Added support for the basic file operation

Missing seek, but these are the core filesystem operations
provided by this filesystem:
- Read a file
- Append to a file

Additional work is needed around freeing the previous file, so
right now it's limited to appending to existing files, a real
append only filesystem. Unfortunately the overhead of the free
list with multiple open files is becoming tricky.
This commit is contained in:
Christopher Haster
2017-03-19 22:00:56 -05:00
parent 53674cb3bc
commit ed674e8414
3 changed files with 281 additions and 15 deletions

44
lfs.h
View File

@@ -26,12 +26,27 @@ enum lfs_type {
LFS_TYPE_DIR = 2,
};
enum lfs_open_flags {
LFS_O_RDONLY = 0,
LFS_O_WRONLY = 1,
LFS_O_RDWR = 2,
LFS_O_CREAT = 0x0040,
LFS_O_EXCL = 0x0080,
LFS_O_TRUNC = 0x0200,
LFS_O_APPEND = 0x0400,
LFS_O_SYNC = 0x1000,
};
typedef struct lfs_free {
lfs_word_t begin;
lfs_word_t off;
lfs_word_t end;
lfs_disk_struct lfs_disk_free {
lfs_ino_t head;
lfs_word_t ioff;
lfs_word_t icount;
lfs_word_t rev;
lfs_ino_t head;
lfs_word_t off;
lfs_word_t end;
} d;
} lfs_free_t;
@@ -46,7 +61,7 @@ typedef struct lfs_dir {
struct lfs_disk_free free;
} d;
} lfs_dir_t;
} lfs_dir_t;
typedef struct lfs_entry {
lfs_ino_t dir[2];
@@ -65,6 +80,20 @@ typedef struct lfs_entry {
} d;
} lfs_entry_t;
typedef struct lfs_file {
lfs_ino_t head;
lfs_size_t size;
lfs_ino_t wblock;
lfs_word_t windex;
lfs_ino_t rblock;
lfs_word_t rindex;
lfs_off_t roff;
struct lfs_entry entry;
} lfs_file_t;
typedef struct lfs_superblock {
lfs_ino_t pair[2];
lfs_disk_struct lfs_disk_superblock {
@@ -94,5 +123,12 @@ lfs_error_t lfs_mount(lfs_t *lfs);
lfs_error_t lfs_mkdir(lfs_t *lfs, const char *path);
lfs_error_t lfs_file_open(lfs_t *lfs, lfs_file_t *file,
const char *path, int flags);
lfs_error_t lfs_file_close(lfs_t *lfs, lfs_file_t *file);
lfs_ssize_t lfs_file_write(lfs_t *lfs, lfs_file_t *file,
const void *buffer, lfs_size_t size);
lfs_ssize_t lfs_file_read(lfs_t *lfs, lfs_file_t *file,
void *buffer, lfs_size_t size);
#endif