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: Anton Altaparmakov <aia21@cantab.net>
diff --git a/fs/ntfs/compress.c b/fs/ntfs/compress.c
index ee5ae70..6d265cf 100644
--- a/fs/ntfs/compress.c
+++ b/fs/ntfs/compress.c
@@ -96,13 +96,14 @@
/**
* 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 @@
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 @@
/**
* 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 @@
* @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 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 @@
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 @@
* 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 @@
*/
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 @@
* 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 @@
* 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 @@
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().