456359aa72
Change-Id: Ib6b81403f877c363a286c654e0524fa1cb781b80
759 lines
24 KiB
C
759 lines
24 KiB
C
/* Created (MFS based):
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* February 2010 (Evgeniy Ivanov)
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*/
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#include "fs.h"
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#include <stddef.h>
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#include <string.h>
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#include <stdlib.h>
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#include <minix/com.h>
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#include <minix/u64.h>
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#include "buf.h"
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#include "inode.h"
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#include "super.h"
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#include <minix/vfsif.h>
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#include <sys/param.h>
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#include <assert.h>
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#include <sys/param.h>
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static struct buf *rahead(struct inode *rip, block_t baseblock, u64_t
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position, unsigned bytes_ahead);
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static int rw_chunk(struct inode *rip, u64_t position, unsigned off,
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size_t chunk, unsigned left, int rw_flag, cp_grant_id_t gid, unsigned
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buf_off, unsigned int block_size, int *completed);
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static off_t rdahedpos; /* position to read ahead */
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static struct inode *rdahed_inode; /* pointer to inode to read ahead */
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/*===========================================================================*
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* fs_readwrite *
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*===========================================================================*/
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int fs_readwrite(void)
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{
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int r, rw_flag, block_spec;
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int regular;
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cp_grant_id_t gid;
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off_t position, f_size, bytes_left;
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unsigned int off, cum_io, block_size, chunk;
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mode_t mode_word;
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int completed;
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struct inode *rip;
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size_t nrbytes;
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r = OK;
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/* Find the inode referred */
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if ((rip = find_inode(fs_dev, (ino_t) fs_m_in.REQ_INODE_NR)) == NULL)
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return(EINVAL);
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mode_word = rip->i_mode & I_TYPE;
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regular = (mode_word == I_REGULAR || mode_word == I_NAMED_PIPE);
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block_spec = (mode_word == I_BLOCK_SPECIAL ? 1 : 0);
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/* Determine blocksize */
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if (block_spec) {
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block_size = get_block_size( (dev_t) rip->i_block[0]);
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f_size = MAX_FILE_POS;
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} else {
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block_size = rip->i_sp->s_block_size;
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f_size = rip->i_size;
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if (f_size < 0) f_size = MAX_FILE_POS;
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}
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rw_flag = (fs_m_in.m_type == REQ_READ ? READING : WRITING);
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switch(fs_m_in.m_type) {
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case REQ_READ: rw_flag = READING; break;
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case REQ_WRITE: rw_flag = WRITING; break;
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case REQ_PEEK: rw_flag = PEEKING; break;
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default: panic("odd request");
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}
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gid = (cp_grant_id_t) fs_m_in.REQ_GRANT;
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position = (off_t) fs_m_in.REQ_SEEK_POS_LO;
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nrbytes = (size_t) fs_m_in.REQ_NBYTES;
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rdwt_err = OK; /* set to EIO if disk error occurs */
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if (rw_flag == WRITING && !block_spec) {
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/* Check in advance to see if file will grow too big. */
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if (position > (off_t) (rip->i_sp->s_max_size - nrbytes))
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return(EFBIG);
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}
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cum_io = 0;
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/* Split the transfer into chunks that don't span two blocks. */
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while (nrbytes != 0) {
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off = (unsigned int) (position % block_size);/* offset in blk*/
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chunk = MIN(nrbytes, block_size - off);
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if (rw_flag == READING) {
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bytes_left = f_size - position;
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if (position >= f_size) break; /* we are beyond EOF */
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if (chunk > bytes_left) chunk = (int) bytes_left;
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}
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/* Read or write 'chunk' bytes. */
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r = rw_chunk(rip, ((u64_t)((unsigned long)position)), off, chunk,
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nrbytes, rw_flag, gid, cum_io, block_size, &completed);
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if (r != OK) break; /* EOF reached */
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if (rdwt_err < 0) break;
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/* Update counters and pointers. */
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nrbytes -= chunk; /* bytes yet to be read */
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cum_io += chunk; /* bytes read so far */
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position += (off_t) chunk; /* position within the file */
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}
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fs_m_out.RES_SEEK_POS_LO = position; /* It might change later and the VFS
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has to know this value */
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/* On write, update file size and access time. */
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if (rw_flag == WRITING) {
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if (regular || mode_word == I_DIRECTORY) {
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if (position > f_size) rip->i_size = position;
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}
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}
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/* Check to see if read-ahead is called for, and if so, set it up. */
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if(rw_flag == READING && rip->i_seek == NO_SEEK &&
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(unsigned int) position % block_size == 0 &&
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(regular || mode_word == I_DIRECTORY)) {
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rdahed_inode = rip;
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rdahedpos = position;
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}
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rip->i_seek = NO_SEEK;
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if (rdwt_err != OK) r = rdwt_err; /* check for disk error */
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if (rdwt_err == END_OF_FILE) r = OK;
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if (r == OK) {
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if (rw_flag == READING) rip->i_update |= ATIME;
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if (rw_flag == WRITING) rip->i_update |= CTIME | MTIME;
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rip->i_dirt = IN_DIRTY; /* inode is thus now dirty */
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}
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fs_m_out.RES_NBYTES = cum_io;
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return(r);
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}
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/*===========================================================================*
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* fs_breadwrite *
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*===========================================================================*/
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int fs_breadwrite(void)
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{
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int r, rw_flag, completed;
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cp_grant_id_t gid;
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u64_t position;
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unsigned int off, cum_io, chunk, block_size;
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size_t nrbytes;
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/* Pseudo inode for rw_chunk */
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struct inode rip;
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r = OK;
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/* Get the values from the request message */
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rw_flag = (fs_m_in.m_type == REQ_BREAD ? READING : WRITING);
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gid = (cp_grant_id_t) fs_m_in.REQ_GRANT;
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position = make64((unsigned long) fs_m_in.REQ_SEEK_POS_LO,
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(unsigned long) fs_m_in.REQ_SEEK_POS_HI);
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nrbytes = (size_t) fs_m_in.REQ_NBYTES;
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block_size = get_block_size( (dev_t) fs_m_in.REQ_DEV2);
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rip.i_block[0] = (block_t) fs_m_in.REQ_DEV2;
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rip.i_mode = I_BLOCK_SPECIAL;
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rip.i_size = 0;
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rdwt_err = OK; /* set to EIO if disk error occurs */
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cum_io = 0;
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/* Split the transfer into chunks that don't span two blocks. */
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while (nrbytes > 0) {
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off = rem64u(position, block_size); /* offset in blk*/
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chunk = min(nrbytes, block_size - off);
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/* Read or write 'chunk' bytes. */
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r = rw_chunk(&rip, position, off, chunk, nrbytes, rw_flag, gid,
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cum_io, block_size, &completed);
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if (r != OK) break; /* EOF reached */
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if (rdwt_err < 0) break;
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/* Update counters and pointers. */
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nrbytes -= chunk; /* bytes yet to be read */
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cum_io += chunk; /* bytes read so far */
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position = add64ul(position, chunk); /* position within the file */
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}
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fs_m_out.RES_SEEK_POS_LO = ex64lo(position);
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fs_m_out.RES_SEEK_POS_HI = ex64hi(position);
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if (rdwt_err != OK) r = rdwt_err; /* check for disk error */
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if (rdwt_err == END_OF_FILE) r = OK;
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fs_m_out.RES_NBYTES = cum_io;
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return(r);
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}
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/*===========================================================================*
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* rw_chunk *
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*===========================================================================*/
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static int rw_chunk(rip, position, off, chunk, left, rw_flag, gid,
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buf_off, block_size, completed)
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register struct inode *rip; /* pointer to inode for file to be rd/wr */
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u64_t position; /* position within file to read or write */
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unsigned off; /* off within the current block */
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unsigned int chunk; /* number of bytes to read or write */
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unsigned left; /* max number of bytes wanted after position */
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int rw_flag; /* READING, WRITING or PEEKING */
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cp_grant_id_t gid; /* grant */
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unsigned buf_off; /* offset in grant */
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unsigned int block_size; /* block size of FS operating on */
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int *completed; /* number of bytes copied */
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{
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/* Read or write (part of) a block. */
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register struct buf *bp = NULL;
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register int r = OK;
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int n, block_spec;
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block_t b;
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dev_t dev;
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ino_t ino = VMC_NO_INODE;
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u64_t ino_off = rounddown(position, block_size);
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/* rw_flag:
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* READING: read from FS, copy to user
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* WRITING: copy from user, write to FS
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* PEEKING: try to get all the blocks into the cache, no copying
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*/
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*completed = 0;
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block_spec = (rip->i_mode & I_TYPE) == I_BLOCK_SPECIAL;
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if (block_spec) {
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b = div64u(position, block_size);
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dev = (dev_t) rip->i_block[0];
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} else {
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if (ex64hi(position) != 0)
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panic("rw_chunk: position too high");
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b = read_map(rip, (off_t) ex64lo(position), 0);
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dev = rip->i_dev;
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ino = rip->i_num;
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assert(ino != VMC_NO_INODE);
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}
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if (!block_spec && b == NO_BLOCK) {
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if (rw_flag == READING) {
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/* Reading from a nonexistent block. Must read as all zeros.*/
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r = sys_safememset(VFS_PROC_NR, gid, (vir_bytes) buf_off,
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0, (size_t) chunk);
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if(r != OK) {
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printf("ext2fs: sys_safememset failed\n");
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}
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return r;
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} else {
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/* Writing to or peeking a nonexistent block.
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* Create and enter in inode.
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*/
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if ((bp = new_block(rip, (off_t) ex64lo(position))) == NULL)
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return(err_code);
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}
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} else if (rw_flag == READING || rw_flag == PEEKING) {
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/* Read and read ahead if convenient. */
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bp = rahead(rip, b, position, left);
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} else {
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/* Normally an existing block to be partially overwritten is first read
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* in. However, a full block need not be read in. If it is already in
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* the cache, acquire it, otherwise just acquire a free buffer.
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*/
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n = (chunk == block_size ? NO_READ : NORMAL);
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if (!block_spec && off == 0 && (off_t) ex64lo(position) >= rip->i_size)
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n = NO_READ;
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if(block_spec) {
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assert(ino == VMC_NO_INODE);
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bp = get_block(dev, b, n);
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} else {
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assert(ino != VMC_NO_INODE);
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assert(!(ino_off % block_size));
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bp = lmfs_get_block_ino(dev, b, n, ino, ino_off);
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}
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}
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/* In all cases, bp now points to a valid buffer. */
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if (bp == NULL)
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panic("bp not valid in rw_chunk, this can't happen");
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if (rw_flag == WRITING && chunk != block_size && !block_spec &&
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(off_t) ex64lo(position) >= rip->i_size && off == 0) {
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zero_block(bp);
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}
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if (rw_flag == READING) {
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/* Copy a chunk from the block buffer to user space. */
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r = sys_safecopyto(VFS_PROC_NR, gid, (vir_bytes) buf_off,
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(vir_bytes) (b_data(bp)+off), (size_t) chunk);
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} else if(rw_flag == WRITING) {
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/* Copy a chunk from user space to the block buffer. */
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r = sys_safecopyfrom(VFS_PROC_NR, gid, (vir_bytes) buf_off,
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(vir_bytes) (b_data(bp)+off), (size_t) chunk);
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lmfs_markdirty(bp);
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}
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n = (off + chunk == block_size ? FULL_DATA_BLOCK : PARTIAL_DATA_BLOCK);
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put_block(bp, n);
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return(r);
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}
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/*===========================================================================*
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* read_map *
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*===========================================================================*/
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block_t read_map(rip, position, opportunistic)
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register struct inode *rip; /* ptr to inode to map from */
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off_t position; /* position in file whose blk wanted */
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int opportunistic;
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{
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/* Given an inode and a position within the corresponding file, locate the
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* block number in which that position is to be found and return it.
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*/
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struct buf *bp;
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int index;
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block_t b;
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unsigned long excess, block_pos;
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static char first_time = TRUE;
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static long addr_in_block;
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static long addr_in_block2;
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static long doub_ind_s;
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static long triple_ind_s;
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static long out_range_s;
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int iomode = NORMAL;
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if(opportunistic) iomode = PREFETCH;
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if (first_time) {
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addr_in_block = rip->i_sp->s_block_size / BLOCK_ADDRESS_BYTES;
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addr_in_block2 = addr_in_block * addr_in_block;
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doub_ind_s = EXT2_NDIR_BLOCKS + addr_in_block;
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triple_ind_s = doub_ind_s + addr_in_block2;
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out_range_s = triple_ind_s + addr_in_block2 * addr_in_block;
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first_time = FALSE;
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}
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block_pos = position / rip->i_sp->s_block_size; /* relative blk # in file */
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/* Is 'position' to be found in the inode itself? */
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if (block_pos < EXT2_NDIR_BLOCKS)
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return(rip->i_block[block_pos]);
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/* It is not in the inode, so it must be single, double or triple indirect */
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if (block_pos < doub_ind_s) {
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b = rip->i_block[EXT2_NDIR_BLOCKS]; /* address of single indirect block */
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index = block_pos - EXT2_NDIR_BLOCKS;
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} else if (block_pos >= out_range_s) { /* TODO: do we need it? */
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return(NO_BLOCK);
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} else {
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/* double or triple indirect block. At first if it's triple,
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* find double indirect block.
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*/
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excess = block_pos - doub_ind_s;
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b = rip->i_block[EXT2_DIND_BLOCK];
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if (block_pos >= triple_ind_s) {
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b = rip->i_block[EXT2_TIND_BLOCK];
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if (b == NO_BLOCK) return(NO_BLOCK);
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bp = get_block(rip->i_dev, b, NORMAL); /* get triple ind block */
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ASSERT(lmfs_dev(bp) != NO_DEV);
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ASSERT(lmfs_dev(bp) == rip->i_dev);
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excess = block_pos - triple_ind_s;
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index = excess / addr_in_block2;
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b = rd_indir(bp, index); /* num of double ind block */
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put_block(bp, INDIRECT_BLOCK); /* release triple ind block */
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excess = excess % addr_in_block2;
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}
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if (b == NO_BLOCK) return(NO_BLOCK);
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bp = get_block(rip->i_dev, b, iomode); /* get double indirect block */
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if(opportunistic && lmfs_dev(bp) == NO_DEV) {
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put_block(bp, INDIRECT_BLOCK);
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return NO_BLOCK;
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}
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ASSERT(lmfs_dev(bp) != NO_DEV);
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ASSERT(lmfs_dev(bp) == rip->i_dev);
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index = excess / addr_in_block;
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b = rd_indir(bp, index); /* num of single ind block */
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put_block(bp, INDIRECT_BLOCK); /* release double ind block */
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index = excess % addr_in_block; /* index into single ind blk */
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}
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if (b == NO_BLOCK) return(NO_BLOCK);
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bp = get_block(rip->i_dev, b, iomode); /* get single indirect block */
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if(opportunistic && lmfs_dev(bp) == NO_DEV) {
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put_block(bp, INDIRECT_BLOCK);
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return NO_BLOCK;
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}
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ASSERT(lmfs_dev(bp) != NO_DEV);
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ASSERT(lmfs_dev(bp) == rip->i_dev);
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b = rd_indir(bp, index);
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put_block(bp, INDIRECT_BLOCK); /* release single ind block */
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return(b);
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}
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struct buf *get_block_map(register struct inode *rip, u64_t position)
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{
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block_t b = read_map(rip, position, 0); /* get block number */
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int block_size = get_block_size(rip->i_dev);
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if(b == NO_BLOCK)
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return NULL;
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position = rounddown(position, block_size);
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assert(rip->i_num != VMC_NO_INODE);
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return lmfs_get_block_ino(rip->i_dev, b, NORMAL, rip->i_num, position);
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}
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/*===========================================================================*
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* rd_indir *
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*===========================================================================*/
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block_t rd_indir(bp, index)
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struct buf *bp; /* pointer to indirect block */
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int index; /* index into *bp */
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{
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if (bp == NULL)
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panic("rd_indir() on NULL");
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/* TODO: use conv call */
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return conv4(le_CPU, b_ind(bp)[index]);
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}
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/*===========================================================================*
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* read_ahead *
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*===========================================================================*/
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void read_ahead()
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{
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/* Read a block into the cache before it is needed. */
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unsigned int block_size;
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register struct inode *rip;
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struct buf *bp;
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block_t b;
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if(!rdahed_inode)
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return;
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rip = rdahed_inode; /* pointer to inode to read ahead from */
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block_size = get_block_size(rip->i_dev);
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rdahed_inode = NULL; /* turn off read ahead */
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if ( (b = read_map(rip, rdahedpos, 1)) == NO_BLOCK) return; /* at EOF */
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assert(rdahedpos >= 0); /* So we can safely cast it to unsigned below */
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bp = rahead(rip, b, ((u64_t)((unsigned long)rdahedpos)), block_size);
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put_block(bp, PARTIAL_DATA_BLOCK);
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}
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/*===========================================================================*
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* rahead *
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*===========================================================================*/
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static struct buf *rahead(rip, baseblock, position, bytes_ahead)
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register struct inode *rip; /* pointer to inode for file to be read */
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block_t baseblock; /* block at current position */
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u64_t position; /* position within file */
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unsigned bytes_ahead; /* bytes beyond position for immediate use */
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{
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/* Fetch a block from the cache or the device. If a physical read is
|
|
* required, prefetch as many more blocks as convenient into the cache.
|
|
* This usually covers bytes_ahead and is at least BLOCKS_MINIMUM.
|
|
* The device driver may decide it knows better and stop reading at a
|
|
* cylinder boundary (or after an error). Rw_scattered() puts an optional
|
|
* flag on all reads to allow this.
|
|
*/
|
|
/* Minimum number of blocks to prefetch. */
|
|
# define BLOCKS_MINIMUM (nr_bufs < 50 ? 18 : 32)
|
|
int nr_bufs = lmfs_nr_bufs();
|
|
int block_spec, read_q_size;
|
|
unsigned int blocks_ahead, fragment, block_size;
|
|
block_t block, blocks_left;
|
|
off_t ind1_pos;
|
|
dev_t dev;
|
|
struct buf *bp = NULL;
|
|
static unsigned int readqsize = 0;
|
|
static struct buf **read_q = NULL;
|
|
u64_t position_running;
|
|
|
|
if(readqsize != nr_bufs) {
|
|
if(readqsize > 0) {
|
|
assert(read_q != NULL);
|
|
free(read_q);
|
|
read_q = NULL;
|
|
readqsize = 0;
|
|
}
|
|
|
|
assert(readqsize == 0);
|
|
assert(read_q == NULL);
|
|
|
|
if(!(read_q = malloc(sizeof(read_q[0])*nr_bufs)))
|
|
panic("couldn't allocate read_q");
|
|
readqsize = nr_bufs;
|
|
}
|
|
|
|
block_spec = (rip->i_mode & I_TYPE) == I_BLOCK_SPECIAL;
|
|
if (block_spec)
|
|
dev = (dev_t) rip->i_block[0];
|
|
else
|
|
dev = rip->i_dev;
|
|
|
|
assert(dev != NO_DEV);
|
|
block_size = get_block_size(dev);
|
|
|
|
block = baseblock;
|
|
|
|
fragment = position % block_size;
|
|
position -= fragment;
|
|
position_running = position;
|
|
bytes_ahead += fragment;
|
|
blocks_ahead = (bytes_ahead + block_size - 1) / block_size;
|
|
|
|
if(block_spec)
|
|
bp = get_block(dev, block, PREFETCH);
|
|
else
|
|
bp = lmfs_get_block_ino(dev, block, PREFETCH, rip->i_num, position);
|
|
|
|
|
|
assert(bp != NULL);
|
|
if (lmfs_dev(bp) != NO_DEV) return(bp);
|
|
|
|
/* The best guess for the number of blocks to prefetch: A lot.
|
|
* It is impossible to tell what the device looks like, so we don't even
|
|
* try to guess the geometry, but leave it to the driver.
|
|
*
|
|
* The floppy driver can read a full track with no rotational delay, and it
|
|
* avoids reading partial tracks if it can, so handing it enough buffers to
|
|
* read two tracks is perfect. (Two, because some diskette types have
|
|
* an odd number of sectors per track, so a block may span tracks.)
|
|
*
|
|
* The disk drivers don't try to be smart. With todays disks it is
|
|
* impossible to tell what the real geometry looks like, so it is best to
|
|
* read as much as you can. With luck the caching on the drive allows
|
|
* for a little time to start the next read.
|
|
*
|
|
* The current solution below is a bit of a hack, it just reads blocks from
|
|
* the current file position hoping that more of the file can be found. A
|
|
* better solution must look at the already available
|
|
* indirect blocks (but don't call read_map!).
|
|
*/
|
|
|
|
if (block_spec && rip->i_size == 0) {
|
|
blocks_left = (block_t) NR_IOREQS;
|
|
} else {
|
|
blocks_left = (block_t) (rip->i_size-ex64lo(position)+(block_size-1)) /
|
|
block_size;
|
|
|
|
/* Go for the first indirect block if we are in its neighborhood. */
|
|
if (!block_spec) {
|
|
ind1_pos = (EXT2_NDIR_BLOCKS) * block_size;
|
|
if ((off_t) ex64lo(position) <= ind1_pos && rip->i_size > ind1_pos) {
|
|
blocks_ahead++;
|
|
blocks_left++;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* No more than the maximum request. */
|
|
if (blocks_ahead > NR_IOREQS) blocks_ahead = NR_IOREQS;
|
|
|
|
/* Read at least the minimum number of blocks, but not after a seek. */
|
|
if (blocks_ahead < BLOCKS_MINIMUM && rip->i_seek == NO_SEEK)
|
|
blocks_ahead = BLOCKS_MINIMUM;
|
|
|
|
/* Can't go past end of file. */
|
|
if (blocks_ahead > blocks_left) blocks_ahead = blocks_left;
|
|
|
|
read_q_size = 0;
|
|
|
|
/* Acquire block buffers. */
|
|
for (;;) {
|
|
block_t thisblock;
|
|
read_q[read_q_size++] = bp;
|
|
|
|
if (--blocks_ahead == 0) break;
|
|
|
|
/* Don't trash the cache, leave 4 free. */
|
|
if (lmfs_bufs_in_use() >= nr_bufs - 4) break;
|
|
|
|
block++;
|
|
position_running += block_size;
|
|
|
|
if(!block_spec &&
|
|
(thisblock = read_map(rip, (off_t) ex64lo(position_running), 1)) != NO_BLOCK) {
|
|
bp = lmfs_get_block_ino(dev, thisblock, PREFETCH, rip->i_num, position_running);
|
|
} else {
|
|
bp = get_block(dev, block, PREFETCH);
|
|
}
|
|
if (lmfs_dev(bp) != NO_DEV) {
|
|
/* Oops, block already in the cache, get out. */
|
|
put_block(bp, FULL_DATA_BLOCK);
|
|
break;
|
|
}
|
|
}
|
|
lmfs_rw_scattered(dev, read_q, read_q_size, READING);
|
|
|
|
if(block_spec)
|
|
return get_block(dev, baseblock, NORMAL);
|
|
return(lmfs_get_block_ino(dev, baseblock, NORMAL, rip->i_num, position));
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* fs_getdents *
|
|
*===========================================================================*/
|
|
int fs_getdents(void)
|
|
{
|
|
#define GETDENTS_BUFSIZE (sizeof(struct dirent) + EXT2_NAME_MAX + 1)
|
|
#define GETDENTS_ENTRIES 8
|
|
static char getdents_buf[GETDENTS_BUFSIZE * GETDENTS_ENTRIES];
|
|
struct inode *rip;
|
|
int o, r, done;
|
|
unsigned int block_size, len, reclen;
|
|
ino_t ino;
|
|
cp_grant_id_t gid;
|
|
size_t size, tmpbuf_off, userbuf_off;
|
|
off_t pos, off, block_pos, new_pos, ent_pos;
|
|
struct buf *bp;
|
|
struct ext2_disk_dir_desc *d_desc;
|
|
struct dirent *dep;
|
|
|
|
ino = (ino_t) fs_m_in.REQ_INODE_NR;
|
|
gid = (gid_t) fs_m_in.REQ_GRANT;
|
|
size = (size_t) fs_m_in.REQ_MEM_SIZE;
|
|
pos = (off_t) fs_m_in.REQ_SEEK_POS_LO;
|
|
|
|
/* Check whether the position is properly aligned */
|
|
if ((unsigned int) pos % DIR_ENTRY_ALIGN)
|
|
return(ENOENT);
|
|
|
|
if ((rip = get_inode(fs_dev, ino)) == NULL)
|
|
return(EINVAL);
|
|
|
|
block_size = rip->i_sp->s_block_size;
|
|
off = (pos % block_size); /* Offset in block */
|
|
block_pos = pos - off;
|
|
done = FALSE; /* Stop processing directory blocks when done is set */
|
|
|
|
memset(getdents_buf, '\0', sizeof(getdents_buf)); /* Avoid leaking any data */
|
|
tmpbuf_off = 0; /* Offset in getdents_buf */
|
|
userbuf_off = 0; /* Offset in the user's buffer */
|
|
|
|
/* The default position for the next request is EOF. If the user's buffer
|
|
* fills up before EOF, new_pos will be modified. */
|
|
new_pos = rip->i_size;
|
|
|
|
for (; block_pos < rip->i_size; block_pos += block_size) {
|
|
off_t temp_pos = block_pos;
|
|
/* Since directories don't have holes, 'bp' cannot be NULL. */
|
|
bp = get_block_map(rip, block_pos); /* get a dir block */
|
|
assert(bp != NULL);
|
|
assert(bp != NULL);
|
|
|
|
/* Search a directory block. */
|
|
d_desc = (struct ext2_disk_dir_desc*) &b_data(bp);
|
|
|
|
/* we need to seek to entry at off bytes.
|
|
* when NEXT_DISC_DIR_POS == block_size it's last dentry.
|
|
*/
|
|
for (; temp_pos + conv2(le_CPU, d_desc->d_rec_len) <= pos
|
|
&& NEXT_DISC_DIR_POS(d_desc, &b_data(bp)) < block_size;
|
|
d_desc = NEXT_DISC_DIR_DESC(d_desc)) {
|
|
temp_pos += conv2(le_CPU, d_desc->d_rec_len);
|
|
}
|
|
|
|
for (; CUR_DISC_DIR_POS(d_desc, &b_data(bp)) < block_size;
|
|
d_desc = NEXT_DISC_DIR_DESC(d_desc)) {
|
|
if (d_desc->d_ino == 0)
|
|
continue; /* Entry is not in use */
|
|
|
|
if (d_desc->d_name_len > NAME_MAX ||
|
|
d_desc->d_name_len > EXT2_NAME_MAX) {
|
|
len = min(NAME_MAX, EXT2_NAME_MAX);
|
|
} else {
|
|
len = d_desc->d_name_len;
|
|
}
|
|
|
|
/* Compute record length */
|
|
reclen = offsetof(struct dirent, d_name) + len + 1;
|
|
o = (reclen % sizeof(long));
|
|
if (o != 0)
|
|
reclen += sizeof(long) - o;
|
|
|
|
/* Need the position of this entry in the directory */
|
|
ent_pos = block_pos + ((char *)d_desc - b_data(bp));
|
|
|
|
if (userbuf_off + tmpbuf_off + reclen >= size) {
|
|
/* The user has no space for one more record */
|
|
done = TRUE;
|
|
|
|
/* Record the position of this entry, it is the
|
|
* starting point of the next request (unless the
|
|
* position is modified with lseek).
|
|
*/
|
|
new_pos = ent_pos;
|
|
break;
|
|
}
|
|
|
|
if (tmpbuf_off + reclen >= GETDENTS_BUFSIZE*GETDENTS_ENTRIES) {
|
|
r = sys_safecopyto(VFS_PROC_NR, gid,
|
|
(vir_bytes) userbuf_off,
|
|
(vir_bytes) getdents_buf,
|
|
(size_t) tmpbuf_off);
|
|
if (r != OK) {
|
|
put_inode(rip);
|
|
return(r);
|
|
}
|
|
userbuf_off += tmpbuf_off;
|
|
tmpbuf_off = 0;
|
|
}
|
|
|
|
dep = (struct dirent *) &getdents_buf[tmpbuf_off];
|
|
dep->d_ino = conv4(le_CPU, d_desc->d_ino);
|
|
dep->d_off = ent_pos;
|
|
dep->d_reclen = (unsigned short) reclen;
|
|
memcpy(dep->d_name, d_desc->d_name, len);
|
|
dep->d_name[len] = '\0';
|
|
tmpbuf_off += reclen;
|
|
}
|
|
|
|
put_block(bp, DIRECTORY_BLOCK);
|
|
if (done)
|
|
break;
|
|
}
|
|
|
|
if (tmpbuf_off != 0) {
|
|
r = sys_safecopyto(VFS_PROC_NR, gid, (vir_bytes) userbuf_off,
|
|
(vir_bytes) getdents_buf, (size_t) tmpbuf_off);
|
|
if (r != OK) {
|
|
put_inode(rip);
|
|
return(r);
|
|
}
|
|
|
|
userbuf_off += tmpbuf_off;
|
|
}
|
|
|
|
if (done && userbuf_off == 0)
|
|
r = EINVAL; /* The user's buffer is too small */
|
|
else {
|
|
fs_m_out.RES_NBYTES = userbuf_off;
|
|
fs_m_out.RES_SEEK_POS_LO = new_pos;
|
|
rip->i_update |= ATIME;
|
|
rip->i_dirt = IN_DIRTY;
|
|
r = OK;
|
|
}
|
|
|
|
put_inode(rip); /* release the inode */
|
|
return(r);
|
|
}
|