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-rw-r--r--debian/patches/0003-isofs-use-a-seperate-lock-to-protect-node_cache.patch310
1 files changed, 0 insertions, 310 deletions
diff --git a/debian/patches/0003-isofs-use-a-seperate-lock-to-protect-node_cache.patch b/debian/patches/0003-isofs-use-a-seperate-lock-to-protect-node_cache.patch
deleted file mode 100644
index cd7811b8..00000000
--- a/debian/patches/0003-isofs-use-a-seperate-lock-to-protect-node_cache.patch
+++ /dev/null
@@ -1,310 +0,0 @@
-From 580ddc597aa7bda6f4941e308482fedd862a43c9 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 3/4] 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 | 146 +++++++++++++++++++++++++++++++++++++++++-----------------
- 1 file changed, 105 insertions(+), 41 deletions(-)
-
-diff --git a/isofs/inode.c b/isofs/inode.c
-index cdc05ae..3941580 100644
---- a/isofs/inode.c
-+++ b/isofs/inode.c
-@@ -48,35 +48,53 @@ 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;
-+/* nodecache_lock must be acquired before diskfs_node_refcnt_lock. */
-+static pthread_rwlock_t nodecache_lock = PTHREAD_RWLOCK_INITIALIZER;
-
- /* Forward */
- static error_t read_disknode (struct node *,
- struct dirrect *, struct rrip_lookup *);
-
-
-+/* Lookup node with id ID. Returns NULL if the node is not found in
-+ the node cache. */
-+static struct node *
-+lookup (off_t id)
-+{
-+ int i;
-+ for (i = 0; i < node_cache_size; i++)
-+ if (node_cache[i].id == id
-+ && node_cache[i].np)
-+ return node_cache[i].np;
-+ return NULL;
-+}
-+
- /* 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
- inode_cache_find (off_t id, struct node **npp)
- {
-- int i;
--
-- for (i = 0; i < node_cache_size; i++)
-- if (node_cache[i].id == id
-- && node_cache[i].np)
-- {
-- *npp = node_cache[i].np;
-- (*npp)->references++;
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-- pthread_mutex_lock (&(*npp)->lock);
-- return;
-- }
-- *npp = 0;
-+ *npp = lookup (id);
-+ if (*npp)
-+ {
-+ diskfs_nref (*npp);
-+ pthread_rwlock_unlock (&nodecache_lock);
-+ pthread_mutex_lock (&(*npp)->lock);
-+ }
- }
-
-
-@@ -92,7 +110,7 @@ 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)
-@@ -137,6 +155,7 @@ cache_inode (struct node *np, struct dirrect *record,
- c->id = id;
- c->dr = record;
- c->file_start = np->dn->file_start;
-+ diskfs_nref_light (np);
- c->np = np;
-
- /* PLUS 1 so that we don't store zero cache ID's (not allowed by diskfs) */
-@@ -155,7 +174,7 @@ 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;
-@@ -166,6 +185,8 @@ diskfs_cached_lookup (ino_t id, struct node **npp)
- struct rrip_lookup rr;
- struct disknode *dn;
-
-+ pthread_rwlock_unlock (&nodecache_lock);
-+
- rrip_lookup (node_cache[id].dr, &rr, 1);
-
- /* We should never cache the wrong directory entry */
-@@ -174,7 +195,7 @@ 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 +206,26 @@ 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);
-+
-+ pthread_rwlock_wrlock (&nodecache_lock);
-+ if (c->np != NULL)
-+ {
-+ /* We lost a race. */
-+ diskfs_nput (np);
-+ np = c->np;
-+ goto gotit;
-+ }
- 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;
-
-@@ -203,9 +234,9 @@ diskfs_cached_lookup (ino_t id, struct node **npp)
- return err;
- }
-
--
-- np->references++;
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-+ gotit:
-+ diskfs_nref (np);
-+ pthread_rwlock_unlock (&nodecache_lock);
- pthread_mutex_lock (&np->lock);
- *npp = np;
- return 0;
-@@ -307,7 +338,8 @@ load_inode (struct node **npp, struct dirrect *record,
- error_t err;
- off_t file_start;
- struct disknode *dn;
-- struct node *np;
-+ struct node *np, *tmp;
-+ off_t id;
-
- err = calculate_file_start (record, &file_start, rr);
- if (err)
-@@ -315,27 +347,23 @@ load_inode (struct node **npp, struct dirrect *record,
- if (rr->valid & VALID_CL)
- record = rr->realdirent;
-
-- pthread_spin_lock (&diskfs_node_refcnt_lock);
--
- /* First check the cache */
- if (use_file_start_id (record, rr))
-- inode_cache_find (file_start << store->log2_block_size, npp);
-+ id = file_start << store->log2_block_size;
- else
-- inode_cache_find ((off_t) ((void *) record - (void *) disk_image), npp);
-+ id = (off_t) ((void *) record - (void *) disk_image);
-
-+ pthread_rwlock_rdlock (&nodecache_lock);
-+ inode_cache_find (id, npp);
- if (*npp)
-- {
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-- return 0;
-- }
-+ return 0;
-+ pthread_rwlock_unlock (&nodecache_lock);
-
- /* 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 +372,25 @@ 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);
-+ tmp = lookup (id);
-+ if (tmp)
-+ {
-+ /* We lost a race. */
-+ diskfs_nput (np);
-+ diskfs_nref (tmp);
-+ *npp = tmp;
-+ pthread_rwlock_unlock (&nodecache_lock);
-+ return 0;
-+ }
-+
- 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 +544,6 @@ 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 +557,34 @@ 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
-
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