Phillip Lougher <phillip.lougher@xxxxxxxxx> writes:
> A couple of specific comments...
>
> +/* A backend is initialized for each SquashFS block read operation,
> + * making further sequential reads possible from the block.
> + */
> +static void *bdev_init(struct squashfs_sb_info *msblk, u64 index,
> size_t length)
> +{
> + struct squashfs_bdev *bdev = msblk->backend_data;
> + struct buffer_head *bh;
> +
> + bh = kcalloc((msblk->block_size >> bdev->devblksize_log2) + 1,
> + sizeof(*bh), GFP_KERNEL);
>
> You should alloc against the larger of msblk->block_size and
> METADATA_SIZE (8 Kbytes). Block_size could be 4 Kbytes only.
I plugged in a max(). Couldn't that trailing +1 be converted into a +2
like this?
bh = kcalloc((max(msblk->block_size, METADATA_SIZE) + 2) >> bdev->devblksize_log2
> +static int fill_bdev_super(struct super_block *sb, void *data, int silent)
>
> This function looks rather 'back-to-front' to me. I'm assuming that
> squashfs_fill_super2() will be the current fill superblock function?
> This function wants to read data off the filesystem through the
> backend, and yet the backend (bdev, mblk->backend_data) hasn't been
> initialised when it's called...
I solved it by introducing a callback function for adding the backend.
That may be overkill, but it seems to give the most shared code.
The attached patch series survived some testing here. My only doubt:
the current backend interface necessitates a memory copy from the buffer
heads. This is no problem for mtd and lzma which copy the data anyway,
but makes this code less efficient in the bdev+zlib case.
I've got one more patch, which I forgot to export, to pull out the
common logic from the backend init functions back into squashfs_read_data().
With the bdev backend, that entails reading the first block twice in a
row most of the time. This again could be worked around by extending
the backend interface, but I'm not sure if it's worth it.
How does this look like now?
--
Regards,
Feri.
>From 68f194727a9905e01d216918200671140ecbc04e Mon Sep 17 00:00:00 2001
From: Ferenc Wagner <wferi@xxxxxxx>
Date: Thu, 18 Mar 2010 03:12:01 +0100
Subject: [PATCH] squashfs: add backend plugin framework
---
fs/squashfs/Makefile | 3 +-
fs/squashfs/backend.c | 24 +++++++++
fs/squashfs/backend.h | 22 ++++++++
fs/squashfs/bdev.c | 109 ++++++++++++++++++++++++++++++++++++++++++
fs/squashfs/squashfs.h | 9 +++-
fs/squashfs/squashfs_fs_sb.h | 2 +
6 files changed, 167 insertions(+), 2 deletions(-)
create mode 100644 fs/squashfs/backend.c
create mode 100644 fs/squashfs/backend.h
create mode 100644 fs/squashfs/bdev.c
diff --git a/fs/squashfs/Makefile b/fs/squashfs/Makefile
index 45aaefd..0f02891 100644
--- a/fs/squashfs/Makefile
+++ b/fs/squashfs/Makefile
@@ -4,5 +4,6 @@
obj-$(CONFIG_SQUASHFS) += squashfs.o
squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
-squashfs-y += namei.o super.o symlink.o zlib_wrapper.o decompressor.o
+squashfs-y += namei.o super.o symlink.o zlib_wrapper.o decompressor.o backend.o
squashfs-$(CONFIG_SQUASHFS_LZMA) += lzma_wrapper.o
+squashfs-$(CONFIG_BLOCK) += bdev.o
diff --git a/fs/squashfs/backend.c b/fs/squashfs/backend.c
new file mode 100644
index 0000000..4411c60
--- /dev/null
+++ b/fs/squashfs/backend.c
@@ -0,0 +1,24 @@
+#include <linux/fs.h>
+
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+#include "backend.h"
+
+const struct squashfs_backend *backends[] = {
+#ifdef CONFIG_BLOCK
+ &squashfs_bdev_ops,
+#endif
+ NULL
+};
+
+const struct squashfs_backend *
+squashfs_find_backend(struct file_system_type *fs_type, int flags,
+ const char *dev_name, void *data, struct vfsmount *mnt)
+{
+ const struct squashfs_backend **b;
+
+ for (b = backends; *b; b++)
+ if (!(*b)->probe(fs_type, flags, dev_name, data, mnt))
+ break;
+ return *b;
+}
diff --git a/fs/squashfs/backend.h b/fs/squashfs/backend.h
new file mode 100644
index 0000000..ca3ffe1
--- /dev/null
+++ b/fs/squashfs/backend.h
@@ -0,0 +1,22 @@
+#include <linux/fs.h>
+#include <linux/vfs.h>
+
+#include "squashfs_fs_sb.h"
+
+struct squashfs_backend {
+ void *(*init)(struct squashfs_sb_info *, u64, size_t);
+ void (*free)(struct squashfs_sb_info *);
+ ssize_t (*read)(struct squashfs_sb_info *, void **, size_t);
+ int (*probe)(struct file_system_type *, int, const char *,
+ void*, struct vfsmount *);
+ void (*kill)(struct squashfs_sb_info *);
+ loff_t (*size)(const struct super_block *);
+ const char *(*devname)(const struct super_block *, char *);
+};
+
+/* Dummy, until the original is nuked */
+static inline int squashfs_fill_super2(struct super_block *sb, void *data,
+ int silent, int (*add_bend)(struct super_block *))
+{
+ return -1;
+}
diff --git a/fs/squashfs/bdev.c b/fs/squashfs/bdev.c
new file mode 100644
index 0000000..fcc3b83
--- /dev/null
+++ b/fs/squashfs/bdev.c
@@ -0,0 +1,109 @@
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+#include "backend.h"
+
+struct squashfs_bdev {
+ int devblksize; /* FIXME: == s->s_blocksize(_bits)? */
+ unsigned short devblksize_log2;
+ size_t bytes_left;
+ struct buffer_head **bh;
+ int bh_index; /* number of consumed buffer_heads */
+ int offset; /* offset of next byte in buffer_head */
+};
+
+/* A backend is initialized for each SquashFS block read operation,
+ * making further sequential reads possible from the block.
+ */
+static void *bdev_init(struct squashfs_sb_info *msblk, u64 index, size_t length)
+{
+ struct squashfs_bdev *bdev = msblk->backend_data;
+ struct buffer_head *bh;
+
+ bh = kcalloc((max(msblk->block_size, METADATA_SIZE) >> bdev->devblksize_log2) + 1,
+ sizeof(*bh), GFP_KERNEL);
+ if (!bh)
+ goto nomem;
+
+ /* different preread for data blocks and metadata blocks */
+
+ bdev->bh_index = 0;
+ bdev->bytes_left = length;
+ return bdev;
+
+nomem:
+ ERROR("failed to allocate buffer_heads\n");
+ return NULL;
+}
+
+static void bdev_free(struct squashfs_sb_info *msblk)
+{
+ struct squashfs_bdev *bdev = msblk->backend_data;
+ kfree(bdev->bh);
+ bdev->bh = 0; /* FIXME: to make bdev_kill universal (see there) */
+}
+
+static ssize_t bdev_read(struct squashfs_sb_info *msblk, void **buf, size_t len)
+{
+ return -ENOSYS;
+}
+
+static int add_bdev_backend(struct super_block *sb)
+{
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
+ struct squashfs_bdev *bdev = kzalloc(sizeof(*bdev), GFP_KERNEL);
+
+ if (!bdev)
+ return -ENOMEM;
+
+ bdev->devblksize = sb_min_blocksize(sb, BLOCK_SIZE);
+ bdev->devblksize_log2 = ffz(~bdev->devblksize);
+
+ msblk->backend = &squashfs_bdev_ops;
+ msblk->backend_data = bdev;
+ return 0;
+}
+
+static int fill_bdev_super(struct super_block *sb, void *data, int silent)
+{
+ return squashfs_fill_super2(sb, data, silent, add_bdev_backend);
+}
+
+static int bdev_probe(struct file_system_type *fs_type, int flags,
+ const char *dev_name, void *data,
+ struct vfsmount *mnt)
+{
+ return get_sb_bdev(fs_type, flags, dev_name, data,
+ fill_bdev_super, mnt);
+}
+
+static void bdev_kill(struct squashfs_sb_info *msblk)
+{
+ struct squashfs_bdev *bdev = msblk->backend_data;
+ if (bdev) {
+ kfree(bdev->bh); /* FIXME: can this be nonzero? cf. bdev_free */
+ kfree(bdev);
+ }
+}
+
+static loff_t bdev_size(const struct super_block *sb)
+{
+ return i_size_read(sb->s_bdev->bd_inode);
+}
+
+static const char *bdev_devname(const struct super_block *sb, char *buffer)
+{
+ return bdevname(sb->s_bdev, buffer);
+}
+
+const struct squashfs_backend squashfs_bdev_ops = {
+ .init = bdev_init,
+ .free = bdev_free,
+ .read = bdev_read,
+ .probe = bdev_probe,
+ .kill = bdev_kill,
+ .size = bdev_size,
+ .devname= bdev_devname
+};
diff --git a/fs/squashfs/squashfs.h b/fs/squashfs/squashfs.h
index d094886..0e74175 100644
--- a/fs/squashfs/squashfs.h
+++ b/fs/squashfs/squashfs.h
@@ -73,8 +73,12 @@ extern struct inode *squashfs_iget(struct super_block *, long long,
unsigned int);
extern int squashfs_read_inode(struct inode *, long long);
+/* super.c
+int squashfs_fill_super(struct super_block *, void *, int,
+ struct squashfs_backend *);
+*/
/*
- * Inodes, files and decompressor operations
+ * Inodes, files, backend and decompressor operations
*/
/* dir.c */
@@ -97,3 +101,6 @@ extern const struct squashfs_decompressor squashfs_zlib_comp_ops;
/* lzma wrapper.c */
extern const struct squashfs_decompressor squashfs_lzma_comp_ops;
+
+/* bdev.c */
+extern const struct squashfs_backend squashfs_bdev_ops;
diff --git a/fs/squashfs/squashfs_fs_sb.h b/fs/squashfs/squashfs_fs_sb.h
index 7533350..5662d9b 100644
--- a/fs/squashfs/squashfs_fs_sb.h
+++ b/fs/squashfs/squashfs_fs_sb.h
@@ -53,6 +53,8 @@ struct squashfs_cache_entry {
struct squashfs_sb_info {
const struct squashfs_decompressor *decompressor;
+ const struct squashfs_backend *backend;
+ void *backend_data;
int devblksize;
int devblksize_log2;
struct squashfs_cache *block_cache;
--
1.5.6.5
>From 7f3d85818017d128cc438fefdf300f770dd7869e Mon Sep 17 00:00:00 2001
From: Ferenc Wagner <wferi@xxxxxxx>
Date: Sat, 20 Mar 2010 15:58:21 +0100
Subject: [PATCH] squashfs: thread initialization through the backend framework
This necessitated introducing the killsb callback.
The read path is still untouched.
---
fs/squashfs/backend.c | 22 +++++++++++++++-----
fs/squashfs/backend.h | 11 ++++-----
fs/squashfs/bdev.c | 3 +-
fs/squashfs/squashfs.h | 6 ++--
fs/squashfs/super.c | 49 +++++++++++++++++++++--------------------------
5 files changed, 48 insertions(+), 43 deletions(-)
diff --git a/fs/squashfs/backend.c b/fs/squashfs/backend.c
index 4411c60..49fa6fa 100644
--- a/fs/squashfs/backend.c
+++ b/fs/squashfs/backend.c
@@ -11,14 +11,24 @@ const struct squashfs_backend *backends[] = {
NULL
};
-const struct squashfs_backend *
-squashfs_find_backend(struct file_system_type *fs_type, int flags,
+int squashfs_find_backend(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data, struct vfsmount *mnt)
{
const struct squashfs_backend **b;
+ int err;
- for (b = backends; *b; b++)
- if (!(*b)->probe(fs_type, flags, dev_name, data, mnt))
- break;
- return *b;
+ for (b = backends; *b; b++) {
+ err = (*b)->probe(fs_type, flags, dev_name, data, mnt);
+ if (!err)
+ return 0;
+ }
+ ERROR("No suitable backend found\n");
+ return -ENODEV;
+}
+
+void squashfs_kill_super(struct super_block *sb)
+{
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
+
+ msblk->backend->killsb(sb);
}
diff --git a/fs/squashfs/backend.h b/fs/squashfs/backend.h
index ca3ffe1..02c4bcd 100644
--- a/fs/squashfs/backend.h
+++ b/fs/squashfs/backend.h
@@ -9,14 +9,13 @@ struct squashfs_backend {
ssize_t (*read)(struct squashfs_sb_info *, void **, size_t);
int (*probe)(struct file_system_type *, int, const char *,
void*, struct vfsmount *);
+ void (*killsb)(struct super_block *);
void (*kill)(struct squashfs_sb_info *);
loff_t (*size)(const struct super_block *);
const char *(*devname)(const struct super_block *, char *);
};
-/* Dummy, until the original is nuked */
-static inline int squashfs_fill_super2(struct super_block *sb, void *data,
- int silent, int (*add_bend)(struct super_block *))
-{
- return -1;
-}
+int squashfs_find_backend(struct file_system_type *, int,
+ const char *, void *, struct vfsmount *);
+
+void squashfs_kill_super(struct super_block *);
diff --git a/fs/squashfs/bdev.c b/fs/squashfs/bdev.c
index fcc3b83..81652e8 100644
--- a/fs/squashfs/bdev.c
+++ b/fs/squashfs/bdev.c
@@ -68,7 +68,7 @@ static int add_bdev_backend(struct super_block *sb)
static int fill_bdev_super(struct super_block *sb, void *data, int silent)
{
- return squashfs_fill_super2(sb, data, silent, add_bdev_backend);
+ return squashfs_fill_super(sb, data, silent, add_bdev_backend);
}
static int bdev_probe(struct file_system_type *fs_type, int flags,
@@ -103,6 +103,7 @@ const struct squashfs_backend squashfs_bdev_ops = {
.free = bdev_free,
.read = bdev_read,
.probe = bdev_probe,
+ .killsb = kill_block_super,
.kill = bdev_kill,
.size = bdev_size,
.devname= bdev_devname
diff --git a/fs/squashfs/squashfs.h b/fs/squashfs/squashfs.h
index 0e74175..24c4b9e 100644
--- a/fs/squashfs/squashfs.h
+++ b/fs/squashfs/squashfs.h
@@ -73,10 +73,10 @@ extern struct inode *squashfs_iget(struct super_block *, long long,
unsigned int);
extern int squashfs_read_inode(struct inode *, long long);
-/* super.c
+/* super.c */
int squashfs_fill_super(struct super_block *, void *, int,
- struct squashfs_backend *);
-*/
+ int (*)(struct super_block *));
+
/*
* Inodes, files, backend and decompressor operations
*/
diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
index 3550aec..710179f 100644
--- a/fs/squashfs/super.c
+++ b/fs/squashfs/super.c
@@ -42,6 +42,7 @@
#include "squashfs_fs_i.h"
#include "squashfs.h"
#include "decompressor.h"
+#include "backend.h"
static struct file_system_type squashfs_fs_type;
static const struct super_operations squashfs_super_ops;
@@ -73,7 +74,8 @@ static const struct squashfs_decompressor *supported_squashfs_filesystem(short
}
-static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
+int squashfs_fill_super(struct super_block *sb, void *data, int silent,
+ int (*add_backend)(struct super_block *))
{
struct squashfs_sb_info *msblk;
struct squashfs_super_block *sblk = NULL;
@@ -97,11 +99,15 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
sblk = kzalloc(sizeof(*sblk), GFP_KERNEL);
if (sblk == NULL) {
ERROR("Failed to allocate squashfs_super_block\n");
- goto failure;
+ err = -ENOMEM;
+ goto free_msblk;
}
msblk->devblksize = sb_min_blocksize(sb, BLOCK_SIZE);
msblk->devblksize_log2 = ffz(~msblk->devblksize);
+ err = add_backend(sb);
+ if (err)
+ goto free_sblk;
mutex_init(&msblk->read_data_mutex);
mutex_init(&msblk->meta_index_mutex);
@@ -127,7 +133,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
if (sb->s_magic != SQUASHFS_MAGIC) {
if (!silent)
ERROR("Can't find a SQUASHFS superblock on %s\n",
- bdevname(sb->s_bdev, b));
+ msblk->backend->devname(sb, b));
goto failed_mount;
}
@@ -146,11 +152,10 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
if (le64_to_cpu(sblk->xattr_table_start) != SQUASHFS_INVALID_BLK)
ERROR("Xattrs in filesystem, these will be ignored\n");
- /* Check the filesystem does not extend beyond the end of the
- block device */
+ /* Check the filesystem does not extend beyond the end of the device */
msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
if (msblk->bytes_used < 0 || msblk->bytes_used >
- i_size_read(sb->s_bdev->bd_inode))
+ msblk->backend->size(sb))
goto failed_mount;
/* Check block size for sanity */
@@ -182,7 +187,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
msblk->inodes = le32_to_cpu(sblk->inodes);
flags = le16_to_cpu(sblk->flags);
- TRACE("Found valid superblock on %s\n", bdevname(sb->s_bdev, b));
+ TRACE("Found valid superblock on %s\n", msblk->backend->devname(sb, b));
TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
? "un" : "");
TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
@@ -297,18 +302,16 @@ failed_mount:
squashfs_cache_delete(msblk->fragment_cache);
squashfs_cache_delete(msblk->read_page);
squashfs_decompressor_free(msblk, msblk->stream);
- kfree(msblk->inode_lookup_table);
+ kfree(msblk->inode_lookup_table); /* FIXME: squashfs_put_super has meta_index instead */
kfree(msblk->fragment_index);
kfree(msblk->id_table);
- kfree(sb->s_fs_info);
- sb->s_fs_info = NULL;
+ msblk->backend->kill(msblk);
+free_sblk:
kfree(sblk);
- return err;
-
-failure:
- kfree(sb->s_fs_info);
+free_msblk:
+ kfree(msblk);
sb->s_fs_info = NULL;
- return -ENOMEM;
+ return err;
}
@@ -353,7 +356,8 @@ static void squashfs_put_super(struct super_block *sb)
kfree(sbi->id_table);
kfree(sbi->fragment_index);
kfree(sbi->meta_index);
- kfree(sb->s_fs_info);
+ sbi->backend->kill(sbi);
+ kfree(sbi);
sb->s_fs_info = NULL;
}
@@ -361,15 +365,6 @@ static void squashfs_put_super(struct super_block *sb)
}
-static int squashfs_get_sb(struct file_system_type *fs_type, int flags,
- const char *dev_name, void *data,
- struct vfsmount *mnt)
-{
- return get_sb_bdev(fs_type, flags, dev_name, data, squashfs_fill_super,
- mnt);
-}
-
-
static struct kmem_cache *squashfs_inode_cachep;
@@ -442,8 +437,8 @@ static void squashfs_destroy_inode(struct inode *inode)
static struct file_system_type squashfs_fs_type = {
.owner = THIS_MODULE,
.name = "squashfs",
- .get_sb = squashfs_get_sb,
- .kill_sb = kill_block_super,
+ .get_sb = squashfs_find_backend,
+ .kill_sb = squashfs_kill_super,
.fs_flags = FS_REQUIRES_DEV
};
--
1.5.6.5
>From 4b150ae9d6c3ae77b139f75a1466aa10e1ef1b5a Mon Sep 17 00:00:00 2001
From: Ferenc Wagner <wferi@xxxxxxx>
Date: Sun, 21 Mar 2010 02:08:58 +0100
Subject: [PATCH] squashfs: read uncompressed blocks through the backend framework
Avoid double free on the temporary decompression hack-path; this may
leak buffer heads if decompression exits early.
---
fs/squashfs/backend.h | 4 +-
fs/squashfs/bdev.c | 191 ++++++++++++++++++++++++++++++++++++++----
fs/squashfs/block.c | 167 ++++++++-----------------------------
fs/squashfs/lzma_wrapper.c | 2 +
fs/squashfs/squashfs_fs_sb.h | 2 -
fs/squashfs/super.c | 5 +-
6 files changed, 216 insertions(+), 155 deletions(-)
diff --git a/fs/squashfs/backend.h b/fs/squashfs/backend.h
index 02c4bcd..308fe6d 100644
--- a/fs/squashfs/backend.h
+++ b/fs/squashfs/backend.h
@@ -4,9 +4,9 @@
#include "squashfs_fs_sb.h"
struct squashfs_backend {
- void *(*init)(struct squashfs_sb_info *, u64, size_t);
+ int (*init)(struct super_block *, u64, int, int, u64 *, int *);
void (*free)(struct squashfs_sb_info *);
- ssize_t (*read)(struct squashfs_sb_info *, void **, size_t);
+ int (*read)(struct super_block *, void *, int);
int (*probe)(struct file_system_type *, int, const char *,
void*, struct vfsmount *);
void (*killsb)(struct super_block *);
diff --git a/fs/squashfs/bdev.c b/fs/squashfs/bdev.c
index 81652e8..59f79ee 100644
--- a/fs/squashfs/bdev.c
+++ b/fs/squashfs/bdev.c
@@ -8,46 +8,199 @@
struct squashfs_bdev {
int devblksize; /* FIXME: == s->s_blocksize(_bits)? */
unsigned short devblksize_log2;
- size_t bytes_left;
+ int length;
+ int bytes_read;
struct buffer_head **bh;
int bh_index; /* number of consumed buffer_heads */
int offset; /* offset of next byte in buffer_head */
+ int b; /* total number of buffer heads */
};
-/* A backend is initialized for each SquashFS block read operation,
- * making further sequential reads possible from the block.
+/*
+ * Read the metadata block length, this is stored in the first two
+ * bytes of the metadata block.
*/
-static void *bdev_init(struct squashfs_sb_info *msblk, u64 index, size_t length)
+static struct buffer_head *get_block_length(struct super_block *sb,
+ u64 *cur_index, int *offset, int *length)
{
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
struct squashfs_bdev *bdev = msblk->backend_data;
struct buffer_head *bh;
+ TRACE("get_block_length: cur_index=0x%llx, offset=%d\n",
+ (unsigned long long)*cur_index, *offset);
+ bh = sb_bread(sb, *cur_index);
+ if (bh == NULL)
+ return NULL;
+
+ if (bdev->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;
+ }
+
+ TRACE("get_block_length: length=%d, offset=%d\n", *length, *offset);
+ return bh;
+}
+
+/*
+ * Read a metadata block or datablock into memory. Length is non-zero
+ * if a datablock is being read (the size is stored elsewhere in the
+ * filesystem), otherwise the length is obtained from the first two bytes of
+ * the metadata block. A bit in the length field indicates if the block
+ * is stored uncompressed in the filesystem (usually because compression
+ * generated a larger block - this does occasionally happen with zlib).
+ */
+static int bdev_init(struct super_block *sb, u64 index, int length,
+ int srclength, u64 *next_index, int *compressed)
+{
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
+ struct squashfs_bdev *bdev = msblk->backend_data;
+ struct buffer_head **bh;
+ u64 cur_index; /* sector of next byte */
+ int bytes; /* number of bytes handled */
+ int b; /* for counting buffer heads */
+
+ TRACE("Entering bdev_init: index=0x%llx, length=0x%x, srclength=%d\n",
+ index, length, srclength);
bh = kcalloc((max(msblk->block_size, METADATA_SIZE) >> bdev->devblksize_log2) + 1,
sizeof(*bh), GFP_KERNEL);
- if (!bh)
- goto nomem;
+ if (bh == NULL)
+ return -ENOMEM;
+
+ bdev->offset = index & ((1 << bdev->devblksize_log2) - 1);
+ cur_index = index >> bdev->devblksize_log2;
+ if (length) { /* FIXME: this logic and the comment above should be pulled out! */
+ /*
+ * Datablock.
+ */
+ bytes = -bdev->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, srclength);
- /* different preread for data blocks and metadata blocks */
+ if (length < 0 || length > srclength ||
+ (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 += bdev->devblksize;
+ }
+ ll_rw_block(READ, b, bh);
+ } else {
+ /*
+ * Metadata block.
+ */
+ if ((index + 2) > msblk->bytes_used)
+ goto read_failure;
+
+ bh[0] = get_block_length(sb, &cur_index, &bdev->offset, &length);
+ if (bh[0] == NULL)
+ goto read_failure;
+ b = 1;
+
+ bytes = bdev->devblksize - bdev->offset;
+ *compressed = SQUASHFS_COMPRESSED(length);
+ length = SQUASHFS_COMPRESSED_SIZE(length);
+ if (next_index)
+ *next_index = index + length + 2;
+
+ TRACE("Block @ 0x%llx, %scompressed size %d\n", index,
+ *compressed ? "" : "un", length);
+
+ if (length < 0 || length > srclength ||
+ (index + length) > msblk->bytes_used)
+ goto block_release;
+
+ for (; bytes < length; b++) {
+ bh[b] = sb_getblk(sb, ++cur_index);
+ if (bh[b] == NULL)
+ goto block_release;
+ bytes += bdev->devblksize;
+ }
+ ll_rw_block(READ, b - 1, bh + 1);
+ }
+
+ bdev->bh = bh;
+ bdev->length = length;
+ bdev->bytes_read = 0;
+ bdev->b = b;
bdev->bh_index = 0;
- bdev->bytes_left = length;
- return bdev;
+ TRACE("bdev_init: allocated %d buffer heads at %p, returning length=%d",
+ b, bh, length);
+ return length;
-nomem:
- ERROR("failed to allocate buffer_heads\n");
- return NULL;
+block_release:
+ while (b--)
+ put_bh(bh[b]);
+read_failure:
+ ERROR("bdev_init failed to read block 0x%llx\n",
+ (unsigned long long) index);
+ kfree(bh);
+ return -EIO;
}
static void bdev_free(struct squashfs_sb_info *msblk)
{
struct squashfs_bdev *bdev = msblk->backend_data;
+
+ TRACE("bdev_free: bh=%p, bh_index=%d, b=%d\n",
+ bdev->bh, bdev->bh_index, bdev->b);
+ while (bdev->bh_index < bdev->b)
+ put_bh(bdev->bh[bdev->bh_index++]);
kfree(bdev->bh);
- bdev->bh = 0; /* FIXME: to make bdev_kill universal (see there) */
+ bdev->bh = NULL;
}
-static ssize_t bdev_read(struct squashfs_sb_info *msblk, void **buf, size_t len)
+static int bdev_read(struct super_block *sb, void *buf, int len)
{
- return -ENOSYS;
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
+ struct squashfs_bdev *bdev = msblk->backend_data;
+ struct buffer_head *bh = bdev->bh[bdev->bh_index];
+ int in_block = bdev->devblksize - bdev->offset;
+
+ TRACE("bdev_read: buf=%p, len=%d, length=%d, bytes_read=%d, in_block=%d, bh_index=%d, offset=%d\n",
+ buf, len, bdev->length, bdev->bytes_read, in_block, bdev->bh_index, bdev->offset);
+ if (bdev->bytes_read == bdev->length) /* EOF */
+ return 0;
+ if (bdev->bytes_read + len > bdev->length)
+ len = bdev->length - bdev->bytes_read;
+ if (bdev->bytes_read == 0 || bdev->offset == 0) {
+ TRACE("bdev_read: wait_on_buffer %d\n", bdev->bh_index);
+ wait_on_buffer(bh);
+ if (!buffer_uptodate(bh))
+ return -EIO;
+ }
+ if (len < in_block) {
+ TRACE("bdev_read: copying %d bytes", len);
+ memcpy(buf, bh->b_data + bdev->offset, len);
+ bdev->offset += len;
+ bdev->bytes_read += len;
+ return len;
+ } else {
+ TRACE("bdev_read: copying %d bytes", in_block);
+ memcpy(buf, bh->b_data + bdev->offset, in_block);
+ put_bh(bh);
+ bdev->bh_index++;
+ bdev->offset = 0;
+ bdev->bytes_read += in_block;
+ return in_block;
+ }
}
static int add_bdev_backend(struct super_block *sb)
@@ -55,6 +208,7 @@ static int add_bdev_backend(struct super_block *sb)
struct squashfs_sb_info *msblk = sb->s_fs_info;
struct squashfs_bdev *bdev = kzalloc(sizeof(*bdev), GFP_KERNEL);
+ TRACE("add_bdev_backend\n");
if (!bdev)
return -ENOMEM;
@@ -82,9 +236,12 @@ static int bdev_probe(struct file_system_type *fs_type, int flags,
static void bdev_kill(struct squashfs_sb_info *msblk)
{
struct squashfs_bdev *bdev = msblk->backend_data;
+
+ TRACE("bdev_kill: bdev=%p\n", bdev);
if (bdev) {
- kfree(bdev->bh); /* FIXME: can this be nonzero? cf. bdev_free */
+ bdev_free(msblk);
kfree(bdev);
+ bdev = NULL;
}
}
@@ -104,7 +261,7 @@ const struct squashfs_backend squashfs_bdev_ops = {
.read = bdev_read,
.probe = bdev_probe,
.killsb = kill_block_super,
- .kill = bdev_kill,
+ .kill = bdev_kill, /* FIXME: is this needed at all? */
.size = bdev_size,
.devname= bdev_devname
};
diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index 6f9914d..8787aac 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -37,37 +37,19 @@
#include "squashfs_fs_i.h"
#include "squashfs.h"
#include "decompressor.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)
-{
- struct squashfs_sb_info *msblk = sb->s_fs_info;
- struct buffer_head *bh;
-
- 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;
- }
-
- return bh;
-}
-
+#include "backend.h"
+
+/* FIXME: here for a temporary cheat only */
+struct squashfs_bdev {
+ int devblksize; /* FIXME: == s->s_blocksize(_bits)? */
+ unsigned short devblksize_log2;
+ int length;
+ int bytes_read;
+ struct buffer_head **bh;
+ int bh_index; /* number of consumed buffer_heads */
+ int offset; /* offset of next byte in buffer_head */
+ int b; /* total number of buffer heads */
+};
/*
* Read and decompress a metadata block or datablock. Length is non-zero
@@ -80,124 +62,47 @@ static struct buffer_head *get_block_length(struct super_block *sb,
int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
int length, u64 *next_index, int srclength, int pages)
{
+ int compressed;
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;
-
-
- bh = kcalloc((msblk->block_size >> msblk->devblksize_log2) + 1,
- sizeof(*bh), GFP_KERNEL);
- if (bh == NULL)
- 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, srclength);
- if (length < 0 || length > srclength ||
- (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(READ, 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;
-
- TRACE("Block @ 0x%llx, %scompressed size %d\n", index,
- compressed ? "" : "un", length);
-
- if (length < 0 || length > srclength ||
- (index + length) > msblk->bytes_used)
- goto block_release;
-
- for (; bytes < length; b++) {
- bh[b] = sb_getblk(sb, ++cur_index);
- if (bh[b] == NULL)
- goto block_release;
- bytes += msblk->devblksize;
- }
- ll_rw_block(READ, b - 1, bh + 1);
- }
+ length = msblk->backend->init(sb, index, length, srclength,
+ next_index, &compressed);
+ if (length < 0)
+ return length;
if (compressed) {
- length = squashfs_decompress(msblk, buffer, bh, b, offset,
- length, srclength, pages);
+ struct squashfs_bdev *bdev = msblk->backend_data;
+ length = squashfs_decompress(msblk, buffer, bdev->bh, bdev->b,
+ bdev->offset, length, srclength, pages);
+ bdev->bh_index = bdev->b; /* temporary hack to avoid double free */
if (length < 0)
goto read_failure;
} else {
/*
* Block is uncompressed.
*/
- int i, in, pg_offset = 0;
-
- for (i = 0; i < b; i++) {
- wait_on_buffer(bh[i]);
- if (!buffer_uptodate(bh[i]))
- goto block_release;
- }
-
- for (bytes = length; k < b; k++) {
- in = min(bytes, msblk->devblksize - offset);
- bytes -= in;
- while (in) {
- if (pg_offset == PAGE_CACHE_SIZE) {
- page++;
- pg_offset = 0;
- }
- avail = min_t(int, in, PAGE_CACHE_SIZE -
- pg_offset);
- memcpy(buffer[page] + pg_offset,
- bh[k]->b_data + offset, avail);
- in -= avail;
- pg_offset += avail;
- offset += avail;
+ int read, page = 0, pg_offset = 0;
+
+ while ((read = msblk->backend->read(sb, buffer[page] + pg_offset,
+ PAGE_CACHE_SIZE - pg_offset))) {
+ if (read < 0)
+ goto read_failure;
+ TRACE("copied %d bytes\n", read);
+ pg_offset += read;
+ if (pg_offset == PAGE_CACHE_SIZE) {
+ page++;
+ pg_offset = 0;
}
- offset = 0;
- put_bh(bh[k]);
}
}
- kfree(bh);
+ msblk->backend->free(msblk);
+ TRACE("squashfs_read_data: returning length=%d\n", length);
return length;
-block_release:
- for (; k < b; k++)
- put_bh(bh[k]);
-
read_failure:
ERROR("squashfs_read_data failed to read block 0x%llx\n",
(unsigned long long) index);
- kfree(bh);
+ msblk->backend->free(msblk);
return -EIO;
}
diff --git a/fs/squashfs/lzma_wrapper.c b/fs/squashfs/lzma_wrapper.c
index 9fa617d..439798f 100644
--- a/fs/squashfs/lzma_wrapper.c
+++ b/fs/squashfs/lzma_wrapper.c
@@ -94,6 +94,8 @@ static int lzma_uncompress(struct squashfs_sb_info *msblk, void **buffer,
void *buff = stream->input;
int avail, i, bytes = length, res;
+ TRACE("lzma_uncompress: bh=%p, b=%d, offset=%d, length=%d, srclength=%d,"
+ " pages=%d\n", bh, b, offset, length, srclength, pages);
mutex_lock(&lzma_mutex);
for (i = 0; i < b; i++) {
diff --git a/fs/squashfs/squashfs_fs_sb.h b/fs/squashfs/squashfs_fs_sb.h
index 5662d9b..87958fc 100644
--- a/fs/squashfs/squashfs_fs_sb.h
+++ b/fs/squashfs/squashfs_fs_sb.h
@@ -55,8 +55,6 @@ struct squashfs_sb_info {
const struct squashfs_decompressor *decompressor;
const struct squashfs_backend *backend;
void *backend_data;
- int devblksize;
- int devblksize_log2;
struct squashfs_cache *block_cache;
struct squashfs_cache *fragment_cache;
struct squashfs_cache *read_page;
diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
index 710179f..cb561bf 100644
--- a/fs/squashfs/super.c
+++ b/fs/squashfs/super.c
@@ -87,7 +87,7 @@ int squashfs_fill_super(struct super_block *sb, void *data, int silent,
u64 lookup_table_start;
int err;
- TRACE("Entered squashfs_fill_superblock\n");
+ TRACE("Entered squashfs_fill_superblock, silent=%d\n", silent);
sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
if (sb->s_fs_info == NULL) {
@@ -103,8 +103,6 @@ int squashfs_fill_super(struct super_block *sb, void *data, int silent,
goto free_msblk;
}
- msblk->devblksize = sb_min_blocksize(sb, BLOCK_SIZE);
- msblk->devblksize_log2 = ffz(~msblk->devblksize);
err = add_backend(sb);
if (err)
goto free_sblk;
@@ -305,6 +303,7 @@ failed_mount:
kfree(msblk->inode_lookup_table); /* FIXME: squashfs_put_super has meta_index instead */
kfree(msblk->fragment_index);
kfree(msblk->id_table);
+ TRACE("squasfs_fill_super: killing backend, err=%d\n", err);
msblk->backend->kill(msblk);
free_sblk:
kfree(sblk);
--
1.5.6.5
>From a139798e093314d4fd6fe121a84ae6b30a33af43 Mon Sep 17 00:00:00 2001
From: Ferenc Wagner <wferi@xxxxxxx>
Date: Sun, 21 Mar 2010 22:38:00 +0100
Subject: [PATCH] squashfs: move the decompressors to the backend framework
---
fs/squashfs/block.c | 17 +----------------
fs/squashfs/decompressor.h | 12 +++++-------
fs/squashfs/lzma_wrapper.c | 27 +++++++++------------------
fs/squashfs/zlib_wrapper.c | 44 ++++++++++++++++++--------------------------
4 files changed, 33 insertions(+), 67 deletions(-)
diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index 8787aac..1c85063 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -39,18 +39,6 @@
#include "decompressor.h"
#include "backend.h"
-/* FIXME: here for a temporary cheat only */
-struct squashfs_bdev {
- int devblksize; /* FIXME: == s->s_blocksize(_bits)? */
- unsigned short devblksize_log2;
- int length;
- int bytes_read;
- struct buffer_head **bh;
- int bh_index; /* number of consumed buffer_heads */
- int offset; /* offset of next byte in buffer_head */
- int b; /* total number of buffer heads */
-};
-
/*
* Read and decompress a metadata block or datablock. Length is non-zero
* if a datablock is being read (the size is stored elsewhere in the
@@ -71,10 +59,7 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
return length;
if (compressed) {
- struct squashfs_bdev *bdev = msblk->backend_data;
- length = squashfs_decompress(msblk, buffer, bdev->bh, bdev->b,
- bdev->offset, length, srclength, pages);
- bdev->bh_index = bdev->b; /* temporary hack to avoid double free */
+ length = squashfs_decompress(sb, buffer, length, pages);
if (length < 0)
goto read_failure;
} else {
diff --git a/fs/squashfs/decompressor.h b/fs/squashfs/decompressor.h
index 7425f80..06b4233 100644
--- a/fs/squashfs/decompressor.h
+++ b/fs/squashfs/decompressor.h
@@ -26,8 +26,7 @@
struct squashfs_decompressor {
void *(*init)(struct squashfs_sb_info *);
void (*free)(void *);
- int (*decompress)(struct squashfs_sb_info *, void **,
- struct buffer_head **, int, int, int, int, int);
+ int (*decompress)(struct super_block *, void **, int, int);
int id;
char *name;
int supported;
@@ -45,11 +44,10 @@ static inline void squashfs_decompressor_free(struct squashfs_sb_info *msblk,
msblk->decompressor->free(s);
}
-static inline int squashfs_decompress(struct squashfs_sb_info *msblk,
- void **buffer, struct buffer_head **bh, int b, int offset, int length,
- int srclength, int pages)
+static inline int squashfs_decompress(struct super_block *sb,
+ void **buffer, int length, int pages)
{
- return msblk->decompressor->decompress(msblk, buffer, bh, b, offset,
- length, srclength, pages);
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
+ return msblk->decompressor->decompress(sb, buffer, length, pages);
}
#endif
diff --git a/fs/squashfs/lzma_wrapper.c b/fs/squashfs/lzma_wrapper.c
index 439798f..da571ce 100644
--- a/fs/squashfs/lzma_wrapper.c
+++ b/fs/squashfs/lzma_wrapper.c
@@ -32,6 +32,7 @@
#include "squashfs_fs_i.h"
#include "squashfs.h"
#include "decompressor.h"
+#include "backend.h"
struct squashfs_lzma {
void *input;
@@ -86,29 +87,23 @@ static void lzma_free(void *strm)
}
-static int lzma_uncompress(struct squashfs_sb_info *msblk, void **buffer,
- struct buffer_head **bh, int b, int offset, int length, int srclength,
- int pages)
+static int lzma_uncompress(struct super_block *sb, void **buffer,
+ int length, int pages)
{
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
struct squashfs_lzma *stream = msblk->stream;
void *buff = stream->input;
int avail, i, bytes = length, res;
- TRACE("lzma_uncompress: bh=%p, b=%d, offset=%d, length=%d, srclength=%d,"
- " pages=%d\n", bh, b, offset, length, srclength, pages);
+ TRACE("lzma_uncompress: length=%d, pages=%d\n", length, pages);
mutex_lock(&lzma_mutex);
- for (i = 0; i < b; i++) {
- wait_on_buffer(bh[i]);
- if (!buffer_uptodate(bh[i]))
- goto block_release;
-
- avail = min(bytes, msblk->devblksize - offset);
- memcpy(buff, bh[i]->b_data + offset, avail);
+ while ((avail = msblk->backend->read(sb, buff, length))) {
+ if (avail < 0)
+ goto failed;
+ TRACE("read %d bytes\n", avail);
buff += avail;
bytes -= avail;
- offset = 0;
- put_bh(bh[i]);
}
lzma_error = 0;
@@ -131,10 +126,6 @@ static int lzma_uncompress(struct squashfs_sb_info *msblk, void **buffer,
mutex_unlock(&lzma_mutex);
return res;
-block_release:
- for (; i < b; i++)
- put_bh(bh[i]);
-
failed:
mutex_unlock(&lzma_mutex);
diff --git a/fs/squashfs/zlib_wrapper.c b/fs/squashfs/zlib_wrapper.c
index 4dd70e0..70c7571 100644
--- a/fs/squashfs/zlib_wrapper.c
+++ b/fs/squashfs/zlib_wrapper.c
@@ -31,6 +31,7 @@
#include "squashfs_fs_i.h"
#include "squashfs.h"
#include "decompressor.h"
+#include "backend.h"
static void *zlib_init(struct squashfs_sb_info *dummy)
{
@@ -61,13 +62,18 @@ static void zlib_free(void *strm)
}
-static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
- struct buffer_head **bh, int b, int offset, int length, int srclength,
- int pages)
+static int zlib_uncompress(struct super_block *sb, void **buffer,
+ int length, int pages)
{
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
int zlib_err = 0, zlib_init = 0;
- int avail, bytes, k = 0, page = 0;
+ int bytes, page = 0;
z_stream *stream = msblk->stream;
+ /* Copying is required by the backend interface for now. */
+ void *input = kmalloc (PAGE_CACHE_SIZE, GFP_KERNEL);
+
+ if (!input)
+ return -ENOMEM;
mutex_lock(&msblk->read_data_mutex);
@@ -76,22 +82,13 @@ static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
bytes = length;
do {
- if (stream->avail_in == 0 && k < b) {
- avail = min(bytes, msblk->devblksize - offset);
- bytes -= avail;
- wait_on_buffer(bh[k]);
- if (!buffer_uptodate(bh[k]))
+ if (stream->avail_in == 0) {
+ stream->avail_in = msblk->backend->read(sb, input, PAGE_CACHE_SIZE);
+ if (!stream->avail_in) {
+ ERROR("unexpected end of input\n");
goto release_mutex;
-
- if (avail == 0) {
- offset = 0;
- put_bh(bh[k++]);
- continue;
}
-
- stream->next_in = bh[k]->b_data + offset;
- stream->avail_in = avail;
- offset = 0;
+ stream->next_in = input;
}
if (stream->avail_out == 0 && page < pages) {
@@ -103,8 +100,7 @@ static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
zlib_err = zlib_inflateInit(stream);
if (zlib_err != Z_OK) {
ERROR("zlib_inflateInit returned unexpected "
- "result 0x%x, srclength %d\n",
- zlib_err, srclength);
+ "result 0x%x\n", zlib_err);
goto release_mutex;
}
zlib_init = 1;
@@ -112,8 +108,6 @@ static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);
- if (stream->avail_in == 0 && k < b)
- put_bh(bh[k++]);
} while (zlib_err == Z_OK);
if (zlib_err != Z_STREAM_END) {
@@ -128,14 +122,12 @@ static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
}
mutex_unlock(&msblk->read_data_mutex);
+ kfree(input);
return stream->total_out;
release_mutex:
mutex_unlock(&msblk->read_data_mutex);
-
- for (; k < b; k++)
- put_bh(bh[k]);
-
+ kfree(input);
return -EIO;
}
--
1.5.6.5
>From d04e9006614dceb61f26ed462d4e0682de0b31af Mon Sep 17 00:00:00 2001
From: Ferenc Wagner <wferi@xxxxxxx>
Date: Tue, 23 Mar 2010 02:21:27 +0100
Subject: [PATCH] squashfs: add mtd backend
---
fs/squashfs/Kconfig | 2 +-
fs/squashfs/Makefile | 1 +
fs/squashfs/backend.c | 3 +
fs/squashfs/mtd.c | 167 ++++++++++++++++++++++++++++++++++++++++++++++++
fs/squashfs/squashfs.h | 3 +
5 files changed, 175 insertions(+), 1 deletions(-)
create mode 100644 fs/squashfs/mtd.c
diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
index 7ec5d7e..6849e70 100644
--- a/fs/squashfs/Kconfig
+++ b/fs/squashfs/Kconfig
@@ -1,6 +1,6 @@
config SQUASHFS
tristate "SquashFS 4.0 - Squashed file system support"
- depends on BLOCK
+ depends on BLOCK || MTD
select ZLIB_INFLATE
help
Saying Y here includes support for SquashFS 4.0 (a Compressed
diff --git a/fs/squashfs/Makefile b/fs/squashfs/Makefile
index 0f02891..b6dd60e 100644
--- a/fs/squashfs/Makefile
+++ b/fs/squashfs/Makefile
@@ -7,3 +7,4 @@ 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 zlib_wrapper.o decompressor.o backend.o
squashfs-$(CONFIG_SQUASHFS_LZMA) += lzma_wrapper.o
squashfs-$(CONFIG_BLOCK) += bdev.o
+squashfs-$(CONFIG_MTD) += mtd.o
diff --git a/fs/squashfs/backend.c b/fs/squashfs/backend.c
index 49fa6fa..56037e3 100644
--- a/fs/squashfs/backend.c
+++ b/fs/squashfs/backend.c
@@ -8,6 +8,9 @@ const struct squashfs_backend *backends[] = {
#ifdef CONFIG_BLOCK
&squashfs_bdev_ops,
#endif
+#ifdef CONFIG_MTD
+ &squashfs_mtd_ops,
+#endif
NULL
};
diff --git a/fs/squashfs/mtd.c b/fs/squashfs/mtd.c
new file mode 100644
index 0000000..c9ba361
--- /dev/null
+++ b/fs/squashfs/mtd.c
@@ -0,0 +1,167 @@
+#include <linux/fs.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/super.h>
+
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+#include "backend.h"
+
+struct squashfs_mtd {
+ u64 index;
+ int length;
+ int bytes_read;
+};
+
+static int checked_mtd_read(struct super_block *sb, u64 index, int length,
+ void *buf)
+{
+ struct mtd_info *mi = sb->s_mtd;
+ int ret, retlen;
+
+ TRACE("Entering checked_mtd_read: index=0x%llx, length=%d\n",
+ index, length);
+ ret = mi->read(mi, index, length, &retlen, buf);
+ if (ret) {
+ if (ret != -EUCLEAN && ret != -EBADMSG) {
+ ERROR("checked_mtd_read(index=0x%llx, length=%d): %d\n",
+ index, length, ret);
+ return ret;
+ } else
+ WARNING("checked_mtd_read(index=0x%llx, length=%d): "
+ "recoverable error %d\n", index, length, ret);
+ }
+ if (retlen != length) {
+ ERROR("checked_mtd_read(index=0x%llx, length=%d) short read: %d\n",
+ index, length, retlen);
+ return -EIO;
+ }
+ return 0;
+}
+
+static int mtd_init(struct super_block *sb, u64 index, int length,
+ int srclength, u64 *next_index, int *compressed)
+{
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
+ struct squashfs_mtd *mtd = msblk->backend_data;
+
+ TRACE("Entering mtd_init: index=0x%llx, length=0x%x, srclength=%d\n",
+ index, length, srclength);
+
+ if (length) { /* datablock */
+ *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, srclength);
+ } else { /* metadata block */
+ u16 metalen;
+ if ((index + 2) > msblk->bytes_used)
+ goto read_failure;
+ if (checked_mtd_read(sb, index, 2, &metalen))
+ goto read_failure;
+ length = le16_to_cpu(metalen);
+ *compressed = SQUASHFS_COMPRESSED(length);
+ length = SQUASHFS_COMPRESSED_SIZE(length);
+ if (next_index)
+ *next_index = index + length + 2;
+ TRACE("Block @ 0x%llx, %scompressed size %d\n", index,
+ *compressed ? "" : "un", length);
+ index += 2;
+ }
+ if (length < 0 || length > srclength ||
+ (index + length) > msblk->bytes_used)
+ goto read_failure;
+
+ mtd->index = index;
+ mtd->length = length;
+ mtd->bytes_read = 0;
+ return length;
+
+read_failure:
+ ERROR("mtd_init failed to read block 0x%llx\n",
+ (unsigned long long) index);
+ return -EIO;
+}
+
+static void mtd_free(struct squashfs_sb_info *msblk)
+{
+ TRACE("mtd_free: no op\n");
+}
+
+static int mtd_read(struct super_block *sb, void *buf, int len)
+{
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
+ struct squashfs_mtd *mtd = msblk->backend_data;
+ int err;
+
+ TRACE("mtd_read: buf=%p, len=%d, length=%d, bytes_read=%d\n",
+ buf, len, mtd->length, mtd->bytes_read);
+
+ if (mtd->bytes_read == mtd->length) /* EOF */
+ return 0;
+ if (mtd->bytes_read + len > mtd->length)
+ len = mtd->length - mtd->bytes_read;
+ TRACE("mtd_read: copying %d bytes", len);
+ err = checked_mtd_read(sb, mtd->index + mtd->bytes_read, len, buf);
+ if (err)
+ return err;
+ mtd->bytes_read += len;
+ return len;
+}
+
+static int add_mtd_backend(struct super_block *sb)
+{
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
+ struct squashfs_mtd *mtd = kzalloc(sizeof(*mtd), GFP_KERNEL);
+
+ TRACE("add_mtd_backend\n");
+ if (!mtd)
+ return -ENOMEM;
+
+ msblk->backend = &squashfs_mtd_ops;
+ msblk->backend_data = mtd;
+ return 0;
+}
+
+static int fill_mtd_super(struct super_block *sb, void *data, int silent)
+{
+ return squashfs_fill_super(sb, data, silent, add_mtd_backend);
+}
+
+static int mtd_probe(struct file_system_type *fs_type, int flags,
+ const char *dev_name, void *data,
+ struct vfsmount *mnt)
+{
+ return get_sb_mtd(fs_type, flags, dev_name, data,
+ fill_mtd_super, mnt);
+}
+
+static void mtd_kill(struct squashfs_sb_info *msblk)
+{
+ TRACE("mtd_kill: mtd=%p\n", msblk->backend_data);
+ mtd_free(msblk);
+ kfree(msblk->backend_data);
+}
+
+static loff_t mtd_size(const struct super_block *sb)
+{
+ return sb->s_mtd->size;
+}
+
+static const char *mtd_devname(const struct super_block *sb, char *buffer)
+{
+ snprintf(buffer, BDEVNAME_SIZE, "MTD%d", sb->s_mtd->index);
+ return buffer;
+}
+
+const struct squashfs_backend squashfs_mtd_ops = {
+ .init = mtd_init,
+ .free = mtd_free,
+ .read = mtd_read,
+ .probe = mtd_probe,
+ .killsb = kill_mtd_super,
+ .kill = mtd_kill,
+ .size = mtd_size,
+ .devname= mtd_devname
+};
diff --git a/fs/squashfs/squashfs.h b/fs/squashfs/squashfs.h
index 24c4b9e..fc3a57a 100644
--- a/fs/squashfs/squashfs.h
+++ b/fs/squashfs/squashfs.h
@@ -104,3 +104,6 @@ extern const struct squashfs_decompressor squashfs_lzma_comp_ops;
/* bdev.c */
extern const struct squashfs_backend squashfs_bdev_ops;
+
+/* mtd.c */
+extern const struct squashfs_backend squashfs_mtd_ops;
--
1.5.6.5
