diff options
author | Justus Winter <4winter@informatik.uni-hamburg.de> | 2014-06-03 09:41:29 +0200 |
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committer | Justus Winter <4winter@informatik.uni-hamburg.de> | 2014-06-03 09:41:29 +0200 |
commit | 0249914b50e228c713464729ffe1463732c9fbda (patch) | |
tree | 006e1651d56eb73e7e55c910413819b87e4b238d /debian/patches/0005-isofs-use-a-seperate-lock-to-protect-node_cache.patch | |
parent | 12837f5988fc0fcd332a98487aeb73e74fc407ae (diff) |
drop old patch series
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.patch | 231 |
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 - |