upload tizen1.0 sourceHEADmaster2.0alpha

1 files changed, 526 insertions, 0 deletions

diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
new file mode 100644
index 00000000..a796c941
--- /dev/null
+++ b/fs/autofs4/expire.c
@@ -0,0 +1,526 @@
+/* -*- c -*- --------------------------------------------------------------- *
+ *
+ * linux/fs/autofs/expire.c
+ *
+ *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
+ *  Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
+ *  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
+ * option, any later version, incorporated herein by reference.
+ *
+ * ------------------------------------------------------------------------- */
+
+#include "autofs_i.h"
+
+static unsigned long now;
+
+/* Check if a dentry can be expired */
+static inline int autofs4_can_expire(struct dentry *dentry,
+					unsigned long timeout, int do_now)
+{
+	struct autofs_info *ino = autofs4_dentry_ino(dentry);
+
+	/* dentry in the process of being deleted */
+	if (ino == NULL)
+		return 0;
+
+	/* No point expiring a pending mount */
+	if (ino->flags & AUTOFS_INF_PENDING)
+		return 0;
+
+	if (!do_now) {
+		/* Too young to die */
+		if (!timeout || time_after(ino->last_used + timeout, now))
+			return 0;
+
+		/* update last_used here :-
+		   - obviously makes sense if it is in use now
+		   - less obviously, prevents rapid-fire expire
+		     attempts if expire fails the first time */
+		ino->last_used = now;
+	}
+	return 1;
+}
+
+/* Check a mount point for busyness */
+static int autofs4_mount_busy(struct vfsmount *mnt, struct dentry *dentry)
+{
+	struct dentry *top = dentry;
+	struct path path = {.mnt = mnt, .dentry = dentry};
+	int status = 1;
+
+	DPRINTK("dentry %p %.*s",
+		dentry, (int)dentry->d_name.len, dentry->d_name.name);
+
+	path_get(&path);
+
+	if (!follow_down(&path))
+		goto done;
+
+	if (is_autofs4_dentry(path.dentry)) {
+		struct autofs_sb_info *sbi = autofs4_sbi(path.dentry->d_sb);
+
+		/* This is an autofs submount, we can't expire it */
+		if (autofs_type_indirect(sbi->type))
+			goto done;
+
+		/*
+		 * Otherwise it's an offset mount and we need to check
+		 * if we can umount its mount, if there is one.
+		 */
+		if (!d_mountpoint(path.dentry)) {
+			status = 0;
+			goto done;
+		}
+	}
+
+	/* Update the expiry counter if fs is busy */
+	if (!may_umount_tree(path.mnt)) {
+		struct autofs_info *ino = autofs4_dentry_ino(top);
+		ino->last_used = jiffies;
+		goto done;
+	}
+
+	status = 0;
+done:
+	DPRINTK("returning = %d", status);
+	path_put(&path);
+	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
+ */
+static int autofs4_tree_busy(struct vfsmount *mnt,
+	       		     struct dentry *top,
+			     unsigned long timeout,
+			     int do_now)
+{
+	struct autofs_info *top_ino = autofs4_dentry_ino(top);
+	struct dentry *p;
+
+	DPRINTK("top %p %.*s",
+		top, (int)top->d_name.len, top->d_name.name);
+
+	/* Negative dentry - give up */
+	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;
+
+		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
+		 * 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(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))
+		return 1;
+
+	return 0;
+}
+
+static struct dentry *autofs4_check_leaves(struct vfsmount *mnt,
+					   struct dentry *parent,
+					   unsigned long timeout,
+					   int do_now)
+{
+	struct dentry *p;
+
+	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;
+
+		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;
+
+			/* 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;
+}
+
+/* Check if we can expire a direct mount (possibly a tree) */
+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 (!root)
+		return NULL;
+
+	now = jiffies;
+	timeout = sbi->exp_timeout;
+
+	spin_lock(&sbi->fs_lock);
+	if (!autofs4_direct_busy(mnt, root, timeout, do_now)) {
+		struct autofs_info *ino = autofs4_dentry_ino(root);
+		if (d_mountpoint(root)) {
+			ino->flags |= AUTOFS_INF_MOUNTPOINT;
+			root->d_mounted--;
+		}
+		ino->flags |= AUTOFS_INF_EXPIRING;
+		init_completion(&ino->expire_complete);
+		spin_unlock(&sbi->fs_lock);
+		return root;
+	}
+	spin_unlock(&sbi->fs_lock);
+	dput(root);
+
+	return NULL;
+}
+
+/*
+ * Find an eligible tree to time-out
+ * A tree is eligible if :-
+ *  - it is unused by any user process
+ *  - it has been unused for exp_timeout time
+ */
+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;
+	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;
+	unsigned int ino_count;
+
+	if (!root)
+		return NULL;
+
+	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);
+
+		spin_lock(&sbi->fs_lock);
+		ino = autofs4_dentry_ino(dentry);
+
+		/*
+		 * 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);
+
+			/* Path walk currently on this dentry? */
+			ino_count = atomic_read(&ino->count) + 2;
+			if (atomic_read(&dentry->d_count) > ino_count)
+				goto next;
+
+			/* Can we umount this guy */
+			if (autofs4_mount_busy(mnt, dentry))
+				goto next;
+
+			/* Can we expire this guy */
+			if (autofs4_can_expire(dentry, timeout, do_now)) {
+				expired = dentry;
+				goto found;
+			}
+			goto next;
+		}
+
+		if (simple_empty(dentry))
+			goto next;
+
+		/* Case 2: tree mount, expire iff entire tree is not busy */
+		if (!exp_leaves) {
+			/* Path walk currently on this dentry? */
+			ino_count = atomic_read(&ino->count) + 1;
+			if (atomic_read(&dentry->d_count) > ino_count)
+				goto next;
+
+			if (!autofs4_tree_busy(mnt, dentry, timeout, do_now)) {
+				expired = dentry;
+				goto found;
+			}
+		/*
+		 * Case 3: pseudo direct mount, expire individual leaves
+		 *	   (autofs-4.1).
+		 */
+		} else {
+			/* Path walk currently on this dentry? */
+			ino_count = atomic_read(&ino->count) + 1;
+			if (atomic_read(&dentry->d_count) > ino_count)
+				goto next;
+
+			expired = autofs4_check_leaves(mnt, dentry, timeout, do_now);
+			if (expired) {
+				dput(dentry);
+				goto found;
+			}
+		}
+next:
+		spin_unlock(&sbi->fs_lock);
+		dput(dentry);
+		spin_lock(&dcache_lock);
+		next = next->next;
+	}
+	spin_unlock(&dcache_lock);
+	return NULL;
+
+found:
+	DPRINTK("returning %p %.*s",
+		expired, (int)expired->d_name.len, expired->d_name.name);
+	ino = autofs4_dentry_ino(expired);
+	ino->flags |= AUTOFS_INF_EXPIRING;
+	init_completion(&ino->expire_complete);
+	spin_unlock(&sbi->fs_lock);
+	spin_lock(&dcache_lock);
+	list_move(&expired->d_parent->d_subdirs, &expired->d_u.d_child);
+	spin_unlock(&dcache_lock);
+	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,
+		      struct autofs_sb_info *sbi,
+		      struct autofs_packet_expire __user *pkt_p)
+{
+	struct autofs_packet_expire pkt;
+	struct autofs_info *ino;
+	struct dentry *dentry;
+	int ret = 0;
+
+	memset(&pkt,0,sizeof pkt);
+
+	pkt.hdr.proto_version = sbi->version;
+	pkt.hdr.type = autofs_ptype_expire;
+
+	if ((dentry = autofs4_expire_indirect(sb, mnt, sbi, 0)) == NULL)
+		return -EAGAIN;
+
+	pkt.len = dentry->d_name.len;
+	memcpy(pkt.name, dentry->d_name.name, pkt.len);
+	pkt.name[pkt.len] = '\0';
+	dput(dentry);
+
+	if ( copy_to_user(pkt_p, &pkt, sizeof(struct autofs_packet_expire)) )
+		ret = -EFAULT;
+
+	spin_lock(&sbi->fs_lock);
+	ino = autofs4_dentry_ino(dentry);
+	ino->flags &= ~AUTOFS_INF_EXPIRING;
+	complete_all(&ino->expire_complete);
+	spin_unlock(&sbi->fs_lock);
+
+	return ret;
+}
+
+int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
+			    struct autofs_sb_info *sbi, int when)
+{
+	struct dentry *dentry;
+	int ret = -EAGAIN;
+
+	if (autofs_type_trigger(sbi->type))
+		dentry = autofs4_expire_direct(sb, mnt, sbi, when);
+	else
+		dentry = autofs4_expire_indirect(sb, mnt, sbi, when);
+
+	if (dentry) {
+		struct autofs_info *ino = autofs4_dentry_ino(dentry);
+
+		/* This is synchronous because it makes the daemon a
+                   little easier */
+		ret = autofs4_wait(sbi, dentry, NFY_EXPIRE);
+
+		spin_lock(&sbi->fs_lock);
+		if (ino->flags & AUTOFS_INF_MOUNTPOINT) {
+			sb->s_root->d_mounted++;
+			ino->flags &= ~AUTOFS_INF_MOUNTPOINT;
+		}
+		ino->flags &= ~AUTOFS_INF_EXPIRING;
+		complete_all(&ino->expire_complete);
+		spin_unlock(&sbi->fs_lock);
+		dput(dentry);
+	}
+
+	return ret;
+}
+
+/* Call repeatedly until it returns -EAGAIN, meaning there's nothing
+   more to be done */
+int autofs4_expire_multi(struct super_block *sb, struct vfsmount *mnt,
+			struct autofs_sb_info *sbi, int __user *arg)
+{
+	int do_now = 0;
+
+	if (arg && get_user(do_now, arg))
+		return -EFAULT;
+
+	return autofs4_do_expire_multi(sb, mnt, sbi, do_now);
+}
+