user/sven/linux.git/include/linux/namei.h, branch v4.1.15

make nameidata completely opaque outside of fs/namei.c

2014-12-11T02:32:13Z

Signed-off-by: Al Viro

RCU'd vfsmounts

2013-11-09T05:16:19Z

* RCU-delayed freeing of vfsmounts * vfsmount_lock replaced with a seqlock (mount_lock) * sequence number from mount_lock is stored in nameidata->m_seq and used when we exit RCU mode * new vfsmount flag - MNT_SYNC_UMOUNT. Set by umount_tree() when its caller knows that vfsmount will have no surviving references. * synchronize_rcu() done between unlocking namespace_sem in namespace_unlock() and doing pending mntput(). * new helper: legitimize_mnt(mnt, seq). Checks the mount_lock sequence number against seq, then grabs reference to mnt. Then it rechecks mount_lock again to close the race and either returns success or drops the reference it has acquired. The subtle point is that in case of MNT_SYNC_UMOUNT we can simply decrement the refcount and sod off - aforementioned synchronize_rcu() makes sure that final mntput() won't come until we leave RCU mode. We need that, since we don't want to end up with some lazy pathwalk racing with umount() and stealing the final mntput() from it - caller of umount() may expect it to return only once the fs is shut down and we don't want to break that. In other cases (i.e. with MNT_SYNC_UMOUNT absent) we have to do full-blown mntput() in case of mount_lock sequence number mismatch happening just as we'd grabbed the reference, but in those cases we won't be stealing the final mntput() from anything that would care. * mntput_no_expire() doesn't lock anything on the fast path now. Incidentally, SMP and UP cases are handled the same way - no ifdefs there. * normal pathname resolution does *not* do any writes to mount_lock. It does, of course, bump the refcounts of vfsmount and dentry in the very end, but that's it. Signed-off-by: Al Viro

introduce kern_path_mountpoint()

2013-09-09T00:20:23Z

Signed-off-by: Al Viro

rename user_path_umountat() to user_path_mountpoint_at()

2013-09-09T00:20:21Z

... and move the extern from linux/namei.h to fs/internal.h, along with that of vfs_path_lookup(). Signed-off-by: Al Viro

vfs: allow umount to handle mountpoints without revalidating them

2013-09-04T02:50:29Z

Christopher reported a regression where he was unable to unmount a NFS filesystem where the root had gone stale. The problem is that d_revalidate handles the root of the filesystem differently from other dentries, but d_weak_revalidate does not. We could simply fix this by making d_weak_revalidate return success on IS_ROOT dentries, but there are cases where we do want to revalidate the root of the fs. A umount is really a special case. We generally aren't interested in anything but the dentry and vfsmount that's attached at that point. If the inode turns out to be stale we just don't care since the intent is to stop using it anyway. Try to handle this situation better by treating umount as a special case in the lookup code. Have it resolve the parent using normal means, and then do a lookup of the final dentry without revalidating it. In most cases, the final lookup will come out of the dcache, but the case where there's a trailing symlink or !LAST_NORM entry on the end complicates things a bit. Cc: Neil Brown Reported-by: Christopher T Vogan Signed-off-by: Jeff Layton Signed-off-by: Al Viro

namei.h: include errno.h

2012-12-25T23:45:06Z

This solves: In file included from fs/ext3/symlink.c:20:0: include/linux/namei.h: In function 'retry_estale': include/linux/namei.h:114:19: error: 'ESTALE' undeclared (first use in this function) Signed-off-by: Stephen Warren Signed-off-by: Al Viro

vfs: turn is_dir argument to kern_path_create into a lookup_flags arg

2012-12-20T23:50:02Z

Where we can pass in LOOKUP_DIRECTORY or LOOKUP_REVAL. Any other flags passed in here are currently ignored. Signed-off-by: Jeff Layton Signed-off-by: Al Viro

vfs: add a retry_estale helper function to handle retries on ESTALE

2012-12-20T23:50:00Z

This function is expected to be called from path-based syscalls to help them decide whether to try the lookup and call again in the event that they got an -ESTALE return back on an earier try. Currently, we only retry the call once on an ESTALE error, but in the event that we decide that that's not enough in the future, we should be able to change the logic in this helper without too much effort. Signed-off-by: Jeff Layton Signed-off-by: Al Viro

new helper: done_path_create()

2012-07-29T17:24:13Z

releases what needs to be released after {kern,user}_path_create() Signed-off-by: Al Viro

fs: add nd_jump_link

2012-07-14T12:35:40Z

Add a helper that abstracts out the jump to an already parsed struct path from ->follow_link operation from procfs. Not only does this clean up the code by moving the two sides of this game into a single helper, but it also prepares for making struct nameidata private to namei.c Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro