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a little more lock documentation

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This commit is contained in:
Robert Morris 2017-08-08 14:12:25 -04:00
parent 70d912b332
commit 1c7aa96005
1 changed files with 13 additions and 0 deletions
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13
fs.c
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@ -154,6 +154,15 @@ bfree(int dev, uint b)
// Many internal file system functions expect the caller to
// have locked the inodes involved; this lets callers create
// multi-step atomic operations.
//
// The icache.lock spin-lock defends ip->ref, ip->dev, and ip->inum.
// Since ip->ref indicates whether an icache entry is free, the
// icache.lock defends icache allocation. icache.lock also defends
// all fields of an unallocated icache entry, during allocation.
//
// An ip->lock sleep-lock defends all ip-> fields other than ref,
// dev, and inum. One must hold ip->lock in order to
// read or write that inode's ip->valid, ip->size, ip->type, &c.
struct {
struct spinlock lock;
@ -205,6 +214,7 @@ ialloc(uint dev, short type)
}
// Copy a modified in-memory inode to disk.
// Caller must hold ip->lock.
void
iupdate(struct inode *ip)
{
@ -421,6 +431,7 @@ itrunc(struct inode *ip)
}
// Copy stat information from inode.
// Caller must hold ip->lock.
void
stati(struct inode *ip, struct stat *st)
{
@ -433,6 +444,7 @@ stati(struct inode *ip, struct stat *st)
//PAGEBREAK!
// Read data from inode.
// Caller must hold ip->lock.
int
readi(struct inode *ip, char *dst, uint off, uint n)
{
@ -461,6 +473,7 @@ readi(struct inode *ip, char *dst, uint off, uint n)
// PAGEBREAK!
// Write data to inode.
// Caller must hold ip->lock.
int
writei(struct inode *ip, char *src, uint off, uint n)
{