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![Kirill A. Shutemov](/assets/img/avatar_default.png)
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
270 lines
6.3 KiB
C
270 lines
6.3 KiB
C
/* 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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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/pagemap.h>
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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 "internal.h"
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static struct dentry *afs_mntpt_lookup(struct inode *dir,
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struct dentry *dentry,
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unsigned int flags);
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static int afs_mntpt_open(struct inode *inode, struct file *file);
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static void afs_mntpt_expiry_timed_out(struct work_struct *work);
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const struct file_operations afs_mntpt_file_operations = {
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.open = afs_mntpt_open,
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.llseek = noop_llseek,
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};
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const struct inode_operations afs_mntpt_inode_operations = {
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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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};
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const struct inode_operations afs_autocell_inode_operations = {
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.getattr = afs_getattr,
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};
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static LIST_HEAD(afs_vfsmounts);
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static DECLARE_DELAYED_WORK(afs_mntpt_expiry_timer, afs_mntpt_expiry_timed_out);
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static unsigned long afs_mntpt_expiry_timeout = 10 * 60;
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/*
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* check a symbolic link to see whether it actually encodes a mountpoint
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* - sets the AFS_VNODE_MOUNTPOINT flag on the vnode appropriately
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*/
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int afs_mntpt_check_symlink(struct afs_vnode *vnode, struct key *key)
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{
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struct page *page;
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size_t size;
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char *buf;
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int ret;
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_enter("{%x:%u,%u}",
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vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);
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/* read the contents of the symlink into the pagecache */
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page = read_cache_page(AFS_VNODE_TO_I(vnode)->i_mapping, 0,
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afs_page_filler, key);
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if (IS_ERR(page)) {
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ret = PTR_ERR(page);
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goto out;
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}
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ret = -EIO;
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if (PageError(page))
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goto out_free;
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buf = kmap(page);
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/* examine the symlink's contents */
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size = vnode->status.size;
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_debug("symlink to %*.*s", (int) size, (int) size, buf);
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if (size > 2 &&
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(buf[0] == '%' || buf[0] == '#') &&
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buf[size - 1] == '.'
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) {
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_debug("symlink is a mountpoint");
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spin_lock(&vnode->lock);
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set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
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vnode->vfs_inode.i_flags |= S_AUTOMOUNT;
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spin_unlock(&vnode->lock);
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}
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ret = 0;
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kunmap(page);
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out_free:
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put_page(page);
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out:
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_leave(" = %d", ret);
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return ret;
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}
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/*
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* no valid lookup procedure on this sort of dir
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*/
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static struct dentry *afs_mntpt_lookup(struct inode *dir,
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struct dentry *dentry,
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unsigned int flags)
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{
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_enter("%p,%p{%pd2}", dir, dentry, dentry);
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return ERR_PTR(-EREMOTE);
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}
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/*
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* no valid open procedure on this sort of dir
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*/
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static int afs_mntpt_open(struct inode *inode, struct file *file)
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{
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_enter("%p,%p{%pD2}", inode, file, file);
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return -EREMOTE;
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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 *super;
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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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_enter("{%pd}", mntpt);
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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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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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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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ret = -ENOENT;
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if (size < 2 || size > AFS_MAXCELLNAME)
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goto error_no_page;
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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, 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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ret = -EINVAL;
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if (size > PAGE_SIZE - 1)
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goto error_no_page;
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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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ret = -EIO;
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if (PageError(page))
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goto error;
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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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/* work out what options we want */
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super = AFS_FS_S(mntpt->d_sb);
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memcpy(options, "cell=", 5);
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strcpy(options + 5, super->volume->cell->name);
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if (super->volume->type == AFSVL_RWVOL || rwpath)
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strcat(options, ",rwpath");
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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_kern_mount(&afs_fs_type, 0, devname, options);
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_debug("--- mount result %p ---", mnt);
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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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return mnt;
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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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/*
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* handle an automount point
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*/
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struct vfsmount *afs_d_automount(struct path *path)
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{
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struct vfsmount *newmnt;
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_enter("{%pd}", path->dentry);
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newmnt = afs_mntpt_do_automount(path->dentry);
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if (IS_ERR(newmnt))
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return newmnt;
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mntget(newmnt); /* prevent immediate expiration */
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mnt_set_expiry(newmnt, &afs_vfsmounts);
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queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
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afs_mntpt_expiry_timeout * HZ);
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_leave(" = %p", newmnt);
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return newmnt;
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}
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/*
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* handle mountpoint expiry timer going off
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*/
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static void afs_mntpt_expiry_timed_out(struct work_struct *work)
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{
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_enter("");
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if (!list_empty(&afs_vfsmounts)) {
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mark_mounts_for_expiry(&afs_vfsmounts);
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queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
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afs_mntpt_expiry_timeout * HZ);
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}
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_leave("");
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}
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/*
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* kill the AFS mountpoint timer if it's still running
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*/
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void afs_mntpt_kill_timer(void)
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{
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_enter("");
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ASSERT(list_empty(&afs_vfsmounts));
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cancel_delayed_work_sync(&afs_mntpt_expiry_timer);
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}
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