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Subject[RFC][PATCH 7/7] v9fs: debug and support routines (2.0-rc7)
This is part [7/7] of the v9fs-2.0-rc7 patch against Linux 2.6.

This part of the patch contains debug and other misc routines.

Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>


----------

debug.h | 69 ++++++++++++++++++
error.c | 92 ++++++++++++++++++++++++
error.h | 176 +++++++++++++++++++++++++++++++++++++++++++++++
fid.c | 232 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
fid.h | 55 ++++++++++++++
idpool.c | 150 ++++++++++++++++++++++++++++++++++++++++
idpool.h | 40 ++++++++++
7 files changed, 814 insertions(+)

----------

Index: fs/9p/debug.h
===================================================================
--- /dev/null (tree:3c5e9440c6a37c3355b50608836a23c8fa4eec99)
+++ 7d6ca5270f0ecf9306a944a3d39897a97dc9f67f/fs/9p/debug.h (mode:100644)
@@ -0,0 +1,69 @@
+/*
+ * linux/fs/9p/debug.h - V9FS Debug Definitions
+ *
+ * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#define DEBUG_ERROR (1<<0)
+#define DEBUG_CURRENT (1<<1)
+#define DEBUG_9P (1<<2)
+#define DEBUG_VFS (1<<3)
+#define DEBUG_CONV (1<<4)
+#define DEBUG_MUX (1<<5)
+#define DEBUG_TRANS (1<<6)
+#define DEBUG_SLABS (1<<7)
+
+#define DEBUG_DUMP_PKT 0
+#define DEBUG_LEAKS
+
+extern int v9fs_debug_level;
+
+#define dprintk(level, format, arg...) \
+do { \
+ if((v9fs_debug_level & level)==level) \
+ printk(KERN_NOTICE "-- %s (%d): " \
+ format , __FUNCTION__, current->pid , ## arg); \
+} while(0)
+
+#define eprintk(level, format, arg...) \
+do { \
+ printk(level "v9fs: %s (%d): " \
+ format , __FUNCTION__, current->pid, ## arg); \
+} while(0)
+
+#if DEBUG_DUMP_PKT
+static inline void dump_data(const unsigned char *data, unsigned int datalen)
+{
+ int i, j;
+ int len = datalen;
+
+ printk(KERN_DEBUG "data ");
+ for (i = 0; i < len; i += 4) {
+ for (j = 0; (j < 4) && (i + j < len); j++)
+ printk(KERN_DEBUG "%02x", data[i + j]);
+ printk(KERN_DEBUG " ");
+ }
+ printk(KERN_DEBUG "\n");
+}
+#else /* DEBUG_DUMP_PKT */
+static inline void dump_data(const unsigned char *data, unsigned int datalen)
+{
+
+}
+#endif /* DEBUG_DUMP_PKT */
Index: fs/9p/error.h
===================================================================
--- /dev/null (tree:3c5e9440c6a37c3355b50608836a23c8fa4eec99)
+++ 7d6ca5270f0ecf9306a944a3d39897a97dc9f67f/fs/9p/error.h (mode:100644)
@@ -0,0 +1,176 @@
+/*
+ * linux/fs/9p/error.h
+ *
+ * Huge Nasty Error Table
+ *
+ * Plan 9 uses error strings, Unix uses error numbers. This table tries to
+ * match UNIX strings and Plan 9 strings to unix error numbers. It is used
+ * to preload the dynamic error table which can also track user-specific error
+ * strings.
+ *
+ * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/errno.h>
+
+struct errormap {
+ char *name;
+ int val;
+
+ struct hlist_node list;
+};
+
+#define ERRHASHSZ 32
+static struct hlist_head hash_errmap[ERRHASHSZ];
+
+/* FixMe - reduce to a reasonable size */
+static struct errormap errmap[] = {
+ {"Operation not permitted", 1},
+ {"wstat prohibited", 1},
+ {"No such file or directory", 2},
+ {"file not found", 2},
+ {"Interrupted system call", 4},
+ {"Input/output error", 5},
+ {"No such device or address", 6},
+ {"Argument list too long", 7},
+ {"Bad file descriptor", 9},
+ {"Resource temporarily unavailable", 11},
+ {"Cannot allocate memory", 12},
+ {"Permission denied", 13},
+ {"Bad address", 14},
+ {"Block device required", 15},
+ {"Device or resource busy", 16},
+ {"File exists", 17},
+ {"Invalid cross-device link", 18},
+ {"No such device", 19},
+ {"Not a directory", 20},
+ {"Is a directory", 21},
+ {"Invalid argument", 22},
+ {"Too many open files in system", 23},
+ {"Too many open files", 24},
+ {"Text file busy", 26},
+ {"File too large", 27},
+ {"No space left on device", 28},
+ {"Illegal seek", 29},
+ {"Read-only file system", 30},
+ {"Too many links", 31},
+ {"Broken pipe", 32},
+ {"Numerical argument out of domain", 33},
+ {"Numerical result out of range", 34},
+ {"Resource deadlock avoided", 35},
+ {"File name too long", 36},
+ {"No locks available", 37},
+ {"Function not implemented", 38},
+ {"Directory not empty", 39},
+ {"Too many levels of symbolic links", 40},
+ {"Unknown error 41", 41},
+ {"No message of desired type", 42},
+ {"Identifier removed", 43},
+ {"File locking deadlock error", 58},
+ {"No data available", 61},
+ {"Machine is not on the network", 64},
+ {"Package not installed", 65},
+ {"Object is remote", 66},
+ {"Link has been severed", 67},
+ {"Communication error on send", 70},
+ {"Protocol error", 71},
+ {"Bad message", 74},
+ {"File descriptor in bad state", 77},
+ {"Streams pipe error", 86},
+ {"Too many users", 87},
+ {"Socket operation on non-socket", 88},
+ {"Message too long", 90},
+ {"Protocol not available", 92},
+ {"Protocol not supported", 93},
+ {"Socket type not supported", 94},
+ {"Operation not supported", 95},
+ {"Protocol family not supported", 96},
+ {"Network is down", 100},
+ {"Network is unreachable", 101},
+ {"Network dropped connection on reset", 102},
+ {"Software caused connection abort", 103},
+ {"Connection reset by peer", 104},
+ {"No buffer space available", 105},
+ {"Transport endpoint is already connected", 106},
+ {"Transport endpoint is not connected", 107},
+ {"Cannot send after transport endpoint shutdown", 108},
+ {"Connection timed out", 110},
+ {"Connection refused", 111},
+ {"Host is down", 112},
+ {"No route to host", 113},
+ {"Operation already in progress", 114},
+ {"Operation now in progress", 115},
+ {"Is a named type file", 120},
+ {"Remote I/O error", 121},
+ {"Disk quota exceeded", 122},
+ {"Operation canceled", 125},
+ {"Unknown error 126", 126},
+ {"Unknown error 127", 127},
+/* errors from fossil, vacfs, and u9fs */
+ {"fid unknown or out of range", EBADF},
+ {"permission denied", EACCES},
+ {"file does not exist", ENOENT},
+ {"authentication failed", ECONNREFUSED},
+ {"bad offset in directory read", ESPIPE},
+ {"bad use of fid", EBADF},
+ {"wstat can't convert between files and directories", EPERM},
+ {"directory is not empty", ENOTEMPTY},
+ {"file exists", EEXIST},
+ {"file already exists", EEXIST},
+ {"file or directory already exists", EEXIST},
+ {"fid already in use", EBADF},
+ {"file in use", ETXTBSY},
+ {"i/o error", EIO},
+ {"file already open for I/O", ETXTBSY},
+ {"illegal mode", EINVAL},
+ {"illegal name", ENAMETOOLONG},
+ {"not a directory", ENOTDIR},
+ {"not a member of proposed group", EINVAL},
+ {"not owner", EACCES},
+ {"only owner can change group in wstat", EACCES},
+ {"read only file system", EROFS},
+ {"no access to special file", EPERM},
+ {"i/o count too large", EIO},
+ {"unknown group", EINVAL},
+ {"unknown user", EINVAL},
+ {"bogus wstat buffer", EPROTO},
+ {"exclusive use file already open", EAGAIN},
+ {"corrupted directory entry", EIO},
+ {"corrupted file entry", EIO},
+ {"corrupted block label", EIO},
+ {"corrupted meta data", EIO},
+ {"illegal offset", EINVAL},
+ {"illegal path element", ENOENT},
+ {"root of file system is corrupted", EIO},
+ {"corrupted super block", EIO},
+ {"protocol botch", EPROTO},
+ {"file system is full", ENOSPC},
+ {"file is in use", EAGAIN},
+ {"directory entry is not allocated", ENOENT},
+ {"file is read only", EROFS},
+ {"file has been removed", EIDRM},
+ {"only support truncation to zero length", EPERM},
+ {"cannot remove root", EPERM},
+ {"file too big", EFBIG},
+ {"venti i/o error", EIO},
+ /* these are not errors */
+ {"u9fs rhostsauth: no authentication required", 0},
+ {"u9fs authnone: no authentication required", 0},
+ {NULL, -1}
+};
Index: fs/9p/error.c
===================================================================
--- /dev/null (tree:3c5e9440c6a37c3355b50608836a23c8fa4eec99)
+++ 7d6ca5270f0ecf9306a944a3d39897a97dc9f67f/fs/9p/error.c (mode:100644)
@@ -0,0 +1,92 @@
+/*
+ * linux/fs/9p/error.c
+ *
+ * Error string handling
+ *
+ * Plan 9 uses error strings, Unix uses error numbers. These functions
+ * try to help manage that and provide for dynamically adding error
+ * mappings.
+ *
+ * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+
+#include <linux/list.h>
+#include <linux/jhash.h>
+
+#include "debug.h"
+#include "error.h"
+
+/**
+ * v9fs_error_init - preload
+ * @errstr: error string
+ *
+ */
+
+int v9fs_error_init(void)
+{
+ struct errormap *c;
+ int bucket;
+
+ /* initialize hash table */
+ for (bucket = 0; bucket < ERRHASHSZ; bucket++)
+ INIT_HLIST_HEAD(&hash_errmap[bucket]);
+
+ /* load initial error map into hash table */
+ for (c = errmap; c->name != NULL; c++) {
+ bucket = jhash(c->name, strlen(c->name), 0) % ERRHASHSZ;
+ INIT_HLIST_NODE(&c->list);
+ hlist_add_head(&c->list, &hash_errmap[bucket]);
+ }
+
+ return 1;
+}
+
+/**
+ * errstr2errno - convert error string to error number
+ * @errstr: error string
+ *
+ */
+
+int v9fs_errstr2errno(char *errstr)
+{
+ int errno = 0;
+ struct hlist_node *p = NULL;
+ struct errormap *c = NULL;
+ int bucket = jhash(errstr, strlen(errstr), 0) % ERRHASHSZ;
+
+ hlist_for_each(p, &hash_errmap[bucket]) {
+ c = hlist_entry(p, struct errormap, list);
+ if (!strcmp(c->name, errstr)) {
+ errno = c->val;
+ break;
+ }
+ }
+
+ if (errno == 0) {
+ /* TODO: if error isn't found, add it dynamically */
+ printk(KERN_ERR "%s: errstr :%s: not found\n", __FUNCTION__,
+ errstr);
+ errno = 1;
+ }
+
+ return -errno;
+}
Index: fs/9p/fid.h
===================================================================
--- /dev/null (tree:3c5e9440c6a37c3355b50608836a23c8fa4eec99)
+++ 7d6ca5270f0ecf9306a944a3d39897a97dc9f67f/fs/9p/fid.h (mode:100644)
@@ -0,0 +1,55 @@
+/*
+ * V9FS FID Management
+ *
+ * Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/list.h>
+
+#define FID_OP 0
+#define FID_WALK 1
+
+struct v9fs_fid {
+ struct list_head list; /* list of fids associated with a dentry */
+ struct list_head active; /* XXX - debug */
+
+ u32 fid;
+ unsigned char fidopen; /* set when fid is opened */
+ unsigned char fidcreate; /* set when fid was just created */
+ unsigned char fidclunked;/* set when fid has already been clunked */
+
+ struct v9fs_qid qid;
+ u32 iounit;
+
+ /* readdir stuff */
+ int rdir_fpos;
+ loff_t rdir_pos;
+ struct v9fs_fcall *rdir_fcall;
+
+ /* management stuff */
+ pid_t pid; /* thread associated with this fid */
+ uid_t uid; /* user associated with this fid */
+
+ /* private data */
+ struct file *filp; /* backpointer to File struct for open files */
+ struct v9fs_session_info *v9ses; /* session info for this FID */
+};
+
+struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry, int type);
+void v9fs_fid_destroy(struct v9fs_fid *fid);
+struct v9fs_fid *v9fs_fid_create(struct dentry *);
Index: fs/9p/fid.c
===================================================================
--- /dev/null (tree:3c5e9440c6a37c3355b50608836a23c8fa4eec99)
+++ 7d6ca5270f0ecf9306a944a3d39897a97dc9f67f/fs/9p/fid.c (mode:100644)
@@ -0,0 +1,232 @@
+/*
+ * V9FS FID Management
+ *
+ * Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+
+#include "debug.h"
+#include "idpool.h"
+#include "v9fs.h"
+#include "9p.h"
+#include "v9fs_vfs.h"
+#include "transport.h"
+#include "mux.h"
+#include "conv.h"
+#include "fid.h"
+
+/**
+ * v9fs_fid_insert - add a fid to a dentry
+ * @fid: fid to add
+ * @dentry: dentry that it is being added to
+ *
+ */
+
+static int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry)
+{
+ struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
+ dprintk(DEBUG_9P, "fid %d (%p) dentry %s (%p)\n", fid->fid, fid,
+ dentry->d_iname, dentry);
+ if (dentry->d_fsdata == NULL) {
+ dentry->d_fsdata =
+ kmalloc(sizeof(struct list_head), GFP_KERNEL);
+ if (dentry->d_fsdata == NULL) {
+ dprintk(DEBUG_ERROR, "Out of memory\n");
+ return -ENOMEM;
+ }
+ fid_list = (struct list_head *)dentry->d_fsdata;
+ INIT_LIST_HEAD(fid_list); /* Initialize list head */
+ }
+
+ fid->uid = current->uid;
+ fid->pid = current->pid;
+ list_add(&fid->list, fid_list);
+ return 0;
+}
+
+/**
+ * v9fs_fid_create - allocate a FID structure
+ * @dentry - dentry to link newly created fid to
+ *
+ */
+
+struct v9fs_fid *v9fs_fid_create(struct dentry *dentry)
+{
+ struct v9fs_fid *new;
+
+ new = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
+ if (new == NULL) {
+ dprintk(DEBUG_ERROR, "Out of Memory\n");
+ return ERR_PTR(-ENOMEM);
+ }
+
+ new->fid = -1;
+ new->fidopen = 0;
+ new->fidcreate = 0;
+ new->fidclunked = 0;
+ new->iounit = 0;
+
+ if (v9fs_fid_insert(new, dentry) == 0)
+ return new;
+ else {
+ dprintk(DEBUG_ERROR, "Problems inserting to dentry\n");
+ kfree(new);
+ return NULL;
+ }
+}
+
+/**
+ * v9fs_fid_destroy - deallocate a FID structure
+ * @fid: fid to destroy
+ *
+ */
+
+void v9fs_fid_destroy(struct v9fs_fid *fid)
+{
+ list_del(&fid->list);
+ kfree(fid);
+}
+
+/**
+ * v9fs_fid_lookup - retrieve the right fid from a particular dentry
+ * @dentry: dentry to look for fid in
+ * @type: intent of lookup (operation or traversal)
+ *
+ * search list of fids associated with a dentry for a fid with a matching
+ * thread id or uid. If that fails, look up the dentry's parents to see if you
+ * can find a matching fid.
+ *
+ */
+
+struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry, int type)
+{
+ struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
+ struct v9fs_fid *current_fid = NULL;
+ struct list_head *p, *temp;
+ struct v9fs_fid *return_fid = NULL;
+ int found_parent = 0;
+ int found_user = 0;
+
+ dprintk(DEBUG_9P, " dentry: %s (%p) type %d\n", dentry->d_iname, dentry,
+ type);
+
+ if (fid_list && !list_empty(fid_list)) {
+ list_for_each_safe(p, temp, fid_list) {
+ current_fid = list_entry(p, struct v9fs_fid, list);
+ if (current_fid->uid == current->uid) {
+ if (return_fid == NULL) {
+ if ((type == FID_OP)
+ || (!current_fid->fidopen)) {
+ return_fid = current_fid;
+ found_user = 1;
+ }
+ }
+ }
+ if (current_fid->pid == current->real_parent->pid) {
+ if ((return_fid == NULL) || (found_parent)
+ || (found_user)) {
+ if ((type == FID_OP)
+ || (!current_fid->fidopen)) {
+ return_fid = current_fid;
+ found_parent = 1;
+ found_user = 0;
+ }
+ }
+ }
+ if (current_fid->pid == current->pid) {
+ if ((type == FID_OP) || (!current_fid->fidopen)) {
+ return_fid = current_fid;
+ found_parent = 0;
+ found_user = 0;
+ }
+ }
+ }
+ }
+
+ /* we are at the root but didn't match */
+ if((!return_fid) && (dentry->d_parent == dentry)) {
+ /* TODO: clone attach with new uid */
+ return_fid = current_fid;
+ }
+
+ if (!return_fid) {
+ struct dentry *par = current->fs->pwd->d_parent;
+ int count = 1;
+ while (par != NULL) {
+ if (par == dentry)
+ break;
+ count++;
+ if (par == par->d_parent) {
+ dprintk(DEBUG_ERROR,
+ "got to root without finding dentry\n");
+ break;
+ }
+ par = par->d_parent;
+ }
+
+/* XXX - there may be some duplication we can get rid of */
+ if (par == dentry) {
+ /* we need to fid_lookup the starting point */
+ int fidnum = -1;
+ int oldfid = -1;
+ int result = -1;
+ struct v9fs_session_info *v9ses =
+ v9fs_inode2v9ses(current->fs->pwd->d_inode);
+
+ current_fid =
+ v9fs_fid_lookup(current->fs->pwd, FID_WALK);
+ if (current_fid == NULL) {
+ dprintk(DEBUG_ERROR,
+ "process cwd doesn't have a fid\n");
+ return return_fid;
+ }
+ oldfid = current_fid->fid;
+ par = current->fs->pwd;
+ /* TODO: take advantage of multiwalk */
+ fidnum = v9fs_get_idpool(&v9ses->fidpool);
+ while (par != dentry) {
+ result =
+ v9fs_t_walk(v9ses, oldfid, fidnum, "..",
+ NULL);
+ if (result < 0) {
+ dprintk(DEBUG_ERROR,
+ "problem walking to parent\n");
+
+ break;
+ }
+ oldfid = fidnum;
+ if (par == par->d_parent) {
+ dprintk(DEBUG_ERROR,
+ "can't find dentry\n");
+ break;
+ }
+ par = par->d_parent;
+ }
+ if (par == dentry) {
+ return_fid = v9fs_fid_create(dentry);
+ return_fid->fid = fidnum;
+ }
+ }
+ }
+
+ return return_fid;
+}
Index: fs/9p/idpool.h
===================================================================
--- /dev/null (tree:3c5e9440c6a37c3355b50608836a23c8fa4eec99)
+++ 7d6ca5270f0ecf9306a944a3d39897a97dc9f67f/fs/9p/idpool.h (mode:100644)
@@ -0,0 +1,40 @@
+/*
+ * linux/fs/9p/idpool.h
+ *
+ * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+/*
+ * This is for getting unique IDs.
+ * 0 means free, non-zero means used.
+ *
+ */
+
+struct idpool {
+ struct semaphore sem;
+ int maxalloc;
+ int numalloc;
+ int lastfree;
+ unsigned long *idlist;
+};
+
+int v9fs_alloc_idpool(struct idpool *, int);
+void v9fs_free_idpool(struct idpool *);
+int v9fs_get_idpool(struct idpool *i);
+void v9fs_put_idpool(int which, struct idpool *i);
Index: fs/9p/idpool.c
===================================================================
--- /dev/null (tree:3c5e9440c6a37c3355b50608836a23c8fa4eec99)
+++ 7d6ca5270f0ecf9306a944a3d39897a97dc9f67f/fs/9p/idpool.c (mode:100644)
@@ -0,0 +1,150 @@
+/*
+ * linux/fs/9p/idpool.c
+ *
+ * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
+ * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <asm/semaphore.h>
+#include <linux/config.h>
+#include "idpool.h"
+#include "debug.h"
+
+/**
+ * grow_idpool - increase the size of an id pool
+ * @i: pointer to idpool to initialize
+ * @size: size (in bits) of idpool
+ *
+ */
+
+static int grow_idpool(struct idpool *i, int newsize)
+{
+ unsigned long *newpool;
+
+ newpool = kmalloc((newsize / 8), GFP_KERNEL);
+ if (!newpool) {
+ eprintk(KERN_WARNING,
+ "Couldn't allocate memory to grow idpool\n");
+ return 0;
+ }
+
+ memset(newpool, 0, newsize / 8);
+ if (i->idlist) {
+ memcpy(newpool, i->idlist, (i->maxalloc) / 8);
+ kfree(i->idlist);
+ }
+
+ i->idlist = newpool;
+ i->maxalloc = newsize;
+
+ return newsize;
+}
+
+/**
+ * v9fs_alloc_idpool - allocate an id pool
+ * @i: pointer to idpool to initialize
+ * @size: size of idpool
+ *
+ */
+
+int v9fs_alloc_idpool(struct idpool *i, int size)
+{
+ int newsize;
+
+ init_MUTEX(&i->sem);
+ i->maxalloc = 0;
+ i->numalloc = 0;
+ i->lastfree = 0;
+ i->idlist = NULL;
+ newsize = grow_idpool(i, size);
+ return newsize;
+}
+
+/**
+ * v9fs_free_idpool - deallocate an id pool
+ * @i: pointer to idpool to free
+ *
+ */
+
+void v9fs_free_idpool(struct idpool *i)
+{
+ kfree(i->idlist);
+}
+
+/**
+ * v9fs_get_idpool - get a new id from the pool
+ * @i: pointer to idpool
+ *
+ */
+
+int v9fs_get_idpool(struct idpool *i)
+{
+ int nextbit;
+
+ if (down_interruptible(&i->sem) == -EINTR) {
+ eprintk(KERN_WARNING, "Interrupted while locking\n");
+ return -1;
+ }
+
+ nextbit = find_next_zero_bit(i->idlist, i->maxalloc, i->lastfree);
+ if (nextbit > i->maxalloc) {
+ if (grow_idpool(i, i->maxalloc * 2) == 0) {
+ up(&i->sem);
+ return -1;
+ } else {
+ nextbit =
+ find_next_zero_bit(i->idlist, i->maxalloc,
+ i->lastfree);
+ }
+ }
+
+ set_bit(nextbit, i->idlist);
+ if (i->lastfree == nextbit)
+ i->lastfree = nextbit + 1;
+
+ up(&i->sem);
+ return nextbit;
+}
+
+/**
+ * v9fs_put_idpool - get a new id from the pool
+ * @which: which id to put
+ * @i: pointer to idpool
+ *
+ */
+
+void v9fs_put_idpool(int which, struct idpool *i)
+{
+ if ((which < 0) || (which > i->maxalloc)) {
+ return;
+ }
+
+ if (down_interruptible(&i->sem) == -EINTR) {
+ eprintk(KERN_WARNING, "Interrupted while locking\n");
+ return;
+ }
+
+ clear_bit(which, i->idlist);
+ if (which < i->lastfree)
+ i->lastfree = which;
+
+ up(&i->sem);
+}
-
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