sanchayanmaity/xv6-cs450
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Compare commits

base: sanchayanmaity:inc-max-file-size
Branches Tags
sanchayanmaity:master
sanchayanmaity:inc-max-file-size
sanchayanmaity:add_sys_call_getcount
..
compare: sanchayanmaity:master
Branches Tags
sanchayanmaity:inc-max-file-size
sanchayanmaity:add_sys_call_getcount
sanchayanmaity:master

No commits in common. "inc-max-file-size" and "master" have entirely different histories.
inc-max-fi ... master

3 changed files with 6 additions and 46 deletions
Show stats Expand all files Collapse all files

2
file.h
View file

@ -21,7 +21,7 @@ struct inode {
short minor; short minor;
short nlink; short nlink;
uint size; uint size;
uint addrs[NDIRECT+3]; uint addrs[NDIRECT+1];
}; };
#define I_BUSY 0x1 #define I_BUSY 0x1
#define I_VALID 0x2 #define I_VALID 0x2

42
fs.c
View file

@ -356,25 +356,18 @@ iunlockput(struct inode *ip)
static uint static uint
bmap(struct inode *ip, uint bn) bmap(struct inode *ip, uint bn)
{ {
uint addr, *a, i; uint addr, *a;
struct buf *bp; struct buf *bp;
// We use 10 direct, two indirect and one double indirect pointer
if(bn < NDIRECT){ if(bn < NDIRECT){
// If block number is less than direct pointers available
// allocate a disk block if not allocated/available
// then return the address of the block
if((addr = ip->addrs[bn]) == 0) if((addr = ip->addrs[bn]) == 0)
ip->addrs[bn] = addr = balloc(ip->dev); ip->addrs[bn] = addr = balloc(ip->dev);
return addr; return addr;
} }
// The block number does not fall in the first 10 direct blocks
// Substract the number from the passed block number
bn -= NDIRECT; bn -= NDIRECT;
if(bn < NINDIRECT){ if(bn < NINDIRECT){
// Load indirect block, allocating if necessary. // Load indirect block, allocating if necessary.
// This is the first indirect block range
if((addr = ip->addrs[NDIRECT]) == 0) if((addr = ip->addrs[NDIRECT]) == 0)
ip->addrs[NDIRECT] = addr = balloc(ip->dev); ip->addrs[NDIRECT] = addr = balloc(ip->dev);
bp = bread(ip->dev, addr); bp = bread(ip->dev, addr);
@ -385,39 +378,6 @@ bmap(struct inode *ip, uint bn)
} }
brelse(bp); brelse(bp);
return addr; return addr;
} else if(bn < NINDIRECT * 2){
bn -= NINDIRECT;
// Load indirect block, allocating if necessary.
// This is the second indirect block range
if((addr = ip->addrs[NDIRECT+1]) == 0)
ip->addrs[NDIRECT+1] = addr = balloc(ip->dev);
bp = bread(ip->dev, addr);
a = (uint*)bp->data;
if((addr = a[bn]) == 0){
a[bn] = addr = balloc(ip->dev);
log_write(bp);
}
brelse(bp);
return addr;
} else {
// We are now in the double indirect block range
bn -= NINDIRECT * 2;
// Load indirect block, allocating if necessary.
if((addr = ip->addrs[NDIRECT+2]) == 0)
ip->addrs[NDIRECT+2] = addr = balloc(ip->dev);
bp = bread(ip->dev, addr);
a = (uint*)bp->data;
// This last double indirect block should contain addresses to
// other blocks and not data. Fig 6.4 of xv6 booklet
for (i = 0; i < BSIZE/4; i++){
if((addr = a[i]) == 0){
a[bn] = addr = balloc(ip->dev);
log_write(bp);
break;
}
}
brelse(bp);
return addr;
} }
panic("bmap: out of range"); panic("bmap: out of range");

6
fs.h
View file

@ -19,9 +19,9 @@ struct superblock {
uint nlog; // Number of log blocks uint nlog; // Number of log blocks
}; };
#define NDIRECT 10 #define NDIRECT 12
#define NINDIRECT (BSIZE / sizeof(uint)) #define NINDIRECT (BSIZE / sizeof(uint))
#define MAXFILE (NDIRECT + 2 * NINDIRECT + NINDIRECT * NINDIRECT) #define MAXFILE (NDIRECT + NINDIRECT)
// On-disk inode structure // On-disk inode structure
struct dinode { struct dinode {
@ -30,7 +30,7 @@ struct dinode {
short minor; // Minor device number (T_DEV only) short minor; // Minor device number (T_DEV only)
short nlink; // Number of links to inode in file system short nlink; // Number of links to inode in file system
uint size; // Size of file (bytes) uint size; // Size of file (bytes)
uint addrs[NDIRECT+3]; // Data block addresses uint addrs[NDIRECT+1]; // Data block addresses
}; };
// Inodes per block. // Inodes per block.