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linux/fs/minix/dir.c
Kirill A. Shutemov 09cbfeaf1a mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros 
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>
2016-04-04 10:41:08 -07:00

469 lines
11 KiB
C
Raw Blame History

/*
* linux/fs/minix/dir.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* minix directory handling functions
*
* Updated to filesystem version 3 by Daniel Aragones
*/
#include "minix.h"
#include <linux/buffer_head.h>
#include <linux/highmem.h>
#include <linux/swap.h>
typedef struct minix_dir_entry minix_dirent;
typedef struct minix3_dir_entry minix3_dirent;
static int minix_readdir(struct file *, struct dir_context *);
const struct file_operations minix_dir_operations = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
.iterate = minix_readdir,
.fsync = generic_file_fsync,
};
static inline void dir_put_page(struct page *page)
{
kunmap(page);
put_page(page);
}
/*
* Return the offset into page `page_nr' of the last valid
* byte in that page, plus one.
*/
static unsigned
minix_last_byte(struct inode *inode, unsigned long page_nr)
{
unsigned last_byte = PAGE_SIZE;
if (page_nr == (inode->i_size >> PAGE_SHIFT))
last_byte = inode->i_size & (PAGE_SIZE - 1);
return last_byte;
}
static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
{
struct address_space *mapping = page->mapping;
struct inode *dir = mapping->host;
int err = 0;
block_write_end(NULL, mapping, pos, len, len, page, NULL);
if (pos+len > dir->i_size) {
i_size_write(dir, pos+len);
mark_inode_dirty(dir);
}
if (IS_DIRSYNC(dir))
err = write_one_page(page, 1);
else
unlock_page(page);
return err;
}
static struct page * dir_get_page(struct inode *dir, unsigned long n)
{
struct address_space *mapping = dir->i_mapping;
struct page *page = read_mapping_page(mapping, n, NULL);
if (!IS_ERR(page))
kmap(page);
return page;
}
static inline void *minix_next_entry(void *de, struct minix_sb_info *sbi)
{
return (void*)((char*)de + sbi->s_dirsize);
}
static int minix_readdir(struct file *file, struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
struct super_block *sb = inode->i_sb;
struct minix_sb_info *sbi = minix_sb(sb);
unsigned chunk_size = sbi->s_dirsize;
unsigned long npages = dir_pages(inode);
unsigned long pos = ctx->pos;
unsigned offset;
unsigned long n;
ctx->pos = pos = ALIGN(pos, chunk_size);
if (pos >= inode->i_size)
return 0;
offset = pos & ~PAGE_MASK;
n = pos >> PAGE_SHIFT;
for ( ; n < npages; n++, offset = 0) {
char *p, *kaddr, *limit;
struct page *page = dir_get_page(inode, n);
if (IS_ERR(page))
continue;
kaddr = (char *)page_address(page);
p = kaddr+offset;
limit = kaddr + minix_last_byte(inode, n) - chunk_size;
for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
const char *name;
__u32 inumber;
if (sbi->s_version == MINIX_V3) {
minix3_dirent *de3 = (minix3_dirent *)p;
name = de3->name;
inumber = de3->inode;
} else {
minix_dirent *de = (minix_dirent *)p;
name = de->name;
inumber = de->inode;
}
if (inumber) {
unsigned l = strnlen(name, sbi->s_namelen);
if (!dir_emit(ctx, name, l,
inumber, DT_UNKNOWN)) {
dir_put_page(page);
return 0;
}
}
ctx->pos += chunk_size;
}
dir_put_page(page);
}
return 0;
}
static inline int namecompare(int len, int maxlen,
const char * name, const char * buffer)
{
if (len < maxlen && buffer[len])
return 0;
return !memcmp(name, buffer, len);
}
/*
* minix_find_entry()
*
* finds an entry in the specified directory with the wanted name. It
* returns the cache buffer in which the entry was found, and the entry
* itself (as a parameter - res_dir). It does NOT read the inode of the
* entry - you'll have to do that yourself if you want to.
*/
minix_dirent *minix_find_entry(struct dentry *dentry, struct page **res_page)
{
const char * name = dentry->d_name.name;
int namelen = dentry->d_name.len;
struct inode * dir = d_inode(dentry->d_parent);
struct super_block * sb = dir->i_sb;
struct minix_sb_info * sbi = minix_sb(sb);
unsigned long n;
unsigned long npages = dir_pages(dir);
struct page *page = NULL;
char *p;
char *namx;
__u32 inumber;
*res_page = NULL;
for (n = 0; n < npages; n++) {
char *kaddr, *limit;
page = dir_get_page(dir, n);
if (IS_ERR(page))
continue;
kaddr = (char*)page_address(page);
limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
if (sbi->s_version == MINIX_V3) {
minix3_dirent *de3 = (minix3_dirent *)p;
namx = de3->name;
inumber = de3->inode;
} else {
minix_dirent *de = (minix_dirent *)p;
namx = de->name;
inumber = de->inode;
}
if (!inumber)
continue;
if (namecompare(namelen, sbi->s_namelen, name, namx))
goto found;
}
dir_put_page(page);
}
return NULL;
found:
*res_page = page;
return (minix_dirent *)p;
}
int minix_add_link(struct dentry *dentry, struct inode *inode)
{
struct inode *dir = d_inode(dentry->d_parent);
const char * name = dentry->d_name.name;
int namelen = dentry->d_name.len;
struct super_block * sb = dir->i_sb;
struct minix_sb_info * sbi = minix_sb(sb);
struct page *page = NULL;
unsigned long npages = dir_pages(dir);
unsigned long n;
char *kaddr, *p;
minix_dirent *de;
minix3_dirent *de3;
loff_t pos;
int err;
char *namx = NULL;
__u32 inumber;
/*
* We take care of directory expansion in the same loop
* This code plays outside i_size, so it locks the page
* to protect that region.
*/
for (n = 0; n <= npages; n++) {
char *limit, *dir_end;
page = dir_get_page(dir, n);
err = PTR_ERR(page);
if (IS_ERR(page))
goto out;
lock_page(page);
kaddr = (char*)page_address(page);
dir_end = kaddr + minix_last_byte(dir, n);
limit = kaddr + PAGE_SIZE - sbi->s_dirsize;
for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
de = (minix_dirent *)p;
de3 = (minix3_dirent *)p;
if (sbi->s_version == MINIX_V3) {
namx = de3->name;
inumber = de3->inode;
} else {
namx = de->name;
inumber = de->inode;
}
if (p == dir_end) {
/* We hit i_size */
if (sbi->s_version == MINIX_V3)
de3->inode = 0;
else
de->inode = 0;
goto got_it;
}
if (!inumber)
goto got_it;
err = -EEXIST;
if (namecompare(namelen, sbi->s_namelen, name, namx))
goto out_unlock;
}
unlock_page(page);
dir_put_page(page);
}
BUG();
return -EINVAL;
got_it:
pos = page_offset(page) + p - (char *)page_address(page);
err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
if (err)
goto out_unlock;
memcpy (namx, name, namelen);
if (sbi->s_version == MINIX_V3) {
memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
de3->inode = inode->i_ino;
} else {
memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
de->inode = inode->i_ino;
}
err = dir_commit_chunk(page, pos, sbi->s_dirsize);
dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(dir);
out_put:
dir_put_page(page);
out:
return err;
out_unlock:
unlock_page(page);
goto out_put;
}
int minix_delete_entry(struct minix_dir_entry *de, struct page *page)
{
struct inode *inode = page->mapping->host;
char *kaddr = page_address(page);
loff_t pos = page_offset(page) + (char*)de - kaddr;
struct minix_sb_info *sbi = minix_sb(inode->i_sb);
unsigned len = sbi->s_dirsize;
int err;
lock_page(page);
err = minix_prepare_chunk(page, pos, len);
if (err == 0) {
if (sbi->s_version == MINIX_V3)
((minix3_dirent *) de)->inode = 0;
else
de->inode = 0;
err = dir_commit_chunk(page, pos, len);
} else {
unlock_page(page);
}
dir_put_page(page);
inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
return err;
}
int minix_make_empty(struct inode *inode, struct inode *dir)
{
struct page *page = grab_cache_page(inode->i_mapping, 0);
struct minix_sb_info *sbi = minix_sb(inode->i_sb);
char *kaddr;
int err;
if (!page)
return -ENOMEM;
err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
if (err) {
unlock_page(page);
goto fail;
}
kaddr = kmap_atomic(page);
memset(kaddr, 0, PAGE_SIZE);
if (sbi->s_version == MINIX_V3) {
minix3_dirent *de3 = (minix3_dirent *)kaddr;
de3->inode = inode->i_ino;
strcpy(de3->name, ".");
de3 = minix_next_entry(de3, sbi);
de3->inode = dir->i_ino;
strcpy(de3->name, "..");
} else {
minix_dirent *de = (minix_dirent *)kaddr;
de->inode = inode->i_ino;
strcpy(de->name, ".");
de = minix_next_entry(de, sbi);
de->inode = dir->i_ino;
strcpy(de->name, "..");
}
kunmap_atomic(kaddr);
err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
fail:
put_page(page);
return err;
}
/*
* routine to check that the specified directory is empty (for rmdir)
*/
int minix_empty_dir(struct inode * inode)
{
struct page *page = NULL;
unsigned long i, npages = dir_pages(inode);
struct minix_sb_info *sbi = minix_sb(inode->i_sb);
char *name;
__u32 inumber;
for (i = 0; i < npages; i++) {
char *p, *kaddr, *limit;
page = dir_get_page(inode, i);
if (IS_ERR(page))
continue;
kaddr = (char *)page_address(page);
limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
if (sbi->s_version == MINIX_V3) {
minix3_dirent *de3 = (minix3_dirent *)p;
name = de3->name;
inumber = de3->inode;
} else {
minix_dirent *de = (minix_dirent *)p;
name = de->name;
inumber = de->inode;
}
if (inumber != 0) {
/* check for . and .. */
if (name[0] != '.')
goto not_empty;
if (!name[1]) {
if (inumber != inode->i_ino)
goto not_empty;
} else if (name[1] != '.')
goto not_empty;
else if (name[2])
goto not_empty;
}
}
dir_put_page(page);
}
return 1;
not_empty:
dir_put_page(page);
return 0;
}
/* Releases the page */
void minix_set_link(struct minix_dir_entry *de, struct page *page,
struct inode *inode)
{
struct inode *dir = page->mapping->host;
struct minix_sb_info *sbi = minix_sb(dir->i_sb);
loff_t pos = page_offset(page) +
(char *)de-(char*)page_address(page);
int err;
lock_page(page);
err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
if (err == 0) {
if (sbi->s_version == MINIX_V3)
((minix3_dirent *) de)->inode = inode->i_ino;
else
de->inode = inode->i_ino;
err = dir_commit_chunk(page, pos, sbi->s_dirsize);
} else {
unlock_page(page);
}
dir_put_page(page);
dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(dir);
}
struct minix_dir_entry * minix_dotdot (struct inode *dir, struct page **p)
{
struct page *page = dir_get_page(dir, 0);
struct minix_sb_info *sbi = minix_sb(dir->i_sb);
struct minix_dir_entry *de = NULL;
if (!IS_ERR(page)) {
de = minix_next_entry(page_address(page), sbi);
*p = page;
}
return de;
}
ino_t minix_inode_by_name(struct dentry *dentry)
{
struct page *page;
struct minix_dir_entry *de = minix_find_entry(dentry, &page);
ino_t res = 0;
if (de) {
struct address_space *mapping = page->mapping;
struct inode *inode = mapping->host;
struct minix_sb_info *sbi = minix_sb(inode->i_sb);
if (sbi->s_version == MINIX_V3)
res = ((minix3_dirent *) de)->inode;
else
res = de->inode;
dir_put_page(page);
}
return res;
}
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