diff options
Diffstat (limited to 'fs')
-rw-r--r-- | fs/kernfs/dir.c | 101 | ||||
-rw-r--r-- | fs/kernfs/file.c | 4 | ||||
-rw-r--r-- | fs/kernfs/inode.c | 4 | ||||
-rw-r--r-- | fs/kernfs/kernfs-internal.h | 2 | ||||
-rw-r--r-- | fs/kernfs/mount.c | 102 |
5 files changed, 114 insertions, 99 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 6ebae6bbe6a5..b2d9f79c4a7c 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -508,10 +508,6 @@ void kernfs_put(struct kernfs_node *kn) struct kernfs_node *parent; struct kernfs_root *root; - /* - * kernfs_node is freed with ->count 0, kernfs_find_and_get_node_by_ino - * depends on this to filter reused stale node - */ if (!kn || !atomic_dec_and_test(&kn->count)) return; root = kernfs_root(kn); @@ -536,7 +532,7 @@ void kernfs_put(struct kernfs_node *kn) kmem_cache_free(kernfs_iattrs_cache, kn->iattr); } spin_lock(&kernfs_idr_lock); - idr_remove(&root->ino_idr, kn->id.ino); + idr_remove(&root->ino_idr, (u32)kernfs_ino(kn)); spin_unlock(&kernfs_idr_lock); kmem_cache_free(kernfs_node_cache, kn); @@ -621,8 +617,7 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, unsigned flags) { struct kernfs_node *kn; - u32 gen; - int cursor; + u32 id_highbits; int ret; name = kstrdup_const(name, GFP_KERNEL); @@ -635,23 +630,19 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, idr_preload(GFP_KERNEL); spin_lock(&kernfs_idr_lock); - cursor = idr_get_cursor(&root->ino_idr); ret = idr_alloc_cyclic(&root->ino_idr, kn, 1, 0, GFP_ATOMIC); - if (ret >= 0 && ret < cursor) - root->next_generation++; - gen = root->next_generation; + if (ret >= 0 && ret < root->last_id_lowbits) + root->id_highbits++; + id_highbits = root->id_highbits; + root->last_id_lowbits = ret; spin_unlock(&kernfs_idr_lock); idr_preload_end(); if (ret < 0) goto err_out2; - kn->id.ino = ret; - kn->id.generation = gen; - /* - * set ino first. This RELEASE is paired with atomic_inc_not_zero in - * kernfs_find_and_get_node_by_ino - */ - atomic_set_release(&kn->count, 1); + kn->id = (u64)id_highbits << 32 | ret; + + atomic_set(&kn->count, 1); atomic_set(&kn->active, KN_DEACTIVATED_BIAS); RB_CLEAR_NODE(&kn->rb); @@ -680,7 +671,7 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, return kn; err_out3: - idr_remove(&root->ino_idr, kn->id.ino); + idr_remove(&root->ino_idr, (u32)kernfs_ino(kn)); err_out2: kmem_cache_free(kernfs_node_cache, kn); err_out1: @@ -705,50 +696,52 @@ struct kernfs_node *kernfs_new_node(struct kernfs_node *parent, } /* - * kernfs_find_and_get_node_by_ino - get kernfs_node from inode number + * kernfs_find_and_get_node_by_id - get kernfs_node from node id * @root: the kernfs root - * @ino: inode number + * @id: the target node id + * + * @id's lower 32bits encode ino and upper gen. If the gen portion is + * zero, all generations are matched. * * RETURNS: * NULL on failure. Return a kernfs node with reference counter incremented */ -struct kernfs_node *kernfs_find_and_get_node_by_ino(struct kernfs_root *root, - unsigned int ino) +struct kernfs_node *kernfs_find_and_get_node_by_id(struct kernfs_root *root, + u64 id) { struct kernfs_node *kn; + ino_t ino = kernfs_id_ino(id); + u32 gen = kernfs_id_gen(id); - rcu_read_lock(); - kn = idr_find(&root->ino_idr, ino); + spin_lock(&kernfs_idr_lock); + + kn = idr_find(&root->ino_idr, (u32)ino); if (!kn) - goto out; + goto err_unlock; - /* - * Since kernfs_node is freed in RCU, it's possible an old node for ino - * is freed, but reused before RCU grace period. But a freed node (see - * kernfs_put) or an incompletedly initialized node (see - * __kernfs_new_node) should have 'count' 0. We can use this fact to - * filter out such node. - */ - if (!atomic_inc_not_zero(&kn->count)) { - kn = NULL; - goto out; + if (sizeof(ino_t) >= sizeof(u64)) { + /* we looked up with the low 32bits, compare the whole */ + if (kernfs_ino(kn) != ino) + goto err_unlock; + } else { + /* 0 matches all generations */ + if (unlikely(gen && kernfs_gen(kn) != gen)) + goto err_unlock; } /* - * The node could be a new node or a reused node. If it's a new node, - * we are ok. If it's reused because of RCU (because of - * SLAB_TYPESAFE_BY_RCU), the __kernfs_new_node always sets its 'ino' - * before 'count'. So if 'count' is uptodate, 'ino' should be uptodate, - * hence we can use 'ino' to filter stale node. + * ACTIVATED is protected with kernfs_mutex but it was clear when + * @kn was added to idr and we just wanna see it set. No need to + * grab kernfs_mutex. */ - if (kn->id.ino != ino) - goto out; - rcu_read_unlock(); + if (unlikely(!(kn->flags & KERNFS_ACTIVATED) || + !atomic_inc_not_zero(&kn->count))) + goto err_unlock; + spin_unlock(&kernfs_idr_lock); return kn; -out: - rcu_read_unlock(); - kernfs_put(kn); +err_unlock: + spin_unlock(&kernfs_idr_lock); return NULL; } @@ -962,7 +955,17 @@ struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, idr_init(&root->ino_idr); INIT_LIST_HEAD(&root->supers); - root->next_generation = 1; + + /* + * On 64bit ino setups, id is ino. On 32bit, low 32bits are ino. + * High bits generation. The starting value for both ino and + * genenration is 1. Initialize upper 32bit allocation + * accordingly. + */ + if (sizeof(ino_t) >= sizeof(u64)) + root->id_highbits = 0; + else + root->id_highbits = 1; kn = __kernfs_new_node(root, NULL, "", S_IFDIR | S_IRUGO | S_IXUGO, GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, @@ -1678,7 +1681,7 @@ static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx) const char *name = pos->name; unsigned int type = dt_type(pos); int len = strlen(name); - ino_t ino = pos->id.ino; + ino_t ino = kernfs_ino(pos); ctx->pos = pos->hash; file->private_data = pos; diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c index e8c792b49616..34366db3620d 100644 --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -892,7 +892,7 @@ repeat: * have the matching @file available. Look up the inodes * and generate the events manually. */ - inode = ilookup(info->sb, kn->id.ino); + inode = ilookup(info->sb, kernfs_ino(kn)); if (!inode) continue; @@ -901,7 +901,7 @@ repeat: if (parent) { struct inode *p_inode; - p_inode = ilookup(info->sb, parent->id.ino); + p_inode = ilookup(info->sb, kernfs_ino(parent)); if (p_inode) { fsnotify(p_inode, FS_MODIFY | FS_EVENT_ON_CHILD, inode, FSNOTIFY_EVENT_INODE, &name, 0); diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c index f3eaa8869f42..eac277c63d42 100644 --- a/fs/kernfs/inode.c +++ b/fs/kernfs/inode.c @@ -201,7 +201,7 @@ static void kernfs_init_inode(struct kernfs_node *kn, struct inode *inode) inode->i_private = kn; inode->i_mapping->a_ops = &kernfs_aops; inode->i_op = &kernfs_iops; - inode->i_generation = kn->id.generation; + inode->i_generation = kernfs_gen(kn); set_default_inode_attr(inode, kn->mode); kernfs_refresh_inode(kn, inode); @@ -247,7 +247,7 @@ struct inode *kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn) { struct inode *inode; - inode = iget_locked(sb, kn->id.ino); + inode = iget_locked(sb, kernfs_ino(kn)); if (inode && (inode->i_state & I_NEW)) kernfs_init_inode(kn, inode); diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h index 02ce570a9a3c..2f3c51d55261 100644 --- a/fs/kernfs/kernfs-internal.h +++ b/fs/kernfs/kernfs-internal.h @@ -109,8 +109,6 @@ struct kernfs_node *kernfs_new_node(struct kernfs_node *parent, const char *name, umode_t mode, kuid_t uid, kgid_t gid, unsigned flags); -struct kernfs_node *kernfs_find_and_get_node_by_ino(struct kernfs_root *root, - unsigned int ino); /* * file.c diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c index 6c12fac2c287..4d31503abaee 100644 --- a/fs/kernfs/mount.c +++ b/fs/kernfs/mount.c @@ -53,63 +53,85 @@ const struct super_operations kernfs_sops = { .show_path = kernfs_sop_show_path, }; -/* - * Similar to kernfs_fh_get_inode, this one gets kernfs node from inode - * number and generation - */ -struct kernfs_node *kernfs_get_node_by_id(struct kernfs_root *root, - const union kernfs_node_id *id) +static int kernfs_encode_fh(struct inode *inode, __u32 *fh, int *max_len, + struct inode *parent) { - struct kernfs_node *kn; + struct kernfs_node *kn = inode->i_private; - kn = kernfs_find_and_get_node_by_ino(root, id->ino); - if (!kn) - return NULL; - if (kn->id.generation != id->generation) { - kernfs_put(kn); - return NULL; + if (*max_len < 2) { + *max_len = 2; + return FILEID_INVALID; } - return kn; + + *max_len = 2; + *(u64 *)fh = kn->id; + return FILEID_KERNFS; } -static struct inode *kernfs_fh_get_inode(struct super_block *sb, - u64 ino, u32 generation) +static struct dentry *__kernfs_fh_to_dentry(struct super_block *sb, + struct fid *fid, int fh_len, + int fh_type, bool get_parent) { struct kernfs_super_info *info = kernfs_info(sb); - struct inode *inode; struct kernfs_node *kn; + struct inode *inode; + u64 id; - if (ino == 0) - return ERR_PTR(-ESTALE); + if (fh_len < 2) + return NULL; + + switch (fh_type) { + case FILEID_KERNFS: + id = *(u64 *)fid; + break; + case FILEID_INO32_GEN: + case FILEID_INO32_GEN_PARENT: + /* + * blk_log_action() exposes "LOW32,HIGH32" pair without + * type and userland can call us with generic fid + * constructed from them. Combine it back to ID. See + * blk_log_action(). + */ + id = ((u64)fid->i32.gen << 32) | fid->i32.ino; + break; + default: + return NULL; + } - kn = kernfs_find_and_get_node_by_ino(info->root, ino); + kn = kernfs_find_and_get_node_by_id(info->root, id); if (!kn) return ERR_PTR(-ESTALE); + + if (get_parent) { + struct kernfs_node *parent; + + parent = kernfs_get_parent(kn); + kernfs_put(kn); + kn = parent; + if (!kn) + return ERR_PTR(-ESTALE); + } + inode = kernfs_get_inode(sb, kn); kernfs_put(kn); if (!inode) return ERR_PTR(-ESTALE); - if (generation && inode->i_generation != generation) { - /* we didn't find the right inode.. */ - iput(inode); - return ERR_PTR(-ESTALE); - } - return inode; + return d_obtain_alias(inode); } -static struct dentry *kernfs_fh_to_dentry(struct super_block *sb, struct fid *fid, - int fh_len, int fh_type) +static struct dentry *kernfs_fh_to_dentry(struct super_block *sb, + struct fid *fid, int fh_len, + int fh_type) { - return generic_fh_to_dentry(sb, fid, fh_len, fh_type, - kernfs_fh_get_inode); + return __kernfs_fh_to_dentry(sb, fid, fh_len, fh_type, false); } -static struct dentry *kernfs_fh_to_parent(struct super_block *sb, struct fid *fid, - int fh_len, int fh_type) +static struct dentry *kernfs_fh_to_parent(struct super_block *sb, + struct fid *fid, int fh_len, + int fh_type) { - return generic_fh_to_parent(sb, fid, fh_len, fh_type, - kernfs_fh_get_inode); + return __kernfs_fh_to_dentry(sb, fid, fh_len, fh_type, true); } static struct dentry *kernfs_get_parent_dentry(struct dentry *child) @@ -120,6 +142,7 @@ static struct dentry *kernfs_get_parent_dentry(struct dentry *child) } static const struct export_operations kernfs_export_ops = { + .encode_fh = kernfs_encode_fh, .fh_to_dentry = kernfs_fh_to_dentry, .fh_to_parent = kernfs_fh_to_parent, .get_parent = kernfs_get_parent_dentry, @@ -363,18 +386,9 @@ void kernfs_kill_sb(struct super_block *sb) void __init kernfs_init(void) { - - /* - * the slab is freed in RCU context, so kernfs_find_and_get_node_by_ino - * can access the slab lock free. This could introduce stale nodes, - * please see how kernfs_find_and_get_node_by_ino filters out stale - * nodes. - */ kernfs_node_cache = kmem_cache_create("kernfs_node_cache", sizeof(struct kernfs_node), - 0, - SLAB_PANIC | SLAB_TYPESAFE_BY_RCU, - NULL); + 0, SLAB_PANIC, NULL); /* Creates slab cache for kernfs inode attributes */ kernfs_iattrs_cache = kmem_cache_create("kernfs_iattrs_cache", |