Squashfs Whitelist and Compression Threshold

deleted file mode 100644
index f2310d2a2019..000000000000
@@ -1,38 +0,0 @@
-/*
- * Copyright (c) 2013
- * Phillip Lougher <[email protected]>
- *
- * 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"
-
-/* Read separately compressed datablock and memcopy into page cache */
-int squashfs_readpage_block(struct page *page, u64 block, int bsize)
-{
-	struct inode *i = page->mapping->host;
-	struct squashfs_cache_entry *buffer = squashfs_get_datablock(i->i_sb,
-		block, bsize);
-	int res = buffer->error;
-
-	if (res)
-		ERROR("Unable to read page, block %llx, size %x\n", block,
-			bsize);
-	else
-		squashfs_copy_cache(page, buffer, buffer->length, 0);
-
-	squashfs_cache_put(buffer);
-	return res;
-}

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index 23813c078cc9..05e42441d106 100644
@@ -209,17 +209,14 @@ void squashfs_cache_put(struct squashfs_cache_entry *entry)
  */
 void squashfs_cache_delete(struct squashfs_cache *cache)
 {
-	int i, j;
+	int i;
 
 	if (cache == NULL)
 		return;
 
 	for (i = 0; i < cache->entries; i++) {
-		if (cache->entry[i].data) {
-			for (j = 0; j < cache->pages; j++)
-				kfree(cache->entry[i].data[j]);
-			kfree(cache->entry[i].data);
-		}
+		if (cache->entry[i].page)
+			free_page_array(cache->entry[i].page, cache->pages);
 		kfree(cache->entry[i].actor);
 	}
 

@@ -236,7 +233,7 @@ void squashfs_cache_delete(struct squashfs_cache *cache)
 struct squashfs_cache *squashfs_cache_init(char *name, int entries,
 	int block_size)
 {
-	int i, j;
+	int i;
 	struct squashfs_cache *cache = kzalloc(sizeof(*cache), GFP_KERNEL);
 
 	if (cache == NULL) {

@@ -268,22 +265,13 @@ struct squashfs_cache *squashfs_cache_init(char *name, int entries,
 		init_waitqueue_head(&cache->entry[i].wait_queue);
 		entry->cache = cache;
 		entry->block = SQUASHFS_INVALID_BLK;
-		entry->data = kcalloc(cache->pages, sizeof(void *), GFP_KERNEL);
-		if (entry->data == NULL) {
+		entry->page = alloc_page_array(cache->pages, GFP_KERNEL);
+		if (!entry->page) {
 			ERROR("Failed to allocate %s cache entry\n", name);
 			goto cleanup;
 		}
-
-		for (j = 0; j < cache->pages; j++) {
-			entry->data[j] = kmalloc(PAGE_SIZE, GFP_KERNEL);
-			if (entry->data[j] == NULL) {
-				ERROR("Failed to allocate %s buffer\n", name);
-				goto cleanup;
-			}
-		}
-
-		entry->actor = squashfs_page_actor_init(entry->data,
-						cache->pages, 0);
+		entry->actor = squashfs_page_actor_init(entry->page,
+			cache->pages, 0, NULL);
 		if (entry->actor == NULL) {
 			ERROR("Failed to allocate %s cache entry\n", name);
 			goto cleanup;

@@ -314,18 +302,20 @@ int squashfs_copy_data(void *buffer, struct squashfs_cache_entry *entry,
 		return min(length, entry->length - offset);
 
 	while (offset < entry->length) {
-		void *buff = entry->data[offset / PAGE_SIZE]
-				+ (offset % PAGE_SIZE);
+		void *buff = kmap_atomic(entry->page[offset / PAGE_SIZE])
+			     + (offset % PAGE_SIZE);
 		int bytes = min_t(int, entry->length - offset,
 				PAGE_SIZE - (offset % PAGE_SIZE));
 
 		if (bytes >= remaining) {
 			memcpy(buffer, buff, remaining);
+			kunmap_atomic(buff);
 			remaining = 0;
 			break;
 		}
 
 		memcpy(buffer, buff, bytes);
+		kunmap_atomic(buff);
 		buffer += bytes;
 		remaining -= bytes;
 		offset += bytes;

@@ -416,43 +406,38 @@ struct squashfs_cache_entry *squashfs_get_datablock(struct super_block *sb,
 void *squashfs_read_table(struct super_block *sb, u64 block, int length)
 {
 	int pages = (length + PAGE_SIZE - 1) >> PAGE_SHIFT;
-	int i, res;
-	void *table, *buffer, **data;
+	struct page **page;
+	void *buff;
+	int res;
 	struct squashfs_page_actor *actor;
 
-	table = buffer = kmalloc(length, GFP_KERNEL);
-	if (table == NULL)
+	page = alloc_page_array(pages, GFP_KERNEL);
+	if (!page)
 		return ERR_PTR(-ENOMEM);
 
-	data = kcalloc(pages, sizeof(void *), GFP_KERNEL);
-	if (data == NULL) {
-		res = -ENOMEM;
-		goto failed;
-	}
-
-	actor = squashfs_page_actor_init(data, pages, length);
+	actor = squashfs_page_actor_init(page, pages, length, NULL);
 	if (actor == NULL) {
 		res = -ENOMEM;
-		goto failed2;
+		goto failed;
 	}
 
-	for (i = 0; i < pages; i++, buffer += PAGE_SIZE)
-		data[i] = buffer;
-
 	res = squashfs_read_data(sb, block, length |
 		SQUASHFS_COMPRESSED_BIT_BLOCK, NULL, actor);
 
-	kfree(data);
-	kfree(actor);
-
 	if (res < 0)
-		goto failed;
+		goto failed2;
 
-	return table;
+	buff = kmalloc(length, GFP_KERNEL);
+	if (!buff)
+		goto failed2;
+	squashfs_actor_to_buf(actor, buff, length);
+	squashfs_page_actor_free(actor, 0);
+	free_page_array(page, pages);
+	return buff;
 
 failed2:
-	kfree(data);
+	squashfs_page_actor_free(actor, 0);
 failed:
-	kfree(table);
+	free_page_array(page, pages);
 	return ERR_PTR(res);
 }

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index cb485d8e0e91..4642b869d931 100644
@@ -52,7 +52,7 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize)
 	 * 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);
+	actor = squashfs_page_actor_init(page, pages, 0, NULL);
 	if (actor == NULL)
 		goto out;
 

@@ -131,7 +131,7 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize)
 	}
 
 out:
-	kfree(actor);
+	squashfs_page_actor_free(actor, 0);
 	kfree(page);
 	return res;
 }

index 95da65366548..854d5ece7d08 100644
@@ -94,39 +94,18 @@ static int lz4_uncompress(struct squashfs_sb_info *msblk, void *strm,
 	struct buffer_head **bh, int b, int offset, int length,
 	struct squashfs_page_actor *output)
 {
+	int res;
 	struct squashfs_lz4 *stream = strm;
-	void *buff = stream->input, *data;
-	int avail, i, bytes = length, res;
-
-	for (i = 0; i < b; i++) {
-		avail = min(bytes, msblk->devblksize - offset);
-		memcpy(buff, bh[i]->b_data + offset, avail);
-		buff += avail;
-		bytes -= avail;
-		offset = 0;
-		put_bh(bh[i]);
-	}
 
+	squashfs_bh_to_buf(bh, b, stream->input, offset, length,
+		msblk->devblksize);
 	res = LZ4_decompress_safe(stream->input, stream->output,
 		length, output->length);
 
 	if (res < 0)
 		return -EIO;
 
-	bytes = res;
-	data = squashfs_first_page(output);
-	buff = stream->output;
-	while (data) {
-		if (bytes <= PAGE_SIZE) {
-			memcpy(data, buff, bytes);
-			break;
-		}
-		memcpy(data, buff, PAGE_SIZE);
-		buff += PAGE_SIZE;
-		bytes -= PAGE_SIZE;
-		data = squashfs_next_page(output);
-	}
-	squashfs_finish_page(output);
+	squashfs_buf_to_actor(stream->output, output, res);
 
 	return res;
 }

index 934c17e96590..2c844d53a59e 100644
@@ -79,45 +79,19 @@ static int lzo_uncompress(struct squashfs_sb_info *msblk, void *strm,
 	struct buffer_head **bh, int b, int offset, int length,
 	struct squashfs_page_actor *output)
 {
-	struct squashfs_lzo *stream = strm;
-	void *buff = stream->input, *data;
-	int avail, i, bytes = length, res;
+	int res;
 	size_t out_len = output->length;
+	struct squashfs_lzo *stream = strm;
 
-	for (i = 0; i < b; i++) {
-		avail = min(bytes, msblk->devblksize - offset);
-		memcpy(buff, bh[i]->b_data + offset, avail);
-		buff += avail;
-		bytes -= avail;
-		offset = 0;
-		put_bh(bh[i]);
-	}
-
+	squashfs_bh_to_buf(bh, b, stream->input, offset, length,
+		msblk->devblksize);
 	res = lzo1x_decompress_safe(stream->input, (size_t)length,
 					stream->output, &out_len);
 	if (res != LZO_E_OK)
-		goto failed;
+		return -EIO;
+	squashfs_buf_to_actor(stream->output, output, out_len);
 
-	res = bytes = (int)out_len;
-	data = squashfs_first_page(output);
-	buff = stream->output;
-	while (data) {
-		if (bytes <= PAGE_SIZE) {
-			memcpy(data, buff, bytes);
-			break;
-		} else {
-			memcpy(data, buff, PAGE_SIZE);
-			buff += PAGE_SIZE;
-			bytes -= PAGE_SIZE;
-			data = squashfs_next_page(output);
-		}
-	}
-	squashfs_finish_page(output);
-
-	return res;
-
-failed:
-	return -EIO;
+	return out_len;
 }
 
 const struct squashfs_decompressor squashfs_lzo_comp_ops = {

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75 lines not on this page · raw message

index 1da565cb50c3..8a6995de0277 100644
@@ -49,7 +49,7 @@ struct squashfs_cache_entry {
 	int			num_waiters;
 	wait_queue_head_t	wait_queue;
 	struct squashfs_cache	*cache;
-	void			**data;
+	struct page		**page;
 	struct squashfs_page_actor	*actor;
 };
 

index 6bfaef73d065..2f7be1fb167c 100644
@@ -55,7 +55,7 @@ static void *squashfs_xz_comp_opts(struct squashfs_sb_info *msblk,
 	struct comp_opts *opts;
 	int err = 0, n;
 
-	opts = kmalloc(sizeof(*opts), GFP_KERNEL);
+	opts = kmalloc(sizeof(*opts), GFP_ATOMIC);
 	if (opts == NULL) {
 		err = -ENOMEM;
 		goto out2;

@@ -136,6 +136,7 @@ static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm,
 	enum xz_ret xz_err;
 	int avail, total = 0, k = 0;
 	struct squashfs_xz *stream = strm;
+	void *buf = NULL;
 
 	xz_dec_reset(stream->state);
 	stream->buf.in_pos = 0;

@@ -156,12 +157,20 @@ static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm,
 
 		if (stream->buf.out_pos == stream->buf.out_size) {
 			stream->buf.out = squashfs_next_page(output);
-			if (stream->buf.out != NULL) {
+			if (!IS_ERR(stream->buf.out)) {
 				stream->buf.out_pos = 0;
 				total += PAGE_SIZE;
 			}
 		}
 
+		if (!stream->buf.out) {
+			if (!buf) {
+				buf = kmalloc(PAGE_SIZE, GFP_ATOMIC);
+				if (!buf)
+					goto out;
+			}
+			stream->buf.out = buf;
+		}
 		xz_err = xz_dec_run(stream->state, &stream->buf);
 
 		if (stream->buf.in_pos == stream->buf.in_size && k < b)

@@ -173,11 +182,13 @@ static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm,
 	if (xz_err != XZ_STREAM_END || k < b)
 		goto out;
 
+	kfree(buf);
 	return total + stream->buf.out_pos;
 
 out:
 	for (; k < b; k++)
 		put_bh(bh[k]);
+	kfree(buf);
 
 	return -EIO;
 }

index 2ec24d128bce..d917c728422b 100644
@@ -66,6 +66,7 @@ static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,
 	struct buffer_head **bh, int b, int offset, int length,
 	struct squashfs_page_actor *output)
 {
+	void *buf = NULL;
 	int zlib_err, zlib_init = 0, k = 0;
 	z_stream *stream = strm;
 

@@ -84,10 +85,19 @@ static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,
 
 		if (stream->avail_out == 0) {
 			stream->next_out = squashfs_next_page(output);
-			if (stream->next_out != NULL)
+			if (!IS_ERR(stream->next_out))
 				stream->avail_out = PAGE_SIZE;
 		}
 
+		if (!stream->next_out) {
+			if (!buf) {
+				buf = kmalloc(PAGE_SIZE, GFP_ATOMIC);
+				if (!buf)
+					goto out;
+			}
+			stream->next_out = buf;
+		}
+
 		if (!zlib_init) {
 			zlib_err = zlib_inflateInit(stream);
 			if (zlib_err != Z_OK) {

@@ -115,11 +125,13 @@ static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,
 	if (k < b)
 		goto out;
 
+	kfree(buf);
 	return stream->total_out;
 
 out:
 	for (; k < b; k++)
 		put_bh(bh[k]);
+	kfree(buf);
 
 	return -EIO;
 }

index 2751476e6b6e..252dfc82ae72 100644
@@ -32,6 +32,8 @@
 #include <linux/string.h>
 #include <linux/buffer_head.h>
 #include <linux/bio.h>
+#include <linux/pagemap.h>
+#include <linux/workqueue.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"

@@ -39,45 +41,357 @@
 #include "decompressor.h"
 #include "page_actor.h"
 
-/*
- * Read the metadata block length, this is stored in the first two
- * bytes of the metadata block.
- */
-static struct buffer_head *get_block_length(struct super_block *sb,
-			u64 *cur_index, int *offset, int *length)
+static struct workqueue_struct *squashfs_read_wq;
+
+struct squashfs_read_request {
+	struct super_block *sb;
+	u64 index;
+	int length;
+	int compressed;
+	int offset;
+	u64 read_end;
+	struct squashfs_page_actor *output;
+	enum {
+		SQUASHFS_COPY,
+		SQUASHFS_DECOMPRESS,
+		SQUASHFS_METADATA,
+	} data_processing;
+	bool synchronous;
+
+	/*
+	 * If the read is synchronous, it is possible to retrieve information
+	 * about the request by setting these pointers.
+	 */
+	int *res;
+	int *bytes_read;
+	int *bytes_uncompressed;
+
+	int nr_buffers;
+	struct buffer_head **bh;
+	struct work_struct offload;
+};
+
+struct squashfs_bio_request {
+	struct buffer_head **bh;
+	int nr_buffers;
+};
+
+static int squashfs_bio_submit(struct squashfs_read_request *req);
+
+int squashfs_init_read_wq(void)
+{
+	squashfs_read_wq = create_workqueue("SquashFS read wq");
+	return !!squashfs_read_wq;
+}
+
+void squashfs_destroy_read_wq(void)
 {
-	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	flush_workqueue(squashfs_read_wq);
+	destroy_workqueue(squashfs_read_wq);
+}
+
+static void free_read_request(struct squashfs_read_request *req, int error)
+{
+	if (!req->synchronous)
+		squashfs_page_actor_free(req->output, error);
+	if (req->res)
+		*(req->res) = error;
+	kfree(req->bh);
+	kfree(req);
+}
+
+static void squashfs_process_blocks(struct squashfs_read_request *req)
+{
+	int error = 0;
+	int bytes, i, length;
+	struct squashfs_sb_info *msblk = req->sb->s_fs_info;
+	struct squashfs_page_actor *actor = req->output;
+	struct buffer_head **bh = req->bh;
+	int nr_buffers = req->nr_buffers;
+
+	for (i = 0; i < nr_buffers; ++i) {
+		if (!bh[i])
+			continue;
+		wait_on_buffer(bh[i]);
+		if (!buffer_uptodate(bh[i]))
+			error = -EIO;
+	}
+	if (error)
+		goto cleanup;
+
+	if (req->data_processing == SQUASHFS_METADATA) {
+		/* Extract the length of the metadata block */
+		if (req->offset != msblk->devblksize - 1) {
+			length = le16_to_cpup((__le16 *)
+					(bh[0]->b_data + req->offset));
+		} else {
+			length = (unsigned char)bh[0]->b_data[req->offset];
+			length |= (unsigned char)bh[1]->b_data[0] << 8;
+		}
+		req->compressed = SQUASHFS_COMPRESSED(length);
+		req->data_processing = req->compressed ? SQUASHFS_DECOMPRESS
+						       : SQUASHFS_COPY;
+		length = SQUASHFS_COMPRESSED_SIZE(length);
+		if (req->index + length + 2 > req->read_end) {
+			for (i = 0; i < nr_buffers; ++i)
+				put_bh(bh[i]);
+			kfree(bh);
+			req->length = length;
+			req->index += 2;
+			squashfs_bio_submit(req);
+			return;
+		}
+		req->length = length;
+		req->offset = (req->offset + 2) % PAGE_SIZE;
+		if (req->offset < 2) {
+			put_bh(bh[0]);
+			++bh;
+			--nr_buffers;
+		}
+	}
+	if (req->bytes_read)
+		*(req->bytes_read) = req->length;
+
+	if (req->data_processing == SQUASHFS_COPY) {
+		squashfs_bh_to_actor(bh, nr_buffers, req->output, req->offset,
+			req->length, msblk->devblksize);
+	} else if (req->data_processing == SQUASHFS_DECOMPRESS) {
+		req->length = squashfs_decompress(msblk, bh, nr_buffers,
+			req->offset, req->length, actor);
+		if (req->length < 0) {
+			error = -EIO;
+			goto cleanup;
+		}
+	}
+
+	/* Last page may have trailing bytes not filled */
+	bytes = req->length % PAGE_SIZE;
+	if (bytes && actor->page[actor->pages - 1])
+		zero_user_segment(actor->page[actor->pages - 1], bytes,
+				  PAGE_SIZE);
+
+cleanup:
+	if (req->bytes_uncompressed)
+		*(req->bytes_uncompressed) = req->length;
+	if (error) {
+		for (i = 0; i < nr_buffers; ++i)
+			if (bh[i])
+				put_bh(bh[i]);
+	}
+	free_read_request(req, error);
+}
+
+static void read_wq_handler(struct work_struct *work)
+{
+	squashfs_process_blocks(container_of(work,
+		    struct squashfs_read_request, offload));
+}
+
+static void squashfs_bio_end_io(struct bio *bio)
+{
+	int i;
+	int error = bio->bi_status;
+	struct squashfs_bio_request *bio_req = bio->bi_private;
+
+	bio_put(bio);
+
+	for (i = 0; i < bio_req->nr_buffers; ++i) {
+		if (!bio_req->bh[i])
+			continue;
+		if (!error)
+			set_buffer_uptodate(bio_req->bh[i]);
+		else
+			clear_buffer_uptodate(bio_req->bh[i]);
+		unlock_buffer(bio_req->bh[i]);
+	}
+	kfree(bio_req);
+}
+
+static int actor_getblks(struct squashfs_read_request *req, u64 block)
+{
+	int i;
+
+	req->bh = kmalloc_array(req->nr_buffers, sizeof(*(req->bh)), GFP_NOIO);
+	if (!req->bh)
+		return -ENOMEM;
+
+	for (i = 0; i < req->nr_buffers; ++i) {
+		req->bh[i] = sb_getblk(req->sb, block + i);
+		if (!req->bh[i]) {
+			while (--i) {
+				if (req->bh[i])
+					put_bh(req->bh[i]);
+			}
+			return -1;
+		}
+	}
+	return 0;
+}
+
+static int squashfs_bio_submit(struct squashfs_read_request *req)
+{
+	struct bio *bio = NULL;
 	struct buffer_head *bh;
+	struct squashfs_bio_request *bio_req = NULL;
+	int b = 0, prev_block = 0;
+	struct squashfs_sb_info *msblk = req->sb->s_fs_info;
+
+	u64 read_start = round_down(req->index, msblk->devblksize);
+	u64 read_end = round_up(req->index + req->length, msblk->devblksize);
+	sector_t block = read_start >> msblk->devblksize_log2;
+	sector_t block_end = read_end >> msblk->devblksize_log2;
+	int offset = read_start - round_down(req->index, PAGE_SIZE);
+	int nr_buffers = block_end - block;
+	int blksz = msblk->devblksize;
+	int bio_max_pages = nr_buffers > BIO_MAX_PAGES ? BIO_MAX_PAGES
+						       : nr_buffers;
+
+	/* Setup the request */
+	req->read_end = read_end;
+	req->offset = req->index - read_start;
+	req->nr_buffers = nr_buffers;
+	if (actor_getblks(req, block) < 0)
+		goto getblk_failed;
 
-	bh = sb_bread(sb, *cur_index);
-	if (bh == NULL)
-		return NULL;
-
-	if (msblk->devblksize - *offset == 1) {
-		*length = (unsigned char) bh->b_data[*offset];
-		put_bh(bh);
-		bh = sb_bread(sb, ++(*cur_index));
-		if (bh == NULL)
-			return NULL;
-		*length |= (unsigned char) bh->b_data[0] << 8;
-		*offset = 1;
-	} else {
-		*length = (unsigned char) bh->b_data[*offset] |
-			(unsigned char) bh->b_data[*offset + 1] << 8;
-		*offset += 2;
-
-		if (*offset == msblk->devblksize) {
-			put_bh(bh);
-			bh = sb_bread(sb, ++(*cur_index));
-			if (bh == NULL)
-				return NULL;
-			*offset = 0;
+	/* Create and submit the BIOs */
+	for (b = 0; b < nr_buffers; ++b, offset += blksz) {
+		bh = req->bh[b];
+		if (!bh || !trylock_buffer(bh))
+			continue;
+		if (buffer_uptodate(bh)) {
+			unlock_buffer(bh);
+			continue;
 		}
+		offset %= PAGE_SIZE;
+
+		/* Append the buffer to the current BIO if it is contiguous */
+		if (bio && bio_req && prev_block + 1 == b) {
+			if (bio_add_page(bio, bh->b_page, blksz, offset)) {
+				bio_req->nr_buffers += 1;
+				prev_block = b;
+				continue;
+			}
+		}
+
+		/* Otherwise, submit the current BIO and create a new one */
+		if (bio)
+			submit_bio(bio);
+		bio_req = kcalloc(1, sizeof(struct squashfs_bio_request),
+				  GFP_NOIO);
+		if (!bio_req)
+			goto req_alloc_failed;
+		bio_req->bh = &req->bh[b];
+		bio = bio_alloc(GFP_NOIO, bio_max_pages);
+		if (!bio)
+			goto bio_alloc_failed;
+		bio_set_dev(bio, req->sb->s_bdev);
+		bio->bi_iter.bi_sector = (block + b)
+				       << (msblk->devblksize_log2 - 9);
+		bio_set_op_attrs(bio, REQ_OP_READ, 0);
+		bio->bi_private = bio_req;
+		bio->bi_end_io = squashfs_bio_end_io;
+
+		bio_add_page(bio, bh->b_page, blksz, offset);
+		bio_req->nr_buffers += 1;
+		prev_block = b;
 	}
+	if (bio)
+		submit_bio(bio);
 
-	return bh;
+	if (req->synchronous)
+		squashfs_process_blocks(req);
+	else {
+		INIT_WORK(&req->offload, read_wq_handler);
+		schedule_work(&req->offload);
+	}
+	return 0;
+
+bio_alloc_failed:
+	kfree(bio_req);
+req_alloc_failed:
+	unlock_buffer(bh);
+	while (--nr_buffers >= b)
+		if (req->bh[nr_buffers])
+			put_bh(req->bh[nr_buffers]);
+	while (--b >= 0)
+		if (req->bh[b])
+			wait_on_buffer(req->bh[b]);
+getblk_failed:
+	free_read_request(req, -ENOMEM);
+	return -ENOMEM;
+}
+
+static int read_metadata_block(struct squashfs_read_request *req,
+			       u64 *next_index)
+{
+	int ret, error, bytes_read = 0, bytes_uncompressed = 0;
+	struct squashfs_sb_info *msblk = req->sb->s_fs_info;
+
+	if (req->index + 2 > msblk->bytes_used) {
+		free_read_request(req, -EINVAL);
+		return -EINVAL;
+	}
+	req->length = 2;
+
+	/* Do not read beyond the end of the device */
+	if (req->index + req->length > msblk->bytes_used)
+		req->length = msblk->bytes_used - req->index;
+	req->data_processing = SQUASHFS_METADATA;
+
+	/*
+	 * Reading metadata is always synchronous because we don't know the
+	 * length in advance and the function is expected to update
+	 * 'next_index' and return the length.
+	 */
+	req->synchronous = true;
+	req->res = &error;
+	req->bytes_read = &bytes_read;
+	req->bytes_uncompressed = &bytes_uncompressed;
+
+	TRACE("Metadata block @ 0x%llx, %scompressed size %d, src size %d\n",
+	      req->index, req->compressed ? "" : "un", bytes_read,
+	      req->output->length);
+
+	ret = squashfs_bio_submit(req);
+	if (ret)
+		return ret;
+	if (error)
+		return error;
+	if (next_index)
+		*next_index += 2 + bytes_read;
+	return bytes_uncompressed;
 }
 
+static int read_data_block(struct squashfs_read_request *req, int length,
+			   u64 *next_index, bool synchronous)
+{
+	int ret, error = 0, bytes_uncompressed = 0, bytes_read = 0;
+
+	req->compressed = SQUASHFS_COMPRESSED_BLOCK(length);
+	req->length = length = SQUASHFS_COMPRESSED_SIZE_BLOCK(length);
+	req->data_processing = req->compressed ? SQUASHFS_DECOMPRESS
+					       : SQUASHFS_COPY;
+
+	req->synchronous = synchronous;
+	if (synchronous) {
+		req->res = &error;
+		req->bytes_read = &bytes_read;
+		req->bytes_uncompressed = &bytes_uncompressed;
+	}
+
+	TRACE("Data block @ 0x%llx, %scompressed size %d, src size %d\n",
+	      req->index, req->compressed ? "" : "un", req->length,
+	      req->output->length);
+
+	ret = squashfs_bio_submit(req);
+	if (ret)
+		return ret;
+	if (synchronous)
+		ret = error ? error : bytes_uncompressed;
+	if (next_index)
+		*next_index += length;
+	return ret;
+}
 
 /*
  * Read and decompress a metadata block or datablock.  Length is non-zero

@@ -88,128 +402,50 @@ static struct buffer_head *get_block_length(struct super_block *sb,
  * generated a larger block - this does occasionally happen with compression
  * algorithms).
  */
-int squashfs_read_data(struct super_block *sb, u64 index, int length,
-		u64 *next_index, struct squashfs_page_actor *output)
+static int __squashfs_read_data(struct super_block *sb, u64 index, int length,
+	u64 *next_index, struct squashfs_page_actor *output, bool sync)
 {
-	struct squashfs_sb_info *msblk = sb->s_fs_info;
-	struct buffer_head **bh;
-	int offset = index & ((1 << msblk->devblksize_log2) - 1);
-	u64 cur_index = index >> msblk->devblksize_log2;
-	int bytes, compressed, b = 0, k = 0, avail, i;
+	struct squashfs_read_request *req;
 
-	bh = kcalloc(((output->length + msblk->devblksize - 1)
-		>> msblk->devblksize_log2) + 1, sizeof(*bh), GFP_KERNEL);
-	if (bh == NULL)
+	req = kcalloc(1, sizeof(struct squashfs_read_request), GFP_KERNEL);
+	if (!req) {
+		if (!sync)
+			squashfs_page_actor_free(output, -ENOMEM);
 		return -ENOMEM;
+	}
 
-	if (length) {
-		/*
-		 * Datablock.
-		 */
-		bytes = -offset;
-		compressed = SQUASHFS_COMPRESSED_BLOCK(length);
-		length = SQUASHFS_COMPRESSED_SIZE_BLOCK(length);
-		if (next_index)
-			*next_index = index + length;
-
-		TRACE("Block @ 0x%llx, %scompressed size %d, src size %d\n",
-			index, compressed ? "" : "un", length, output->length);
-
-		if (length < 0 || length > output->length ||
-				(index + length) > msblk->bytes_used)
-			goto read_failure;
-
-		for (b = 0; bytes < length; b++, cur_index++) {
-			bh[b] = sb_getblk(sb, cur_index);
-			if (bh[b] == NULL)
-				goto block_release;
-			bytes += msblk->devblksize;
-		}
-		ll_rw_block(REQ_OP_READ, 0, b, bh);
-	} else {
-		/*
-		 * Metadata block.
-		 */
-		if ((index + 2) > msblk->bytes_used)
-			goto read_failure;
-
-		bh[0] = get_block_length(sb, &cur_index, &offset, &length);
-		if (bh[0] == NULL)
-			goto read_failure;
-		b = 1;
-
-		bytes = msblk->devblksize - offset;
-		compressed = SQUASHFS_COMPRESSED(length);
-		length = SQUASHFS_COMPRESSED_SIZE(length);
-		if (next_index)
-			*next_index = index + length + 2;
+	req->sb = sb;
+	req->index = index;
+	req->output = output;
 
-		TRACE("Block @ 0x%llx, %scompressed size %d\n", index,
-				compressed ? "" : "un", length);
+	if (next_index)
+		*next_index = index;
 
-		if (length < 0 || length > output->length ||
-					(index + length) > msblk->bytes_used)
-			goto block_release;
+	if (length)
+		length = read_data_block(req, length, next_index, sync);
+	else
+		length = read_metadata_block(req, next_index);
 
-		for (; bytes < length; b++) {
-			bh[b] = sb_getblk(sb, ++cur_index);
-			if (bh[b] == NULL)
-				goto block_release;
-			bytes += msblk->devblksize;
-		}
-		ll_rw_block(REQ_OP_READ, 0, b - 1, bh + 1);
+	if (length < 0) {
+		ERROR("squashfs_read_data failed to read block 0x%llx\n",
+		      (unsigned long long)index);
+		return -EIO;
 	}
 
-	for (i = 0; i < b; i++) {
-		wait_on_buffer(bh[i]);
-		if (!buffer_uptodate(bh[i]))
-			goto block_release;
-	}
-
-	if (compressed) {
-		length = squashfs_decompress(msblk, bh, b, offset, length,
-			output);
-		if (length < 0)
-			goto read_failure;
-	} else {
-		/*
-		 * Block is uncompressed.
-		 */
-		int in, pg_offset = 0;
-		void *data = squashfs_first_page(output);
-
-		for (bytes = length; k < b; k++) {
-			in = min(bytes, msblk->devblksize - offset);
-			bytes -= in;
-			while (in) {
-				if (pg_offset == PAGE_SIZE) {
-					data = squashfs_next_page(output);
-					pg_offset = 0;
-				}
-				avail = min_t(int, in, PAGE_SIZE -
-						pg_offset);
-				memcpy(data + pg_offset, bh[k]->b_data + offset,
-						avail);
-				in -= avail;
-				pg_offset += avail;
-				offset += avail;
-			}
-			offset = 0;
-			put_bh(bh[k]);
-		}
-		squashfs_finish_page(output);
-	}
-
-	kfree(bh);
 	return length;
+}
+
+int squashfs_read_data(struct super_block *sb, u64 index, int length,
+	u64 *next_index, struct squashfs_page_actor *output)
+{
+	return __squashfs_read_data(sb, index, length, next_index, output,
+				    true);
+}
 
-block_release:
-	for (; k < b; k++)
-		put_bh(bh[k]);
+int squashfs_read_data_async(struct super_block *sb, u64 index, int length,
+	u64 *next_index, struct squashfs_page_actor *output)
+{
 
-read_failure:
-	ERROR("squashfs_read_data failed to read block 0x%llx\n",
-					(unsigned long long) index);
-	kfree(bh);
-	return -EIO;
+	return __squashfs_read_data(sb, index, length, next_index, output,
+				    false);
 }

223 lines not on this page · raw message

index 887d6d270080..66d7194563b6 100644
@@ -28,8 +28,12 @@
 #define WARNING(s, args...)	pr_warn("SQUASHFS: "s, ## args)
 
 /* block.c */
+extern int squashfs_init_read_wq(void);
+extern void squashfs_destroy_read_wq(void);
 extern int squashfs_read_data(struct super_block *, u64, int, u64 *,
 				struct squashfs_page_actor *);
+extern int squashfs_read_data_async(struct super_block *, u64, int, u64 *,
+				struct squashfs_page_actor *);
 
 /* cache.c */
 extern struct squashfs_cache *squashfs_cache_init(char *, int, int);

index cf01e15a7b16..e2a0a7342bf8 100644
@@ -444,9 +444,15 @@ static int __init init_squashfs_fs(void)
 	if (err)
 		return err;
 
+	if (!squashfs_init_read_wq()) {
+		destroy_inodecache();
+		return -ENOMEM;
+	}
+
 	err = register_filesystem(&squashfs_fs_type);
 	if (err) {
 		destroy_inodecache();
+		squashfs_destroy_read_wq();
 		return err;
 	}
 

@@ -460,6 +466,7 @@ static void __exit exit_squashfs_fs(void)
 {
 	unregister_filesystem(&squashfs_fs_type);
 	destroy_inodecache();
+	squashfs_destroy_read_wq();
 }
 
 

index 13d80947bf9e..bb2e77ee4209 100644
@@ -47,6 +47,7 @@
 #include <linux/string.h>
 #include <linux/pagemap.h>
 #include <linux/mutex.h>
+#include <linux/mm_inline.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"

@@ -438,6 +439,21 @@ static int squashfs_readpage_fragment(struct page *page)
 	return res;
 }
 
+static int squashfs_readpages_fragment(struct page *page,
+	struct list_head *readahead_pages, struct address_space *mapping)
+{
+	if (!page) {
+		page = lru_to_page(readahead_pages);
+		list_del(&page->lru);
+		if (add_to_page_cache_lru(page, mapping, page->index,
+			mapping_gfp_constraint(mapping, GFP_KERNEL))) {
+			put_page(page);
+			return 0;
+		}
+	}
+	return squashfs_readpage_fragment(page);
+}
+
 static int squashfs_readpage_sparse(struct page *page, int index, int file_end)
 {
 	struct inode *inode = page->mapping->host;

@@ -450,54 +466,105 @@ static int squashfs_readpage_sparse(struct page *page, int index, int file_end)
 	return 0;
 }
 
-static int squashfs_readpage(struct file *file, struct page *page)
+static int squashfs_readpages_sparse(struct page *page,
+	struct list_head *readahead_pages, int index, int file_end,
+	struct address_space *mapping)
 {
-	struct inode *inode = page->mapping->host;
+	if (!page) {
+		page = lru_to_page(readahead_pages);
+		list_del(&page->lru);
+		if (add_to_page_cache_lru(page, mapping, page->index,
+			mapping_gfp_constraint(mapping, GFP_KERNEL))) {
+			put_page(page);
+			return 0;
+		}
+	}
+	return squashfs_readpage_sparse(page, index, file_end);
+}
+
+static int __squashfs_readpages(struct file *file, struct page *page,
+	struct list_head *readahead_pages, unsigned int nr_pages,
+	struct address_space *mapping)
+{
+	struct inode *inode = mapping->host;
 	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
-	int index = page->index >> (msblk->block_log - PAGE_SHIFT);
 	int file_end = i_size_read(inode) >> msblk->block_log;
 	int res;
-	void *pageaddr;
 
-	TRACE("Entered squashfs_readpage, page index %lx, start block %llx\n",
-				page->index, squashfs_i(inode)->start);
+	do {
+		struct page *cur_page = page ? page
+					     : lru_to_page(readahead_pages);
+		int page_index = cur_page->index;
+		int index = page_index >> (msblk->block_log - PAGE_SHIFT);
+
+		if (page_index >= ((i_size_read(inode) + PAGE_SIZE - 1) >>
+						PAGE_SHIFT))
+			return 1;
+
+		if (index < file_end || squashfs_i(inode)->fragment_block ==
+						SQUASHFS_INVALID_BLK) {
+			u64 block = 0;
+			int bsize = read_blocklist(inode, index, &block);
+
+			if (bsize < 0)
+				return -1;
+
+			if (bsize == 0) {
+				res = squashfs_readpages_sparse(page,
+					readahead_pages, index, file_end,
+					mapping);
+			} else {
+				res = squashfs_readpages_block(page,
+					readahead_pages, &nr_pages, mapping,
+					page_index, block, bsize);
+			}
+		} else {
+			res = squashfs_readpages_fragment(page,
+				readahead_pages, mapping);
+		}
+		if (res)
+			return 0;
+		page = NULL;
+	} while (readahead_pages && !list_empty(readahead_pages));
+
+	return 0;
+}
+
+static int squashfs_readpage(struct file *file, struct page *page)
+{
+	int ret;
 
-	if (page->index >= ((i_size_read(inode) + PAGE_SIZE - 1) >>
-					PAGE_SHIFT))
-		goto out;
+	TRACE("Entered squashfs_readpage, page index %lx, start block %llx\n",
+	      page->index, squashfs_i(page->mapping->host)->start);
 
-	if (index < file_end || squashfs_i(inode)->fragment_block ==
-					SQUASHFS_INVALID_BLK) {
-		u64 block = 0;
-		int bsize = read_blocklist(inode, index, &block);
-		if (bsize < 0)
-			goto error_out;
+	get_page(page);
 
-		if (bsize == 0)
-			res = squashfs_readpage_sparse(page, index, file_end);
+	ret = __squashfs_readpages(file, page, NULL, 1, page->mapping);
+	if (ret) {
+		flush_dcache_page(page);
+		if (ret < 0)
+			SetPageError(page);
 		else
-			res = squashfs_readpage_block(page, block, bsize);
-	} else
-		res = squashfs_readpage_fragment(page);
-
-	if (!res)
-		return 0;
-
-error_out:
-	SetPageError(page);
-out:
-	pageaddr = kmap_atomic(page);
-	memset(pageaddr, 0, PAGE_SIZE);
-	kunmap_atomic(pageaddr);
-	flush_dcache_page(page);
-	if (!PageError(page))
-		SetPageUptodate(page);
-	unlock_page(page);
+			SetPageUptodate(page);
+		zero_user_segment(page, 0, PAGE_SIZE);
+		unlock_page(page);
+		put_page(page);
+	}
 
 	return 0;
 }
 
+static int squashfs_readpages(struct file *file, struct address_space *mapping,
+			      struct list_head *pages, unsigned int nr_pages)
+{
+	TRACE("Entered squashfs_readpages, %u pages, first page index %lx\n",
+		nr_pages, lru_to_page(pages)->index);
+	__squashfs_readpages(file, NULL, pages, nr_pages, mapping);
+	return 0;
+}
+
 
 const struct address_space_operations squashfs_aops = {
-	.readpage = squashfs_readpage
+	.readpage = squashfs_readpage,
+	.readpages = squashfs_readpages,
 };

110 lines not on this page · raw message

index 66d7194563b6..f4faab52a879 100644
@@ -74,8 +74,9 @@ extern __le64 *squashfs_read_fragment_index_table(struct super_block *,
 void squashfs_copy_cache(struct page *, struct squashfs_cache_entry *, int,
 				int);
 
-/* file_xxx.c */
-extern int squashfs_readpage_block(struct page *, u64, int);
+/* file_direct.c */
+extern int squashfs_readpages_block(struct page *, struct list_head *,
+	unsigned int *, struct address_space *, int, u64, int);
 
 /* id.c */
 extern int squashfs_get_id(struct super_block *, unsigned int, unsigned int *);

index 252dfc82ae72..37658b6e83ee 100644
@@ -207,6 +207,22 @@ static void squashfs_bio_end_io(struct bio *bio)
 	kfree(bio_req);
 }
 
+static int bh_is_optional(struct squashfs_read_request *req, int idx)
+{
+	int start_idx, end_idx;
+	struct squashfs_sb_info *msblk = req->sb->s_fs_info;
+
+	start_idx = (idx * msblk->devblksize - req->offset) >> PAGE_SHIFT;
+	end_idx = ((idx + 1) * msblk->devblksize - req->offset + 1) >> PAGE_SHIFT;
+	if (start_idx >= req->output->pages)
+		return 1;
+	if (start_idx < 0)
+		start_idx = end_idx;
+	if (end_idx >= req->output->pages)
+		end_idx = start_idx;
+	return !req->output->page[start_idx] && !req->output->page[end_idx];
+}
+
 static int actor_getblks(struct squashfs_read_request *req, u64 block)
 {
 	int i;

@@ -216,6 +232,15 @@ static int actor_getblks(struct squashfs_read_request *req, u64 block)
 		return -ENOMEM;
 
 	for (i = 0; i < req->nr_buffers; ++i) {
+		/*
+		 * When dealing with an uncompressed block, the actor may
+		 * contains NULL pages. There's no need to read the buffers
+		 * associated with these pages.
+		 */
+		if (!req->compressed && bh_is_optional(req, i)) {
+			req->bh[i] = NULL;
+			continue;
+		}
 		req->bh[i] = sb_getblk(req->sb, block + i);
 		if (!req->bh[i]) {
 			while (--i) {

index a978811de327..dc87f77ce11e 100644
@@ -111,15 +111,38 @@ int squashfs_readpages_block(struct page *target_page,
 	struct squashfs_page_actor *actor;
 	struct inode *inode = mapping->host;
 	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
-	int file_end = (i_size_read(inode) - 1) >> PAGE_SHIFT;
+	int start_index, end_index, file_end, actor_pages, res;
 	int mask = (1 << (msblk->block_log - PAGE_SHIFT)) - 1;
-	int start_index = page_index & ~mask;
-	int end_index = start_index | mask;
-	int actor_pages, res;
 
-	if (end_index > file_end)
-		end_index = file_end;
-	actor_pages = end_index - start_index + 1;
+	/*
+	 * If readpage() is called on an uncompressed datablock, we can just
+	 * read the pages instead of fetching the whole block.
+	 * This greatly improves the performance when a process keep doing
+	 * random reads because we only fetch the necessary data.
+	 * The readahead algorithm will take care of doing speculative reads
+	 * if necessary.
+	 * We can't read more than 1 block even if readahead provides use more
+	 * pages because we don't know yet if the next block is compressed or
+	 * not.
+	 */
+	if (bsize && !SQUASHFS_COMPRESSED_BLOCK(bsize)) {
+		u64 block_end = block + msblk->block_size;
+
+		block += (page_index & mask) * PAGE_SIZE;
+		actor_pages = (block_end - block) / PAGE_SIZE;
+		if (*nr_pages < actor_pages)
+			actor_pages = *nr_pages;
+		start_index = page_index;
+		bsize = min_t(int, bsize, (PAGE_SIZE * actor_pages)
+					  | SQUASHFS_COMPRESSED_BIT_BLOCK);
+	} else {
+		file_end = (i_size_read(inode) - 1) >> PAGE_SHIFT;
+		start_index = page_index & ~mask;
+		end_index = start_index | mask;
+		if (end_index > file_end)
+			end_index = file_end;
+		actor_pages = end_index - start_index + 1;
+	}
 
 	actor = actor_from_page_cache(actor_pages, target_page,
 				      readahead_pages, nr_pages, start_index,