ufs: untangle ubh_...block...(), part 3

Pass fragment number instead of a block one.  It's available in all
callers and it makes the logics inside those helpers much simpler.
The bitmap they operate upon is with bit per fragment, block being
an aligned group of 1, 2, 4 or 8 adjacent fragments.  We still
need a switch by the number of fragments in block (== number of
bits to check/set/clear), but finding the byte we need to work
with becomes uniform and that makes the things easier to follow.

Signed-off-by: Al Viro <[email protected]>

Author: Al Viro

fs/ufs/balloc.c

@@ -95,7 +95,7 @@ void ufs_free_fragments(struct inode *inode, u64 fragment, unsigned count)
 	 * Trying to reassemble free fragments into block
 	 */
 	blkno = ufs_fragstoblks (bbase);
-	if (ubh_isblockset(uspi, ucpi, blkno)) {
+	if (ubh_isblockset(uspi, ucpi, bbase)) {
 		fs32_sub(sb, &ucg->cg_cs.cs_nffree, uspi->s_fpb);
 		uspi->cs_total.cs_nffree -= uspi->s_fpb;
 		fs32_sub(sb, &UFS_SB(sb)->fs_cs(cgno).cs_nffree, uspi->s_fpb);
@@ -182,10 +182,10 @@ void ufs_free_blocks(struct inode *inode, u64 fragment, unsigned count)
 
 	for (i = bit; i < end_bit; i += uspi->s_fpb) {
 		blkno = ufs_fragstoblks(i);
-		if (ubh_isblockset(uspi, ucpi, blkno)) {
+		if (ubh_isblockset(uspi, ucpi, i)) {
 			ufs_error(sb, "ufs_free_blocks", "freeing free fragment");
 		}
-		ubh_setblock(uspi, ucpi, blkno);
+		ubh_setblock(uspi, ucpi, i);
 		inode_sub_bytes(inode, uspi->s_fpb << uspi->s_fshift);
 		if ((UFS_SB(sb)->s_flags & UFS_CG_MASK) == UFS_CG_44BSD)
 			ufs_clusteracct (sb, ucpi, blkno, 1);
@@ -716,7 +716,7 @@ static u64 ufs_alloccg_block(struct inode *inode,
 	/*
 	 * If the requested block is available, use it.
 	 */
-	if (ubh_isblockset(uspi, ucpi, ufs_fragstoblks(goal))) {
+	if (ubh_isblockset(uspi, ucpi, goal)) {
 		result = goal;
 		goto gotit;
 	}
@@ -730,7 +730,7 @@ static u64 ufs_alloccg_block(struct inode *inode,
 	if (!try_add_frags(inode, uspi->s_fpb))
 		return 0;
 	blkno = ufs_fragstoblks(result);
-	ubh_clrblock(uspi, ucpi, blkno);
+	ubh_clrblock(uspi, ucpi, result);
 	if ((UFS_SB(sb)->s_flags & UFS_CG_MASK) == UFS_CG_44BSD)
 		ufs_clusteracct (sb, ucpi, blkno, -1);
 

fs/ufs/util.h

@@ -456,65 +456,68 @@ static inline unsigned _ubh_find_last_zero_bit_(
 } 	
 
 static inline int ubh_isblockset(struct ufs_sb_private_info *uspi,
-	struct ufs_cg_private_info *ucpi, unsigned block)
+	struct ufs_cg_private_info *ucpi, unsigned int frag)
 {
 	struct ufs_buffer_head *ubh = UCPI_UBH(ucpi);
-	unsigned begin = ucpi->c_freeoff;
+	u8 *p = ubh_get_addr(ubh, ucpi->c_freeoff + (frag >> 3));
 	u8 mask;
+
 	switch (uspi->s_fpb) {
 	case 8:
-	    	return (*ubh_get_addr (ubh, begin + block) == 0xff);
+		return *p == 0xff;
 	case 4:
-		mask = 0x0f << ((block & 0x01) << 2);
-		return (*ubh_get_addr (ubh, begin + (block >> 1)) & mask) == mask;
+		mask = 0x0f << (frag & 4);
+		return (*p & mask) == mask;
 	case 2:
-		mask = 0x03 << ((block & 0x03) << 1);
-		return (*ubh_get_addr (ubh, begin + (block >> 2)) & mask) == mask;
+		mask = 0x03 << (frag & 6);
+		return (*p & mask) == mask;
 	case 1:
-		mask = 0x01 << (block & 0x07);
-		return (*ubh_get_addr (ubh, begin + (block >> 3)) & mask) == mask;
+		mask = 0x01 << (frag & 7);
+		return (*p & mask) == mask;
 	}
 	return 0;	
 }
 
 static inline void ubh_clrblock(struct ufs_sb_private_info *uspi,
-	struct ufs_cg_private_info *ucpi, unsigned block)
+	struct ufs_cg_private_info *ucpi, unsigned int frag)
 {
 	struct ufs_buffer_head *ubh = UCPI_UBH(ucpi);
-	unsigned begin = ucpi->c_freeoff;
+	u8 *p = ubh_get_addr(ubh, ucpi->c_freeoff + (frag >> 3));
+
 	switch (uspi->s_fpb) {
 	case 8:
-	    	*ubh_get_addr (ubh, begin + block) = 0x00;
+		*p = 0x00;
 	    	return; 
 	case 4:
-		*ubh_get_addr (ubh, begin + (block >> 1)) &= ~(0x0f << ((block & 0x01) << 2));
+		*p &= ~(0x0f << (frag & 4));
 		return;
 	case 2:
-		*ubh_get_addr (ubh, begin + (block >> 2)) &= ~(0x03 << ((block & 0x03) << 1));
+		*p &= ~(0x03 << (frag & 6));
 		return;
 	case 1:
-		*ubh_get_addr (ubh, begin + (block >> 3)) &= ~(0x01 << ((block & 0x07)));
+		*p &= ~(0x01 << (frag & 7));
 		return;
 	}
 }
 
 static inline void ubh_setblock(struct ufs_sb_private_info * uspi,
-	struct ufs_cg_private_info *ucpi, unsigned block)
+	struct ufs_cg_private_info *ucpi, unsigned int frag)
 {
 	struct ufs_buffer_head *ubh = UCPI_UBH(ucpi);
-	unsigned begin = ucpi->c_freeoff;
+	u8 *p = ubh_get_addr(ubh, ucpi->c_freeoff + (frag >> 3));
+
 	switch (uspi->s_fpb) {
 	case 8:
-	    	*ubh_get_addr(ubh, begin + block) = 0xff;
+		*p = 0xff;
 	    	return;
 	case 4:
-		*ubh_get_addr(ubh, begin + (block >> 1)) |= (0x0f << ((block & 0x01) << 2));
+		*p |= 0x0f << (frag & 4);
 		return;
 	case 2:
-		*ubh_get_addr(ubh, begin + (block >> 2)) |= (0x03 << ((block & 0x03) << 1));
+		*p |= 0x03 << (frag & 6);
 		return;
 	case 1:
-		*ubh_get_addr(ubh, begin + (block >> 3)) |= (0x01 << ((block & 0x07)));
+		*p |= 0x01 << (frag & 7);
 		return;
 	}
 }