+++ /dev/null
-/* -*- 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;
- unsigned long timeout = sbi->exp_timeout;
-
- while (1) {
- struct path path;
- int umount_ok;
-
- 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 */
- path.dentry = ent->dentry;
-
- if (!path.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 (!path.dentry->d_inode) {
- dput(path.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(path.dentry->d_inode->i_mode) ||
- !d_mountpoint(path.dentry)) {
- DPRINTK(("autofs: not expirable (not a mounted directory): %s\n", ent->name));
- continue;
- }
- path.mnt = mnt;
- path_get(&path);
- if (!follow_down(&path)) {
- path_put(&path);
- DPRINTK(("autofs: not expirable (not a mounted directory): %s\n", ent->name));
- continue;
- }
- while (d_mountpoint(path.dentry) && follow_down(&path))
- ;
- umount_ok = may_umount(path.mnt);
- path_put(&path);
-
- if (umount_ok) {
- 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));
- }
- 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);
- }
- }
-}
projects / mv-sheeva.git / blobdiff