linux-stable.git/fs/file_table.c, branch v3.12

nfsd regression since delayed fput()

2013-10-20T12:44:39+00:00

Background: nfsd v[23] had throughput regression since delayed fput
went in; every read or write ends up doing fput() and we get a pair
of extra context switches out of that (plus quite a bit of work
in queue_work itselfi, apparently).  Use of schedule_delayed_work()
gives it a chance to accumulate a bit before we do __fput() on all
of them.  I'm not too happy about that solution, but... on at least
one real-world setup it reverts about 10% throughput loss we got from
switch to delayed fput.

Signed-off-by: Al Viro

fs/file_table.c:fput(): make comment more truthful

2013-09-11T22:59:01+00:00

Cc: "Eric W. Biederman" 
Cc: Andrey Vagin 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

only regular files with FMODE_WRITE need to be on s_files

2013-09-04T02:50:28+00:00

Signed-off-by: Al Viro

fput: turn "list_head delayed_fput_list" into llist_head

2013-07-13T09:29:10+00:00

fput() and delayed_fput() can use llist and avoid the locking.

This is unlikely path, it is not that this change can improve
the performance, but this way the code looks simpler.

Signed-off-by: Oleg Nesterov 
Suggested-by: Andrew Morton 
Cc: Al Viro 
Cc: Andrey Vagin 
Cc: "Eric W. Biederman" 
Cc: David Howells 
Cc: Huang Ying 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Al Viro

fs/file_table.c:fput(): add comment

2013-07-13T09:27:42+00:00

A missed update to "fput: task_work_add() can fail if the caller has
passed exit_task_work()".

Cc: "Eric W. Biederman" 
Cc: Al Viro 
Cc: Andrey Vagin 
Cc: David Howells 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Al Viro

Replace a bunch of file->dentry->d_inode refs with file_inode()

2013-06-29T08:57:13+00:00

Replace a bunch of file->dentry->d_inode refs with file_inode().

In __fput(), use file->f_inode instead so as not to be affected by any tricks
that file_inode() might grow.

Signed-off-by: David Howells 
Signed-off-by: Al Viro

fput: task_work_add() can fail if the caller has passed exit_task_work()

2013-06-15T01:39:08+00:00

fput() assumes that it can't be called after exit_task_work() but
this is not true, for example free_ipc_ns()->shm_destroy() can do
this. In this case fput() silently leaks the file.

Change it to fallback to delayed_fput_work if task_work_add() fails.
The patch looks complicated but it is not, it changes the code from

	if (PF_KTHREAD) {
		schedule_work(...);
		return;
	}
	task_work_add(...)

to
	if (!PF_KTHREAD) {
		if (!task_work_add(...))
			return;
		/* fallback */
	}
	schedule_work(...);

As for shm_destroy() in particular, we could make another fix but I
think this change makes sense anyway. There could be another similar
user, it is not safe to assume that task_work_add() can't fail.

Reported-by: Andrey Vagin 
Signed-off-by: Oleg Nesterov 
Signed-off-by: Al Viro

cache the value of file_inode() in struct file

2013-03-02T00:48:30+00:00

Note that this thing does *not* contribute to inode refcount;
it's pinned down by dentry.

Signed-off-by: Al Viro

fs: Preserve error code in get_empty_filp(), part 2

2013-02-23T04:31:32+00:00

Allocating a file structure in function get_empty_filp() might fail because
of several reasons:
 - not enough memory for file structures
 - operation is not allowed
 - user is over its limit

Currently the function returns NULL in all cases and we loose the exact
reason of the error. All callers of get_empty_filp() assume that the function
can fail with ENFILE only.

Return error through pointer. Change all callers to preserve this error code.

[AV: cleaned up a bit, carved the get_empty_filp() part out into a separate commit
(things remaining here deal with alloc_file()), removed pipe(2) behaviour change]

Signed-off-by: Anatol Pomozov 
Reviewed-by: "Theodore Ts'o" 
Signed-off-by: Al Viro

propagate error from get_empty_filp() to its callers

2013-02-23T04:31:32+00:00

Based on parts from Anatol's patch (the rest is the next commit).

Signed-off-by: Al Viro