge.hallyn@canonical.com> Reported-by: NAditya Kali <adityakali@google.com> Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
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- 16 11月, 2013 3 次提交
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由 Al Viro 提交于
There used to be a bunch of tree-walkers in dcache.c, all alike. try_to_ascend() had been introduced to abstract a piece of logics duplicated in all of them. These days all these tree-walkers are implemented via the same iterator (d_walk()), which is the only remaining caller of try_to_ascend(), so let's fold it back... Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
D_HASH{MASK,BITS} are used once each, both in the same function (d_hash()). At this point they are actively misguiding - they imply that values are compiler constants, which is no longer true. 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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- 13 11月, 2013 2 次提交
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由 Al Viro 提交于
... and equivalent is needed in 3.12; it's broken there as well Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Li Zhong 提交于
Signed-off-by: NLi Zhong <zhong@linux.vnet.ibm.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 09 11月, 2013 7 次提交
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由 J. Bruce Fields 提交于
DCACHE_DISCONNECTED should not be cleared until we're sure the dentry is connected all the way up to the root of the filesystem. It *shouldn't* be cleared as soon as the dentry is connected to a parent. That will cause bugs at least on exportable filesystems. Acked-by: NChristoph Hellwig <hch@infradead.org> Signed-off-by: NJ. Bruce Fields <bfields@redhat.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 J. Bruce Fields 提交于
I can't for the life of me see any reason why anyone should care whether a dentry that is never hooked into the dentry cache would need DCACHE_DISCONNECTED set. This originates from 4b936885 "fs: improve scalability of pseudo filesystems", which probably just made the false assumption the DCACHE_DISCONNECTED was meant to be set on anything not connected to a parent somehow. So this is just confusing. Ideally the only uses of DCACHE_DISCONNECTED would be in the filehandle-lookup code, which needs it to ensure dentries are connected into the dentry tree before use. I left d_alloc_pseudo there even though it's now equivalent to __d_alloc(), just on the theory the name is better documentation of its intended use outside dcache.c. Cc: Nick Piggin <npiggin@kernel.dk> Acked-by: NChristoph Hellwig <hch@infradead.org> Signed-off-by: NJ. Bruce Fields <bfields@redhat.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 J. Bruce Fields 提交于
Every hashed dentry is either hashed in the dentry_hashtable, or a superblock's s_anon list. __d_drop() assumes it can determine which is the case by checking DCACHE_DISCONNECTED; this is not true. It is true that when DCACHE_DISCONNECTED is cleared, the dentry is not only hashed on dentry_hashtable, but is fully connected to its parents back to the root. But the converse is *not* true: fs/exportfs/expfs.c:reconnect_path() attempts to connect a directory (found by filehandle lookup) back to root by ascending to parents and performing lookups one at a time. It does not clear DCACHE_DISCONNECTED until it's done, and that is not at all an atomic process. In particular, it is possible for DCACHE_DISCONNECTED to be set on a dentry which is hashed on the dentry_hashtable. Instead, use IS_ROOT() to check which hash chain a dentry is on. This *does* work: Dentries are hashed only by: - d_obtain_alias, which adds an IS_ROOT() dentry to sb_anon. - __d_rehash, called by _d_rehash: hashes to the dentry's parent, and all callers of _d_rehash appear to have d_parent set to a "real" parent. - __d_rehash, called by __d_move: rehashes the moved dentry to hash chain determined by target, and assigns target's d_parent to its d_parent, before dropping the dentry's d_lock. Therefore I believe it's safe for a holder of a dentry's d_lock to assume that it is hashed on sb_anon if and only if IS_ROOT(dentry) is true. I believe the incorrect assumption about DCACHE_DISCONNECTED was originally introduced by ceb5bdc2 "fs: dcache per-bucket dcache hash locking". Also add a comment while we're here. Cc: Nick Piggin <npiggin@kernel.dk> Acked-by: NChristoph Hellwig <hch@infradead.org> Reviewed-by: NNeilBrown <neilb@suse.de> Signed-off-by: NJ. Bruce Fields <bfields@redhat.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 David Howells 提交于
Put a type field into struct dentry::d_flags to indicate if the dentry is one of the following types that relate particularly to pathwalk: Miss (negative dentry) Directory "Automount" directory (defective - no i_op->lookup()) Symlink Other (regular, socket, fifo, device) The type field is set to one of the first five types on a dentry by calls to __d_instantiate() and d_obtain_alias() from information in the inode (if one is given). The type is cleared by dentry_unlink_inode() when it reconstitutes an existing dentry as a negative dentry. Accessors provided are: d_set_type(dentry, type) d_is_directory(dentry) d_is_autodir(dentry) d_is_symlink(dentry) d_is_file(dentry) d_is_negative(dentry) d_is_positive(dentry) A bunch of checks in pathname resolution switched to those. Signed-off-by: NDavid Howells <dhowells@redhat.com> 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
* RCU-delayed freeing of vfsmounts * vfsmount_lock replaced with a seqlock (mount_lock) * sequence number from mount_lock is stored in nameidata->m_seq and used when we exit RCU mode * new vfsmount flag - MNT_SYNC_UMOUNT. Set by umount_tree() when its caller knows that vfsmount will have no surviving references. * synchronize_rcu() done between unlocking namespace_sem in namespace_unlock() and doing pending mntput(). * new helper: legitimize_mnt(mnt, seq). Checks the mount_lock sequence number against seq, then grabs reference to mnt. Then it rechecks mount_lock again to close the race and either returns success or drops the reference it has acquired. The subtle point is that in case of MNT_SYNC_UMOUNT we can simply decrement the refcount and sod off - aforementioned synchronize_rcu() makes sure that final mntput() won't come until we leave RCU mode. We need that, since we don't want to end up with some lazy pathwalk racing with umount() and stealing the final mntput() from it - caller of umount() may expect it to return only once the fs is shut down and we don't want to break that. In other cases (i.e. with MNT_SYNC_UMOUNT absent) we have to do full-blown mntput() in case of mount_lock sequence number mismatch happening just as we'd grabbed the reference, but in those cases we won't be stealing the final mntput() from anything that would care. * mntput_no_expire() doesn't lock anything on the fast path now. Incidentally, SMP and UP cases are handled the same way - no ifdefs there. * normal pathname resolution does *not* do any writes to mount_lock. It does, of course, bump the refcounts of vfsmount and dentry in the very end, but that's it. Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
we have too many iterators in fs/dcache.c... Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 06 11月, 2013 1 次提交
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由 John Stultz 提交于
Currently seqlocks and seqcounts don't support lockdep. After running across a seqcount related deadlock in the timekeeping code, I used a less-refined and more focused variant of this patch to narrow down the cause of the issue. This is a first-pass attempt to properly enable lockdep functionality on seqlocks and seqcounts. Since seqcounts are used in the vdso gettimeofday code, I've provided non-lockdep accessors for those needs. I've also handled one case where there were nested seqlock writers and there may be more edge cases. Comments and feedback would be appreciated! Signed-off-by: NJohn Stultz <john.stultz@linaro.org> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Li Zefan <lizefan@huawei.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: netdev@vger.kernel.org Link: http://lkml.kernel.org/r/1381186321-4906-3-git-send-email-john.stultz@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 01 11月, 2013 1 次提交
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由 Linus Torvalds 提交于
We do not want to dirty the dentry->d_flags cacheline in dput() just to set the DCACHE_REFERENCED flag when it is already set in the common case anyway. This way the first cacheline of the dentry (which contains the RCU lookup information etc) can stay shared among multiple CPU's. This finishes off some of the details of all the scalability patches merged during the merge window. Also don't mark dentry_kill() for inlining, since it's the uncommon path and inlining it just makes the common path slower due to extra function entry/exit overhead. Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 25 10月, 2013 2 次提交
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由 Miklos Szeredi 提交于
...which just returns -EBUSY if a directory alias would be created. This is to be used by fuse mkdir to make sure that a buggy or malicious userspace filesystem doesn't do anything nasty. Previously fuse used a private mutex for this purpose, which can now go away. Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 22 10月, 2013 1 次提交
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由 Randy Dunlap 提交于
Move kernel-doc notation to immediately before its function to eliminate kernel-doc warnings introduced by commit db14fc3a ("vfs: add d_walk()") Warning(fs/dcache.c:1343): No description found for parameter 'data' Warning(fs/dcache.c:1343): No description found for parameter 'dentry' Warning(fs/dcache.c:1343): Excess function parameter 'parent' description in 'check_mount' Signed-off-by: NRandy Dunlap <rdunlap@infradead.org> Cc: Miklos Szeredi <mszeredi@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 15 9月, 2013 1 次提交
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由 Linus Torvalds 提交于
Sedat points out that I transposed some letters in "LRU" and wrote "RLU" instead in one of the new comments explaining the flow. Let's just fix it. Reported-by: NSedat Dilek <sedat.dilek@jpberlin.de> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 14 9月, 2013 1 次提交
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由 Linus Torvalds 提交于
The LRU list changes interacted badly with our nr_dentry_unused accounting, and even worse with the new DCACHE_LRU_LIST bit logic. This introduces helper functions to make sure everything follows the proper dcache d_lru list rules: the dentry cache is complicated by the fact that some of the hotpaths don't even want to look at the LRU list at all, and the fact that we use the same list entry in the dentry for both the LRU list and for our temporary shrinking lists when removing things from the LRU. The helper functions temporarily have some extra sanity checking for the flag bits that have to match the current LRU state of the dentry. We'll remove that before the final 3.12 release, but considering how easy it is to get wrong, this first cleanup version has some very particular sanity checking. Acked-by: NAl Viro <viro@zeniv.linux.org.uk> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 13 9月, 2013 4 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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