[PATCH] squashfs: pull out common logic of backend init functions
Ferenc Wagner
wferi at niif.hu
Tue Mar 23 05:21:40 EDT 2010
---
fs/squashfs/backend.h | 2 +-
fs/squashfs/bdev.c | 155 +++++++++----------------------------------------
fs/squashfs/block.c | 33 ++++++++++-
fs/squashfs/mtd.c | 38 +-----------
4 files changed, 62 insertions(+), 166 deletions(-)
diff --git a/fs/squashfs/backend.h b/fs/squashfs/backend.h
index 308fe6d..5beba00 100644
--- a/fs/squashfs/backend.h
+++ b/fs/squashfs/backend.h
@@ -4,7 +4,7 @@
#include "squashfs_fs_sb.h"
struct squashfs_backend {
- int (*init)(struct super_block *, u64, int, int, u64 *, int *);
+ int (*init)(struct super_block *, u64, int);
void (*free)(struct squashfs_sb_info *);
int (*read)(struct super_block *, void *, int);
int (*probe)(struct file_system_type *, int, const char *,
diff --git a/fs/squashfs/bdev.c b/fs/squashfs/bdev.c
index 497029b..20065b7 100644
--- a/fs/squashfs/bdev.c
+++ b/fs/squashfs/bdev.c
@@ -16,156 +16,55 @@ struct squashfs_bdev {
int b; /* total number of buffer heads */
};
-/*
- * 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 void bdev_free(struct squashfs_sb_info *msblk)
{
- 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;
+ 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 = NULL;
}
-/*
- * 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)
+static int bdev_init(struct super_block *sb, u64 index, int length)
{
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_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE)
- >> bdev->devblksize_log2) + 1,
- sizeof(*bh), GFP_KERNEL);
- if (bh == NULL)
+ TRACE("Entering bdev_init: index=0x%llx, length=0x%x\n",
+ index, length);
+ bdev->bh = kcalloc((max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE)
+ >> bdev->devblksize_log2) + 1,
+ sizeof(*bdev->bh), GFP_KERNEL);
+ if (bdev->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);
-
- 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;
+ bdev->bh_index = 0;
+ bdev->length = length;
+ bdev->bytes_read = 0;
- for (; bytes < length; b++) {
- bh[b] = sb_getblk(sb, ++cur_index);
- if (bh[b] == NULL)
- goto block_release;
- bytes += bdev->devblksize;
+ bytes = -bdev->offset;
+ for (bdev->b = 0; bytes < length; bdev->b++, cur_index++) {
+ if ((bdev->bh[bdev->b] = sb_getblk(sb, cur_index)) == NULL) {
+ ERROR("bdev_init failed to read block 0x%llx\n",
+ (unsigned long long) index);
+ bdev_free(msblk);
+ return -EIO;
}
- ll_rw_block(READ, b - 1, bh + 1);
+ bytes += bdev->devblksize;
}
+ ll_rw_block(READ, bdev->b, bdev->bh);
- bdev->bh = bh;
- bdev->length = length;
- bdev->bytes_read = 0;
- bdev->b = b;
- bdev->bh_index = 0;
TRACE("bdev_init: allocated %d buffer heads at %p, returning length=%d",
- b, bh, length);
+ bdev->b, bdev->bh, length);
return length;
-
-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 = NULL;
}
static int bdev_read(struct super_block *sb, void *buf, int len)
diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index 1c85063..eb33770 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -53,8 +53,37 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
int compressed;
struct squashfs_sb_info *msblk = sb->s_fs_info;
- length = msblk->backend->init(sb, index, length, srclength,
- next_index, &compressed);
+ if (length) { /* Data block */
+ compressed = SQUASHFS_COMPRESSED_BLOCK(length);
+ length = SQUASHFS_COMPRESSED_SIZE_BLOCK(length);
+ TRACE("Block @ 0x%llx, %scompressed size %d, src size %d\n",
+ index, compressed ? "" : "un", length, srclength);
+ } else { /* Metadata block */
+ int read;
+ u16 metalen;
+
+ length = msblk->backend->init(sb, index, 2);
+ if (length < 0)
+ return length;
+ read = msblk->backend->read(sb, &metalen, 2);
+ if (read != 2)
+ goto read_failure;
+ msblk->backend->free(msblk);
+ length = le16_to_cpu(metalen);
+ compressed = SQUASHFS_COMPRESSED(length);
+ length = SQUASHFS_COMPRESSED_SIZE(length);
+ index += 2;
+ TRACE("Block @ 0x%llx, %scompressed size %d\n", index,
+ compressed ? "" : "un", length);
+ }
+ if (length < 0 || length > srclength ||
+ (index + length) > msblk->bytes_used)
+ goto read_failure;
+
+ if (next_index)
+ *next_index = index + length;
+
+ length = msblk->backend->init(sb, index, length);
if (length < 0)
return length;
diff --git a/fs/squashfs/mtd.c b/fs/squashfs/mtd.c
index c9ba361..99f2d35 100644
--- a/fs/squashfs/mtd.c
+++ b/fs/squashfs/mtd.c
@@ -38,50 +38,18 @@ static int checked_mtd_read(struct super_block *sb, u64 index, int length,
return 0;
}
-static int mtd_init(struct super_block *sb, u64 index, int length,
- int srclength, u64 *next_index, int *compressed)
+static int mtd_init(struct super_block *sb, u64 index, int length)
{
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;
+ TRACE("Entering mtd_init: index=0x%llx, length=0x%x\n",
+ index, length);
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)
--
1.5.6.5
--=-=-=--
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