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Message-ID: <20080718023737.12802.24898.stgit@raven.themaw.net>
Date: Fri, 18 Jul 2008 10:37:44 +0800
From: Ian Kent <raven@...maw.net>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: autofs mailing list <autofs@...ux.kernel.org>,
Kernel Mailing List <linux-kernel@...r.kernel.org>,
linux-fsdevel <linux-fsdevel@...r.kernel.org>,
Al Viro <viro@...IV.linux.org.uk>,
Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH 6/7] autofs4 - reorganize expire pending wait function calls
This patch re-orgnirzes the checking for and waiting on
active expires and elininates redundant checks.
Signed-off-by: Ian Kent <raven@...maw.net>
---
fs/autofs4/autofs_i.h | 1 +
fs/autofs4/expire.c | 29 +++++++++++++++++++
fs/autofs4/root.c | 75 +++++++------------------------------------------
3 files changed, 40 insertions(+), 65 deletions(-)
diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index 4b40cbc..69a2f5c 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -163,6 +163,7 @@ void autofs4_free_ino(struct autofs_info *);
/* Expiration */
int is_autofs4_dentry(struct dentry *);
+int autofs4_expire_wait(struct dentry *dentry);
int autofs4_expire_run(struct super_block *, struct vfsmount *,
struct autofs_sb_info *,
struct autofs_packet_expire __user *);
diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index 705b9f0..cdabb79 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -402,6 +402,35 @@ found:
return expired;
}
+int autofs4_expire_wait(struct dentry *dentry)
+{
+ struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+ struct autofs_info *ino = autofs4_dentry_ino(dentry);
+ int status;
+
+ /* Block on any pending expire */
+ spin_lock(&sbi->fs_lock);
+ if (ino->flags & AUTOFS_INF_EXPIRING) {
+ spin_unlock(&sbi->fs_lock);
+
+ DPRINTK("waiting for expire %p name=%.*s",
+ dentry, dentry->d_name.len, dentry->d_name.name);
+
+ status = autofs4_wait(sbi, dentry, NFY_NONE);
+ wait_for_completion(&ino->expire_complete);
+
+ DPRINTK("expire done status=%d", status);
+
+ if (d_unhashed(dentry))
+ return -EAGAIN;
+
+ return status;
+ }
+ spin_unlock(&sbi->fs_lock);
+
+ return 0;
+}
+
/* Perform an expiry operation */
int autofs4_expire_run(struct super_block *sb,
struct vfsmount *mnt,
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index bdf190b..9c39fa7 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -130,34 +130,6 @@ static int try_to_fill_dentry(struct dentry *dentry, int flags)
struct autofs_info *ino = autofs4_dentry_ino(dentry);
int status;
- /* Block on any pending expiry here; invalidate the dentry
- when expiration is done to trigger mount request with a new
- dentry */
- spin_lock(&sbi->fs_lock);
- if (ino->flags & AUTOFS_INF_EXPIRING) {
- spin_unlock(&sbi->fs_lock);
-
- DPRINTK("waiting for expire %p name=%.*s",
- dentry, dentry->d_name.len, dentry->d_name.name);
-
- status = autofs4_wait(sbi, dentry, NFY_NONE);
- wait_for_completion(&ino->expire_complete);
-
- DPRINTK("expire done status=%d", status);
-
- /*
- * If the directory still exists the mount request must
- * continue otherwise it can't be followed at the right
- * time during the walk.
- */
- status = d_invalidate(dentry);
- if (status != -EBUSY)
- return -EAGAIN;
-
- goto cont;
- }
- spin_unlock(&sbi->fs_lock);
-cont:
DPRINTK("dentry=%p %.*s ino=%p",
dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
@@ -254,22 +226,8 @@ static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd)
}
/* If an expire request is pending everyone must wait. */
- spin_lock(&sbi->fs_lock);
- if (ino->flags & AUTOFS_INF_EXPIRING) {
- spin_unlock(&sbi->fs_lock);
-
- DPRINTK("waiting for active request %p name=%.*s",
- dentry, dentry->d_name.len, dentry->d_name.name);
-
- status = autofs4_wait(sbi, dentry, NFY_NONE);
- wait_for_completion(&ino->expire_complete);
+ autofs4_expire_wait(dentry);
- DPRINTK("request done status=%d", status);
-
- goto cont;
- }
- spin_unlock(&sbi->fs_lock);
-cont:
/* We trigger a mount for almost all flags */
lookup_type = nd->flags & (TRIGGER_FLAGS | TRIGGER_INTENTS);
if (!(lookup_type || dentry->d_flags & DCACHE_AUTOFS_PENDING))
@@ -338,6 +296,14 @@ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
return 1;
/*
+ * If the directory has gone away due to an expire
+ * we have been called as ->d_revalidate() and so
+ * we need to return false and proceed to ->lookup().
+ */
+ if (autofs4_expire_wait(dentry) == -EAGAIN)
+ return 0;
+
+ /*
* A zero status is success otherwise we have a
* negative error code.
*/
@@ -345,15 +311,6 @@ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
if (status == 0)
return 1;
- /*
- * A status of EAGAIN here means that the dentry has gone
- * away while waiting for an expire to complete. If we are
- * racing with expire lookup will wait for it so this must
- * be a revalidate and we need to send it to lookup.
- */
- if (status == -EAGAIN)
- return 0;
-
return status;
}
spin_unlock(&sbi->fs_lock);
@@ -563,19 +520,7 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s
* so it must have been successful, so just wait for it.
*/
ino = autofs4_dentry_ino(expiring);
- spin_lock(&sbi->fs_lock);
- if (ino->flags & AUTOFS_INF_EXPIRING) {
- spin_unlock(&sbi->fs_lock);
- DPRINTK("wait for incomplete expire %p name=%.*s",
- expiring, expiring->d_name.len,
- expiring->d_name.name);
- autofs4_wait(sbi, expiring, NFY_NONE);
- wait_for_completion(&ino->expire_complete);
- DPRINTK("request completed");
- goto cont;
- }
- spin_unlock(&sbi->fs_lock);
-cont:
+ autofs4_expire_wait(expiring);
spin_lock(&sbi->lookup_lock);
if (!list_empty(&ino->expiring))
list_del_init(&ino->expiring);
--
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