* [PATCH 1/3] Squashfs: Generalise paging handling in the decompressors
2013-10-11 6:19 [PATCH 0/3] Squashfs: Directly decompress into the page cache for file data Phillip Lougher
@ 2013-10-11 6:19 ` Phillip Lougher
2013-10-11 6:19 ` [PATCH 2/3] Squashfs: restructure squashfs_readpage() Phillip Lougher
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Phillip Lougher @ 2013-10-11 6:19 UTC (permalink / raw)
To: linux-kernel; +Cc: minchan, Phillip Lougher
Generalise the decompressors by adding a page handler
abstraction. This adds helpers to allow the decompressors
to access and process the output buffers in an implementation
independant manner.
This allows different types of output buffer to be passed
to the decompressors, with the implementation specific
aspects handled at decompression time, but without the
knowledge being held in the decompressor wrapper code.
This will allow the decompressors to handle Squashfs
cache buffers, and page cache pages.
This patch adds the abstraction and an implementation for
the caches.
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
---
fs/squashfs/block.c | 27 +++++++++++---------
fs/squashfs/cache.c | 28 ++++++++++++++++----
fs/squashfs/decompressor.c | 14 +++++++---
fs/squashfs/decompressor.h | 5 ++--
fs/squashfs/decompressor_single.c | 9 +++----
fs/squashfs/lzo_wrapper.c | 27 +++++++++++++-------
fs/squashfs/page_actor.h | 54 +++++++++++++++++++++++++++++++++++++++
fs/squashfs/squashfs.h | 8 +++---
fs/squashfs/squashfs_fs_sb.h | 1 +
fs/squashfs/xz_wrapper.c | 22 +++++++++-------
fs/squashfs/zlib_wrapper.c | 24 ++++++++++-------
11 files changed, 161 insertions(+), 58 deletions(-)
create mode 100644 fs/squashfs/page_actor.h
diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index 10993e9..f59f752 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -36,6 +36,7 @@
#include "squashfs_fs_sb.h"
#include "squashfs.h"
#include "decompressor.h"
+#include "page_actor.h"
/*
* Read the metadata block length, this is stored in the first two
@@ -86,16 +87,16 @@ 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, void **buffer, u64 index,
- int length, u64 *next_index, int srclength, int pages)
+int squashfs_read_data(struct super_block *sb, u64 index, int length,
+ u64 *next_index, struct squashfs_page_actor *output)
{
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, page = 0, avail, i;
+ int bytes, compressed, b = 0, k = 0, avail, i;
- bh = kcalloc(((srclength + msblk->devblksize - 1)
+ bh = kcalloc(((output->length + msblk->devblksize - 1)
>> msblk->devblksize_log2) + 1, sizeof(*bh), GFP_KERNEL);
if (bh == NULL)
return -ENOMEM;
@@ -111,9 +112,9 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
*next_index = index + length;
TRACE("Block @ 0x%llx, %scompressed size %d, src size %d\n",
- index, compressed ? "" : "un", length, srclength);
+ index, compressed ? "" : "un", length, output->length);
- if (length < 0 || length > srclength ||
+ if (length < 0 || length > output->length ||
(index + length) > msblk->bytes_used)
goto read_failure;
@@ -145,7 +146,7 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
TRACE("Block @ 0x%llx, %scompressed size %d\n", index,
compressed ? "" : "un", length);
- if (length < 0 || length > srclength ||
+ if (length < 0 || length > output->length ||
(index + length) > msblk->bytes_used)
goto block_release;
@@ -165,8 +166,8 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
}
if (compressed) {
- length = squashfs_decompress(msblk, buffer, bh, b, offset,
- length, srclength, pages);
+ length = squashfs_decompress(msblk, bh, b, offset, length,
+ output);
if (length < 0)
goto read_failure;
} else {
@@ -174,19 +175,20 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
* 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_CACHE_SIZE) {
- page++;
+ data = squashfs_next_page(output);
pg_offset = 0;
}
avail = min_t(int, in, PAGE_CACHE_SIZE -
pg_offset);
- memcpy(buffer[page] + pg_offset,
- bh[k]->b_data + offset, avail);
+ memcpy(data + pg_offset, bh[k]->b_data + offset,
+ avail);
in -= avail;
pg_offset += avail;
offset += avail;
@@ -194,6 +196,7 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
offset = 0;
put_bh(bh[k]);
}
+ squashfs_finish_page(output);
}
kfree(bh);
diff --git a/fs/squashfs/cache.c b/fs/squashfs/cache.c
index af0b738..1cb70a0 100644
--- a/fs/squashfs/cache.c
+++ b/fs/squashfs/cache.c
@@ -56,6 +56,7 @@
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs.h"
+#include "page_actor.h"
/*
* Look-up block in cache, and increment usage count. If not in cache, read
@@ -119,9 +120,8 @@ struct squashfs_cache_entry *squashfs_cache_get(struct super_block *sb,
entry->error = 0;
spin_unlock(&cache->lock);
- entry->length = squashfs_read_data(sb, entry->data,
- block, length, &entry->next_index,
- cache->block_size, cache->pages);
+ entry->length = squashfs_read_data(sb, block, length,
+ &entry->next_index, entry->actor);
spin_lock(&cache->lock);
@@ -220,6 +220,7 @@ void squashfs_cache_delete(struct squashfs_cache *cache)
kfree(cache->entry[i].data[j]);
kfree(cache->entry[i].data);
}
+ kfree(cache->entry[i].actor);
}
kfree(cache->entry);
@@ -280,6 +281,13 @@ struct squashfs_cache *squashfs_cache_init(char *name, int entries,
goto cleanup;
}
}
+
+ entry->actor = squashfs_page_actor_init(entry->data,
+ cache->pages, 0);
+ if (entry->actor == NULL) {
+ ERROR("Failed to allocate %s cache entry\n", name);
+ goto cleanup;
+ }
}
return cache;
@@ -410,6 +418,7 @@ void *squashfs_read_table(struct super_block *sb, u64 block, int length)
int pages = (length + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
int i, res;
void *table, *buffer, **data;
+ struct squashfs_page_actor *actor;
table = buffer = kmalloc(length, GFP_KERNEL);
if (table == NULL)
@@ -421,19 +430,28 @@ void *squashfs_read_table(struct super_block *sb, u64 block, int length)
goto failed;
}
+ actor = squashfs_page_actor_init(data, pages, length);
+ if (actor == NULL) {
+ res = -ENOMEM;
+ goto failed2;
+ }
+
for (i = 0; i < pages; i++, buffer += PAGE_CACHE_SIZE)
data[i] = buffer;
- res = squashfs_read_data(sb, data, block, length |
- SQUASHFS_COMPRESSED_BIT_BLOCK, NULL, length, pages);
+ res = squashfs_read_data(sb, block, length |
+ SQUASHFS_COMPRESSED_BIT_BLOCK, NULL, actor);
kfree(data);
+ kfree(actor);
if (res < 0)
goto failed;
return table;
+failed2:
+ kfree(data);
failed:
kfree(table);
return ERR_PTR(res);
diff --git a/fs/squashfs/decompressor.c b/fs/squashfs/decompressor.c
index 6708c74..504115f 100644
--- a/fs/squashfs/decompressor.c
+++ b/fs/squashfs/decompressor.c
@@ -30,6 +30,7 @@
#include "squashfs_fs_sb.h"
#include "decompressor.h"
#include "squashfs.h"
+#include "page_actor.h"
/*
* This file (and decompressor.h) implements a decompressor framework for
@@ -87,6 +88,7 @@ static void *get_comp_opts(struct super_block *sb, unsigned short flags)
{
struct squashfs_sb_info *msblk = sb->s_fs_info;
void *buffer = NULL, *comp_opts;
+ struct squashfs_page_actor *actor = NULL;
int length = 0;
/*
@@ -99,9 +101,14 @@ static void *get_comp_opts(struct super_block *sb, unsigned short flags)
goto out;
}
- length = squashfs_read_data(sb, &buffer,
- sizeof(struct squashfs_super_block), 0, NULL,
- PAGE_CACHE_SIZE, 1);
+ actor = squashfs_page_actor_init(&buffer, 1, 0);
+ if (actor == NULL) {
+ comp_opts = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+
+ length = squashfs_read_data(sb,
+ sizeof(struct squashfs_super_block), 0, NULL, actor);
if (length < 0) {
comp_opts = ERR_PTR(length);
@@ -112,6 +119,7 @@ static void *get_comp_opts(struct super_block *sb, unsigned short flags)
comp_opts = squashfs_comp_opts(msblk, buffer, length);
out:
+ kfree(actor);
kfree(buffer);
return comp_opts;
}
diff --git a/fs/squashfs/decompressor.h b/fs/squashfs/decompressor.h
index 6cdb20a..af09853 100644
--- a/fs/squashfs/decompressor.h
+++ b/fs/squashfs/decompressor.h
@@ -27,8 +27,9 @@ struct squashfs_decompressor {
void *(*init)(struct squashfs_sb_info *, void *);
void *(*comp_opts)(struct squashfs_sb_info *, void *, int);
void (*free)(void *);
- int (*decompress)(struct squashfs_sb_info *, void *, void **,
- struct buffer_head **, int, int, int, int, int);
+ int (*decompress)(struct squashfs_sb_info *, void *,
+ struct buffer_head **, int, int, int,
+ struct squashfs_page_actor *);
int id;
char *name;
int supported;
diff --git a/fs/squashfs/decompressor_single.c b/fs/squashfs/decompressor_single.c
index cb1e316..8b2e56c 100644
--- a/fs/squashfs/decompressor_single.c
+++ b/fs/squashfs/decompressor_single.c
@@ -81,16 +81,15 @@ void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
}
-int squashfs_decompress(struct squashfs_sb_info *msblk,
- void **buffer, struct buffer_head **bh, int b, int offset, int length,
- int srclength, int pages)
+int squashfs_decompress(struct squashfs_sb_info *msblk, struct buffer_head **bh,
+ int b, int offset, int length, struct squashfs_page_actor *output)
{
int res;
struct squashfs_stream *stream = msblk->stream;
mutex_lock(&stream->mutex);
- res = msblk->decompressor->decompress(msblk, stream->stream, buffer,
- bh, b, offset, length, srclength, pages);
+ res = msblk->decompressor->decompress(msblk, stream->stream, bh, b,
+ offset, length, output);
mutex_unlock(&stream->mutex);
if (res < 0)
diff --git a/fs/squashfs/lzo_wrapper.c b/fs/squashfs/lzo_wrapper.c
index 75c3b57..244b9fb 100644
--- a/fs/squashfs/lzo_wrapper.c
+++ b/fs/squashfs/lzo_wrapper.c
@@ -31,6 +31,7 @@
#include "squashfs_fs_sb.h"
#include "squashfs.h"
#include "decompressor.h"
+#include "page_actor.h"
struct squashfs_lzo {
void *input;
@@ -75,13 +76,13 @@ static void lzo_free(void *strm)
static int lzo_uncompress(struct squashfs_sb_info *msblk, void *strm,
- void **buffer, struct buffer_head **bh, int b, int offset, int length,
- int srclength, int pages)
+ struct buffer_head **bh, int b, int offset, int length,
+ struct squashfs_page_actor *output)
{
struct squashfs_lzo *stream = strm;
- void *buff = stream->input;
+ void *buff = stream->input, *data;
int avail, i, bytes = length, res;
- size_t out_len = srclength;
+ size_t out_len = output->length;
for (i = 0; i < b; i++) {
avail = min(bytes, msblk->devblksize - offset);
@@ -98,12 +99,20 @@ static int lzo_uncompress(struct squashfs_sb_info *msblk, void *strm,
goto failed;
res = bytes = (int)out_len;
- for (i = 0, buff = stream->output; bytes && i < pages; i++) {
- avail = min_t(int, bytes, PAGE_CACHE_SIZE);
- memcpy(buffer[i], buff, avail);
- buff += avail;
- bytes -= avail;
+ data = squashfs_first_page(output);
+ buff = stream->output;
+ while (data) {
+ if (bytes <= PAGE_CACHE_SIZE) {
+ memcpy(data, buff, bytes);
+ break;
+ } else {
+ memcpy(data, buff, PAGE_CACHE_SIZE);
+ buff += PAGE_CACHE_SIZE;
+ bytes -= PAGE_CACHE_SIZE;
+ data = squashfs_next_page(output);
+ }
}
+ squashfs_finish_page(output);
return res;
diff --git a/fs/squashfs/page_actor.h b/fs/squashfs/page_actor.h
new file mode 100644
index 0000000..19a66a3
--- /dev/null
+++ b/fs/squashfs/page_actor.h
@@ -0,0 +1,54 @@
+#ifndef PAGE_ACTOR_H
+#define PAGE_ACTOR_H
+/*
+ * 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.
+ */
+
+struct squashfs_page_actor {
+ void **page;
+ int pages;
+ int length;
+ int next_page;
+};
+
+static inline struct squashfs_page_actor *squashfs_page_actor_init(void **page,
+ int pages, int length)
+{
+ struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL);
+
+ if (actor == NULL)
+ return NULL;
+
+ if (length)
+ actor->length = length;
+ else
+ actor->length = pages * PAGE_CACHE_SIZE;
+ actor->page = page;
+ actor->pages = pages;
+ actor->next_page = 0;
+ return actor;
+}
+
+static inline void *squashfs_first_page(struct squashfs_page_actor *actor)
+{
+ actor->next_page = 1;
+ return actor->page[0];
+}
+
+static inline void *squashfs_next_page(struct squashfs_page_actor *actor)
+{
+ if (actor->next_page == actor->pages)
+ return NULL;
+
+ return actor->page[actor->next_page++];
+}
+
+static inline void squashfs_finish_page(struct squashfs_page_actor *actor)
+{
+ /* empty */
+}
+#endif
diff --git a/fs/squashfs/squashfs.h b/fs/squashfs/squashfs.h
index 2e2751d..6a97e63 100644
--- a/fs/squashfs/squashfs.h
+++ b/fs/squashfs/squashfs.h
@@ -28,8 +28,8 @@
#define WARNING(s, args...) pr_warning("SQUASHFS: "s, ## args)
/* block.c */
-extern int squashfs_read_data(struct super_block *, void **, u64, int, u64 *,
- int, int);
+extern int squashfs_read_data(struct super_block *, u64, int, u64 *,
+ struct squashfs_page_actor *);
/* cache.c */
extern struct squashfs_cache *squashfs_cache_init(char *, int, int);
@@ -53,8 +53,8 @@ extern void *squashfs_decompressor_setup(struct super_block *, unsigned short);
/* decompressor_xxx.c */
extern void *squashfs_decompressor_create(struct squashfs_sb_info *, void *);
extern void squashfs_decompressor_destroy(struct squashfs_sb_info *);
-extern int squashfs_decompress(struct squashfs_sb_info *, void **,
- struct buffer_head **, int, int, int, int, int);
+extern int squashfs_decompress(struct squashfs_sb_info *, struct buffer_head **,
+ int, int, int, struct squashfs_page_actor *);
extern int squashfs_max_decompressors(void);
/* export.c */
diff --git a/fs/squashfs/squashfs_fs_sb.h b/fs/squashfs/squashfs_fs_sb.h
index 9cdcf41..1da565c 100644
--- a/fs/squashfs/squashfs_fs_sb.h
+++ b/fs/squashfs/squashfs_fs_sb.h
@@ -50,6 +50,7 @@ struct squashfs_cache_entry {
wait_queue_head_t wait_queue;
struct squashfs_cache *cache;
void **data;
+ struct squashfs_page_actor *actor;
};
struct squashfs_sb_info {
diff --git a/fs/squashfs/xz_wrapper.c b/fs/squashfs/xz_wrapper.c
index 5d1d07c..c609624 100644
--- a/fs/squashfs/xz_wrapper.c
+++ b/fs/squashfs/xz_wrapper.c
@@ -32,6 +32,7 @@
#include "squashfs_fs_sb.h"
#include "squashfs.h"
#include "decompressor.h"
+#include "page_actor.h"
struct squashfs_xz {
struct xz_dec *state;
@@ -129,11 +130,11 @@ static void squashfs_xz_free(void *strm)
static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm,
- void **buffer, struct buffer_head **bh, int b, int offset, int length,
- int srclength, int pages)
+ struct buffer_head **bh, int b, int offset, int length,
+ struct squashfs_page_actor *output)
{
enum xz_ret xz_err;
- int avail, total = 0, k = 0, page = 0;
+ int avail, total = 0, k = 0;
struct squashfs_xz *stream = strm;
xz_dec_reset(stream->state);
@@ -141,7 +142,7 @@ static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm,
stream->buf.in_size = 0;
stream->buf.out_pos = 0;
stream->buf.out_size = PAGE_CACHE_SIZE;
- stream->buf.out = buffer[page++];
+ stream->buf.out = squashfs_first_page(output);
do {
if (stream->buf.in_pos == stream->buf.in_size && k < b) {
@@ -153,11 +154,12 @@ static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm,
offset = 0;
}
- if (stream->buf.out_pos == stream->buf.out_size
- && page < pages) {
- stream->buf.out = buffer[page++];
- stream->buf.out_pos = 0;
- total += PAGE_CACHE_SIZE;
+ if (stream->buf.out_pos == stream->buf.out_size) {
+ stream->buf.out = squashfs_next_page(output);
+ if (stream->buf.out != NULL) {
+ stream->buf.out_pos = 0;
+ total += PAGE_CACHE_SIZE;
+ }
}
xz_err = xz_dec_run(stream->state, &stream->buf);
@@ -166,6 +168,8 @@ static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm,
put_bh(bh[k++]);
} while (xz_err == XZ_OK);
+ squashfs_finish_page(output);
+
if (xz_err != XZ_STREAM_END || k < b)
goto out;
diff --git a/fs/squashfs/zlib_wrapper.c b/fs/squashfs/zlib_wrapper.c
index bb04902..8727cab 100644
--- a/fs/squashfs/zlib_wrapper.c
+++ b/fs/squashfs/zlib_wrapper.c
@@ -32,6 +32,7 @@
#include "squashfs_fs_sb.h"
#include "squashfs.h"
#include "decompressor.h"
+#include "page_actor.h"
static void *zlib_init(struct squashfs_sb_info *dummy, void *buff)
{
@@ -62,14 +63,14 @@ static void zlib_free(void *strm)
static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,
- void **buffer, struct buffer_head **bh, int b, int offset, int length,
- int srclength, int pages)
+ struct buffer_head **bh, int b, int offset, int length,
+ struct squashfs_page_actor *output)
{
- int zlib_err, zlib_init = 0;
- int k = 0, page = 0;
+ int zlib_err, zlib_init = 0, k = 0;
z_stream *stream = strm;
- stream->avail_out = 0;
+ stream->avail_out = PAGE_CACHE_SIZE;
+ stream->next_out = squashfs_first_page(output);
stream->avail_in = 0;
do {
@@ -81,15 +82,18 @@ static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,
offset = 0;
}
- if (stream->avail_out == 0 && page < pages) {
- stream->next_out = buffer[page++];
- stream->avail_out = PAGE_CACHE_SIZE;
+ if (stream->avail_out == 0) {
+ stream->next_out = squashfs_next_page(output);
+ if (stream->next_out != NULL)
+ stream->avail_out = PAGE_CACHE_SIZE;
}
if (!zlib_init) {
zlib_err = zlib_inflateInit(stream);
- if (zlib_err != Z_OK)
+ if (zlib_err != Z_OK) {
+ squashfs_finish_page(output);
goto out;
+ }
zlib_init = 1;
}
@@ -99,6 +103,8 @@ static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,
put_bh(bh[k++]);
} while (zlib_err == Z_OK);
+ squashfs_finish_page(output);
+
if (zlib_err != Z_STREAM_END)
goto out;
--
1.8.3.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 2/3] Squashfs: restructure squashfs_readpage()
2013-10-11 6:19 [PATCH 0/3] Squashfs: Directly decompress into the page cache for file data Phillip Lougher
2013-10-11 6:19 ` [PATCH 1/3] Squashfs: Generalise paging handling in the decompressors Phillip Lougher
@ 2013-10-11 6:19 ` Phillip Lougher
2013-10-11 6:19 ` [PATCH 3/3] Squashfs: Directly decompress into the page cache for file data Phillip Lougher
2013-10-11 8:03 ` [PATCH 0/3] " Minchan Kim
3 siblings, 0 replies; 6+ messages in thread
From: Phillip Lougher @ 2013-10-11 6:19 UTC (permalink / raw)
To: linux-kernel; +Cc: minchan, Phillip Lougher
Restructure squashfs_readpage() splitting it into separate
functions for datablocks, fragments and sparse blocks.
Move the memcpying (from squashfs cache entry) implementation of
squashfs_readpage_block into file_cache.c
This allows different implementations to be supported
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
---
fs/squashfs/Makefile | 1 +
fs/squashfs/file.c | 142 ++++++++++++++++++++++++-----------------------
fs/squashfs/file_cache.c | 38 +++++++++++++
fs/squashfs/squashfs.h | 7 +++
4 files changed, 118 insertions(+), 70 deletions(-)
create mode 100644 fs/squashfs/file_cache.c
diff --git a/fs/squashfs/Makefile b/fs/squashfs/Makefile
index c223c84..14cfc41 100644
--- a/fs/squashfs/Makefile
+++ b/fs/squashfs/Makefile
@@ -5,6 +5,7 @@
obj-$(CONFIG_SQUASHFS) += squashfs.o
squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
squashfs-y += namei.o super.o symlink.o decompressor.o decompressor_single.o
+squashfs-y += file_cache.o
squashfs-$(CONFIG_SQUASHFS_XATTR) += xattr.o xattr_id.o
squashfs-$(CONFIG_SQUASHFS_LZO) += lzo_wrapper.o
squashfs-$(CONFIG_SQUASHFS_XZ) += xz_wrapper.o
diff --git a/fs/squashfs/file.c b/fs/squashfs/file.c
index 8ca62c2..e5c9689 100644
--- a/fs/squashfs/file.c
+++ b/fs/squashfs/file.c
@@ -370,77 +370,15 @@ static int read_blocklist(struct inode *inode, int index, u64 *block)
return le32_to_cpu(size);
}
-
-static int squashfs_readpage(struct file *file, struct page *page)
+/* Copy data into page cache */
+void squashfs_copy_cache(struct page *page, struct squashfs_cache_entry *buffer,
+ int bytes, int offset)
{
struct inode *inode = page->mapping->host;
struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
- int bytes, i, offset = 0, sparse = 0;
- struct squashfs_cache_entry *buffer = NULL;
void *pageaddr;
-
- int mask = (1 << (msblk->block_log - PAGE_CACHE_SHIFT)) - 1;
- int index = page->index >> (msblk->block_log - PAGE_CACHE_SHIFT);
- int start_index = page->index & ~mask;
- int end_index = start_index | mask;
- int file_end = i_size_read(inode) >> msblk->block_log;
-
- TRACE("Entered squashfs_readpage, page index %lx, start block %llx\n",
- page->index, squashfs_i(inode)->start);
-
- if (page->index >= ((i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
- PAGE_CACHE_SHIFT))
- goto out;
-
- if (index < file_end || squashfs_i(inode)->fragment_block ==
- SQUASHFS_INVALID_BLK) {
- /*
- * Reading a datablock from disk. Need to read block list
- * to get location and block size.
- */
- u64 block = 0;
- int bsize = read_blocklist(inode, index, &block);
- if (bsize < 0)
- goto error_out;
-
- if (bsize == 0) { /* hole */
- bytes = index == file_end ?
- (i_size_read(inode) & (msblk->block_size - 1)) :
- msblk->block_size;
- sparse = 1;
- } else {
- /*
- * Read and decompress datablock.
- */
- buffer = squashfs_get_datablock(inode->i_sb,
- block, bsize);
- if (buffer->error) {
- ERROR("Unable to read page, block %llx, size %x"
- "\n", block, bsize);
- squashfs_cache_put(buffer);
- goto error_out;
- }
- bytes = buffer->length;
- }
- } else {
- /*
- * Datablock is stored inside a fragment (tail-end packed
- * block).
- */
- buffer = squashfs_get_fragment(inode->i_sb,
- squashfs_i(inode)->fragment_block,
- squashfs_i(inode)->fragment_size);
-
- if (buffer->error) {
- ERROR("Unable to read page, block %llx, size %x\n",
- squashfs_i(inode)->fragment_block,
- squashfs_i(inode)->fragment_size);
- squashfs_cache_put(buffer);
- goto error_out;
- }
- bytes = i_size_read(inode) & (msblk->block_size - 1);
- offset = squashfs_i(inode)->fragment_offset;
- }
+ int i, mask = (1 << (msblk->block_log - PAGE_CACHE_SHIFT)) - 1;
+ int start_index = page->index & ~mask, end_index = start_index | mask;
/*
* Loop copying datablock into pages. As the datablock likely covers
@@ -451,7 +389,7 @@ static int squashfs_readpage(struct file *file, struct page *page)
for (i = start_index; i <= end_index && bytes > 0; i++,
bytes -= PAGE_CACHE_SIZE, offset += PAGE_CACHE_SIZE) {
struct page *push_page;
- int avail = sparse ? 0 : min_t(int, bytes, PAGE_CACHE_SIZE);
+ int avail = buffer ? min_t(int, bytes, PAGE_CACHE_SIZE) : 0;
TRACE("bytes %d, i %d, available_bytes %d\n", bytes, i, avail);
@@ -475,11 +413,75 @@ skip_page:
if (i != page->index)
page_cache_release(push_page);
}
+}
+
+/* Read datablock stored packed inside a fragment (tail-end packed block) */
+static int squashfs_readpage_fragment(struct page *page)
+{
+ struct inode *inode = page->mapping->host;
+ struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
+ struct squashfs_cache_entry *buffer = squashfs_get_fragment(inode->i_sb,
+ squashfs_i(inode)->fragment_block,
+ squashfs_i(inode)->fragment_size);
+ int res = buffer->error;
+
+ if (res)
+ ERROR("Unable to read page, block %llx, size %x\n",
+ squashfs_i(inode)->fragment_block,
+ squashfs_i(inode)->fragment_size);
+ else
+ squashfs_copy_cache(page, buffer, i_size_read(inode) &
+ (msblk->block_size - 1),
+ squashfs_i(inode)->fragment_offset);
+
+ squashfs_cache_put(buffer);
+ return res;
+}
- if (!sparse)
- squashfs_cache_put(buffer);
+static int squashfs_readpage_sparse(struct page *page, int index, int file_end)
+{
+ struct inode *inode = page->mapping->host;
+ struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
+ int bytes = index == file_end ?
+ (i_size_read(inode) & (msblk->block_size - 1)) :
+ msblk->block_size;
+ squashfs_copy_cache(page, NULL, bytes, 0);
return 0;
+}
+
+static int squashfs_readpage(struct file *file, struct page *page)
+{
+ struct inode *inode = page->mapping->host;
+ struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
+ int index = page->index >> (msblk->block_log - PAGE_CACHE_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);
+
+ if (page->index >= ((i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
+ PAGE_CACHE_SHIFT))
+ goto out;
+
+ 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;
+
+ if (bsize == 0)
+ res = squashfs_readpage_sparse(page, index, file_end);
+ else
+ res = squashfs_readpage_block(page, block, bsize);
+ } else
+ res = squashfs_readpage_fragment(page);
+
+ if (!res)
+ return 0;
error_out:
SetPageError(page);
diff --git a/fs/squashfs/file_cache.c b/fs/squashfs/file_cache.c
new file mode 100644
index 0000000..f2310d2
--- /dev/null
+++ b/fs/squashfs/file_cache.c
@@ -0,0 +1,38 @@
+/*
+ * 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"
+
+/* 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;
+}
diff --git a/fs/squashfs/squashfs.h b/fs/squashfs/squashfs.h
index 6a97e63..9e1bb79 100644
--- a/fs/squashfs/squashfs.h
+++ b/fs/squashfs/squashfs.h
@@ -66,6 +66,13 @@ extern int squashfs_frag_lookup(struct super_block *, unsigned int, u64 *);
extern __le64 *squashfs_read_fragment_index_table(struct super_block *,
u64, u64, unsigned int);
+/* file.c */
+void squashfs_copy_cache(struct page *, struct squashfs_cache_entry *, int,
+ int);
+
+/* file_xxx.c */
+extern int squashfs_readpage_block(struct page *, u64, int);
+
/* id.c */
extern int squashfs_get_id(struct super_block *, unsigned int, unsigned int *);
extern __le64 *squashfs_read_id_index_table(struct super_block *, u64, u64,
--
1.8.3.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 3/3] Squashfs: Directly decompress into the page cache for file data
2013-10-11 6:19 [PATCH 0/3] Squashfs: Directly decompress into the page cache for file data Phillip Lougher
2013-10-11 6:19 ` [PATCH 1/3] Squashfs: Generalise paging handling in the decompressors Phillip Lougher
2013-10-11 6:19 ` [PATCH 2/3] Squashfs: restructure squashfs_readpage() Phillip Lougher
@ 2013-10-11 6:19 ` Phillip Lougher
2013-10-14 1:43 ` Minchan Kim
2013-10-11 8:03 ` [PATCH 0/3] " Minchan Kim
3 siblings, 1 reply; 6+ messages in thread
From: Phillip Lougher @ 2013-10-11 6:19 UTC (permalink / raw)
To: linux-kernel; +Cc: minchan, Phillip Lougher
This introduces an implementation of squashfs_readpage_block()
that directly decompresses into the page cache.
This uses the previously added page handler abstraction to push
down the necessary kmap_atomic/kunmap_atomic operations on the
page cache buffers into the decompressors. This enables
direct copying into the page cache without using the slow
kmap/kunmap calls.
The code detects when multiple threads are racing in
squashfs_readpage() to decompress the same block, and avoids
this regression by falling back to using an intermediate
buffer.
This patch enhances the performance of Squashfs significantly
when multiple processes are accessing the filesystem simultaneously
because it not only reduces memcopying, but it more importantly
eliminates the lock contention on the intermediate buffer.
Using single-thread decompression.
dd if=file1 of=/dev/null bs=4096 &
dd if=file2 of=/dev/null bs=4096 &
dd if=file3 of=/dev/null bs=4096 &
dd if=file4 of=/dev/null bs=4096
Before:
629145600 bytes (629 MB) copied, 45.8046 s, 13.7 MB/s
After:
629145600 bytes (629 MB) copied, 9.29414 s, 67.7 MB/s
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
---
fs/squashfs/Kconfig | 14 ++++
fs/squashfs/Makefile | 7 +-
fs/squashfs/file_direct.c | 178 ++++++++++++++++++++++++++++++++++++++++++++++
fs/squashfs/page_actor.c | 104 +++++++++++++++++++++++++++
fs/squashfs/page_actor.h | 32 +++++++++
5 files changed, 334 insertions(+), 1 deletion(-)
create mode 100644 fs/squashfs/file_direct.c
create mode 100644 fs/squashfs/page_actor.c
diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
index c70111e..8bc9e6a 100644
--- a/fs/squashfs/Kconfig
+++ b/fs/squashfs/Kconfig
@@ -25,6 +25,20 @@ config SQUASHFS
If unsure, say N.
+config SQUASHFS_FILE_DIRECT
+ bool "Decompress files directly into the page cache"
+ depends on SQUASHFS
+ help
+ Squashfs has traditionally decompressed file data into an
+ intermediate buffer and then memcopied it into the page cache.
+
+ Saying Y here includes support for directly decompressing
+ file data into the page cache. Doing so can significantly
+ improve performance because it eliminates a mempcpy and
+ it also removes the lock contention on the single buffer.
+
+ If unsure, say N.
+
config SQUASHFS_XATTR
bool "Squashfs XATTR support"
depends on SQUASHFS
diff --git a/fs/squashfs/Makefile b/fs/squashfs/Makefile
index 14cfc41..deaabc5 100644
--- a/fs/squashfs/Makefile
+++ b/fs/squashfs/Makefile
@@ -5,8 +5,13 @@
obj-$(CONFIG_SQUASHFS) += squashfs.o
squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
squashfs-y += namei.o super.o symlink.o decompressor.o decompressor_single.o
-squashfs-y += file_cache.o
squashfs-$(CONFIG_SQUASHFS_XATTR) += xattr.o xattr_id.o
squashfs-$(CONFIG_SQUASHFS_LZO) += lzo_wrapper.o
squashfs-$(CONFIG_SQUASHFS_XZ) += xz_wrapper.o
squashfs-$(CONFIG_SQUASHFS_ZLIB) += zlib_wrapper.o
+
+ifdef CONFIG_SQUASHFS_FILE_DIRECT
+ squashfs-y += file_direct.o page_actor.o
+else
+ squashfs-y += file_cache.o
+endif
diff --git a/fs/squashfs/file_direct.c b/fs/squashfs/file_direct.c
new file mode 100644
index 0000000..f31298e
--- /dev/null
+++ b/fs/squashfs/file_direct.c
@@ -0,0 +1,178 @@
+/*
+ * 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)
+ goto error_out;
+
+ /*
+ * 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 error_out2;
+
+ /* 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 - probably because we're
+ * racing with another thread in squashfs_readpage also
+ * trying to grab them. Fall back to using an intermediate
+ * buffer. Note as this page conflict is mutual, we
+ * know all the racing processes will do this.
+ */
+ kfree(actor);
+ return squashfs_read_cache(target_page, block, bsize, pages,
+ page);
+ }
+
+ /* 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;
+ pageaddr = kmap_atomic(page[i]);
+ memset(pageaddr, 0, PAGE_CACHE_SIZE);
+ kunmap_atomic(pageaddr);
+ flush_dcache_page(page[i]);
+ SetPageError(page[i]);
+ unlock_page(page[i]);
+ page_cache_release(page[i]);
+ }
+
+ kfree(actor);
+error_out2:
+ kfree(page);
+error_out:
+ 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);
+ kfree(page);
+ return res;
+}
diff --git a/fs/squashfs/page_actor.c b/fs/squashfs/page_actor.c
new file mode 100644
index 0000000..8e754ff
--- /dev/null
+++ b/fs/squashfs/page_actor.c
@@ -0,0 +1,104 @@
+/*
+ * 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"
+
+/* 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;
+
+ if (length)
+ actor->length = length;
+ else
+ actor->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);
+
+ if (actor->next_page == actor->pages) {
+ actor->pageaddr = NULL;
+ return NULL;
+ }
+
+ return actor->pageaddr = 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;
+
+ if (length)
+ actor->length = length;
+ else
+ actor->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 19a66a3..22731c7 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;
@@ -51,4 +52,35 @@ 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
--
1.8.3.2
^ permalink raw reply related [flat|nested] 6+ messages in thread