[PATCH] vfat/rw for kernel 2.3.xx

Thierry Vignaud (tvignaud@mandrakesoft.com)
Mon, 26 Jul 1999 13:54:40 +0000

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Hi.

Here are two patches :
* the first was for 2.3.7, it enables to read vfat (mount in ro only,
write/execute lock up process)
* the other one is for 2.3.11, it enables to behave right for reads as
for writes. It seems safe but i won't garrant that it 'll not destroy
your data.
If you use a 2.3.xx kernel, you have to know what to wait for...

-- 
MandrakeSoft          http://www.mandrakesoft.com/
			         	 --Thierry
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diff -ru linux/fs/fat/fatfs_syms.c linux-2.3.7/fs/fat/fatfs_syms.c
--- linux/fs/fat/fatfs_syms.c	Wed May 19 05:13:04 1999
+++ linux-2.3.7/fs/fat/fatfs_syms.c	Tue Jun 22 15:28:18 1999
@@ -28,7 +28,6 @@
 EXPORT_SYMBOL(fat_dir_operations);
 EXPORT_SYMBOL(fat_esc2uni);
 EXPORT_SYMBOL(fat_file_read);
-EXPORT_SYMBOL(fat_file_write);
 EXPORT_SYMBOL(fat_fs_panic);
 EXPORT_SYMBOL(fat__get_entry);
 EXPORT_SYMBOL(fat_lock_creation);
diff -ru linux/fs/fat/file.c linux-2.3.7/fs/fat/file.c
--- linux/fs/fat/file.c	Sun Feb 28 18:47:37 1999
+++ linux-2.3.7/fs/fat/file.c	Tue Jun 22 15:14:27 1999
@@ -57,7 +57,7 @@
 	NULL,			/* rename */
 	NULL,			/* readlink */
 	NULL,			/* follow_link */
-	generic_readpage,	/* readpage */
+	block_read_full_page,	/* readpage */
 	NULL,			/* writepage */
 	fat_bmap,		/* bmap */
 	fat_truncate,		/* truncate */
@@ -107,7 +107,7 @@
 	NULL,			/* rename */
 	NULL,			/* readlink */
 	NULL,			/* follow_link */
-	generic_readpage,	/* readpage */
+	block_read_full_page,	/* readpage */
 	NULL,			/* writepage */
 	NULL,			/* bmap */
 	fat_truncate,		/* truncate */
@@ -330,124 +330,22 @@
 		return fat_file_read_text(filp, buf, count, ppos);
 	return generic_file_read(filp, buf, count, ppos);
 }
-/*
-	Write to a file either from user space
-*/
-ssize_t fat_file_write(
-	struct file *filp,
-	const char *buf,
-	size_t count,
-	loff_t *ppos)
+
+static long fat_write_one_page(struct file *file, struct page *page, unsigned long offset, unsigned long bytes, const char *buf)
 {
-	struct inode *inode = filp->f_dentry->d_inode;
-	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;
+    return block_write_partial_page(file, page, offset, bytes, buf, fat_getblk);
+}
 
-	PRINTK(("fat_file_write: dentry=%p, inode=%p, ino=%ld\n",
-		filp->f_dentry, inode, inode->i_ino));
-	if (!inode) {
-		printk("fat_file_write: inode = NULL\n");
-		return -EINVAL;
-	}
-        if (MSDOS_SB(sb)->cvf_format &&
-	    MSDOS_SB(sb)->cvf_format->cvf_file_write)
-		return MSDOS_SB(sb)->cvf_format
-			->cvf_file_write(filp,buf,count,ppos);
 
-	/* S_ISLNK allows for UMSDOS. Should never happen for normal MSDOS */
-	if (!S_ISREG(inode->i_mode) && !S_ISLNK(inode->i_mode)) {
-		printk("fat_file_write: mode = %07o\n",inode->i_mode);
-		return -EINVAL;
-	}
-	/* system files may be 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.
+ * Write to a file (through the page cache).
  */
-	if (filp->f_flags & O_APPEND)
-		*ppos = inode->i_size;
-	if (count == 0)
-		return 0;
-	if (*ppos + count > 0x7FFFFFFFLL) {
-		count = 0x7FFFFFFFLL-*ppos;
-		if (!count)
-			return -EFBIG;
-	}
-
-	error = carry = 0;
-	for (start = buf; count || carry; count -= size) {
-		while (!(sector = fat_smap(inode,*ppos >> SECTOR_BITS)))
-			if ((error = fat_add_cluster(inode)) < 0) break;
-		if (error) {
-			fat_truncate(inode);
-			break;
-		}
-		offset = *ppos & (SECTOR_SIZE-1);
-		size = MIN(SECTOR_SIZE-offset,MAX(carry,count));
-		if (binary_mode
-			&& offset == 0
-			&& (size == SECTOR_SIZE
-				|| *ppos + 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 = fat_getblk(sb,sector))){
-				error = -EIO;
-				break;
-			}
-		} else if (!(bh = fat_bread(sb,sector))) {
-			error = -EIO;
-			break;
-		}
-		if (binary_mode) {
-			copy_from_user(bh->b_data+offset,buf,written = size);
-			buf += size;
-		} else {
-			written = left = SECTOR_SIZE-offset;
-			to = (char *) bh->b_data+(*ppos & (SECTOR_SIZE-1));
-			if (carry) {
-				*to++ = '\n';
-				left--;
-				carry = 0;
-			}
-			for (size = 0; size < count && left; size++) {
-				get_user(ch, buf++);
-				if (ch == '\n') {
-					*to++ = '\r';
-					left--;
-				}
-				if (!left) carry = 1;
-				else {
-					*to++ = ch;
-					left--;
-				}
-			}
-			written -= left;
-		}
-		update_vm_cache(inode, *ppos, bh->b_data + (*ppos & (SECTOR_SIZE-1)), written);
-		*ppos += written;
-		if (*ppos > inode->i_size) {
-			inode->i_size = *ppos;
-			mark_inode_dirty(inode);
-		}
-		fat_set_uptodate(sb, bh, 1);
-		fat_mark_buffer_dirty(sb, bh, 0);
-		fat_brelse(sb, bh);
-	}
-	if (start == buf)
-		return error;
-	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
-	MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
-	mark_inode_dirty(inode);
-	return buf-start;
+static ssize_t
+fat_file_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
+{
+    return generic_file_write(file, buf, count, ppos, fat_write_one_page);
 }
+
 
 void fat_truncate(struct inode *inode)
 {


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diff -ruN linux/fs/fat/fatfs_syms.c fs/fat/fatfs_syms.c
--- linux/fs/fat/fatfs_syms.c	Fri May 14 08:18:20 1999
+++ fs/fat/fatfs_syms.c	Mon Jul 26 12:07:18 1999
@@ -28,7 +28,6 @@
 EXPORT_SYMBOL(fat_dir_operations);
 EXPORT_SYMBOL(fat_esc2uni);
 EXPORT_SYMBOL(fat_file_read);
-EXPORT_SYMBOL(fat_file_write);
 EXPORT_SYMBOL(fat_fs_panic);
 EXPORT_SYMBOL(fat__get_entry);
 EXPORT_SYMBOL(fat_lock_creation);
diff -ruN linux/fs/fat/file.c fs/fat/file.c
--- linux/fs/fat/file.c	Sun Jun 27 19:10:41 1999
+++ fs/fat/file.c	Mon Jul 26 13:54:42 1999
@@ -336,124 +336,21 @@
 		return fat_file_read_text(filp, buf, count, ppos);
 	return generic_file_read(filp, buf, count, ppos);
 }
-/*
-	Write to a file either from user space
-*/
-ssize_t fat_file_write(
-	struct file *filp,
-	const char *buf,
-	size_t count,
-	loff_t *ppos)
+
+static long fat_write_one_page(struct file *file, struct page *page, unsigned long offset, unsigned long bytes, const char *buf)
 {
-	struct inode *inode = filp->f_dentry->d_inode;
-	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;
+    return block_write_partial_page(file, page, offset, bytes, buf);
+}
 
-	PRINTK(("fat_file_write: dentry=%p, inode=%p, ino=%ld\n",
-		filp->f_dentry, inode, inode->i_ino));
-	if (!inode) {
-		printk("fat_file_write: inode = NULL\n");
-		return -EINVAL;
-	}
-        if (MSDOS_SB(sb)->cvf_format &&
-	    MSDOS_SB(sb)->cvf_format->cvf_file_write)
-		return MSDOS_SB(sb)->cvf_format
-			->cvf_file_write(filp,buf,count,ppos);
 
-	/* S_ISLNK allows for UMSDOS. Should never happen for normal MSDOS */
-	if (!S_ISREG(inode->i_mode) && !S_ISLNK(inode->i_mode)) {
-		printk("fat_file_write: mode = %07o\n",inode->i_mode);
-		return -EINVAL;
-	}
-	/* system files may be 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.
+ * Write to a file (through the page cache).
  */
-	if (filp->f_flags & O_APPEND)
-		*ppos = inode->i_size;
-	if (count == 0)
-		return 0;
-	if (*ppos + count > 0x7FFFFFFFLL) {
-		count = 0x7FFFFFFFLL-*ppos;
-		if (!count)
-			return -EFBIG;
-	}
-
-	error = carry = 0;
-	for (start = buf; count || carry; count -= size) {
-		while (!(sector = fat_smap(inode,*ppos >> SECTOR_BITS)))
-			if ((error = fat_add_cluster(inode)) < 0) break;
-		if (error) {
-			fat_truncate(inode);
-			break;
-		}
-		offset = *ppos & (SECTOR_SIZE-1);
-		size = MIN(SECTOR_SIZE-offset,MAX(carry,count));
-		if (binary_mode
-			&& offset == 0
-			&& (size == SECTOR_SIZE
-				|| *ppos + 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 = fat_getblk(sb,sector))){
-				error = -EIO;
-				break;
-			}
-		} else if (!(bh = fat_bread(sb,sector))) {
-			error = -EIO;
-			break;
-		}
-		if (binary_mode) {
-			copy_from_user(bh->b_data+offset,buf,written = size);
-			buf += size;
-		} else {
-			written = left = SECTOR_SIZE-offset;
-			to = (char *) bh->b_data+(*ppos & (SECTOR_SIZE-1));
-			if (carry) {
-				*to++ = '\n';
-				left--;
-				carry = 0;
-			}
-			for (size = 0; size < count && left; size++) {
-				get_user(ch, buf++);
-				if (ch == '\n') {
-					*to++ = '\r';
-					left--;
-				}
-				if (!left) carry = 1;
-				else {
-					*to++ = ch;
-					left--;
-				}
-			}
-			written -= left;
-		}
-		update_vm_cache(inode, *ppos, bh->b_data + (*ppos & (SECTOR_SIZE-1)), written);
-		*ppos += written;
-		if (*ppos > inode->i_size) {
-			inode->i_size = *ppos;
-			mark_inode_dirty(inode);
-		}
-		fat_set_uptodate(sb, bh, 1);
-		fat_mark_buffer_dirty(sb, bh, 0);
-		fat_brelse(sb, bh);
-	}
-	if (start == buf)
-		return error;
-	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
-	MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
-	mark_inode_dirty(inode);
-	return buf-start;
+static ssize_t fat_file_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
+{
+    return generic_file_write(file, buf, count, ppos, fat_write_one_page);
 }
+
 
 void fat_truncate(struct inode *inode)
 {


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