#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
+#include <linux/filelock.h>
#include <linux/security.h>
#include <linux/cred.h>
#include <linux/eventpoll.h>
#include <linux/percpu_counter.h>
#include <linux/percpu.h>
#include <linux/task_work.h>
-#include <linux/ima.h>
#include <linux/swap.h>
#include <linux/kmemleak.h>
};
/* SLAB cache for file structures */
-static struct kmem_cache *filp_cachep __read_mostly;
+static struct kmem_cache *filp_cachep __ro_after_init;
static struct percpu_counter nr_files __cacheline_aligned_in_smp;
-static void file_free_rcu(struct rcu_head *head)
+/* Container for backing file with optional user path */
+struct backing_file {
+ struct file file;
+ struct path user_path;
+};
+
+static inline struct backing_file *backing_file(struct file *f)
{
- struct file *f = container_of(head, struct file, f_rcuhead);
+ return container_of(f, struct backing_file, file);
+}
- put_cred(f->f_cred);
- kmem_cache_free(filp_cachep, f);
+struct path *backing_file_user_path(struct file *f)
+{
+ return &backing_file(f)->user_path;
}
+EXPORT_SYMBOL_GPL(backing_file_user_path);
static inline void file_free(struct file *f)
{
security_file_free(f);
- if (!(f->f_mode & FMODE_NOACCOUNT))
+ if (likely(!(f->f_mode & FMODE_NOACCOUNT)))
percpu_counter_dec(&nr_files);
- call_rcu(&f->f_rcuhead, file_free_rcu);
+ put_cred(f->f_cred);
+ if (unlikely(f->f_mode & FMODE_BACKING)) {
+ path_put(backing_file_user_path(f));
+ kfree(backing_file(f));
+ } else {
+ kmem_cache_free(filp_cachep, f);
+ }
}
/*
.extra1 = &sysctl_nr_open_min,
.extra2 = &sysctl_nr_open_max,
},
- { }
};
static int __init init_fs_stat_sysctls(void)
fs_initcall(init_fs_stat_sysctls);
#endif
-static struct file *__alloc_file(int flags, const struct cred *cred)
+static int init_file(struct file *f, int flags, const struct cred *cred)
{
- struct file *f;
int error;
- f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL);
- if (unlikely(!f))
- return ERR_PTR(-ENOMEM);
-
f->f_cred = get_cred(cred);
error = security_file_alloc(f);
if (unlikely(error)) {
- file_free_rcu(&f->f_rcuhead);
- return ERR_PTR(error);
+ put_cred(f->f_cred);
+ return error;
}
- atomic_long_set(&f->f_count, 1);
rwlock_init(&f->f_owner.lock);
spin_lock_init(&f->f_lock);
mutex_init(&f->f_pos_lock);
f->f_mode = OPEN_FMODE(flags);
/* f->f_version: 0 */
- return f;
+ /*
+ * We're SLAB_TYPESAFE_BY_RCU so initialize f_count last. While
+ * fget-rcu pattern users need to be able to handle spurious
+ * refcount bumps we should reinitialize the reused file first.
+ */
+ atomic_long_set(&f->f_count, 1);
+ return 0;
}
/* Find an unused file structure and return a pointer to it.
{
static long old_max;
struct file *f;
+ int error;
/*
* Privileged users can go above max_files
goto over;
}
- f = __alloc_file(flags, cred);
- if (!IS_ERR(f))
- percpu_counter_inc(&nr_files);
+ f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL);
+ if (unlikely(!f))
+ return ERR_PTR(-ENOMEM);
+
+ error = init_file(f, flags, cred);
+ if (unlikely(error)) {
+ kmem_cache_free(filp_cachep, f);
+ return ERR_PTR(error);
+ }
+
+ percpu_counter_inc(&nr_files);
return f;
/*
* Variant of alloc_empty_file() that doesn't check and modify nr_files.
*
- * Should not be used unless there's a very good reason to do so.
+ * This is only for kernel internal use, and the allocate file must not be
+ * installed into file tables or such.
*/
struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred)
{
- struct file *f = __alloc_file(flags, cred);
+ struct file *f;
+ int error;
- if (!IS_ERR(f))
- f->f_mode |= FMODE_NOACCOUNT;
+ f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL);
+ if (unlikely(!f))
+ return ERR_PTR(-ENOMEM);
+
+ error = init_file(f, flags, cred);
+ if (unlikely(error)) {
+ kmem_cache_free(filp_cachep, f);
+ return ERR_PTR(error);
+ }
+
+ f->f_mode |= FMODE_NOACCOUNT;
return f;
}
+/*
+ * Variant of alloc_empty_file() that allocates a backing_file container
+ * and doesn't check and modify nr_files.
+ *
+ * This is only for kernel internal use, and the allocate file must not be
+ * installed into file tables or such.
+ */
+struct file *alloc_empty_backing_file(int flags, const struct cred *cred)
+{
+ struct backing_file *ff;
+ int error;
+
+ ff = kzalloc(sizeof(struct backing_file), GFP_KERNEL);
+ if (unlikely(!ff))
+ return ERR_PTR(-ENOMEM);
+
+ error = init_file(&ff->file, flags, cred);
+ if (unlikely(error)) {
+ kfree(ff);
+ return ERR_PTR(error);
+ }
+
+ ff->file.f_mode |= FMODE_BACKING | FMODE_NOACCOUNT;
+ return &ff->file;
+}
+
/**
- * alloc_file - allocate and initialize a 'struct file'
+ * file_init_path - initialize a 'struct file' based on path
*
+ * @file: the file to set up
* @path: the (dentry, vfsmount) pair for the new file
- * @flags: O_... flags with which the new file will be opened
* @fop: the 'struct file_operations' for the new file
*/
-static struct file *alloc_file(const struct path *path, int flags,
- const struct file_operations *fop)
+static void file_init_path(struct file *file, const struct path *path,
+ const struct file_operations *fop)
{
- struct file *file;
-
- file = alloc_empty_file(flags, current_cred());
- if (IS_ERR(file))
- return file;
-
file->f_path = *path;
file->f_inode = path->dentry->d_inode;
file->f_mapping = path->dentry->d_inode->i_mapping;
file->f_op = fop;
if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
i_readcount_inc(path->dentry->d_inode);
+}
+
+/**
+ * alloc_file - allocate and initialize a 'struct file'
+ *
+ * @path: the (dentry, vfsmount) pair for the new file
+ * @flags: O_... flags with which the new file will be opened
+ * @fop: the 'struct file_operations' for the new file
+ */
+static struct file *alloc_file(const struct path *path, int flags,
+ const struct file_operations *fop)
+{
+ struct file *file;
+
+ file = alloc_empty_file(flags, current_cred());
+ if (!IS_ERR(file))
+ file_init_path(file, path, fop);
return file;
}
-struct file *alloc_file_pseudo(struct inode *inode, struct vfsmount *mnt,
- const char *name, int flags,
- const struct file_operations *fops)
+static inline int alloc_path_pseudo(const char *name, struct inode *inode,
+ struct vfsmount *mnt, struct path *path)
{
- static const struct dentry_operations anon_ops = {
- .d_dname = simple_dname
- };
struct qstr this = QSTR_INIT(name, strlen(name));
+
+ path->dentry = d_alloc_pseudo(mnt->mnt_sb, &this);
+ if (!path->dentry)
+ return -ENOMEM;
+ path->mnt = mntget(mnt);
+ d_instantiate(path->dentry, inode);
+ return 0;
+}
+
+struct file *alloc_file_pseudo(struct inode *inode, struct vfsmount *mnt,
+ const char *name, int flags,
+ const struct file_operations *fops)
+{
+ int ret;
struct path path;
struct file *file;
- path.dentry = d_alloc_pseudo(mnt->mnt_sb, &this);
- if (!path.dentry)
- return ERR_PTR(-ENOMEM);
- if (!mnt->mnt_sb->s_d_op)
- d_set_d_op(path.dentry, &anon_ops);
- path.mnt = mntget(mnt);
- d_instantiate(path.dentry, inode);
+ ret = alloc_path_pseudo(name, inode, mnt, &path);
+ if (ret)
+ return ERR_PTR(ret);
+
file = alloc_file(&path, flags, fops);
if (IS_ERR(file)) {
ihold(inode);
}
EXPORT_SYMBOL(alloc_file_pseudo);
+struct file *alloc_file_pseudo_noaccount(struct inode *inode,
+ struct vfsmount *mnt, const char *name,
+ int flags,
+ const struct file_operations *fops)
+{
+ int ret;
+ struct path path;
+ struct file *file;
+
+ ret = alloc_path_pseudo(name, inode, mnt, &path);
+ if (ret)
+ return ERR_PTR(ret);
+
+ file = alloc_empty_file_noaccount(flags, current_cred());
+ if (IS_ERR(file)) {
+ ihold(inode);
+ path_put(&path);
+ return file;
+ }
+ file_init_path(file, &path, fops);
+ return file;
+}
+EXPORT_SYMBOL_GPL(alloc_file_pseudo_noaccount);
+
struct file *alloc_file_clone(struct file *base, int flags,
const struct file_operations *fops)
{
eventpoll_release(file);
locks_remove_file(file);
- ima_file_free(file);
+ security_file_release(file);
if (unlikely(file->f_flags & FASYNC)) {
if (file->f_op->fasync)
file->f_op->fasync(-1, file, 0);
}
fops_put(file->f_op);
put_pid(file->f_owner.pid);
- if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
- i_readcount_dec(inode);
- if (mode & FMODE_WRITER) {
- put_write_access(inode);
- __mnt_drop_write(mnt);
- }
+ put_file_access(file);
dput(dentry);
if (unlikely(mode & FMODE_NEED_UNMOUNT))
dissolve_on_fput(mnt);
static void ____fput(struct callback_head *work)
{
- __fput(container_of(work, struct file, f_rcuhead));
+ __fput(container_of(work, struct file, f_task_work));
}
/*
if (atomic_long_dec_and_test(&file->f_count)) {
struct task_struct *task = current;
+ if (unlikely(!(file->f_mode & (FMODE_BACKING | FMODE_OPENED)))) {
+ file_free(file);
+ return;
+ }
if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) {
- init_task_work(&file->f_rcuhead, ____fput);
- if (!task_work_add(task, &file->f_rcuhead, TWA_RESUME))
+ init_task_work(&file->f_task_work, ____fput);
+ if (!task_work_add(task, &file->f_task_work, TWA_RESUME))
return;
/*
* After this task has run exit_task_work(),
*/
void __fput_sync(struct file *file)
{
- if (atomic_long_dec_and_test(&file->f_count)) {
- struct task_struct *task = current;
- BUG_ON(!(task->flags & PF_KTHREAD));
+ if (atomic_long_dec_and_test(&file->f_count))
__fput(file);
- }
}
EXPORT_SYMBOL(fput);
void __init files_init(void)
{
filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0,
- SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT, NULL);
+ SLAB_TYPESAFE_BY_RCU | SLAB_HWCACHE_ALIGN |
+ SLAB_PANIC | SLAB_ACCOUNT, NULL);
percpu_counter_init(&nr_files, 0, GFP_KERNEL);
}
projects / linux-2.6-microblaze.git / blobdiff