take fget() and friends to fs/file.c
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Родитель
f869e8a7f7
Коммит
0ee8cdfe6a
106
fs/file.c
106
fs/file.c
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@ -625,3 +625,109 @@ void fd_install(unsigned int fd, struct file *file)
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}
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}
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EXPORT_SYMBOL(fd_install);
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EXPORT_SYMBOL(fd_install);
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struct file *fget(unsigned int fd)
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{
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struct file *file;
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struct files_struct *files = current->files;
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rcu_read_lock();
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file = fcheck_files(files, fd);
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if (file) {
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/* File object ref couldn't be taken */
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if (file->f_mode & FMODE_PATH ||
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!atomic_long_inc_not_zero(&file->f_count))
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file = NULL;
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}
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rcu_read_unlock();
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return file;
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}
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EXPORT_SYMBOL(fget);
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struct file *fget_raw(unsigned int fd)
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{
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struct file *file;
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struct files_struct *files = current->files;
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rcu_read_lock();
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file = fcheck_files(files, fd);
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if (file) {
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/* File object ref couldn't be taken */
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if (!atomic_long_inc_not_zero(&file->f_count))
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file = NULL;
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}
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rcu_read_unlock();
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return file;
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}
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EXPORT_SYMBOL(fget_raw);
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/*
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* Lightweight file lookup - no refcnt increment if fd table isn't shared.
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*
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* You can use this instead of fget if you satisfy all of the following
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* conditions:
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* 1) You must call fput_light before exiting the syscall and returning control
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* to userspace (i.e. you cannot remember the returned struct file * after
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* returning to userspace).
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* 2) You must not call filp_close on the returned struct file * in between
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* calls to fget_light and fput_light.
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* 3) You must not clone the current task in between the calls to fget_light
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* and fput_light.
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*
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* The fput_needed flag returned by fget_light should be passed to the
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* corresponding fput_light.
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*/
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struct file *fget_light(unsigned int fd, int *fput_needed)
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{
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struct file *file;
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struct files_struct *files = current->files;
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*fput_needed = 0;
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if (atomic_read(&files->count) == 1) {
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file = fcheck_files(files, fd);
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if (file && (file->f_mode & FMODE_PATH))
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file = NULL;
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} else {
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rcu_read_lock();
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file = fcheck_files(files, fd);
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if (file) {
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if (!(file->f_mode & FMODE_PATH) &&
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atomic_long_inc_not_zero(&file->f_count))
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*fput_needed = 1;
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else
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/* Didn't get the reference, someone's freed */
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file = NULL;
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}
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rcu_read_unlock();
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}
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return file;
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}
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struct file *fget_raw_light(unsigned int fd, int *fput_needed)
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{
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struct file *file;
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struct files_struct *files = current->files;
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*fput_needed = 0;
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if (atomic_read(&files->count) == 1) {
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file = fcheck_files(files, fd);
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} else {
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rcu_read_lock();
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file = fcheck_files(files, fd);
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if (file) {
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if (atomic_long_inc_not_zero(&file->f_count))
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*fput_needed = 1;
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else
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/* Didn't get the reference, someone's freed */
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file = NULL;
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}
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rcu_read_unlock();
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}
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return file;
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}
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106
fs/file_table.c
106
fs/file_table.c
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@ -339,112 +339,6 @@ void __fput_sync(struct file *file)
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EXPORT_SYMBOL(fput);
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EXPORT_SYMBOL(fput);
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struct file *fget(unsigned int fd)
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{
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struct file *file;
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struct files_struct *files = current->files;
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rcu_read_lock();
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file = fcheck_files(files, fd);
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if (file) {
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/* File object ref couldn't be taken */
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if (file->f_mode & FMODE_PATH ||
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!atomic_long_inc_not_zero(&file->f_count))
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file = NULL;
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}
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rcu_read_unlock();
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return file;
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}
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EXPORT_SYMBOL(fget);
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struct file *fget_raw(unsigned int fd)
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{
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struct file *file;
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struct files_struct *files = current->files;
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rcu_read_lock();
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file = fcheck_files(files, fd);
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if (file) {
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/* File object ref couldn't be taken */
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if (!atomic_long_inc_not_zero(&file->f_count))
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file = NULL;
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}
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rcu_read_unlock();
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return file;
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}
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EXPORT_SYMBOL(fget_raw);
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/*
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* Lightweight file lookup - no refcnt increment if fd table isn't shared.
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*
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* You can use this instead of fget if you satisfy all of the following
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* conditions:
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* 1) You must call fput_light before exiting the syscall and returning control
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* to userspace (i.e. you cannot remember the returned struct file * after
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* returning to userspace).
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* 2) You must not call filp_close on the returned struct file * in between
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* calls to fget_light and fput_light.
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* 3) You must not clone the current task in between the calls to fget_light
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* and fput_light.
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*
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* The fput_needed flag returned by fget_light should be passed to the
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* corresponding fput_light.
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*/
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struct file *fget_light(unsigned int fd, int *fput_needed)
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{
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struct file *file;
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struct files_struct *files = current->files;
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*fput_needed = 0;
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if (atomic_read(&files->count) == 1) {
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file = fcheck_files(files, fd);
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if (file && (file->f_mode & FMODE_PATH))
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file = NULL;
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} else {
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rcu_read_lock();
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file = fcheck_files(files, fd);
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if (file) {
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if (!(file->f_mode & FMODE_PATH) &&
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atomic_long_inc_not_zero(&file->f_count))
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*fput_needed = 1;
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else
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/* Didn't get the reference, someone's freed */
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file = NULL;
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}
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rcu_read_unlock();
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}
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return file;
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}
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struct file *fget_raw_light(unsigned int fd, int *fput_needed)
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{
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struct file *file;
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struct files_struct *files = current->files;
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*fput_needed = 0;
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if (atomic_read(&files->count) == 1) {
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file = fcheck_files(files, fd);
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} else {
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rcu_read_lock();
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file = fcheck_files(files, fd);
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if (file) {
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if (atomic_long_inc_not_zero(&file->f_count))
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*fput_needed = 1;
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else
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/* Didn't get the reference, someone's freed */
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file = NULL;
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}
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rcu_read_unlock();
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}
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return file;
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}
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void put_filp(struct file *file)
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void put_filp(struct file *file)
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{
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{
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if (atomic_long_dec_and_test(&file->f_count)) {
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if (atomic_long_dec_and_test(&file->f_count)) {
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