*
* Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
* Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
- * Copyright 2001-2003 Ian Kent <raven@themaw.net>
+ * Copyright 2001-2006 Ian Kent <raven@themaw.net>
*
* This file is part of the Linux kernel and is made available under
* the terms of the GNU General Public License, version 2, or at your
static unsigned long now;
-/* Check if a dentry can be expired return 1 if it can else return 0 */
+/* Check if a dentry can be expired */
static inline int autofs4_can_expire(struct dentry *dentry,
unsigned long timeout, int do_now)
{
attempts if expire fails the first time */
ino->last_used = now;
}
-
return 1;
}
-/* Check a mount point for busyness return 1 if not busy, otherwise */
-static int autofs4_check_mount(struct vfsmount *mnt, struct dentry *dentry)
+/* Check a mount point for busyness */
+static int autofs4_mount_busy(struct vfsmount *mnt, struct dentry *dentry)
{
- int status = 0;
+ struct dentry *top = dentry;
+ int status = 1;
DPRINTK("dentry %p %.*s",
dentry, (int)dentry->d_name.len, dentry->d_name.name);
mntget(mnt);
dget(dentry);
- if (!follow_down(&mnt, &dentry))
+ if (!autofs4_follow_mount(&mnt, &dentry))
goto done;
- while (d_mountpoint(dentry) && follow_down(&mnt, &dentry))
- ;
-
/* This is an autofs submount, we can't expire it */
if (is_autofs4_dentry(dentry))
goto done;
- /* The big question */
- if (may_umount_tree(mnt) == 0)
- status = 1;
+ /* Update the expiry counter if fs is busy */
+ if (!may_umount_tree(mnt)) {
+ struct autofs_info *ino = autofs4_dentry_ino(top);
+ ino->last_used = jiffies;
+ goto done;
+ }
+
+ status = 0;
done:
DPRINTK("returning = %d", status);
mntput(mnt);
return status;
}
+/*
+ * Calculate next entry in top down tree traversal.
+ * From next_mnt in namespace.c - elegant.
+ */
+static struct dentry *next_dentry(struct dentry *p, struct dentry *root)
+{
+ struct list_head *next = p->d_subdirs.next;
+
+ if (next == &p->d_subdirs) {
+ while (1) {
+ if (p == root)
+ return NULL;
+ next = p->d_u.d_child.next;
+ if (next != &p->d_parent->d_subdirs)
+ break;
+ p = p->d_parent;
+ }
+ }
+ return list_entry(next, struct dentry, d_u.d_child);
+}
+
+/*
+ * Check a direct mount point for busyness.
+ * Direct mounts have similar expiry semantics to tree mounts.
+ * The tree is not busy iff no mountpoints are busy and there are no
+ * autofs submounts.
+ */
+static int autofs4_direct_busy(struct vfsmount *mnt,
+ struct dentry *top,
+ unsigned long timeout,
+ int do_now)
+{
+ DPRINTK("top %p %.*s",
+ top, (int) top->d_name.len, top->d_name.name);
+
+ /* If it's busy update the expiry counters */
+ if (!may_umount_tree(mnt)) {
+ struct autofs_info *ino = autofs4_dentry_ino(top);
+ if (ino)
+ ino->last_used = jiffies;
+ return 1;
+ }
+
+ /* Timeout of a direct mount is determined by its top dentry */
+ if (!autofs4_can_expire(top, timeout, do_now))
+ return 1;
+
+ return 0;
+}
+
/* Check a directory tree of mount points for busyness
* The tree is not busy iff no mountpoints are busy
- * Return 1 if the tree is busy or 0 otherwise
*/
-static int autofs4_check_tree(struct vfsmount *mnt,
- struct dentry *top,
- unsigned long timeout,
- int do_now)
+static int autofs4_tree_busy(struct vfsmount *mnt,
+ struct dentry *top,
+ unsigned long timeout,
+ int do_now)
{
- struct dentry *this_parent = top;
- struct list_head *next;
+ struct autofs_info *top_ino = autofs4_dentry_ino(top);
+ struct dentry *p;
- DPRINTK("parent %p %.*s",
+ DPRINTK("top %p %.*s",
top, (int)top->d_name.len, top->d_name.name);
/* Negative dentry - give up */
if (!simple_positive(top))
- return 0;
-
- /* Timeout of a tree mount is determined by its top dentry */
- if (!autofs4_can_expire(top, timeout, do_now))
- return 0;
-
- /* Is someone visiting anywhere in the tree ? */
- if (may_umount_tree(mnt))
- return 0;
+ return 1;
spin_lock(&dcache_lock);
-repeat:
- next = this_parent->d_subdirs.next;
-resume:
- while (next != &this_parent->d_subdirs) {
- struct dentry *dentry = list_entry(next, struct dentry, d_child);
-
+ for (p = top; p; p = next_dentry(p, top)) {
/* Negative dentry - give up */
- if (!simple_positive(dentry)) {
- next = next->next;
+ if (!simple_positive(p))
continue;
- }
DPRINTK("dentry %p %.*s",
- dentry, (int)dentry->d_name.len, dentry->d_name.name);
-
- if (!simple_empty_nolock(dentry)) {
- this_parent = dentry;
- goto repeat;
- }
+ p, (int) p->d_name.len, p->d_name.name);
- dentry = dget(dentry);
+ p = dget(p);
spin_unlock(&dcache_lock);
- if (d_mountpoint(dentry)) {
- /* First busy => tree busy */
- if (!autofs4_check_mount(mnt, dentry)) {
- dput(dentry);
- return 0;
+ /*
+ * Is someone visiting anywhere in the subtree ?
+ * If there's no mount we need to check the usage
+ * count for the autofs dentry.
+ * If the fs is busy update the expiry counter.
+ */
+ if (d_mountpoint(p)) {
+ if (autofs4_mount_busy(mnt, p)) {
+ top_ino->last_used = jiffies;
+ dput(p);
+ return 1;
+ }
+ } else {
+ struct autofs_info *ino = autofs4_dentry_ino(p);
+ unsigned int ino_count = atomic_read(&ino->count);
+
+ /*
+ * Clean stale dentries below that have not been
+ * invalidated after a mount fail during lookup
+ */
+ d_invalidate(p);
+
+ /* allow for dget above and top is already dgot */
+ if (p == top)
+ ino_count += 2;
+ else
+ ino_count++;
+
+ if (atomic_read(&p->d_count) > ino_count) {
+ top_ino->last_used = jiffies;
+ dput(p);
+ return 1;
}
}
-
- dput(dentry);
+ dput(p);
spin_lock(&dcache_lock);
- next = next->next;
- }
-
- if (this_parent != top) {
- next = this_parent->d_child.next;
- this_parent = this_parent->d_parent;
- goto resume;
}
spin_unlock(&dcache_lock);
- return 1;
+ /* Timeout of a tree mount is ultimately determined by its top dentry */
+ if (!autofs4_can_expire(top, timeout, do_now))
+ return 1;
+
+ return 0;
}
static struct dentry *autofs4_check_leaves(struct vfsmount *mnt,
unsigned long timeout,
int do_now)
{
- struct dentry *this_parent = parent;
- struct list_head *next;
+ struct dentry *p;
DPRINTK("parent %p %.*s",
parent, (int)parent->d_name.len, parent->d_name.name);
spin_lock(&dcache_lock);
-repeat:
- next = this_parent->d_subdirs.next;
-resume:
- while (next != &this_parent->d_subdirs) {
- struct dentry *dentry = list_entry(next, struct dentry, d_child);
-
+ for (p = parent; p; p = next_dentry(p, parent)) {
/* Negative dentry - give up */
- if (!simple_positive(dentry)) {
- next = next->next;
+ if (!simple_positive(p))
continue;
- }
DPRINTK("dentry %p %.*s",
- dentry, (int)dentry->d_name.len, dentry->d_name.name);
-
- if (!list_empty(&dentry->d_subdirs)) {
- this_parent = dentry;
- goto repeat;
- }
+ p, (int) p->d_name.len, p->d_name.name);
- dentry = dget(dentry);
+ p = dget(p);
spin_unlock(&dcache_lock);
- if (d_mountpoint(dentry)) {
- /* Can we expire this guy */
- if (!autofs4_can_expire(dentry, timeout, do_now))
- goto cont;
-
+ if (d_mountpoint(p)) {
/* Can we umount this guy */
- if (autofs4_check_mount(mnt, dentry))
- return dentry;
+ if (autofs4_mount_busy(mnt, p))
+ goto cont;
+ /* Can we expire this guy */
+ if (autofs4_can_expire(p, timeout, do_now))
+ return p;
}
cont:
- dput(dentry);
+ dput(p);
spin_lock(&dcache_lock);
- next = next->next;
}
+ spin_unlock(&dcache_lock);
+ return NULL;
+}
+
+/* Check if we can expire a direct mount (possibly a tree) */
+static struct dentry *autofs4_expire_direct(struct super_block *sb,
+ struct vfsmount *mnt,
+ struct autofs_sb_info *sbi,
+ int how)
+{
+ unsigned long timeout;
+ struct dentry *root = dget(sb->s_root);
+ int do_now = how & AUTOFS_EXP_IMMEDIATE;
+
+ if (!sbi->exp_timeout || !root)
+ return NULL;
+
+ now = jiffies;
+ timeout = sbi->exp_timeout;
+
+ /* Lock the tree as we must expire as a whole */
+ spin_lock(&sbi->fs_lock);
+ if (!autofs4_direct_busy(mnt, root, timeout, do_now)) {
+ struct autofs_info *ino = autofs4_dentry_ino(root);
- if (this_parent != parent) {
- next = this_parent->d_child.next;
- this_parent = this_parent->d_parent;
- goto resume;
+ /* Set this flag early to catch sys_chdir and the like */
+ ino->flags |= AUTOFS_INF_EXPIRING;
+ spin_unlock(&sbi->fs_lock);
+ return root;
}
- spin_unlock(&dcache_lock);
+ spin_unlock(&sbi->fs_lock);
+ dput(root);
return NULL;
}
* - it is unused by any user process
* - it has been unused for exp_timeout time
*/
-static struct dentry *autofs4_expire(struct super_block *sb,
- struct vfsmount *mnt,
- struct autofs_sb_info *sbi,
- int how)
+static struct dentry *autofs4_expire_indirect(struct super_block *sb,
+ struct vfsmount *mnt,
+ struct autofs_sb_info *sbi,
+ int how)
{
unsigned long timeout;
struct dentry *root = sb->s_root;
/* 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_child);
+ struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
/* Negative dentry - give up */
- if ( !simple_positive(dentry) ) {
+ if (!simple_positive(dentry)) {
next = next->next;
continue;
}
dentry = dget(dentry);
spin_unlock(&dcache_lock);
- /* Case 1: indirect mount or top level direct mount */
+ /*
+ * Case 1: (i) indirect mount or top level pseudo direct mount
+ * (autofs-4.1).
+ * (ii) indirect mount with offset mount, check the "/"
+ * offset (autofs-5.0+).
+ */
if (d_mountpoint(dentry)) {
DPRINTK("checking mountpoint %p %.*s",
dentry, (int)dentry->d_name.len, dentry->d_name.name);
- /* Can we expire this guy */
- if (!autofs4_can_expire(dentry, timeout, do_now))
+ /* Can we umount this guy */
+ if (autofs4_mount_busy(mnt, dentry))
goto next;
- /* Can we umount this guy */
- if (autofs4_check_mount(mnt, dentry)) {
+ /* Can we expire this guy */
+ if (autofs4_can_expire(dentry, timeout, do_now)) {
expired = dentry;
break;
}
goto next;
}
- if ( simple_empty(dentry) )
+ if (simple_empty(dentry))
goto next;
/* Case 2: tree mount, expire iff entire tree is not busy */
if (!exp_leaves) {
/* Lock the tree as we must expire as a whole */
spin_lock(&sbi->fs_lock);
- if (autofs4_check_tree(mnt, dentry, timeout, do_now)) {
+ if (!autofs4_tree_busy(mnt, dentry, timeout, do_now)) {
struct autofs_info *inf = autofs4_dentry_ino(dentry);
/* Set this flag early to catch sys_chdir and the like */
break;
}
spin_unlock(&sbi->fs_lock);
- /* Case 3: direct mount, expire individual leaves */
+ /*
+ * Case 3: pseudo direct mount, expire individual leaves
+ * (autofs-4.1).
+ */
} else {
expired = autofs4_check_leaves(mnt, dentry, timeout, do_now);
if (expired) {
next = next->next;
}
- if ( expired ) {
+ if (expired) {
DPRINTK("returning %p %.*s",
expired, (int)expired->d_name.len, expired->d_name.name);
spin_lock(&dcache_lock);
list_del(&expired->d_parent->d_subdirs);
- list_add(&expired->d_parent->d_subdirs, &expired->d_child);
+ list_add(&expired->d_parent->d_subdirs, &expired->d_u.d_child);
spin_unlock(&dcache_lock);
return expired;
}
pkt.hdr.proto_version = sbi->version;
pkt.hdr.type = autofs_ptype_expire;
- if ((dentry = autofs4_expire(sb, mnt, sbi, 0)) == NULL)
+ if ((dentry = autofs4_expire_indirect(sb, mnt, sbi, 0)) == NULL)
return -EAGAIN;
pkt.len = dentry->d_name.len;
if (arg && get_user(do_now, arg))
return -EFAULT;
- if ((dentry = autofs4_expire(sb, mnt, sbi, do_now)) != NULL) {
- struct autofs_info *de_info = autofs4_dentry_ino(dentry);
+ if (sbi->type & AUTOFS_TYPE_DIRECT)
+ dentry = autofs4_expire_direct(sb, mnt, sbi, do_now);
+ else
+ dentry = autofs4_expire_indirect(sb, mnt, sbi, do_now);
+
+ if (dentry) {
+ struct autofs_info *ino = autofs4_dentry_ino(dentry);
/* This is synchronous because it makes the daemon a
little easier */
- de_info->flags |= AUTOFS_INF_EXPIRING;
+ ino->flags |= AUTOFS_INF_EXPIRING;
ret = autofs4_wait(sbi, dentry, NFY_EXPIRE);
- de_info->flags &= ~AUTOFS_INF_EXPIRING;
+ ino->flags &= ~AUTOFS_INF_EXPIRING;
dput(dentry);
}
-
+
return ret;
}
git://git.onelab.eu / linux-2.6.git / blobdiff