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-rw-r--r--fs/file_table.c69
-rw-r--r--fs/internal.h1
-rw-r--r--fs/open.c2
-rw-r--r--include/linux/fs.h3
4 files changed, 53 insertions, 22 deletions
diff --git a/fs/file_table.c b/fs/file_table.c
index 9b70ed2bbc4e..0cc7bea6b51a 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -52,7 +52,8 @@ static void file_free_rcu(struct rcu_head *head)
static inline void file_free(struct file *f)
{
security_file_free(f);
- percpu_counter_dec(&nr_files);
+ if (!(f->f_mode & FMODE_NOACCOUNT))
+ percpu_counter_dec(&nr_files);
call_rcu(&f->f_u.fu_rcuhead, file_free_rcu);
}
@@ -91,6 +92,34 @@ int proc_nr_files(struct ctl_table *table, int write,
}
#endif
+static struct file *__alloc_file(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_u.fu_rcuhead);
+ return ERR_PTR(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);
+ eventpoll_init_file(f);
+ f->f_flags = flags;
+ f->f_mode = OPEN_FMODE(flags);
+ /* f->f_version: 0 */
+
+ return f;
+}
+
/* Find an unused file structure and return a pointer to it.
* Returns an error pointer if some error happend e.g. we over file
* structures limit, run out of memory or operation is not permitted.
@@ -105,7 +134,6 @@ struct file *alloc_empty_file(int flags, const struct cred *cred)
{
static long old_max;
struct file *f;
- int error;
/*
* Privileged users can go above max_files
@@ -119,26 +147,10 @@ struct file *alloc_empty_file(int flags, const struct cred *cred)
goto over;
}
- 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_u.fu_rcuhead);
- return ERR_PTR(error);
- }
+ f = __alloc_file(flags, cred);
+ if (!IS_ERR(f))
+ percpu_counter_inc(&nr_files);
- 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);
- eventpoll_init_file(f);
- f->f_flags = flags;
- f->f_mode = OPEN_FMODE(flags);
- /* f->f_version: 0 */
- percpu_counter_inc(&nr_files);
return f;
over:
@@ -150,6 +162,21 @@ over:
return ERR_PTR(-ENFILE);
}
+/*
+ * 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.
+ */
+struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred)
+{
+ struct file *f = __alloc_file(flags, cred);
+
+ if (!IS_ERR(f))
+ f->f_mode |= FMODE_NOACCOUNT;
+
+ return f;
+}
+
/**
* alloc_file - allocate and initialize a 'struct file'
*
diff --git a/fs/internal.h b/fs/internal.h
index 52a346903748..442098fa0a84 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -94,6 +94,7 @@ extern void chroot_fs_refs(const struct path *, const struct path *);
* file_table.c
*/
extern struct file *alloc_empty_file(int, const struct cred *);
+extern struct file *alloc_empty_file_noaccount(int, const struct cred *);
/*
* super.c
diff --git a/fs/open.c b/fs/open.c
index dd15711eb658..9c6617dbb2c0 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -928,7 +928,7 @@ EXPORT_SYMBOL(dentry_open);
struct file *open_with_fake_path(const struct path *path, int flags,
struct inode *inode, const struct cred *cred)
{
- struct file *f = alloc_empty_file(flags, cred);
+ struct file *f = alloc_empty_file_noaccount(flags, cred);
if (!IS_ERR(f)) {
int error;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5ce2b413abc6..e1884840d556 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -156,6 +156,9 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
/* File is capable of returning -EAGAIN if I/O will block */
#define FMODE_NOWAIT ((__force fmode_t)0x8000000)
+/* File does not contribute to nr_files count */
+#define FMODE_NOACCOUNT ((__force fmode_t)0x20000000)
+
/*
* Flag for rw_copy_check_uvector and compat_rw_copy_check_uvector
* that indicates that they should check the contents of the iovec are