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path: root/fs/autofs4/root.c
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* switch follow_down()Al Viro2009-06-111-4/+3
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: fix lookup deadlockIan Kent2009-04-011-20/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A deadlock can occur when user space uses a signal (autofs version 4 uses SIGCHLD for this) to effect expire completion. The order of events is: Expire process completes, but before being able to send SIGCHLD to it's parent ... Another process walks onto a different mount point and drops the directory inode semaphore prior to sending the request to the daemon as it must ... A third process does an lstat on on the expired mount point causing it to wait on expire completion (unfortunately) holding the directory semaphore. The mount request then arrives at the daemon which does an lstat and, deadlock. For some time I was concerned about releasing the directory semaphore around the expire wait in autofs4_lookup as well as for the mount call back. I finally realized that the last round of changes in this function made the expiring dentry and the lookup dentry separate and distinct so the check and possible wait can be done anywhere prior to the mount call back. This patch moves the check to just before the mount call back and inside the directory inode mutex release. 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>
* constify dentry_operations: autofs, autofs4Al Viro2009-03-271-2/+2
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [PATCH] fix ->llseek() for a bunch of directoriesAl Viro2008-08-251-0/+2
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: remove unused ioctlsIan Kent2008-07-241-67/+1
| | | | | | | | | | | The ioctls AUTOFS_IOC_TOGGLEREGHOST and AUTOFS_IOC_ASKREGHOST were added several years ago but what they were intended for has never been implemented (as far as I'm aware noone uses them) so remove them. 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>
* autofs4: reorganize expire pending wait function callsIan Kent2008-07-241-65/+10
| | | | | | | | | | 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 race - correctionIan Kent2008-07-241-8/+2
| | | | | | | | | | Appologies, somehow I seem to have sent an out dated version of this patch. Here is an additional patch that brings the patch up to date. 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 Kent2008-07-241-23/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 Kent2008-07-241-5/+27
| | | | | | | | | | | | | | | | | 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>
* autofs4: fix pending checksIan Kent2008-07-241-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | There are two cases for which a dentry that has a pending mount request does not wait for completion. One is via autofs4_revalidate() and the other via autofs4_follow_link(). In revalidate, after the mount point directory is created, but before the mount is done, the check in try_to_fill_dentry() can can fail to send the dentry to the wait queue since the dentry is positive and the lookup flags may contain only LOOKUP_FOLLOW. Although we don't trigger a mount for the LOOKUP_FOLLOW flag, if ther's one pending we might as well wait and use the mounted dentry for the lookup. In autofs4_follow_link() the dentry is not checked to see if it is pending so it may fail to call try_to_fill_dentry() and not wait for mount completion. A dentry that is pending must always be sent to the wait queue. 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>
* autofs4: cleanup redundant readir codeIan Kent2008-07-241-133/+16
| | | | | | | | | | | The mount triggering functionality of readdir and related functions is no longer used (and is quite broken as well). The unused portions have been removed. 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>
* autofs4: use lookup intent flags to trigger mountsIan Kent2008-07-241-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When an open(2) call is made on an autofs mount point directory that already exists and the O_DIRECTORY flag is not used the needed mount callback to the daemon is not done. This leads to the path walk continuing resulting in a callback to the daemon with an incorrect key. open(2) is called without O_DIRECTORY by the "find" utility but this should be handled properly anyway. This happens because autofs needs to use the lookup flags to decide when to callback to the daemon to perform a mount to prevent mount storms. For example, an autofs indirect mount map that has the "browse" option will have the mount point directories are pre-created and the stat(2) call made by a color ls against each directory will cause all these directories to be mounted. It is unfortunate we need to resort to this but mount maps can be quite large. Additionally, if a user manually umounts an autofs indirect mount the directory isn't removed which also leads to this situation. To resolve this autofs needs to use the lookup intent flags to enable it to make this decision. This patch adds this check and triggers a call back if any of the lookup intent flags are set as all these calls warrant a mount attempt be requested. I know that external VFS code which uses the lookup flags is something that the VFS would like to eliminate but I have no choice as I can't see any other way to do this. A VFS dentry or inode operation callback which returns the lookup "type" (requires a definition) would be sufficient. But this change is needed now and I'm not aware of the form that coming VFS changes will take so I'm not willing to propose anything along these lines. If anyone can provide an alternate method I would be happy to use it. [akpm@linux-foundation.org: fix build for concurrent VFS changes] Signed-off-by: Ian Kent <raven@themaw.net> Cc: Al Viro <viro@zeniv.linux.org.uk> 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: don't release directory mutex if called in oz_modeIan Kent2008-07-241-6/+5
| | | | | | | | | | | | | | | | | | | Since we now delay hashing of dentrys until the ->mkdir() call, droping and re-taking the directory mutex within the ->lookup() function when we are being called by user space is not needed. This can lead to a race when other processes are attempting to access the same directory during mount point directory creation. In this case we need to hang onto the mutex to ensure we don't get user processes trying to create a mount request for a newly created dentry after the mount point entry has already been created. This ensures that when we need to check a dentry passed to autofs4_wait(), if it is hashed, it is always the mount point dentry and not a new dentry created by another lookup during directory creation. 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: fix symlink name allocationIan Kent2008-07-241-1/+1
| | | | | | | | | | The length of the symlink name has been moved but it needs to be set before allocating space for it in the dentry info struct. This corrects a mistake in a recent patch. 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: use look aside list for lookupsIan Kent2008-07-241-30/+139
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A while ago a patch to resolve a deadlock during directory creation was merged. This delayed the hashing of lookup dentrys until the ->mkdir() (or ->symlink()) operation completed to ensure we always went through ->lookup() instead of also having processes go through ->revalidate() so our VFS locking remained consistent. Now we are seeing a couple of side affects of that change in situations with heavy mount activity. Two cases have been identified: 1) When a mount request is triggered, due to the delayed hashing, the directory created by user space for the mount point doesn't have the DCACHE_AUTOFS_PENDING flag set. In the case of an autofs multi-mount where a tree of mount point directories are created this can lead to the path walk continuing rather than the dentry being sent to the wait queue to wait for request completion. This is because, if the pending flag isn't set, the criteria for deciding this is a mount in progress fails to hold, namely that the dentry is not a mount point and has no subdirectories. 2) A mount request dentry is initially created negative and unhashed. It remains this way until the ->mkdir() callback completes. Since it is unhashed a fresh dentry is used when the user space mount request creates the mount point directory. This leaves the original dentry negative and unhashed. But revalidate has no way to tell the VFS that the dentry has changed, other than to force another ->lookup() by returning false, which is at best wastefull and at worst not possible. This results in an -ENOENT return from the original path walk when in fact the mount succeeded. To resolve this we need to ensure that the same dentry is used in all calls to ->lookup() during the course of a mount request. This patch achieves that by adding the initial dentry to a look aside list and removes it at ->mkdir() or ->symlink() completion (or when the dentry is released), since these are the only create operations autofs4 supports. 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: revert - redo lookup in ttfdIan Kent2008-07-241-21/+0
| | | | | | | | | | | This patch series enables the use of a single dentry for lookups prior to the dentry being hashed and so we no longer need to redo the lookup. This patch reverts the patch of commit 033790449ba9c4dcf8478a87693d33df625c23b5. 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: don't make expiring dentry negativeIan Kent2008-07-241-72/+46
| | | | | | | | | | | | | | | | | | | Correct the error of making a positive dentry negative after it has been instantiated. The code that makes this error attempts to re-use the dentry from a concurrent expire and mount to resolve a race and the dentry used for the lookup must be negative for mounts to trigger in the required cases. The fact is that the dentry doesn't need to be re-used because all that is needed is to preserve the flag that indicates an expire is still incomplete at the time of the mount request. This change uses the the dentry to check the flag and wait for the expire to complete then discards it instead of attempting to re-use it. 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>
* autofs: path_{get,put}() cleanupsJan Blunck2008-05-011-6/+6
| | | | | | | | | | | 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 incorrect return from root.c:try_to_fill_dentry()Jeff Moyer2008-05-011-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Jeff Moyer has identified a case where the autofs4 function root.c:try_to_fill_dentry() can return -EBUSY when it should return 0. Jeff's description of the way this happens is: "automount starts an expire for directory d. after the callout to the daemon, but before the rmdir, another process tries to walk into the same directory. It puts itself onto the waitq, pending the expiration. When the expire finishes, the second process is woken up. In try_to_fill_dentry, it does this check: status = d_invalidate(dentry); if (status != -EBUSY) return -EAGAIN; And status is EBUSY. The dentry still has a non-zero d_inode, and the flags do not contain LOOKUP_CONTINUE or LOOKUP_DIRECTORY So, we fall through and return -EBUSY to the caller." Signed-off-by: Jeff Moyer <jmoyer@redhat.com> 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: fix execution order race in mount request codeJeff Moyer2008-05-011-0/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Jeff Moyer has identified a race in due to an execution order dependency in the autofs4 function root.c:try_to_fill_dentry(). Jeff's description of this race is: "P1 does a lookup of /mount/submount/foo. Since the VFS can't find an entry for "foo" under /mount/submount, it calls into the autofs4 kernel module to allocate a new dentry, D1. The kernel creates a new waitq for this lookup and calls the daemon to perform the mount. The daemon performs a mkdir of the "foo" directory under /mount/submount, which ends up creating a *new* dentry, D2. Then, P2 does a lookup of /mount/submount/foo. The VFS path walking logic finds a dentry in the dcache, D2, and calls the revalidate function with this. In the autofs4 revalidate code, we then trigger a mount, since the dentry is an empty directory that isn't a mountpoint, and so set DCACHE_AUTOFS_PENDING and call into the wait code to trigger the mount. The wait code finds our existing waitq entry (since it is keyed off of the directory name) and adds itself to the list of waiters. After the daemon finishes the mount, it calls back into the kernel to release the waiters. When this happens, P1 is woken up and goes about clearing the DCACHE_AUTOFS_PENDING flag, but it does this in D1! So, given that P1 in our case is a program that will immediately try to access a file under /mount/submount/foo, we end up finding the dentry D2 which still has the pending flag set, and we set out to wait for a mount *again*! So, one way to address this is to re-do the lookup at the end of try_to_fill_dentry, and to clear the pending flag on the hashed dentry. This seems a sane approach to me." And Jeff's patch does this. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by-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: fix sparse warning in root.cHarvey Harrison2008-04-291-1/+1
| | | | | | | | | | | | | fs/autofs4/root.c:536:23: warning: symbol 'ino' shadows an earlier one fs/autofs4/root.c:510:22: originally declared here There is no need to redeclare, we are at the end of the loop and in the next iteration of the loop, ino will be reset. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Introduce path_put()Jan Blunck2008-02-141-1/+1
| | | | | | | | | | | | | | | | | | | * Add path_put() functions for releasing a reference to the dentry and vfsmount of a struct path in the right order * Switch from path_release(nd) to path_put(&nd->path) * Rename dput_path() to path_put_conditional() [akpm@linux-foundation.org: fix cifs] Signed-off-by: Jan Blunck <jblunck@suse.de> Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Acked-by: Christoph Hellwig <hch@lst.de> Cc: <linux-fsdevel@vger.kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Steven French <sfrench@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Embed a struct path into struct nameidata instead of nd->{dentry,mnt}Jan Blunck2008-02-141-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is the central patch of a cleanup series. In most cases there is no good reason why someone would want to use a dentry for itself. This series reflects that fact and embeds a struct path into nameidata. Together with the other patches of this series - it enforced the correct order of getting/releasing the reference count on <dentry,vfsmount> pairs - it prepares the VFS for stacking support since it is essential to have a struct path in every place where the stack can be traversed - it reduces the overall code size: without patch series: text data bss dec hex filename 5321639 858418 715768 6895825 6938d1 vmlinux with patch series: text data bss dec hex filename 5320026 858418 715768 6894212 693284 vmlinux This patch: Switch from nd->{dentry,mnt} to nd->path.{dentry,mnt} everywhere. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix cifs] [akpm@linux-foundation.org: fix smack] Signed-off-by: Jan Blunck <jblunck@suse.de> Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Acked-by: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pid namespaces: round up the APIPavel Emelianov2007-10-191-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | The set of functions process_session, task_session, process_group and task_pgrp is confusing, as the names can be mixed with each other when looking at the code for a long time. The proposals are to * equip the functions that return the integer with _nr suffix to represent that fact, * and to make all functions work with task (not process) by making the common prefix of the same name. For monotony the routines signal_session() and set_signal_session() are replaced with task_session_nr() and set_task_session(), especially since they are only used with the explicit task->signal dereference. Signed-off-by: Pavel Emelianov <xemul@openvz.org> Acked-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: deadlock during createIan Kent2007-08-221-14/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | Due to inconsistent locking in the VFS between calls to lookup and revalidate deadlock can occur in the automounter. The inconsistency is that the directory inode mutex is held for both lookup and revalidate calls when called via lookup_hash whereas it is held only for lookup during a path walk. Consequently, if the mutex is held during a call to revalidate autofs4 can't release the mutex to callback the daemon as it can't know whether it owns the mutex. This situation happens when a process tries to create a directory within an automount and a second process also tries to create the same directory between the lookup and the mkdir. Since the first process has dropped the mutex for the daemon callback, the second process takes it during revalidate leading to deadlock between the autofs daemon and the second process when the daemon tries to create the mount point directory. After spending quite a bit of time trying to resolve this on more than one occassion, using rather complex and ulgy approaches, it turns out that just delaying the hashing of the dentry until the create operation works fine. 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>
* Fix some coding-style errors in autofsSukadev Bhattiprolu2007-05-111-9/+9
| | | | | | | | | | | | | | | Fix coding style errors (extra spaces, long lines) in autofs and autofs4 files being modified for container/pidspace issues. Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: <containers@lists.osdl.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* header cleaning: don't include smp_lock.h when not usedRandy Dunlap2007-05-081-1/+0
| | | | | | | | | | | | Remove includes of <linux/smp_lock.h> where it is not used/needed. Suggested by Al Viro. Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc, sparc64, and arm (all 59 defconfigs). Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] autofs4: fix race in unhashed dentry codeJeff Mahoney2007-04-121-3/+3
| | | | | | | | | | | | | | | | | | | | Commit f50b6f8691cae2e0064c499dd3ef3f31142987f0 introduced a race in autofs4 between autofs_lookup_unhashed() and autofs_dentry_release(). autofs_dentry_release() ends up clearing the ->dentry and ->inode members of autofs_info before removing it from the rehash list. The list is protected by the rehash lock in both functions, but since autofs_dentry_release() starts tearing the autofs_info struct down before removing it from the list, autofs_lookup_unhashed() can get a autofs_info with a NULL dentry. This patch moves the clearing of ->dentry and ->inode after the removal from the rehash list. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] autofs4: check for directory re-create in lookupIan Kent2007-02-201-4/+19
| | | | | | | | | | | | | | | | This problem was identified and fixed some time ago by Jeff Moyer but it fell through the cracks somehow. It is possible that a user space application could remove and re-create a directory during a request. To avoid returning a failure from lookup incorrectly when our current dentry is unhashed we need to check if another positive, hashed dentry matching this one exists and if so return it instead of a fail. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> 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>
* [PATCH] autofs4: fix another race between mount and expireIan Kent2007-02-201-20/+151
| | | | | | | | | | | | | | | | | | | | | | Jeff Moyer has identified a race between mount and expire. What happens is that during an expire the situation can arise that a directory is removed and another lookup is done before the expire issues a completion status to the kernel module. In this case, since the the lookup gets a new dentry, it doesn't know that there is an expire in progress and when it posts its mount request, matches the existing expire request and waits for its completion. ENOENT is then returned to user space from lookup (as the dentry passed in is now unhashed) without having performed the mount request. The solution used here is to keep track of dentrys in this unhashed state and reuse them, if possible, in order to preserve the flags. Additionally, this infrastructure will provide the framework for the reintroduction of caching of mount fails removed earlier in development. Signed-off-by: Ian Kent <raven@themaw.net> Acked-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] mark struct inode_operations const 1Arjan van de Ven2007-02-121-3/+3
| | | | | | | | | | | Many struct inode_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] autofs4: change uses of f_{dentry, vfsmnt} to use f_pathJosef "Jeff" Sipek2006-12-081-8/+8
| | | | | | | | | Change all the uses of f_{dentry,vfsmnt} to f_path.{dentry,mnt} in the autofs4 filesystem. Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] r/o bind mounts: monitor zeroing of i_nlinkDave Hansen2006-10-011-2/+2
| | | | | | | | | | | | Some filesystems, instead of simply decrementing i_nlink, simply zero it during an unlink operation. We need to catch these in addition to the decrement operations. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Acked-by: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] r/o bind mount prepwork: inc_nlink() helperDave Hansen2006-10-011-1/+1
| | | | | | | | | | | This is mostly included for parity with dec_nlink(), where we will have some more hooks. This one should stay pretty darn straightforward for now. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Acked-by: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] r/o bind mounts: unlink: monitor i_nlinkDave Hansen2006-10-011-1/+1
| | | | | | | | | | | | | | | | | When a filesystem decrements i_nlink to zero, it means that a write must be performed in order to drop the inode from the filesystem. We're shortly going to have keep filesystems from being remounted r/o between the time that this i_nlink decrement and that write occurs. So, add a little helper function to do the decrements. We'll tie into it in a bit to note when i_nlink hits zero. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Acked-by: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs4: pending flag not cleared on mount failIan Kent2006-09-291-3/+3
| | | | | | | | | | During testing I've found that the mount pending flag can be left set at exit from autofs4_lookup after a failed mount request. This shouldn't be allowed to happen and causes incorrect error returns. 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: autofs4_follow_link false negative fixIan Kent2006-09-291-1/+1
| | | | | | | | | | | The check for an empty directory in the autofs4_follow_link method fails occassionally due to old dentrys. We had the same problem autofs4_revalidate ages ago. I thought we wouldn't need this in autofs4_follow_link, silly me. 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 needs to force fail return revalidateIan Kent2006-09-271-8/+30
| | | | | | | | | | | | | | | | | | | | | | For a long time now I have had a problem with not being able to return a lookup failure on an existsing directory. In autofs this corresponds to a mount failure on a autofs managed mount entry that is browsable (and so the mount point directory exists). While this problem has been present for a long time I've avoided resolving it because it was not very visible. But now that autofs v5 has "mount and expire on demand" of nested multiple mounts, such as is found when mounting an export list from a server, solving the problem cannot be avoided any longer. I've tried very hard to find a way to do this entirely within the autofs4 module but have not been able to find a satisfactory way to achieve it. So, I need to propose a change to the VFS. 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: NFY_NONE wait race fixIan Kent2006-05-151-7/+3
| | | | | | | | | | | | | | | | | | | | This patch fixes two problems. First, the comparison of entries in the waitq.c was incorrect. Second, the NFY_NONE check was incorrect. The test of whether the dentry is mounted if ineffective, for example, if an expire fails then we could wait forever on a non existant expire. The bug was identified by Jeff Moyer. The patch changes autofs4 to wait on expires only as this is all that's needed. If there is no existing wait when autofs4_wait is call with a type of NFY_NONE it delays until either a wait appears or the the expire flag is cleared. 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] Make most file operations structs in fs/ constArjan van de Ven2006-03-281-2/+2
| | | | | | | | | | | | | | This is a conversion to make the various file_operations structs in fs/ const. Basically a regexp job, with a few manual fixups The goal is both to increase correctness (harder to accidentally write to shared datastructures) and reducing the false sharing of cachelines with things that get dirty in .data (while .rodata is nicely read only and thus cache clean) Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs4: follow_link missing functionalityIan Kent2006-03-271-6/+44
| | | | | | | | 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: add v5 follow_link mount trigger methodIan Kent2006-03-271-12/+52
| | | | | | | | | | | | This patch adds a follow_link inode method for the root of an autofs direct mount trigger. It also adds the corresponding mount options and updates the show_mount method. 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: rename simple_empty_nolock functionIan Kent2006-03-271-1/+1
| | | | | | | | | Rename the function simple_empty_nolock to __simple_empty in line with kernel naming conventions. 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: remove update_atime unused functionIan Kent2006-03-271-34/+4
| | | | | | | | | Remove the update of i_atime from autofs4 in favour of having VFS update it. i_atime is never used for expire in autofs4. 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 Kent2006-03-271-0/+4
| | | | | | | | | | | | | | | | | | | | | | 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 Kent2006-03-271-1/+22
| | | | | | | | | | | | | | | 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: can't mount due to mount point dir not emptyIan Kent2006-03-271-5/+4
| | | | | | | | | | | | | | | | | | | | Addresse a problem where stale dentrys stop mounts from happening. When a mount point directory is pre-created and a non-existent entry within it is requested a dentry ends up being created within the mount point directory which stops future mounts. The problem is solved by ignoring negative, unhashed dentrys in the mount point d_subdirs list. Additionally the apparent cacheing of -ENOENT returns from requests is removed. The test on d_time is a tautology and d_time is not initialised and has an unexpected value. In short it doesn't do what it's meant to. The cacheing of failed requests to the daemon is important and will be followed up later. 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: use libfs routines for readdirIan Kent2006-03-271-86/+40
| | | | | | | | | | Change readdir routines to use the cursor based routines in libfs.c. This removes reliance on old readdir code from 2.4 and should improve efficiency of readdir in autofs4. 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: lookup white space cleanupIan Kent2006-03-271-14/+20
| | | | | | | | Whitespace and formating changes to lookup code. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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