Sample ramfs file server that uses the in-kernel 9P file server support.
This code is for reference only.
Signed-off-by: Latchesar Ionkov <lucho@xxxxxxxxxx>
---
net/9p/Kconfig | 8 +-
net/9p/Makefile | 1 +
net/9p/ramfs/ramfs.c | 986 ++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 994 insertions(+), 1 deletions(-)
diff --git a/net/9p/Kconfig b/net/9p/Kconfig
index 5b0dc28..68f7496 100644
--- a/net/9p/Kconfig
+++ b/net/9p/Kconfig
@@ -23,11 +23,17 @@ config NET_9P_FD
file descriptors. TCP/IP is the default transport for 9p,
so if you are going to use 9p, you'll likely want this.
-config NET_9P_SRV
+menuconfig NET_9P_SRV
tristate "9P server support"
depends on NET_9P
help
Say Y if you want the 9P server support
+
+config NET_9P_RAMFS
+ tristate "9P ramfs sample file server"
+ depends on NET_9P_SRV && NET_9P_LOOP
+ help
+ Say Y if you want the 9P ramfs support
config NET_9P_VIRTIO
depends on NET_9P && EXPERIMENTAL && VIRTIO
tristate "9P Virtio Transport (Experimental)"
diff --git a/net/9p/Makefile b/net/9p/Makefile
index 6ee024e..3808c40 100644
--- a/net/9p/Makefile
+++ b/net/9p/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_NET_9P_FD) += 9pnet_fd.o
obj-$(CONFIG_NET_9P_LOOP) += 9pnet_loop.o
obj-$(CONFIG_NET_9P_SRV) += 9psrv.o
obj-$(CONFIG_NET_9P_VIRTIO) += 9pnet_virtio.o
+obj-$(CONFIG_NET_9P_RAMFS) += ramfs/
9pnet-objs := \
mod.o \
diff --git a/net/9p/ramfs/ramfs.c b/net/9p/ramfs/ramfs.c
new file mode 100644
index 0000000..3aff620
--- /dev/null
+++ b/net/9p/ramfs/ramfs.c
@@ -0,0 +1,986 @@
+/*
+ * net/9p/srv/ramfs.c
+ *
+ * Simple RAM filesystem
+ *
+ * Copyright (C) 2007 by Latchesar Ionkov <lucho@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * 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:
+ * Free Software Foundation
+ * 51 Franklin Street, Fifth Floor
+ * Boston, MA 02111-1301 USA
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/parser.h>
+#include <net/9p/9p.h>
+#include <net/9p/transport.h>
+#include <net/9p/srv.h>
+
+#define ROOTPERM 0777
+
+struct ramfs_file {
+ struct mutex lock; /* file lock */
+ atomic_t refcount;
+ unsigned long status;
+ char *name;
+ u32 perm;
+ u64 length;
+ u32 atime;
+ u32 mtime;
+ u32 uid;
+ u32 gid;
+ u32 muid;
+ char *extension;
+ struct p9_qid qid;
+ int excl;
+
+ struct ramfs_file *parent;
+ struct ramfs_file *next; /* protected by parent lock */
+ struct ramfs_file *prev;
+
+ struct ramfs_file *dirents; /* if directory */
+ struct ramfs_file *dirlast;
+
+ struct list_head fid_list; /* all fids for a file */
+
+ u8 *data;
+ u64 datasize;
+};
+
+struct ramfs_fid {
+ struct ramfs_file *file;
+ int omode;
+ u64 diroffset;
+ struct ramfs_file *dirent;
+ struct list_head fid_list; /* all fids for a file */
+};
+
+enum {
+ Removed = 1,
+};
+
+static struct p9srv_type *ramfs_srv_type;
+static struct ramfs_file *root;
+static u64 qidpath;
+static int blksize = 8192;
+
+static char *Enospace = "no space left";
+static char *Einternal = "internal error";
+
+static void ramfs_attach(struct p9srv_req *req);
+static void ramfs_walk(struct p9srv_req *req);
+static void ramfs_open(struct p9srv_req *req);
+static void ramfs_create(struct p9srv_req *req);
+static void ramfs_read(struct p9srv_req *req);
+static void ramfs_write(struct p9srv_req *req);
+static void ramfs_clunk(struct p9srv_req *req);
+static void ramfs_remove(struct p9srv_req *req);
+static void ramfs_stat(struct p9srv_req *req);
+static void ramfs_wstat(struct p9srv_req *req);
+static void ramfs_fiddestroy(struct p9srv_fid *fid);
+static void ramfs_connopen(struct p9srv_conn *conn);
+static void ramfs_connclose(struct p9srv_conn *conn);
+
+static char *p9_strdup(struct p9_str *str)
+{
+ char *ret;
+
+ ret = kmalloc(str->len + 1, GFP_KERNEL);
+ memmove(ret, str->str, str->len);
+ ret[str->len] = '\0';
+
+ return ret;
+}
+
+static void file_incref(struct ramfs_file *f)
+{
+ if (!f)
+ return;
+
+ atomic_inc(&f->refcount);
+ P9_DPRINTK(P9SRV_DEBUG_FS, "file %p %s count %d\n", f, f->name,
+ atomic_read(&f->refcount));
+}
+
+static void file_decrefimpl(struct ramfs_file *f, int lock)
+{
+ int n;
+
+ if (!f)
+ return;
+
+ n = atomic_dec_and_test(&f->refcount);
+ P9_DPRINTK(P9SRV_DEBUG_FS, "file %p %s count %d\n", f, f->name,
+ atomic_read(&f->refcount));
+ if (n) {
+ P9_DPRINTK(P9SRV_DEBUG_FS, "file %p %s destroy\n", f, f->name);
+ if (lock)
+ mutex_lock(&f->lock);
+
+ kfree(f->name);
+ kfree(f->extension);
+ kfree(f->data);
+ if (lock)
+ mutex_unlock(&f->lock);
+ kfree(f);
+ }
+}
+
+static void file_decref0(struct ramfs_file *f)
+{
+ return file_decrefimpl(f, 0);
+}
+
+static void file_decref(struct ramfs_file *f)
+{
+ return file_decrefimpl(f, 1);
+}
+
+static int file_truncate(struct ramfs_file *f, u32 size)
+{
+ int n;
+ u8 *buf;
+
+ if (size == 0) {
+ kfree(f->data);
+ f->data = NULL;
+ f->datasize = 0;
+ return 0;
+ }
+
+ n = (size/blksize + (size%blksize?1:0)) * blksize;
+ if (n <= f->datasize)
+ return 0;
+
+ buf = kmalloc(n, GFP_KERNEL);
+ if (!buf)
+ return -1;
+
+ memmove(buf, f->data, f->length);
+ kfree(f->data);
+ f->data = buf;
+ f->datasize = n;
+ return 0;
+}
+
+static struct ramfs_file *
+find_file(struct ramfs_file *dir, char *name, int lock)
+{
+ struct ramfs_file *ret;
+ struct ramfs_file *f;
+
+ if (strcmp(name, "..") == 0)
+ return dir->parent;
+
+ ret = NULL;
+ if (lock)
+ mutex_lock(&dir->lock);
+
+ for (f = dir->dirents; f != NULL; f = f->next) {
+ P9_DPRINTK(P9SRV_DEBUG_FS, "dir %p '%s' child %p '%s'\n", dir,
+ dir->name, f, f->name);
+
+ if (strcmp(name, f->name) == 0) {
+ ret = f;
+ file_incref(f);
+ break;
+ }
+ }
+
+ if (lock)
+ mutex_unlock(&dir->lock);
+
+ return ret;
+}
+
+static int check_perm(struct p9srv_req *req, struct ramfs_file *dir,
+ u32 uid, int perm)
+{
+ int n;
+
+ if (!perm)
+ return 1;
+
+ n = dir->perm & 7;
+ if (dir->uid == uid) {
+ n |= (dir->perm >> 6) & 7;
+ n |= (dir->perm >> 3) & 7;
+ }
+
+ if (!(n & perm)) {
+ p9srv_respond_error(req, Eperm, EPERM);
+ return 0;
+ }
+
+ return 1;
+}
+
+/* called holding parent lock, if parent != NULL */
+static struct ramfs_file *file_create(struct ramfs_file *parent, char *name,
+ int perm, u32 uid, u32 gid)
+{
+ struct ramfs_file *file;
+
+ file = kmalloc(sizeof(*file), GFP_KERNEL);
+ mutex_init(&file->lock);
+ atomic_set(&file->refcount, 1);
+ file->status = 0;
+ file->name = name;
+ file->perm = perm;
+ file->length = 0;
+ file->atime = 0;
+ file->mtime = 0;
+ file->uid = uid;
+ file->gid = gid;
+ file->muid = uid;
+ file->extension = NULL;
+ file->excl = 0;
+
+ file->parent = parent;
+ file->next = NULL;
+ file->prev = NULL;
+ file->dirents = NULL;
+ file->dirlast = NULL;
+ file->data = NULL;
+ file->datasize = 0;
+ file_truncate(file, 0);
+ file->qid.type = perm >> 24;
+ file->qid.version = 0;
+ file->qid.path = qidpath++;
+ INIT_LIST_HEAD(&file->fid_list);
+
+ if (parent) {
+ if (parent->dirlast) {
+ parent->dirlast->next = file;
+ file->prev = parent->dirlast;
+ } else
+ parent->dirents = file;
+
+ parent->dirlast = file;
+ parent->muid = uid;
+/* parent->mtime = time(NULL); */
+ parent->qid.version++;
+ file_incref(parent);
+ }
+
+ P9_DPRINTK(P9SRV_DEBUG_FS, "file %p %s\n", file, file->name);
+ return file;
+}
+
+static void file2wstat(struct ramfs_file *f, struct p9_wstat *wstat)
+{
+ wstat->size = 0;
+ wstat->type = 0;
+ wstat->dev = 0;
+ wstat->qid = f->qid;
+ wstat->mode = f->perm;
+ wstat->atime = f->atime;
+ wstat->mtime = f->mtime;
+ wstat->length = f->length;
+ wstat->name = f->name;
+ wstat->uid = NULL;
+ wstat->gid = NULL;
+ wstat->muid = NULL;
+ wstat->extension = f->extension;
+ wstat->n_uid = f->uid;
+ wstat->n_gid = f->gid;
+ wstat->n_muid = f->muid;
+}
+
+static struct ramfs_fid *fid_alloc(struct ramfs_file *file)
+{
+ struct ramfs_fid *f;
+
+ f = kmalloc(sizeof(*f), GFP_KERNEL);
+ f->file = file;
+ file_incref(file);
+ f->omode = -1;
+ f->diroffset = 0;
+ f->dirent = NULL;
+ INIT_LIST_HEAD(&f->fid_list);
+
+ mutex_lock(&file->lock);
+ list_add_tail(&f->fid_list, &file->fid_list);
+ mutex_unlock(&file->lock);
+
+ P9_DPRINTK(P9SRV_DEBUG_FS, "fid %p file %s\n", f, file->name);
+ return f;
+}
+
+/* file is already incref-ed */
+static void fid_move(struct ramfs_fid *fid, struct ramfs_file *file)
+{
+ P9_DPRINTK(P9SRV_DEBUG_FS, "fid %p from %s to %s\n", fid,
+ fid->file->name, file->name);
+
+ mutex_lock(&fid->file->lock);
+ list_del(&fid->fid_list);
+ mutex_unlock(&fid->file->lock);
+ file_decref(fid->file);
+
+ fid->file = file;
+ mutex_lock(&fid->file->lock);
+ list_add(&fid->fid_list, &fid->file->fid_list);
+ mutex_unlock(&fid->file->lock);
+}
+
+static void ramfs_fiddestroy(struct p9srv_fid *fid)
+{
+ struct ramfs_fid *f;
+
+ f = fid->aux;
+ if (!f)
+ return;
+
+ mutex_lock(&f->file->lock);
+ list_del(&f->fid_list);
+ mutex_unlock(&f->file->lock);
+
+ file_decref(f->file);
+ file_decref(f->dirent);
+ kfree(f);
+}
+
+static void ramfs_attach(struct p9srv_req *req)
+{
+ int err;
+ struct ramfs_fid *fid;
+
+ if (req->afid != NULL) {
+ p9srv_respond_error(req, Enoauth, EIO);
+ return;
+ }
+
+ if (!check_perm(req, root, req->tcall->params.tattach.n_uname, 4))
+ return;
+
+ req->fid->uid = req->tcall->params.tattach.n_uname;
+ fid = fid_alloc(root);
+ req->fid->aux = fid;
+
+ err = p9_create_rattach(req->rcall, &fid->file->qid);
+ if (err < 0)
+ p9srv_respond_error(req, Einternal, err);
+ else
+ p9srv_respond(req, req->rcall);
+}
+
+static void ramfs_walk(struct p9srv_req *req)
+{
+ int i, err;
+ char *name;
+ struct ramfs_fid *fid, *nfid;
+ struct ramfs_file *nf;
+ struct p9_fcall *tc;
+ struct p9_qid wqids[P9_MAXWELEM];
+
+ P9_DPRINTK(P9SRV_DEBUG_FS, "fid %d nfid %d nwname %d\n", req->fid->fid,
+ req->newfid->fid, req->tcall->params.twalk.nwname);
+
+ if (req->fid != req->newfid) {
+ fid = req->fid->aux;
+ nfid = fid_alloc(fid->file);
+ req->newfid->aux = nfid;
+ }
+
+ tc = req->tcall;
+ if (tc->params.twalk.nwname == 0) {
+ i = 0;
+ goto done;
+ }
+
+ nfid = req->newfid->aux;
+ for (i = 0; i < tc->params.twalk.nwname; i++) {
+ name = p9_strdup(&tc->params.twalk.wnames[i]);
+ nf = find_file(nfid->file, name, 1);
+ kfree(name);
+ if (!nf)
+ break;
+
+ wqids[i] = nf->qid;
+ fid_move(nfid, nf);
+ }
+
+ if (i == 0) {
+ p9srv_respond_error(req, Enotfound, ENOENT);
+ return;
+ }
+
+done:
+ err = p9_create_rwalk(req->rcall, i, wqids);
+ if (err < 0)
+ p9srv_respond_error(req, Einternal, err);
+ else
+ p9srv_respond(req, req->rcall);
+}
+
+static void ramfs_open(struct p9srv_req *req)
+{
+ int m, mode, err;
+ struct ramfs_fid *fid;
+ struct ramfs_file *file;
+
+ err = 0;
+ fid = req->fid->aux;
+ mode = req->tcall->params.topen.mode;
+ m = 0;
+ switch (mode & 3) {
+ case P9_OREAD:
+ m = 4;
+ break;
+
+ case P9_OWRITE:
+ m = 2;
+ break;
+
+ case P9_ORDWR:
+ m = 6;
+ break;
+
+ case P9_OEXEC:
+ m = 1;
+ break;
+ }
+
+ if (mode & P9_OTRUNC)
+ m |= 2;
+
+ file = fid->file;
+ mutex_lock(&file->lock);
+ if (!check_perm(req, file, req->fid->uid, m))
+ goto done;
+
+ if (mode & P9_OTRUNC)
+ file_truncate(file, 0);
+
+ if (mode & P9_OEXCL) {
+ if (file->excl) {
+ p9srv_respond_error(req, Eopen, EPERM);
+ goto done;
+ }
+
+ file->excl = 1;
+ }
+
+ fid->omode = mode;
+ err = p9_create_ropen(req->rcall, &file->qid, 0);
+ if (err < 0)
+ p9srv_respond_error(req, Einternal, err);
+
+done:
+ mutex_unlock(&file->lock);
+ if (err >= 0)
+ p9srv_respond(req, req->rcall);
+}
+
+static void ramfs_create(struct p9srv_req *req)
+{
+ int mode, err;
+ u32 perm;
+ struct p9_fcall *tc;
+ struct ramfs_fid *fid;
+ struct ramfs_file *dir, *file, *nf;
+ char *sname;
+
+ err = 0;
+ tc = req->tcall;
+ perm = tc->params.tcreate.perm;
+ mode = tc->params.tcreate.mode;
+ sname = NULL;
+ file = NULL;
+
+ if (perm & P9_DMLINK) {
+ p9srv_respond_error(req, Eperm, EPERM);
+ goto done;
+ }
+
+ fid = req->fid->aux;
+ dir = fid->file;
+ sname = p9_strdup(&tc->params.tcreate.name);
+ P9_DPRINTK(P9SRV_DEBUG_FS, "name %s\n", sname);
+ if (!strcmp(sname, ".") || !strcmp(sname, "..")) {
+ p9srv_respond_error(req, Eexist, EEXIST);
+ goto done;
+ }
+
+ if (!check_perm(req, dir, req->fid->uid, 2))
+ goto done;
+
+ if (perm & P9_DMDIR)
+ perm &= ~0777 | (dir->perm & 0777);
+ else
+ perm &= ~0666 | (dir->perm & 0666);
+
+ mutex_lock(&dir->lock);
+ nf = find_file(dir, sname, 0);
+ if (nf) {
+ mutex_unlock(&dir->lock);
+ file_decref(nf);
+ p9srv_respond_error(req, Eexist, EEXIST);
+ goto done;
+ }
+
+ file = file_create(dir, sname, perm, dir->uid, 0);
+ mutex_unlock(&dir->lock);
+
+ fid->omode = mode;
+ file_incref(file);
+ fid_move(fid, file);
+ if (perm & (P9_DMNAMEDPIPE | P9_DMSYMLINK | P9_DMLINK | P9_DMDEVICE |
+ P9_DMSOCKET)) {
+
+ file->extension = p9_strdup(&tc->params.tcreate.extension);
+ } else {
+ if (mode & P9_OEXCL)
+ file->excl = 1;
+ }
+
+ P9_DPRINTK(P9SRV_DEBUG_FS, "file %p parent %p first child %p\n",
+ file, dir, dir->dirents);
+ err = p9_create_rcreate(req->rcall, &file->qid, 0);
+ if (err < 0)
+ p9srv_respond_error(req, Einternal, err);
+
+done:
+ if (!sname)
+ kfree(sname);
+
+ if (err >= 0)
+ p9srv_respond(req, req->rcall);
+}
+
+static void ramfs_read(struct p9srv_req *req)
+{
+ int i, n, count;
+ u64 offset;
+ struct p9_fcall *tc, *rc;
+ struct ramfs_fid *fid;
+ struct ramfs_file *file, *cf;
+ struct p9_wstat wstat;
+ u8 *data;
+
+ tc = req->tcall;
+ rc = req->rcall;
+ n = p9_init_rread(rc);
+ fid = req->fid->aux;
+ count = tc->params.tread.count;
+ offset = tc->params.tread.offset;
+ data = rc->params.rread.data;
+ file = fid->file;
+ if (file->perm & P9_DMDIR) {
+ mutex_lock(&file->lock);
+ if (offset == 0) {
+ file_decref(fid->dirent);
+ fid->dirent = file->dirents;
+ file_incref(fid->dirent);
+ fid->diroffset = 0;
+ }
+
+ cf = fid->dirent;
+ for (n = 0, cf = fid->dirent; (n < count) && (cf != NULL);
+ cf = cf->next) {
+ BUG_ON(test_bit(Removed, &cf->status));
+ file2wstat(cf, &wstat);
+ P9_DPRINTK(P9SRV_DEBUG_FS, "name %s\n", wstat.name);
+ i = p9_serialize_stat(&wstat, data + n, count - n - 1,
+ req->conn->dotu);
+ if (i == 0)
+ break;
+
+ n += i;
+ }
+
+ fid->diroffset += n;
+ file_incref(cf);
+ file_decref(fid->dirent);
+ fid->dirent = cf;
+ mutex_unlock(&file->lock);
+ } else {
+ n = count;
+ if (file->length < offset+count)
+ n = file->length - offset;
+
+ if (n < 0)
+ n = 0;
+
+ memmove(data, file->data + offset, n);
+ }
+
+/*
+ pthread_mutex_lock(&file->lock);
+ file->atime = time(NULL);
+ pthread_mutex_unlock(&file->lock);
+*/
+
+ p9_set_rread_count(rc, n);
+ p9srv_respond(req, rc);
+}
+
+static void ramfs_write(struct p9srv_req *req)
+{
+ int err;
+ u32 count;
+ u64 offset;
+ struct p9_fcall *tc;
+ struct ramfs_fid *fid;
+ struct ramfs_file *file;
+
+ tc = req->tcall;
+ offset = tc->params.twrite.offset;
+ count = tc->params.twrite.count;
+ fid = req->fid->aux;
+ file = fid->file;
+ if (req->fid->omode & P9_OAPPEND)
+ offset = file->length;
+
+ if (file->length < offset+count) {
+ mutex_lock(&file->lock);
+ if (file_truncate(file, offset+count)) {
+ mutex_unlock(&file->lock);
+ p9srv_respond_error(req, Enospace, ENOSPC);
+ return;
+ }
+
+ if (offset+count > file->datasize) {
+ if (file->datasize - offset > 0)
+ count = file->datasize - offset;
+ else
+ count = 0;
+ }
+
+ if (count) {
+ if (file->length < offset)
+ memset(file->data+file->length, 0,
+ offset - file->length);
+
+ file->length = offset+count;
+ }
+ mutex_unlock(&file->lock);
+ }
+
+ if (count)
+ memmove(file->data + offset, tc->params.twrite.data, count);
+
+ mutex_lock(&file->lock);
+ file->qid.version++;
+ file->muid = req->fid->uid;
+ mutex_unlock(&file->lock);
+
+ err = p9_create_rwrite(req->rcall, count);
+ if (err < 0)
+ p9srv_respond_error(req, Einternal, err);
+ else
+ p9srv_respond(req, req->rcall);
+}
+
+static void ramfs_clunk(struct p9srv_req *req)
+{
+ int err;
+
+ err = p9_create_rclunk(req->rcall);
+ if (err < 0)
+ p9srv_respond_error(req, Einternal, err);
+ else
+ p9srv_respond(req, req->rcall);
+}
+
+static void ramfs_remove(struct p9srv_req *req)
+{
+ int err;
+ struct p9_fcall *rc;
+ struct ramfs_fid *fid, *f;
+ struct ramfs_file *file;
+
+ err = 0;
+ rc = NULL;
+ fid = req->fid->aux;
+ file = fid->file;
+ P9_DPRINTK(P9SRV_DEBUG_FS, "fid %d name %s\n", req->fid->fid,
+ file->name);
+ mutex_lock(&file->lock);
+ if (file->perm & P9_DMDIR && file->dirents) {
+ mutex_unlock(&file->lock);
+ p9srv_respond_error(req, Enotempty, ENOTEMPTY);
+ return;
+ }
+ mutex_unlock(&file->lock);
+
+ mutex_lock(&file->parent->lock);
+ if (!check_perm(req, file->parent, req->fid->uid, 2))
+ goto done;
+
+ if (test_and_set_bit(Removed, &file->status))
+ goto respond;
+
+ if (file->parent->dirents == file)
+ file->parent->dirents = file->next;
+ else
+ file->prev->next = file->next;
+
+ if (file->next)
+ file->next->prev = file->prev;
+
+ if (file == file->parent->dirlast)
+ file->parent->dirlast = file->prev;
+
+ /* check if any fid has dirent set to the removed file */
+ list_for_each_entry(f, &file->parent->fid_list, fid_list) {
+ if (f->dirent == file) {
+ file_incref(file->next);
+ f->dirent = file->next;
+ file_decref(f->dirent);
+ }
+ }
+
+ file->prev = NULL;
+ file->next = NULL;
+
+ file->parent->muid = req->fid->uid;
+ file->parent->qid.version++;
+
+ file_decref(file);
+ file_decref0(file->parent);
+
+respond:
+ err = p9_create_rremove(req->rcall);
+
+done:
+ mutex_unlock(&file->parent->lock);
+ if (err < 0)
+ p9srv_respond_error(req, Einternal, err);
+ else
+ p9srv_respond(req, req->rcall);
+}
+
+static void ramfs_stat(struct p9srv_req *req)
+{
+ int err;
+ struct ramfs_fid *f;
+ struct p9_wstat wstat;
+
+ f = req->fid->aux;
+ file2wstat(f->file, &wstat);
+ err = p9_create_rstat(req->rcall, &wstat, req->conn->dotu);
+ if (err < 0)
+ p9srv_respond_error(req, Einternal, err);
+ else
+ p9srv_respond(req, req->rcall);
+}
+
+static void ramfs_wstat(struct p9srv_req *req)
+{
+ int lockparent, lockfile, err;
+ struct ramfs_fid *f;
+ struct ramfs_file *file, *nf;
+ struct p9_stat *stat;
+ struct p9_fcall *rc;
+ char *sname, *oldname;
+ u64 length, oldlength;
+ u32 oldperm;
+ u32 oldmtime;
+
+ rc = NULL;
+ err = 0;
+ oldlength = ~0;
+ oldperm = ~0;
+ oldmtime = ~0;
+ oldname = NULL;
+
+ f = req->fid->aux;
+ file = f->file;
+ stat = &req->tcall->params.twstat.stat;
+
+ mutex_lock(&file->lock);
+ lockfile = 1;
+
+ lockparent = stat->name.len != 0 && file->parent != file;
+ if (lockparent)
+ mutex_lock(&file->parent->lock);
+
+ oldname = NULL;
+ if (stat->name.len != 0) {
+ if (!check_perm(req, file->parent, req->fid->uid, 2))
+ goto out;
+
+ sname = p9_strdup(&stat->name);
+ nf = find_file(file->parent, sname, 0);
+
+ if (nf) {
+ kfree(sname);
+ p9srv_respond_error(req, Eexist, EEXIST);
+ goto out;
+ }
+
+ oldname = file->name;
+ file->name = sname;
+ }
+
+ if (stat->length != (u64) ~0) {
+ if (!check_perm(req, file, req->fid->uid, 2) ||
+ file->perm & P9_DMDIR)
+ goto out;
+
+ oldlength = file->length;
+ length = stat->length;
+ if (file_truncate(file, length)) {
+ p9srv_respond_error(req, Enospace, ENOSPC);
+ goto out;
+ }
+
+ if (length > file->datasize)
+ length = file->datasize;
+
+ if (file->length < length)
+ memset(file->data+file->length, 0, length-file->length);
+
+ file->length = length;
+ }
+
+ if (stat->mode != (u32) ~0) {
+ if (file->uid != req->fid->uid) {
+ p9srv_respond_error(req, Eperm, EPERM);
+ goto out;
+ }
+
+ oldperm = file->perm;
+ file->perm = stat->mode;
+ }
+
+ if (stat->mtime != (u32) ~0) {
+ if (file->uid != req->fid->uid) {
+ p9srv_respond_error(req, Eperm, EPERM);
+ goto out;
+ }
+
+ oldmtime = file->mtime;
+ file->mtime = stat->mtime;
+ }
+
+ err = p9_create_rwstat(req->rcall);
+ if (err < 0)
+ p9srv_respond_error(req, Einternal, err);
+ else
+ rc = req->rcall;
+
+out:
+ if (!rc) {
+ if (oldname) {
+ kfree(file->name);
+ file->name = oldname;
+ }
+
+ if (oldperm != ~0)
+ file->perm = oldperm;
+
+ if (oldmtime != ~0)
+ file->mtime = oldmtime;
+
+ if (oldlength != ~0) {
+ file->length = oldlength;
+ file_truncate(file, oldlength);
+ }
+ } else {
+ kfree(oldname);
+ if (stat->length != ~0) {
+ file_truncate(file, file->length);
+ memset(file->data + file->length, 0,
+ file->datasize - file->length);
+ }
+ }
+
+ if (lockparent)
+ mutex_unlock(&file->parent->lock);
+
+ if (lockfile)
+ mutex_unlock(&file->lock);
+
+ if (rc)
+ p9srv_respond(req, rc);
+}
+
+static void ramfs_connopen(struct p9srv_conn *conn)
+{
+ try_module_get(THIS_MODULE);
+}
+
+static void ramfs_connclose(struct p9srv_conn *conn)
+{
+ module_put(THIS_MODULE);
+}
+
+static void ramfs_destroy(struct p9srv *srv)
+{
+ module_put(THIS_MODULE);
+}
+
+static struct p9srv *ramfs_srv_create(void)
+{
+ char *s;
+ struct p9srv *srv;
+
+ srv = p9srv_srv_create();
+ if (IS_ERR(srv))
+ return srv;
+
+ srv->attach = ramfs_attach;
+ srv->walk = ramfs_walk;
+ srv->open = ramfs_open;
+ srv->create = ramfs_create;
+ srv->read = ramfs_read;
+ srv->write = ramfs_write;
+ srv->clunk = ramfs_clunk;
+ srv->remove = ramfs_remove;
+ srv->stat = ramfs_stat;
+ srv->wstat = ramfs_wstat;
+ srv->destroy = ramfs_destroy;
+ srv->fiddestroy = ramfs_fiddestroy;
+ srv->debuglevel = 0;
+ srv->connopen = ramfs_connopen;
+ srv->connclose = ramfs_connclose;
+
+ s = kmalloc(2, GFP_KERNEL);
+ *s = '\0';
+ root = file_create(NULL, s, ROOTPERM | P9_DMDIR, 0, 0);
+ file_incref(root);
+ root->parent = root;
+
+ try_module_get(THIS_MODULE);
+ p9srv_srv_start(srv);
+ return srv;
+}
+
+static int __init ramfs_init(void)
+{
+ ramfs_srv_type = p9srv_type_register("ramfs", ramfs_srv_create);
+ if (IS_ERR(ramfs_srv_type))
+ return PTR_ERR(ramfs_srv_type);
+
+ return 0;
+}
+
+static void __exit ramfs_exit(void)
+{
+ p9srv_type_unregister("ramfs");
+}
+
+module_init(ramfs_init)
+module_exit(ramfs_exit)
+
+MODULE_AUTHOR("Latchesar Ionkov <lucho@xxxxxxxxxx>");
+MODULE_LICENSE("GPL");
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