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[PATCH] fat: support a truncate() for expanding size (generic_cont_expand)

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This patch changes generic_cont_expand(), in order to share the code
with fatfs.

  - Use vmtruncate() if ->prepare_write() returns a error.

Even if ->prepare_write() returns an error, it may already have added some
blocks.  So, this truncates blocks outside of ->i_size by vmtruncate().

  - Add generic_cont_expand_simple().

The generic_cont_expand_simple() assumes that ->prepare_write() can handle
the block boundary.  With this, we don't need to care the extra byte.

And for expanding a file size by truncate(), fatfs uses the
added generic_cont_expand_simple().

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
OGAWA Hirofumi
2006-01-08 01:02:13 -08:00
committed by Linus Torvalds
parent 268fc16e34
commit 05eb0b51fb
3 changed files with 76 additions and 18 deletions
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31
fs/fat/file.c
View File

@@ -11,6 +11,7 @@
#include <linux/msdos_fs.h>
#include <linux/smp_lock.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
int fat_generic_ioctl(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg)
@@ -124,6 +125,24 @@ struct file_operations fat_file_operations = {
.sendfile = generic_file_sendfile,
};
static int fat_cont_expand(struct inode *inode, loff_t size)
{
struct address_space *mapping = inode->i_mapping;
loff_t start = inode->i_size, count = size - inode->i_size;
int err;
err = generic_cont_expand_simple(inode, size);
if (err)
goto out;
inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
if (IS_SYNC(inode))
err = sync_page_range_nolock(inode, mapping, start, count);
out:
return err;
}
int fat_notify_change(struct dentry *dentry, struct iattr *attr)
{
struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
@@ -132,11 +151,17 @@ int fat_notify_change(struct dentry *dentry, struct iattr *attr)
lock_kernel();
/* FAT cannot truncate to a longer file */
/*
* Expand the file. Since inode_setattr() updates ->i_size
* before calling the ->truncate(), but FAT needs to fill the
* hole before it.
*/
if (attr->ia_valid & ATTR_SIZE) {
if (attr->ia_size > inode->i_size) {
error = -EPERM;
goto out;
error = fat_cont_expand(inode, attr->ia_size);
if (error || attr->ia_valid == ATTR_SIZE)
goto out;
attr->ia_valid &= ~ATTR_SIZE;
}
}