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-rw-r--r--debian/patches/0004-fatfs-use-a-seperate-lock-to-protect-nodehash.patch250
1 files changed, 0 insertions, 250 deletions
diff --git a/debian/patches/0004-fatfs-use-a-seperate-lock-to-protect-nodehash.patch b/debian/patches/0004-fatfs-use-a-seperate-lock-to-protect-nodehash.patch
deleted file mode 100644
index c469bf08..00000000
--- a/debian/patches/0004-fatfs-use-a-seperate-lock-to-protect-nodehash.patch
+++ /dev/null
@@ -1,250 +0,0 @@
-From 11e20c7ddaaead446b944f0b3475016386eaaf13 Mon Sep 17 00:00:00 2001
-From: Justus Winter <4winter@informatik.uni-hamburg.de>
-Date: Tue, 13 May 2014 15:14:53 +0200
-Subject: [PATCH 4/9] fatfs: use a seperate lock to protect nodehash
-
-Previously, fatfs used diskfs_node_refcnt_lock to serialize access to
-the nodehash.
-
-Use a separate lock to protect nodehash. Adjust the reference
-counting accordingly. Every node in the nodehash 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 nodehash.
-
-* fatfs/inode.c (nodecache_lock): New lock.
-(diskfs_cached_lookup): Use a separate lock to protect nodehash.
-Adjust the reference counting accordingly.
-(ifind): Likewise.
-(diskfs_node_iterate): Likewise.
-(diskfs_node_norefs): Move the code removing the node from nodehash...
-(diskfs_try_dropping_softrefs): ... here, where we check whether
-someone reacquired a reference, and if so hold on to our light
-reference.
----
- fatfs/inode.c | 97 +++++++++++++++++++++++++++++++++++++++++------------------
- 1 file changed, 67 insertions(+), 30 deletions(-)
-
-diff --git a/fatfs/inode.c b/fatfs/inode.c
-index ed6f3f0..352c7a3 100644
---- a/fatfs/inode.c
-+++ b/fatfs/inode.c
-@@ -44,8 +44,18 @@
- #define INOHASH(ino) (((unsigned)(ino))%INOHSZ)
- #endif
-
-+/* The nodehash is a cache of nodes.
-+
-+ Access to nodehash and nodehash_nr_items is protected by
-+ nodecache_lock.
-+
-+ Every node in the nodehash 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 nodehash. */
- static struct node *nodehash[INOHSZ];
- static size_t nodehash_nr_items;
-+static pthread_rwlock_t nodecache_lock = PTHREAD_RWLOCK_INITIALIZER;
-
- static error_t read_node (struct node *np, vm_address_t buf);
-
-@@ -67,24 +77,23 @@ diskfs_cached_lookup (ino64_t inum, struct node **npp)
- struct node *np;
- struct disknode *dn;
-
-- pthread_spin_lock (&diskfs_node_refcnt_lock);
-+ pthread_rwlock_rdlock (&nodecache_lock);
- for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext)
- if (np->cache_id == inum)
- {
-- 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;
- }
-+ pthread_rwlock_unlock (&nodecache_lock);
-
- /* Format specific data for the new node. */
- dn = malloc (sizeof (struct disknode));
- if (! dn)
-- {
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-- return ENOMEM;
-- }
-+ return ENOMEM;
-+
- dn->pager = 0;
- dn->first = 0;
- dn->last = 0;
-@@ -102,15 +111,16 @@ diskfs_cached_lookup (ino64_t inum, struct node **npp)
- pthread_mutex_lock (&np->lock);
-
- /* Put NP in NODEHASH. */
-+ pthread_rwlock_wrlock (&nodecache_lock);
- dn->hnext = nodehash[INOHASH(inum)];
- if (dn->hnext)
- dn->hnext->dn->hprevp = &dn->hnext;
- dn->hprevp = &nodehash[INOHASH(inum)];
- nodehash[INOHASH(inum)] = np;
-+ diskfs_nref_light (np);
- nodehash_nr_items += 1;
-+ pthread_rwlock_unlock (&nodecache_lock);
-
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
--
- /* Get the contents of NP off disk. */
- err = read_node (np, 0);
-
-@@ -133,24 +143,23 @@ diskfs_cached_lookup_in_dirbuf (int inum, struct node **npp, vm_address_t buf)
- struct node *np;
- struct disknode *dn;
-
-- pthread_spin_lock (&diskfs_node_refcnt_lock);
-+ pthread_rwlock_rdlock (&nodecache_lock);
- for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext)
- if (np->cache_id == inum)
- {
-- 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;
- }
-+ pthread_rwlock_unlock (&nodecache_lock);
-
- /* Format specific data for the new node. */
- dn = malloc (sizeof (struct disknode));
- if (! dn)
-- {
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-- return ENOMEM;
-- }
-+ return ENOMEM;
-+
- dn->pager = 0;
- dn->first = 0;
- dn->last = 0;
-@@ -168,15 +177,16 @@ diskfs_cached_lookup_in_dirbuf (int inum, struct node **npp, vm_address_t buf)
- pthread_mutex_lock (&np->lock);
-
- /* Put NP in NODEHASH. */
-+ pthread_rwlock_wrlock (&nodecache_lock);
- dn->hnext = nodehash[INOHASH(inum)];
- if (dn->hnext)
- dn->hnext->dn->hprevp = &dn->hnext;
- dn->hprevp = &nodehash[INOHASH(inum)];
- nodehash[INOHASH(inum)] = np;
-+ diskfs_nref_light (np);
- nodehash_nr_items += 1;
-+ pthread_rwlock_unlock (&nodecache_lock);
-
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
--
- /* Get the contents of NP off disk. */
- err = read_node (np, buf);
-
-@@ -196,14 +206,13 @@ ifind (ino_t inum)
- {
- struct node *np;
-
-- pthread_spin_lock (&diskfs_node_refcnt_lock);
-+ pthread_rwlock_rdlock (&nodecache_lock);
- for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext)
- {
- if (np->cache_id != inum)
- continue;
-
-- assert (np->references);
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-+ pthread_rwlock_unlock (&nodecache_lock);
- return np;
- }
- assert (0);
-@@ -216,11 +225,6 @@ diskfs_node_norefs (struct node *np)
- {
- struct cluster_chain *last = np->dn->first;
-
-- *np->dn->hprevp = np->dn->hnext;
-- if (np->dn->hnext)
-- np->dn->hnext->dn->hprevp = np->dn->hprevp;
-- nodehash_nr_items -= 1;
--
- while (last)
- {
- struct cluster_chain *next = last->next;
-@@ -251,6 +255,35 @@ diskfs_node_norefs (struct node *np)
- void
- diskfs_try_dropping_softrefs (struct node *np)
- {
-+ pthread_rwlock_wrlock (&nodecache_lock);
-+ if (np->dn->hnext != NULL)
-+ {
-+ /* 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)
-+ {
-+ /* A reference was reacquired through a hash table lookup.
-+ It's fine, we didn't touch anything yet. */
-+ pthread_rwlock_unlock (&nodecache_lock);
-+ return;
-+ }
-+
-+ *np->dn->hprevp = np->dn->hnext;
-+ if (np->dn->hnext)
-+ np->dn->hnext->dn->hprevp = np->dn->hprevp;
-+ np->dn->hnext = NULL;
-+ nodehash_nr_items -= 1;
-+ diskfs_nrele_light (np);
-+ }
-+ pthread_rwlock_unlock (&nodecache_lock);
-+
- drop_pager_softrefs (np);
- }
-
-@@ -554,12 +587,12 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
- size_t num_nodes;
- struct node *node, **node_list, **p;
-
-- pthread_spin_lock (&diskfs_node_refcnt_lock);
-+ pthread_rwlock_rdlock (&nodecache_lock);
-
- /* We must copy everything from the hash table into another data structure
- to avoid running into any problems with the hash-table being modified
- during processing (normally we delegate access to hash-table with
-- diskfs_node_refcnt_lock, but we can't hold this while locking the
-+ nodecache_lock, but we can't hold this while locking the
- individual node locks). */
-
- num_nodes = nodehash_nr_items;
-@@ -570,10 +603,14 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
- for (node = nodehash[n]; node; node = node->dn->hnext)
- {
- *p++ = node;
-- node->references++;
-+
-+ /* 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++;
- }
-
-- pthread_spin_unlock (&diskfs_node_refcnt_lock);
-+ pthread_rwlock_unlock (&nodecache_lock);
-
- p = node_list;
- while (num_nodes-- > 0)
---
-2.0.0.rc2
-
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-17 22:35:39 +0000