add open and close functions, clean up ref_count=0 inodes and blocks
This commit is contained in:
parent
447a1448ad
commit
ef7f9ff553
2
config.h
2
config.h
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@ -1,6 +1,7 @@
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#ifndef CONFIG_FILE
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#define CONFIG_FILE
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/* Global config options */
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#define DEBUG 1
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#define LOG_LEVEL 4
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@ -23,6 +24,7 @@
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#define FS_BLOCK_SIZE 4096
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#define FS_MAX_BITMAP_SIZE 64
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#define FS_MAX_PATH_LEN 512
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#define FS_MAX_OPEN_FD 32
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#endif
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7
inc/fs.h
7
inc/fs.h
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@ -41,6 +41,11 @@ struct fs_directory_record {
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unsigned int inode_no;
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};
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struct fs_file_description {
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unsigned int inode;
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unsigned int rw_offset;
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};
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char *fs_get_cwd(void);
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int fs_create(void *d);
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@ -50,5 +55,7 @@ int fs_mkfs(void *d);
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int fs_ls(void *d);
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int fs_la(void *d);
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int fs_rm(void *d);
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int fs_open(void *d);
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int fs_close(void *d);
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int fs_allow_write(void *d);
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int fs_prohibit_write(void *d);
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@ -15,9 +15,16 @@ static const struct CliCommandEntry cmd[] = {
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// mandatory commands
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{"mkfs", 1, (enum CliArgType[]) {INT}, fs_mkfs},
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{"create", 1, (enum CliArgType[]) {STR}, fs_create},
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//{"stat", 1, (enum CliArgType[]) {STR}, fs_stat},
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{"ls", 0, NULL, fs_ls},
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{"ln", 2, (enum CliArgType[]) {STR, STR}, fs_ln},
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{"rm", 1, (enum CliArgType[]) {STR}, fs_rm},
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//{"truncate", 2, (enum CliArgType[]) {STR, INT}, fs_truncate},
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{"open", 1, (enum CliArgType[]) {STR}, fs_open},
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//{"seek", 2, (enum CliArgType[]) {INT, INT}, fs_seek},
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//{"read", 2, (enum CliArgType[]) {INT, INT}, fs_read},
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//{"write", 2, (enum CliArgType[]) {INT, STR}, fs_write},
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{"close", 1, (enum CliArgType[]) {INT}, fs_close},
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// custom commands
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{"use", 1, (enum CliArgType[]) {STR}, fs_use},
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172
src/fs.c
172
src/fs.c
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@ -21,6 +21,8 @@ static int write_permitted;
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static char fs_cwd[FS_MAX_PATH_LEN+1];
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static unsigned int fs_cwd_inode_ptr;
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static struct fs_file_description fs_file_descriptions[FS_MAX_OPEN_FD];
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static int read_block(unsigned int block_no, void *data)
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{
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@ -384,9 +386,10 @@ static int *find_filename_in_directory(unsigned int dir_inode_ptr, char *fname)
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continue;
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// filename found
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int *r = malloc(sizeof(int) * 2);
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int *r = malloc(sizeof(int) * 3);
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r[0] = i;
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r[1] = k;
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r[2] = recs[k].inode_no;
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return r;
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}
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}
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@ -477,35 +480,77 @@ static int fs_remove_fname_from_directory(unsigned int dir_inode_ptr, char *fnam
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for (int i = 0; i < BLOCK_ADDRESSES_PER_INODE; i++) {
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struct fs_directory_record recs[DIRECTORY_RECORDS_PER_BLOCK];
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if (dir.blocks[i]) {
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read_block(dir.blocks[i], (void *) &recs);
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if (!dir.blocks[i])
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continue;
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for (int k = 0; k < DIRECTORY_RECORDS_PER_BLOCK; k++) {
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if (!recs[k].inode_no)
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continue;
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read_block(dir.blocks[i], (void *) &recs);
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if (!strcmp(fname, recs[k].fname)) {
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pr("Directory record for '%s' found in block=%d, record=%d, removing\n", fname, i, k);
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for (int k = 0; k < DIRECTORY_RECORDS_PER_BLOCK; k++) {
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if (!recs[k].inode_no)
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continue;
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if (strcmp(fname, recs[k].fname))
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continue;
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pr("Directory record for '%s' found in block=%d, record=%d, removing\n", fname, i, k);
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unsigned int inode_location_cache = read_inode_ptr(recs[k].inode_no);
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// decrement ref_count
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struct fs_inode f;
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read_block(read_inode_ptr(recs[k].inode_no), (void *) &f);
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f.ref_count--;
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write_block(read_inode_ptr(recs[k].inode_no), (void *) &f);
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// if it drops to zero, nullify inode_ptr pointing to this inode
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if (!f.ref_count) {
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pr("ref_count=0, clearing inode_ptr\n");
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write_inode_ptr(recs[k].inode_no, 0);
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// if no fd reference this inode, clean it up altogether
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int i;
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for (i = 0; i < FS_MAX_OPEN_FD; i++)
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if (fs_file_descriptions[i].inode == inode_location_cache)
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break;
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if (i == FS_MAX_OPEN_FD) {
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pr("No open fd reference inode %d, cleaning up\n", inode_location_cache);
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// decrement ref_count
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struct fs_inode f;
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read_block(read_inode_ptr(recs[k].inode_no), (void *) &f);
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f.ref_count--;
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write_block(read_inode_ptr(recs[k].inode_no), (void *) &f);
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read_block(inode_location_cache, (void *) &f);
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// if it drops to zero, nullify inode_ptr pointing to this inode
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if (!f.ref_count) {
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pr("ref_count=0, clearing inode_ptr\n");
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write_inode_ptr(recs[k].inode_no, 0);
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// clear blocks referenced in base inode
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for (int i = 0; i < BLOCK_ADDRESSES_PER_INODE; i++) {
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if (f.blocks[i])
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mark_free(f.blocks[i]);
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}
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mark_free(inode_location_cache);
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// clear directory record inode_ptr
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recs[k].inode_no = 0;
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write_block(dir.blocks[i], (void *) &recs);
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// clear blocks referenced in inode extensions
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struct fs_inode_extension ext;
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unsigned int next_extension = f.next_extension;
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goto fs_remove_fname_from_directory_finish;
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while (next_extension) {
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mark_free(next_extension);
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read_block(next_extension, (void *) &ext);
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next_extension = ext.next_extension;
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for (int i = 0; i < BLOCK_ADDRESSES_PER_INODE_EXTENSION; i++) {
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if (ext.blocks[i])
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mark_free(ext.blocks[i]);
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}
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}
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} else {
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pr("Inode %d is still referenced by fd %d, not removing it\n",
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inode_location_cache, i);
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}
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}
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// clear directory record inode_ptr
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recs[k].inode_no = 0;
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write_block(dir.blocks[i], (void *) &recs);
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goto fs_remove_fname_from_directory_finish;
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}
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}
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@ -520,6 +565,93 @@ fs_remove_fname_from_directory_finish:
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return 0;
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}
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int fs_open(void *d)
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{
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char *fname = *((char **) d);
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// find file inode
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struct fs_file_description fd;
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{
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int *r = find_filename_in_directory(fs_cwd_inode_ptr, fname);
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if (!r) {
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pr_err("no such file: '%s'\n", fname);
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return 0;
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}
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fd.inode = read_inode_ptr(r[2]);
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free(r);
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}
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fd.rw_offset = 0;
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// find free file descriptor
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int free_fd;
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for (free_fd = 0; (free_fd < FS_MAX_OPEN_FD) && (fs_file_descriptions[free_fd].inode); free_fd++);
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if (free_fd == FS_MAX_OPEN_FD) {
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pr_err("no free file descriptor found\n");
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return 0;
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}
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memcpy(&(fs_file_descriptions[free_fd]), &fd, sizeof(struct fs_file_description));
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pr_stdout("%d\n", free_fd);
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return 0;
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}
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int fs_close(void *d)
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{
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int fd = *((int *) d);
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// remove inode number from fd
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if (!fs_file_descriptions[fd].inode) {
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pr_err("fd %d is not open\n", fd);
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return 0;
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}
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unsigned int inode_location_cache = fs_file_descriptions[fd].inode;
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fs_file_descriptions[fd].inode = 0;
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pr("fd %d closed\n", fd);
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// cleanup file data on disk if ref_count=0
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// and no other open descriptor references it's inode
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struct fs_inode f;
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read_block(inode_location_cache, (void *) &f);
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if (f.ref_count)
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return 0;
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for (int i = 0; i < FS_MAX_OPEN_FD; i++)
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if (fs_file_descriptions[i].inode == inode_location_cache)
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return 0;
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// if ended up here, the inode is not referenced anywhere
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pr("No open fd reference inode %d, cleaning up\n", inode_location_cache);
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// clear blocks referenced in base inode
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for (int i = 0; i < BLOCK_ADDRESSES_PER_INODE; i++) {
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if (f.blocks[i])
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mark_free(f.blocks[i]);
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}
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mark_free(inode_location_cache);
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// clear blocks referenced in inode extensions
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struct fs_inode_extension ext;
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unsigned int next_extension = f.next_extension;
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while (next_extension) {
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mark_free(next_extension);
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read_block(next_extension, (void *) &ext);
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next_extension = ext.next_extension;
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for (int i = 0; i < BLOCK_ADDRESSES_PER_INODE_EXTENSION; i++) {
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if (ext.blocks[i])
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mark_free(ext.blocks[i]);
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}
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}
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}
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int fs_create(void *d)
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{
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if (!write_permitted) {
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