static void *cramfs_read_nand(struct super_block *sb, unsigned int offset, unsigned int len)
{
unsigned i, blocknr, buffer;
char *data;
struct cramfs_sb_info *sbi = sb->s_fs_info;
struct mtd_info *mtd = sbi->mtd;
unsigned mblock, moffset, pblock, maddr;
int retv;
size_t dummy;
if (!len)
return NULL;
blocknr = offset >> PAGE_CACHE_SHIFT;
/* Check if an existing buffer already has the data.. */
for (i = 0; i < READ_BUFFERS; i++) {
unsigned int blk_offset;
if (buffer_dev[i] != sb)
continue;
if (blocknr < buffer_blocknr[i])
continue;
blk_offset = (blocknr - buffer_blocknr[i]) << PAGE_CACHE_SHIFT;
blk_offset += (offset & (PAGE_CACHE_SIZE - 1));
if (blk_offset + len > BUFFER_SIZE)
continue;
return read_buffers[i] + blk_offset;
}
buffer = next_buffer;
next_buffer = NEXT_BUFFER(buffer);
buffer_blocknr[buffer] = blocknr;
buffer_dev[buffer] = sb;
mblock = offset / mtd->erasesize;
moffset = (offset & (mtd->erasesize - 1)) & (~(PAGE_CACHE_SIZE - 1));
offset &= (PAGE_CACHE_SIZE - 1);
pblock = get_block_map(sb, mblock);
maddr = pblock * mtd->erasesize + moffset;
data = read_buffers[buffer];
if (moffset + BUFFER_SIZE <= mtd->erasesize) {
retv = mtd->read(mtd, maddr, BUFFER_SIZE, &dummy, data);
} else {
int read_size;
read_size = mtd->erasesize - moffset;
retv = mtd->read(mtd, maddr, read_size, &dummy, data);
pblock = get_block_map(sb, mblock + 1);
maddr = pblock * mtd->erasesize;
retv = mtd->read(mtd, maddr, (BUFFER_SIZE - read_size), &dummy, data + read_size);
}
return read_buffers[buffer] + offset;
}
/*===========================================================================*
* fs_rdlink *
*===========================================================================*/
int fs_rdlink()
{
struct buf *bp = NULL; /* buffer containing link text */
char* link_text; /* either bp->b_data or rip->i_block */
register struct inode *rip; /* target inode */
register int r; /* return value */
size_t copylen;
copylen = min( (size_t) fs_m_in.REQ_MEM_SIZE, UMAX_FILE_POS);
/* Temporarily open the file. */
if( (rip = get_inode(fs_dev, (ino_t) fs_m_in.REQ_INODE_NR)) == NULL)
return(EINVAL);
if (rip->i_size >= MAX_FAST_SYMLINK_LENGTH) {
/* normal symlink */
if(!(bp = get_block_map(rip, 0))) {
r = EIO;
} else {
link_text = b_data(bp);
r = OK;
}
} else {
/* fast symlink, stored in inode */
link_text = (char*) rip->i_block;
r = OK;
}
if (r == OK) {
/* Passed all checks */
/* We can safely cast to unsigned, because copylen is guaranteed to be
below max file size */
copylen = min( copylen, (unsigned) rip->i_size);
r = sys_safecopyto(VFS_PROC_NR, (cp_grant_id_t) fs_m_in.REQ_GRANT,
(vir_bytes) 0, (vir_bytes) link_text,
(size_t) copylen);
put_block(bp, DIRECTORY_BLOCK);
if (r == OK)
fs_m_out.RES_NBYTES = copylen;
}
put_inode(rip);
return(r);
}
/*===========================================================================*
* fs_rdlink *
*===========================================================================*/
ssize_t fs_rdlink(ino_t ino_nr, struct fsdriver_data *data, size_t bytes)
{
struct buf *bp = NULL; /* buffer containing link text */
char* link_text; /* either bp->b_data or rip->i_block */
register struct inode *rip; /* target inode */
register int r; /* return value */
/* Temporarily open the file. */
if( (rip = get_inode(fs_dev, ino_nr)) == NULL)
return(EINVAL);
if (rip->i_size >= MAX_FAST_SYMLINK_LENGTH) {
/* normal symlink */
if(!(bp = get_block_map(rip, 0))) {
r = EIO;
} else {
link_text = b_data(bp);
r = OK;
}
} else {
/* fast symlink, stored in inode */
link_text = (char*) rip->i_block;
r = OK;
}
if (r == OK) {
/* Passed all checks */
if (bytes > rip->i_size)
bytes = rip->i_size;
r = fsdriver_copyout(data, 0, link_text, bytes);
put_block(bp, DIRECTORY_BLOCK);
if (r == OK)
r = bytes;
}
put_inode(rip);
return(r);
}
