diff options
Diffstat (limited to 'e2fsprogs/ext2fs/bmap.c')
| -rw-r--r-- | e2fsprogs/ext2fs/bmap.c | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/e2fsprogs/ext2fs/bmap.c b/e2fsprogs/ext2fs/bmap.c new file mode 100644 index 0000000..e840044 --- /dev/null +++ b/e2fsprogs/ext2fs/bmap.c @@ -0,0 +1,270 @@ +/* + * bmap.c --- logical to physical block mapping + * + * Copyright (C) 1997 Theodore Ts'o. + * + * %Begin-Header% + * This file may be redistributed under the terms of the GNU Public + * License. + * %End-Header% + */ + +#include <stdio.h> +#include <string.h> +#if HAVE_UNISTD_H +#include <unistd.h> +#endif + +#include "ext2_fs.h" +#include "ext2fs.h" + +#if defined(__GNUC__) && !defined(NO_INLINE_FUNCS) +#define _BMAP_INLINE_ __inline__ +#else +#define _BMAP_INLINE_ +#endif + +extern errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, + struct ext2_inode *inode, + char *block_buf, int bmap_flags, + blk_t block, blk_t *phys_blk); + +#define inode_bmap(inode, nr) ((inode)->i_block[(nr)]) + +static _BMAP_INLINE_ errcode_t block_ind_bmap(ext2_filsys fs, int flags, + blk_t ind, char *block_buf, + int *blocks_alloc, + blk_t nr, blk_t *ret_blk) +{ + errcode_t retval; + blk_t b; + + if (!ind) { + if (flags & BMAP_SET) + return EXT2_ET_SET_BMAP_NO_IND; + *ret_blk = 0; + return 0; + } + retval = io_channel_read_blk(fs->io, ind, 1, block_buf); + 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 + if ((fs->flags & EXT2_FLAG_SWAP_BYTES) || + (fs->flags & EXT2_FLAG_SWAP_BYTES_READ)) + b = ext2fs_swab32(b); +#endif + + if (!b && (flags & BMAP_ALLOC)) { + b = nr ? ((blk_t *) block_buf)[nr-1] : 0; + retval = ext2fs_alloc_block(fs, b, + block_buf + fs->blocksize, &b); + if (retval) + return retval; + +#ifdef EXT2FS_ENABLE_SWAPFS + if ((fs->flags & EXT2_FLAG_SWAP_BYTES) || + (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)) + ((blk_t *) block_buf)[nr] = ext2fs_swab32(b); + else +#endif + ((blk_t *) block_buf)[nr] = b; + + retval = io_channel_write_blk(fs->io, ind, 1, block_buf); + if (retval) + return retval; + + (*blocks_alloc)++; + } + + *ret_blk = b; + return 0; +} + +static _BMAP_INLINE_ errcode_t block_dind_bmap(ext2_filsys fs, int flags, + blk_t dind, char *block_buf, + int *blocks_alloc, + blk_t nr, blk_t *ret_blk) +{ + blk_t b; + errcode_t retval; + blk_t addr_per_block; + + addr_per_block = (blk_t) fs->blocksize >> 2; + + 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, + nr % addr_per_block, ret_blk); + return retval; +} + +static _BMAP_INLINE_ errcode_t block_tind_bmap(ext2_filsys fs, int flags, + blk_t tind, char *block_buf, + int *blocks_alloc, + blk_t nr, blk_t *ret_blk) +{ + blk_t b; + errcode_t retval; + blk_t addr_per_block; + + addr_per_block = (blk_t) fs->blocksize >> 2; + + 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, + nr % addr_per_block, ret_blk); + return retval; +} + +errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode, + char *block_buf, int bmap_flags, blk_t block, + blk_t *phys_blk) +{ + struct ext2_inode inode_buf; + blk_t addr_per_block; + blk_t b; + char *buf = 0; + errcode_t retval = 0; + int blocks_alloc = 0, inode_dirty = 0; + + if (!(bmap_flags & BMAP_SET)) + *phys_blk = 0; + + /* Read inode structure if necessary */ + if (!inode) { + retval = ext2fs_read_inode(fs, ino, &inode_buf); + if (retval) + return retval; + inode = &inode_buf; + } + addr_per_block = (blk_t) fs->blocksize >> 2; + + if (!block_buf) { + retval = ext2fs_get_mem(fs->blocksize * 2, &buf); + if (retval) + return retval; + block_buf = buf; + } + + 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; + + if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) { + retval = ext2fs_alloc_block(fs, b, block_buf, &b); + if (retval) + goto done; + inode_bmap(inode, block) = b; + blocks_alloc++; + *phys_blk = b; + } + goto done; + } + + /* Indirect block */ + block -= EXT2_NDIR_BLOCKS; + if (block < addr_per_block) { + b = inode_bmap(inode, EXT2_IND_BLOCK); + if (!b) { + 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); + if (retval) + goto done; + inode_bmap(inode, EXT2_IND_BLOCK) = b; + blocks_alloc++; + } + retval = block_ind_bmap(fs, bmap_flags, b, block_buf, + &blocks_alloc, block, phys_blk); + goto done; + } + + /* Doubly indirect block */ + block -= addr_per_block; + if (block < addr_per_block * addr_per_block) { + b = inode_bmap(inode, EXT2_DIND_BLOCK); + if (!b) { + 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); + if (retval) + goto done; + inode_bmap(inode, EXT2_DIND_BLOCK) = b; + blocks_alloc++; + } + retval = block_dind_bmap(fs, bmap_flags, b, block_buf, + &blocks_alloc, block, phys_blk); + goto done; + } + + /* Triply indirect block */ + 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_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); + if (retval) + goto done; + inode_bmap(inode, EXT2_TIND_BLOCK) = b; + blocks_alloc++; + } + retval = block_tind_bmap(fs, bmap_flags, b, block_buf, + &blocks_alloc, block, phys_blk); +done: + if (buf) + ext2fs_free_mem(&buf); + if ((retval == 0) && (blocks_alloc || inode_dirty)) { + inode->i_blocks += (blocks_alloc * fs->blocksize) / 512; + retval = ext2fs_write_inode(fs, ino, inode); + } + return retval; +} + + + |