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linux/fs/afs/vnode.c
David Howells 8b2a464ced afs: Add an address list concept 
Add an RCU replaceable address list structure to hold a list of server
addresses.  The list also holds the

To this end:

 (1) A cell's VL server address list can be loaded directly via insmod or
     echo to /proc/fs/afs/cells or dynamically from a DNS query for AFSDB
     or SRV records.

 (2) Anyone wanting to use a cell's VL server address must wait until the
     cell record comes online and has tried to obtain some addresses.

 (3) An FS server's address list, for the moment, has a single entry that
     is the key to the server list.  This will change in the future when a
     server is instead keyed on its UUID and the VL.GetAddrsU operation is
     used.

 (4) An 'address cursor' concept is introduced to handle iteration through
     the address list.  This is passed to the afs_make_call() as, in the
     future, stuff (such as abort code) that doesn't outlast the call will
     be returned in it.

In the future, we might want to annotate the list with information about
how each address fares.  We might then want to propagate such annotations
over address list replacement.

Whilst we're at it, we allow IPv6 addresses to be specified in
colon-delimited lists by enclosing them in square brackets.

Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-13 15:38:18 +00:00

750 lines
18 KiB
C
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/* AFS vnode management
*
* Copyright (C) 2002, 2007 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/fs.h>
#include <linux/sched.h>
#include "internal.h"
/*
* Handle remote file deletion.
*/
static void afs_vnode_deleted_remotely(struct afs_vnode *vnode)
{
struct afs_cb_interest *cbi = vnode->cb_interest;
_enter("{%p}", cbi);
set_bit(AFS_VNODE_DELETED, &vnode->flags);
if (cbi) {
vnode->cb_interest = NULL;
afs_put_cb_interest(afs_v2net(vnode), cbi);
}
_leave("");
}
/*
* finish off updating the recorded status of a file after a successful
* operation completion
* - starts callback expiry timer
* - adds to server's callback list
*/
void afs_vnode_finalise_status_update(struct afs_vnode *vnode,
struct afs_server *server)
{
spin_lock(&vnode->lock);
vnode->update_cnt--;
ASSERTCMP(vnode->update_cnt, >=, 0);
spin_unlock(&vnode->lock);
wake_up_all(&vnode->update_waitq);
_leave("");
}
/*
* finish off updating the recorded status of a file after an operation failed
*/
static void afs_vnode_status_update_failed(struct afs_fs_cursor *fc,
struct afs_vnode *vnode)
{
_enter("{%x:%u},%d", vnode->fid.vid, vnode->fid.vnode, fc->ac.error);
spin_lock(&vnode->lock);
if (fc->ac.error == -ENOENT) {
/* the file was deleted on the server */
_debug("got NOENT from server - marking file deleted");
afs_vnode_deleted_remotely(vnode);
}
vnode->update_cnt--;
ASSERTCMP(vnode->update_cnt, >=, 0);
spin_unlock(&vnode->lock);
wake_up_all(&vnode->update_waitq);
_leave("");
}
/*
* fetch file status from the volume
* - don't issue a fetch if:
* - the changed bit is not set and there's a valid callback
* - there are any outstanding ops that will fetch the status
* - TODO implement local caching
*/
int afs_vnode_fetch_status(struct afs_vnode *vnode, struct key *key, bool force)
{
struct afs_fs_cursor fc;
unsigned int cb_break = 0;
DECLARE_WAITQUEUE(myself, current);
_enter("%s,{%x:%u.%u,S=%lx},%u",
vnode->volume->vlocation->vldb.name,
vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique,
vnode->flags,
force);
if (!force && test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
_leave(" [unchanged]");
return 0;
}
if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
_leave(" [deleted]");
return -ENOENT;
}
cb_break = vnode->cb_break + vnode->cb_s_break;
spin_lock(&vnode->lock);
if (!force && test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
spin_unlock(&vnode->lock);
_leave(" [unchanged]");
return 0;
}
ASSERTCMP(vnode->update_cnt, >=, 0);
if (vnode->update_cnt > 0) {
/* someone else started a fetch */
_debug("wait on fetch %d", vnode->update_cnt);
set_current_state(TASK_UNINTERRUPTIBLE);
ASSERT(myself.func != NULL);
add_wait_queue(&vnode->update_waitq, &myself);
/* wait for the status to be updated */
for (;;) {
if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags))
break;
if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
break;
/* check to see if it got updated and invalidated all
* before we saw it */
if (vnode->update_cnt == 0) {
remove_wait_queue(&vnode->update_waitq,
&myself);
set_current_state(TASK_RUNNING);
goto get_anyway;
}
spin_unlock(&vnode->lock);
schedule();
set_current_state(TASK_UNINTERRUPTIBLE);
spin_lock(&vnode->lock);
}
remove_wait_queue(&vnode->update_waitq, &myself);
spin_unlock(&vnode->lock);
set_current_state(TASK_RUNNING);
return test_bit(AFS_VNODE_DELETED, &vnode->flags) ?
-ENOENT : 0;
}
get_anyway:
/* okay... we're going to have to initiate the op */
vnode->update_cnt++;
spin_unlock(&vnode->lock);
/* merge AFS status fetches and clear outstanding callback on this
* vnode */
afs_init_fs_cursor(&fc, vnode);
do {
/* pick a server to query */
if (!afs_volume_pick_fileserver(&fc, vnode))
goto no_server;
fc.ac.error = afs_fs_fetch_file_status(&fc, key, vnode, NULL, false);
} while (afs_iterate_fs_cursor(&fc, vnode));
/* adjust the flags */
if (fc.ac.error == 0) {
_debug("adjust");
afs_cache_permit(vnode, key, cb_break);
afs_vnode_finalise_status_update(vnode, fc.server);
} else {
_debug("failed [%d]", fc.ac.error);
afs_vnode_status_update_failed(&fc, vnode);
}
out:
afs_end_fs_cursor(&fc, afs_v2net(vnode));
ASSERTCMP(vnode->update_cnt, >=, 0);
_leave(" = %d [cnt %d]", fc.ac.error, vnode->update_cnt);
return fc.ac.error;
no_server:
spin_lock(&vnode->lock);
vnode->update_cnt--;
spin_unlock(&vnode->lock);
goto out;
}
/*
* fetch file data from the volume
* - TODO implement caching
*/
int afs_vnode_fetch_data(struct afs_vnode *vnode, struct key *key,
struct afs_read *desc)
{
struct afs_fs_cursor fc;
_enter("%s{%x:%u.%u},%x,,,",
vnode->volume->vlocation->vldb.name,
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique,
key_serial(key));
/* this op will fetch the status */
spin_lock(&vnode->lock);
vnode->update_cnt++;
spin_unlock(&vnode->lock);
/* merge in AFS status fetches and clear outstanding callback on this
* vnode */
afs_init_fs_cursor(&fc, vnode);
do {
/* pick a server to query */
if (!afs_volume_pick_fileserver(&fc, vnode))
goto no_server;
fc.ac.error = afs_fs_fetch_data(&fc, key, vnode, desc, false);
} while (afs_iterate_fs_cursor(&fc, vnode));
/* adjust the flags */
if (fc.ac.error == 0)
afs_vnode_finalise_status_update(vnode, fc.server);
else
afs_vnode_status_update_failed(&fc, vnode);
out:
return afs_end_fs_cursor(&fc, afs_v2net(vnode));
no_server:
spin_lock(&vnode->lock);
vnode->update_cnt--;
ASSERTCMP(vnode->update_cnt, >=, 0);
spin_unlock(&vnode->lock);
goto out;
}
/*
* make a file or a directory
*/
int afs_vnode_create(struct afs_vnode *vnode, struct key *key,
const char *name, umode_t mode, struct afs_fid *newfid,
struct afs_file_status *newstatus,
struct afs_callback *newcb, struct afs_server **_server)
{
struct afs_fs_cursor fc;
_enter("%s{%x:%u.%u},%x,%s,,",
vnode->volume->vlocation->vldb.name,
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique,
key_serial(key),
name);
/* this op will fetch the status on the directory we're creating in */
spin_lock(&vnode->lock);
vnode->update_cnt++;
spin_unlock(&vnode->lock);
afs_init_fs_cursor(&fc, vnode);
do {
/* pick a server to query */
if (!afs_volume_pick_fileserver(&fc, vnode))
goto no_server;
fc.ac.error = afs_fs_create(&fc, key, vnode, name, mode, newfid,
newstatus, newcb, false);
} while (afs_iterate_fs_cursor(&fc, vnode));
/* adjust the flags */
if (fc.ac.error == 0) {
afs_vnode_finalise_status_update(vnode, fc.server);
*_server = fc.server;
fc.server = NULL;
} else {
afs_vnode_status_update_failed(&fc, vnode);
*_server = NULL;
}
out:
return afs_end_fs_cursor(&fc, afs_v2net(vnode));
no_server:
spin_lock(&vnode->lock);
vnode->update_cnt--;
ASSERTCMP(vnode->update_cnt, >=, 0);
spin_unlock(&vnode->lock);
goto out;
}
/*
* remove a file or directory
*/
int afs_vnode_remove(struct afs_vnode *vnode, struct key *key, const char *name,
bool isdir)
{
struct afs_fs_cursor fc;
_enter("%s{%x:%u.%u},%x,%s",
vnode->volume->vlocation->vldb.name,
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique,
key_serial(key),
name);
/* this op will fetch the status on the directory we're removing from */
spin_lock(&vnode->lock);
vnode->update_cnt++;
spin_unlock(&vnode->lock);
afs_init_fs_cursor(&fc, vnode);
do {
/* pick a server to query */
if (!afs_volume_pick_fileserver(&fc, vnode))
goto no_server;
fc.ac.error = afs_fs_remove(&fc, key, vnode, name, isdir, false);
} while (afs_iterate_fs_cursor(&fc, vnode));
/* adjust the flags */
if (fc.ac.error == 0)
afs_vnode_finalise_status_update(vnode, fc.server);
else
afs_vnode_status_update_failed(&fc, vnode);
out:
return afs_end_fs_cursor(&fc, afs_v2net(vnode));
no_server:
spin_lock(&vnode->lock);
vnode->update_cnt--;
ASSERTCMP(vnode->update_cnt, >=, 0);
spin_unlock(&vnode->lock);
goto out;
}
/*
* create a hard link
*/
int afs_vnode_link(struct afs_vnode *dvnode, struct afs_vnode *vnode,
struct key *key, const char *name)
{
struct afs_fs_cursor fc;
_enter("%s{%x:%u.%u},%s{%x:%u.%u},%x,%s",
dvnode->volume->vlocation->vldb.name,
dvnode->fid.vid,
dvnode->fid.vnode,
dvnode->fid.unique,
vnode->volume->vlocation->vldb.name,
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique,
key_serial(key),
name);
/* this op will fetch the status on the directory we're removing from */
spin_lock(&vnode->lock);
vnode->update_cnt++;
spin_unlock(&vnode->lock);
spin_lock(&dvnode->lock);
dvnode->update_cnt++;
spin_unlock(&dvnode->lock);
afs_init_fs_cursor(&fc, vnode);
do {
/* pick a server to query */
if (!afs_volume_pick_fileserver(&fc, dvnode))
goto no_server;
fc.ac.error = afs_fs_link(&fc, key, dvnode, vnode, name, false);
} while (afs_iterate_fs_cursor(&fc, dvnode));
/* adjust the flags */
if (fc.ac.error == 0) {
afs_vnode_finalise_status_update(vnode, fc.server);
afs_vnode_finalise_status_update(dvnode, fc.server);
} else {
afs_vnode_status_update_failed(&fc, vnode);
afs_vnode_status_update_failed(&fc, dvnode);
}
out:
return afs_end_fs_cursor(&fc, afs_v2net(vnode));
no_server:
spin_lock(&vnode->lock);
vnode->update_cnt--;
ASSERTCMP(vnode->update_cnt, >=, 0);
spin_unlock(&vnode->lock);
spin_lock(&dvnode->lock);
dvnode->update_cnt--;
ASSERTCMP(dvnode->update_cnt, >=, 0);
spin_unlock(&dvnode->lock);
goto out;
}
/*
* create a symbolic link
*/
int afs_vnode_symlink(struct afs_vnode *vnode, struct key *key,
const char *name, const char *content,
struct afs_fid *newfid,
struct afs_file_status *newstatus,
struct afs_server **_server)
{
struct afs_fs_cursor fc;
_enter("%s{%x:%u.%u},%x,%s,%s,,,",
vnode->volume->vlocation->vldb.name,
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique,
key_serial(key),
name, content);
/* this op will fetch the status on the directory we're creating in */
spin_lock(&vnode->lock);
vnode->update_cnt++;
spin_unlock(&vnode->lock);
afs_init_fs_cursor(&fc, vnode);
do {
/* pick a server to query */
if (!afs_volume_pick_fileserver(&fc, vnode))
goto no_server;
fc.ac.error = afs_fs_symlink(&fc, key, vnode, name, content,
newfid, newstatus, false);
} while (afs_iterate_fs_cursor(&fc, vnode));
/* adjust the flags */
if (fc.ac.error == 0) {
afs_vnode_finalise_status_update(vnode, fc.server);
*_server = fc.server;
fc.server = NULL;
} else {
afs_vnode_status_update_failed(&fc, vnode);
*_server = NULL;
}
out:
return afs_end_fs_cursor(&fc, afs_v2net(vnode));
no_server:
spin_lock(&vnode->lock);
vnode->update_cnt--;
ASSERTCMP(vnode->update_cnt, >=, 0);
spin_unlock(&vnode->lock);
*_server = NULL;
goto out;
}
/*
* rename a file
*/
int afs_vnode_rename(struct afs_vnode *orig_dvnode,
struct afs_vnode *new_dvnode,
struct key *key,
const char *orig_name,
const char *new_name)
{
struct afs_fs_cursor fc;
_enter("%s{%x:%u.%u},%s{%u,%u,%u},%x,%s,%s",
orig_dvnode->volume->vlocation->vldb.name,
orig_dvnode->fid.vid,
orig_dvnode->fid.vnode,
orig_dvnode->fid.unique,
new_dvnode->volume->vlocation->vldb.name,
new_dvnode->fid.vid,
new_dvnode->fid.vnode,
new_dvnode->fid.unique,
key_serial(key),
orig_name,
new_name);
/* this op will fetch the status on both the directories we're dealing
* with */
spin_lock(&orig_dvnode->lock);
orig_dvnode->update_cnt++;
spin_unlock(&orig_dvnode->lock);
if (new_dvnode != orig_dvnode) {
spin_lock(&new_dvnode->lock);
new_dvnode->update_cnt++;
spin_unlock(&new_dvnode->lock);
}
afs_init_fs_cursor(&fc, orig_dvnode);
do {
/* pick a server to query */
if (!afs_volume_pick_fileserver(&fc, orig_dvnode))
goto no_server;
fc.ac.error = afs_fs_rename(&fc, key, orig_dvnode, orig_name,
new_dvnode, new_name, false);
} while (afs_iterate_fs_cursor(&fc, orig_dvnode));
/* adjust the flags */
if (fc.ac.error == 0) {
afs_vnode_finalise_status_update(orig_dvnode, fc.server);
if (new_dvnode != orig_dvnode)
afs_vnode_finalise_status_update(new_dvnode, fc.server);
} else {
afs_vnode_status_update_failed(&fc, orig_dvnode);
if (new_dvnode != orig_dvnode)
afs_vnode_status_update_failed(&fc, new_dvnode);
}
out:
return afs_end_fs_cursor(&fc, afs_v2net(orig_dvnode));
no_server:
spin_lock(&orig_dvnode->lock);
orig_dvnode->update_cnt--;
ASSERTCMP(orig_dvnode->update_cnt, >=, 0);
spin_unlock(&orig_dvnode->lock);
if (new_dvnode != orig_dvnode) {
spin_lock(&new_dvnode->lock);
new_dvnode->update_cnt--;
ASSERTCMP(new_dvnode->update_cnt, >=, 0);
spin_unlock(&new_dvnode->lock);
}
goto out;
}
/*
* write to a file
*/
int afs_vnode_store_data(struct afs_writeback *wb, pgoff_t first, pgoff_t last,
unsigned offset, unsigned to)
{
struct afs_fs_cursor fc;
struct afs_vnode *vnode = wb->vnode;
_enter("%s{%x:%u.%u},%x,%lx,%lx,%x,%x",
vnode->volume->vlocation->vldb.name,
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique,
key_serial(wb->key),
first, last, offset, to);
/* this op will fetch the status */
spin_lock(&vnode->lock);
vnode->update_cnt++;
spin_unlock(&vnode->lock);
afs_init_fs_cursor(&fc, vnode);
do {
/* pick a server to query */
if (!afs_volume_pick_fileserver(&fc, vnode))
goto no_server;
fc.ac.error = afs_fs_store_data(&fc, wb, first, last, offset, to,
false);
} while (afs_iterate_fs_cursor(&fc, vnode));
/* adjust the flags */
if (fc.ac.error == 0) {
afs_vnode_finalise_status_update(vnode, fc.server);
} else {
afs_vnode_status_update_failed(&fc, vnode);
}
out:
return afs_end_fs_cursor(&fc, afs_v2net(vnode));
no_server:
spin_lock(&vnode->lock);
vnode->update_cnt--;
ASSERTCMP(vnode->update_cnt, >=, 0);
spin_unlock(&vnode->lock);
goto out;
}
/*
* set the attributes on a file
*/
int afs_vnode_setattr(struct afs_vnode *vnode, struct key *key,
struct iattr *attr)
{
struct afs_fs_cursor fc;
_enter("%s{%x:%u.%u},%x",
vnode->volume->vlocation->vldb.name,
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique,
key_serial(key));
/* this op will fetch the status */
spin_lock(&vnode->lock);
vnode->update_cnt++;
spin_unlock(&vnode->lock);
afs_init_fs_cursor(&fc, vnode);
do {
/* pick a server to query */
if (!afs_volume_pick_fileserver(&fc, vnode))
goto no_server;
fc.ac.error = afs_fs_setattr(&fc, key, vnode, attr, false);
} while (afs_iterate_fs_cursor(&fc, vnode));
/* adjust the flags */
if (fc.ac.error == 0) {
afs_vnode_finalise_status_update(vnode, fc.server);
} else {
afs_vnode_status_update_failed(&fc, vnode);
}
out:
return afs_end_fs_cursor(&fc, afs_v2net(vnode));
no_server:
spin_lock(&vnode->lock);
vnode->update_cnt--;
ASSERTCMP(vnode->update_cnt, >=, 0);
spin_unlock(&vnode->lock);
goto out;
}
/*
* get the status of a volume
*/
int afs_vnode_get_volume_status(struct afs_vnode *vnode, struct key *key,
struct afs_volume_status *vs)
{
struct afs_fs_cursor fc;
_enter("%s{%x:%u.%u},%x,",
vnode->volume->vlocation->vldb.name,
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique,
key_serial(key));
afs_init_fs_cursor(&fc, vnode);
do {
/* pick a server to query */
if (!afs_volume_pick_fileserver(&fc, vnode))
break;
fc.ac.error = afs_fs_get_volume_status(&fc, key, vnode, vs, false);
} while (afs_iterate_fs_cursor(&fc, vnode));
return afs_end_fs_cursor(&fc, afs_v2net(vnode));
}
/*
* get a lock on a file
*/
int afs_vnode_set_lock(struct afs_vnode *vnode, struct key *key,
afs_lock_type_t type)
{
struct afs_fs_cursor fc;
_enter("%s{%x:%u.%u},%x,%u",
vnode->volume->vlocation->vldb.name,
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique,
key_serial(key), type);
afs_init_fs_cursor(&fc, vnode);
do {
/* pick a server to query */
if (!afs_volume_pick_fileserver(&fc, vnode))
break;
fc.ac.error = afs_fs_set_lock(&fc, key, vnode, type, false);
} while (afs_iterate_fs_cursor(&fc, vnode));
return afs_end_fs_cursor(&fc, afs_v2net(vnode));
}
/*
* extend a lock on a file
*/
int afs_vnode_extend_lock(struct afs_vnode *vnode, struct key *key)
{
struct afs_fs_cursor fc;
int ret;
_enter("%s{%x:%u.%u},%x",
vnode->volume->vlocation->vldb.name,
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique,
key_serial(key));
ret = afs_set_fs_cursor(&fc, vnode);
if (ret < 0)
return ret;
fc.ac.error = afs_fs_extend_lock(&fc, key, vnode, false);
return afs_end_fs_cursor(&fc, afs_v2net(vnode));
}
/*
* release a lock on a file
*/
int afs_vnode_release_lock(struct afs_vnode *vnode, struct key *key)
{
struct afs_fs_cursor fc;
int ret;
_enter("%s{%x:%u.%u},%x",
vnode->volume->vlocation->vldb.name,
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique,
key_serial(key));
ret = afs_set_fs_cursor(&fc, vnode);
if (ret < 0)
return ret;
fc.ac.error = afs_fs_release_lock(&fc, key, vnode, false);
return afs_end_fs_cursor(&fc, afs_v2net(vnode));
}
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