xv6/buf.h

struct buf {
  int flags;
  uint dev;
  uint sector;
  struct spinlock lock;
  struct sleeplock sleeplock;
  struct buf *prev; // LRU cache list
  struct buf *next;
  struct buf *qnext; // disk queue
  uchar data[512];
};
#define B_VALID 0x1  // buffer has been read from disk
#define B_DIRTY 0x2  // buffer needs to be written to disk
bread iget mkfs makes a file system image put this in your .bochsrc: ata0-slave: type=disk, mode=flat, path="fs.img", cylinders=1024, heads=1, spt=1 2006-07-21 13:18:04 +00:00			`struct buf {`
			`int flags;`
fix getblk to actually lock the block no more cons_put system calls usertests tests two processes writing files 2006-08-12 11:38:57 +00:00			`uint dev;`
			`uint sector;`
Introduce and use sleeplocks instead of BUSY flags Remove I_BUSY, B_BUSY, and intrans defs and usages One spinlock per buf to avoid ugly loop in bget fix race in filewrite (don't update f->off after releasing lock) 2011-08-26 14:08:29 +00:00			`struct spinlock lock;`
			`struct sleeplock sleeplock;`
simplify ide queuing nits in comments 2007-08-24 19:32:36 +00:00			`struct buf *prev; // LRU cache list`
LRU disk cache replacement 2006-08-12 22:34:13 +00:00			`struct buf *next;`
simplify ide queuing nits in comments 2007-08-24 19:32:36 +00:00			`struct buf *qnext; // disk queue`
bread iget mkfs makes a file system image put this in your .bochsrc: ata0-slave: type=disk, mode=flat, path="fs.img", cylinders=1024, heads=1, spt=1 2006-07-21 13:18:04 +00:00			`uchar data[512];`
			`};`
Introduce and use sleeplocks instead of BUSY flags Remove I_BUSY, B_BUSY, and intrans defs and usages One spinlock per buf to avoid ugly loop in bget fix race in filewrite (don't update f->off after releasing lock) 2011-08-26 14:08:29 +00:00			`#define B_VALID 0x1 // buffer has been read from disk`
			`#define B_DIRTY 0x2 // buffer needs to be written to disk`
Another attempt at the bio.c comment. Rename B_WRITE to B_DIRTY and then let ide.c maintain the B_VALID and B_DIRTY flags. 2007-08-27 14:09:30 +00:00