linux/fs/autofs/dirhash.c
Alexander Krizhanovsky f76baf9365 [PATCH] autofs: fix "busy inodes after umount..."
This patch for old autofs (version 3) cleans dentries which are not putted
after killing the automount daemon (it's analogue of recent patch for
autofs4).

Signed-off-by: Alexander Krizhanovsky <klx@yandex.ru>
Cc: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 13:57:31 -07:00

250 lines
6.3 KiB
C

/* -*- linux-c -*- --------------------------------------------------------- *
*
* linux/fs/autofs/dirhash.c
*
* Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
*
* 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"
/* Functions for maintenance of expiry queue */
static void autofs_init_usage(struct autofs_dirhash *dh,
struct autofs_dir_ent *ent)
{
list_add_tail(&ent->exp, &dh->expiry_head);
ent->last_usage = jiffies;
}
static void autofs_delete_usage(struct autofs_dir_ent *ent)
{
list_del(&ent->exp);
}
void autofs_update_usage(struct autofs_dirhash *dh,
struct autofs_dir_ent *ent)
{
autofs_delete_usage(ent); /* Unlink from current position */
autofs_init_usage(dh,ent); /* Relink at queue tail */
}
struct autofs_dir_ent *autofs_expire(struct super_block *sb,
struct autofs_sb_info *sbi,
struct vfsmount *mnt)
{
struct autofs_dirhash *dh = &sbi->dirhash;
struct autofs_dir_ent *ent;
struct dentry *dentry;
unsigned long timeout = sbi->exp_timeout;
while (1) {
if ( list_empty(&dh->expiry_head) || sbi->catatonic )
return NULL; /* No entries */
/* We keep the list sorted by last_usage and want old stuff */
ent = list_entry(dh->expiry_head.next, struct autofs_dir_ent, exp);
if (jiffies - ent->last_usage < timeout)
break;
/* Move to end of list in case expiry isn't desirable */
autofs_update_usage(dh, ent);
/* Check to see that entry is expirable */
if ( ent->ino < AUTOFS_FIRST_DIR_INO )
return ent; /* Symlinks are always expirable */
/* Get the dentry for the autofs subdirectory */
dentry = ent->dentry;
if ( !dentry ) {
/* Should only happen in catatonic mode */
printk("autofs: dentry == NULL but inode range is directory, entry %s\n", ent->name);
autofs_delete_usage(ent);
continue;
}
if ( !dentry->d_inode ) {
dput(dentry);
printk("autofs: negative dentry on expiry queue: %s\n",
ent->name);
autofs_delete_usage(ent);
continue;
}
/* Make sure entry is mounted and unused; note that dentry will
point to the mounted-on-top root. */
if (!S_ISDIR(dentry->d_inode->i_mode)||!d_mountpoint(dentry)) {
DPRINTK(("autofs: not expirable (not a mounted directory): %s\n", ent->name));
continue;
}
mntget(mnt);
dget(dentry);
if (!follow_down(&mnt, &dentry)) {
dput(dentry);
mntput(mnt);
DPRINTK(("autofs: not expirable (not a mounted directory): %s\n", ent->name));
continue;
}
while (d_mountpoint(dentry) && follow_down(&mnt, &dentry))
;
dput(dentry);
if ( may_umount(mnt) == 0 ) {
mntput(mnt);
DPRINTK(("autofs: signaling expire on %s\n", ent->name));
return ent; /* Expirable! */
}
DPRINTK(("autofs: didn't expire due to may_umount: %s\n", ent->name));
mntput(mnt);
}
return NULL; /* No expirable entries */
}
void autofs_initialize_hash(struct autofs_dirhash *dh) {
memset(&dh->h, 0, AUTOFS_HASH_SIZE*sizeof(struct autofs_dir_ent *));
INIT_LIST_HEAD(&dh->expiry_head);
}
struct autofs_dir_ent *autofs_hash_lookup(const struct autofs_dirhash *dh, struct qstr *name)
{
struct autofs_dir_ent *dhn;
DPRINTK(("autofs_hash_lookup: hash = 0x%08x, name = ", name->hash));
autofs_say(name->name,name->len);
for ( dhn = dh->h[(unsigned) name->hash % AUTOFS_HASH_SIZE] ; dhn ; dhn = dhn->next ) {
if ( name->hash == dhn->hash &&
name->len == dhn->len &&
!memcmp(name->name, dhn->name, name->len) )
break;
}
return dhn;
}
void autofs_hash_insert(struct autofs_dirhash *dh, struct autofs_dir_ent *ent)
{
struct autofs_dir_ent **dhnp;
DPRINTK(("autofs_hash_insert: hash = 0x%08x, name = ", ent->hash));
autofs_say(ent->name,ent->len);
autofs_init_usage(dh,ent);
if (ent->dentry)
dget(ent->dentry);
dhnp = &dh->h[(unsigned) ent->hash % AUTOFS_HASH_SIZE];
ent->next = *dhnp;
ent->back = dhnp;
*dhnp = ent;
if ( ent->next )
ent->next->back = &(ent->next);
}
void autofs_hash_delete(struct autofs_dir_ent *ent)
{
*(ent->back) = ent->next;
if ( ent->next )
ent->next->back = ent->back;
autofs_delete_usage(ent);
if ( ent->dentry )
dput(ent->dentry);
kfree(ent->name);
kfree(ent);
}
/*
* Used by readdir(). We must validate "ptr", so we can't simply make it
* a pointer. Values below 0xffff are reserved; calling with any value
* <= 0x10000 will return the first entry found.
*
* "last" can be NULL or the value returned by the last search *if* we
* want the next sequential entry.
*/
struct autofs_dir_ent *autofs_hash_enum(const struct autofs_dirhash *dh,
off_t *ptr, struct autofs_dir_ent *last)
{
int bucket, ecount, i;
struct autofs_dir_ent *ent;
bucket = (*ptr >> 16) - 1;
ecount = *ptr & 0xffff;
if ( bucket < 0 ) {
bucket = ecount = 0;
}
DPRINTK(("autofs_hash_enum: bucket %d, entry %d\n", bucket, ecount));
ent = last ? last->next : NULL;
if ( ent ) {
ecount++;
} else {
while ( bucket < AUTOFS_HASH_SIZE ) {
ent = dh->h[bucket];
for ( i = ecount ; ent && i ; i-- )
ent = ent->next;
if (ent) {
ecount++; /* Point to *next* entry */
break;
}
bucket++; ecount = 0;
}
}
#ifdef DEBUG
if ( !ent )
printk("autofs_hash_enum: nothing found\n");
else {
printk("autofs_hash_enum: found hash %08x, name", ent->hash);
autofs_say(ent->name,ent->len);
}
#endif
*ptr = ((bucket+1) << 16) + ecount;
return ent;
}
/* Iterate over all the ents, and remove all dentry pointers. Used on
entering catatonic mode, in order to make the filesystem unmountable. */
void autofs_hash_dputall(struct autofs_dirhash *dh)
{
int i;
struct autofs_dir_ent *ent;
for ( i = 0 ; i < AUTOFS_HASH_SIZE ; i++ ) {
for ( ent = dh->h[i] ; ent ; ent = ent->next ) {
if ( ent->dentry ) {
dput(ent->dentry);
ent->dentry = NULL;
}
}
}
}
/* Delete everything. This is used on filesystem destruction, so we
make no attempt to keep the pointers valid */
void autofs_hash_nuke(struct autofs_sb_info *sbi)
{
int i;
struct autofs_dir_ent *ent, *nent;
for ( i = 0 ; i < AUTOFS_HASH_SIZE ; i++ ) {
for ( ent = sbi->dirhash.h[i] ; ent ; ent = nent ) {
nent = ent->next;
if ( ent->dentry )
dput(ent->dentry);
kfree(ent->name);
kfree(ent);
}
}
shrink_dcache_sb(sbi->sb);
}