linux/fs/afs/addr_list.c

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/* Server address list management
*
* Copyright (C) 2017 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 Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/dns_resolver.h>
#include <linux/inet.h>
#include <keys/rxrpc-type.h>
#include "internal.h"
#include "afs_fs.h"
//#define AFS_MAX_ADDRESSES
// ((unsigned int)((PAGE_SIZE - sizeof(struct afs_addr_list)) /
// sizeof(struct sockaddr_rxrpc)))
#define AFS_MAX_ADDRESSES ((unsigned int)(sizeof(unsigned long) * 8))
/*
* Release an address list.
*/
void afs_put_addrlist(struct afs_addr_list *alist)
{
if (alist && refcount_dec_and_test(&alist->usage))
call_rcu(&alist->rcu, (rcu_callback_t)kfree);
}
/*
* Allocate an address list.
*/
struct afs_addr_list *afs_alloc_addrlist(unsigned int nr,
unsigned short service,
unsigned short port)
{
struct afs_addr_list *alist;
unsigned int i;
_enter("%u,%u,%u", nr, service, port);
treewide: Use struct_size() for kmalloc()-family One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; void *entry[]; }; instance = kmalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL); This patch makes the changes for kmalloc()-family (and kvmalloc()-family) uses. It was done via automatic conversion with manual review for the "CHECKME" non-standard cases noted below, using the following Coccinelle script: // pkey_cache = kmalloc(sizeof *pkey_cache + tprops->pkey_tbl_len * // sizeof *pkey_cache->table, GFP_KERNEL); @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; identifier VAR, ELEMENT; expression COUNT; @@ - alloc(sizeof(*VAR) + COUNT * sizeof(*VAR->ELEMENT), GFP) + alloc(struct_size(VAR, ELEMENT, COUNT), GFP) // mr = kzalloc(sizeof(*mr) + m * sizeof(mr->map[0]), GFP_KERNEL); @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; identifier VAR, ELEMENT; expression COUNT; @@ - alloc(sizeof(*VAR) + COUNT * sizeof(VAR->ELEMENT[0]), GFP) + alloc(struct_size(VAR, ELEMENT, COUNT), GFP) // Same pattern, but can't trivially locate the trailing element name, // or variable name. @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; expression SOMETHING, COUNT, ELEMENT; @@ - alloc(sizeof(SOMETHING) + COUNT * sizeof(ELEMENT), GFP) + alloc(CHECKME_struct_size(&SOMETHING, ELEMENT, COUNT), GFP) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-05-08 20:45:50 +00:00
alist = kzalloc(struct_size(alist, addrs, nr), GFP_KERNEL);
if (!alist)
return NULL;
refcount_set(&alist->usage, 1);
for (i = 0; i < nr; i++) {
struct sockaddr_rxrpc *srx = &alist->addrs[i];
srx->srx_family = AF_RXRPC;
srx->srx_service = service;
srx->transport_type = SOCK_DGRAM;
srx->transport_len = sizeof(srx->transport.sin6);
srx->transport.sin6.sin6_family = AF_INET6;
srx->transport.sin6.sin6_port = htons(port);
}
return alist;
}
/*
* Parse a text string consisting of delimited addresses.
*/
struct afs_addr_list *afs_parse_text_addrs(const char *text, size_t len,
char delim,
unsigned short service,
unsigned short port)
{
struct afs_addr_list *alist;
const char *p, *end = text + len;
unsigned int nr = 0;
_enter("%*.*s,%c", (int)len, (int)len, text, delim);
if (!len)
return ERR_PTR(-EDESTADDRREQ);
if (delim == ':' && (memchr(text, ',', len) || !memchr(text, '.', len)))
delim = ',';
/* Count the addresses */
p = text;
do {
if (!*p)
return ERR_PTR(-EINVAL);
if (*p == delim)
continue;
nr++;
if (*p == '[') {
p++;
if (p == end)
return ERR_PTR(-EINVAL);
p = memchr(p, ']', end - p);
if (!p)
return ERR_PTR(-EINVAL);
p++;
if (p >= end)
break;
}
p = memchr(p, delim, end - p);
if (!p)
break;
p++;
} while (p < end);
_debug("%u/%u addresses", nr, AFS_MAX_ADDRESSES);
if (nr > AFS_MAX_ADDRESSES)
nr = AFS_MAX_ADDRESSES;
alist = afs_alloc_addrlist(nr, service, port);
if (!alist)
return ERR_PTR(-ENOMEM);
/* Extract the addresses */
p = text;
do {
struct sockaddr_rxrpc *srx = &alist->addrs[alist->nr_addrs];
const char *q, *stop;
if (*p == delim) {
p++;
continue;
}
if (*p == '[') {
p++;
q = memchr(p, ']', end - p);
} else {
for (q = p; q < end; q++)
if (*q == '+' || *q == delim)
break;
}
if (in4_pton(p, q - p,
(u8 *)&srx->transport.sin6.sin6_addr.s6_addr32[3],
-1, &stop)) {
srx->transport.sin6.sin6_addr.s6_addr32[0] = 0;
srx->transport.sin6.sin6_addr.s6_addr32[1] = 0;
srx->transport.sin6.sin6_addr.s6_addr32[2] = htonl(0xffff);
} else if (in6_pton(p, q - p,
srx->transport.sin6.sin6_addr.s6_addr,
-1, &stop)) {
/* Nothing to do */
} else {
goto bad_address;
}
if (stop != q)
goto bad_address;
p = q;
if (q < end && *q == ']')
p++;
if (p < end) {
if (*p == '+') {
/* Port number specification "+1234" */
unsigned int xport = 0;
p++;
if (p >= end || !isdigit(*p))
goto bad_address;
do {
xport *= 10;
xport += *p - '0';
if (xport > 65535)
goto bad_address;
p++;
} while (p < end && isdigit(*p));
srx->transport.sin6.sin6_port = htons(xport);
} else if (*p == delim) {
p++;
} else {
goto bad_address;
}
}
alist->nr_addrs++;
} while (p < end && alist->nr_addrs < AFS_MAX_ADDRESSES);
_leave(" = [nr %u]", alist->nr_addrs);
return alist;
bad_address:
kfree(alist);
return ERR_PTR(-EINVAL);
}
/*
* Compare old and new address lists to see if there's been any change.
* - How to do this in better than O(Nlog(N)) time?
* - We don't really want to sort the address list, but would rather take the
* list as we got it so as not to undo record rotation by the DNS server.
*/
#if 0
static int afs_cmp_addr_list(const struct afs_addr_list *a1,
const struct afs_addr_list *a2)
{
}
#endif
/*
* Perform a DNS query for VL servers and build a up an address list.
*/
struct afs_addr_list *afs_dns_query(struct afs_cell *cell, time64_t *_expiry)
{
struct afs_addr_list *alist;
char *vllist = NULL;
int ret;
_enter("%s", cell->name);
ret = dns_query("afsdb", cell->name, cell->name_len,
"", &vllist, _expiry);
if (ret < 0)
return ERR_PTR(ret);
alist = afs_parse_text_addrs(vllist, strlen(vllist), ',',
VL_SERVICE, AFS_VL_PORT);
if (IS_ERR(alist)) {
kfree(vllist);
if (alist != ERR_PTR(-ENOMEM))
pr_err("Failed to parse DNS data\n");
return alist;
}
kfree(vllist);
return alist;
}
afs: Overhaul volume and server record caching and fileserver rotation The current code assumes that volumes and servers are per-cell and are never shared, but this is not enforced, and, indeed, public cells do exist that are aliases of each other. Further, an organisation can, say, set up a public cell and a private cell with overlapping, but not identical, sets of servers. The difference is purely in the database attached to the VL servers. The current code will malfunction if it sees a server in two cells as it assumes global address -> server record mappings and that each server is in just one cell. Further, each server may have multiple addresses - and may have addresses of different families (IPv4 and IPv6, say). To this end, the following structural changes are made: (1) Server record management is overhauled: (a) Server records are made independent of cell. The namespace keeps track of them, volume records have lists of them and each vnode has a server on which its callback interest currently resides. (b) The cell record no longer keeps a list of servers known to be in that cell. (c) The server records are now kept in a flat list because there's no single address to sort on. (d) Server records are now keyed by their UUID within the namespace. (e) The addresses for a server are obtained with the VL.GetAddrsU rather than with VL.GetEntryByName, using the server's UUID as a parameter. (f) Cached server records are garbage collected after a period of non-use and are counted out of existence before purging is allowed to complete. This protects the work functions against rmmod. (g) The servers list is now in /proc/fs/afs/servers. (2) Volume record management is overhauled: (a) An RCU-replaceable server list is introduced. This tracks both servers and their coresponding callback interests. (b) The superblock is now keyed on cell record and numeric volume ID. (c) The volume record is now tied to the superblock which mounts it, and is activated when mounted and deactivated when unmounted. This makes it easier to handle the cache cookie without causing a double-use in fscache. (d) The volume record is loaded from the VLDB using VL.GetEntryByNameU to get the server UUID list. (e) The volume name is updated if it is seen to have changed when the volume is updated (the update is keyed on the volume ID). (3) The vlocation record is got rid of and VLDB records are no longer cached. Sufficient information is stored in the volume record, though an update to a volume record is now no longer shared between related volumes (volumes come in bundles of three: R/W, R/O and backup). and the following procedural changes are made: (1) The fileserver cursor introduced previously is now fleshed out and used to iterate over fileservers and their addresses. (2) Volume status is checked during iteration, and the server list is replaced if a change is detected. (3) Server status is checked during iteration, and the address list is replaced if a change is detected. (4) The abort code is saved into the address list cursor and -ECONNABORTED returned in afs_make_call() if a remote abort happened rather than translating the abort into an error message. This allows actions to be taken depending on the abort code more easily. (a) If a VMOVED abort is seen then this is handled by rechecking the volume and restarting the iteration. (b) If a VBUSY, VRESTARTING or VSALVAGING abort is seen then this is handled by sleeping for a short period and retrying and/or trying other servers that might serve that volume. A message is also displayed once until the condition has cleared. (c) If a VOFFLINE abort is seen, then this is handled as VBUSY for the moment. (d) If a VNOVOL abort is seen, the volume is rechecked in the VLDB to see if it has been deleted; if not, the fileserver is probably indicating that the volume couldn't be attached and needs salvaging. (e) If statfs() sees one of these aborts, it does not sleep, but rather returns an error, so as not to block the umount program. (5) The fileserver iteration functions in vnode.c are now merged into their callers and more heavily macroised around the cursor. vnode.c is removed. (6) Operations on a particular vnode are serialised on that vnode because the server will lock that vnode whilst it operates on it, so a second op sent will just have to wait. (7) Fileservers are probed with FS.GetCapabilities before being used. This is where service upgrade will be done. (8) A callback interest on a fileserver is set up before an FS operation is performed and passed through to afs_make_call() so that it can be set on the vnode if the operation returns a callback. The callback interest is passed through to afs_iget() also so that it can be set there too. In general, record updating is done on an as-needed basis when we try to access servers, volumes or vnodes rather than offloading it to work items and special threads. Notes: (1) Pre AFS-3.4 servers are no longer supported, though this can be added back if necessary (AFS-3.4 was released in 1998). (2) VBUSY is retried forever for the moment at intervals of 1s. (3) /proc/fs/afs/<cell>/servers no longer exists. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-02 15:27:50 +00:00
/*
* Merge an IPv4 entry into a fileserver address list.
*/
void afs_merge_fs_addr4(struct afs_addr_list *alist, __be32 xdr, u16 port)
afs: Overhaul volume and server record caching and fileserver rotation The current code assumes that volumes and servers are per-cell and are never shared, but this is not enforced, and, indeed, public cells do exist that are aliases of each other. Further, an organisation can, say, set up a public cell and a private cell with overlapping, but not identical, sets of servers. The difference is purely in the database attached to the VL servers. The current code will malfunction if it sees a server in two cells as it assumes global address -> server record mappings and that each server is in just one cell. Further, each server may have multiple addresses - and may have addresses of different families (IPv4 and IPv6, say). To this end, the following structural changes are made: (1) Server record management is overhauled: (a) Server records are made independent of cell. The namespace keeps track of them, volume records have lists of them and each vnode has a server on which its callback interest currently resides. (b) The cell record no longer keeps a list of servers known to be in that cell. (c) The server records are now kept in a flat list because there's no single address to sort on. (d) Server records are now keyed by their UUID within the namespace. (e) The addresses for a server are obtained with the VL.GetAddrsU rather than with VL.GetEntryByName, using the server's UUID as a parameter. (f) Cached server records are garbage collected after a period of non-use and are counted out of existence before purging is allowed to complete. This protects the work functions against rmmod. (g) The servers list is now in /proc/fs/afs/servers. (2) Volume record management is overhauled: (a) An RCU-replaceable server list is introduced. This tracks both servers and their coresponding callback interests. (b) The superblock is now keyed on cell record and numeric volume ID. (c) The volume record is now tied to the superblock which mounts it, and is activated when mounted and deactivated when unmounted. This makes it easier to handle the cache cookie without causing a double-use in fscache. (d) The volume record is loaded from the VLDB using VL.GetEntryByNameU to get the server UUID list. (e) The volume name is updated if it is seen to have changed when the volume is updated (the update is keyed on the volume ID). (3) The vlocation record is got rid of and VLDB records are no longer cached. Sufficient information is stored in the volume record, though an update to a volume record is now no longer shared between related volumes (volumes come in bundles of three: R/W, R/O and backup). and the following procedural changes are made: (1) The fileserver cursor introduced previously is now fleshed out and used to iterate over fileservers and their addresses. (2) Volume status is checked during iteration, and the server list is replaced if a change is detected. (3) Server status is checked during iteration, and the address list is replaced if a change is detected. (4) The abort code is saved into the address list cursor and -ECONNABORTED returned in afs_make_call() if a remote abort happened rather than translating the abort into an error message. This allows actions to be taken depending on the abort code more easily. (a) If a VMOVED abort is seen then this is handled by rechecking the volume and restarting the iteration. (b) If a VBUSY, VRESTARTING or VSALVAGING abort is seen then this is handled by sleeping for a short period and retrying and/or trying other servers that might serve that volume. A message is also displayed once until the condition has cleared. (c) If a VOFFLINE abort is seen, then this is handled as VBUSY for the moment. (d) If a VNOVOL abort is seen, the volume is rechecked in the VLDB to see if it has been deleted; if not, the fileserver is probably indicating that the volume couldn't be attached and needs salvaging. (e) If statfs() sees one of these aborts, it does not sleep, but rather returns an error, so as not to block the umount program. (5) The fileserver iteration functions in vnode.c are now merged into their callers and more heavily macroised around the cursor. vnode.c is removed. (6) Operations on a particular vnode are serialised on that vnode because the server will lock that vnode whilst it operates on it, so a second op sent will just have to wait. (7) Fileservers are probed with FS.GetCapabilities before being used. This is where service upgrade will be done. (8) A callback interest on a fileserver is set up before an FS operation is performed and passed through to afs_make_call() so that it can be set on the vnode if the operation returns a callback. The callback interest is passed through to afs_iget() also so that it can be set there too. In general, record updating is done on an as-needed basis when we try to access servers, volumes or vnodes rather than offloading it to work items and special threads. Notes: (1) Pre AFS-3.4 servers are no longer supported, though this can be added back if necessary (AFS-3.4 was released in 1998). (2) VBUSY is retried forever for the moment at intervals of 1s. (3) /proc/fs/afs/<cell>/servers no longer exists. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-02 15:27:50 +00:00
{
struct sockaddr_in6 *a;
__be16 xport = htons(port);
afs: Overhaul volume and server record caching and fileserver rotation The current code assumes that volumes and servers are per-cell and are never shared, but this is not enforced, and, indeed, public cells do exist that are aliases of each other. Further, an organisation can, say, set up a public cell and a private cell with overlapping, but not identical, sets of servers. The difference is purely in the database attached to the VL servers. The current code will malfunction if it sees a server in two cells as it assumes global address -> server record mappings and that each server is in just one cell. Further, each server may have multiple addresses - and may have addresses of different families (IPv4 and IPv6, say). To this end, the following structural changes are made: (1) Server record management is overhauled: (a) Server records are made independent of cell. The namespace keeps track of them, volume records have lists of them and each vnode has a server on which its callback interest currently resides. (b) The cell record no longer keeps a list of servers known to be in that cell. (c) The server records are now kept in a flat list because there's no single address to sort on. (d) Server records are now keyed by their UUID within the namespace. (e) The addresses for a server are obtained with the VL.GetAddrsU rather than with VL.GetEntryByName, using the server's UUID as a parameter. (f) Cached server records are garbage collected after a period of non-use and are counted out of existence before purging is allowed to complete. This protects the work functions against rmmod. (g) The servers list is now in /proc/fs/afs/servers. (2) Volume record management is overhauled: (a) An RCU-replaceable server list is introduced. This tracks both servers and their coresponding callback interests. (b) The superblock is now keyed on cell record and numeric volume ID. (c) The volume record is now tied to the superblock which mounts it, and is activated when mounted and deactivated when unmounted. This makes it easier to handle the cache cookie without causing a double-use in fscache. (d) The volume record is loaded from the VLDB using VL.GetEntryByNameU to get the server UUID list. (e) The volume name is updated if it is seen to have changed when the volume is updated (the update is keyed on the volume ID). (3) The vlocation record is got rid of and VLDB records are no longer cached. Sufficient information is stored in the volume record, though an update to a volume record is now no longer shared between related volumes (volumes come in bundles of three: R/W, R/O and backup). and the following procedural changes are made: (1) The fileserver cursor introduced previously is now fleshed out and used to iterate over fileservers and their addresses. (2) Volume status is checked during iteration, and the server list is replaced if a change is detected. (3) Server status is checked during iteration, and the address list is replaced if a change is detected. (4) The abort code is saved into the address list cursor and -ECONNABORTED returned in afs_make_call() if a remote abort happened rather than translating the abort into an error message. This allows actions to be taken depending on the abort code more easily. (a) If a VMOVED abort is seen then this is handled by rechecking the volume and restarting the iteration. (b) If a VBUSY, VRESTARTING or VSALVAGING abort is seen then this is handled by sleeping for a short period and retrying and/or trying other servers that might serve that volume. A message is also displayed once until the condition has cleared. (c) If a VOFFLINE abort is seen, then this is handled as VBUSY for the moment. (d) If a VNOVOL abort is seen, the volume is rechecked in the VLDB to see if it has been deleted; if not, the fileserver is probably indicating that the volume couldn't be attached and needs salvaging. (e) If statfs() sees one of these aborts, it does not sleep, but rather returns an error, so as not to block the umount program. (5) The fileserver iteration functions in vnode.c are now merged into their callers and more heavily macroised around the cursor. vnode.c is removed. (6) Operations on a particular vnode are serialised on that vnode because the server will lock that vnode whilst it operates on it, so a second op sent will just have to wait. (7) Fileservers are probed with FS.GetCapabilities before being used. This is where service upgrade will be done. (8) A callback interest on a fileserver is set up before an FS operation is performed and passed through to afs_make_call() so that it can be set on the vnode if the operation returns a callback. The callback interest is passed through to afs_iget() also so that it can be set there too. In general, record updating is done on an as-needed basis when we try to access servers, volumes or vnodes rather than offloading it to work items and special threads. Notes: (1) Pre AFS-3.4 servers are no longer supported, though this can be added back if necessary (AFS-3.4 was released in 1998). (2) VBUSY is retried forever for the moment at intervals of 1s. (3) /proc/fs/afs/<cell>/servers no longer exists. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-02 15:27:50 +00:00
int i;
for (i = 0; i < alist->nr_ipv4; i++) {
a = &alist->addrs[i].transport.sin6;
if (xdr == a->sin6_addr.s6_addr32[3] &&
xport == a->sin6_port)
afs: Overhaul volume and server record caching and fileserver rotation The current code assumes that volumes and servers are per-cell and are never shared, but this is not enforced, and, indeed, public cells do exist that are aliases of each other. Further, an organisation can, say, set up a public cell and a private cell with overlapping, but not identical, sets of servers. The difference is purely in the database attached to the VL servers. The current code will malfunction if it sees a server in two cells as it assumes global address -> server record mappings and that each server is in just one cell. Further, each server may have multiple addresses - and may have addresses of different families (IPv4 and IPv6, say). To this end, the following structural changes are made: (1) Server record management is overhauled: (a) Server records are made independent of cell. The namespace keeps track of them, volume records have lists of them and each vnode has a server on which its callback interest currently resides. (b) The cell record no longer keeps a list of servers known to be in that cell. (c) The server records are now kept in a flat list because there's no single address to sort on. (d) Server records are now keyed by their UUID within the namespace. (e) The addresses for a server are obtained with the VL.GetAddrsU rather than with VL.GetEntryByName, using the server's UUID as a parameter. (f) Cached server records are garbage collected after a period of non-use and are counted out of existence before purging is allowed to complete. This protects the work functions against rmmod. (g) The servers list is now in /proc/fs/afs/servers. (2) Volume record management is overhauled: (a) An RCU-replaceable server list is introduced. This tracks both servers and their coresponding callback interests. (b) The superblock is now keyed on cell record and numeric volume ID. (c) The volume record is now tied to the superblock which mounts it, and is activated when mounted and deactivated when unmounted. This makes it easier to handle the cache cookie without causing a double-use in fscache. (d) The volume record is loaded from the VLDB using VL.GetEntryByNameU to get the server UUID list. (e) The volume name is updated if it is seen to have changed when the volume is updated (the update is keyed on the volume ID). (3) The vlocation record is got rid of and VLDB records are no longer cached. Sufficient information is stored in the volume record, though an update to a volume record is now no longer shared between related volumes (volumes come in bundles of three: R/W, R/O and backup). and the following procedural changes are made: (1) The fileserver cursor introduced previously is now fleshed out and used to iterate over fileservers and their addresses. (2) Volume status is checked during iteration, and the server list is replaced if a change is detected. (3) Server status is checked during iteration, and the address list is replaced if a change is detected. (4) The abort code is saved into the address list cursor and -ECONNABORTED returned in afs_make_call() if a remote abort happened rather than translating the abort into an error message. This allows actions to be taken depending on the abort code more easily. (a) If a VMOVED abort is seen then this is handled by rechecking the volume and restarting the iteration. (b) If a VBUSY, VRESTARTING or VSALVAGING abort is seen then this is handled by sleeping for a short period and retrying and/or trying other servers that might serve that volume. A message is also displayed once until the condition has cleared. (c) If a VOFFLINE abort is seen, then this is handled as VBUSY for the moment. (d) If a VNOVOL abort is seen, the volume is rechecked in the VLDB to see if it has been deleted; if not, the fileserver is probably indicating that the volume couldn't be attached and needs salvaging. (e) If statfs() sees one of these aborts, it does not sleep, but rather returns an error, so as not to block the umount program. (5) The fileserver iteration functions in vnode.c are now merged into their callers and more heavily macroised around the cursor. vnode.c is removed. (6) Operations on a particular vnode are serialised on that vnode because the server will lock that vnode whilst it operates on it, so a second op sent will just have to wait. (7) Fileservers are probed with FS.GetCapabilities before being used. This is where service upgrade will be done. (8) A callback interest on a fileserver is set up before an FS operation is performed and passed through to afs_make_call() so that it can be set on the vnode if the operation returns a callback. The callback interest is passed through to afs_iget() also so that it can be set there too. In general, record updating is done on an as-needed basis when we try to access servers, volumes or vnodes rather than offloading it to work items and special threads. Notes: (1) Pre AFS-3.4 servers are no longer supported, though this can be added back if necessary (AFS-3.4 was released in 1998). (2) VBUSY is retried forever for the moment at intervals of 1s. (3) /proc/fs/afs/<cell>/servers no longer exists. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-02 15:27:50 +00:00
return;
if (xdr == a->sin6_addr.s6_addr32[3] &&
afs: Fix checker warnings Fix warnings raised by checker, including: (*) Warnings raised by unequal comparison for the purposes of sorting, where the endianness doesn't matter: fs/afs/addr_list.c:246:21: warning: restricted __be16 degrades to integer fs/afs/addr_list.c:246:30: warning: restricted __be16 degrades to integer fs/afs/addr_list.c:248:21: warning: restricted __be32 degrades to integer fs/afs/addr_list.c:248:49: warning: restricted __be32 degrades to integer fs/afs/addr_list.c:283:21: warning: restricted __be16 degrades to integer fs/afs/addr_list.c:283:30: warning: restricted __be16 degrades to integer (*) afs_set_cb_interest() is not actually used and can be removed. (*) afs_cell_gc_delay() should be provided with a sysctl. (*) afs_cell_destroy() needs to use rcu_access_pointer() to read cell->vl_addrs. (*) afs_init_fs_cursor() should be static. (*) struct afs_vnode::permit_cache needs to be marked __rcu. (*) afs_server_rcu() needs to use rcu_access_pointer(). (*) afs_destroy_server() should use rcu_access_pointer() on server->addresses as the server object is no longer accessible. (*) afs_find_server() casts __be16/__be32 values to int in order to directly compare them for the purpose of finding a match in a list, but is should also annotate the cast with __force to avoid checker warnings. (*) afs_check_permit() accesses vnode->permit_cache outside of the RCU readlock, though it doesn't then access the value; the extraneous access is deleted. False positives: (*) Conditional locking around the code in xdr_decode_AFSFetchStatus. This can be dealt with in a separate patch. fs/afs/fsclient.c:148:9: warning: context imbalance in 'xdr_decode_AFSFetchStatus' - different lock contexts for basic block (*) Incorrect handling of seq-retry lock context balance: fs/afs/inode.c:455:38: warning: context imbalance in 'afs_getattr' - different lock contexts for basic block fs/afs/server.c:52:17: warning: context imbalance in 'afs_find_server' - different lock contexts for basic block fs/afs/server.c:128:17: warning: context imbalance in 'afs_find_server_by_uuid' - different lock contexts for basic block Errors: (*) afs_lookup_cell_rcu() needs to break out of the seq-retry loop, not go round again if it successfully found the workstation cell. (*) Fix UUID decode in afs_deliver_cb_probe_uuid(). (*) afs_cache_permit() has a missing rcu_read_unlock() before one of the jumps to the someone_else_changed_it label. Move the unlock to after the label. (*) afs_vl_get_addrs_u() is using ntohl() rather than htonl() when encoding to XDR. (*) afs_deliver_yfsvl_get_endpoints() is using htonl() rather than ntohl() when decoding from XDR. Signed-off-by: David Howells <dhowells@redhat.com>
2018-04-09 20:12:31 +00:00
(u16 __force)xport < (u16 __force)a->sin6_port)
break;
afs: Fix checker warnings Fix warnings raised by checker, including: (*) Warnings raised by unequal comparison for the purposes of sorting, where the endianness doesn't matter: fs/afs/addr_list.c:246:21: warning: restricted __be16 degrades to integer fs/afs/addr_list.c:246:30: warning: restricted __be16 degrades to integer fs/afs/addr_list.c:248:21: warning: restricted __be32 degrades to integer fs/afs/addr_list.c:248:49: warning: restricted __be32 degrades to integer fs/afs/addr_list.c:283:21: warning: restricted __be16 degrades to integer fs/afs/addr_list.c:283:30: warning: restricted __be16 degrades to integer (*) afs_set_cb_interest() is not actually used and can be removed. (*) afs_cell_gc_delay() should be provided with a sysctl. (*) afs_cell_destroy() needs to use rcu_access_pointer() to read cell->vl_addrs. (*) afs_init_fs_cursor() should be static. (*) struct afs_vnode::permit_cache needs to be marked __rcu. (*) afs_server_rcu() needs to use rcu_access_pointer(). (*) afs_destroy_server() should use rcu_access_pointer() on server->addresses as the server object is no longer accessible. (*) afs_find_server() casts __be16/__be32 values to int in order to directly compare them for the purpose of finding a match in a list, but is should also annotate the cast with __force to avoid checker warnings. (*) afs_check_permit() accesses vnode->permit_cache outside of the RCU readlock, though it doesn't then access the value; the extraneous access is deleted. False positives: (*) Conditional locking around the code in xdr_decode_AFSFetchStatus. This can be dealt with in a separate patch. fs/afs/fsclient.c:148:9: warning: context imbalance in 'xdr_decode_AFSFetchStatus' - different lock contexts for basic block (*) Incorrect handling of seq-retry lock context balance: fs/afs/inode.c:455:38: warning: context imbalance in 'afs_getattr' - different lock contexts for basic block fs/afs/server.c:52:17: warning: context imbalance in 'afs_find_server' - different lock contexts for basic block fs/afs/server.c:128:17: warning: context imbalance in 'afs_find_server_by_uuid' - different lock contexts for basic block Errors: (*) afs_lookup_cell_rcu() needs to break out of the seq-retry loop, not go round again if it successfully found the workstation cell. (*) Fix UUID decode in afs_deliver_cb_probe_uuid(). (*) afs_cache_permit() has a missing rcu_read_unlock() before one of the jumps to the someone_else_changed_it label. Move the unlock to after the label. (*) afs_vl_get_addrs_u() is using ntohl() rather than htonl() when encoding to XDR. (*) afs_deliver_yfsvl_get_endpoints() is using htonl() rather than ntohl() when decoding from XDR. Signed-off-by: David Howells <dhowells@redhat.com>
2018-04-09 20:12:31 +00:00
if ((u32 __force)xdr < (u32 __force)a->sin6_addr.s6_addr32[3])
afs: Overhaul volume and server record caching and fileserver rotation The current code assumes that volumes and servers are per-cell and are never shared, but this is not enforced, and, indeed, public cells do exist that are aliases of each other. Further, an organisation can, say, set up a public cell and a private cell with overlapping, but not identical, sets of servers. The difference is purely in the database attached to the VL servers. The current code will malfunction if it sees a server in two cells as it assumes global address -> server record mappings and that each server is in just one cell. Further, each server may have multiple addresses - and may have addresses of different families (IPv4 and IPv6, say). To this end, the following structural changes are made: (1) Server record management is overhauled: (a) Server records are made independent of cell. The namespace keeps track of them, volume records have lists of them and each vnode has a server on which its callback interest currently resides. (b) The cell record no longer keeps a list of servers known to be in that cell. (c) The server records are now kept in a flat list because there's no single address to sort on. (d) Server records are now keyed by their UUID within the namespace. (e) The addresses for a server are obtained with the VL.GetAddrsU rather than with VL.GetEntryByName, using the server's UUID as a parameter. (f) Cached server records are garbage collected after a period of non-use and are counted out of existence before purging is allowed to complete. This protects the work functions against rmmod. (g) The servers list is now in /proc/fs/afs/servers. (2) Volume record management is overhauled: (a) An RCU-replaceable server list is introduced. This tracks both servers and their coresponding callback interests. (b) The superblock is now keyed on cell record and numeric volume ID. (c) The volume record is now tied to the superblock which mounts it, and is activated when mounted and deactivated when unmounted. This makes it easier to handle the cache cookie without causing a double-use in fscache. (d) The volume record is loaded from the VLDB using VL.GetEntryByNameU to get the server UUID list. (e) The volume name is updated if it is seen to have changed when the volume is updated (the update is keyed on the volume ID). (3) The vlocation record is got rid of and VLDB records are no longer cached. Sufficient information is stored in the volume record, though an update to a volume record is now no longer shared between related volumes (volumes come in bundles of three: R/W, R/O and backup). and the following procedural changes are made: (1) The fileserver cursor introduced previously is now fleshed out and used to iterate over fileservers and their addresses. (2) Volume status is checked during iteration, and the server list is replaced if a change is detected. (3) Server status is checked during iteration, and the address list is replaced if a change is detected. (4) The abort code is saved into the address list cursor and -ECONNABORTED returned in afs_make_call() if a remote abort happened rather than translating the abort into an error message. This allows actions to be taken depending on the abort code more easily. (a) If a VMOVED abort is seen then this is handled by rechecking the volume and restarting the iteration. (b) If a VBUSY, VRESTARTING or VSALVAGING abort is seen then this is handled by sleeping for a short period and retrying and/or trying other servers that might serve that volume. A message is also displayed once until the condition has cleared. (c) If a VOFFLINE abort is seen, then this is handled as VBUSY for the moment. (d) If a VNOVOL abort is seen, the volume is rechecked in the VLDB to see if it has been deleted; if not, the fileserver is probably indicating that the volume couldn't be attached and needs salvaging. (e) If statfs() sees one of these aborts, it does not sleep, but rather returns an error, so as not to block the umount program. (5) The fileserver iteration functions in vnode.c are now merged into their callers and more heavily macroised around the cursor. vnode.c is removed. (6) Operations on a particular vnode are serialised on that vnode because the server will lock that vnode whilst it operates on it, so a second op sent will just have to wait. (7) Fileservers are probed with FS.GetCapabilities before being used. This is where service upgrade will be done. (8) A callback interest on a fileserver is set up before an FS operation is performed and passed through to afs_make_call() so that it can be set on the vnode if the operation returns a callback. The callback interest is passed through to afs_iget() also so that it can be set there too. In general, record updating is done on an as-needed basis when we try to access servers, volumes or vnodes rather than offloading it to work items and special threads. Notes: (1) Pre AFS-3.4 servers are no longer supported, though this can be added back if necessary (AFS-3.4 was released in 1998). (2) VBUSY is retried forever for the moment at intervals of 1s. (3) /proc/fs/afs/<cell>/servers no longer exists. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-02 15:27:50 +00:00
break;
}
if (i < alist->nr_addrs)
memmove(alist->addrs + i + 1,
alist->addrs + i,
sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
a = &alist->addrs[i].transport.sin6;
a->sin6_port = xport;
afs: Overhaul volume and server record caching and fileserver rotation The current code assumes that volumes and servers are per-cell and are never shared, but this is not enforced, and, indeed, public cells do exist that are aliases of each other. Further, an organisation can, say, set up a public cell and a private cell with overlapping, but not identical, sets of servers. The difference is purely in the database attached to the VL servers. The current code will malfunction if it sees a server in two cells as it assumes global address -> server record mappings and that each server is in just one cell. Further, each server may have multiple addresses - and may have addresses of different families (IPv4 and IPv6, say). To this end, the following structural changes are made: (1) Server record management is overhauled: (a) Server records are made independent of cell. The namespace keeps track of them, volume records have lists of them and each vnode has a server on which its callback interest currently resides. (b) The cell record no longer keeps a list of servers known to be in that cell. (c) The server records are now kept in a flat list because there's no single address to sort on. (d) Server records are now keyed by their UUID within the namespace. (e) The addresses for a server are obtained with the VL.GetAddrsU rather than with VL.GetEntryByName, using the server's UUID as a parameter. (f) Cached server records are garbage collected after a period of non-use and are counted out of existence before purging is allowed to complete. This protects the work functions against rmmod. (g) The servers list is now in /proc/fs/afs/servers. (2) Volume record management is overhauled: (a) An RCU-replaceable server list is introduced. This tracks both servers and their coresponding callback interests. (b) The superblock is now keyed on cell record and numeric volume ID. (c) The volume record is now tied to the superblock which mounts it, and is activated when mounted and deactivated when unmounted. This makes it easier to handle the cache cookie without causing a double-use in fscache. (d) The volume record is loaded from the VLDB using VL.GetEntryByNameU to get the server UUID list. (e) The volume name is updated if it is seen to have changed when the volume is updated (the update is keyed on the volume ID). (3) The vlocation record is got rid of and VLDB records are no longer cached. Sufficient information is stored in the volume record, though an update to a volume record is now no longer shared between related volumes (volumes come in bundles of three: R/W, R/O and backup). and the following procedural changes are made: (1) The fileserver cursor introduced previously is now fleshed out and used to iterate over fileservers and their addresses. (2) Volume status is checked during iteration, and the server list is replaced if a change is detected. (3) Server status is checked during iteration, and the address list is replaced if a change is detected. (4) The abort code is saved into the address list cursor and -ECONNABORTED returned in afs_make_call() if a remote abort happened rather than translating the abort into an error message. This allows actions to be taken depending on the abort code more easily. (a) If a VMOVED abort is seen then this is handled by rechecking the volume and restarting the iteration. (b) If a VBUSY, VRESTARTING or VSALVAGING abort is seen then this is handled by sleeping for a short period and retrying and/or trying other servers that might serve that volume. A message is also displayed once until the condition has cleared. (c) If a VOFFLINE abort is seen, then this is handled as VBUSY for the moment. (d) If a VNOVOL abort is seen, the volume is rechecked in the VLDB to see if it has been deleted; if not, the fileserver is probably indicating that the volume couldn't be attached and needs salvaging. (e) If statfs() sees one of these aborts, it does not sleep, but rather returns an error, so as not to block the umount program. (5) The fileserver iteration functions in vnode.c are now merged into their callers and more heavily macroised around the cursor. vnode.c is removed. (6) Operations on a particular vnode are serialised on that vnode because the server will lock that vnode whilst it operates on it, so a second op sent will just have to wait. (7) Fileservers are probed with FS.GetCapabilities before being used. This is where service upgrade will be done. (8) A callback interest on a fileserver is set up before an FS operation is performed and passed through to afs_make_call() so that it can be set on the vnode if the operation returns a callback. The callback interest is passed through to afs_iget() also so that it can be set there too. In general, record updating is done on an as-needed basis when we try to access servers, volumes or vnodes rather than offloading it to work items and special threads. Notes: (1) Pre AFS-3.4 servers are no longer supported, though this can be added back if necessary (AFS-3.4 was released in 1998). (2) VBUSY is retried forever for the moment at intervals of 1s. (3) /proc/fs/afs/<cell>/servers no longer exists. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-02 15:27:50 +00:00
a->sin6_addr.s6_addr32[0] = 0;
a->sin6_addr.s6_addr32[1] = 0;
a->sin6_addr.s6_addr32[2] = htonl(0xffff);
a->sin6_addr.s6_addr32[3] = xdr;
alist->nr_ipv4++;
alist->nr_addrs++;
}
/*
* Merge an IPv6 entry into a fileserver address list.
*/
void afs_merge_fs_addr6(struct afs_addr_list *alist, __be32 *xdr, u16 port)
{
struct sockaddr_in6 *a;
__be16 xport = htons(port);
int i, diff;
for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) {
a = &alist->addrs[i].transport.sin6;
diff = memcmp(xdr, &a->sin6_addr, 16);
if (diff == 0 &&
xport == a->sin6_port)
return;
if (diff == 0 &&
afs: Fix checker warnings Fix warnings raised by checker, including: (*) Warnings raised by unequal comparison for the purposes of sorting, where the endianness doesn't matter: fs/afs/addr_list.c:246:21: warning: restricted __be16 degrades to integer fs/afs/addr_list.c:246:30: warning: restricted __be16 degrades to integer fs/afs/addr_list.c:248:21: warning: restricted __be32 degrades to integer fs/afs/addr_list.c:248:49: warning: restricted __be32 degrades to integer fs/afs/addr_list.c:283:21: warning: restricted __be16 degrades to integer fs/afs/addr_list.c:283:30: warning: restricted __be16 degrades to integer (*) afs_set_cb_interest() is not actually used and can be removed. (*) afs_cell_gc_delay() should be provided with a sysctl. (*) afs_cell_destroy() needs to use rcu_access_pointer() to read cell->vl_addrs. (*) afs_init_fs_cursor() should be static. (*) struct afs_vnode::permit_cache needs to be marked __rcu. (*) afs_server_rcu() needs to use rcu_access_pointer(). (*) afs_destroy_server() should use rcu_access_pointer() on server->addresses as the server object is no longer accessible. (*) afs_find_server() casts __be16/__be32 values to int in order to directly compare them for the purpose of finding a match in a list, but is should also annotate the cast with __force to avoid checker warnings. (*) afs_check_permit() accesses vnode->permit_cache outside of the RCU readlock, though it doesn't then access the value; the extraneous access is deleted. False positives: (*) Conditional locking around the code in xdr_decode_AFSFetchStatus. This can be dealt with in a separate patch. fs/afs/fsclient.c:148:9: warning: context imbalance in 'xdr_decode_AFSFetchStatus' - different lock contexts for basic block (*) Incorrect handling of seq-retry lock context balance: fs/afs/inode.c:455:38: warning: context imbalance in 'afs_getattr' - different lock contexts for basic block fs/afs/server.c:52:17: warning: context imbalance in 'afs_find_server' - different lock contexts for basic block fs/afs/server.c:128:17: warning: context imbalance in 'afs_find_server_by_uuid' - different lock contexts for basic block Errors: (*) afs_lookup_cell_rcu() needs to break out of the seq-retry loop, not go round again if it successfully found the workstation cell. (*) Fix UUID decode in afs_deliver_cb_probe_uuid(). (*) afs_cache_permit() has a missing rcu_read_unlock() before one of the jumps to the someone_else_changed_it label. Move the unlock to after the label. (*) afs_vl_get_addrs_u() is using ntohl() rather than htonl() when encoding to XDR. (*) afs_deliver_yfsvl_get_endpoints() is using htonl() rather than ntohl() when decoding from XDR. Signed-off-by: David Howells <dhowells@redhat.com>
2018-04-09 20:12:31 +00:00
(u16 __force)xport < (u16 __force)a->sin6_port)
break;
if (diff < 0)
break;
}
if (i < alist->nr_addrs)
memmove(alist->addrs + i + 1,
alist->addrs + i,
sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
a = &alist->addrs[i].transport.sin6;
a->sin6_port = xport;
a->sin6_addr.s6_addr32[0] = xdr[0];
a->sin6_addr.s6_addr32[1] = xdr[1];
a->sin6_addr.s6_addr32[2] = xdr[2];
a->sin6_addr.s6_addr32[3] = xdr[3];
alist->nr_addrs++;
}
/*
* Get an address to try.
*/
bool afs_iterate_addresses(struct afs_addr_cursor *ac)
{
_enter("%hu+%hd", ac->start, (short)ac->index);
if (!ac->alist)
return false;
if (ac->begun) {
ac->index++;
if (ac->index == ac->alist->nr_addrs)
ac->index = 0;
if (ac->index == ac->start) {
ac->error = -EDESTADDRREQ;
return false;
}
}
ac->begun = true;
ac->responded = false;
ac->addr = &ac->alist->addrs[ac->index];
return true;
}
/*
* Release an address list cursor.
*/
int afs_end_cursor(struct afs_addr_cursor *ac)
{
struct afs_addr_list *alist;
alist = ac->alist;
if (alist) {
if (ac->responded && ac->index != ac->start)
WRITE_ONCE(alist->index, ac->index);
afs_put_addrlist(alist);
}
ac->addr = NULL;
ac->alist = NULL;
ac->begun = false;
return ac->error;
}
/*
* Set the address cursor for iterating over VL servers.
*/
int afs_set_vl_cursor(struct afs_addr_cursor *ac, struct afs_cell *cell)
{
struct afs_addr_list *alist;
int ret;
if (!rcu_access_pointer(cell->vl_addrs)) {
ret = wait_on_bit(&cell->flags, AFS_CELL_FL_NO_LOOKUP_YET,
TASK_INTERRUPTIBLE);
if (ret < 0)
return ret;
if (!rcu_access_pointer(cell->vl_addrs) &&
ktime_get_real_seconds() < cell->dns_expiry)
return cell->error;
}
read_lock(&cell->vl_addrs_lock);
alist = rcu_dereference_protected(cell->vl_addrs,
lockdep_is_held(&cell->vl_addrs_lock));
if (alist->nr_addrs > 0)
afs_get_addrlist(alist);
else
alist = NULL;
read_unlock(&cell->vl_addrs_lock);
if (!alist)
return -EDESTADDRREQ;
ac->alist = alist;
ac->addr = NULL;
ac->start = READ_ONCE(alist->index);
ac->index = ac->start;
ac->error = 0;
ac->begun = false;
return 0;
}