patch-1.3.60 linux/fs/msdos/file.c

• Lines: 376
• Date: Thu Jan 1 02:00:00 1970
• Orig file: v1.3.59/linux/fs/msdos/file.c
• Orig date: Thu Jan 4 21:54:58 1996

diff -u --recursive --new-file v1.3.59/linux/fs/msdos/file.c linux/fs/msdos/file.c
@@ -1,375 +0,0 @@
-/*
- *  linux/fs/msdos/file.c
- *
- *  Written 1992,1993 by Werner Almesberger
- *
- *  MS-DOS regular file handling primitives
- */
-
-#include <linux/sched.h>
-#include <linux/locks.h>
-#include <linux/fs.h>
-#include <linux/msdos_fs.h>
-#include <linux/errno.h>
-#include <linux/fcntl.h>
-#include <linux/stat.h>
-#include <linux/string.h>
-
-#include <asm/segment.h>
-#include <asm/system.h>
-
-#include "msbuffer.h"
-
-#define MIN(a,b) (((a) < (b)) ? (a) : (b))
-#define MAX(a,b) (((a) > (b)) ? (a) : (b))
-
-#define PRINTK(x)
-#define Printk(x) printk x
-
-static struct file_operations msdos_file_operations = {
-	NULL,			/* lseek - default */
-	msdos_file_read,	/* read */
-	msdos_file_write,	/* write */
-	NULL,			/* readdir - bad */
-	NULL,			/* select - default */
-	NULL,			/* ioctl - default */
-	generic_mmap,		/* mmap */
-	NULL,			/* no special open is needed */
-	NULL,			/* release */
-	file_fsync		/* fsync */
-};
-
-struct inode_operations msdos_file_inode_operations = {
-	&msdos_file_operations,	/* default file operations */
-	NULL,			/* create */
-	NULL,			/* lookup */
-	NULL,			/* link */
-	NULL,			/* unlink */
-	NULL,			/* symlink */
-	NULL,			/* mkdir */
-	NULL,			/* rmdir */
-	NULL,			/* mknod */
-	NULL,			/* rename */
-	NULL,			/* readlink */
-	NULL,			/* follow_link */
-	generic_readpage,	/* readpage */
-	NULL,			/* writepage */
-	msdos_bmap,		/* bmap */
-	msdos_truncate,		/* truncate */
-	NULL,			/* permission */
-	NULL			/* smap */
-};
-/* #Specification: msdos / special devices / mmap	
-	Mmapping does work because a special mmap is provide in that case.
-	Note that it is much less efficient than the generic_mmap normally
-	used since it allocate extra buffer. generic_mmap is used for
-	normal device (512 bytes hardware sectors).
-*/
-static struct file_operations msdos_file_operations_1024 = {
-	NULL,			/* lseek - default */
-	msdos_file_read,	/* read */
-	msdos_file_write,	/* write */
-	NULL,			/* readdir - bad */
-	NULL,			/* select - default */
-	NULL,			/* ioctl - default */
-	msdos_mmap,		/* mmap */
-	NULL,			/* no special open is needed */
-	NULL,			/* release */
-	file_fsync		/* fsync */
-};
-
-/* #Specification: msdos / special devices / swap file
-	Swap file can't work on special devices with a large sector
-	size (1024 bytes hard sector). Those devices have a weird
-	MsDOS filesystem layout. Generally a single hardware sector
-	may contain 2 unrelated logical sector. This mean that there is
-	no easy way to do a mapping between disk sector of a file and virtual
-	memory. So swap file is difficult (not available right now)
-	on those devices. Off course, Ext2 does not have this problem.
-*/
-struct inode_operations msdos_file_inode_operations_1024 = {
-	&msdos_file_operations_1024,	/* default file operations */
-	NULL,			/* create */
-	NULL,			/* lookup */
-	NULL,			/* link */
-	NULL,			/* unlink */
-	NULL,			/* symlink */
-	NULL,			/* mkdir */
-	NULL,			/* rmdir */
-	NULL,			/* mknod */
-	NULL,			/* rename */
-	NULL,			/* readlink */
-	NULL,			/* follow_link */
-	NULL,			/* readpage */
-	NULL,			/* writepage */
-	NULL,			/* bmap */
-	msdos_truncate,		/* truncate */
-	NULL,			/* permission */
-	NULL			/* smap */
-};
-
-#define MSDOS_PREFETCH	32
-struct msdos_pre {
-	int file_sector;/* Next sector to read in the prefetch table */
-			/* This is relative to the file, not the disk */
-	struct buffer_head *bhlist[MSDOS_PREFETCH];	/* All buffers needed */
-	int nblist;	/* Number of buffers in bhlist */
-	int nolist;	/* index in bhlist */
-};
-/*
-	Order the prefetch of more sectors.
-*/
-static void msdos_prefetch (
-	struct inode *inode,
-	struct msdos_pre *pre,
-	int nb)		/* How many must be prefetch at once */
-{
-	struct super_block *sb = inode->i_sb;
-	struct buffer_head *bhreq[MSDOS_PREFETCH];	/* Buffers not */
-												/* already read */
-	int nbreq=0;			/* Number of buffers in bhreq */
-	int i;
-	for (i=0; i<nb; i++){
-		int sector = msdos_smap(inode,pre->file_sector);
-		if (sector != 0){
-			struct buffer_head *bh;
-			PRINTK (("fsector2 %d -> %d\n",pre->file_sector-1,sector));
-			pre->file_sector++;
-			bh = getblk(inode->i_dev,sector,SECTOR_SIZE);
-			if (bh == NULL)	break;
-			pre->bhlist[pre->nblist++] = bh;
-			if (!msdos_is_uptodate(sb,bh)) bhreq[nbreq++] = bh;
-		}else{
-			break;
-		}
-	}
-	if (nbreq > 0) msdos_ll_rw_block (sb,READ,nbreq,bhreq);
-	for (i=pre->nblist; i<MSDOS_PREFETCH; i++) pre->bhlist[i] = NULL;
-}
-
-/*
-	Read a file into user space
-*/
-int msdos_file_read(
-	struct inode *inode,
-	struct file *filp,
-	char *buf,
-	int count)
-{
-	struct super_block *sb = inode->i_sb;
-	char *start = buf;
-	char *end   = buf + count;
-	int i;
-	int left_in_file;
-	struct msdos_pre pre;
-		
-
-	if (!inode) {
-		printk("msdos_file_read: inode = NULL\n");
-		return -EINVAL;
-	}
-	/* S_ISLNK allows for UMSDOS. Should never happen for normal MSDOS */
-	if (!S_ISREG(inode->i_mode) && !S_ISLNK(inode->i_mode)) {
-		printk("msdos_file_read: mode = %07o\n",inode->i_mode);
-		return -EINVAL;
-	}
-	if (filp->f_pos >= inode->i_size || count <= 0) return 0;
-	/*
-		Tell the buffer cache which block we expect to read in advance
-		Since we are limited with the stack, we preread only MSDOS_PREFETCH
-		because we have to keep the result into the local
-		arrays pre.bhlist and bhreq.
-		
-		Each time we process one block in bhlist, we replace
-		it by a new prefetch block if needed.
-	*/
-	PRINTK (("#### ino %ld pos %ld size %ld count %d\n",inode->i_ino,filp->f_pos,inode->i_size,count));
-	{
-		/*
-			We must prefetch complete block, so we must
-			take in account the offset in the first block.
-		*/
-		int count_max = (filp->f_pos & (SECTOR_SIZE-1)) + count;
-		int   to_reada;	/* How many block to read all at once */
-		pre.file_sector = filp->f_pos >> SECTOR_BITS;
-		to_reada = count_max / SECTOR_SIZE;
-		if (count_max & (SECTOR_SIZE-1)) to_reada++;
-		if (filp->f_reada || !MSDOS_I(inode)->i_binary){
-			/* Doing a read ahead on ascii file make sure we always */
-			/* pre read enough, since we don't know how many blocks */
-			/* we really need */
-			int ahead = read_ahead[MAJOR(inode->i_dev)];
-			PRINTK (("to_reada %d ahead %d\n",to_reada,ahead));
-			if (ahead == 0) ahead = 8;
-			to_reada += ahead;
-		}
-		if (to_reada > MSDOS_PREFETCH) to_reada = MSDOS_PREFETCH;
-		pre.nblist = 0;
-		msdos_prefetch (inode,&pre,to_reada);
-	}
-	pre.nolist = 0;
-	PRINTK (("count %d ahead %d nblist %d\n",count,read_ahead[MAJOR(inode->i_dev)],pre.nblist));
-	while ((left_in_file = inode->i_size - filp->f_pos) > 0
-		&& buf < end){
-		struct buffer_head *bh = pre.bhlist[pre.nolist];
-		char *data;
-		int size,offset;
-		if (bh == NULL) break;
-		pre.bhlist[pre.nolist] = NULL;
-		pre.nolist++;
-		if (pre.nolist == MSDOS_PREFETCH/2){
-			memcpy (pre.bhlist,pre.bhlist+MSDOS_PREFETCH/2
-				,(MSDOS_PREFETCH/2)*sizeof(pre.bhlist[0]));
-			pre.nblist -= MSDOS_PREFETCH/2;
-			msdos_prefetch (inode,&pre,MSDOS_PREFETCH/2);
-			pre.nolist = 0;
-		}
-		PRINTK (("file_read pos %ld nblist %d %d %d\n",filp->f_pos,pre.nblist,pre.fetched,count));
-		wait_on_buffer(bh);
-		if (!msdos_is_uptodate(sb,bh)){
-			/* read error  ? */
-			brelse (bh);
-			break;
-		}
-		offset = filp->f_pos & (SECTOR_SIZE-1);
-		data = bh->b_data + offset;
-		size = MIN(SECTOR_SIZE-offset,left_in_file);
-		if (MSDOS_I(inode)->i_binary) {
-			size = MIN(size,end-buf);
-			memcpy_tofs(buf,data,size);
-			buf += size;
-			filp->f_pos += size;
-		}else{
-			for (; size && buf < end; size--) {
-				char ch = *data++;
-				filp->f_pos++;
-				if (ch == 26){
-					filp->f_pos = inode->i_size;
-					break;
-				}else if (ch != '\r'){
-					put_user(ch,buf++);
-				}
-			}
-		}
-		brelse(bh);
-	}
-	PRINTK (("--- %d -> %d\n",count,(int)(buf-start)));
-	for (i=0; i<pre.nblist; i++) brelse (pre.bhlist[i]);
-	if (start == buf) return -EIO;
-	if (!IS_RDONLY(inode)) inode->i_atime = CURRENT_TIME;
-	filp->f_reada = 1;	/* Will be reset if a lseek is done */
-	return buf-start;
-}
-
-/*
-	Write to a file either from user space
-*/
-int msdos_file_write(
-	struct inode *inode,
-	struct file *filp,
-	const char *buf,
-	int count)
-{
-	struct super_block *sb = inode->i_sb;
-	int sector,offset,size,left,written;
-	int error,carry;
-	const char *start;
-	char *to,ch;
-	struct buffer_head *bh;
-	int binary_mode = MSDOS_I(inode)->i_binary;
-
-	if (!inode) {
-		printk("msdos_file_write: inode = NULL\n");
-		return -EINVAL;
-	}
-	/* S_ISLNK allows for UMSDOS. Should never happen for normal MSDOS */
-	if (!S_ISREG(inode->i_mode) && !S_ISLNK(inode->i_mode)) {
-		printk("msdos_file_write: mode = %07o\n",inode->i_mode);
-		return -EINVAL;
-	}
-	/* system files are immutable */
-	if (IS_IMMUTABLE(inode)) return -EPERM;
-/*
- * ok, append may not work when many processes are writing at the same time
- * but so what. That way leads to madness anyway.
- */
-	if (filp->f_flags & O_APPEND) filp->f_pos = inode->i_size;
-	if (count <= 0) return 0;
-	error = carry = 0;
-	for (start = buf; count || carry; count -= size) {
-		while (!(sector = msdos_smap(inode,filp->f_pos >> SECTOR_BITS)))
-			if ((error = msdos_add_cluster(inode)) < 0) break;
-		if (error) {
-			msdos_truncate(inode);
-			break;
-		}
-		offset = filp->f_pos & (SECTOR_SIZE-1);
-		size = MIN(SECTOR_SIZE-offset,MAX(carry,count));
-		if (binary_mode
-			&& offset == 0
-			&& (size == SECTOR_SIZE
-				|| filp->f_pos + size >= inode->i_size)){
-			/* No need to read the block first since we will */
-			/* completely overwrite it */
-			/* or at least write past the end of file */
-			if (!(bh = getblk(inode->i_dev,sector,SECTOR_SIZE))){
-				error = -EIO;
-				break;
-			}
-		}else if (!(bh = bread(inode->i_dev,sector,SECTOR_SIZE))) {
-			error = -EIO;
-			break;
-		}
-		if (binary_mode) {
-			memcpy_fromfs(bh->b_data+offset,buf,written = size);
-			buf += size;
-		}
-		else {
-			written = left = SECTOR_SIZE-offset;
-			to = (char *) bh->b_data+(filp->f_pos & (SECTOR_SIZE-1));
-			if (carry) {
-				*to++ = '\n';
-				left--;
-				carry = 0;
-			}
-			for (size = 0; size < count && left; size++) {
-				if ((ch = get_user(buf++)) == '\n') {
-					*to++ = '\r';
-					left--;
-				}
-				if (!left) carry = 1;
-				else {
-					*to++ = ch;
-					left--;
-				}
-			}
-			written -= left;
-		}
-		filp->f_pos += written;
-		if (filp->f_pos > inode->i_size) {
-			inode->i_size = filp->f_pos;
-			inode->i_dirt = 1;
-		}
-		msdos_set_uptodate(sb,bh,1);
-		mark_buffer_dirty(bh, 0);
-		brelse(bh);
-	}
-	if (start == buf)
-		return error;
-	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
-	MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
-	inode->i_dirt = 1;
-	return buf-start;
-}
-
-void msdos_truncate(struct inode *inode)
-{
-	int cluster;
-
-	/* Why no return value?  Surely the disk could fail... */
-	if (IS_IMMUTABLE(inode)) return /* -EPERM */;
-	cluster = SECTOR_SIZE*MSDOS_SB(inode->i_sb)->cluster_size;
-	(void) fat_free(inode,(inode->i_size+(cluster-1))/cluster);
-	MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
-	inode->i_dirt = 1;
-}