linux.git/fs/fat, branch v4.6

fat: add config option to set UTF-8 mount option by default

2016-03-22T22:36:02+00:00

FAT has long supported its own default file name encoding config
setting, separate from CONFIG_NLS_DEFAULT.

However, if UTF-8 encoded file names are desired FAT character set
should not be set to utf8 since this would make file names case
sensitive even if case insensitive matching is requested.  Instead,
"utf8" mount options should be provided to enable UTF-8 file names in
FAT file system.

Unfortunately, there was no possibility to set the default value of this
option so on UTF-8 system "utf8" mount option had to be added manually
to most FAT mounts.

This patch adds config option to set such default value.

Signed-off-by: Maciej S. Szmigiero 
Acked-by: OGAWA Hirofumi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

wrappers for ->i_mutex access

2016-01-22T23:04:28+00:00

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.

Signed-off-by: Al Viro

fat: constify fatent_operations structures

2016-01-21T01:09:18+00:00

The fatent_operations structures are never modified, so declare them as
const.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall 
Acked-by: OGAWA Hirofumi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fat: permit to return phy block number by fibmap in fallocated region

2016-01-21T01:09:18+00:00

Make the fibmap call return the proper physical block number for any
offset request in the fallocated range.

Signed-off-by: Namjae Jeon 
Signed-off-by: Amit Sahrawat 
Cc: OGAWA Hirofumi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fat: skip cluster allocation on fallocated region

2016-01-21T01:09:18+00:00

Skip new cluster allocation after checking i_blocks limit in _fat_get_block,
because the blocks are already allocated in fallocated region.

Signed-off-by: Namjae Jeon 
Signed-off-by: Amit Sahrawat 
Cc: OGAWA Hirofumi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fat: add fat_fallocate operation

2016-01-21T01:09:18+00:00

Implement preallocation via the fallocate syscall on VFAT partitions.
This patch is based on an earlier patch of the same name which had some
issues detailed below and did not get accepted.  Refer
https://lkml.org/lkml/2007/12/22/130.

a) The preallocated space was not persistent when the
   FALLOC_FL_KEEP_SIZE flag was set.  It will deallocate cluster at evict
   time.

b) There was no need to zero out the clusters when the flag was set
   Instead of doing an expanding truncate, just allocate clusters and add
   them to the fat chain.  This reduces preallocation time.

Compatibility with windows:

There are no issues when FALLOC_FL_KEEP_SIZE is not set because it just
does an expanding truncate.  Thus reading from the preallocated area on
windows returns null until data is written to it.

When a file with preallocated area using the FALLOC_FL_KEEP_SIZE was
written to on windows, the windows driver freed-up the preallocated
clusters and allocated new clusters for the new data.  The freed up
clusters gets reflected in the free space available for the partition
which can be seen from the Volume properties.

The windows chkdsk tool also does not report any errors on a disk
containing files with preallocated space.

And there is also no issue using linux fat fsck.  because discard
preallocated clusters at repair time.

Signed-off-by: Namjae Jeon 
Signed-off-by: Amit Sahrawat 
Cc: OGAWA Hirofumi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fat: add simple validation for directory inode

2016-01-21T01:09:18+00:00

This detects simple corruption cases of directory, and tries to avoid
further damage to user data.

And performance impact of this validation should be very low, or not
measurable.

Signed-off-by: OGAWA Hirofumi 
Reported-by: Vegard Nossum 
Tested-by: Vegard Nossum 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fat: allow time_offset to be up to 24 hours

2016-01-21T01:09:18+00:00

Currently we limit values of time_offset mount option to be between -12
and 12 hours.  However e.g.  zone GMT+12 can have a DST correction on top
which makes the total time difference 13 hours.  Update the checks in
mount option parsing to allow offset of upto 24 hours to allow for unusual
cases.

Signed-off-by: Jan Kara 
Reported-by: Volker Kuhlmann 
Acked-by: OGAWA Hirofumi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kmemcg: account certain kmem allocations to memcg

2016-01-15T00:00:49+00:00

Mark those kmem allocations that are known to be easily triggered from
userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to
memcg.  For the list, see below:

 - threadinfo
 - task_struct
 - task_delay_info
 - pid
 - cred
 - mm_struct
 - vm_area_struct and vm_region (nommu)
 - anon_vma and anon_vma_chain
 - signal_struct
 - sighand_struct
 - fs_struct
 - files_struct
 - fdtable and fdtable->full_fds_bits
 - dentry and external_name
 - inode for all filesystems. This is the most tedious part, because
   most filesystems overwrite the alloc_inode method.

The list is far from complete, so feel free to add more objects.
Nevertheless, it should be close to "account everything" approach and
keep most workloads within bounds.  Malevolent users will be able to
breach the limit, but this was possible even with the former "account
everything" approach (simply because it did not account everything in
fact).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Vladimir Davydov 
Acked-by: Johannes Weiner 
Acked-by: Michal Hocko 
Cc: Tejun Heo 
Cc: Greg Thelen 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fat: fix fake_offset handling on error path

2015-11-21T00:17:32+00:00

For the root directory, .  and ..  are faked (using dir_emit_dots()) and
ctx->pos is reset from 2 to 0.

A corrupted root directory could cause fat_get_entry() to fail, but
->iterate() (fat_readdir()) reports progress to the VFS (with ctx->pos
rewound to 0), so any following calls to ->iterate() continue to return
the same entries again and again.

The result is that userspace will never see the end of the directory,
causing e.g.  'ls' to hang in a getdents() loop.

[hirofumi@mail.parknet.co.jp: cleanup and make sure to correct fake_offset]
Reported-by: Vegard Nossum 
Tested-by: Vegard Nossum 
Signed-off-by: Richard Weinberger 
Signed-off-by: OGAWA Hirofumi 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds