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path: root/fs/autofs4/expire.c
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* autofs - remove autofs dentry mount checkDavid Jeffery2013-05-061-9/+0
| | | | | | | | | | | | | | | | | | | When checking if an autofs mount point is busy it isn't sufficient to only check if it's a mount point. For example, if the mount of an offset mountpoint in a tree is denied for this host by its export and the dentry becomes a process working directory the check incorrectly returns the mount as not in use at expire. This can happen since the default when mounting within a tree is nostrict, which means ingnore mount fails on mounts within the tree and continue. The nostrict option is meant to allow mounting in this case. Signed-off-by: David Jeffery <djeffery@redhat.com> Signed-off-by: Ian Kent <raven@themaw.net> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4 - dont clear DCACHE_NEED_AUTOMOUNT on rootless mountIan Kent2012-12-131-9/+0
| | | | | | | | | | | | | | | The DCACHE_NEED_AUTOMOUNT flag is cleared on mount and set on expire for autofs rootless multi-mount dentrys to prevent unnecessary calls to ->d_automount(). Since DCACHE_MANAGE_TRANSIT is always set on autofs dentrys ->d_managed() is always called so the check can be done in ->d_manage() without the need to change the flag. This still avoids unnecessary calls to ->d_automount(), adds negligible overhead and eliminates a seriously ugly check in the expire code. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4 - fix expire checkIan Kent2012-08-171-5/+0
| | | | | | | | | | | | | | | | | | | | | | In some cases when an autofs indirect mount is contained in a file system that is marked as shared (such as when systemd does the equivalent of "mount --make-rshared /" early in the boot), mounts stop expiring. When this happens the first expiry check on a mountpoint dentry in autofs_expire_indirect() sees a mountpoint dentry with a higher than minimal reference count. Consequently the dentry is condidered busy and the actual expiry check is never done. This particular check was originally meant as an optimisation to detect a path walk in progress but with the addition of rcu-walk it can be ineffective anyway. Removing the test allows automounts to expire again since the actual expire check doesn't rely on the dentry reference count. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4 - fix get_next_positive_subdir()Ian Kent2012-08-161-18/+13
| | | | | | | | | | | | | | | | | | Following a report of a crash during an automount expire I found that the locking in fs/autofs4/expire.c:get_next_positive_subdir() was wrong. Not only is the locking wrong but the function is more complex than it needs to be. The function is meant to calculate (and dget) the next entry in the list of directories contained in the root of an autofs mount point (an autofs indirect mount to be precise). The main problem was that the d_lock of the owner of the list was not being taken when walking the list, which lead to list corruption under load. The only other lock that needs to be taken is against the next dentry candidate so it can be checked for usability. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4 - fix lockdep splat in autofsSteven Rostedt2012-02-131-0/+2
| | | | | | | | | | | When recursing down the locks when traversing a tree/list in get_next_positive_dentry() or get_next_positive_subdir() a lock can change from being nested to being a parent which breaks lockdep. This patch tells lockdep about what we did. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4 - remove autofs4_lockIan Kent2011-03-241-8/+10
| | | | | | | | | | The autofs4_lock introduced by the rcu-walk changes has unnecessarily broad scope. The locking is better handled by the per-autofs super block lookup_lock. Signed-off-by: Ian Kent <raven@themaw.net> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4 - fix autofs4_expire_indirect() traversalIan Kent2011-03-241-1/+51
| | | | | | | | | The vfs-scale changes changed the traversal used in autofs4_expire_indirect() from a list to a depth first tree traversal which isn't right. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4 - fix dentry leak in autofs4_expire_direct()Ian Kent2011-03-241-4/+3
| | | | | | | | | There is a missing dput() when returning from autofs4_expire_direct() when we see that the dentry is already a pending mount. Signed-off-by: Ian Kent <raven@themaw.net> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4 - reinstate last used update on accessIan Kent2011-03-241-11/+2
| | | | | | | | | | | | | | When direct (and offset) mounts were introduced the the last used timeout could no longer be updated in ->d_revalidate(). This is because covered direct mounts would be followed over without calling the autofs file system. As a result the definition of the busyness check for all entries was changed to be "actually busy" being an open file or working directory within the automount. But now we have a call back in the follow so the last used update on any access can be re-instated. This requires DCACHE_MANAGE_TRANSIT to always be set. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4 - fix get_next_positive_dentry()Ian Kent2011-01-181-2/+2
| | | | | | | | | | | | | | The initialization condition in fs/autofs4/expire.c:get_next_positive_dentry() appears to be incorrect. If prev == NULL I believe that root should be returned. Further down, at the current dentry check for it being simple_positive() it looks like the d_lock for dentry p should be dropped instead of dentry ret, otherwise when p is assinged to ret we end up with no lock on p and a lost lock on ret, which leads to a deadlock. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: Add d_manage() dentry operationIan Kent2011-01-151-25/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch required a previous patch to add the ->d_automount() dentry operation. Add a function to use the newly defined ->d_manage() dentry operation for blocking during mount and expire. Whether the VFS calls the dentry operations d_automount() and d_manage() is controled by the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags. autofs uses the d_automount() operation to callback to user space to request mount operations and the d_manage() operation to block walks into mounts that are under construction or destruction. In order to prevent these functions from being called unnecessarily the DMANAGED_* flags are cleared for cases which would cause this. In the common case the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags are both set for dentrys waiting to be mounted. The DMANAGED_TRANSIT flag is cleared upon successful mount request completion and set during expire runs, both during the dentry expire check, and if selected for expire, is left set until a subsequent successful mount request completes. The exception to this is the so-called rootless multi-mount which has no actual mount at its base. In this case the DMANAGED_AUTOMOUNT flag is cleared upon successful mount request completion as well and set again after a successful expire. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: Add d_automount() dentry operationIan Kent2011-01-151-0/+6
| | | | | | | | | | | | | | Add a function to use the newly defined ->d_automount() dentry operation for triggering mounts instead of doing the user space callback in ->lookup() and ->d_revalidate(). Note, to be useful the subsequent patch to add the ->d_manage() dentry operation is also needed so the discussion of functionality is deferred to that patch. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Add a dentry op to allow processes to be held during pathwalk transitDavid Howells2011-01-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a dentry op (d_manage) to permit a filesystem to hold a process and make it sleep when it tries to transit away from one of that filesystem's directories during a pathwalk. The operation is keyed off a new dentry flag (DCACHE_MANAGE_TRANSIT). The filesystem is allowed to be selective about which processes it holds and which it permits to continue on or prohibits from transiting from each flagged directory. This will allow autofs to hold up client processes whilst letting its userspace daemon through to maintain the directory or the stuff behind it or mounted upon it. The ->d_manage() dentry operation: int (*d_manage)(struct path *path, bool mounting_here); takes a pointer to the directory about to be transited away from and a flag indicating whether the transit is undertaken by do_add_mount() or do_move_mount() skipping through a pile of filesystems mounted on a mountpoint. It should return 0 if successful and to let the process continue on its way; -EISDIR to prohibit the caller from skipping to overmounted filesystems or automounting, and to use this directory; or some other error code to return to the user. ->d_manage() is called with namespace_sem writelocked if mounting_here is true and no other locks held, so it may sleep. However, if mounting_here is true, it may not initiate or wait for a mount or unmount upon the parameter directory, even if the act is actually performed by userspace. Within fs/namei.c, follow_managed() is extended to check with d_manage() first on each managed directory, before transiting away from it or attempting to automount upon it. follow_down() is renamed follow_down_one() and should only be used where the filesystem deliberately intends to avoid management steps (e.g. autofs). A new follow_down() is added that incorporates the loop done by all other callers of follow_down() (do_add/move_mount(), autofs and NFSD; whilst AFS, NFS and CIFS do use it, their use is removed by converting them to use d_automount()). The new follow_down() calls d_manage() as appropriate. It also takes an extra parameter to indicate if it is being called from mount code (with namespace_sem writelocked) which it passes to d_manage(). follow_down() ignores automount points so that it can be used to mount on them. __follow_mount_rcu() is made to abort rcu-walk mode if it hits a directory with DCACHE_MANAGE_TRANSIT set on the basis that we're probably going to have to sleep. It would be possible to enter d_manage() in rcu-walk mode too, and have that determine whether to abort or not itself. That would allow the autofs daemon to continue on in rcu-walk mode. Note that DCACHE_MANAGE_TRANSIT on a directory should be cleared when it isn't required as every tranist from that directory will cause d_manage() to be invoked. It can always be set again when necessary. ========================== WHAT THIS MEANS FOR AUTOFS ========================== Autofs currently uses the lookup() inode op and the d_revalidate() dentry op to trigger the automounting of indirect mounts, and both of these can be called with i_mutex held. autofs knows that the i_mutex will be held by the caller in lookup(), and so can drop it before invoking the daemon - but this isn't so for d_revalidate(), since the lock is only held on _some_ of the code paths that call it. This means that autofs can't risk dropping i_mutex from its d_revalidate() function before it calls the daemon. The bug could manifest itself as, for example, a process that's trying to validate an automount dentry that gets made to wait because that dentry is expired and needs cleaning up: mkdir S ffffffff8014e05a 0 32580 24956 Call Trace: [<ffffffff885371fd>] :autofs4:autofs4_wait+0x674/0x897 [<ffffffff80127f7d>] avc_has_perm+0x46/0x58 [<ffffffff8009fdcf>] autoremove_wake_function+0x0/0x2e [<ffffffff88537be6>] :autofs4:autofs4_expire_wait+0x41/0x6b [<ffffffff88535cfc>] :autofs4:autofs4_revalidate+0x91/0x149 [<ffffffff80036d96>] __lookup_hash+0xa0/0x12f [<ffffffff80057a2f>] lookup_create+0x46/0x80 [<ffffffff800e6e31>] sys_mkdirat+0x56/0xe4 versus the automount daemon which wants to remove that dentry, but can't because the normal process is holding the i_mutex lock: automount D ffffffff8014e05a 0 32581 1 32561 Call Trace: [<ffffffff80063c3f>] __mutex_lock_slowpath+0x60/0x9b [<ffffffff8000ccf1>] do_path_lookup+0x2ca/0x2f1 [<ffffffff80063c89>] .text.lock.mutex+0xf/0x14 [<ffffffff800e6d55>] do_rmdir+0x77/0xde [<ffffffff8005d229>] tracesys+0x71/0xe0 [<ffffffff8005d28d>] tracesys+0xd5/0xe0 which means that the system is deadlocked. This patch allows autofs to hold up normal processes whilst the daemon goes ahead and does things to the dentry tree behind the automouter point without risking a deadlock as almost no locks are held in d_manage() and none in d_automount(). Signed-off-by: David Howells <dhowells@redhat.com> Was-Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs: dcache remove d_mountedNick Piggin2011-01-071-2/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rather than keep a d_mounted count in the dentry, set a dentry flag instead. The flag can be cleared by checking the hash table to see if there are any mounts left, which is not time critical because it is performed at detach time. The mounted state of a dentry is only used to speculatively take a look in the mount hash table if it is set -- before following the mount, vfsmount lock is taken and mount re-checked without races. This saves 4 bytes on 32-bit, nothing on 64-bit but it does provide a hole I might use later (and some configs have larger than 32-bit spinlocks which might make use of the hole). Autofs4 conversion and changelog by Ian Kent <raven@themaw.net>: In autofs4, when expring direct (or offset) mounts we need to ensure that we block user path walks into the autofs mount, which is covered by another mount. To do this we clear the mounted status so that follows stop before walking into the mount and are essentially blocked until the expire is completed. The automount daemon still finds the correct dentry for the umount due to the follow mount logic in fs/autofs4/root.c:autofs4_follow_link(), which is set as an inode operation for direct and offset mounts only and is called following the lookup that stopped at the covered mount. At the end of the expire the covering mount probably has gone away so the mounted status need not be restored. But we need to check this and only restore the mounted status if the expire failed. XXX: autofs may not work right if we have other mounts go over the top of it? Signed-off-by: Nick Piggin <npiggin@kernel.dk>
* fs: dcache remove dcache_lockNick Piggin2011-01-071-5/+5
| | | | | | dcache_lock no longer protects anything. remove it. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
* fs: dcache scale subdirsNick Piggin2011-01-071-67/+60
| | | | | | | | | | | | Protect d_subdirs and d_child with d_lock, except in filesystems that aren't using dcache_lock for these anyway (eg. using i_mutex). Note: if we change the locking rule in future so that ->d_child protection is provided only with ->d_parent->d_lock, it may allow us to reduce some locking. But it would be an exception to an otherwise regular locking scheme, so we'd have to see some good results. Probably not worthwhile. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
* fs: dcache scale d_unhashedNick Piggin2011-01-071-5/+16
| | | | | | | Protect d_unhashed(dentry) condition with d_lock. This means keeping DCACHE_UNHASHED bit in synch with hash manipulations. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
* fs: dcache scale dentry refcountNick Piggin2011-01-071-4/+4
| | | | | | | | Make d_count non-atomic and protect it with d_lock. This allows us to ensure a 0 refcount dentry remains 0 without dcache_lock. It is also fairly natural when we start protecting many other dentry members with d_lock. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
* Revert "autofs4: always use lookup for lookup"Al Viro2010-03-031-5/+1
| | | | | | | | | | This reverts commit 213614d583748d00967a91cacd656f417efb36ce. Alas, ->d_revalidate() can't rely on ->lookup() finishing what it's started; if d_alloc() in do_lookup() fails, we are not going to call ->lookup() at all. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: always use lookup for lookupIan Kent2009-12-161-1/+5
| | | | | | | | | | | | | | | | | We need to be able to cope with the directory mutex being held during ->d_revalidate() in some cases, but not all cases, and not necessarily by us. Because we need to release the mutex when we call back to the daemon to do perform a mount we must be sure that it is us who holds the mutex so we must redirect mount requests to ->lookup() if the mutex is held. Signed-off-by: Ian Kent <raven@themaw.net> Cc: Sage Weil <sage@newdream.net> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Andreas Dilger <adilger@sun.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Yehuda Saheh <yehuda@newdream.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: use autofs_info for pending flagIan Kent2009-12-161-1/+1
| | | | | | | | | | | | | | | | Eliminate the use of the d_lock spin lock by using the autofs super block info spin lock. This reduces the number of spin locks we use by one and makes the code for the following patch (to redirect ->d_revalidate() to ->lookup()) a little simpler. Signed-off-by: Ian Kent <raven@themaw.net> Cc: Sage Weil <sage@newdream.net> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Andreas Dilger <adilger@sun.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Yehuda Saheh <yehuda@newdream.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4 - fix missed case when changing to use struct pathIan Kent2009-08-311-1/+1
| | | | | | | | | In the recent change by Al Viro that changes verious subsystems to use "struct path" one case was missed in the autofs4 module which causes mounts to no longer expire. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* switch follow_down()Al Viro2009-06-111-8/+7
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: fix incorrect return in autofs4_mount_busy()Ian Kent2009-05-021-1/+3
| | | | | | | | Fix an obvious incorrect return status in autofs4_mount_busy(). Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: cleanup expire code duplicationIan Kent2009-04-011-10/+17
| | | | | | | | | | | A significant portion of the autofs_dev_ioctl_expire() and autofs4_expire_multi() functions is duplicated code. This patch cleans that up. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: make autofs type usage explicitIan Kent2009-01-061-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | - the type assigned at mount when no type is given is changed from 0 to AUTOFS_TYPE_INDIRECT. This was done because 0 and AUTOFS_TYPE_INDIRECT were being treated implicitly as the same type. - previously, an offset mount had it's type set to AUTOFS_TYPE_DIRECT|AUTOFS_TYPE_OFFSET but the mount control re-implementation needs to be able distinguish all three types. So this was changed to make the type setting explicit. - a type AUTOFS_TYPE_ANY was added for use by the re-implementation when checking if a given path is a mountpoint. It's not really a type as we use this to ask if a given path is a mountpoint in the autofs_dev_ioctl_ismountpoint() function. - functions to set and test the autofs mount types have been added to improve readability and make the type usage explicit. - the mount type is used from user space for the mount control re-implementtion so, for consistency, all the definitions have been moved to the user space include file include/linux/auto_fs4.h. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: correct offset mount expire checkIan Kent2008-11-061-4/+15
| | | | | | | | | | | | | When checking a directory tree in autofs_tree_busy() we can incorrectly decide that the tree isn't busy. This happens for the case of an active offset mount as autofs4_follow_mount() follows past the active offset mount, which has an open file handle used for expires, causing the file handle not to count toward the busyness check. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: add miscellaneous device for ioctlsIan Kent2008-10-161-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a miscellaneous device to the autofs4 module for routing ioctls. This provides the ability to obtain an ioctl file handle for an autofs mount point that is possibly covered by another mount. The actual problem with autofs is that it can't reconnect to existing mounts. Immediately one things of just adding the ability to remount autofs file systems would solve it, but alas, that can't work. This is because autofs direct mounts and the implementation of "on demand mount and expire" of nested mount trees have the file system mounted on top of the mount trigger dentry. To resolve this a miscellaneous device node for routing ioctl commands to these mount points has been implemented in the autofs4 kernel module and a library added to autofs. This provides the ability to open a file descriptor for these over mounted autofs mount points. Please refer to Documentation/filesystems/autofs4-mount-control.txt for a discussion of the problem, implementation alternatives considered and a description of the interface. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: build fix] Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: cleanup autofs mount type usageIan Kent2008-10-161-1/+1
| | | | | | | | | Usage of the AUTOFS_TYPE_* defines is a little confusing and appears inconsistent. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: reorganize expire pending wait function callsIan Kent2008-07-241-0/+29
| | | | | | | | | | This patch re-orgnirzes the checking for and waiting on active expires and elininates redundant checks. Signed-off-by: Ian Kent <raven@themaw.net> Cc: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: fix direct mount pending expire raceIan Kent2008-07-241-3/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For direct and offset type mounts that are covered by another mount we cannot check the AUTOFS_INF_EXPIRING flag during a path walk which leads to lookups walking into an expiring mount while it is being expired. For example, for the direct multi-mount map entry with a couple of offsets: /race/mm1 / <server1>:/<path1> /om1 <server2>:/<path2> /om2 <server1>:/<path3> an autofs trigger mount is mounted on /race/mm1 and when accessed it is over mounted and trigger mounts made for /race/mm1/om1 and /race/mm1/om2. So it isn't possible for path walks to see the expiring flag at all and they happily walk into the file system while it is expiring. When expiring these mounts follow_down() must stop at the autofs mount and all processes must block in the ->follow_link() method (except the daemon) until the expire is complete. This is done by decrementing the d_mounted field of the autofs trigger mount root dentry until the expire is completed. In ->follow_link() all processes wait on the expire and the mount following is completed for the daemon until the expire is complete. Signed-off-by: Ian Kent <raven@themaw.net> Cc: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: fix indirect mount pending expire raceIan Kent2008-07-241-11/+35
| | | | | | | | | | | | | | | | | The selection of a dentry for expiration and the setting of the AUTOFS_INF_EXPIRING flag isn't done atomically which can lead to lookups walking into an expiring mount. What happens is that an expire is initiated by the daemon and a dentry is selected for expire but, since there is no lock held between the selection and setting of the expiring flag, a process may find the flag clear and continue walking into the mount tree at the same time the daemon attempts the expire it. Signed-off-by: Ian Kent <raven@themaw.net> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs: path_{get,put}() cleanupsJan Blunck2008-05-011-1/+1
| | | | | | | | | | | Here are some more places where path_{get,put}() can be used instead of dput()/mntput() pair. Besides that it fixes a bug in autofs4_mount_busy() where mntput() was called before dput(). Signed-off-by: Jan Blunck <jblunck@suse.de> Cc: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: fix sparse warning in waitq.c:autofs4_expire_indirect()Ian Kent2008-05-011-13/+11
| | | | | | | | | | | | | | Re-order some code in expire.c:autofs4_expire_indirect() to avoid compile warning, reported by Harvey Harrison: CHECK fs/autofs4/expire.c fs/autofs4/expire.c:383:2: warning: context imbalance in 'autofs4_expire_indirect' - unexpected unlock Signed-off-by: Ian Kent <raven@themaw.net> Reviewed-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] autofs4: zero timeout prevents shutdownIan Kent2006-09-251-3/+3
| | | | | | | | | | | | | | If the timeout of an autofs mount is set to zero then umounts are disabled. This works fine, however the kernel module checks the expire timeout and goes no further if it is zero. This is not the right thing to do at shutdown as the module is passed an option to expire mounts regardless of their timeout setting. This patch allows autofs to honor the force expire option. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fs: use list_move()Akinobu Mita2006-06-261-2/+1
| | | | | | | | | | | | | | | | This patch converts the combination of list_del(A) and list_add(A, B) to list_move(A, B) under fs/. Cc: Ian Kent <raven@themaw.net> Acked-by: Joel Becker <joel.becker@oracle.com> Cc: Neil Brown <neilb@cse.unsw.edu.au> Cc: Hans Reiser <reiserfs-dev@namesys.com> Cc: Urban Widmark <urban@teststation.com> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Mark Fasheh <mark.fasheh@oracle.com> Signed-off-by: Akinobu Mita <mita@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs4: need to invalidate children on tree mount expireIan Kent2006-06-251-0/+6
| | | | | | | | | | | | | | | I've found a case where invalid dentrys in a mount tree, waiting to be cleaned up by d_invalidate, prevent the expected expire. In this case dentrys created during a lookup for which a mount fails or has no entry in the mount map contribute to the d_count of the parent dentry. These dentrys may not be invalidated prior to comparing the interanl usage count of valid autofs dentrys against the dentry d_count which makes a mount tree appear busy so it doesn't expire. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs4: follow_link missing functionalityIan Kent2006-03-271-4/+0
| | | | | | | | This functionality is also need for operation of autofs v5 direct mounts. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs4: change AUTOFS_TYP_* AUTOFS_TYPE_*Ian Kent2006-03-271-1/+1
| | | | | | Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs4: add v5 expire logicIan Kent2006-03-271-9/+87
| | | | | | | | | | This patch adds expire logic for autofs direct mounts. Signed-off-by: Ian Kent <raven@themaw.net> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs4: change may_umount* functions to booleanIan Kent2006-03-271-1/+1
| | | | | | | | | Change the functions may_umount and may_umount_tree to boolean functions to aid code readability. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs4: expire mounts that hold no (extra) references onlyIan Kent2006-03-271-14/+22
| | | | | | | | | | | | | | | | | | | | | | Alter the expire semantics that define how "busyness" is determined. Currently a last_used counter is updated on every revalidate from processes other than the mount owner process group. This patch changes that so that an expire candidate is busy only if it has a reference count greater than the expected minimum, such as when there is an open file or working directory in use. This method is the only way that busyness can be established for direct mounts within the new implementation. For consistency the expire semantic is made the same for all mounts. A side effect of the patch is that mounts which remain mounted unessessarily in the presence of some GUI programs that scan the filesystem should now expire. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs4: fix false negative return from expireIan Kent2006-03-271-9/+25
| | | | | | | | | | | | | | | Fix the case where an expire returns busy on a tree mount when it is in fact not busy. This case was overlooked when the patch to prevent the expiring away of "scaffolding" directories for tree mounts was applied. The problem arises when a tree of mounts is a member of a map with other keys. The current logic will not expire the tree if any other mount in the map is busy. The solution is to maintain a "minimum" use count for each autofs dentry and compare this to the actual dentry usage count during expire. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs4: simplify expire tree traversalIan Kent2006-03-271-62/+40
| | | | | | | | | | Simplify the expire tree traversal code by using a function from namespace.c to calculate the next entry in the top down tree traversals carried out during the expire operation. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs4: expire code readability cleanupIan Kent2006-03-271-28/+26
| | | | | | | | | | | | Change the names of the boolean functions autofs4_check_mount and autofs4_check_tree to autofs4_mount_busy and autofs4_tree_busy respectively and alters their return codes to suit in order to aid code readabilty. A couple of white space cleanups are included as well. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] shrink dentry structEric Dumazet2006-01-081-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some long time ago, dentry struct was carefully tuned so that on 32 bits UP, sizeof(struct dentry) was exactly 128, ie a power of 2, and a multiple of memory cache lines. Then RCU was added and dentry struct enlarged by two pointers, with nice results for SMP, but not so good on UP, because breaking the above tuning (128 + 8 = 136 bytes) This patch reverts this unwanted side effect, by using an union (d_u), where d_rcu and d_child are placed so that these two fields can share their memory needs. At the time d_free() is called (and d_rcu is really used), d_child is known to be empty and not touched by the dentry freeing. Lockless lookups only access d_name, d_parent, d_lock, d_op, d_flags (so the previous content of d_child is not needed if said dentry was unhashed but still accessed by a CPU because of RCU constraints) As dentry cache easily contains millions of entries, a size reduction is worth the extra complexity of the ugly C union. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Maneesh Soni <maneesh@in.ibm.com> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Ian Kent <raven@themaw.net> Cc: Paul Jackson <pj@sgi.com> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Neil Brown <neilb@cse.unsw.edu.au> Cc: James Morris <jmorris@namei.org> Cc: Stephen Smalley <sds@epoch.ncsc.mil> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs4: avoid panic on bind mount of autofs owned directoryIan Kent2005-06-211-4/+1
| | | | | | | | | | | While this is not a solution to bind and move mounts on autofs owned directories it is necessary to fix the trady error handling. At least it avoids the kernel panic I observed checking out bug #4589. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs4: tree race fixIan Kent2005-05-011-2/+14
| | | | | | | | | | | | For tree mount maps, a call to chdir or chroot, to a directory above the moint point directories at a certain time during the expire results in the expire incorrectly thinking the tree is not busy. This patch adds a check to see if the filesystem above the tree mount points is busy and also locks the filesystem during the tree mount expire to prevent the race. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds2005-04-161-0/+358
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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