Messages in this thread Patch in this message | | | Date | Sat, 4 Jun 2005 15:40:43 +0800 (WST) | From | raven@themaw ... | Subject | [PATCH] autofs4 - post expire race fix |
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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.
diff -Nur linux-2.6.12-rc2-mm3.orig/fs/autofs4/waitq.c linux-2.6.12-rc2-mm3/fs/autofs4/waitq.c --- linux-2.6.12-rc2-mm3.orig/fs/autofs4/waitq.c 2005-05-01 17:04:49.000000000 +0800 +++ linux-2.6.12-rc2-mm3/fs/autofs4/waitq.c 2005-05-01 17:07:18.000000000 +0800 @@ -191,6 +191,13 @@ } 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 ) { - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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