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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/afs/volume.c | |
download | kernel_samsung_smdk4412-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip kernel_samsung_smdk4412-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz kernel_samsung_smdk4412-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 |
Linux-2.6.12-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.c | 520 |
1 files changed, 520 insertions, 0 deletions
diff --git a/fs/afs/volume.c b/fs/afs/volume.c new file mode 100644 index 0000000..0ff4b86 --- /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 |