X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=fs%2Fdcache.c;h=678d39deb60770dffb5cbbbc0de1e84d6e139f36;hb=2605a103cadb29053d6bc7e81c7de802ec75ce6c;hp=d68631f18df122824a0d36a307c647f15931c7bd;hpb=f90203e0cf0d5a8b027d511af318bb3db4758fe2;p=pandora-kernel.git diff --git a/fs/dcache.c b/fs/dcache.c index d68631f18df1..678d39deb607 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -21,7 +21,6 @@ #include #include #include -#include #include #include #include @@ -121,6 +120,28 @@ static void dentry_iput(struct dentry * dentry) } } +/** + * d_kill - kill dentry and return parent + * @dentry: dentry to kill + * + * Called with dcache_lock and d_lock, releases both. The dentry must + * already be unhashed and removed from the LRU. + * + * If this is the root of the dentry tree, return NULL. + */ +static struct dentry *d_kill(struct dentry *dentry) +{ + struct dentry *parent; + + list_del(&dentry->d_u.d_child); + dentry_stat.nr_dentry--; /* For d_free, below */ + /*drops the locks, at that point nobody can reach this dentry */ + dentry_iput(dentry); + parent = dentry->d_parent; + d_free(dentry); + return dentry == parent ? NULL : parent; +} + /* * This is dput * @@ -189,28 +210,17 @@ repeat: unhash_it: __d_drop(dentry); - -kill_it: { - struct dentry *parent; - - /* If dentry was on d_lru list - * delete it from there - */ - if (!list_empty(&dentry->d_lru)) { - list_del(&dentry->d_lru); - dentry_stat.nr_unused--; - } - list_del(&dentry->d_u.d_child); - dentry_stat.nr_dentry--; /* For d_free, below */ - /*drops the locks, at that point nobody can reach this dentry */ - dentry_iput(dentry); - parent = dentry->d_parent; - d_free(dentry); - if (dentry == parent) - return; - dentry = parent; - goto repeat; +kill_it: + /* If dentry was on d_lru list + * delete it from there + */ + if (!list_empty(&dentry->d_lru)) { + list_del(&dentry->d_lru); + dentry_stat.nr_unused--; } + dentry = d_kill(dentry); + if (dentry) + goto repeat; } /** @@ -371,22 +381,40 @@ restart: * Throw away a dentry - free the inode, dput the parent. This requires that * the LRU list has already been removed. * + * If prune_parents is true, try to prune ancestors as well. + * * Called with dcache_lock, drops it and then regains. * Called with dentry->d_lock held, drops it. */ -static void prune_one_dentry(struct dentry * dentry) +static void prune_one_dentry(struct dentry * dentry, int prune_parents) { - struct dentry * parent; - __d_drop(dentry); - list_del(&dentry->d_u.d_child); - dentry_stat.nr_dentry--; /* For d_free, below */ - dentry_iput(dentry); - parent = dentry->d_parent; - d_free(dentry); - if (parent != dentry) - dput(parent); + dentry = d_kill(dentry); + if (!prune_parents) { + dput(dentry); + spin_lock(&dcache_lock); + return; + } + + /* + * Prune ancestors. Locking is simpler than in dput(), + * because dcache_lock needs to be taken anyway. + */ spin_lock(&dcache_lock); + while (dentry) { + if (!atomic_dec_and_lock(&dentry->d_count, &dentry->d_lock)) + return; + + if (dentry->d_op && dentry->d_op->d_delete) + dentry->d_op->d_delete(dentry); + if (!list_empty(&dentry->d_lru)) { + list_del(&dentry->d_lru); + dentry_stat.nr_unused--; + } + __d_drop(dentry); + dentry = d_kill(dentry); + spin_lock(&dcache_lock); + } } /** @@ -394,6 +422,7 @@ static void prune_one_dentry(struct dentry * dentry) * @count: number of entries to try and free * @sb: if given, ignore dentries for other superblocks * which are being unmounted. + * @prune_parents: if true, try to prune ancestors as well in one go * * Shrink the dcache. This is done when we need * more memory, or simply when we need to unmount @@ -404,7 +433,7 @@ static void prune_one_dentry(struct dentry * dentry) * all the dentries are in use. */ -static void prune_dcache(int count, struct super_block *sb) +static void prune_dcache(int count, struct super_block *sb, int prune_parents) { spin_lock(&dcache_lock); for (; count ; count--) { @@ -464,7 +493,7 @@ static void prune_dcache(int count, struct super_block *sb) * without taking the s_umount lock (I already hold it). */ if (sb && dentry->d_sb == sb) { - prune_one_dentry(dentry); + prune_one_dentry(dentry, prune_parents); continue; } /* @@ -479,7 +508,7 @@ static void prune_dcache(int count, struct super_block *sb) s_umount = &dentry->d_sb->s_umount; if (down_read_trylock(s_umount)) { if (dentry->d_sb->s_root != NULL) { - prune_one_dentry(dentry); + prune_one_dentry(dentry, prune_parents); up_read(s_umount); continue; } @@ -550,7 +579,7 @@ repeat: spin_unlock(&dentry->d_lock); continue; } - prune_one_dentry(dentry); + prune_one_dentry(dentry, 1); cond_resched_lock(&dcache_lock); goto repeat; } @@ -829,7 +858,7 @@ void shrink_dcache_parent(struct dentry * parent) int found; while ((found = select_parent(parent)) != 0) - prune_dcache(found, parent->d_sb); + prune_dcache(found, parent->d_sb, 1); } /* @@ -849,11 +878,16 @@ static int shrink_dcache_memory(int nr, gfp_t gfp_mask) if (nr) { if (!(gfp_mask & __GFP_FS)) return -1; - prune_dcache(nr, NULL); + prune_dcache(nr, NULL, 1); } return (dentry_stat.nr_unused / 100) * sysctl_vfs_cache_pressure; } +static struct shrinker dcache_shrinker = { + .shrink = shrink_dcache_memory, + .seeks = DEFAULT_SEEKS, +}; + /** * d_alloc - allocate a dcache entry * @parent: parent of entry to allocate @@ -1823,6 +1857,16 @@ char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt, struct vfsmount *rootmnt; struct dentry *root; + /* + * We have various synthetic filesystems that never get mounted. On + * these filesystems dentries are never used for lookup purposes, and + * thus don't need to be hashed. They also don't need a name until a + * user wants to identify the object in /proc/pid/fd/. The little hack + * below allows us to generate a name for these objects on demand: + */ + if (dentry->d_op && dentry->d_op->d_dname) + return dentry->d_op->d_dname(dentry, buf, buflen); + read_lock(¤t->fs->lock); rootmnt = mntget(current->fs->rootmnt); root = dget(current->fs->root); @@ -1835,6 +1879,27 @@ char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt, return res; } +/* + * Helper function for dentry_operations.d_dname() members + */ +char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen, + const char *fmt, ...) +{ + va_list args; + char temp[64]; + int sz; + + va_start(args, fmt); + sz = vsnprintf(temp, sizeof(temp), fmt, args) + 1; + va_end(args); + + if (sz > sizeof(temp) || sz > buflen) + return ERR_PTR(-ENAMETOOLONG); + + buffer += buflen - sz; + return memcpy(buffer, temp, sz); +} + /* * NOTE! The user-level library version returns a * character pointer. The kernel system call just @@ -2052,14 +2117,10 @@ static void __init dcache_init(unsigned long mempages) * but it is probably not worth it because of the cache nature * of the dcache. */ - dentry_cache = kmem_cache_create("dentry_cache", - sizeof(struct dentry), - 0, - (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| - SLAB_MEM_SPREAD), - NULL, NULL); + dentry_cache = KMEM_CACHE(dentry, + SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD); - set_shrinker(DEFAULT_SEEKS, shrink_dcache_memory); + register_shrinker(&dcache_shrinker); /* Hash may have been set up in dcache_init_early */ if (!hashdist) @@ -2104,10 +2165,10 @@ void __init vfs_caches_init(unsigned long mempages) mempages -= reserve; names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0, - SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); + SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0, - SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); + SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); dcache_init(mempages); inode_init(mempages);