[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit
Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/os/linux/linux-3.4.x/fs/9p/fid.c b/ap/os/linux/linux-3.4.x/fs/9p/fid.c
new file mode 100644
index 0000000..da8eefb
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/fs/9p/fid.c
@@ -0,0 +1,309 @@
+/*
+ * V9FS FID Management
+ *
+ * Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
+ * Copyright (C) 2005, 2006 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 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/errno.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/idr.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+
+#include "v9fs.h"
+#include "v9fs_vfs.h"
+#include "fid.h"
+
+/**
+ * v9fs_fid_add - add a fid to a dentry
+ * @dentry: dentry that the fid is being added to
+ * @fid: fid to add
+ *
+ */
+
+int v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
+{
+ struct v9fs_dentry *dent;
+
+ p9_debug(P9_DEBUG_VFS, "fid %d dentry %s\n",
+ fid->fid, dentry->d_name.name);
+
+ dent = dentry->d_fsdata;
+ if (!dent) {
+ dent = kmalloc(sizeof(struct v9fs_dentry), GFP_KERNEL);
+ if (!dent)
+ return -ENOMEM;
+
+ spin_lock_init(&dent->lock);
+ INIT_LIST_HEAD(&dent->fidlist);
+ dentry->d_fsdata = dent;
+ }
+
+ spin_lock(&dent->lock);
+ list_add(&fid->dlist, &dent->fidlist);
+ spin_unlock(&dent->lock);
+
+ return 0;
+}
+
+/**
+ * v9fs_fid_find - retrieve a fid that belongs to the specified uid
+ * @dentry: dentry to look for fid in
+ * @uid: return fid that belongs to the specified user
+ * @any: if non-zero, return any fid associated with the dentry
+ *
+ */
+
+static struct p9_fid *v9fs_fid_find(struct dentry *dentry, u32 uid, int any)
+{
+ struct v9fs_dentry *dent;
+ struct p9_fid *fid, *ret;
+
+ p9_debug(P9_DEBUG_VFS, " dentry: %s (%p) uid %d any %d\n",
+ dentry->d_name.name, dentry, uid, any);
+ dent = (struct v9fs_dentry *) dentry->d_fsdata;
+ ret = NULL;
+ if (dent) {
+ spin_lock(&dent->lock);
+ list_for_each_entry(fid, &dent->fidlist, dlist) {
+ if (any || fid->uid == uid) {
+ ret = fid;
+ break;
+ }
+ }
+ spin_unlock(&dent->lock);
+ }
+
+ return ret;
+}
+
+/*
+ * We need to hold v9ses->rename_sem as long as we hold references
+ * to returned path array. Array element contain pointers to
+ * dentry names.
+ */
+static int build_path_from_dentry(struct v9fs_session_info *v9ses,
+ struct dentry *dentry, char ***names)
+{
+ int n = 0, i;
+ char **wnames;
+ struct dentry *ds;
+
+ for (ds = dentry; !IS_ROOT(ds); ds = ds->d_parent)
+ n++;
+
+ wnames = kmalloc(sizeof(char *) * n, GFP_KERNEL);
+ if (!wnames)
+ goto err_out;
+
+ for (ds = dentry, i = (n-1); i >= 0; i--, ds = ds->d_parent)
+ wnames[i] = (char *)ds->d_name.name;
+
+ *names = wnames;
+ return n;
+err_out:
+ return -ENOMEM;
+}
+
+static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
+ uid_t uid, int any)
+{
+ struct dentry *ds;
+ char **wnames, *uname;
+ int i, n, l, clone, access;
+ struct v9fs_session_info *v9ses;
+ struct p9_fid *fid, *old_fid = NULL;
+
+ v9ses = v9fs_dentry2v9ses(dentry);
+ access = v9ses->flags & V9FS_ACCESS_MASK;
+ fid = v9fs_fid_find(dentry, uid, any);
+ if (fid)
+ return fid;
+ /*
+ * we don't have a matching fid. To do a TWALK we need
+ * parent fid. We need to prevent rename when we want to
+ * look at the parent.
+ */
+ down_read(&v9ses->rename_sem);
+ ds = dentry->d_parent;
+ fid = v9fs_fid_find(ds, uid, any);
+ if (fid) {
+ /* Found the parent fid do a lookup with that */
+ fid = p9_client_walk(fid, 1, (char **)&dentry->d_name.name, 1);
+ goto fid_out;
+ }
+ up_read(&v9ses->rename_sem);
+
+ /* start from the root and try to do a lookup */
+ fid = v9fs_fid_find(dentry->d_sb->s_root, uid, any);
+ if (!fid) {
+ /* the user is not attached to the fs yet */
+ if (access == V9FS_ACCESS_SINGLE)
+ return ERR_PTR(-EPERM);
+
+ if (v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses))
+ uname = NULL;
+ else
+ uname = v9ses->uname;
+
+ fid = p9_client_attach(v9ses->clnt, NULL, uname, uid,
+ v9ses->aname);
+ if (IS_ERR(fid))
+ return fid;
+
+ v9fs_fid_add(dentry->d_sb->s_root, fid);
+ }
+ /* If we are root ourself just return that */
+ if (dentry->d_sb->s_root == dentry)
+ return fid;
+ /*
+ * Do a multipath walk with attached root.
+ * When walking parent we need to make sure we
+ * don't have a parallel rename happening
+ */
+ down_read(&v9ses->rename_sem);
+ n = build_path_from_dentry(v9ses, dentry, &wnames);
+ if (n < 0) {
+ fid = ERR_PTR(n);
+ goto err_out;
+ }
+ clone = 1;
+ i = 0;
+ while (i < n) {
+ l = min(n - i, P9_MAXWELEM);
+ /*
+ * We need to hold rename lock when doing a multipath
+ * walk to ensure none of the patch component change
+ */
+ fid = p9_client_walk(fid, l, &wnames[i], clone);
+ if (IS_ERR(fid)) {
+ if (old_fid) {
+ /*
+ * If we fail, clunk fid which are mapping
+ * to path component and not the last component
+ * of the path.
+ */
+ p9_client_clunk(old_fid);
+ }
+ kfree(wnames);
+ goto err_out;
+ }
+ old_fid = fid;
+ i += l;
+ clone = 0;
+ }
+ kfree(wnames);
+fid_out:
+ if (!IS_ERR(fid))
+ v9fs_fid_add(dentry, fid);
+err_out:
+ up_read(&v9ses->rename_sem);
+ return fid;
+}
+
+/**
+ * v9fs_fid_lookup - lookup for a fid, try to walk if not found
+ * @dentry: dentry to look for fid in
+ *
+ * Look for a fid in the specified dentry for the current user.
+ * If no fid is found, try to create one walking from a fid from the parent
+ * dentry (if it has one), or the root dentry. If the user haven't accessed
+ * the fs yet, attach now and walk from the root.
+ */
+
+struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
+{
+ uid_t uid;
+ int any, access;
+ struct v9fs_session_info *v9ses;
+
+ v9ses = v9fs_dentry2v9ses(dentry);
+ access = v9ses->flags & V9FS_ACCESS_MASK;
+ switch (access) {
+ case V9FS_ACCESS_SINGLE:
+ case V9FS_ACCESS_USER:
+ case V9FS_ACCESS_CLIENT:
+ uid = current_fsuid();
+ any = 0;
+ break;
+
+ case V9FS_ACCESS_ANY:
+ uid = v9ses->uid;
+ any = 1;
+ break;
+
+ default:
+ uid = ~0;
+ any = 0;
+ break;
+ }
+ return v9fs_fid_lookup_with_uid(dentry, uid, any);
+}
+
+struct p9_fid *v9fs_fid_clone(struct dentry *dentry)
+{
+ struct p9_fid *fid, *ret;
+
+ fid = v9fs_fid_lookup(dentry);
+ if (IS_ERR(fid))
+ return fid;
+
+ ret = p9_client_walk(fid, 0, NULL, 1);
+ return ret;
+}
+
+static struct p9_fid *v9fs_fid_clone_with_uid(struct dentry *dentry, uid_t uid)
+{
+ struct p9_fid *fid, *ret;
+
+ fid = v9fs_fid_lookup_with_uid(dentry, uid, 0);
+ if (IS_ERR(fid))
+ return fid;
+
+ ret = p9_client_walk(fid, 0, NULL, 1);
+ return ret;
+}
+
+struct p9_fid *v9fs_writeback_fid(struct dentry *dentry)
+{
+ int err;
+ struct p9_fid *fid;
+
+ fid = v9fs_fid_clone_with_uid(dentry, 0);
+ if (IS_ERR(fid))
+ goto error_out;
+ /*
+ * writeback fid will only be used to write back the
+ * dirty pages. We always request for the open fid in read-write
+ * mode so that a partial page write which result in page
+ * read can work.
+ */
+ err = p9_client_open(fid, O_RDWR);
+ if (err < 0) {
+ p9_client_clunk(fid);
+ fid = ERR_PTR(err);
+ goto error_out;
+ }
+error_out:
+ return fid;
+}