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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-17 02:20:36 +0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-17 02:20:36 +0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/afs/volume.c
downloadlinux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'fs/afs/volume.c')
-rw-r--r--fs/afs/volume.c520
1 files changed, 520 insertions, 0 deletions
diff --git a/fs/afs/volume.c b/fs/afs/volume.c
new file mode 100644
index 000000000000..0ff4b86476e3
--- /dev/null
+++ b/fs/afs/volume.c
@@ -0,0 +1,520 @@
+/* volume.c: AFS volume management
+ *
+ * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include "volume.h"
+#include "vnode.h"
+#include "cell.h"
+#include "cache.h"
+#include "cmservice.h"
+#include "fsclient.h"
+#include "vlclient.h"
+#include "internal.h"
+
+#ifdef __KDEBUG
+static const char *afs_voltypes[] = { "R/W", "R/O", "BAK" };
+#endif
+
+#ifdef AFS_CACHING_SUPPORT
+static cachefs_match_val_t afs_volume_cache_match(void *target,
+ const void *entry);
+static void afs_volume_cache_update(void *source, void *entry);
+
+struct cachefs_index_def afs_volume_cache_index_def = {
+ .name = "volume",
+ .data_size = sizeof(struct afs_cache_vhash),
+ .keys[0] = { CACHEFS_INDEX_KEYS_BIN, 1 },
+ .keys[1] = { CACHEFS_INDEX_KEYS_BIN, 1 },
+ .match = afs_volume_cache_match,
+ .update = afs_volume_cache_update,
+};
+#endif
+
+/*****************************************************************************/
+/*
+ * lookup a volume by name
+ * - this can be one of the following:
+ * "%[cell:]volume[.]" R/W volume
+ * "#[cell:]volume[.]" R/O or R/W volume (rwparent=0),
+ * or R/W (rwparent=1) volume
+ * "%[cell:]volume.readonly" R/O volume
+ * "#[cell:]volume.readonly" R/O volume
+ * "%[cell:]volume.backup" Backup volume
+ * "#[cell:]volume.backup" Backup volume
+ *
+ * The cell name is optional, and defaults to the current cell.
+ *
+ * See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin
+ * Guide
+ * - Rule 1: Explicit type suffix forces access of that type or nothing
+ * (no suffix, then use Rule 2 & 3)
+ * - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W
+ * if not available
+ * - Rule 3: If parent volume is R/W, then only mount R/W volume unless
+ * explicitly told otherwise
+ */
+int afs_volume_lookup(const char *name, struct afs_cell *cell, int rwpath,
+ struct afs_volume **_volume)
+{
+ struct afs_vlocation *vlocation = NULL;
+ struct afs_volume *volume = NULL;
+ afs_voltype_t type;
+ const char *cellname, *volname, *suffix;
+ char srvtmask;
+ int force, ret, loop, cellnamesz, volnamesz;
+
+ _enter("%s,,%d,", name, rwpath);
+
+ if (!name || (name[0] != '%' && name[0] != '#') || !name[1]) {
+ printk("kAFS: unparsable volume name\n");
+ return -EINVAL;
+ }
+
+ /* determine the type of volume we're looking for */
+ force = 0;
+ type = AFSVL_ROVOL;
+
+ if (rwpath || name[0] == '%') {
+ type = AFSVL_RWVOL;
+ force = 1;
+ }
+
+ suffix = strrchr(name, '.');
+ if (suffix) {
+ if (strcmp(suffix, ".readonly") == 0) {
+ type = AFSVL_ROVOL;
+ force = 1;
+ }
+ else if (strcmp(suffix, ".backup") == 0) {
+ type = AFSVL_BACKVOL;
+ force = 1;
+ }
+ else if (suffix[1] == 0) {
+ }
+ else {
+ suffix = NULL;
+ }
+ }
+
+ /* split the cell and volume names */
+ name++;
+ volname = strchr(name, ':');
+ if (volname) {
+ cellname = name;
+ cellnamesz = volname - name;
+ volname++;
+ }
+ else {
+ volname = name;
+ cellname = NULL;
+ cellnamesz = 0;
+ }
+
+ volnamesz = suffix ? suffix - volname : strlen(volname);
+
+ _debug("CELL:%*.*s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
+ cellnamesz, cellnamesz, cellname ?: "", cell,
+ volnamesz, volnamesz, volname, suffix ?: "-",
+ type,
+ force ? " FORCE" : "");
+
+ /* lookup the cell record */
+ if (cellname || !cell) {
+ ret = afs_cell_lookup(cellname, cellnamesz, &cell);
+ if (ret<0) {
+ printk("kAFS: unable to lookup cell '%s'\n",
+ cellname ?: "");
+ goto error;
+ }
+ }
+ else {
+ afs_get_cell(cell);
+ }
+
+ /* lookup the volume location record */
+ ret = afs_vlocation_lookup(cell, volname, volnamesz, &vlocation);
+ if (ret < 0)
+ goto error;
+
+ /* make the final decision on the type we want */
+ ret = -ENOMEDIUM;
+ if (force && !(vlocation->vldb.vidmask & (1 << type)))
+ goto error;
+
+ srvtmask = 0;
+ for (loop = 0; loop < vlocation->vldb.nservers; loop++)
+ srvtmask |= vlocation->vldb.srvtmask[loop];
+
+ if (force) {
+ if (!(srvtmask & (1 << type)))
+ goto error;
+ }
+ else if (srvtmask & AFS_VOL_VTM_RO) {
+ type = AFSVL_ROVOL;
+ }
+ else if (srvtmask & AFS_VOL_VTM_RW) {
+ type = AFSVL_RWVOL;
+ }
+ else {
+ goto error;
+ }
+
+ down_write(&cell->vl_sem);
+
+ /* is the volume already active? */
+ if (vlocation->vols[type]) {
+ /* yes - re-use it */
+ volume = vlocation->vols[type];
+ afs_get_volume(volume);
+ goto success;
+ }
+
+ /* create a new volume record */
+ _debug("creating new volume record");
+
+ ret = -ENOMEM;
+ volume = kmalloc(sizeof(struct afs_volume), GFP_KERNEL);
+ if (!volume)
+ goto error_up;
+
+ memset(volume, 0, sizeof(struct afs_volume));
+ atomic_set(&volume->usage, 1);
+ volume->type = type;
+ volume->type_force = force;
+ volume->cell = cell;
+ volume->vid = vlocation->vldb.vid[type];
+
+ init_rwsem(&volume->server_sem);
+
+ /* look up all the applicable server records */
+ for (loop = 0; loop < 8; loop++) {
+ if (vlocation->vldb.srvtmask[loop] & (1 << volume->type)) {
+ ret = afs_server_lookup(
+ volume->cell,
+ &vlocation->vldb.servers[loop],
+ &volume->servers[volume->nservers]);
+ if (ret < 0)
+ goto error_discard;
+
+ volume->nservers++;
+ }
+ }
+
+ /* attach the cache and volume location */
+#ifdef AFS_CACHING_SUPPORT
+ cachefs_acquire_cookie(vlocation->cache,
+ &afs_vnode_cache_index_def,
+ volume,
+ &volume->cache);
+#endif
+
+ afs_get_vlocation(vlocation);
+ volume->vlocation = vlocation;
+
+ vlocation->vols[type] = volume;
+
+ success:
+ _debug("kAFS selected %s volume %08x",
+ afs_voltypes[volume->type], volume->vid);
+ *_volume = volume;
+ ret = 0;
+
+ /* clean up */
+ error_up:
+ up_write(&cell->vl_sem);
+ error:
+ afs_put_vlocation(vlocation);
+ afs_put_cell(cell);
+
+ _leave(" = %d (%p)", ret, volume);
+ return ret;
+
+ error_discard:
+ up_write(&cell->vl_sem);
+
+ for (loop = volume->nservers - 1; loop >= 0; loop--)
+ afs_put_server(volume->servers[loop]);
+
+ kfree(volume);
+ goto error;
+} /* end afs_volume_lookup() */
+
+/*****************************************************************************/
+/*
+ * destroy a volume record
+ */
+void afs_put_volume(struct afs_volume *volume)
+{
+ struct afs_vlocation *vlocation;
+ int loop;
+
+ if (!volume)
+ return;
+
+ _enter("%p", volume);
+
+ vlocation = volume->vlocation;
+
+ /* sanity check */
+ BUG_ON(atomic_read(&volume->usage) <= 0);
+
+ /* to prevent a race, the decrement and the dequeue must be effectively
+ * atomic */
+ down_write(&vlocation->cell->vl_sem);
+
+ if (likely(!atomic_dec_and_test(&volume->usage))) {
+ up_write(&vlocation->cell->vl_sem);
+ _leave("");
+ return;
+ }
+
+ vlocation->vols[volume->type] = NULL;
+
+ up_write(&vlocation->cell->vl_sem);
+
+ /* finish cleaning up the volume */
+#ifdef AFS_CACHING_SUPPORT
+ cachefs_relinquish_cookie(volume->cache, 0);
+#endif
+ afs_put_vlocation(vlocation);
+
+ for (loop = volume->nservers - 1; loop >= 0; loop--)
+ afs_put_server(volume->servers[loop]);
+
+ kfree(volume);
+
+ _leave(" [destroyed]");
+} /* end afs_put_volume() */
+
+/*****************************************************************************/
+/*
+ * pick a server to use to try accessing this volume
+ * - returns with an elevated usage count on the server chosen
+ */
+int afs_volume_pick_fileserver(struct afs_volume *volume,
+ struct afs_server **_server)
+{
+ struct afs_server *server;
+ int ret, state, loop;
+
+ _enter("%s", volume->vlocation->vldb.name);
+
+ down_read(&volume->server_sem);
+
+ /* handle the no-server case */
+ if (volume->nservers == 0) {
+ ret = volume->rjservers ? -ENOMEDIUM : -ESTALE;
+ up_read(&volume->server_sem);
+ _leave(" = %d [no servers]", ret);
+ return ret;
+ }
+
+ /* basically, just search the list for the first live server and use
+ * that */
+ ret = 0;
+ for (loop = 0; loop < volume->nservers; loop++) {
+ server = volume->servers[loop];
+ state = server->fs_state;
+
+ switch (state) {
+ /* found an apparently healthy server */
+ case 0:
+ afs_get_server(server);
+ up_read(&volume->server_sem);
+ *_server = server;
+ _leave(" = 0 (picked %08x)",
+ ntohl(server->addr.s_addr));
+ return 0;
+
+ case -ENETUNREACH:
+ if (ret == 0)
+ ret = state;
+ break;
+
+ case -EHOSTUNREACH:
+ if (ret == 0 ||
+ ret == -ENETUNREACH)
+ ret = state;
+ break;
+
+ case -ECONNREFUSED:
+ if (ret == 0 ||
+ ret == -ENETUNREACH ||
+ ret == -EHOSTUNREACH)
+ ret = state;
+ break;
+
+ default:
+ case -EREMOTEIO:
+ if (ret == 0 ||
+ ret == -ENETUNREACH ||
+ ret == -EHOSTUNREACH ||
+ ret == -ECONNREFUSED)
+ ret = state;
+ break;
+ }
+ }
+
+ /* no available servers
+ * - TODO: handle the no active servers case better
+ */
+ up_read(&volume->server_sem);
+ _leave(" = %d", ret);
+ return ret;
+} /* end afs_volume_pick_fileserver() */
+
+/*****************************************************************************/
+/*
+ * release a server after use
+ * - releases the ref on the server struct that was acquired by picking
+ * - records result of using a particular server to access a volume
+ * - return 0 to try again, 1 if okay or to issue error
+ */
+int afs_volume_release_fileserver(struct afs_volume *volume,
+ struct afs_server *server,
+ int result)
+{
+ unsigned loop;
+
+ _enter("%s,%08x,%d",
+ volume->vlocation->vldb.name, ntohl(server->addr.s_addr),
+ result);
+
+ switch (result) {
+ /* success */
+ case 0:
+ server->fs_act_jif = jiffies;
+ break;
+
+ /* the fileserver denied all knowledge of the volume */
+ case -ENOMEDIUM:
+ server->fs_act_jif = jiffies;
+ down_write(&volume->server_sem);
+
+ /* first, find where the server is in the active list (if it
+ * is) */
+ for (loop = 0; loop < volume->nservers; loop++)
+ if (volume->servers[loop] == server)
+ goto present;
+
+ /* no longer there - may have been discarded by another op */
+ goto try_next_server_upw;
+
+ present:
+ volume->nservers--;
+ memmove(&volume->servers[loop],
+ &volume->servers[loop + 1],
+ sizeof(volume->servers[loop]) *
+ (volume->nservers - loop));
+ volume->servers[volume->nservers] = NULL;
+ afs_put_server(server);
+ volume->rjservers++;
+
+ if (volume->nservers > 0)
+ /* another server might acknowledge its existence */
+ goto try_next_server_upw;
+
+ /* handle the case where all the fileservers have rejected the
+ * volume
+ * - TODO: try asking the fileservers for volume information
+ * - TODO: contact the VL server again to see if the volume is
+ * no longer registered
+ */
+ up_write(&volume->server_sem);
+ afs_put_server(server);
+ _leave(" [completely rejected]");
+ return 1;
+
+ /* problem reaching the server */
+ case -ENETUNREACH:
+ case -EHOSTUNREACH:
+ case -ECONNREFUSED:
+ case -ETIMEDOUT:
+ case -EREMOTEIO:
+ /* mark the server as dead
+ * TODO: vary dead timeout depending on error
+ */
+ spin_lock(&server->fs_lock);
+ if (!server->fs_state) {
+ server->fs_dead_jif = jiffies + HZ * 10;
+ server->fs_state = result;
+ printk("kAFS: SERVER DEAD state=%d\n", result);
+ }
+ spin_unlock(&server->fs_lock);
+ goto try_next_server;
+
+ /* miscellaneous error */
+ default:
+ server->fs_act_jif = jiffies;
+ case -ENOMEM:
+ case -ENONET:
+ break;
+ }
+
+ /* tell the caller to accept the result */
+ afs_put_server(server);
+ _leave("");
+ return 1;
+
+ /* tell the caller to loop around and try the next server */
+ try_next_server_upw:
+ up_write(&volume->server_sem);
+ try_next_server:
+ afs_put_server(server);
+ _leave(" [try next server]");
+ return 0;
+
+} /* end afs_volume_release_fileserver() */
+
+/*****************************************************************************/
+/*
+ * match a volume hash record stored in the cache
+ */
+#ifdef AFS_CACHING_SUPPORT
+static cachefs_match_val_t afs_volume_cache_match(void *target,
+ const void *entry)
+{
+ const struct afs_cache_vhash *vhash = entry;
+ struct afs_volume *volume = target;
+
+ _enter("{%u},{%u}", volume->type, vhash->vtype);
+
+ if (volume->type == vhash->vtype) {
+ _leave(" = SUCCESS");
+ return CACHEFS_MATCH_SUCCESS;
+ }
+
+ _leave(" = FAILED");
+ return CACHEFS_MATCH_FAILED;
+} /* end afs_volume_cache_match() */
+#endif
+
+/*****************************************************************************/
+/*
+ * update a volume hash record stored in the cache
+ */
+#ifdef AFS_CACHING_SUPPORT
+static void afs_volume_cache_update(void *source, void *entry)
+{
+ struct afs_cache_vhash *vhash = entry;
+ struct afs_volume *volume = source;
+
+ _enter("");
+
+ vhash->vtype = volume->type;
+
+} /* end afs_volume_cache_update() */
+#endif