Commit 36763677 authored by Anton Altaparmakov's avatar Anton Altaparmakov
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NTFS: - In fs/ntfs/compress.c, use i_size_read() at the start and then use the


	cached value everywhere.  Cache the initialized_size in the same way
	and protect the critical region where the two sizes are read using the
	new size_lock of the ntfs inode.
      - Add the new size_lock to the ntfs_inode structure (fs/ntfs/inode.h)
	and initialize it (fs/ntfs/inode.c).
Signed-off-by: default avatarAnton Altaparmakov <aia21@cantab.net>
parent 899101ae
......@@ -34,6 +34,13 @@ ToDo/Notes:
- Use i_size_read() once and then use the cached value in
fs/ntfs/lcnalloc.c::ntfs_cluster_alloc().
- Use i_size_read() in fs/ntfs/file.c::ntfs_file_open().
- Add size_lock to the ntfs_inode structure. This is an rw spinlock
and it locks against access to the inode sizes. Note, ->size_lock
is also accessed from irq context so you must use the _irqsave and
_irqrestore lock and unlock functions, respectively.
- Use i_size_read() in fs/ntfs/compress.c at the start of the read and
use the cached value afterwards. Cache the initialized_size in the
same way and protect access to the two sizes using the size_lock.
2.1.22 - Many bug and race fixes and error handling improvements.
......
......@@ -96,13 +96,14 @@ void free_compression_buffers(void)
/**
* zero_partial_compressed_page - zero out of bounds compressed page region
*/
static void zero_partial_compressed_page(ntfs_inode *ni, struct page *page)
static void zero_partial_compressed_page(struct page *page,
const s64 initialized_size)
{
u8 *kp = page_address(page);
unsigned int kp_ofs;
ntfs_debug("Zeroing page region outside initialized size.");
if (((s64)page->index << PAGE_CACHE_SHIFT) >= ni->initialized_size) {
if (((s64)page->index << PAGE_CACHE_SHIFT) >= initialized_size) {
/*
* FIXME: Using clear_page() will become wrong when we get
* PAGE_CACHE_SIZE != PAGE_SIZE but for now there is no problem.
......@@ -110,7 +111,7 @@ static void zero_partial_compressed_page(ntfs_inode *ni, struct page *page)
clear_page(kp);
return;
}
kp_ofs = ni->initialized_size & ~PAGE_CACHE_MASK;
kp_ofs = initialized_size & ~PAGE_CACHE_MASK;
memset(kp + kp_ofs, 0, PAGE_CACHE_SIZE - kp_ofs);
return;
}
......@@ -118,12 +119,12 @@ static void zero_partial_compressed_page(ntfs_inode *ni, struct page *page)
/**
* handle_bounds_compressed_page - test for&handle out of bounds compressed page
*/
static inline void handle_bounds_compressed_page(ntfs_inode *ni,
struct page *page)
static inline void handle_bounds_compressed_page(struct page *page,
const loff_t i_size, const s64 initialized_size)
{
if ((page->index >= (ni->initialized_size >> PAGE_CACHE_SHIFT)) &&
(ni->initialized_size < VFS_I(ni)->i_size))
zero_partial_compressed_page(ni, page);
if ((page->index >= (initialized_size >> PAGE_CACHE_SHIFT)) &&
(initialized_size < i_size))
zero_partial_compressed_page(page, initialized_size);
return;
}
......@@ -138,6 +139,8 @@ static inline void handle_bounds_compressed_page(ntfs_inode *ni,
* @xpage_done: set to 1 if xpage was completed successfully (IN/OUT)
* @cb_start: compression block to decompress (IN)
* @cb_size: size of compression block @cb_start in bytes (IN)
* @i_size: file size when we started the read (IN)
* @initialized_size: initialized file size when we started the read (IN)
*
* The caller must have disabled preemption. ntfs_decompress() reenables it when
* the critical section is finished.
......@@ -165,7 +168,8 @@ static inline void handle_bounds_compressed_page(ntfs_inode *ni,
static int ntfs_decompress(struct page *dest_pages[], int *dest_index,
int *dest_ofs, const int dest_max_index, const int dest_max_ofs,
const int xpage, char *xpage_done, u8 *const cb_start,
const u32 cb_size)
const u32 cb_size, const loff_t i_size,
const s64 initialized_size)
{
/*
* Pointers into the compressed data, i.e. the compression block (cb),
......@@ -219,9 +223,6 @@ return_error:
spin_unlock(&ntfs_cb_lock);
/* Second stage: finalize completed pages. */
if (nr_completed_pages > 0) {
struct page *page = dest_pages[completed_pages[0]];
ntfs_inode *ni = NTFS_I(page->mapping->host);
for (i = 0; i < nr_completed_pages; i++) {
int di = completed_pages[i];
......@@ -230,7 +231,8 @@ return_error:
* If we are outside the initialized size, zero
* the out of bounds page range.
*/
handle_bounds_compressed_page(ni, dp);
handle_bounds_compressed_page(dp, i_size,
initialized_size);
flush_dcache_page(dp);
kunmap(dp);
SetPageUptodate(dp);
......@@ -478,12 +480,14 @@ return_overflow:
*/
int ntfs_read_compressed_block(struct page *page)
{
loff_t i_size;
s64 initialized_size;
struct address_space *mapping = page->mapping;
ntfs_inode *ni = NTFS_I(mapping->host);
ntfs_volume *vol = ni->vol;
struct super_block *sb = vol->sb;
runlist_element *rl;
unsigned long block_size = sb->s_blocksize;
unsigned long flags, block_size = sb->s_blocksize;
unsigned char block_size_bits = sb->s_blocksize_bits;
u8 *cb, *cb_pos, *cb_end;
struct buffer_head **bhs;
......@@ -552,8 +556,12 @@ int ntfs_read_compressed_block(struct page *page)
* The remaining pages need to be allocated and inserted into the page
* cache, alignment guarantees keep all the below much simpler. (-8
*/
max_page = ((VFS_I(ni)->i_size + PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT) - offset;
read_lock_irqsave(&ni->size_lock, flags);
i_size = i_size_read(VFS_I(ni));
initialized_size = ni->initialized_size;
read_unlock_irqrestore(&ni->size_lock, flags);
max_page = ((i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
offset;
if (nr_pages < max_page)
max_page = nr_pages;
for (i = 0; i < max_page; i++, offset++) {
......@@ -824,7 +832,8 @@ lock_retry_remap:
* If we are outside the initialized size, zero
* the out of bounds page range.
*/
handle_bounds_compressed_page(ni, page);
handle_bounds_compressed_page(page, i_size,
initialized_size);
flush_dcache_page(page);
kunmap(page);
SetPageUptodate(page);
......@@ -847,7 +856,8 @@ lock_retry_remap:
ntfs_debug("Found compressed compression block.");
err = ntfs_decompress(pages, &cur_page, &cur_ofs,
cb_max_page, cb_max_ofs, xpage, &xpage_done,
cb_pos, cb_size - (cb_pos - cb));
cb_pos, cb_size - (cb_pos - cb), i_size,
initialized_size);
/*
* We can sleep from now on, lock already dropped by
* ntfs_decompress().
......
......@@ -376,6 +376,7 @@ static void ntfs_destroy_extent_inode(ntfs_inode *ni)
void __ntfs_init_inode(struct super_block *sb, ntfs_inode *ni)
{
ntfs_debug("Entering.");
rwlock_init(&ni->size_lock);
ni->initialized_size = ni->allocated_size = 0;
ni->seq_no = 0;
atomic_set(&ni->count, 1);
......
......@@ -44,6 +44,7 @@ typedef struct _ntfs_inode ntfs_inode;
* fields already provided in the VFS inode.
*/
struct _ntfs_inode {
rwlock_t size_lock; /* Lock serializing access to inode sizes. */
s64 initialized_size; /* Copy from the attribute record. */
s64 allocated_size; /* Copy from the attribute record. */
unsigned long state; /* NTFS specific flags describing this inode.
......
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