linux-stable.git/fs/file_table.c, branch v4.17

vfs: remove unused hardirq.h

2017-12-07T19:23:30+00:00

Preempt counter APIs have been split out, currently, hardirq.h just
includes irq_enter/exit APIs which are not used by vfs at all.

So, remove the unused hardirq.h.

Signed-off-by: Yang Shi 
Cc: Alexander Viro 
Signed-off-by: Al Viro

fs, mm: account filp cache to kmemcg

2017-11-16T02:21:04+00:00

The allocations from filp cache can be directly triggered by userspace
applications.  A buggy application can consume a significant amount of
unaccounted system memory.  Though we have not noticed such buggy
applications in our production but upon close inspection, we found that
a lot of machines spend very significant amount of memory on these
caches.

One way to limit allocations from filp cache is to set system level
limit of maximum number of open files.  However this limit is shared
between different users on the system and one user can hog this
resource.  To cater that, we can charge filp to kmemcg and set the
maximum limit very high and let the memory limit of each user limit the
number of files they can open and indirectly limiting their allocations
from filp cache.

One side effect of this change is that it will allow _sysctl() to return
ENOMEM and the man page of _sysctl() does not specify that.  However the
man page also discourages to use _sysctl() at all.

Link: http://lkml.kernel.org/r/20171011190359.34926-1-shakeelb@google.com
Signed-off-by: Shakeel Butt 
Cc: Alexander Viro 
Cc: Vladimir Davydov 
Cc: Michal Hocko 
Cc: Greg Thelen 
Cc: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ima: call ima_file_free() prior to calling fasync

2017-11-08T20:16:36+00:00

The file hash is calculated and written out as an xattr after
calling fasync().  In order for the file data and metadata to be
written out to disk at the same time, this patch calculates the
file hash and stores it as an xattr before calling fasync.

Signed-off-by: Mimi Zohar

fput: Don't reinvent the wheel but use existing llist API

2017-08-28T04:50:23+00:00

Although llist provides proper APIs, they are not used. Make them used.

Signed-off-by: Byungchul Park 
Reviewed-by: Oleg Nesterov 
Signed-off-by: Al Viro

fs: new infrastructure for writeback error handling and reporting

2017-07-06T11:02:25+00:00

Most filesystems currently use mapping_set_error and
filemap_check_errors for setting and reporting/clearing writeback errors
at the mapping level. filemap_check_errors is indirectly called from
most of the filemap_fdatawait_* functions and from
filemap_write_and_wait*. These functions are called from all sorts of
contexts to wait on writeback to finish -- e.g. mostly in fsync, but
also in truncate calls, getattr, etc.

The non-fsync callers are problematic. We should be reporting writeback
errors during fsync, but many places spread over the tree clear out
errors before they can be properly reported, or report errors at
nonsensical times.

If I get -EIO on a stat() call, there is no reason for me to assume that
it is because some previous writeback failed. The fact that it also
clears out the error such that a subsequent fsync returns 0 is a bug,
and a nasty one since that's potentially silent data corruption.

This patch adds a small bit of new infrastructure for setting and
reporting errors during address_space writeback. While the above was my
original impetus for adding this, I think it's also the case that
current fsync semantics are just problematic for userland. Most
applications that call fsync do so to ensure that the data they wrote
has hit the backing store.

In the case where there are multiple writers to the file at the same
time, this is really hard to determine. The first one to call fsync will
see any stored error, and the rest get back 0. The processes with open
fds may not be associated with one another in any way. They could even
be in different containers, so ensuring coordination between all fsync
callers is not really an option.

One way to remedy this would be to track what file descriptor was used
to dirty the file, but that's rather cumbersome and would likely be
slow. However, there is a simpler way to improve the semantics here
without incurring too much overhead.

This set adds an errseq_t to struct address_space, and a corresponding
one is added to struct file. Writeback errors are recorded in the
mapping's errseq_t, and the one in struct file is used as the "since"
value.

This changes the semantics of the Linux fsync implementation such that
applications can now use it to determine whether there were any
writeback errors since fsync(fd) was last called (or since the file was
opened in the case of fsync having never been called).

Note that those writeback errors may have occurred when writing data
that was dirtied via an entirely different fd, but that's the case now
with the current mapping_set_error/filemap_check_error infrastructure.
This will at least prevent you from getting a false report of success.

The new behavior is still consistent with the POSIX spec, and is more
reliable for application developers. This patch just adds some basic
infrastructure for doing this, and ensures that the f_wb_err "cursor"
is properly set when a file is opened. Later patches will change the
existing code to use this new infrastructure for reporting errors at
fsync time.

Signed-off-by: Jeff Layton 
Reviewed-by: Jan Kara

sched/headers: Prepare to remove inclusion from

2017-03-02T07:42:31+00:00

Add #include  dependencies to all .c files rely on sched.h
doing that for them.

Note that even if the count where we need to add extra headers seems high,
it's still a net win, because  is included in over
2,200 files ...

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

constify alloc_file()

2016-12-06T00:01:16+00:00

Signed-off-by: Al Viro

fs, file table: reinit files_stat.max_files after deferred memory initialisation

2015-08-07T01:39:40+00:00

Dave Hansen reported the following;

	My laptop has been behaving strangely with 4.2-rc2.  Once I log
	in to my X session, I start getting all kinds of strange errors
	from applications and see this in my dmesg:

        	VFS: file-max limit 8192 reached

The problem is that the file-max is calculated before memory is fully
initialised and miscalculates how much memory the kernel is using.  This
patch recalculates file-max after deferred memory initialisation.  Note
that using memory hotplug infrastructure would not have avoided this
problem as the value is not recalculated after memory hot-add.

4.1:             files_stat.max_files = 6582781
4.2-rc2:         files_stat.max_files = 8192
4.2-rc2 patched: files_stat.max_files = 6562467

Small differences with the patch applied and 4.1 but not enough to matter.

Signed-off-by: Mel Gorman 
Reported-by: Dave Hansen 
Cc: Nicolai Stange 
Cc: Dave Hansen 
Cc: Alex Ng 
Cc: Fengguang Wu 
Cc: Peter Zijlstra (Intel) 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

remove the pointless include of lglock.h

2015-06-23T22:02:00+00:00

Signed-off-by: Al Viro

->aio_read and ->aio_write removed

2015-04-12T02:29:43+00:00

no remaining users

Signed-off-by: Al Viro