The patch titled
Subject: autofs: don't hold spinlock over direct mount expire
has been added to the -mm tree. Its filename is
autofs-dont-hold-spin-lock-over-direct-mount-expire.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/autofs-dont-hold-spin-lock-over-direct-mount-expire.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/autofs-dont-hold-spin-lock-over-direct-mount-expire.patch
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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Ian Kent <ikent@xxxxxxxxxx>
Subject: autofs: don't hold spinlock over direct mount expire
Commit 7cbdb4a286 ("autofs: use dentry flags to block walks during
expire") altered the autofs indirect mount expire to not hold a spin lock
during the expire check.
The direct mount expire needs the same treatment because to
make autofs expires namespace aware may_umount_tree() needs to
to use a similar method to may_umount() when checking if a mount
tree is in use.
This means may_umount_tree() will end up taking the namespace_sem
for the check so the autofs direct mount expire won't be allowed
to hold a spin lock over the check.
Link: http://lkml.kernel.org/r/148029913453.27779.15747032937407838983.stgit@xxxxxxxxxxxxxxxx
Signed-off-by: Ian Kent <raven@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Omar Sandoval <osandov@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/autofs4/expire.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff -puN fs/autofs4/expire.c~autofs-dont-hold-spin-lock-over-direct-mount-expire fs/autofs4/expire.c
--- a/fs/autofs4/expire.c~autofs-dont-hold-spin-lock-over-direct-mount-expire
+++ a/fs/autofs4/expire.c
@@ -310,26 +310,29 @@ struct dentry *autofs4_expire_direct(str
now = jiffies;
timeout = sbi->exp_timeout;
- spin_lock(&sbi->fs_lock);
- ino = autofs4_dentry_ino(root);
- /* No point expiring a pending mount */
- if (ino->flags & AUTOFS_INF_PENDING)
- goto out;
if (!autofs4_direct_busy(mnt, root, timeout, do_now)) {
+ spin_lock(&sbi->fs_lock);
+ ino = autofs4_dentry_ino(root);
+ /* No point expiring a pending mount */
+ if (ino->flags & AUTOFS_INF_PENDING) {
+ spin_unlock(&sbi->fs_lock);
+ goto out;
+ }
ino->flags |= AUTOFS_INF_WANT_EXPIRE;
spin_unlock(&sbi->fs_lock);
synchronize_rcu();
- spin_lock(&sbi->fs_lock);
if (!autofs4_direct_busy(mnt, root, timeout, do_now)) {
+ spin_lock(&sbi->fs_lock);
ino->flags |= AUTOFS_INF_EXPIRING;
init_completion(&ino->expire_complete);
spin_unlock(&sbi->fs_lock);
return root;
}
+ spin_lock(&sbi->fs_lock);
ino->flags &= ~AUTOFS_INF_WANT_EXPIRE;
+ spin_unlock(&sbi->fs_lock);
}
out:
- spin_unlock(&sbi->fs_lock);
dput(root);
return NULL;
_
Patches currently in -mm which might be from ikent@xxxxxxxxxx are
vfs-change-d_manage-to-take-a-struct-path.patch
vfs-add-path_is_mountpoint-helper.patch
vfs-add-path_has_submounts.patch
autofs-change-autofs4_expire_wait-to-take-struct-path.patch
autofs-change-autofs4_wait-to-take-struct-path.patch
autofs-use-path_is_mountpoint-to-fix-unreliable-d_mountpoint-checks.patch
autofs-use-path_has_submounts-to-fix-unreliable-have_submount-checks.patch
vfs-remove-unused-have_submounts-function.patch
vfs-merge-path_is_mountpoint-and-path_is_mountpoint_rcu.patch
autofs-make-struct-path-const-in-autofs4_dir_open.patch
autofs-change-struct-path-to-const-in-autofs4_expire_wait-and-autofs4_wait.patch
vfs-change-struct-path-to-const-in-d_manage.patch
vfs-constify-path-parameter-of-path_has_submounts.patch
autofs-dont-hold-spin-lock-over-direct-mount-expire.patch
vfs-make-may_umount_tree-mount-propogation-aware.patch
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