fs: Create a common fs_devread for ext4/reiserfs/zfs

The ext4, reiserfs and zfs filesystems all have their own implementation
of the same function, *_devread. Generalize this function into fs_devread
and put the code into fs/fs_internal.c.

Signed-off-by: Marek Behun <marek.behun@nic.cz>
[trini: Move fs/fs_internal.o hunk to the end of fs/Makefile as all
cases need it]
Signed-off-by: Tom Rini <trini@konsulko.com>

5 files changed, 105 insertions, 236 deletions

diff --git a/fs/Makefile b/fs/Makefile
index 5770f41c0b..b53c9d7cca 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -23,3 +23,4 @@ obj-$(CONFIG_CMD_UBIFS) += ubifs/
 obj-$(CONFIG_YAFFS2) += yaffs2/
 obj-$(CONFIG_CMD_ZFS) += zfs/
 endif
+obj-y += fs_internal.o
diff --git a/fs/ext4/dev.c b/fs/ext4/dev.c
index ae2ba6a901..f04fa08f64 100644
--- a/fs/ext4/dev.c
+++ b/fs/ext4/dev.c
@@ -26,7 +26,7 @@
 #include <common.h>
 #include <blk.h>
 #include <config.h>
-#include <memalign.h>
+#include <fs_internal.h>
 #include <ext4fs.h>
 #include <ext_common.h>
 #include "ext4_common.h"
@@ -47,85 +47,11 @@ void ext4fs_set_blk_dev(struct blk_desc *rbdd, disk_partition_t *info)
 		get_fs()->dev_desc->log2blksz;
 }
 
-int ext4fs_devread(lbaint_t sector, int byte_offset, int byte_len, char *buf)
+int ext4fs_devread(lbaint_t sector, int byte_offset, int byte_len,
+		   char *buffer)
 {
-	unsigned block_len;
-	int log2blksz = ext4fs_blk_desc->log2blksz;
-	ALLOC_CACHE_ALIGN_BUFFER(char, sec_buf, (ext4fs_blk_desc ?
-						 ext4fs_blk_desc->blksz :
-						 0));
-	if (ext4fs_blk_desc == NULL) {
-		printf("** Invalid Block Device Descriptor (NULL)\n");
-		return 0;
-	}
-
-	/* Check partition boundaries */
-	if ((sector + ((byte_offset + byte_len - 1) >> log2blksz))
-	    >= part_info->size) {
-		printf("%s read outside partition " LBAFU "\n", __func__,
-		       sector);
-		return 0;
-	}
-
-	/* Get the read to the beginning of a partition */
-	sector += byte_offset >> log2blksz;
-	byte_offset &= ext4fs_blk_desc->blksz - 1;
-
-	debug(" <" LBAFU ", %d, %d>\n", sector, byte_offset, byte_len);
-
-	if (byte_offset != 0) {
-		int readlen;
-		/* read first part which isn't aligned with start of sector */
-		if (blk_dread(ext4fs_blk_desc, part_info->start + sector, 1,
-			      (void *)sec_buf) != 1) {
-			printf(" ** ext2fs_devread() read error **\n");
-			return 0;
-		}
-		readlen = min((int)ext4fs_blk_desc->blksz - byte_offset,
-			      byte_len);
-		memcpy(buf, sec_buf + byte_offset, readlen);
-		buf += readlen;
-		byte_len -= readlen;
-		sector++;
-	}
-
-	if (byte_len == 0)
-		return 1;
-
-	/* read sector aligned part */
-	block_len = byte_len & ~(ext4fs_blk_desc->blksz - 1);
-
-	if (block_len == 0) {
-		ALLOC_CACHE_ALIGN_BUFFER(u8, p, ext4fs_blk_desc->blksz);
-
-		block_len = ext4fs_blk_desc->blksz;
-		blk_dread(ext4fs_blk_desc, part_info->start + sector, 1,
-			  (void *)p);
-		memcpy(buf, p, byte_len);
-		return 1;
-	}
-
-	if (blk_dread(ext4fs_blk_desc, part_info->start + sector,
-		      block_len >> log2blksz, (void *)buf) !=
-			block_len >> log2blksz) {
-		printf(" ** %s read error - block\n", __func__);
-		return 0;
-	}
-	block_len = byte_len & ~(ext4fs_blk_desc->blksz - 1);
-	buf += block_len;
-	byte_len -= block_len;
-	sector += block_len / ext4fs_blk_desc->blksz;
-
-	if (byte_len != 0) {
-		/* read rest of data which are not in whole sector */
-		if (blk_dread(ext4fs_blk_desc, part_info->start + sector, 1,
-			      (void *)sec_buf) != 1) {
-			printf("* %s read error - last part\n", __func__);
-			return 0;
-		}
-		memcpy(buf, sec_buf, byte_len);
-	}
-	return 1;
+	return fs_devread(get_fs()->dev_desc, part_info, sector, byte_offset,
+			  byte_len, buffer);
 }
 
 int ext4_read_superblock(char *buffer)
diff --git a/fs/fs_internal.c b/fs/fs_internal.c
new file mode 100644
index 0000000000..58b441030c
--- /dev/null
+++ b/fs/fs_internal.c
@@ -0,0 +1,92 @@
+/*
+ * 2017 by Marek Behun <marek.behun@nic.cz>
+ *
+ * Derived from code in ext4/dev.c, which was based on reiserfs/dev.c
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+
+#include <common.h>
+#include <compiler.h>
+#include <part.h>
+#include <memalign.h>
+
+int fs_devread(struct blk_desc *blk, disk_partition_t *partition,
+	       lbaint_t sector, int byte_offset, int byte_len, char *buf)
+{
+	unsigned block_len;
+	int log2blksz = blk->log2blksz;
+	ALLOC_CACHE_ALIGN_BUFFER(char, sec_buf, (blk ? blk->blksz : 0));
+	if (blk == NULL) {
+		printf("** Invalid Block Device Descriptor (NULL)\n");
+		return 0;
+	}
+
+	/* Check partition boundaries */
+	if ((sector + ((byte_offset + byte_len - 1) >> log2blksz))
+	    >= partition->size) {
+		printf("%s read outside partition " LBAFU "\n", __func__,
+		       sector);
+		return 0;
+	}
+
+	/* Get the read to the beginning of a partition */
+	sector += byte_offset >> log2blksz;
+	byte_offset &= blk->blksz - 1;
+
+	debug(" <" LBAFU ", %d, %d>\n", sector, byte_offset, byte_len);
+
+	if (byte_offset != 0) {
+		int readlen;
+		/* read first part which isn't aligned with start of sector */
+		if (blk_dread(blk, partition->start + sector, 1,
+			      (void *)sec_buf) != 1) {
+			printf(" ** %s read error **\n", __func__);
+			return 0;
+		}
+		readlen = min((int)blk->blksz - byte_offset,
+			      byte_len);
+		memcpy(buf, sec_buf + byte_offset, readlen);
+		buf += readlen;
+		byte_len -= readlen;
+		sector++;
+	}
+
+	if (byte_len == 0)
+		return 1;
+
+	/* read sector aligned part */
+	block_len = byte_len & ~(blk->blksz - 1);
+
+	if (block_len == 0) {
+		ALLOC_CACHE_ALIGN_BUFFER(u8, p, blk->blksz);
+
+		block_len = blk->blksz;
+		blk_dread(blk, partition->start + sector, 1,
+			  (void *)p);
+		memcpy(buf, p, byte_len);
+		return 1;
+	}
+
+	if (blk_dread(blk, partition->start + sector,
+		      block_len >> log2blksz, (void *)buf) !=
+			block_len >> log2blksz) {
+		printf(" ** %s read error - block\n", __func__);
+		return 0;
+	}
+	block_len = byte_len & ~(blk->blksz - 1);
+	buf += block_len;
+	byte_len -= block_len;
+	sector += block_len / blk->blksz;
+
+	if (byte_len != 0) {
+		/* read rest of data which are not in whole sector */
+		if (blk_dread(blk, partition->start + sector, 1,
+			      (void *)sec_buf) != 1) {
+			printf("* %s read error - last part\n", __func__);
+			return 0;
+		}
+		memcpy(buf, sec_buf, byte_len);
+	}
+	return 1;
+}
diff --git a/fs/reiserfs/dev.c b/fs/reiserfs/dev.c
index 5a1ab0a364..7b786e4ed3 100644
--- a/fs/reiserfs/dev.c
+++ b/fs/reiserfs/dev.c
@@ -9,7 +9,7 @@
 #include <common.h>
 #include <config.h>
 #include <reiserfs.h>
-
+#include <fs_internal.h>
 #include "reiserfs_private.h"
 
 static struct blk_desc *reiserfs_blk_desc;
@@ -22,78 +22,8 @@ void reiserfs_set_blk_dev(struct blk_desc *rbdd, disk_partition_t *info)
 	part_info = info;
 }
 
-
-int reiserfs_devread (int sector, int byte_offset, int byte_len, char *buf)
+int reiserfs_devread(int sector, int byte_offset, int byte_len, char *buf)
 {
-	char sec_buf[SECTOR_SIZE];
-	unsigned block_len;
-/*
-	unsigned len = byte_len;
-	u8 *start = buf;
-*/
-	/*
-	*  Check partition boundaries
-	*/
-	if (sector < 0
-	    || ((sector + ((byte_offset + byte_len - 1) >> SECTOR_BITS))
-	    >= part_info->size)) {
-/*		errnum = ERR_OUTSIDE_PART; */
-		printf (" ** reiserfs_devread() read outside partition\n");
-		return 0;
-	}
-
-	/*
-	 *  Get the read to the beginning of a partition.
-	 */
-	sector += byte_offset >> SECTOR_BITS;
-	byte_offset &= SECTOR_SIZE - 1;
-
-#if defined(DEBUG)
-	printf (" <%d, %d, %d> ", sector, byte_offset, byte_len);
-#endif
-
-
-	if (reiserfs_blk_desc == NULL)
-		return 0;
-
-
-	if (byte_offset != 0) {
-		/* read first part which isn't aligned with start of sector */
-		if (reiserfs_blk_desc->block_read(reiserfs_blk_desc,
-						  part_info->start + sector,
-						  1, (void *)sec_buf) != 1) {
-			printf (" ** reiserfs_devread() read error\n");
-			return 0;
-		}
-		memcpy(buf, sec_buf+byte_offset, min(SECTOR_SIZE-byte_offset, byte_len));
-		buf+=min(SECTOR_SIZE-byte_offset, byte_len);
-		byte_len-=min(SECTOR_SIZE-byte_offset, byte_len);
-		sector++;
-	}
-
-	/* read sector aligned part */
-	block_len = byte_len & ~(SECTOR_SIZE-1);
-	if (reiserfs_blk_desc->block_read(reiserfs_blk_desc,
-					  part_info->start + sector,
-					  block_len / SECTOR_SIZE, (void *)buf)
-			!= block_len/SECTOR_SIZE) {
-		printf (" ** reiserfs_devread() read error - block\n");
-		return 0;
-	}
-	buf+=block_len;
-	byte_len-=block_len;
-	sector+= block_len/SECTOR_SIZE;
-
-	if ( byte_len != 0 ) {
-		/* read rest of data which are not in whole sector */
-		if (reiserfs_blk_desc->block_read(reiserfs_blk_desc,
-						  part_info->start + sector,
-						  1, (void *)sec_buf) != 1) {
-			printf (" ** reiserfs_devread() read error - last part\n");
-			return 0;
-		}
-		memcpy(buf, sec_buf, byte_len);
-	}
-
-	return 1;
+	return fs_devread(reiserfs_blk_desc, part_info, sector, byte_offset,
+			  byte_len, buf);
 }
diff --git a/fs/zfs/dev.c b/fs/zfs/dev.c
index 2f409e66cd..7dda42b48b 100644
--- a/fs/zfs/dev.c
+++ b/fs/zfs/dev.c
@@ -11,6 +11,7 @@
 
 #include <common.h>
 #include <config.h>
+#include <fs_internal.h>
 #include <zfs_common.h>
 
 static struct blk_desc *zfs_blk_desc;
@@ -25,87 +26,6 @@ void zfs_set_blk_dev(struct blk_desc *rbdd, disk_partition_t *info)
 /* err */
 int zfs_devread(int sector, int byte_offset, int byte_len, char *buf)
 {
-	short sec_buffer[SECTOR_SIZE/sizeof(short)];
-	char *sec_buf = (char *)sec_buffer;
-	unsigned block_len;
-
-	/*
-	 *	Check partition boundaries
-	 */
-	if ((sector < 0) ||
-		((sector + ((byte_offset + byte_len - 1) >> SECTOR_BITS)) >=
-		 part_info->size)) {
-		/*		errnum = ERR_OUTSIDE_PART; */
-		printf(" ** zfs_devread() read outside partition sector %d\n", sector);
-		return 1;
-	}
-
-	/*
-	 *	Get the read to the beginning of a partition.
-	 */
-	sector += byte_offset >> SECTOR_BITS;
-	byte_offset &= SECTOR_SIZE - 1;
-
-	debug(" <%d, %d, %d>\n", sector, byte_offset, byte_len);
-
-	if (zfs_blk_desc == NULL) {
-		printf("** Invalid Block Device Descriptor (NULL)\n");
-		return 1;
-	}
-
-	if (byte_offset != 0) {
-		/* read first part which isn't aligned with start of sector */
-		if (zfs_blk_desc->block_read(zfs_blk_desc,
-					     part_info->start + sector, 1,
-					     (void *)sec_buf) != 1) {
-			printf(" ** zfs_devread() read error **\n");
-			return 1;
-		}
-		memcpy(buf, sec_buf + byte_offset,
-			   min(SECTOR_SIZE - byte_offset, byte_len));
-		buf += min(SECTOR_SIZE - byte_offset, byte_len);
-		byte_len -= min(SECTOR_SIZE - byte_offset, byte_len);
-		sector++;
-	}
-
-	if (byte_len == 0)
-		return 0;
-
-	/*	read sector aligned part */
-	block_len = byte_len & ~(SECTOR_SIZE - 1);
-
-	if (block_len == 0) {
-		u8 p[SECTOR_SIZE];
-
-		block_len = SECTOR_SIZE;
-		zfs_blk_desc->block_read(zfs_blk_desc,
-					 part_info->start + sector,
-					 1, (void *)p);
-		memcpy(buf, p, byte_len);
-		return 0;
-	}
-
-	if (zfs_blk_desc->block_read(zfs_blk_desc, part_info->start + sector,
-				     block_len / SECTOR_SIZE,
-				     (void *)buf) != block_len / SECTOR_SIZE) {
-		printf(" ** zfs_devread() read error - block\n");
-		return 1;
-	}
-
-	block_len = byte_len & ~(SECTOR_SIZE - 1);
-	buf += block_len;
-	byte_len -= block_len;
-	sector += block_len / SECTOR_SIZE;
-
-	if (byte_len != 0) {
-		/* read rest of data which are not in whole sector */
-		if (zfs_blk_desc->block_read(zfs_blk_desc,
-					     part_info->start + sector,
-					     1, (void *)sec_buf) != 1) {
-			printf(" ** zfs_devread() read error - last part\n");
-			return 1;
-		}
-		memcpy(buf, sec_buf, byte_len);
-	}
-	return 0;
+	return fs_devread(zfs_blk_desc, part_info, sector, byte_offset,
+			  byte_len, buf);
 }