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Diffstat (limited to 'kernel/fs/autofs4')
-rw-r--r--kernel/fs/autofs4/autofs_i.h8
-rw-r--r--kernel/fs/autofs4/expire.c80
-rw-r--r--kernel/fs/autofs4/root.c2
3 files changed, 56 insertions, 34 deletions
diff --git a/kernel/fs/autofs4/autofs_i.h b/kernel/fs/autofs4/autofs_i.h
index 4c5413473..05af8d3e6 100644
--- a/kernel/fs/autofs4/autofs_i.h
+++ b/kernel/fs/autofs4/autofs_i.h
@@ -80,9 +80,13 @@ struct autofs_info {
};
#define AUTOFS_INF_EXPIRING (1<<0) /* dentry is in the process of expiring */
-#define AUTOFS_INF_NO_RCU (1<<1) /* the dentry is being considered
+#define AUTOFS_INF_WANT_EXPIRE (1<<1) /* the dentry is being considered
* for expiry, so RCU_walk is
- * not permitted
+ * not permitted. If it progresses to
+ * actual expiry attempt, the flag is
+ * not cleared when EXPIRING is set -
+ * in that case it gets cleared only
+ * when it comes to clearing EXPIRING.
*/
#define AUTOFS_INF_PENDING (1<<2) /* dentry pending mount */
diff --git a/kernel/fs/autofs4/expire.c b/kernel/fs/autofs4/expire.c
index d487fa27a..d08bcdc30 100644
--- a/kernel/fs/autofs4/expire.c
+++ b/kernel/fs/autofs4/expire.c
@@ -315,19 +315,17 @@ struct dentry *autofs4_expire_direct(struct super_block *sb,
if (ino->flags & AUTOFS_INF_PENDING)
goto out;
if (!autofs4_direct_busy(mnt, root, timeout, do_now)) {
- ino->flags |= AUTOFS_INF_NO_RCU;
+ ino->flags |= AUTOFS_INF_WANT_EXPIRE;
spin_unlock(&sbi->fs_lock);
synchronize_rcu();
spin_lock(&sbi->fs_lock);
if (!autofs4_direct_busy(mnt, root, timeout, do_now)) {
ino->flags |= AUTOFS_INF_EXPIRING;
- smp_mb();
- ino->flags &= ~AUTOFS_INF_NO_RCU;
init_completion(&ino->expire_complete);
spin_unlock(&sbi->fs_lock);
return root;
}
- ino->flags &= ~AUTOFS_INF_NO_RCU;
+ ino->flags &= ~AUTOFS_INF_WANT_EXPIRE;
}
out:
spin_unlock(&sbi->fs_lock);
@@ -417,6 +415,7 @@ static struct dentry *should_expire(struct dentry *dentry,
}
return NULL;
}
+
/*
* Find an eligible tree to time-out
* A tree is eligible if :-
@@ -432,6 +431,7 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
struct dentry *root = sb->s_root;
struct dentry *dentry;
struct dentry *expired;
+ struct dentry *found;
struct autofs_info *ino;
if (!root)
@@ -442,48 +442,54 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
dentry = NULL;
while ((dentry = get_next_positive_subdir(dentry, root))) {
+ int flags = how;
+
spin_lock(&sbi->fs_lock);
ino = autofs4_dentry_ino(dentry);
- if (ino->flags & AUTOFS_INF_NO_RCU)
- expired = NULL;
- else
- expired = should_expire(dentry, mnt, timeout, how);
- if (!expired) {
+ if (ino->flags & AUTOFS_INF_WANT_EXPIRE) {
spin_unlock(&sbi->fs_lock);
continue;
}
+ spin_unlock(&sbi->fs_lock);
+
+ expired = should_expire(dentry, mnt, timeout, flags);
+ if (!expired)
+ continue;
+
+ spin_lock(&sbi->fs_lock);
ino = autofs4_dentry_ino(expired);
- ino->flags |= AUTOFS_INF_NO_RCU;
+ ino->flags |= AUTOFS_INF_WANT_EXPIRE;
spin_unlock(&sbi->fs_lock);
synchronize_rcu();
- spin_lock(&sbi->fs_lock);
- if (should_expire(expired, mnt, timeout, how)) {
- if (expired != dentry)
- dput(dentry);
- goto found;
- }
- ino->flags &= ~AUTOFS_INF_NO_RCU;
+ /* Make sure a reference is not taken on found if
+ * things have changed.
+ */
+ flags &= ~AUTOFS_EXP_LEAVES;
+ found = should_expire(expired, mnt, timeout, how);
+ if (!found || found != expired)
+ /* Something has changed, continue */
+ goto next;
+
if (expired != dentry)
- dput(expired);
+ dput(dentry);
+
+ spin_lock(&sbi->fs_lock);
+ goto found;
+next:
+ spin_lock(&sbi->fs_lock);
+ ino->flags &= ~AUTOFS_INF_WANT_EXPIRE;
spin_unlock(&sbi->fs_lock);
+ if (expired != dentry)
+ dput(expired);
}
return NULL;
found:
DPRINTK("returning %p %pd", expired, expired);
ino->flags |= AUTOFS_INF_EXPIRING;
- smp_mb();
- ino->flags &= ~AUTOFS_INF_NO_RCU;
init_completion(&ino->expire_complete);
spin_unlock(&sbi->fs_lock);
- spin_lock(&sbi->lookup_lock);
- spin_lock(&expired->d_parent->d_lock);
- spin_lock_nested(&expired->d_lock, DENTRY_D_LOCK_NESTED);
- list_move(&expired->d_parent->d_subdirs, &expired->d_child);
- spin_unlock(&expired->d_lock);
- spin_unlock(&expired->d_parent->d_lock);
- spin_unlock(&sbi->lookup_lock);
return expired;
}
@@ -492,15 +498,27 @@ int autofs4_expire_wait(struct dentry *dentry, int rcu_walk)
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
int status;
+ int state;
/* Block on any pending expire */
- if (!(ino->flags & (AUTOFS_INF_EXPIRING | AUTOFS_INF_NO_RCU)))
+ if (!(ino->flags & AUTOFS_INF_WANT_EXPIRE))
return 0;
if (rcu_walk)
return -ECHILD;
+retry:
spin_lock(&sbi->fs_lock);
- if (ino->flags & AUTOFS_INF_EXPIRING) {
+ state = ino->flags & (AUTOFS_INF_WANT_EXPIRE | AUTOFS_INF_EXPIRING);
+ if (state == AUTOFS_INF_WANT_EXPIRE) {
+ spin_unlock(&sbi->fs_lock);
+ /*
+ * Possibly being selected for expire, wait until
+ * it's selected or not.
+ */
+ schedule_timeout_uninterruptible(HZ/10);
+ goto retry;
+ }
+ if (state & AUTOFS_INF_EXPIRING) {
spin_unlock(&sbi->fs_lock);
DPRINTK("waiting for expire %p name=%pd", dentry, dentry);
@@ -551,7 +569,7 @@ int autofs4_expire_run(struct super_block *sb,
ino = autofs4_dentry_ino(dentry);
/* avoid rapid-fire expire attempts if expiry fails */
ino->last_used = now;
- ino->flags &= ~AUTOFS_INF_EXPIRING;
+ ino->flags &= ~(AUTOFS_INF_EXPIRING|AUTOFS_INF_WANT_EXPIRE);
complete_all(&ino->expire_complete);
spin_unlock(&sbi->fs_lock);
@@ -579,7 +597,7 @@ int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
spin_lock(&sbi->fs_lock);
/* avoid rapid-fire expire attempts if expiry fails */
ino->last_used = now;
- ino->flags &= ~AUTOFS_INF_EXPIRING;
+ ino->flags &= ~(AUTOFS_INF_EXPIRING|AUTOFS_INF_WANT_EXPIRE);
complete_all(&ino->expire_complete);
spin_unlock(&sbi->fs_lock);
dput(dentry);
diff --git a/kernel/fs/autofs4/root.c b/kernel/fs/autofs4/root.c
index c6d7d3dbd..7a54c6a86 100644
--- a/kernel/fs/autofs4/root.c
+++ b/kernel/fs/autofs4/root.c
@@ -455,7 +455,7 @@ static int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
* a mount-trap.
*/
struct inode *inode;
- if (ino->flags & (AUTOFS_INF_EXPIRING | AUTOFS_INF_NO_RCU))
+ if (ino->flags & AUTOFS_INF_WANT_EXPIRE)
return 0;
if (d_mountpoint(dentry))
return 0;