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mm: make read_cache_page synchronous 

Ensure pages are uptodate after returning from read_cache_page, which allows
us to cut out most of the filesystem-internal PageUptodate calls.

I didn't have a great look down the call chains, but this appears to fixes 7
possible use-before uptodate in hfs, 2 in hfsplus, 1 in jfs, a few in
ecryptfs, 1 in jffs2, and a possible cleared data overwritten with readpage in
block2mtd.  All depending on whether the filler is async and/or can return
with a !uptodate page.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Nick Piggin 2007-05-06 14:49:04 -07:00 committed by Linus Torvalds
parent 714b8171af
commit 6fe6900e1e
24 changed files with 71 additions and 146 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/mtd/devices/block2mtd.c
View File

@ -42,11 +42,9 @@ static LIST_HEAD(blkmtd_device_list);
static struct page *page_read(struct address_space *mapping, int index)
{
filler_t *filler = (filler_t*)mapping->a_ops->readpage;
return read_cache_page(mapping, index, filler, NULL);
return read_mapping_page(mapping, index, NULL);
}
/* erase a specified part of the device */
static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len)
{

3
fs/afs/dir.c
View File

@ -194,10 +194,7 @@ static struct page *afs_dir_get_page(struct inode *dir, unsigned long index,
page = read_mapping_page(dir->i_mapping, index, &file);
if (!IS_ERR(page)) {
wait_on_page_locked(page);
kmap(page);
if (!PageUptodate(page))
goto fail;
if (!PageChecked(page))
afs_dir_check_page(dir, page);
if (PageError(page))

11
fs/afs/mntpt.c
View File

@ -68,13 +68,11 @@ int afs_mntpt_check_symlink(struct afs_vnode *vnode, struct key *key)
}
ret = -EIO;
wait_on_page_locked(page);
buf = kmap(page);
if (!PageUptodate(page))
goto out_free;
if (PageError(page))
goto out_free;
buf = kmap(page);
/* examine the symlink's contents */
size = vnode->status.size;
_debug("symlink to %*.*s", (int) size, (int) size, buf);
@ -91,8 +89,8 @@ int afs_mntpt_check_symlink(struct afs_vnode *vnode, struct key *key)
ret = 0;
out_free:
kunmap(page);
out_free:
page_cache_release(page);
out:
_leave(" = %d", ret);
@ -171,8 +169,7 @@ static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt)
}
ret = -EIO;
wait_on_page_locked(page);
if (!PageUptodate(page) || PageError(page))
if (PageError(page))
goto error;
buf = kmap(page);

3
fs/cramfs/inode.c
View File

@ -180,7 +180,8 @@ static void *cramfs_read(struct super_block *sb, unsigned int offset, unsigned i
struct page *page = NULL;
if (blocknr + i < devsize) {
page = read_mapping_page(mapping, blocknr + i, NULL);
page = read_mapping_page_async(mapping, blocknr + i,
NULL);
/* synchronous error? */
if (IS_ERR(page))
page = NULL;

11
fs/ecryptfs/mmap.c
View File

@ -46,7 +46,6 @@ struct kmem_cache *ecryptfs_lower_page_cache;
*/
static struct page *ecryptfs_get1page(struct file *file, int index)
{
struct page *page;
struct dentry *dentry;
struct inode *inode;
struct address_space *mapping;
@ -54,14 +53,7 @@ static struct page *ecryptfs_get1page(struct file *file, int index)
dentry = file->f_path.dentry;
inode = dentry->d_inode;
mapping = inode->i_mapping;
page = read_cache_page(mapping, index,
(filler_t *)mapping->a_ops->readpage,
(void *)file);
if (IS_ERR(page))
goto out;
wait_on_page_locked(page);
out:
return page;
return read_mapping_page(mapping, index, (void *)file);
}
static
@ -233,7 +225,6 @@ int ecryptfs_do_readpage(struct file *file, struct page *page,
ecryptfs_printk(KERN_ERR, "Error reading from page cache\n");
goto out;
}
wait_on_page_locked(lower_page);
page_data = kmap_atomic(page, KM_USER0);
lower_page_data = kmap_atomic(lower_page, KM_USER1);
memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE);

3
fs/ext2/dir.c
View File

@ -161,10 +161,7 @@ static struct page * ext2_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)) {
wait_on_page_locked(page);
kmap(page);
if (!PageUptodate(page))
goto fail;
if (!PageChecked(page))
ext2_check_page(page);
if (PageError(page))

3
fs/freevxfs/vxfs_subr.c
View File

@ -74,10 +74,7 @@ vxfs_get_page(struct address_space *mapping, u_long n)
pp = read_mapping_page(mapping, n, NULL);
if (!IS_ERR(pp)) {
wait_on_page_locked(pp);
kmap(pp);
if (!PageUptodate(pp))
goto fail;
/** if (!PageChecked(pp)) **/
/** vxfs_check_page(pp); **/
if (PageError(pp))

1
fs/minix/dir.c
View File

@ -65,7 +65,6 @@ 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)) {
wait_on_page_locked(page);
kmap(page);
if (!PageUptodate(page))
goto fail;

12
fs/namei.c
View File

@ -2671,19 +2671,9 @@ static char *page_getlink(struct dentry * dentry, struct page **ppage)
struct address_space *mapping = dentry->d_inode->i_mapping;
page = read_mapping_page(mapping, 0, NULL);
if (IS_ERR(page))
goto sync_fail;
wait_on_page_locked(page);
if (!PageUptodate(page))
goto async_fail;
return (char*)page;
*ppage = page;
return kmap(page);
async_fail:
page_cache_release(page);
return ERR_PTR(-EIO);
sync_fail:
return (char*)page;
}
int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)

5
fs/nfs/dir.c
View File

@ -334,8 +334,6 @@ int find_dirent_page(nfs_readdir_descriptor_t *desc)
status = PTR_ERR(page);
goto out;
}
if (!PageUptodate(page))
goto read_error;
/* NOTE: Someone else may have changed the READDIRPLUS flag */
desc->page = page;
@ -349,9 +347,6 @@ int find_dirent_page(nfs_readdir_descriptor_t *desc)
out:
dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __FUNCTION__, status);
return status;
read_error:
page_cache_release(page);
return -EIO;
}
/*

6
fs/nfs/symlink.c
View File

@ -61,15 +61,9 @@ static void *nfs_follow_link(struct dentry *dentry, struct nameidata *nd)
err = page;
goto read_failed;
}
if (!PageUptodate(page)) {
err = ERR_PTR(-EIO);
goto getlink_read_error;
}
nd_set_link(nd, kmap(page));
return page;
getlink_read_error:
page_cache_release(page);
read_failed:
nd_set_link(nd, err);
return NULL;

3
fs/ntfs/aops.h
View File

@ -89,9 +89,8 @@ static inline struct page *ntfs_map_page(struct address_space *mapping,
struct page *page = read_mapping_page(mapping, index, NULL);
if (!IS_ERR(page)) {
wait_on_page_locked(page);
kmap(page);
if (PageUptodate(page) && !PageError(page))
if (!PageError(page))
return page;
ntfs_unmap_page(page);
return ERR_PTR(-EIO);

18
fs/ntfs/attrib.c
View File

@ -2532,14 +2532,7 @@ int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt, const u8 val)
page = read_mapping_page(mapping, idx, NULL);
if (IS_ERR(page)) {
ntfs_error(vol->sb, "Failed to read first partial "
"page (sync error, index 0x%lx).", idx);
return PTR_ERR(page);
}
wait_on_page_locked(page);
if (unlikely(!PageUptodate(page))) {
ntfs_error(vol->sb, "Failed to read first partial page "
"(async error, index 0x%lx).", idx);
page_cache_release(page);
"page (error, index 0x%lx).", idx);
return PTR_ERR(page);
}
/*
@ -2602,14 +2595,7 @@ int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt, const u8 val)
page = read_mapping_page(mapping, idx, NULL);
if (IS_ERR(page)) {
ntfs_error(vol->sb, "Failed to read last partial page "
"(sync error, index 0x%lx).", idx);
return PTR_ERR(page);
}
wait_on_page_locked(page);
if (unlikely(!PageUptodate(page))) {
ntfs_error(vol->sb, "Failed to read last partial page "
"(async error, index 0x%lx).", idx);
page_cache_release(page);
"(error, index 0x%lx).", idx);
return PTR_ERR(page);
}
kaddr = kmap_atomic(page, KM_USER0);

3
fs/ntfs/file.c
View File

@ -236,8 +236,7 @@ do_non_resident_extend:
err = PTR_ERR(page);
goto init_err_out;
}
wait_on_page_locked(page);
if (unlikely(!PageUptodate(page) || PageError(page))) {
if (unlikely(PageError(page))) {
page_cache_release(page);
err = -EIO;
goto init_err_out;

30
fs/ntfs/super.c
View File

@ -2471,7 +2471,6 @@ static s64 get_nr_free_clusters(ntfs_volume *vol)
s64 nr_free = vol->nr_clusters;
u32 *kaddr;
struct address_space *mapping = vol->lcnbmp_ino->i_mapping;
filler_t *readpage = (filler_t*)mapping->a_ops->readpage;
struct page *page;
pgoff_t index, max_index;
@ -2494,24 +2493,14 @@ static s64 get_nr_free_clusters(ntfs_volume *vol)
* Read the page from page cache, getting it from backing store
* if necessary, and increment the use count.
*/
page = read_cache_page(mapping, index, (filler_t*)readpage,
NULL);
page = read_mapping_page(mapping, index, NULL);
/* Ignore pages which errored synchronously. */
if (IS_ERR(page)) {
ntfs_debug("Sync read_cache_page() error. Skipping "
ntfs_debug("read_mapping_page() error. Skipping "
"page (index 0x%lx).", index);
nr_free -= PAGE_CACHE_SIZE * 8;
continue;
}
wait_on_page_locked(page);
/* Ignore pages which errored asynchronously. */
if (!PageUptodate(page)) {
ntfs_debug("Async read_cache_page() error. Skipping "
"page (index 0x%lx).", index);
page_cache_release(page);
nr_free -= PAGE_CACHE_SIZE * 8;
continue;
}
kaddr = (u32*)kmap_atomic(page, KM_USER0);
/*
* For each 4 bytes, subtract the number of set bits. If this
@ -2562,7 +2551,6 @@ static unsigned long __get_nr_free_mft_records(ntfs_volume *vol,
{
u32 *kaddr;
struct address_space *mapping = vol->mftbmp_ino->i_mapping;
filler_t *readpage = (filler_t*)mapping->a_ops->readpage;
struct page *page;
pgoff_t index;
@ -2576,24 +2564,14 @@ static unsigned long __get_nr_free_mft_records(ntfs_volume *vol,
* Read the page from page cache, getting it from backing store
* if necessary, and increment the use count.
*/
page = read_cache_page(mapping, index, (filler_t*)readpage,
NULL);
page = read_mapping_page(mapping, index, NULL);
/* Ignore pages which errored synchronously. */
if (IS_ERR(page)) {
ntfs_debug("Sync read_cache_page() error. Skipping "
ntfs_debug("read_mapping_page() error. Skipping "
"page (index 0x%lx).", index);
nr_free -= PAGE_CACHE_SIZE * 8;
continue;
}
wait_on_page_locked(page);
/* Ignore pages which errored asynchronously. */
if (!PageUptodate(page)) {
ntfs_debug("Async read_cache_page() error. Skipping "
"page (index 0x%lx).", index);
page_cache_release(page);
nr_free -= PAGE_CACHE_SIZE * 8;
continue;
}
kaddr = (u32*)kmap_atomic(page, KM_USER0);
/*
* For each 4 bytes, subtract the number of set bits. If this

7
fs/ocfs2/symlink.c
View File

@ -67,16 +67,9 @@ static char *ocfs2_page_getlink(struct dentry * dentry,
page = read_mapping_page(mapping, 0, NULL);
if (IS_ERR(page))
goto sync_fail;
wait_on_page_locked(page);
if (!PageUptodate(page))
goto async_fail;
*ppage = page;
return kmap(page);
async_fail:
page_cache_release(page);
return ERR_PTR(-EIO);
sync_fail:
return (char*)page;
}

3
fs/partitions/check.c
View File

@ -569,9 +569,6 @@ unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
NULL);
if (!IS_ERR(page)) {
wait_on_page_locked(page);
if (!PageUptodate(page))
goto fail;
if (PageError(page))
goto fail;
p->v = page;

4
fs/reiserfs/xattr.c
View File

@ -410,11 +410,7 @@ static struct page *reiserfs_get_page(struct inode *dir, unsigned long n)
mapping_set_gfp_mask(mapping, GFP_NOFS);
page = read_mapping_page(mapping, n, NULL);
if (!IS_ERR(page)) {
wait_on_page_locked(page);
kmap(page);
if (!PageUptodate(page))
goto fail;
if (PageError(page))
goto fail;
}

10
fs/sysv/dir.c
View File

@ -54,17 +54,9 @@ 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)) {
wait_on_page_locked(page);
if (!IS_ERR(page))
kmap(page);
if (!PageUptodate(page))
goto fail;
}
return page;
fail:
dir_put_page(page);
return ERR_PTR(-EIO);
}
static int sysv_readdir(struct file * filp, void * dirent, filldir_t filldir)

6
fs/ufs/dir.c
View File

@ -180,13 +180,9 @@ fail:
static struct page *ufs_get_page(struct inode *dir, unsigned long n)
{
struct address_space *mapping = dir->i_mapping;
struct page *page = read_cache_page(mapping, n,
(filler_t*)mapping->a_ops->readpage, NULL);
struct page *page = read_mapping_page(mapping, n, NULL);
if (!IS_ERR(page)) {
wait_on_page_locked(page);
kmap(page);
if (!PageUptodate(page))
goto fail;
if (!PageChecked(page))
ufs_check_page(page);
if (PageError(page))

6
fs/ufs/util.c
View File

@ -251,13 +251,11 @@ struct page *ufs_get_locked_page(struct address_space *mapping,
page = find_lock_page(mapping, index);
if (!page) {
page = read_cache_page(mapping, index,
(filler_t*)mapping->a_ops->readpage,
NULL);
page = read_mapping_page(mapping, index, NULL);
if (IS_ERR(page)) {
printk(KERN_ERR "ufs_change_blocknr: "
"read_cache_page error: ino %lu, index: %lu\n",
"read_mapping_page error: ino %lu, index: %lu\n",
mapping->host->i_ino, index);
goto out;
}

11
include/linux/pagemap.h
View File

@ -95,12 +95,23 @@ static inline struct page *grab_cache_page(struct address_space *mapping, unsign
extern struct page * grab_cache_page_nowait(struct address_space *mapping,
unsigned long index);
extern struct page * read_cache_page_async(struct address_space *mapping,
unsigned long index, filler_t *filler,
void *data);
extern struct page * read_cache_page(struct address_space *mapping,
unsigned long index, filler_t *filler,
void *data);
extern int read_cache_pages(struct address_space *mapping,
struct list_head *pages, filler_t *filler, void *data);
static inline struct page *read_mapping_page_async(
struct address_space *mapping,
unsigned long index, void *data)
{
filler_t *filler = (filler_t *)mapping->a_ops->readpage;
return read_cache_page_async(mapping, index, filler, data);
}
static inline struct page *read_mapping_page(struct address_space *mapping,
unsigned long index, void *data)
{

49
mm/filemap.c
View File

@ -1726,7 +1726,7 @@ int generic_file_readonly_mmap(struct file * file, struct vm_area_struct * vma)
EXPORT_SYMBOL(generic_file_mmap);
EXPORT_SYMBOL(generic_file_readonly_mmap);
static inline struct page *__read_cache_page(struct address_space *mapping,
static struct page *__read_cache_page(struct address_space *mapping,
unsigned long index,
int (*filler)(void *,struct page*),
void *data)
@ -1763,17 +1763,11 @@ repeat:
return page;
}
/**
* read_cache_page - read into page cache, fill it if needed
* @mapping: the page's address_space
* @index: the page index
* @filler: function to perform the read
* @data: destination for read data
*
* Read into the page cache. If a page already exists,
* and PageUptodate() is not set, try to fill the page.
/*
* Same as read_cache_page, but don't wait for page to become unlocked
* after submitting it to the filler.
*/
struct page *read_cache_page(struct address_space *mapping,
struct page *read_cache_page_async(struct address_space *mapping,
unsigned long index,
int (*filler)(void *,struct page*),
void *data)
@ -1804,6 +1798,39 @@ retry:
page_cache_release(page);
page = ERR_PTR(err);
}
out:
mark_page_accessed(page);
return page;
}
EXPORT_SYMBOL(read_cache_page_async);
/**
* read_cache_page - read into page cache, fill it if needed
* @mapping: the page's address_space
* @index: the page index
* @filler: function to perform the read
* @data: destination for read data
*
* Read into the page cache. If a page already exists, and PageUptodate() is
* not set, try to fill the page then wait for it to become unlocked.
*
* If the page does not get brought uptodate, return -EIO.
*/
struct page *read_cache_page(struct address_space *mapping,
unsigned long index,
int (*filler)(void *,struct page*),
void *data)
{
struct page *page;
page = read_cache_page_async(mapping, index, filler, data);
if (IS_ERR(page))
goto out;
wait_on_page_locked(page);
if (!PageUptodate(page)) {
page_cache_release(page);
page = ERR_PTR(-EIO);
}
out:
return page;
}

3
mm/swapfile.c
View File

@ -1531,9 +1531,6 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
error = PTR_ERR(page);
goto bad_swap;
}
wait_on_page_locked(page);
if (!PageUptodate(page))
goto bad_swap;
kmap(page);
swap_header = page_address(page);