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path: root/fs/autofs4/expire.c
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Diffstat (limited to 'fs/autofs4/expire.c')
-rw-r--r--fs/autofs4/expire.c141
1 files changed, 77 insertions, 64 deletions
diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index a796c9417fb1..cc1d01365905 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -91,24 +91,64 @@ done:
}
/*
- * Calculate next entry in top down tree traversal.
- * From next_mnt in namespace.c - elegant.
+ * Calculate and dget next entry in top down tree traversal.
*/
-static struct dentry *next_dentry(struct dentry *p, struct dentry *root)
+static struct dentry *get_next_positive_dentry(struct dentry *prev,
+ struct dentry *root)
{
- struct list_head *next = p->d_subdirs.next;
+ struct list_head *next;
+ struct dentry *p, *ret;
+
+ if (prev == NULL)
+ return dget(prev);
+ spin_lock(&autofs4_lock);
+relock:
+ p = prev;
+ spin_lock(&p->d_lock);
+again:
+ next = p->d_subdirs.next;
if (next == &p->d_subdirs) {
while (1) {
- if (p == root)
+ struct dentry *parent;
+
+ if (p == root) {
+ spin_unlock(&p->d_lock);
+ spin_unlock(&autofs4_lock);
+ dput(prev);
return NULL;
+ }
+
+ parent = p->d_parent;
+ if (!spin_trylock(&parent->d_lock)) {
+ spin_unlock(&p->d_lock);
+ cpu_relax();
+ goto relock;
+ }
+ spin_unlock(&p->d_lock);
next = p->d_u.d_child.next;
- if (next != &p->d_parent->d_subdirs)
+ p = parent;
+ if (next != &parent->d_subdirs)
break;
- p = p->d_parent;
}
}
- return list_entry(next, struct dentry, d_u.d_child);
+ ret = list_entry(next, struct dentry, d_u.d_child);
+
+ spin_lock_nested(&ret->d_lock, DENTRY_D_LOCK_NESTED);
+ /* Negative dentry - try next */
+ if (!simple_positive(ret)) {
+ spin_unlock(&ret->d_lock);
+ p = ret;
+ goto again;
+ }
+ dget_dlock(ret);
+ spin_unlock(&ret->d_lock);
+ spin_unlock(&p->d_lock);
+ spin_unlock(&autofs4_lock);
+
+ dput(prev);
+
+ return ret;
}
/*
@@ -158,18 +198,11 @@ static int autofs4_tree_busy(struct vfsmount *mnt,
if (!simple_positive(top))
return 1;
- spin_lock(&dcache_lock);
- for (p = top; p; p = next_dentry(p, top)) {
- /* Negative dentry - give up */
- if (!simple_positive(p))
- continue;
-
+ p = NULL;
+ while ((p = get_next_positive_dentry(p, top))) {
DPRINTK("dentry %p %.*s",
p, (int) p->d_name.len, p->d_name.name);
- p = dget(p);
- spin_unlock(&dcache_lock);
-
/*
* Is someone visiting anywhere in the subtree ?
* If there's no mount we need to check the usage
@@ -198,16 +231,13 @@ static int autofs4_tree_busy(struct vfsmount *mnt,
else
ino_count++;
- if (atomic_read(&p->d_count) > ino_count) {
+ if (p->d_count > ino_count) {
top_ino->last_used = jiffies;
dput(p);
return 1;
}
}
- dput(p);
- spin_lock(&dcache_lock);
}
- spin_unlock(&dcache_lock);
/* Timeout of a tree mount is ultimately determined by its top dentry */
if (!autofs4_can_expire(top, timeout, do_now))
@@ -226,32 +256,21 @@ static struct dentry *autofs4_check_leaves(struct vfsmount *mnt,
DPRINTK("parent %p %.*s",
parent, (int)parent->d_name.len, parent->d_name.name);
- spin_lock(&dcache_lock);
- for (p = parent; p; p = next_dentry(p, parent)) {
- /* Negative dentry - give up */
- if (!simple_positive(p))
- continue;
-
+ p = NULL;
+ while ((p = get_next_positive_dentry(p, parent))) {
DPRINTK("dentry %p %.*s",
p, (int) p->d_name.len, p->d_name.name);
- p = dget(p);
- spin_unlock(&dcache_lock);
-
if (d_mountpoint(p)) {
/* Can we umount this guy */
if (autofs4_mount_busy(mnt, p))
- goto cont;
+ continue;
/* Can we expire this guy */
if (autofs4_can_expire(p, timeout, do_now))
return p;
}
-cont:
- dput(p);
- spin_lock(&dcache_lock);
}
- spin_unlock(&dcache_lock);
return NULL;
}
@@ -276,7 +295,9 @@ struct dentry *autofs4_expire_direct(struct super_block *sb,
struct autofs_info *ino = autofs4_dentry_ino(root);
if (d_mountpoint(root)) {
ino->flags |= AUTOFS_INF_MOUNTPOINT;
- root->d_mounted--;
+ spin_lock(&root->d_lock);
+ root->d_flags &= ~DCACHE_MOUNTED;
+ spin_unlock(&root->d_lock);
}
ino->flags |= AUTOFS_INF_EXPIRING;
init_completion(&ino->expire_complete);
@@ -302,8 +323,8 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
{
unsigned long timeout;
struct dentry *root = sb->s_root;
+ struct dentry *dentry;
struct dentry *expired = NULL;
- struct list_head *next;
int do_now = how & AUTOFS_EXP_IMMEDIATE;
int exp_leaves = how & AUTOFS_EXP_LEAVES;
struct autofs_info *ino;
@@ -315,23 +336,8 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
now = jiffies;
timeout = sbi->exp_timeout;
- spin_lock(&dcache_lock);
- next = root->d_subdirs.next;
-
- /* On exit from the loop expire is set to a dgot dentry
- * to expire or it's NULL */
- while ( next != &root->d_subdirs ) {
- struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
-
- /* Negative dentry - give up */
- if (!simple_positive(dentry)) {
- next = next->next;
- continue;
- }
-
- dentry = dget(dentry);
- spin_unlock(&dcache_lock);
-
+ dentry = NULL;
+ while ((dentry = get_next_positive_dentry(dentry, root))) {
spin_lock(&sbi->fs_lock);
ino = autofs4_dentry_ino(dentry);
@@ -347,7 +353,7 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
/* Path walk currently on this dentry? */
ino_count = atomic_read(&ino->count) + 2;
- if (atomic_read(&dentry->d_count) > ino_count)
+ if (dentry->d_count > ino_count)
goto next;
/* Can we umount this guy */
@@ -369,7 +375,7 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
if (!exp_leaves) {
/* Path walk currently on this dentry? */
ino_count = atomic_read(&ino->count) + 1;
- if (atomic_read(&dentry->d_count) > ino_count)
+ if (dentry->d_count > ino_count)
goto next;
if (!autofs4_tree_busy(mnt, dentry, timeout, do_now)) {
@@ -383,7 +389,7 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
} else {
/* Path walk currently on this dentry? */
ino_count = atomic_read(&ino->count) + 1;
- if (atomic_read(&dentry->d_count) > ino_count)
+ if (dentry->d_count > ino_count)
goto next;
expired = autofs4_check_leaves(mnt, dentry, timeout, do_now);
@@ -394,11 +400,7 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
}
next:
spin_unlock(&sbi->fs_lock);
- dput(dentry);
- spin_lock(&dcache_lock);
- next = next->next;
}
- spin_unlock(&dcache_lock);
return NULL;
found:
@@ -408,9 +410,13 @@ found:
ino->flags |= AUTOFS_INF_EXPIRING;
init_completion(&ino->expire_complete);
spin_unlock(&sbi->fs_lock);
- spin_lock(&dcache_lock);
+ spin_lock(&autofs4_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_u.d_child);
- spin_unlock(&dcache_lock);
+ spin_unlock(&expired->d_lock);
+ spin_unlock(&expired->d_parent->d_lock);
+ spin_unlock(&autofs4_lock);
return expired;
}
@@ -499,7 +505,14 @@ int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
spin_lock(&sbi->fs_lock);
if (ino->flags & AUTOFS_INF_MOUNTPOINT) {
- sb->s_root->d_mounted++;
+ spin_lock(&sb->s_root->d_lock);
+ /*
+ * If we haven't been expired away, then reset
+ * mounted status.
+ */
+ if (mnt->mnt_parent != mnt)
+ sb->s_root->d_flags |= DCACHE_MOUNTED;
+ spin_unlock(&sb->s_root->d_lock);
ino->flags &= ~AUTOFS_INF_MOUNTPOINT;
}
ino->flags &= ~AUTOFS_INF_EXPIRING;