summaryrefslogtreecommitdiff
path: root/fatfs
diff options
context:
space:
mode:
authorJustus Winter <4winter@informatik.uni-hamburg.de>2014-05-14 11:19:35 +0200
committerJustus Winter <4winter@informatik.uni-hamburg.de>2015-04-17 14:06:46 +0200
commitc16eed2cb64089bf7d958db0fe85352f4ceefb4d (patch)
tree3240f6e025fa4c4fb47d7d270f285a7f0f9612e4 /fatfs
parent8c050fb080c6e1981dc8e5a97a2313cd24e9b4b4 (diff)
libdiskfs: lock-less reference counting of nodes
* libdiskfs/diskfs.h (struct node): Use refcounts_t for reference counting. (diskfs_node_refcnt_lock): Remove. (diskfs_node_norefs,diskfs_drop_node): Change comments accordingly. * libdiskfs/init-init.c: Adjust accordingly. * libdiskfs/node-drop.c: Likewise. * libdiskfs/node-make.c: Likewise. * libdiskfs/node-nput.c: Likewise. * libdiskfs/node-nputl.c: Likewise. * libdiskfs/node-nref.c: Likewise. * libdiskfs/node-nrefl.c: Likewise. * libdiskfs/node-nrele.c: Likewise. * libdiskfs/node-nrelel.c: Likewise. * ext2fs/inode.c: Likewise. * fatfs/inode.c: Likewise. * isofs/inode.c: Likewise. * tmpfs/node.c: Likewise. * doc/hurd.texi: Likewise.
Diffstat (limited to 'fatfs')
-rw-r--r--fatfs/inode.c27
1 files changed, 8 insertions, 19 deletions
diff --git a/fatfs/inode.c b/fatfs/inode.c
index 1d670f53..f228618d 100644
--- a/fatfs/inode.c
+++ b/fatfs/inode.c
@@ -55,7 +55,6 @@
through the nodehash. */
static struct node *nodehash[INOHSZ];
static size_t nodehash_nr_items;
-/* nodecache_lock must be acquired before diskfs_node_refcnt_lock. */
static pthread_rwlock_t nodecache_lock = PTHREAD_RWLOCK_INITIALIZER;
static error_t read_node (struct node *np, vm_address_t buf);
@@ -254,14 +253,8 @@ diskfs_node_norefs (struct node *np)
if (np->dn->translator)
free (np->dn->translator);
- /* It is safe to unlock diskfs_node_refcnt_lock here for a while because
- all references to the node have been deleted. */
if (np->dn->dirnode)
- {
- pthread_spin_unlock (&diskfs_node_refcnt_lock);
- diskfs_nrele (np->dn->dirnode);
- pthread_spin_lock (&diskfs_node_refcnt_lock);
- }
+ diskfs_nrele (np->dn->dirnode);
assert (!np->dn->pager);
@@ -279,14 +272,10 @@ diskfs_try_dropping_softrefs (struct node *np)
{
/* Check if someone reacquired a reference through the
nodehash. */
- unsigned int references;
- pthread_spin_lock (&diskfs_node_refcnt_lock);
- references = np->references;
- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-
- /* An additional reference is acquired by libdiskfs across calls
- to diskfs_try_dropping_softrefs. */
- if (references > 1)
+ struct references result;
+ refcounts_references (&np->refcounts, &result);
+
+ if (result.hard > 0)
{
/* A reference was reacquired through a hash table lookup.
It's fine, we didn't touch anything yet. */
@@ -392,7 +381,7 @@ read_node (struct node *np, vm_address_t buf)
/* Files in fatfs depend on the directory that hold the file. */
np->dn->dirnode = dp;
if (dp)
- dp->references++;
+ refcounts_ref (&dp->refcounts, NULL);
pthread_rwlock_rdlock (&np->dn->dirent_lock);
@@ -627,7 +616,7 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
/* We acquire a hard reference for node, but without using
diskfs_nref. We do this so that diskfs_new_hardrefs will not
get called. */
- node->references++;
+ refcounts_ref (&node->refcounts, NULL);
}
pthread_rwlock_unlock (&nodecache_lock);
@@ -838,7 +827,7 @@ diskfs_alloc_node (struct node *dir, mode_t mode, struct node **node)
/* FIXME: We know that readnode couldn't put this in. */
np->dn->dirnode = dir;
- dir->references++;
+ refcounts_ref (&dir->refcounts, NULL);
*node = np;
return 0;