From b497f1613187c142ad6d0b76761a49811c37da80 Mon Sep 17 00:00:00 2001 From: Justus Winter <4winter@informatik.uni-hamburg.de> Date: Thu, 16 Apr 2015 16:12:05 +0200 Subject: fatfs: port to libdiskfs' node cache * fatfs/inode.c: Drop all cache-related code. (diskfs_user_make_node): New function. (diskfs_cached_lookup_in_dirbuf): Reimplement using the `lookup_context'. (read_node): Rename to diskfs_user_read_node and adopt accordingly. (diskfs_try_dropping_softrefs): Rename to `diskfs_user_try_dropping_softrefs'. (diskfs_node_reload): Pass context to `diskfs_user_read_node'. (diskfs_alloc_node): Pass `dir' via context to `diskfs_user_read_node'. * fatfs/fatfs.h (struct disknode): Drop fields `hnext', `hprevp'. (struct lookup_context): New definition. (ifind): Drop declaration. * fatfs/dir.c (diskfs_lookup_hard): Adjust accordingly. * fatfs/main.c (fetch_root): Likewise. --- fatfs/dir.c | 6 +- fatfs/fatfs.h | 17 +++- fatfs/inode.c | 292 ++++++---------------------------------------------------- fatfs/main.c | 6 +- 4 files changed, 46 insertions(+), 275 deletions(-) (limited to 'fatfs') diff --git a/fatfs/dir.c b/fatfs/dir.c index 5a38c63a..9eea74c1 100644 --- a/fatfs/dir.c +++ b/fatfs/dir.c @@ -342,7 +342,7 @@ diskfs_lookup_hard (struct node *dp, const char *name, enum lookup_type type, /* Here below are the spec dotdot cases. */ else if (type == RENAME || type == REMOVE) - np = ifind (inum); + np = diskfs_cached_ifind (inum); else if (type == LOOKUP) { @@ -395,7 +395,7 @@ diskfs_lookup_hard (struct node *dp, const char *name, enum lookup_type type, diskfs_nput (np); } else if (type == RENAME || type == REMOVE) - /* We just did ifind to get np; that allocates + /* We just did diskfs_cached_ifind to get np; that allocates no new references, so we don't have anything to do. */ ; else if (type == LOOKUP) @@ -732,7 +732,7 @@ diskfs_dirrewrite_hard (struct node *dp, struct node *np, struct dirstat *ds) assert (err != EINVAL); /* Lookup the node, we already have a reference. */ - oldnp = ifind (inode); + oldnp = diskfs_cached_ifind (inode); assert (ds->type == RENAME); assert (ds->stat == HERE_TIS); diff --git a/fatfs/fatfs.h b/fatfs/fatfs.h index 9d385463..3c3d8366 100644 --- a/fatfs/fatfs.h +++ b/fatfs/fatfs.h @@ -36,9 +36,6 @@ struct disknode { cluster_t start_cluster; - /* Links on hash list. */ - struct node *hnext, **hprevp; - /* The inode as returned by virtual inode management routines. */ inode_t inode; @@ -71,6 +68,18 @@ struct disknode int dir_idx; }; +struct lookup_context +{ + /* The inode as returned by virtual inode management routines. */ + inode_t inode; + + /* Use BUF as the directory file map. */ + vm_address_t buf; + + /* Directory this node was allocated in (used by diskfs_alloc_node). */ + struct node *dir; +}; + struct user_pager_info { struct node *node; @@ -117,8 +126,6 @@ void flush_node_pager (struct node *node); void write_all_disknodes (); -struct node *ifind (ino_t inum); - error_t fat_get_next_cluster (cluster_t cluster, cluster_t *next_cluster); void fat_to_unix_filename (const char *, char *); diff --git a/fatfs/inode.c b/fatfs/inode.c index f228618d..610f3575 100644 --- a/fatfs/inode.c +++ b/fatfs/inode.c @@ -37,69 +37,21 @@ #define UF_IMMUTABLE 0 #endif -#define INOHSZ 512 -#if ((INOHSZ&(INOHSZ-1)) == 0) -#define INOHASH(ino) ((ino)&(INOHSZ-1)) -#else -#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); - -/* Initialize the inode hash table. */ -void -inode_init () -{ - int n; - for (n = 0; n < INOHSZ; n++) - nodehash[n] = 0; -} - -/* Lookup node with inode number INUM. Returns NULL if the node is - not found in the node cache. */ -static struct node * -lookup (ino_t inum) -{ - struct node *np; - for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext) - if (np->cache_id == inum) - return np; - return NULL; -} - -/* Fetch inode INUM, set *NPP to the node structure; gain one user - reference and lock the node. */ +/* The user must define this function if she wants to use the node + cache. Create and initialize a node. */ error_t -diskfs_cached_lookup (ino64_t inum, struct node **npp) +diskfs_user_make_node (struct node **npp, struct lookup_context *ctx) { - error_t err; - struct node *np, *tmp; + struct node *np; struct disknode *dn; - pthread_rwlock_rdlock (&nodecache_lock); - np = lookup (inum); - if (np) - goto gotit; - pthread_rwlock_unlock (&nodecache_lock); - - /* Format specific data for the new node. */ - dn = malloc (sizeof (struct disknode)); - if (! dn) + /* Create the new node. */ + np = diskfs_make_node_alloc (sizeof *dn); + if (np == NULL) return ENOMEM; + /* Format specific data for the new node. */ + dn = np->dn; dn->pager = 0; dn->first = 0; dn->last = 0; @@ -108,49 +60,9 @@ diskfs_cached_lookup (ino64_t inum, struct node **npp) dn->chain_extension_lock = PTHREAD_SPINLOCK_INITIALIZER; pthread_rwlock_init (&dn->alloc_lock, NULL); pthread_rwlock_init (&dn->dirent_lock, NULL); - - /* Create the new node. */ - np = diskfs_make_node (dn); - np->cache_id = inum; - np->dn->inode = vi_lookup(inum); - pthread_mutex_lock (&np->lock); - - /* Put NP in NODEHASH. */ - pthread_rwlock_wrlock (&nodecache_lock); - tmp = lookup (inum); - if (tmp) - { - /* We lost a race. */ - diskfs_nput (np); - np = tmp; - goto gotit; - } - - 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); - - /* Get the contents of NP off disk. */ - err = read_node (np, 0); - - if (err) - return err; - else - { - *npp = np; - return 0; - } - - gotit: - diskfs_nref (np); - pthread_rwlock_unlock (&nodecache_lock); - pthread_mutex_lock (&np->lock); + dn->inode = ctx->inode; + dn->dirnode = ctx->dir; *npp = np; return 0; } @@ -162,78 +74,8 @@ error_t diskfs_cached_lookup_in_dirbuf (int inum, struct node **npp, vm_address_t buf) { error_t err; - struct node *np; - struct disknode *dn; - - pthread_rwlock_rdlock (&nodecache_lock); - for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext) - if (np->cache_id == inum) - { - 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) - return ENOMEM; - - dn->pager = 0; - dn->first = 0; - dn->last = 0; - dn->length_of_chain = 0; - dn->chain_complete = 0; - dn->chain_extension_lock = PTHREAD_SPINLOCK_INITIALIZER; - pthread_rwlock_init (&dn->alloc_lock, NULL); - pthread_rwlock_init (&dn->dirent_lock, NULL); - - /* Create the new node. */ - np = diskfs_make_node (dn); - np->cache_id = inum; - np->dn->inode = vi_lookup(inum); - - 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); - - /* Get the contents of NP off disk. */ - err = read_node (np, buf); - - if (err) - return err; - else - { - *npp = np; - return 0; - } -} - -/* Lookup node INUM (which must have a reference already) and return - it without allocating any new references. */ -struct node * -ifind (ino_t inum) -{ - struct node *np; - - pthread_rwlock_rdlock (&nodecache_lock); - np = lookup (inum); - pthread_rwlock_unlock (&nodecache_lock); - - assert (np); - return np; + struct lookup_context ctx = { buf: buf, inode: vi_lookup (inum) }; + return diskfs_cached_lookup_context (inum, npp, &ctx); } /* The last reference to a node has gone away; drop it from the hash @@ -258,41 +100,15 @@ diskfs_node_norefs (struct node *np) assert (!np->dn->pager); - free (np->dn); free (np); } -/* The last hard reference to a node has gone away; arrange to have - all the weak references dropped that can be. */ +/* The user must define this function if she wants to use the node + cache. The last hard reference to a node has gone away; arrange to + have all the weak references dropped that can be. */ void -diskfs_try_dropping_softrefs (struct node *np) +diskfs_user_try_dropping_softrefs (struct node *np) { - pthread_rwlock_wrlock (&nodecache_lock); - if (np->dn->hprevp != NULL) - { - /* Check if someone reacquired a reference through the - nodehash. */ - 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. */ - 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; - np->dn->hprevp = NULL; - nodehash_nr_items -= 1; - diskfs_nrele_light (np); - } - pthread_rwlock_unlock (&nodecache_lock); - drop_pager_softrefs (np); } @@ -310,9 +126,10 @@ diskfs_new_hardrefs (struct node *np) allow_pager_softrefs (np); } -/* Read stat information out of the directory entry. */ -static error_t -read_node (struct node *np, vm_address_t buf) +/* The user must define this function if she wants to use the node + cache. Read stat information out of the on-disk node. */ +error_t +diskfs_user_read_node (struct node *np, struct lookup_context *ctx) { /* XXX This needs careful investigation. */ error_t err; @@ -323,6 +140,7 @@ read_node (struct node *np, vm_address_t buf) struct vi_key vk = vi_key(np->dn->inode); vm_prot_t prot = VM_PROT_READ; memory_object_t memobj; + vm_address_t buf = ctx->buf; vm_size_t buflen = 0; int our_buf = 0; @@ -359,7 +177,7 @@ read_node (struct node *np, vm_address_t buf) /* FIXME: We know intimately that the parent dir is locked by libdiskfs. The only case it is not locked is for NFS (fsys_getfile) and we disabled that. */ - dp = ifind (vk.dir_inode); + dp = diskfs_cached_ifind (vk.dir_inode); assert (dp); /* Map in the directory contents. */ @@ -572,7 +390,7 @@ error_t diskfs_node_reload (struct node *node) { struct cluster_chain *last = node->dn->first; - + static struct lookup_context ctx = { buf: 0 }; while (last) { struct cluster_chain *next = last->next; @@ -580,61 +398,8 @@ diskfs_node_reload (struct node *node) last = next; } flush_node_pager (node); - read_node (node, 0); - return 0; -} - -/* For each active node, call FUN. The node is to be locked around the call - to FUN. If FUN returns non-zero for any node, then immediately stop, and - return that value. */ -error_t -diskfs_node_iterate (error_t (*fun)(struct node *)) -{ - error_t err = 0; - int n; - size_t num_nodes; - struct node *node, **node_list, **p; - - 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 - nodecache_lock, but we can't hold this while locking the - individual node locks). */ - - num_nodes = nodehash_nr_items; - - node_list = alloca (num_nodes * sizeof (struct node *)); - p = node_list; - for (n = 0; n < INOHSZ; n++) - for (node = nodehash[n]; node; node = node->dn->hnext) - { - *p++ = 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. */ - refcounts_ref (&node->refcounts, NULL); - } - - pthread_rwlock_unlock (&nodecache_lock); - - p = node_list; - while (num_nodes-- > 0) - { - node = *p++; - if (!err) - { - pthread_mutex_lock (&node->lock); - err = (*fun)(node); - pthread_mutex_unlock (&node->lock); - } - diskfs_nrele (node); - } - - return err; + return diskfs_user_read_node (node, &ctx); } /* Write all active disknodes into the ext2_inode pager. */ @@ -812,7 +577,8 @@ diskfs_alloc_node (struct node *dir, mode_t mode, struct node **node) ino_t inum; inode_t inode; struct node *np; - + struct lookup_context ctx = { dir: dir }; + assert (!diskfs_readonly); /* FIXME: We use a magic key here that signals read_node that we are @@ -821,12 +587,10 @@ diskfs_alloc_node (struct node *dir, mode_t mode, struct node **node) if (err) return err; - err = diskfs_cached_lookup (inum, &np); + err = diskfs_cached_lookup_context (inum, &np, &ctx); if (err) return err; - /* FIXME: We know that readnode couldn't put this in. */ - np->dn->dirnode = dir; refcounts_ref (&dir->refcounts, NULL); *node = np; diff --git a/fatfs/main.c b/fatfs/main.c index 2bbcdfaa..00c56bc5 100644 --- a/fatfs/main.c +++ b/fatfs/main.c @@ -143,7 +143,7 @@ fetch_root () { error_t err; ino_t inum; - inode_t inode; + struct lookup_context ctx; memset (&dr_root_node, 0, sizeof(struct dirrect)); @@ -196,13 +196,13 @@ fetch_root () from the vi_zero_key (in the dir_offset value) as well as all normal virtual inode keys (in the dir_inode value). Enter the disknode into the inode table. */ - err = vi_new ((struct vi_key) {0, 1}, &inum, &inode); + err = vi_new ((struct vi_key) {0, 1}, &inum, &ctx.inode); assert_perror (err); /* Allocate a node for the root directory disknode in diskfs_root_node. */ if (!err) - err = diskfs_cached_lookup (inum, &diskfs_root_node); + err = diskfs_cached_lookup_context (inum, &diskfs_root_node, &ctx); assert_perror (err); -- cgit v1.2.3