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-rw-r--r--fs/squashfs/Kconfig28
-rw-r--r--fs/squashfs/Makefile4
-rw-r--r--fs/squashfs/file_direct.c173
-rw-r--r--fs/squashfs/page_actor.c100
-rw-r--r--fs/squashfs/page_actor.h32
5 files changed, 336 insertions, 1 deletions
diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
index 159bd6676dc2..b6fa8657dcbc 100644
--- a/fs/squashfs/Kconfig
+++ b/fs/squashfs/Kconfig
@@ -26,6 +26,34 @@ config SQUASHFS
If unsure, say N.
choice
+ prompt "File decompression options"
+ depends on SQUASHFS
+ help
+ Squashfs now supports two options for decompressing file
+ data. Traditionally Squashfs has decompressed into an
+ intermediate buffer and then memcopied it into the page cache.
+ Squashfs now supports the ability to decompress directly into
+ the page cache.
+
+ If unsure, select "Decompress file data into an intermediate buffer"
+
+config SQUASHFS_FILE_CACHE
+ bool "Decompress file data into an intermediate buffer"
+ help
+ Decompress file data into an intermediate buffer and then
+ memcopy it into the page cache.
+
+config SQUASHFS_FILE_DIRECT
+ bool "Decompress files directly into the page cache"
+ help
+ Directly decompress file data into the page cache.
+ Doing so can significantly improve performance because
+ it eliminates a memcpy and it also removes the lock contention
+ on the single buffer.
+
+endchoice
+
+choice
prompt "Decompressor parallelisation options"
depends on SQUASHFS
help
diff --git a/fs/squashfs/Makefile b/fs/squashfs/Makefile
index e01ba1126c89..4132520b4ff2 100644
--- a/fs/squashfs/Makefile
+++ b/fs/squashfs/Makefile
@@ -4,7 +4,9 @@
obj-$(CONFIG_SQUASHFS) += squashfs.o
squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
-squashfs-y += namei.o super.o symlink.o decompressor.o file_cache.o
+squashfs-y += namei.o super.o symlink.o decompressor.o
+squashfs-$(CONFIG_SQUASHFS_FILE_CACHE) += file_cache.o
+squashfs-$(CONFIG_SQUASHFS_FILE_DIRECT) += file_direct.o page_actor.o
squashfs-$(CONFIG_SQUASHFS_DECOMP_SINGLE) += decompressor_single.o
squashfs-$(CONFIG_SQUASHFS_DECOMP_MULTI) += decompressor_multi.o
squashfs-$(CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU) += decompressor_multi_percpu.o
diff --git a/fs/squashfs/file_direct.c b/fs/squashfs/file_direct.c
new file mode 100644
index 000000000000..2943b2bfae48
--- /dev/null
+++ b/fs/squashfs/file_direct.c
@@ -0,0 +1,173 @@
+/*
+ * Copyright (c) 2013
+ * Phillip Lougher <phillip@squashfs.org.uk>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/pagemap.h>
+#include <linux/mutex.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+#include "page_actor.h"
+
+static int squashfs_read_cache(struct page *target_page, u64 block, int bsize,
+ int pages, struct page **page);
+
+/* Read separately compressed datablock directly into page cache */
+int squashfs_readpage_block(struct page *target_page, u64 block, int bsize)
+
+{
+ struct inode *inode = target_page->mapping->host;
+ struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
+
+ int file_end = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
+ int mask = (1 << (msblk->block_log - PAGE_CACHE_SHIFT)) - 1;
+ int start_index = target_page->index & ~mask;
+ int end_index = start_index | mask;
+ int i, n, pages, missing_pages, bytes, res = -ENOMEM;
+ struct page **page;
+ struct squashfs_page_actor *actor;
+ void *pageaddr;
+
+ if (end_index > file_end)
+ end_index = file_end;
+
+ pages = end_index - start_index + 1;
+
+ page = kmalloc(sizeof(void *) * pages, GFP_KERNEL);
+ if (page == NULL)
+ return res;
+
+ /*
+ * Create a "page actor" which will kmap and kunmap the
+ * page cache pages appropriately within the decompressor
+ */
+ actor = squashfs_page_actor_init_special(page, pages, 0);
+ if (actor == NULL)
+ goto out;
+
+ /* Try to grab all the pages covered by the Squashfs block */
+ for (missing_pages = 0, i = 0, n = start_index; i < pages; i++, n++) {
+ page[i] = (n == target_page->index) ? target_page :
+ grab_cache_page_nowait(target_page->mapping, n);
+
+ if (page[i] == NULL) {
+ missing_pages++;
+ continue;
+ }
+
+ if (PageUptodate(page[i])) {
+ unlock_page(page[i]);
+ page_cache_release(page[i]);
+ page[i] = NULL;
+ missing_pages++;
+ }
+ }
+
+ if (missing_pages) {
+ /*
+ * Couldn't get one or more pages, this page has either
+ * been VM reclaimed, but others are still in the page cache
+ * and uptodate, or we're racing with another thread in
+ * squashfs_readpage also trying to grab them. Fall back to
+ * using an intermediate buffer.
+ */
+ res = squashfs_read_cache(target_page, block, bsize, pages,
+ page);
+ goto out;
+ }
+
+ /* Decompress directly into the page cache buffers */
+ res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor);
+ if (res < 0)
+ goto mark_errored;
+
+ /* Last page may have trailing bytes not filled */
+ bytes = res % PAGE_CACHE_SIZE;
+ if (bytes) {
+ pageaddr = kmap_atomic(page[pages - 1]);
+ memset(pageaddr + bytes, 0, PAGE_CACHE_SIZE - bytes);
+ kunmap_atomic(pageaddr);
+ }
+
+ /* Mark pages as uptodate, unlock and release */
+ for (i = 0; i < pages; i++) {
+ flush_dcache_page(page[i]);
+ SetPageUptodate(page[i]);
+ unlock_page(page[i]);
+ if (page[i] != target_page)
+ page_cache_release(page[i]);
+ }
+
+ kfree(actor);
+ kfree(page);
+
+ return 0;
+
+mark_errored:
+ /* Decompression failed, mark pages as errored. Target_page is
+ * dealt with by the caller
+ */
+ for (i = 0; i < pages; i++) {
+ if (page[i] == target_page)
+ continue;
+ flush_dcache_page(page[i]);
+ SetPageError(page[i]);
+ unlock_page(page[i]);
+ page_cache_release(page[i]);
+ }
+
+out:
+ kfree(actor);
+ kfree(page);
+ return res;
+}
+
+
+static int squashfs_read_cache(struct page *target_page, u64 block, int bsize,
+ int pages, struct page **page)
+{
+ struct inode *i = target_page->mapping->host;
+ struct squashfs_cache_entry *buffer = squashfs_get_datablock(i->i_sb,
+ block, bsize);
+ int bytes = buffer->length, res = buffer->error, n, offset = 0;
+ void *pageaddr;
+
+ if (res) {
+ ERROR("Unable to read page, block %llx, size %x\n", block,
+ bsize);
+ goto out;
+ }
+
+ for (n = 0; n < pages && bytes > 0; n++,
+ bytes -= PAGE_CACHE_SIZE, offset += PAGE_CACHE_SIZE) {
+ int avail = min_t(int, bytes, PAGE_CACHE_SIZE);
+
+ if (page[n] == NULL)
+ continue;
+
+ pageaddr = kmap_atomic(page[n]);
+ squashfs_copy_data(pageaddr, buffer, offset, avail);
+ memset(pageaddr + avail, 0, PAGE_CACHE_SIZE - avail);
+ kunmap_atomic(pageaddr);
+ flush_dcache_page(page[n]);
+ SetPageUptodate(page[n]);
+ unlock_page(page[n]);
+ if (page[n] != target_page)
+ page_cache_release(page[n]);
+ }
+
+out:
+ squashfs_cache_put(buffer);
+ return res;
+}
diff --git a/fs/squashfs/page_actor.c b/fs/squashfs/page_actor.c
new file mode 100644
index 000000000000..5a1c11f56441
--- /dev/null
+++ b/fs/squashfs/page_actor.c
@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2013
+ * Phillip Lougher <phillip@squashfs.org.uk>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include "page_actor.h"
+
+/*
+ * This file contains implementations of page_actor for decompressing into
+ * an intermediate buffer, and for decompressing directly into the
+ * page cache.
+ *
+ * Calling code should avoid sleeping between calls to squashfs_first_page()
+ * and squashfs_finish_page().
+ */
+
+/* Implementation of page_actor for decompressing into intermediate buffer */
+static void *cache_first_page(struct squashfs_page_actor *actor)
+{
+ actor->next_page = 1;
+ return actor->buffer[0];
+}
+
+static void *cache_next_page(struct squashfs_page_actor *actor)
+{
+ if (actor->next_page == actor->pages)
+ return NULL;
+
+ return actor->buffer[actor->next_page++];
+}
+
+static void cache_finish_page(struct squashfs_page_actor *actor)
+{
+ /* empty */
+}
+
+struct squashfs_page_actor *squashfs_page_actor_init(void **buffer,
+ int pages, int length)
+{
+ struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL);
+
+ if (actor == NULL)
+ return NULL;
+
+ actor->length = length ? : pages * PAGE_CACHE_SIZE;
+ actor->buffer = buffer;
+ actor->pages = pages;
+ actor->next_page = 0;
+ actor->squashfs_first_page = cache_first_page;
+ actor->squashfs_next_page = cache_next_page;
+ actor->squashfs_finish_page = cache_finish_page;
+ return actor;
+}
+
+/* Implementation of page_actor for decompressing directly into page cache. */
+static void *direct_first_page(struct squashfs_page_actor *actor)
+{
+ actor->next_page = 1;
+ return actor->pageaddr = kmap_atomic(actor->page[0]);
+}
+
+static void *direct_next_page(struct squashfs_page_actor *actor)
+{
+ if (actor->pageaddr)
+ kunmap_atomic(actor->pageaddr);
+
+ return actor->pageaddr = actor->next_page == actor->pages ? NULL :
+ kmap_atomic(actor->page[actor->next_page++]);
+}
+
+static void direct_finish_page(struct squashfs_page_actor *actor)
+{
+ if (actor->pageaddr)
+ kunmap_atomic(actor->pageaddr);
+}
+
+struct squashfs_page_actor *squashfs_page_actor_init_special(struct page **page,
+ int pages, int length)
+{
+ struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL);
+
+ if (actor == NULL)
+ return NULL;
+
+ actor->length = length ? : pages * PAGE_CACHE_SIZE;
+ actor->page = page;
+ actor->pages = pages;
+ actor->next_page = 0;
+ actor->pageaddr = NULL;
+ actor->squashfs_first_page = direct_first_page;
+ actor->squashfs_next_page = direct_next_page;
+ actor->squashfs_finish_page = direct_finish_page;
+ return actor;
+}
diff --git a/fs/squashfs/page_actor.h b/fs/squashfs/page_actor.h
index 5b0ba5a7133a..26dd82008b82 100644
--- a/fs/squashfs/page_actor.h
+++ b/fs/squashfs/page_actor.h
@@ -8,6 +8,7 @@
* the COPYING file in the top-level directory.
*/
+#ifndef CONFIG_SQUASHFS_FILE_DIRECT
struct squashfs_page_actor {
void **page;
int pages;
@@ -46,4 +47,35 @@ static inline void squashfs_finish_page(struct squashfs_page_actor *actor)
{
/* empty */
}
+#else
+struct squashfs_page_actor {
+ union {
+ void **buffer;
+ struct page **page;
+ };
+ void *pageaddr;
+ void *(*squashfs_first_page)(struct squashfs_page_actor *);
+ void *(*squashfs_next_page)(struct squashfs_page_actor *);
+ void (*squashfs_finish_page)(struct squashfs_page_actor *);
+ int pages;
+ int length;
+ int next_page;
+};
+
+extern struct squashfs_page_actor *squashfs_page_actor_init(void **, int, int);
+extern struct squashfs_page_actor *squashfs_page_actor_init_special(struct page
+ **, int, int);
+static inline void *squashfs_first_page(struct squashfs_page_actor *actor)
+{
+ return actor->squashfs_first_page(actor);
+}
+static inline void *squashfs_next_page(struct squashfs_page_actor *actor)
+{
+ return actor->squashfs_next_page(actor);
+}
+static inline void squashfs_finish_page(struct squashfs_page_actor *actor)
+{
+ actor->squashfs_finish_page(actor);
+}
+#endif
#endif
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-11 15:36:55 +0100