cregit-Linux how code gets into the kernel

Release 4.10 fs/afs/cell.c

Directory: fs/afs
/* AFS cell and server record 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/module.h>
#include <linux/slab.h>
#include <linux/key.h>
#include <linux/ctype.h>
#include <linux/dns_resolver.h>
#include <linux/sched.h>
#include <keys/rxrpc-type.h>
#include "internal.h"


DECLARE_RWSEM(afs_proc_cells_sem);

LIST_HEAD(afs_proc_cells);

static LIST_HEAD(afs_cells);
static DEFINE_RWLOCK(afs_cells_lock);
static DECLARE_RWSEM(afs_cells_sem); /* add/remove serialisation */
static DECLARE_WAIT_QUEUE_HEAD(afs_cells_freeable_wq);

static struct afs_cell *afs_cell_root;

/*
 * allocate a cell record and fill in its name, VL server address list and
 * allocate an anonymous key
 */

static struct afs_cell *afs_cell_alloc(const char *name, unsigned namelen, char *vllist) { struct afs_cell *cell; struct key *key; char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp, *next; char *dvllist = NULL, *_vllist = NULL; char delimiter = ':'; int ret; _enter("%*.*s,%s", namelen, namelen, name ?: "", vllist); BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */ if (namelen > AFS_MAXCELLNAME) { _leave(" = -ENAMETOOLONG"); return ERR_PTR(-ENAMETOOLONG); } /* allocate and initialise a cell record */ cell = kzalloc(sizeof(struct afs_cell) + namelen + 1, GFP_KERNEL); if (!cell) { _leave(" = -ENOMEM"); return ERR_PTR(-ENOMEM); } memcpy(cell->name, name, namelen); cell->name[namelen] = 0; atomic_set(&cell->usage, 1); INIT_LIST_HEAD(&cell->link); rwlock_init(&cell->servers_lock); INIT_LIST_HEAD(&cell->servers); init_rwsem(&cell->vl_sem); INIT_LIST_HEAD(&cell->vl_list); spin_lock_init(&cell->vl_lock); /* if the ip address is invalid, try dns query */ if (!vllist || strlen(vllist) < 7) { ret = dns_query("afsdb", name, namelen, "ipv4", &dvllist, NULL); if (ret < 0) { if (ret == -ENODATA || ret == -EAGAIN || ret == -ENOKEY) /* translate these errors into something * userspace might understand */ ret = -EDESTADDRREQ; _leave(" = %d", ret); return ERR_PTR(ret); } _vllist = dvllist; /* change the delimiter for user-space reply */ delimiter = ','; } else { _vllist = vllist; } /* fill in the VL server list from the rest of the string */ do { unsigned a, b, c, d; next = strchr(_vllist, delimiter); if (next) *next++ = 0; if (sscanf(_vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4) goto bad_address; if (a > 255 || b > 255 || c > 255 || d > 255) goto bad_address; cell->vl_addrs[cell->vl_naddrs++].s_addr = htonl((a << 24) | (b << 16) | (c << 8) | d); } while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS && (_vllist = next)); /* create a key to represent an anonymous user */ memcpy(keyname, "afs@", 4); dp = keyname + 4; cp = cell->name; do { *dp++ = toupper(*cp); } while (*cp++); key = rxrpc_get_null_key(keyname); if (IS_ERR(key)) { _debug("no key"); ret = PTR_ERR(key); goto error; } cell->anonymous_key = key; _debug("anon key %p{%x}", cell->anonymous_key, key_serial(cell->anonymous_key)); _leave(" = %p", cell); return cell; bad_address: printk(KERN_ERR "kAFS: bad VL server IP address\n"); ret = -EINVAL; error: key_put(cell->anonymous_key); kfree(dvllist); kfree(cell); _leave(" = %d", ret); return ERR_PTR(ret); }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells45576.09%555.56%
wang leiwang lei13622.74%333.33%
andrew mortonandrew morton71.17%111.11%
Total598100.00%9100.00%

/* * afs_cell_crate() - create a cell record * @name: is the name of the cell. * @namsesz: is the strlen of the cell name. * @vllist: is a colon separated list of IP addresses in "a.b.c.d" format. * @retref: is T to return the cell reference when the cell exists. */
struct afs_cell *afs_cell_create(const char *name, unsigned namesz, char *vllist, bool retref) { struct afs_cell *cell; int ret; _enter("%*.*s,%s", namesz, namesz, name ?: "", vllist); down_write(&afs_cells_sem); read_lock(&afs_cells_lock); list_for_each_entry(cell, &afs_cells, link) { if (strncasecmp(cell->name, name, namesz) == 0) goto duplicate_name; } read_unlock(&afs_cells_lock); cell = afs_cell_alloc(name, namesz, vllist); if (IS_ERR(cell)) { _leave(" = %ld", PTR_ERR(cell)); up_write(&afs_cells_sem); return cell; } /* add a proc directory for this cell */ ret = afs_proc_cell_setup(cell); if (ret < 0) goto error; #ifdef CONFIG_AFS_FSCACHE /* put it up for caching (this never returns an error) */ cell->cache = fscache_acquire_cookie(afs_cache_netfs.primary_index, &afs_cell_cache_index_def, cell, true); #endif /* add to the cell lists */ write_lock(&afs_cells_lock); list_add_tail(&cell->link, &afs_cells); write_unlock(&afs_cells_lock); down_write(&afs_proc_cells_sem); list_add_tail(&cell->proc_link, &afs_proc_cells); up_write(&afs_proc_cells_sem); up_write(&afs_cells_sem); _leave(" = %p", cell); return cell; error: up_write(&afs_cells_sem); key_put(cell->anonymous_key); kfree(cell); _leave(" = %d", ret); return ERR_PTR(ret); duplicate_name: if (retref && !IS_ERR(cell)) afs_get_cell(cell); read_unlock(&afs_cells_lock); up_write(&afs_cells_sem); if (retref) { _leave(" = %p", cell); return cell; } _leave(" = -EEXIST"); return ERR_PTR(-EEXIST); }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells19259.08%660.00%
sven schnellesven schnelle7021.54%220.00%
wang leiwang lei5516.92%110.00%
andrew mortonandrew morton82.46%110.00%
Total325100.00%10100.00%

/* * set the root cell information * - can be called with a module parameter string * - can be called from a write to /proc/fs/afs/rootcell */
int afs_cell_init(char *rootcell) { struct afs_cell *old_root, *new_root; char *cp; _enter(""); if (!rootcell) { /* module is loaded with no parameters, or built statically. * - in the future we might initialize cell DB here. */ _leave(" = 0 [no root]"); return 0; } cp = strchr(rootcell, ':'); if (!cp) _debug("kAFS: no VL server IP addresses specified"); else *cp++ = 0; /* allocate a cell record for the root cell */ new_root = afs_cell_create(rootcell, strlen(rootcell), cp, false); if (IS_ERR(new_root)) { _leave(" = %ld", PTR_ERR(new_root)); return PTR_ERR(new_root); } /* install the new cell */ write_lock(&afs_cells_lock); old_root = afs_cell_root; afs_cell_root = new_root; write_unlock(&afs_cells_lock); afs_put_cell(old_root); _leave(" = 0"); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells8357.64%240.00%
andrew mortonandrew morton5034.72%120.00%
wang leiwang lei117.64%240.00%
Total144100.00%5100.00%

/* * lookup a cell record */
struct afs_cell *afs_cell_lookup(const char *name, unsigned namesz, bool dns_cell) { struct afs_cell *cell; _enter("\"%*.*s\",", namesz, namesz, name ?: ""); down_read(&afs_cells_sem); read_lock(&afs_cells_lock); if (name) { /* if the cell was named, look for it in the cell record list */ list_for_each_entry(cell, &afs_cells, link) { if (strncmp(cell->name, name, namesz) == 0) { afs_get_cell(cell); goto found; } } cell = ERR_PTR(-ENOENT); if (dns_cell) goto create_cell; found: ; } else { cell = afs_cell_root; if (!cell) { /* this should not happen unless user tries to mount * when root cell is not set. Return an impossibly * bizarre errno to alert the user. Things like * ENOENT might be "more appropriate" but they happen * for other reasons. */ cell = ERR_PTR(-EDESTADDRREQ); } else { afs_get_cell(cell); } } read_unlock(&afs_cells_lock); up_read(&afs_cells_sem); _leave(" = %p", cell); return cell; create_cell: read_unlock(&afs_cells_lock); up_read(&afs_cells_sem); cell = afs_cell_create(name, namesz, NULL, true); _leave(" = %p", cell); return cell; }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells12462.31%350.00%
wang leiwang lei4723.62%116.67%
andrew mortonandrew morton2713.57%116.67%
lucas de marchilucas de marchi10.50%116.67%
Total199100.00%6100.00%

#if 0 /* * try and get a cell record */ struct afs_cell *afs_get_cell_maybe(struct afs_cell *cell) { write_lock(&afs_cells_lock); if (cell && !list_empty(&cell->link)) afs_get_cell(cell); else cell = NULL; write_unlock(&afs_cells_lock); return cell; } #endif /* 0 */ /* * destroy a cell record */
void afs_put_cell(struct afs_cell *cell) { if (!cell) return; _enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name); ASSERTCMP(atomic_read(&cell->usage), >, 0); /* to prevent a race, the decrement and the dequeue must be effectively * atomic */ write_lock(&afs_cells_lock); if (likely(!atomic_dec_and_test(&cell->usage))) { write_unlock(&afs_cells_lock); _leave(""); return; } ASSERT(list_empty(&cell->servers)); ASSERT(list_empty(&cell->vl_list)); write_unlock(&afs_cells_lock); wake_up(&afs_cells_freeable_wq); _leave(" [unused]"); }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells11391.13%375.00%
andrew mortonandrew morton118.87%125.00%
Total124100.00%4100.00%

/* * destroy a cell record * - must be called with the afs_cells_sem write-locked * - cell->link should have been broken by the caller */
static void afs_cell_destroy(struct afs_cell *cell) { _enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name); ASSERTCMP(atomic_read(&cell->usage), >=, 0); ASSERT(list_empty(&cell->link)); /* wait for everyone to stop using the cell */ if (atomic_read(&cell->usage) > 0) { DECLARE_WAITQUEUE(myself, current); _debug("wait for cell %s", cell->name); set_current_state(TASK_UNINTERRUPTIBLE); add_wait_queue(&afs_cells_freeable_wq, &myself); while (atomic_read(&cell->usage) > 0) { schedule(); set_current_state(TASK_UNINTERRUPTIBLE); } remove_wait_queue(&afs_cells_freeable_wq, &myself); set_current_state(TASK_RUNNING); } _debug("cell dead"); ASSERTCMP(atomic_read(&cell->usage), ==, 0); ASSERT(list_empty(&cell->servers)); ASSERT(list_empty(&cell->vl_list)); afs_proc_cell_remove(cell); down_write(&afs_proc_cells_sem); list_del_init(&cell->proc_link); up_write(&afs_proc_cells_sem); #ifdef CONFIG_AFS_FSCACHE fscache_relinquish_cookie(cell->cache, 0); #endif key_put(cell->anonymous_key); kfree(cell); _leave(" [destroyed]"); }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells22394.89%583.33%
andrew mortonandrew morton125.11%116.67%
Total235100.00%6100.00%

/* * purge in-memory cell database on module unload or afs_init() failure * - the timeout daemon is stopped before calling this */
void afs_cell_purge(void) { struct afs_cell *cell; _enter(""); afs_put_cell(afs_cell_root); down_write(&afs_cells_sem); while (!list_empty(&afs_cells)) { cell = NULL; /* remove the next cell from the front of the list */ write_lock(&afs_cells_lock); if (!list_empty(&afs_cells)) { cell = list_entry(afs_cells.next, struct afs_cell, link); list_del_init(&cell->link); } write_unlock(&afs_cells_lock); if (cell) { _debug("PURGING CELL %s (%d)", cell->name, atomic_read(&cell->usage)); /* now the cell should be left with no references */ afs_cell_destroy(cell); } } up_write(&afs_cells_sem); _leave(""); }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells12596.90%266.67%
andrew mortonandrew morton43.10%133.33%
Total129100.00%3100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells137474.88%842.11%
wang leiwang lei25313.79%315.79%
andrew mortonandrew morton1216.59%15.26%
sven schnellesven schnelle703.81%210.53%
adrian bunkadrian bunk70.38%15.26%
thomas gleixnerthomas gleixner40.22%15.26%
alexey dobriyanalexey dobriyan30.16%15.26%
robert p. j. dayrobert p. j. day20.11%15.26%
lucas de marchilucas de marchi10.05%15.26%
Total1835100.00%19100.00%
Directory: fs/afs
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