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path: root/fs/namespace.c
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* [PATCH] VFS: Permit filesystem to override root dentry on mountDavid Howells2006-06-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] revert "vfs: propagate mnt_flags into do_loopback/vfsmount"Andrew Morton2006-05-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Revert commit f6422f17d3a480f21917a3895e2a46b968f56a08, due to Valdis.Kletnieks@vt.edu wrote: > > There seems to have been a bug introduced in this changeset: > > Am running 2.6.17-rc3-mm1. When this changeset is applied, 'mount --bind' > misbehaves: > > > # mkdir /foo > > # mount -t tmpfs -o rw,nosuid,nodev,noexec,noatime,nodiratime none /foo > > # mkdir /foo/bar > > # mount --bind /foo/bar /foo > > # tail -2 /proc/mounts > > none /foo tmpfs rw,nosuid,nodev,noexec,noatime,nodiratime 0 0 > > none /foo tmpfs rw 0 0 > > Reverting this changeset causes both mounts to have the same options. > > (Thanks to Stephen Smalley for tracking down the changeset...) > Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Christoph Hellwig <hch@infradead.org> Cc: <Valdis.Kletnieks@vt.edu> Cc: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] vfs: propagate mnt_flags into do_loopback/vfsmountHerbert Poetzl2006-04-11
| | | | | | | | | | The mnt_flags are propagated into do_loopback(), so that they can be stored with the vfsmount Signed-off-by: Herbert Poetzl <herbert@13thfloor.at> Acked-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] autofs4: change may_umount* functions to booleanIan Kent2006-03-27
| | | | | | | | | 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] Use __read_mostly on some hot fs variablesEric Dumazet2006-03-26
| | | | | | | | | | | | | | I discovered on oprofile hunting on a SMP platform that dentry lookups were slowed down because d_hash_mask, d_hash_shift and dentry_hashtable were in a cache line that contained inodes_stat. So each time inodes_stats is changed by a cpu, other cpus have to refill their cache line. This patch moves some variables to the __read_mostly section, in order to avoid false sharing. RCU dentry lookups can go full speed. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* VFS: New /proc file /proc/self/mountstatsChuck Lever2006-03-20
| | | | | | | | | | | | | | | | | Create a new file under /proc/self, called mountstats, where mounted file systems can export information (configuration options, performance counters, and so on). Use a mechanism similar to /proc/mounts and s_ops->show_options. This mechanism does not violate namespace security, and is safe to use while other processes are unmounting file systems. Thanks to Mike Waychison for his review and comments. Test-plan: Test concurrent mount/unmount operations while cat'ing /proc/self/mountstats. Signed-off-by: Chuck Lever <cel@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
* [PATCH] fs/namespace.c:dup_namespace(): fix a use after freeAdrian Bunk2006-03-15
| | | | | | | | | | | | | | | | | | | | | | The Coverity checker spotted the following bug in dup_namespace(): <-- snip --> if (!new_ns->root) { up_write(&namespace_sem); kfree(new_ns); goto out; } ... out: return new_ns; <-- snip --> Callers expect a non-NULL result to not be freed. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] umount_tree() decrements mount count on wrong dentryAl Viro2006-02-07
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [PATCH] unshare system call -v5: unshare namespaceJANAK DESAI2006-02-07
| | | | | | | | | | | | | | If the namespace structure is being shared, allocate a new one and copy information from the current, shared, structure. Signed-off-by: Janak Desai <janak@us.ibm.com> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] add /sys/fsMiklos Szeredi2006-01-17
| | | | | | | | | This patch adds an empty /sys/fs, which filesystems can use. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] capable/capability.h (fs/)Randy Dunlap2006-01-11
| | | | | | | | | fs: Use <linux/capability.h> where capable() is used. Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Acked-by: Tim Schmielau <tim@physik3.uni-rostock.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] per-mountpoint noatime/nodiratimeChristoph Hellwig2006-01-10
| | | | | | | | | | | | | | | | | | | | Turn noatime and nodiratime into per-mount instead of per-sb flags. After all the preparations this is a rather trivial patch. The mount code needs to treat the two options as per-mount instead of per-superblock, and touch_atime needs to be changed to check the new MNT_ flags in addition to the MS_ flags that are kept for filesystems that are always noatime/nodiratime but not user settable anymore. Besides that core code only nfs needed an update because it's leaving atime updates to the server and thus sets the S_NOATIME flag on every inode, but needs to know whether it's a real noatime mount for an getattr optimization. While we're at it I've killed the IS_NOATIME/IS_NODIRATIME macros that were only used by touch_atime. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_semJes Sorensen2006-01-09
| | | | | | | | | | | | | This patch converts the inode semaphore to a mutex. I have tested it on XFS and compiled as much as one can consider on an ia64. Anyway your luck with it might be different. Modified-by: Ingo Molnar <mingo@elte.hu> (finished the conversion) Signed-off-by: Jes Sorensen <jes@sgi.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* [PATCH] shared mounts: cleanupMiklos Szeredi2006-01-08
| | | | | | | | | | Small cleanups in shared mounts code. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: Ram Pai <linuxram@us.ibm.com> Cc: <viro@parcelfarce.linux.theplanet.co.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] pivot_root: add commentNeil Brown2006-01-08
| | | | | | Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] add a vfs_permission helperChristoph Hellwig2005-11-09
| | | | | | | | | | | Most permission() calls have a struct nameidata * available. This helper takes that as an argument and thus makes sure we pass it down for lookup intents and prepares for per-mount read-only support where we need a struct vfsmount for checking whether a file is writeable. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] unbindable mountsRam Pai2005-11-07
| | | | | | | | | | | | | | | | | | | | | An unbindable mount does not forward or receive propagation. Also unbindable mount disallows bind mounts. The semantics is as follows. Bind semantics: It is invalid to bind mount an unbindable mount. Move semantics: It is invalid to move an unbindable mount under shared mount. Clone-namespace semantics: If a mount is unbindable in the parent namespace, the corresponding cloned mount in the child namespace becomes unbindable too. Note: there is subtle difference, unbindable mounts cannot be bind mounted but can be cloned during clone-namespace. Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] handling of slave mountsRam Pai2005-11-07
| | | | | | | | | | This makes bind, rbind, move, clone namespace and umount operations aware of the semantics of slave mount (see Documentation/sharedsubtree.txt in the last patch of the series for detailed description). Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] introduce slave mountsRam Pai2005-11-07
| | | | | | | | | | A slave mount always has a master mount from which it receives mount/umount events. Unlike shared mount the event propagation does not flow from the slave mount to the master. Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] shared mounts handling: umountRam Pai2005-11-07
| | | | | | | | | | An unmount of a mount creates a umount event on the parent. If the parent is a shared mount, it gets propagated to all mounts in the peer group. Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] shared mounts handling: moveRam Pai2005-11-07
| | | | | | | | | | Implement handling of mount --move in presense of shared mounts (see Documentation/sharedsubtree.txt in the end of patch series for detailed description). Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] shared mount handling: bind and rbindRam Pai2005-11-07
| | | | | | | | | | Implement handling of MS_BIND in presense of shared mounts (see Documentation/sharedsubtree.txt in the end of patch series for detailed description). Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] introduce shared mountsRam Pai2005-11-07
| | | | | | | | | | | This creates shared mounts. A shared mount when bind-mounted to some mountpoint, propagates mount/umount events to each other. All the shared mounts that propagate events to each other belong to the same peer-group. Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] beginning of the shared-subtree properRam Pai2005-11-07
| | | | | | | | | A private mount does not forward or receive propagation. This patch provides user the ability to convert any mount to private. Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] making namespace_sem globalRam Pai2005-11-07
| | | | | | | | | | This removes the per-namespace semaphore in favor of a global semaphore. This can have an effect on namespace scalability. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mount expiry fixesRam Pai2005-11-07
| | | | | | | | | | | | - clean up the ugliness in may_umount_tree() - fix a bug in do_loopback(). after cloning a tree, do_loopback() unlinks only the topmost mount of the cloned tree, leaving behind the children mounts on their corresponding expiry list. Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] umount_tree() locking changeRam Pai2005-11-07
| | | | | | | | | | | | | | | | umount is done under the protection of the namespace semaphore. This can lead to intresting deadlocks when the last reference to a mount is released, if filesystem code is in sufficiently nasty state. This collects all the to-be-released-mounts and releases them after releasing the namespace semaphore. That both reduces the time we are holding namespace semaphore and gets the things more robust. Idea proposed by Al Viro. Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sanitize the interface of graft_tree().Ram Pai2005-11-07
| | | | | | | | | | | | | | | | Old semantics: graft_tree() grabs a reference on the vfsmount before returning success. New one: graft_tree() leaves that to caller. All the callers of graft_tree() immediately dropped that reference anyway. Changing the interface takes care of this unnecessary overhead. Idea proposed by Al Viro. Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] lindent fs/namespace.cRam Pai2005-11-07
| | | | | | Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] make /proc/mounts pollableAl Viro2005-11-07
| | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] cleanups and bug fix in do_loopback()Al Viro2005-11-07
| | | | | | | | | | | | | | - check_mnt() on the source of binding should've been unconditional from the very beginning. My fault - as far I could've trace it, that's an old thinko made back in 2001. Kudos to Miklos for spotting it... Fixed. - code cleaned up. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] saner handling of auto_acct_off() and DQUOT_OFF() in umountAl Viro2005-11-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The way we currently deal with quota and process accounting that might keep vfsmount busy at umount time is inherently broken; we try to turn them off just in case (not quite correctly, at that) and a) pray umount doesn't fail (otherwise they'll stay turned off) b) pray nobody doesn anything funny just as we turn quota off Moreover, LSM provides hooks for doing the same sort of broken logics. The proper way to deal with that is to introduce the second kind of reference to vfsmount. Semantics: - when the last normal reference is dropped, all special ones are converted to normal ones and if there had been any, cleanup is done. - normal reference can be cloned into a special one - special reference can be converted to normal one; that's a no-op if we'd already passed the point of no return (i.e. mntput() had converted special references to normal and started cleanup). The way it works: e.g. starting process accounting converts the vfsmount reference pinned by the opened file into special one and turns it back to normal when it gets shut down; acct_auto_close() is done when no normal references are left. That way it does *not* obstruct umount(2) and it silently gets turned off when the last normal reference to vfsmount is gone. Which is exactly what we want... The same should be done by LSM module that holds some internal references to vfsmount and wants to shut them down on umount - it should make them special and security_sb_umount_close() will be called exactly when the last normal reference to vfsmount is gone. quota handling is even simpler - we don't use normal file IO anymore, so there's no need to hold vfsmounts at all. DQUOT_OFF() is done from deactivate_super(), where it really belongs. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] janitor: fs/namespace.c: list_for_each_entryDomen Puncer2005-09-10
| | | | | | | | | Make code more readable with list_for_each_entry. Signed-off-by: Maximilian Attems <janitor@sternwelten.at> Signed-off-by: Domen Puncer <domen@coderock.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] pivot_root() circular reference fixMiklos Szeredi2005-09-07
| | | | | | | | | | | | | | | | | | | | | Fix http://bugzilla.kernel.org/show_bug.cgi?id=4857 When pivot_root is called from an init script in an initramfs environment, it causes a circular reference in the mount tree. The cause of this is that pivot_root() is not prepared to handle pivoting an unattached mount. In an initramfs environment, rootfs is the root of the namespace, and so it is not attached. This patch fixes this and related problems, by returning -EINVAL if either the current root or the new root is detached. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Acked-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk> Cc: <bigfish@asmallpond.org> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Additions to .data.read_mostly sectionRavikiran G Thirumalai2005-09-07
| | | | | | | | | | Mark variables which are usually accessed for reads with __readmostly. Signed-off-by: Alok N Kataria <alokk@calsoftinc.com> Signed-off-by: Shai Fultheim <shai@scalex86.org> Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] namespace.c: fix bind mount from foreign namespaceMiklos Szeredi2005-08-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I'm resending this patch, because I still believe it's the correct fix. Tested before/after applying the patch with a test application available from: http://www.inf.bme.hu/~mszeredi/nstest.c Bind mount from a foreign namespace results in an un-removable mount. The reason is that mnt->mnt_namespace is copied from the old mount in clone_mnt(). Because of this check_mnt() in sys_umount() will fail. The solution is to set mnt->mnt_namespace to current->namespace in clone_mnt(). clone_mnt() is either called from do_loopback() or copy_tree(). copy_tree() is called from do_loopback() or copy_namespace(). When called (directly or indirectly) from do_loopback(), always current->namspace is being modified: check_mnt(nd->mnt). So setting mnt->mnt_namespace to current->namspace is the right thing to do. When called from copy_namespace(), the setting of mnt_namespace is irrelevant, since mnt_namespace is reset later in that function for all copied mounts. Jamie said: This patch is correct. The old code was buggy for more fundamental and serious reason: it broke the invariant that a tree of vfsmnts all have the same value of mnt_namespace (and the same for the mnt_list list). Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Acked-by: Jamie Lokier <jamie@shareable.org> Cc: <viro@parcelfarce.linux.theplanet.co.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] namespace: rename mnt_fslink to mnt_expireMiklos Szeredi2005-07-07
| | | | | | | | | | | This patch renames vfsmount->mnt_fslink to something a little more descriptive: vfsmount->mnt_expire. Signed-off-by: Mike Waychison <michael.waychison@sun.com> Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] set mnt_namespace in the correct placeMiklos Szeredi2005-07-07
| | | | | | | | | | | | | | | | | This patch sets ->mnt_namespace where it's actually added to the namespace. Previously mnt_namespace was set in do_kern_mount() even if the filesystem was never added to any process's namespace (most kernel-internal filesystems). This discrepancy doesn't actually cause any problems, but it's cleaner if mnt_namespace is NULL for these non exported filesystems. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] namespace.c: fix mnt_namespace zeroing for expired mountsMiklos Szeredi2005-07-07
| | | | | | | | | | | | | | | This patch clears mnt_namespace in an expired mount. If mnt_namespace is not cleared, it's possible to attach a new mount to the already detached mount, because check_mnt() can return true. The effect is a resource leak, since the resulting tree will never be freed. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] namespace.c: fix expiring of detached mountMiklos Szeredi2005-07-07
| | | | | | | | | | | | | | | | | | This patch fixes a bug noticed by Al Viro: However, we still have a problem here - just what would happen if vfsmount is detached while we were grabbing namespace semaphore? Refcount alone is not useful here - we might be held by whoever had detached the vfsmount. IOW, we should check that it's still attached (i.e. that mnt->mnt_parent != mnt). If it's not - just leave it alone, do mntput() and let whoever holds it deal with the sucker. No need to put it back on lists. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: <viro@parcelfarce.linux.theplanet.co.uk> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] namespace.c: split mark_mounts_for_expiry()Miklos Szeredi2005-07-07
| | | | | | | | | | | | | This patch splits the mark_mounts_for_expiry() function. It's too complex and too deeply nested, even without the bugfix in the following patch. Otherwise code is completely the same. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: <viro@parcelfarce.linux.theplanet.co.uk> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] namespace.c: cleanup in mark_mounts_for_expiry()Miklos Szeredi2005-07-07
| | | | | | | | | | | | | | | | This patch simplifies mark_mounts_for_expiry() by using detach_mnt() instead of duplicating everything it does. It should be an equivalent transformation except for righting the dput/mntput order. Al Viro said: "Looks sane". Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: <viro@parcelfarce.linux.theplanet.co.uk> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] namespace.c: fix race in mark_mounts_for_expiry()Miklos Szeredi2005-07-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes a race found by Ram in mark_mounts_for_expiry() in fs/namespace.c. The bug can only be triggered with simultaneous exiting of a process having a private namespace, and expiry of a mount from within that namespace. It's practically impossible to trigger, and I haven't even tried. But still, a bug is a bug. The race happens when put_namespace() is called by another task, while mark_mounts_for_expiry() is between atomic_read() and get_namespace(). In that case get_namespace() will be called on an already dead namespace with unforeseeable results. The solution was suggested by Al Viro, with his own words: Instead of screwing with atomic_read() in there, why don't we simply do the following: a) atomic_dec_and_lock() in put_namespace() b) __put_namespace() called without dropping lock c) the first thing done by __put_namespace would be struct vfsmount *root = namespace->root; namespace->root = NULL; spin_unlock(...); .... umount_tree(root); ... d) check in mark_... would be simply namespace && namespace->root. And we are all set; no screwing around with atomic_read(), no magic at all. Dying namespace gets NULL ->root. All changes of ->root happen under spinlock. If under a spinlock we see non-NULL ->mnt_namespace, it won't be freed until we drop the lock (we will set ->mnt_namespace to NULL under that lock before we get to freeing namespace). If under a spinlock we see non-NULL ->mnt_namespace and ->mnt_namespace->root, we can grab a reference to namespace and be sure that it won't go away. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Acked-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] namespace.c: fix mnt_namespace clearingMiklos Szeredi2005-07-07
| | | | | | | | | | | | | | | | | | | | | | | | This patch clears mnt_namespace on unmount. Not clearing mnt_namespace has two effects: 1) It is possible to attach a new mount to a detached mount, because check_mnt() returns true. This means, that when no other references to the detached mount remain, it still can't be freed. This causes a resource leak, and possibly un-removable modules. 2) If mnt_namespace is dereferenced (only in mark_mounts_for_expiry()) after the namspace has been freed, it can cause an Oops, memory corruption, etc. 1) has been tested before and after the patch, 2) is only speculation. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] make various thing staticAdrian Bunk2005-06-24
| | | | | | | | Another rollup of patches which give various symbols static scope Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds2005-04-16
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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