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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@themaw.net>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ian Kent 2008-07-23 21:30:28 -07:00 committed by Linus Torvalds
parent ec6e8c7d3f
commit 06a3598552
3 changed files with 40 additions and 65 deletions
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1
fs/autofs4/autofs_i.h
View File

@ -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 *);

29
fs/autofs4/expire.c
View File

@ -402,6 +402,35 @@ static struct dentry *autofs4_expire_indirect(struct super_block *sb,
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,

75
fs/autofs4/root.c
View File

@ -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);
@ -248,22 +220,8 @@ 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);
autofs4_expire_wait(dentry);
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);
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))
@ -331,6 +289,14 @@ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
if (oz_mode)
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.
@ -339,15 +305,6 @@ 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);
@ -557,19 +514,7 @@ 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);