1 files changed, 59 insertions, 69 deletions

diff --git a/fs/file.c b/fs/file.c
index 4a78f981557a..60a45e9f5323 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -34,7 +34,7 @@ static void *alloc_fdmem(size_t size)
          * vmalloc() if the allocation size will be considered "large" by the VM.
          */
         if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
-                void *data = kmalloc(size, GFP_KERNEL|__GFP_NOWARN);
+                void *data = kmalloc(size, GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY);
                 if (data != NULL)
                         return data;
         }
@@ -348,21 +348,16 @@ out:
         return NULL;
 }
 
-static void close_files(struct files_struct * files)
+static struct fdtable *close_files(struct files_struct * files)
 {
-        int i, j;
-        struct fdtable *fdt;
-
-        j = 0;
-
         /*
          * It is safe to dereference the fd table without RCU or
          * ->file_lock because this is the last reference to the
-         * files structure.  But use RCU to shut RCU-lockdep up.
+         * files structure.
          */
-        rcu_read_lock();
-        fdt = files_fdtable(files);
-        rcu_read_unlock();
+        struct fdtable *fdt = rcu_dereference_raw(files->fdt);
+        int i, j = 0;
+
         for (;;) {
                 unsigned long set;
                 i = j * BITS_PER_LONG;
@@ -381,6 +376,8 @@ static void close_files(struct files_struct * files)
                         set >>= 1;
                 }
         }
+
+        return fdt;
 }
 
 struct files_struct *get_files_struct(struct task_struct *task)
@@ -398,14 +395,9 @@ struct files_struct *get_files_struct(struct task_struct *task)
 
 void put_files_struct(struct files_struct *files)
 {
-        struct fdtable *fdt;
-
         if (atomic_dec_and_test(&files->count)) {
-                close_files(files);
-                /* not really needed, since nobody can see us */
-                rcu_read_lock();
-                fdt = files_fdtable(files);
-                rcu_read_unlock();
+                struct fdtable *fdt = close_files(files);
+
                 /* free the arrays if they are not embedded */
                 if (fdt != &files->fdtab)
                         __free_fdtable(fdt);
@@ -645,16 +637,16 @@ void do_close_on_exec(struct files_struct *files)
         spin_unlock(&files->file_lock);
 }
 
-struct file *fget(unsigned int fd)
+static struct file *__fget(unsigned int fd, fmode_t mask)
 {
-        struct file *file;
         struct files_struct *files = current->files;
+        struct file *file;
 
         rcu_read_lock();
         file = fcheck_files(files, fd);
         if (file) {
                 /* File object ref couldn't be taken */
-                if (file->f_mode & FMODE_PATH ||
+                if ((file->f_mode & mask) ||
                     !atomic_long_inc_not_zero(&file->f_count))
                         file = NULL;
         }
@@ -663,25 +655,16 @@ struct file *fget(unsigned int fd)
         return file;
 }
 
+struct file *fget(unsigned int fd)
+{
+        return __fget(fd, FMODE_PATH);
+}
 EXPORT_SYMBOL(fget);
 
 struct file *fget_raw(unsigned int fd)
 {
-        struct file *file;
-        struct files_struct *files = current->files;
-
-        rcu_read_lock();
-        file = fcheck_files(files, fd);
-        if (file) {
-                /* File object ref couldn't be taken */
-                if (!atomic_long_inc_not_zero(&file->f_count))
-                        file = NULL;
-        }
-        rcu_read_unlock();
-
-        return file;
+        return __fget(fd, 0);
 }
-
 EXPORT_SYMBOL(fget_raw);
 
 /*
@@ -700,58 +683,65 @@ EXPORT_SYMBOL(fget_raw);
  * The fput_needed flag returned by fget_light should be passed to the
  * corresponding fput_light.
  */
-struct file *fget_light(unsigned int fd, int *fput_needed)
+static unsigned long __fget_light(unsigned int fd, fmode_t mask)
 {
-        struct file *file;
         struct files_struct *files = current->files;
+        struct file *file;
 
-        *fput_needed = 0;
         if (atomic_read(&files->count) == 1) {
-                file = fcheck_files(files, fd);
-                if (file && (file->f_mode & FMODE_PATH))
-                        file = NULL;
+                file = __fcheck_files(files, fd);
+                if (!file || unlikely(file->f_mode & mask))
+                        return 0;
+                return (unsigned long)file;
         } else {
-                rcu_read_lock();
-                file = fcheck_files(files, fd);
-                if (file) {
-                        if (!(file->f_mode & FMODE_PATH) &&
-                            atomic_long_inc_not_zero(&file->f_count))
-                                *fput_needed = 1;
-                        else
-                                /* Didn't get the reference, someone's freed */
-                                file = NULL;
-                }
-                rcu_read_unlock();
+                file = __fget(fd, mask);
+                if (!file)
+                        return 0;
+                return FDPUT_FPUT | (unsigned long)file;
         }
+}
+unsigned long __fdget(unsigned int fd)
+{
+        return __fget_light(fd, FMODE_PATH);
+}
+EXPORT_SYMBOL(__fdget);
 
-        return file;
+unsigned long __fdget_raw(unsigned int fd)
+{
+        return __fget_light(fd, 0);
 }
-EXPORT_SYMBOL(fget_light);
 
-struct file *fget_raw_light(unsigned int fd, int *fput_needed)
+unsigned long __fdget_pos(unsigned int fd)
 {
-        struct file *file;
         struct files_struct *files = current->files;
+        struct file *file;
+        unsigned long v;
 
-        *fput_needed = 0;
         if (atomic_read(&files->count) == 1) {
-                file = fcheck_files(files, fd);
+                file = __fcheck_files(files, fd);
+                v = 0;
         } else {
-                rcu_read_lock();
-                file = fcheck_files(files, fd);
-                if (file) {
-                        if (atomic_long_inc_not_zero(&file->f_count))
-                                *fput_needed = 1;
-                        else
-                                /* Didn't get the reference, someone's freed */
-                                file = NULL;
-                }
-                rcu_read_unlock();
+                file = __fget(fd, 0);
+                v = FDPUT_FPUT;
         }
+        if (!file)
+                return 0;
 
-        return file;
+        if (file->f_mode & FMODE_ATOMIC_POS) {
+                if (file_count(file) > 1) {
+                        v |= FDPUT_POS_UNLOCK;
+                        mutex_lock(&file->f_pos_lock);
+                }
+        }
+        return v | (unsigned long)file;
 }
 
+/*
+ * We only lock f_pos if we have threads or if the file might be
+ * shared with another process. In both cases we'll have an elevated
+ * file count (done either by fdget() or by fork()).
+ */
+
 void set_close_on_exec(unsigned int fd, int flag)
 {
         struct files_struct *files = current->files;