summaryrefslogtreecommitdiff
path: root/debian/patches/0005-isofs-use-a-seperate-lock-to-protect-node_cache.patch
diff options
context:
space:
mode:
Diffstat (limited to 'debian/patches/0005-isofs-use-a-seperate-lock-to-protect-node_cache.patch')
-rw-r--r--debian/patches/0005-isofs-use-a-seperate-lock-to-protect-node_cache.patch231
1 files changed, 0 insertions, 231 deletions
diff --git a/debian/patches/0005-isofs-use-a-seperate-lock-to-protect-node_cache.patch b/debian/patches/0005-isofs-use-a-seperate-lock-to-protect-node_cache.patch
deleted file mode 100644
index 0277ded1..00000000
--- a/debian/patches/0005-isofs-use-a-seperate-lock-to-protect-node_cache.patch
+++ /dev/null
@@ -1,231 +0,0 @@
-From b679f841d6214b3fb37587a6ca207bc1d9439a1e Mon Sep 17 00:00:00 2001
-From: Justus Winter <4winter@informatik.uni-hamburg.de>
-Date: Tue, 13 May 2014 15:16:31 +0200
-Subject: [PATCH 5/6] isofs: use a seperate lock to protect node_cache
-
-Previously, isofs used diskfs_node_refcnt_lock to serialize access to
-the node_cache.
-
-Use a separate lock to protect node_cache. Adjust the reference
-counting accordingly. Every node in the node_cache carries a light
-reference. When we are asked to give up that light reference, we
-reacquire our lock momentarily to check whether someone else
-reacquired a reference through the node_cache.
-
-* isofs/inode.c (nodecache_lock): New lock.
-(inode_cache_find): Use a separate lock to protect node_cache.
-Adjust the reference counting accordingly.
-(diskfs_cached_lookup): Likewise.
-(load_inode): Likewise.
-(cache_inode): Update comment accordingly.
-(diskfs_node_iterate): Likewise.
-(diskfs_node_norefs): Move the code removing the node from node_cache...
-(diskfs_try_dropping_softrefs): ... here, where we check whether
-someone reacquired a reference, and if so hold on to our light
-reference.
----
- isofs/inode.c | 83 +++++++++++++++++++++++++++++++++++++++++------------------
- 1 file changed, 58 insertions(+), 25 deletions(-)
-
-diff --git a/isofs/inode.c b/isofs/inode.c
-index cdc05ae..010d724 100644
---- a/isofs/inode.c
-+++ b/isofs/inode.c
-@@ -48,9 +48,19 @@ struct node_cache
- struct node *np; /* if live */
- };
-
-+/* The node_cache is a cache of nodes.
-+
-+ Access to node_cache, node_cache_size, and node_cache_alloced is
-+ protected by nodecache_lock.
-+
-+ Every node in the node_cache carries a light reference. When we
-+ are asked to give up that light reference, we reacquire our lock
-+ momentarily to check whether someone else reacquired a reference
-+ through the node_cache. */
- static int node_cache_size = 0;
- static int node_cache_alloced = 0;
- struct node_cache *node_cache = 0;
-+static pthread_rwlock_t nodecache_lock = PTHREAD_RWLOCK_INITIALIZER;
-
- /* Forward */
- static error_t read_disknode (struct node *,
-@@ -58,7 +68,7 @@ static error_t read_disknode (struct node *,
-
-
- /* See if node with identifier ID is in the cache. If so, return it,
-- with one additional reference. diskfs_node_refcnt_lock must be held
-+ with one additional reference. nodecache_lock must be held
- on entry to the call, and will be released iff the node was found
- in the cache. */
- void
-@@ -71,8 +81,8 @@ inode_cache_find (off_t id, struct node **npp)
- && node_cache[i].np)
- {
- *npp = node_cache[i].np;
-- (*npp)->references++;
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-+ diskfs_nref (*npp);
-+ pthread_rwlock_unlock (&nodecache_lock);
- pthread_mutex_lock (&(*npp)->lock);
- return;
- }
-@@ -92,7 +102,7 @@ use_file_start_id (struct dirrect *record, struct rrip_lookup *rr)
- }
-
- /* Enter NP into the cache. The directory entry we used is DR, the
-- cached Rock-Ridge info RR. diskfs_node_refcnt_lock must be held. */
-+ cached Rock-Ridge info RR. nodecache_lock must be held. */
- void
- cache_inode (struct node *np, struct dirrect *record,
- struct rrip_lookup *rr)
-@@ -155,7 +165,7 @@ diskfs_cached_lookup (ino_t id, struct node **npp)
- to avoid presenting zero cache ID's. */
- id--;
-
-- pthread_spin_lock (&diskfs_node_refcnt_lock);
-+ pthread_rwlock_rdlock (&nodecache_lock);
- assert (id < node_cache_size);
-
- np = node_cache[id].np;
-@@ -174,7 +184,7 @@ diskfs_cached_lookup (ino_t id, struct node **npp)
- dn = malloc (sizeof (struct disknode));
- if (!dn)
- {
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-+ pthread_rwlock_unlock (&nodecache_lock);
- release_rrip (&rr);
- return ENOMEM;
- }
-@@ -185,16 +195,17 @@ diskfs_cached_lookup (ino_t id, struct node **npp)
- if (!np)
- {
- free (dn);
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-+ pthread_rwlock_unlock (&nodecache_lock);
- release_rrip (&rr);
- return ENOMEM;
- }
- np->cache_id = id + 1; /* see above for rationale for increment */
- pthread_mutex_lock (&np->lock);
- c->np = np;
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-+ diskfs_nref_light (np);
-+ pthread_rwlock_unlock (&nodecache_lock);
-
-- err = read_disknode (np, node_cache[id].dr, &rr);
-+ err = read_disknode (np, dn->dr, &rr);
- if (!err)
- *npp = np;
-
-@@ -204,8 +215,8 @@ diskfs_cached_lookup (ino_t id, struct node **npp)
- }
-
-
-- np->references++;
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-+ diskfs_nref (np);
-+ pthread_rwlock_unlock (&nodecache_lock);
- pthread_mutex_lock (&np->lock);
- *npp = np;
- return 0;
-@@ -315,7 +326,7 @@ load_inode (struct node **npp, struct dirrect *record,
- if (rr->valid & VALID_CL)
- record = rr->realdirent;
-
-- pthread_spin_lock (&diskfs_node_refcnt_lock);
-+ pthread_rwlock_rdlock (&nodecache_lock);
-
- /* First check the cache */
- if (use_file_start_id (record, rr))
-@@ -323,19 +334,16 @@ load_inode (struct node **npp, struct dirrect *record,
- else
- inode_cache_find ((off_t) ((void *) record - (void *) disk_image), npp);
-
-+ pthread_rwlock_unlock (&nodecache_lock);
-+
- if (*npp)
-- {
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-- return 0;
-- }
-+ return 0;
-
- /* Create a new node */
- dn = malloc (sizeof (struct disknode));
- if (!dn)
-- {
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-- return ENOMEM;
-- }
-+ return ENOMEM;
-+
- dn->fileinfo = 0;
- dn->dr = record;
- dn->file_start = file_start;
-@@ -344,14 +352,14 @@ load_inode (struct node **npp, struct dirrect *record,
- if (!np)
- {
- free (dn);
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
- return ENOMEM;
- }
-
- pthread_mutex_lock (&np->lock);
-
-+ pthread_rwlock_wrlock (&nodecache_lock);
- cache_inode (np, record, rr);
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-+ pthread_rwlock_unlock (&nodecache_lock);
-
- err = read_disknode (np, record, rr);
- *npp = np;
-@@ -505,9 +513,6 @@ error_t (*diskfs_read_symlink_hook) (struct node *, char *)
- void
- diskfs_node_norefs (struct node *np)
- {
-- assert (node_cache[np->cache_id - 1].np == np);
-- node_cache[np->cache_id - 1].np = 0;
--
- if (np->dn->translator)
- free (np->dn->translator);
-
-@@ -521,6 +526,34 @@ diskfs_node_norefs (struct node *np)
- void
- diskfs_try_dropping_softrefs (struct node *np)
- {
-+ pthread_rwlock_wrlock (&nodecache_lock);
-+ if (np->cache_id != 0)
-+ {
-+ assert (node_cache[np->cache_id - 1].np == np);
-+
-+ /* Check if someone reacquired a reference through the
-+ node_cache. */
-+ 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)
-+ {
-+ /* A reference was reacquired through a hash table lookup.
-+ It's fine, we didn't touch anything yet. */
-+ pthread_rwlock_unlock (&nodecache_lock);
-+ return;
-+ }
-+
-+ node_cache[np->cache_id - 1].np = 0;
-+ np->cache_id = 0;
-+ diskfs_nrele_light (np);
-+ }
-+ pthread_rwlock_unlock (&nodecache_lock);
-+
- drop_pager_softrefs (np);
- }
-
---
-2.0.0.rc2
-
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-17 22:24:08 +0000