/*
* s5fs_dirtypage:
* A hook; an attempt is being made to dirty the page
* belonging to 'vnode' that contains 'offset'. (If the
* underlying fs supports sparse blocks/pages, and the page
* containing this offset is currently sparse, this is
* where an attempt should be made to allocate a block in
* the underlying fs for that block/page). Return zero on
* success and nonzero otherwise.
* param vnode: the pointer to the vnode object
* param offset: the arbitrary offset of that file (bytes offset)
* return: the block number or 0; negative number for failure
*/
static int
s5fs_dirtypage(vnode_t *vnode, off_t offset)
{
dbg(DBG_S5FS, "{\n");
KASSERT(vnode != NULL);
int disk_number = 0;
int sparse = 0;
if ((sparse = s5_seek_to_block(vnode, offset, 0)) < 0)
{
return sparse;
}
else if (sparse > 0)
{
/* find the page */
return 0;
}
if ((disk_number = s5_seek_to_block(vnode, offset, 1)) < 0)
{
return disk_number;
}
/* Dirty the page */
s5_dirty_inode(VNODE_TO_S5FS(vnode), VNODE_TO_S5INODE(vnode));
dbg(DBG_S5FS, "}\n");
return 0;
}
/*
* s5fs_fillpage:
* Read the page of 'vnode' containing 'offset' into the
* page-aligned and page-sized buffer pointed to by
* 'pagebuf'.
* param *vnode: the pointer to the vnode object
* param offset: the arbitrary offset of that file (bytes offset)
* param pagebuf: the buffer for storing the data you have read
* return: number of bytes that have been read, or negative number for errors
*/
static int
s5fs_fillpage(vnode_t *vnode, off_t offset, void *pagebuf)
{
dbg(DBG_S5FS, "{\n");
KASSERT(vnode != NULL);
KASSERT(pagebuf != NULL);
int disk_number = 0;
if ((disk_number = s5_seek_to_block(vnode, offset, 0)) < 0)
{
return disk_number;
}
if (disk_number == 0)
{
memset(pagebuf, 0, PAGE_SIZE);
return 0;
}
/* If the disk_number is zero, ignore pagebuf */
int ret = VNODE_TO_S5FS(vnode)->s5f_bdev->bd_ops->read_block(
VNODE_TO_S5FS(vnode)->s5f_bdev, pagebuf, disk_number, 1);
dbg(DBG_S5FS, "}\n");
return ret;
}
/*
* if this offset is NOT within a sparse region of the file
* return 0;
*
* attempt to make the region containing this offset no longer
* sparse
* - attempt to allocate a free block
* - if no free blocks available, return -ENOSPC
* - associate this block with the inode; alter the inode as
* appropriate
* - dirty the page containing this inode
*
* Much of this can be done with s5_seek_to_block()
*/
static int
s5fs_dirtypage(vnode_t *vnode, off_t offset)
{
int blocknum = s5_seek_to_block(vnode, offset, 0);
switch (blocknum){
case -EFBIG:
case -ENOSPC:
return blocknum;
default:
/* do nothing */;
}
KASSERT(blocknum >= 0 && "forgot to handle an error case");
return (blocknum == 0) ? s5_seek_to_block(vnode, offset, 1) : 0;
}
/*
* Like fillpage, but for writing.
*/
static int
s5fs_cleanpage(vnode_t *vnode, off_t offset, void *pagebuf)
{
int blocknum = s5_seek_to_block(vnode, offset, 1);
switch (blocknum){
case -EFBIG:
case -ENOSPC:
return blocknum;
default:
/* do nothing */;
}
KASSERT(blocknum > 0 && "forgot to handle an error case");
blockdev_t *bd = ((s5fs_t *) vnode->vn_fs->fs_i)->s5f_bdev;
return bd->bd_ops->write_block(bd, (char *) pagebuf, blocknum, 1/*S5_BLOCK_SIZE*/);
}
/*
* s5fs_cleanpage:
* Write the contents of the page-aligned and page-sized
* buffer pointed to by 'pagebuf' to the page of 'vnode'
* containing 'offset'.
* param *vnode: the pointer to the vnode object
* param offset: the arbitrary offset of that file (bytes offset)
* param pagebuf: the source buffer
* return: number of bytes that have been written, or negative number for errors
*/
static int
s5fs_cleanpage(vnode_t *vnode, off_t offset, void *pagebuf)
{
dbg(DBG_S5FS, "{\n");
KASSERT(vnode != NULL);
KASSERT(pagebuf != NULL);
/* Alloc */
int disk_number = 0;
if ((disk_number = s5_seek_to_block(vnode, offset, 0)) < 0)
{
return disk_number;/* error */
}
/* If the disk_number is zero, ignore pagebuf */
int ret = VNODE_TO_S5FS(vnode)->s5f_bdev->bd_ops->write_block(
VNODE_TO_S5FS(vnode)->s5f_bdev, pagebuf, disk_number, 1);
dbg(DBG_S5FS, "}\n");
return ret;
}
/*
* See the comment in vnode.h for what is expected of this function.
*
* You'll probably want to use s5_seek_to_block and the device's
* read_block function.
*/
static int
s5fs_fillpage(vnode_t *vnode, off_t offset, void *pagebuf)
{
int blocknum = s5_seek_to_block(vnode, offset, 0);
switch (blocknum){
case -EFBIG:
case -ENOSPC:
return blocknum;
default:
/* do nothing */;
}
KASSERT(blocknum >= 0 && "forgot to handle an error case");
if (blocknum == 0){
bytedev_t *bd = bytedev_lookup(MEM_ZERO_DEVID);
return bd->cd_ops->read(bd, 0, pagebuf, S5_BLOCK_SIZE);
} else {
blockdev_t *bd = ((s5fs_t *) vnode->vn_fs->fs_i)->s5f_bdev;
return bd->bd_ops->read_block(bd, (char *) pagebuf, blocknum, 1/*S5_BLOCK_SIZE*/);
}
}
