add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/fs/afs/mntpt.c
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..
@@ -1,12 +1,8 @@
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+// SPDX-License-Identifier: GPL-2.0-or-later
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 /* mountpoint management
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  *
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  * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
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  * Written by David Howells (dhowells@redhat.com)
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- *
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- * This program is free software; you can redistribute it and/or
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- * modify it under the terms of the GNU General Public License
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- * as published by the Free Software Foundation; either version
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- * 2 of the License, or (at your option) any later version.
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  */
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7
 
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 #include <linux/kernel.h>
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@@ -17,6 +13,7 @@
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 #include <linux/mount.h>
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 #include <linux/namei.h>
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 #include <linux/gfp.h>
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+#include <linux/fs_context.h>
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 #include "internal.h"
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18
 
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..
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@@ -35,7 +32,6 @@
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 	.lookup		= afs_mntpt_lookup,
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 	.readlink	= page_readlink,
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 	.getattr	= afs_getattr,
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-	.listxattr	= afs_listxattr,
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 };
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 const struct inode_operations afs_autocell_inode_operations = {
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@@ -46,6 +42,8 @@
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 static DECLARE_DELAYED_WORK(afs_mntpt_expiry_timer, afs_mntpt_expiry_timed_out);
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43
 
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 static unsigned long afs_mntpt_expiry_timeout = 10 * 60;
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+
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+static const char afs_root_volume[] = "root.cell";
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 /*
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  * no valid lookup procedure on this sort of dir
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@@ -68,107 +66,114 @@
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 }
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 /*
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+ * Set the parameters for the proposed superblock.
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+ */
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+static int afs_mntpt_set_params(struct fs_context *fc, struct dentry *mntpt)
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+{
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+	struct afs_fs_context *ctx = fc->fs_private;
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+	struct afs_super_info *src_as = AFS_FS_S(mntpt->d_sb);
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+	struct afs_vnode *vnode = AFS_FS_I(d_inode(mntpt));
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+	struct afs_cell *cell;
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+	const char *p;
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+	int ret;
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+
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+	if (fc->net_ns != src_as->net_ns) {
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+		put_net(fc->net_ns);
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+		fc->net_ns = get_net(src_as->net_ns);
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+	}
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+
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+	if (src_as->volume && src_as->volume->type == AFSVL_RWVOL) {
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+		ctx->type = AFSVL_RWVOL;
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+		ctx->force = true;
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+	}
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+	if (ctx->cell) {
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+		afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_mntpt);
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+		ctx->cell = NULL;
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+	}
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+	if (test_bit(AFS_VNODE_PSEUDODIR, &vnode->flags)) {
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+		/* if the directory is a pseudo directory, use the d_name */
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+		unsigned size = mntpt->d_name.len;
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+
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+		if (size < 2)
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+			return -ENOENT;
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+
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+		p = mntpt->d_name.name;
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+		if (mntpt->d_name.name[0] == '.') {
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+			size--;
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+			p++;
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+			ctx->type = AFSVL_RWVOL;
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+			ctx->force = true;
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+		}
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+		if (size > AFS_MAXCELLNAME)
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+			return -ENAMETOOLONG;
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+
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+		cell = afs_lookup_cell(ctx->net, p, size, NULL, false);
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+		if (IS_ERR(cell)) {
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+			pr_err("kAFS: unable to lookup cell '%pd'\n", mntpt);
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+			return PTR_ERR(cell);
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+		}
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+		ctx->cell = cell;
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+
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+		ctx->volname = afs_root_volume;
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+		ctx->volnamesz = sizeof(afs_root_volume) - 1;
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+	} else {
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+		/* read the contents of the AFS special symlink */
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+		struct page *page;
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+		loff_t size = i_size_read(d_inode(mntpt));
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+		char *buf;
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+
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+		if (src_as->cell)
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+			ctx->cell = afs_use_cell(src_as->cell, afs_cell_trace_use_mntpt);
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+
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+		if (size < 2 || size > PAGE_SIZE - 1)
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+			return -EINVAL;
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+
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+		page = read_mapping_page(d_inode(mntpt)->i_mapping, 0, NULL);
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+		if (IS_ERR(page))
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+			return PTR_ERR(page);
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+
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+		if (PageError(page)) {
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+			ret = afs_bad(AFS_FS_I(d_inode(mntpt)), afs_file_error_mntpt);
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+			put_page(page);
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+			return ret;
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+		}
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+
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+		buf = kmap(page);
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+		ret = -EINVAL;
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+		if (buf[size - 1] == '.')
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+			ret = vfs_parse_fs_string(fc, "source", buf, size - 1);
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+		kunmap(page);
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+		put_page(page);
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+		if (ret < 0)
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+			return ret;
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+	}
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+
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+	return 0;
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+}
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+
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+/*
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  * create a vfsmount to be automounted
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  */
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 static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt)
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 {
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-	struct afs_super_info *as;
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+	struct fs_context *fc;
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 	struct vfsmount *mnt;
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-	struct afs_vnode *vnode;
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-	struct page *page;
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-	char *devname, *options;
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-	bool rwpath = false;
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 	int ret;
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-
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-	_enter("{%pd}", mntpt);
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162
 
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 	BUG_ON(!d_inode(mntpt));
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-	ret = -ENOMEM;
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-	devname = (char *) get_zeroed_page(GFP_KERNEL);
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-	if (!devname)
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-		goto error_no_devname;
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+	fc = fs_context_for_submount(&afs_fs_type, mntpt);
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+	if (IS_ERR(fc))
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+		return ERR_CAST(fc);
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-	options = (char *) get_zeroed_page(GFP_KERNEL);
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-	if (!options)
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-		goto error_no_options;
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+	ret = afs_mntpt_set_params(fc, mntpt);
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+	if (!ret)
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+		mnt = fc_mount(fc);
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+	else
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+		mnt = ERR_PTR(ret);
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-	vnode = AFS_FS_I(d_inode(mntpt));
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-	if (test_bit(AFS_VNODE_PSEUDODIR, &vnode->flags)) {
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-		/* if the directory is a pseudo directory, use the d_name */
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-		static const char afs_root_cell[] = ":root.cell.";
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-		unsigned size = mntpt->d_name.len;
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-
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-		ret = -ENOENT;
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-		if (size < 2 || size > AFS_MAXCELLNAME)
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-			goto error_no_page;
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-
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-		if (mntpt->d_name.name[0] == '.') {
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-			devname[0] = '%';
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-			memcpy(devname + 1, mntpt->d_name.name + 1, size - 1);
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-			memcpy(devname + size, afs_root_cell,
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-			       sizeof(afs_root_cell));
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-			rwpath = true;
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-		} else {
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-			devname[0] = '#';
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-			memcpy(devname + 1, mntpt->d_name.name, size);
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-			memcpy(devname + size + 1, afs_root_cell,
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-			       sizeof(afs_root_cell));
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-		}
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-	} else {
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-		/* read the contents of the AFS special symlink */
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-		loff_t size = i_size_read(d_inode(mntpt));
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-		char *buf;
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-
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-		ret = -EINVAL;
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-		if (size > PAGE_SIZE - 1)
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-			goto error_no_page;
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-
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-		page = read_mapping_page(d_inode(mntpt)->i_mapping, 0, NULL);
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-		if (IS_ERR(page)) {
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-			ret = PTR_ERR(page);
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-			goto error_no_page;
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-		}
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-
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-		ret = -EIO;
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-		if (PageError(page))
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-			goto error;
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-
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-		buf = kmap_atomic(page);
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-		memcpy(devname, buf, size);
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-		kunmap_atomic(buf);
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-		put_page(page);
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-		page = NULL;
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-	}
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-
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-	/* work out what options we want */
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-	as = AFS_FS_S(mntpt->d_sb);
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-	if (as->cell) {
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-		memcpy(options, "cell=", 5);
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-		strcpy(options + 5, as->cell->name);
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-		if ((as->volume && as->volume->type == AFSVL_RWVOL) || rwpath)
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-			strcat(options, ",rwpath");
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-	}
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-
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-	/* try and do the mount */
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-	_debug("--- attempting mount %s -o %s ---", devname, options);
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-	mnt = vfs_submount(mntpt, &afs_fs_type, devname, options);
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-	_debug("--- mount result %p ---", mnt);
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-
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-	free_page((unsigned long) devname);
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-	free_page((unsigned long) options);
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-	_leave(" = %p", mnt);
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+	put_fs_context(fc);
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 	return mnt;
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-
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-error:
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-	put_page(page);
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-error_no_page:
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-	free_page((unsigned long) options);
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-error_no_options:
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-	free_page((unsigned long) devname);
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-error_no_devname:
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-	_leave(" = %d", ret);
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-	return ERR_PTR(ret);
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 }
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 /*