ext2fs.h (BMAP_SET), bmap.c (ext2fs_bmap): Add support for new

	flag, BMAP_SET, which allows the caller to set a
	particular logical->physical block mapping.

4 files changed, 58 insertions, 15 deletions

diff --git a/lib/ext2fs/ChangeLog b/lib/ext2fs/ChangeLog
index 2df731a2..f2ce518d 100644
--- a/lib/ext2fs/ChangeLog
+++ b/lib/ext2fs/ChangeLog
@@ -1,5 +1,11 @@
 2004-12-23  Theodore Ts'o  <tytso@mit.edu>
 
+	* ext2fs.h (BMAP_SET), bmap.c (ext2fs_bmap): Add support for new
+		flag, BMAP_SET, which allows the caller to set a
+		particular logical->physical block mapping.
+
+	* ext2_err.et.in (EXT2_ET_SET_BMAP_NO_IND): New error code
+
 	* initialize.c (calc_reserved_gdt_blocks): #ifdef out all
 		debugging printf statements.
 	
diff --git a/lib/ext2fs/bmap.c b/lib/ext2fs/bmap.c
index 45053dc1..e8400447 100644
--- a/lib/ext2fs/bmap.c
+++ b/lib/ext2fs/bmap.c
@@ -29,8 +29,6 @@ extern errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino,
 			     char *block_buf, int bmap_flags,
 			     blk_t block, blk_t *phys_blk);
 
-#define BMAP_ALLOC	1
-
 #define inode_bmap(inode, nr) ((inode)->i_block[(nr)])
 
 static _BMAP_INLINE_ errcode_t block_ind_bmap(ext2_filsys fs, int flags, 
@@ -42,6 +40,8 @@ static _BMAP_INLINE_ errcode_t block_ind_bmap(ext2_filsys fs, int flags,
 	blk_t		b;
 
 	if (!ind) {
+		if (flags & BMAP_SET)
+			return EXT2_ET_SET_BMAP_NO_IND;
 		*ret_blk = 0;
 		return 0;
 	}
@@ -49,6 +49,17 @@ static _BMAP_INLINE_ errcode_t block_ind_bmap(ext2_filsys fs, int flags,
 	if (retval)
 		return retval;
 
+	if (flags & BMAP_SET) {
+		b = *ret_blk;
+#ifdef EXT2FS_ENABLE_SWAPFS
+		if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
+		    (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
+			b = ext2fs_swab32(b);
+#endif
+		((blk_t *) block_buf)[nr] = b;
+		return io_channel_write_blk(fs->io, ind, 1, block_buf);
+	}
+
 	b = ((blk_t *) block_buf)[nr];
 
 #ifdef EXT2FS_ENABLE_SWAPFS
@@ -94,8 +105,8 @@ static _BMAP_INLINE_ errcode_t block_dind_bmap(ext2_filsys fs, int flags,
 	
 	addr_per_block = (blk_t) fs->blocksize >> 2;
 
-	retval = block_ind_bmap(fs, flags, dind, block_buf, blocks_alloc,
-				nr / addr_per_block, &b);
+	retval = block_ind_bmap(fs, flags & ~BMAP_SET, dind, block_buf, 
+				blocks_alloc, nr / addr_per_block, &b);
 	if (retval)
 		return retval;
 	retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
@@ -114,8 +125,8 @@ static _BMAP_INLINE_ errcode_t block_tind_bmap(ext2_filsys fs, int flags,
 	
 	addr_per_block = (blk_t) fs->blocksize >> 2;
 
-	retval = block_dind_bmap(fs, flags, tind, block_buf, blocks_alloc,
-				 nr / addr_per_block, &b);
+	retval = block_dind_bmap(fs, flags & ~BMAP_SET, tind, block_buf, 
+				 blocks_alloc, nr / addr_per_block, &b);
 	if (retval)
 		return retval;
 	retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
@@ -132,9 +143,10 @@ errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
 	blk_t	b;
 	char	*buf = 0;
 	errcode_t	retval = 0;
-	int		blocks_alloc = 0;
+	int		blocks_alloc = 0, inode_dirty = 0;
 
-	*phys_blk = 0;
+	if (!(bmap_flags & BMAP_SET))
+		*phys_blk = 0;
 
 	/* Read inode structure if necessary */
 	if (!inode) {
@@ -153,6 +165,18 @@ errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
 	}
 
 	if (block < EXT2_NDIR_BLOCKS) {
+		if (bmap_flags & BMAP_SET) {
+			b = *phys_blk;
+#ifdef EXT2FS_ENABLE_SWAPFS
+			if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
+			    (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
+				b = ext2fs_swab32(b);
+#endif
+			inode_bmap(inode, block) = b;
+			inode_dirty++;
+			goto done;
+		}
+
 		*phys_blk = inode_bmap(inode, block);
 		b = block ? inode_bmap(inode, block-1) : 0;
 		
@@ -172,8 +196,11 @@ errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
 	if (block < addr_per_block) {
 		b = inode_bmap(inode, EXT2_IND_BLOCK);
 		if (!b) {
-			if (!(bmap_flags & BMAP_ALLOC))
-			    goto done;
+			if (!(bmap_flags & BMAP_ALLOC)) {
+				if (bmap_flags & BMAP_SET)
+					retval = EXT2_ET_SET_BMAP_NO_IND;
+				goto done;
+			}
 
 			b = inode_bmap(inode, EXT2_IND_BLOCK-1);
  			retval = ext2fs_alloc_block(fs, b, block_buf, &b);
@@ -192,8 +219,11 @@ errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
 	if (block < addr_per_block * addr_per_block) {
 		b = inode_bmap(inode, EXT2_DIND_BLOCK);
 		if (!b) {
-			if (!(bmap_flags & BMAP_ALLOC))
-			    goto done;
+			if (!(bmap_flags & BMAP_ALLOC)) {
+				if (bmap_flags & BMAP_SET)
+					retval = EXT2_ET_SET_BMAP_NO_IND;
+				goto done;
+			}
 
 			b = inode_bmap(inode, EXT2_IND_BLOCK);
  			retval = ext2fs_alloc_block(fs, b, block_buf, &b);
@@ -211,8 +241,11 @@ errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
 	block -= addr_per_block * addr_per_block;
 	b = inode_bmap(inode, EXT2_TIND_BLOCK);
 	if (!b) {
-		if (!(bmap_flags & BMAP_ALLOC))
+		if (!(bmap_flags & BMAP_ALLOC)) {
+			if (bmap_flags & BMAP_SET)
+				retval = EXT2_ET_SET_BMAP_NO_IND;
 			goto done;
+		}
 
 		b = inode_bmap(inode, EXT2_DIND_BLOCK);
 		retval = ext2fs_alloc_block(fs, b, block_buf, &b);
@@ -226,7 +259,7 @@ errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
 done:
 	if (buf)
 		ext2fs_free_mem(&buf);
-	if ((retval == 0) && blocks_alloc) {
+	if ((retval == 0) && (blocks_alloc || inode_dirty)) {
 		inode->i_blocks += (blocks_alloc * fs->blocksize) / 512;
 		retval = ext2fs_write_inode(fs, ino, inode);
 	}
diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in
index 5314c6c5..907b475a 100644
--- a/lib/ext2fs/ext2_err.et.in
+++ b/lib/ext2fs/ext2_err.et.in
@@ -293,5 +293,8 @@ ec	EXT2_ET_RES_GDT_BLOCKS,
 ec	EXT2_ET_RESIZE_INODE_CORRUPT,
 	"Resize inode is corrupt"
 
+ec	EXT2_ET_SET_BMAP_NO_IND,
+	"Missing indirect block not present"
+
 	end
 
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 8d358b49..55bc5473 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -402,7 +402,8 @@ typedef struct ext2_icount *ext2_icount_t;
 /*
  * Flags for ext2fs_bmap
  */
-#define BMAP_ALLOC	1
+#define BMAP_ALLOC	0x0001
+#define BMAP_SET	0x0002
 
 /*
  * Flags for imager.c functions