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authorIan Kent <raven@themaw.net>2005-06-21 17:16:39 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-21 19:07:35 -0700
commitcc9acc885819696c0ed00f4f0f0cda0c7583f116 (patch)
tree118db1e835e0b69f3ed50926801990bd2b0d2b7d
parent9b1e3afd6d56937ced3914971621d0f053ea9178 (diff)
downloadlwn-cc9acc885819696c0ed00f4f0f0cda0c7583f116.tar.gz
lwn-cc9acc885819696c0ed00f4f0f0cda0c7583f116.zip
[PATCH] autofs4: post expire race fix
At the tail end of an expire it's possible for a process to enter autofs4_wait, with a waitq type of NFY_NONE but find that the expire is finished. In this cause autofs4_wait will try to create a new wait but not notify the daemon leading to a hang. As the wait type is meant to delay mount requests from revalidate or lookup during an expire and the expire is done all we need to do is check if the dentry is a mountpoint. If it's not then we're done. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--fs/autofs4/waitq.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
index 5a40d36e5a51..fa2348dcd671 100644
--- a/fs/autofs4/waitq.c
+++ b/fs/autofs4/waitq.c
@@ -191,6 +191,13 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
}
if ( !wq ) {
+ /* Can't wait for an expire if there's no mount */
+ if (notify == NFY_NONE && !d_mountpoint(dentry)) {
+ kfree(name);
+ up(&sbi->wq_sem);
+ return -ENOENT;
+ }
+
/* Create a new wait queue */
wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL);
if ( !wq ) {