linux-toradex.git/fs/omfs/inode.c, branch v5.0

omfs: Implement show_options

2017-07-06T07:31:46+00:00

Implement the show_options superblock op for omfs as part of a bid to get
rid of s_options and generic_show_options() to make it easier to implement
a context-based mount where the mount options can be passed individually
over a file descriptor.

Note that the uid and gid should possibly be displayed relative to the
viewer's user namespace.

Signed-off-by: David Howells 
cc: Bob Copeland 
cc: linux-karma-devel@lists.sourceforge.net
Signed-off-by: Al Viro

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

fs: Replace CURRENT_TIME with current_time() for inode timestamps

2016-09-28T01:06:21+00:00

CURRENT_TIME macro is not appropriate for filesystems as it
doesn't use the right granularity for filesystem timestamps.
Use current_time() instead.

CURRENT_TIME is also not y2038 safe.

This is also in preparation for the patch that transitions
vfs timestamps to use 64 bit time and hence make them
y2038 safe. As part of the effort current_time() will be
extended to do range checks. Hence, it is necessary for all
file system timestamps to use current_time(). Also,
current_time() will be transitioned along with vfs to be
y2038 safe.

Note that whenever a single call to current_time() is used
to change timestamps in different inodes, it is because they
share the same time granularity.

Signed-off-by: Deepa Dinamani 
Reviewed-by: Arnd Bergmann 
Acked-by: Felipe Balbi 
Acked-by: Steven Whitehouse 
Acked-by: Ryusuke Konishi 
Acked-by: David Sterba 
Signed-off-by: Al Viro

omfs: fix sign confusion for bitmap loop counter

2015-05-29T01:25:19+00:00

The count variable is used to iterate down to (below) zero from the size
of the bitmap and handle the one-filling the remainder of the last
partial bitmap block.  The loop conditional expects count to be signed
in order to detect when the final block is processed, after which count
goes negative.

Unfortunately, a recent change made this unsigned along with some other
related fields.  The result of is this is that during mount,
omfs_get_imap will overrun the bitmap array and corrupt memory unless
number of blocks happens to be a multiple of 8 * blocksize.

Fix by changing count back to signed: it is guaranteed to fit in an s32
without overflow due to an enforced limit on the number of blocks in the
filesystem.

Signed-off-by: Bob Copeland 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

omfs: set error return when d_make_root() fails

2015-05-29T01:25:18+00:00

A static checker found the following issue in the error path for
omfs_fill_super:

    fs/omfs/inode.c:552 omfs_fill_super()
    warn: missing error code here? 'd_make_root()' failed. 'ret' = '0'

Fix by returning -ENOMEM in this case.

Signed-off-by: Bob Copeland 
Reported-by: Dan Carpenter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs, omfs: add NULL terminator in the end up the token list

2015-05-29T01:25:18+00:00

match_token() expects a NULL terminator at the end of the token list so
that it would know where to stop.  Not having one causes it to overrun
to invalid memory.

In practice, passing a mount option that omfs didn't recognize would
sometimes panic the system.

Signed-off-by: Sasha Levin 
Signed-off-by: Bob Copeland 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

FS/OMFS: block number sanity check during fill_super operation

2014-10-14T00:18:22+00:00

This patch defines maximum block number to 2^31.  It also converts
bitmap_size and array_size to unsigned int in omfs_get_imap

Signed-off-by: Fabian Frederick 
Suggested-by: Linus Torvalds 
Suggested-by: Bob Copeland 
Acked-by: Bob Copeland 
Tested-by: Bob Copeland 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs/omfs/inode.c: replace count*size kzalloc by kcalloc

2014-08-08T22:57:25+00:00

kcalloc manages count*sizeof overflow.

Signed-off-by: Fabian Frederick 
Acked-by: Bob Copeland 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm + fs: store shadow entries in page cache

2014-04-03T23:21:01+00:00

Reclaim will be leaving shadow entries in the page cache radix tree upon
evicting the real page.  As those pages are found from the LRU, an
iput() can lead to the inode being freed concurrently.  At this point,
reclaim must no longer install shadow pages because the inode freeing
code needs to ensure the page tree is really empty.

Add an address_space flag, AS_EXITING, that the inode freeing code sets
under the tree lock before doing the final truncate.  Reclaim will check
for this flag before installing shadow pages.

Signed-off-by: Johannes Weiner 
Reviewed-by: Rik van Riel 
Reviewed-by: Minchan Kim 
Cc: Andrea Arcangeli 
Cc: Bob Liu 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Greg Thelen 
Cc: Hugh Dickins 
Cc: Jan Kara 
Cc: KOSAKI Motohiro 
Cc: Luigi Semenzato 
Cc: Mel Gorman 
Cc: Metin Doslu 
Cc: Michel Lespinasse 
Cc: Ozgun Erdogan 
Cc: Peter Zijlstra 
Cc: Roman Gushchin 
Cc: Ryan Mallon 
Cc: Tejun Heo 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs: Limit sys_mount to only request filesystem modules.

2013-03-04T03:36:31+00:00

Modify the request_module to prefix the file system type with "fs-"
and add aliases to all of the filesystems that can be built as modules
to match.

A common practice is to build all of the kernel code and leave code
that is not commonly needed as modules, with the result that many
users are exposed to any bug anywhere in the kernel.

Looking for filesystems with a fs- prefix limits the pool of possible
modules that can be loaded by mount to just filesystems trivially
making things safer with no real cost.

Using aliases means user space can control the policy of which
filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
with blacklist and alias directives.  Allowing simple, safe,
well understood work-arounds to known problematic software.

This also addresses a rare but unfortunate problem where the filesystem
name is not the same as it's module name and module auto-loading
would not work.  While writing this patch I saw a handful of such
cases.  The most significant being autofs that lives in the module
autofs4.

This is relevant to user namespaces because we can reach the request
module in get_fs_type() without having any special permissions, and
people get uncomfortable when a user specified string (in this case
the filesystem type) goes all of the way to request_module.

After having looked at this issue I don't think there is any
particular reason to perform any filtering or permission checks beyond
making it clear in the module request that we want a filesystem
module.  The common pattern in the kernel is to call request_module()
without regards to the users permissions.  In general all a filesystem
module does once loaded is call register_filesystem() and go to sleep.
Which means there is not much attack surface exposed by loading a
filesytem module unless the filesystem is mounted.  In a user
namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
which most filesystems do not set today.

Acked-by: Serge Hallyn 
Acked-by: Kees Cook 
Reported-by: Kees Cook 
Signed-off-by: "Eric W. Biederman"