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-rw-r--r--fs.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/fs.c b/fs.c
index c73c530..67616a4 100644
--- a/fs.c
+++ b/fs.c
@@ -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)
{