117 lines
2.6 KiB
C
117 lines
2.6 KiB
C
// See COPYRIGHT for copyright information.
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#ifndef JOS_INC_FS_H
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#define JOS_INC_FS_H
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#include <inc/types.h>
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#include <inc/mmu.h>
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// File nodes (both in-memory and on-disk)
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// Bytes per file system block - same as page size
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#define BLKSIZE PGSIZE
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#define BLKBITSIZE (BLKSIZE * 8)
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// Maximum size of a filename (a single path component), including null
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// Must be a multiple of 4
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#define MAXNAMELEN 128
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// Maximum size of a complete pathname, including null
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#define MAXPATHLEN 1024
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// Number of block pointers in a File descriptor
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#define NDIRECT 10
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// Number of direct block pointers in an indirect block
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#define NINDIRECT (BLKSIZE / 4)
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#define MAXFILESIZE ((NDIRECT + NINDIRECT) * BLKSIZE)
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struct File {
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char f_name[MAXNAMELEN]; // filename
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off_t f_size; // file size in bytes
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uint32_t f_type; // file type
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// Block pointers.
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// A block is allocated iff its value is != 0.
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uint32_t f_direct[NDIRECT]; // direct blocks
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uint32_t f_indirect; // indirect block
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// Pad out to 256 bytes; must do arithmetic in case we're compiling
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// fsformat on a 64-bit machine.
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uint8_t f_pad[256 - MAXNAMELEN - 8 - 4*NDIRECT - 4];
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} __attribute__((packed)); // required only on some 64-bit machines
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// An inode block contains exactly BLKFILES 'struct File's
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#define BLKFILES (BLKSIZE / sizeof(struct File))
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// File types
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#define FTYPE_REG 0 // Regular file
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#define FTYPE_DIR 1 // Directory
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// File system super-block (both in-memory and on-disk)
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#define FS_MAGIC 0x4A0530AE // related vaguely to 'J\0S!'
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struct Super {
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uint32_t s_magic; // Magic number: FS_MAGIC
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uint32_t s_nblocks; // Total number of blocks on disk
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struct File s_root; // Root directory node
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};
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// Definitions for requests from clients to file system
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enum {
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FSREQ_OPEN = 1,
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FSREQ_SET_SIZE,
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// Read returns a Fsret_read on the request page
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FSREQ_READ,
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FSREQ_WRITE,
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// Stat returns a Fsret_stat on the request page
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FSREQ_STAT,
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FSREQ_FLUSH,
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FSREQ_REMOVE,
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FSREQ_SYNC
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};
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union Fsipc {
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struct Fsreq_open {
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char req_path[MAXPATHLEN];
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int req_omode;
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} open;
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struct Fsreq_set_size {
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int req_fileid;
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off_t req_size;
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} set_size;
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struct Fsreq_read {
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int req_fileid;
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size_t req_n;
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} read;
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struct Fsret_read {
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char ret_buf[PGSIZE];
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} readRet;
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struct Fsreq_write {
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int req_fileid;
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size_t req_n;
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char req_buf[PGSIZE - (sizeof(int) + sizeof(size_t))];
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} write;
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struct Fsreq_stat {
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int req_fileid;
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} stat;
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struct Fsret_stat {
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char ret_name[MAXNAMELEN];
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off_t ret_size;
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int ret_isdir;
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} statRet;
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struct Fsreq_flush {
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int req_fileid;
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} flush;
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struct Fsreq_remove {
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char req_path[MAXPATHLEN];
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} remove;
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// Ensure Fsipc is one page
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char _pad[PGSIZE];
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};
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#endif /* !JOS_INC_FS_H */
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