Index: uspace/srv/fs/minixfs/Makefile =================================================================== --- uspace/srv/fs/minixfs/Makefile (revision 0d6ab105d9799eaf1213fea675e7e9fc76e4facb) +++ uspace/srv/fs/minixfs/Makefile (revision 930bacaa57eda20af53925e75553d6d3679e2296) @@ -37,4 +37,5 @@ mfs_ops.c \ mfs_inode.c \ + mfs_read.c \ mfs_utils.c Index: uspace/srv/fs/minixfs/mfs.h =================================================================== --- uspace/srv/fs/minixfs/mfs.h (revision 0d6ab105d9799eaf1213fea675e7e9fc76e4facb) +++ uspace/srv/fs/minixfs/mfs.h (revision 930bacaa57eda20af53925e75553d6d3679e2296) @@ -74,5 +74,5 @@ int dirsize; int block_size; - int fs_version; + mfs_version_t fs_version; uint32_t max_file_size; uint16_t magic; @@ -121,4 +121,6 @@ uint32_t inum); +/*mfs_read.c*/ +int read_map(uint32_t *b, const struct mfs_node *mnode, const uint32_t pos); #endif Index: uspace/srv/fs/minixfs/mfs_read.c =================================================================== --- uspace/srv/fs/minixfs/mfs_read.c (revision 930bacaa57eda20af53925e75553d6d3679e2296) +++ uspace/srv/fs/minixfs/mfs_read.c (revision 930bacaa57eda20af53925e75553d6d3679e2296) @@ -0,0 +1,183 @@ +#include +#include +#include "mfs.h" +#include "mfs_utils.h" + +static int read_map_v1(uint16_t *b, const struct mfs_node *mnode, int rblock); +static int read_map_v2(uint32_t *b, const struct mfs_node *mnode, int rblock); + +/*Given the position in the file expressed in + *bytes, this function returns the on-disk block + *relative to that position. + *Returns zero if the block does not exist. + */ +int read_map(uint32_t *b, const struct mfs_node *mnode, const uint32_t pos) +{ + int r; + + assert(mnode); + assert(mnode->instance); + + const struct mfs_sb_info *sbi = mnode->instance->sbi; + assert(sbi); + + const mfs_version_t fs_version = sbi->fs_version; + const int block_size = sbi->block_size; + + /*Compute relative block number in file*/ + int rblock = pos / block_size; + + if (fs_version == MFS_VERSION_V1) { + if (mnode->ino->i_size < (int32_t) pos) + return -1; + + uint16_t b16 = 0; + r = read_map_v1(&b16, mnode, rblock); + *b = b16; + } else { + if (mnode->ino2->i_size < (int32_t) pos) + return -1; + + r = read_map_v2(b, mnode, rblock); + } + + return r; +} + +static int read_map_v1(uint16_t *b, const struct mfs_node *mnode, int rblock) +{ + const int ptrs_per_block = MFS_BLOCKSIZE / sizeof(uint16_t); + block_t *bi1, *bi2; + const struct mfs_inode *ino = mnode->ino; + int r; + + assert(ino); + assert(mnode->instance); + + if (rblock < V1_NR_DIRECT_ZONES) { + *b = ino->i_dzone[rblock]; + r = EOK; + goto out; + } + + rblock -= V1_NR_DIRECT_ZONES - 1; + + /*Check if the wanted block is in the single indirect zone*/ + if (rblock < ptrs_per_block) { + if (ino->i_izone[0] == 0) { + r = -1; + goto out; + } + + r = read_ind_block(bi1, mnode->instance, ino->i_izone[0]); + + if (r != EOK) + goto out; + + *b = ((uint16_t *) bi1->data)[rblock]; + goto out_block; + } + + rblock -= ptrs_per_block - 1; + + /*The wanted block is in the double indirect zone*/ + uint16_t di_block = rblock / ptrs_per_block; + + /*read the first indirect zone*/ + if (ino->i_izone[1] == 0) { + r = -1; + goto out; + } + + r = read_ind_block(bi1, mnode->instance, ino->i_izone[1]); + + if (r != EOK) + goto out; + + /*read the dobule indirect zone*/ + r = read_ind_block(bi2, mnode->instance, + ((uint16_t *) bi1->data)[di_block]); + + if (r != EOK) + goto out_block; + + *b = ((uint16_t *) bi2->data)[rblock % ptrs_per_block]; + block_put(bi2); + +out_block: + block_put(bi1); +out: + return r; +} + +static int read_map_v2(uint32_t *b, const struct mfs_node *mnode, int rblock) +{ + block_t *bi1, *bi2; + int r; + + assert(mnode); + const struct mfs2_inode *ino2 = mnode->ino2; + + assert(ino2); + assert(mnode->instance); + + const struct mfs_sb_info *sbi = mnode->instance->sbi; + assert(sbi); + + const int ptrs_per_block = sbi->block_size / sizeof(uint32_t); + + if (rblock < V2_NR_DIRECT_ZONES) { + *b = ino2->i_dzone[rblock]; + r = EOK; + goto out; + } + rblock -= V2_NR_DIRECT_ZONES - 1; + + /*Check if the wanted block is in the single indirect zone*/ + if (rblock < ptrs_per_block) { + if (ino2->i_izone[0] == 0) { + r = -1; + goto out; + } + + r = read_ind_block(bi2, mnode->instance, ino2->i_izone[0]); + + if (r != EOK) + goto out; + + *b = ((uint32_t *) bi1->data)[rblock]; + goto out_block; + } + + rblock -= ptrs_per_block - 1; + + /*The wanted block is in the double indirect zone*/ + uint32_t di_block = rblock / ptrs_per_block; + + /*read the first indirect zone*/ + if (ino2->i_izone[1] == 0) { + r = -1; + goto out; + } + + r = read_ind_block(bi1, mnode->instance, ino2->i_izone[1]); + + if (r != EOK) + goto out; + + /*read the second indirect zone*/ + r = read_ind_block(bi2, mnode->instance, + ((uint32_t *) bi1->data)[di_block]); + + if (r != EOK) + goto out_block; + + *b = ((uint32_t *) bi2->data)[rblock % ptrs_per_block]; + block_put(bi2); + +out_block: + block_put(bi1); +out: + return r; +} + Index: uspace/srv/fs/minixfs/mfs_utils.c =================================================================== --- uspace/srv/fs/minixfs/mfs_utils.c (revision 0d6ab105d9799eaf1213fea675e7e9fc76e4facb) +++ uspace/srv/fs/minixfs/mfs_utils.c (revision 930bacaa57eda20af53925e75553d6d3679e2296) @@ -32,4 +32,7 @@ #include +#include +#include +#include "mfs.h" #include "mfs_utils.h" @@ -58,4 +61,39 @@ } +/* + *Read an indirect block from disk and convert its + *content to the native endian format. + */ +int read_ind_block(block_t *b, struct mfs_instance *inst, uint32_t block) +{ + int rc; + unsigned i; + + assert(inst); + devmap_handle_t handle = inst->handle; + struct mfs_sb_info *sbi = inst->sbi; + + assert(sbi); + + rc = block_get(&b, handle, block, BLOCK_FLAGS_NONE); + + if (rc != EOK) + return rc; + + if (sbi->fs_version == MFS_VERSION_V1) { + uint16_t *pt16 = b->data; + + for (i = 0; i < MFS_BLOCKSIZE / sizeof(uint16_t); ++i) + pt16[i] = conv16(sbi->native, pt16[i]); + } else { + uint32_t *pt32 = b->data; + + for (i = 0; i < sbi->block_size / sizeof(uint32_t); ++i) + pt32[i] = conv32(sbi->native, pt32[i]); + } + + return EOK; +} + /** * @} Index: uspace/srv/fs/minixfs/mfs_utils.h =================================================================== --- uspace/srv/fs/minixfs/mfs_utils.h (revision 0d6ab105d9799eaf1213fea675e7e9fc76e4facb) +++ uspace/srv/fs/minixfs/mfs_utils.h (revision 930bacaa57eda20af53925e75553d6d3679e2296) @@ -40,4 +40,5 @@ uint32_t conv32(bool native, uint32_t n); uint64_t conv64(bool native, uint64_t n); +int read_ind_block(block_t *b, struct mfs_instance *inst, uint32_t block); #endif