From: Ian Kent <ikent@redhat.com> Date: Tue, 12 Aug 2008 12:28:29 +0800 Subject: [autofs4] fix pending checks Message-id: 20080812042827.15842.32103.stgit@web.messagingengine.com O-Subject: [RHEL 5.3 PATCH 16/20] autofs4 - fix pending checks [bz452139] Bugzilla: 452139 This patch contributes to the resolution of bugs 458749, 448936 and 452139. There are two cases for which a dentry that has a pending mount request does not wait for completion. One is via autofs4_revalidate() and the other via autofs4_follow_link(). In revalidate, after the mount point directory is created, but before the mount is done, the check in try_to_fill_dentry() can can fail to send the dentry to the wait queue since the dentry is positive and the lookup flags may contain only LOOKUP_FOLLOW. Although we don't trigger a mount for the LOOKUP_FOLLOW flag, if ther's one pending we might as well wait and use the mounted dentry for the lookup. In autofs4_follow_link() the dentry is not checked to see if it is pending so it may fail to call try_to_fill_dentry() and not wait for mount completion. A dentry that is pending must always be sent to the wait queue. Signed-off-by: Ian Kent <raven@themaw.net> diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c index 2bcbd1b..6920daf 100644 --- a/fs/autofs4/root.c +++ b/fs/autofs4/root.c @@ -178,7 +178,8 @@ static int try_to_fill_dentry(struct dentry *dentry, int flags) return status; } /* Trigger mount for path component or follow link */ - } else if (flags & (TRIGGER_FLAGS | TRIGGER_INTENTS) || + } else if (dentry->d_flags & DCACHE_AUTOFS_PENDING || + flags & (TRIGGER_FLAGS | TRIGGER_INTENTS) || current->link_count) { DPRINTK("waiting for mount name=%.*s", dentry->d_name.len, dentry->d_name.name); @@ -223,7 +224,8 @@ static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd) /* If it's our master or we shouldn't trigger a mount we're done */ lookup_type = nd->flags & (TRIGGER_FLAGS | TRIGGER_INTENTS); - if (oz_mode || !lookup_type) + if (oz_mode || + !(lookup_type || dentry->d_flags & DCACHE_AUTOFS_PENDING)) goto done; /* If an expire request is pending wait for it. */ @@ -242,7 +244,8 @@ static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd) * don't try to mount it again. */ spin_lock(&dcache_lock); - if (!d_mountpoint(dentry) && __simple_empty(dentry)) { + if (dentry->d_flags & DCACHE_AUTOFS_PENDING || + (!d_mountpoint(dentry) && __simple_empty(dentry))) { spin_unlock(&dcache_lock); status = try_to_fill_dentry(dentry, 0);