1. 17 Jul, 2017 1 commit
• VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb) · bc98a42c
David Howells authored
```Firstly by applying the following with coccinelle's spatch:

@@ expression SB; @@
-SB->s_flags & MS_RDONLY
+sb_rdonly(SB)

to effect the conversion to sb_rdonly(sb), then by applying:

@@ expression A, SB; @@
(
-(!sb_rdonly(SB)) && A
+!sb_rdonly(SB) && A
|
-A != (sb_rdonly(SB))
+A != sb_rdonly(SB)
|
-A == (sb_rdonly(SB))
+A == sb_rdonly(SB)
|
-!(sb_rdonly(SB))
+!sb_rdonly(SB)
|
-A && (sb_rdonly(SB))
+A && sb_rdonly(SB)
|
-A || (sb_rdonly(SB))
+A || sb_rdonly(SB)
|
-(sb_rdonly(SB)) != A
+sb_rdonly(SB) != A
|
-(sb_rdonly(SB)) == A
+sb_rdonly(SB) == A
|
-(sb_rdonly(SB)) && A
+sb_rdonly(SB) && A
|
-(sb_rdonly(SB)) || A
+sb_rdonly(SB) || A
)

@@ expression A, B, SB; @@
(
-(sb_rdonly(SB)) ? 1 : 0
+sb_rdonly(SB)
|
-(sb_rdonly(SB)) ? A : B
+sb_rdonly(SB) ? A : B
)

to remove left over excess bracketage and finally by applying:

@@ expression A, SB; @@
(
-(A & MS_RDONLY) != sb_rdonly(SB)
+(bool)(A & MS_RDONLY) != sb_rdonly(SB)
|
-(A & MS_RDONLY) == sb_rdonly(SB)
+(bool)(A & MS_RDONLY) == sb_rdonly(SB)
)

to make comparisons against the result of sb_rdonly() (which is a bool)
work correctly.
Signed-off-by: David Howells <dhowells@redhat.com>```
2. 07 Jul, 2017 1 commit
• gfs2: Fix glock rhashtable rcu bug · 961ae1d8
Andreas Gruenbacher authored
```Before commit 88ffbf3e "GFS2: Use resizable hash table for glocks",
glocks were freed via call_rcu to allow reading the glock hashtable
locklessly using rcu.  This was then changed to free glocks immediately,
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Cc: stable@vger.kernel.org # 4.3+```
3. 06 Jul, 2017 2 commits
• buffer: set errors in mapping at the time that the error occurs · 87354e5d
Jeff Layton authored
```I noticed on xfs that I could still sometimes get back an error on fsync
on a fd that was opened after the error condition had been cleared.

The problem is that the buffer code sets the write_io_error flag and
then later checks that flag to set the error in the mapping. That flag
perisists for quite a while however. If the file is later opened with
O_TRUNC, the buffers will then be invalidated and the mapping's error
set such that a subsequent fsync will return error. I think this is
incorrect, as there was no writeback between the open and fsync.

Add a new mark_buffer_write_io_error operation that sets the flag and
the error in the mapping at the same time. Replace all calls to
set_buffer_write_io_error with mark_buffer_write_io_error, and remove
the places that check this flag in order to set the error in the
mapping.

This sets the error in the mapping earlier, at the time that it's first
detected.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>```
• VFS: Provide empty name qstr · cdf01226
David Howells authored
```Provide an empty name (ie. "") qstr for general use.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>```
4. 05 Jul, 2017 5 commits
• GFS2: constify attribute_group structures. · 29695254
```attribute_groups are not supposed to change at runtime. All functions
working with attribute_groups provided by <linux/sysfs.h> work with const
attribute_group. So mark the non-const structs as const.

File size before:
text	   data	    bss	    dec	    hex	filename
5259	   1344	      8	   6611	   19d3	fs/gfs2/sys.o

text	   data	    bss	    dec	    hex	filename
5371	   1216	      8	   6595	   19c3	fs/gfs2/sys.o
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
• gfs2: gfs2_create_inode: Keep glock across iput · e0b62e21
Andreas Gruenbacher authored
```On failure, keep the inode glock across the final iput of the new inode
so that gfs2_evict_inode doesn't have to re-acquire the glock.  That
way, gfs2_evict_inode won't need to revalidate the block type.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
• gfs2: Clean up glock work enqueuing · 6b0c7440
Andreas Gruenbacher authored
```This patch adds a standardized queueing mechanism for glock work
with spin_lock protection to prevent races.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
• gfs2: Protect gl->gl_object by spin lock · 6f6597ba
Andreas Gruenbacher authored
```Put all remaining accesses to gl->gl_object under the
gl->gl_lockref.lock spinlock to prevent races.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
• gfs2: Get rid of flush_delayed_work in gfs2_evict_inode · 4fd1a579
Andreas Gruenbacher authored
```So far, gfs2_evict_inode clears gl->gl_object and then flushes the glock
work queue to make sure that inode glops which dereference gl->gl_object
have finished running before the inode is destroyed.  However, flushing
the work queue may do more work than needed, and in particular, it may
call into DLM, which we want to avoid here.  Use a bit lock
(GIF_GLOP_PENDING) to synchronize between the inode glops and
gfs2_evict_inode instead to get rid of the flushing.

In addition, flush the work queues of existing glocks before reusing
them for new inodes to get those glocks into a known state: the glock
state engine currently doesn't handle glock re-appropriation correctly.
(We may be able to fix the glock state engine instead later.)

Based on a patch by Steven Whitehouse <swhiteho@redhat.com>.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
5. 20 Jun, 2017 1 commit
6. 12 Jun, 2017 2 commits
7. 09 Jun, 2017 2 commits
• block: switch bios to blk_status_t · 4e4cbee9
Christoph Hellwig authored
```Replace bi_error with a new bi_status to allow for a clear conversion.
Note that device mapper overloaded bi_error with a private value, which
we'll have to keep arround at least for now and thus propagate to a
proper blk_status_t value.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>```
• gfs2: remove the unused sd_log_error field · f729b66f
Christoph Hellwig authored
```Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@fb.com>```
8. 05 Jun, 2017 1 commit
• fs: switch ->s_uuid to uuid_t · 85787090
Christoph Hellwig authored
```For some file systems we still memcpy into it, but in various places this
already allows us to use the proper uuid helpers.  More to come..
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> (Changes to IMA/EVM)
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>```
9. 24 May, 2017 1 commit
• gfs2: Make flush bios explicitely sync · 0f0b9b63
Jan Kara authored
```Commit b685d3d6 "block: treat REQ_FUA and REQ_PREFLUSH as
synchronous" removed REQ_SYNC flag from WRITE_{FUA|PREFLUSH|...}
definitions.  generic_make_request_checks() however strips REQ_FUA and
REQ_PREFLUSH flags from a bio when the storage doesn't report volatile
write cache and thus write effectively becomes asynchronous which can

Fix the problem by making sure all bios which are synchronous are
properly marked with REQ_SYNC.

Fixes: b685d3d6
CC: Steven Whitehouse <swhiteho@redhat.com>
CC: cluster-devel@redhat.com
CC: stable@vger.kernel.org
Acked-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>```
10. 09 May, 2017 1 commit
• gfs2: replace CURRENT_TIME with current_time · b32c8c76
Stephen Rothwell authored
```Link: http://lkml.kernel.org/r/20170420161852.0492bc3f@canb.auug.org.auSigned-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>```
11. 05 May, 2017 1 commit
• GFS2: Allow glocks to be unlocked after withdraw · ed17545d
Bob Peterson authored
```This bug fixes a regression introduced by patch 0d1c7ae9.

The intent of the patch was to stop promoting glocks after a
file system is withdrawn due to a variety of errors, because doing
so results in a BUG(). (You should be able to unmount after a
withdraw rather than having the kernel panic.)

Unfortunately, it also stopped demotions, so glocks could not be
unlocked after withdraw, which means the unmount would hang.

This patch allows function do_xmote to demote locks to an
unlocked state after a withdraw, but not promote them.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
12. 20 Apr, 2017 2 commits
• fs: Remove SB_I_DYNBDI flag · c1844d53
Jan Kara authored
```Now that all bdi structures filesystems use are properly refcounted, we
can remove the SB_I_DYNBDI flag.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>```
• gfs2: Convert to properly refcounting bdi · 95fe66de
Jan Kara authored
```Similarly to set_bdev_super() GFS2 just used block device reference to
bdi. Convert it to properly getting bdi reference. The reference will
get automatically dropped on superblock destruction.

CC: Steven Whitehouse <swhiteho@redhat.com>
CC: Bob Peterson <rpeterso@redhat.com>
CC: cluster-devel@redhat.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>```
13. 19 Apr, 2017 1 commit
• GFS2: Non-recursive delete · d552a2b9
Bob Peterson authored
```Implement truncate/delete as a non-recursive algorithm. The older
algorithm was implemented with recursion to strip off each layer
at a time (going by height, starting with the maximum height.
This version tries to do the same thing but without recursion,
and without needing to allocate new structures or lists in memory.

For example, say you want to truncate a very large file to 1 byte,
and its end-of-file metapath is: 0.505.463.428. The starting
metapath would be 0.0.0.0. Since it's a truncate to non-zero, it
needs to preserve that byte, and all metadata pointing to it.
So it would start at 0.0.0.0, look up all its metadata buffers,
then free all data blocks pointed to at the highest level.
After that buffer is "swept", it moves on to 0.0.0.1, then
0.0.0.2, etc., reading in buffers and sweeping them clean.
When it gets to the end of the 0.0.0 metadata buffer (for 4K
blocks the last valid one is 0.0.0.508), it backs up to the
previous height and starts working on 0.0.1.0, then 0.0.1.1,
and so forth. After it reaches the end and sweeps 0.0.1.508,
it continues with 0.0.2.0, and so on. When that height is
exhausted, and it reaches 0.0.508.508 it backs up another level,
to 0.1.0.0, then 0.1.0.1, through 0.1.0.508. So it has to keep
marching backwards and forwards through the metadata until it's
all swept clean. Once it has all the data blocks freed, it
lowers the strip height, and begins the process all over again,
but with one less height. This time it sweeps 0.0.0 through
0.505.463. When that's clean, it lowers the strip height again
and works to free 0.505. Eventually it strips the lowest height, 0.
For a delete or truncate to 0, all metadata for all heights of
0.0.0.0 would be freed. For a truncate to 1 byte, 0.0.0.0 would
be preserved.

This isn't much different from normal integer incrementing,
where an integer gets incremented from 0000 (0.0.0.0) to 3021
(3.0.2.1). So 0000 gets increments to 0001, 0002, up to 0009,
then on to 0010, 0011 up to 0099, then 0100 and so forth. It's
just that each "digit" goes from 0 to 508 (for a total of 509
pointers) rather than from 0 to 9.

Note that the dinode will only have 483 pointers due to the
dinode structure itself.

Also note: this is just an example. These numbers (509 and 483)
are based on a standard 4K block size. Smaller block sizes will
yield smaller numbers of indirect pointers accordingly.

The truncation process is accomplished with the help of two
major functions and a few helper functions.

Functions do_strip and recursive_scan are obsolete, so removed.

New function sweep_bh_for_rgrps cleans a buffer_head pointed to
by the given metapath and height. By cleaning, I mean it frees
all blocks starting at the offset passed in metapath. It starts
at the first block in the buffer pointed to by the metapath and
identifies its resource group (rgrp). From there it frees all
subsequent block pointers that lie within that rgrp. If it's
already inside a transaction, it stays within it as long as it
can. In other words, it doesn't close a transaction until it knows
it's freed what it can from the resource group. In this way,
multiple buffers may be cleaned in a single transaction, as long
as those blocks in the buffer all lie within the same rgrp.

If it's not in a transaction, it starts one. If the buffer_head
has references to blocks within multiple rgrps, it frees all the
blocks inside the first rgrp it finds, then closes the
transaction. Then it repeats the cycle: identifies the next
unfreed block, uses it to find its rgrp, then starts a new
transaction for that set. It repeats this process repeatedly
until the buffer_head contains no more references to any blocks
past the given metapath.

Function trunc_dealloc has been reworked into a finite state
automaton. It has basically 3 active states:
DEALLOC_MP_FULL, DEALLOC_MP_LOWER, and DEALLOC_FILL_MP:

The DEALLOC_MP_FULL state implies the metapath has a full set
of buffers out to the "shrink height", and therefore, it can
call function sweep_bh_for_rgrps to free the blocks within the
highest height of the metapath. If it's just swept the lowest
level (or an error has occurred) the state machine is ended.
Otherwise it proceeds to the DEALLOC_MP_LOWER state.

The DEALLOC_MP_LOWER state implies we are finished with a given
buffer_head, which may now be released, and therefore we are
then missing some buffer information from the metapath. So we
need to find more buffers to read in. In most cases, this is
just a matter of releasing the buffer_head and moving to the
next pointer from the previous height, so it may be read in and
swept as well. If it can't find another non-null pointer to
process, it checks whether it's reached the end of a height
and needs to lower the strip height, or whether it still needs
move forward through the previous height's metadata. In this
state, all zero-pointers are skipped. From this state, it can
only loop around (once more backing up another height) or,
once a valid metapath is found (one that has non-zero
pointers), proceed to state DEALLOC_FILL_MP.

The DEALLOC_FILL_MP state implies that we have a metapath
but not all its buffers are read in. So we must proceed to read
in buffer_heads until the metapath has a valid buffer for every
height. If the previous state backed us up 3 heights, we may
need to read in a buffer, increment the height, then repeat the
process until buffers have been read in for all required heights.
If it's successful reading a buffer, and it's at the highest
height we need, it proceeds back to the DEALLOC_MP_FULL state.
If it's unable to fill in a buffer, (encounters a hole, etc.)
it tries to find another non-zero block pointer. If they're all
zero, it lowers the height and returns to the DEALLOC_MP_LOWER
state. If it finds a good non-null pointer, it loops around and
reads it in, while keeping the metapath in lock-step with the
pointers it examines.

The state machine runs until the truncation request is
satisfied. Then any transactions are ended, the quota and
statfs data are updated, and the function is complete.

Helper function metaptr1 was introduced to be an easy way to
determine the start of a buffer_head's indirect pointers.

Helper function lookup_mp_height was introduced to find a
metapath index and read in the buffer that corresponds to it.
In this way, function lookup_metapath becomes a simple loop to
call it for every height.

Helper function fillup_metapath is similar to lookup_metapath
except it can do partial lookups. If the state machine
backed up multiple levels (like 2999 wrapping to 3000) it
needs to find out the next starting point and start issuing

Helper function hptrs is a shortcut to determine how many
pointers should be expected in a buffer. Height 0 is the dinode
which has fewer pointers than the others.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
14. 05 Apr, 2017 1 commit
• gfs2: Re-enable fallocate for the rindex · d4d7fc12
Andrew Price authored
```Commit 86066914 "gfs2: Don't support
fallocate on jdata files" removed the ability of gfs2_grow to reserve
space at the end of the rindex, which could prevent a second gfs2_grow
from succeeding if the fs is full. Allow fallocate to work on the rindex
once again.
Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
15. 03 Apr, 2017 2 commits
• Revert "GFS2: Wait for iopen glock dequeues" · d4da3198
Andreas Gruenbacher authored
```Revert commit 86d067a7: it turns out
that waiting for iopen glock dequeues here isn't needed anymore because
the bugs that commit was meant to fix have been fixed otherwise.

In addition, we want to avoid waiting on glocks in gfs2_evict_inode in
shrinker context because the shrinker may be invoked on behalf of DLM,
in which case calling into DLM again would deadlock.  This commit makes
the described scenario less likely without completely avoiding it; it's
still a step in the right direction, though.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
• gfs2: Switch to rhashtable_lookup_get_insert_fast · 0a52aba7
Andreas Gruenbacher authored
```Switch from rhashtable_lookup_insert_fast + rhashtable_lookup_fast to
rhashtable_lookup_get_insert_fast, which is cleaner and avoids an extra
rhashtable lookup.

At the same time, turn the retry loop in gfs2_glock_get into an infinite
loop.  The lookup or insert will eventually succeed, usually very fast,
but there is no reason to give up trying at a fixed number of
iterations.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
16. 16 Mar, 2017 5 commits
• GFS2: Temporarily zero i_no_addr when creating a dinode · cc963a11
Bob Peterson authored
```Before this patch i_no_addr was not initialized until after the
return from allocating its block. That meant the i_no_addr was
temporarily uninitialized storage. Ordinarily that's not a concern,
but if inplace_reserve can't find space, it can call try_rgrp_unlink
which references i_no_addr as a block to avoid. That can result in
unpredictable behavior. More importantly, the trace point in
gfs2_alloc_blocks references ip->i_no_addr before it is set, which
look like the new dinode block was assigned in the name of inode 0
rather than a random inode that's completely unrelated.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
• gfs2: Don't pack struct lm_lockname · 972b044e
Andreas Gruenbacher authored
```As per a suggestion by Linus, don't pack struct lm_lockname: we did that
because the struct is used as a rhashtable key, but packing tells the
compiler that the 64-bit fields in the struct may be unaligned, causing
it to generate worse code on some architectures.  Instead, rearrange the
fields in the struct so that there is no padding between fields, and
exclude any tail padding from the hash key size.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
• gfs2: Deduplicate gfs2_{glocks,glstats}_open · 92ecd73a
Andreas Gruenbacher authored
```Both functions are identical except for the seq_operations used.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
• gfs2: Replace rhashtable_walk_init with rhashtable_walk_enter · cc37a627
Andreas Gruenbacher authored
```Function rhashtable_walk_init is deprecated.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
• GFS2: Prevent BUG from occurring when normal Withdraws occur · 0d1c7ae9
Bob Peterson authored
```When the GFS2 file system withdraws due to metadata corruption, it
often has outstanding transactions in the journal and delayed work
queued for its glocks. This patch adds some new checks for a
withdrawn file system before proceeding with operations that would
obviously cause a BUG() to be triggered. That allows GFS2 to be
safely unmounted rather than cause the system to go down.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
17. 15 Mar, 2017 1 commit
• gfs2: Avoid alignment hole in struct lm_lockname · 28ea06c4
Andreas Gruenbacher authored
```Commit 88ffbf3e switches to using rhashtables for glocks, hashing over
the entire struct lm_lockname instead of its individual fields.  On some
architectures, struct lm_lockname contains a hole of uninitialized
memory due to alignment rules, which now leads to incorrect hash values.
Get rid of that hole.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
CC: <stable@vger.kernel.org> #v4.3+```
18. 03 Mar, 2017 1 commit
• statx: Add a system call to make enhanced file info available · a528d35e
David Howells authored
```Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode.  This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included.  The
following have been included:

(1) Make the fields a consistent size on all arches and make them large.

(2) Spare space, request flags and information flags are provided for
future expansion.

(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).

(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).

This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].

(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).

(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].

Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr().  It could get
it from the kstat struct if it used vfs_xgetattr() instead.

(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).

(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].

(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].

(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...

(This requires a separate system call - I have an fsinfo() call idea
for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].

(Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].

(Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value.  These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).

(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].

(Deferred, probably to fsinfo.  Finding out if there's an ACL or
seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

int ret = statx(int dfd,
const char *filename,
unsigned int flags,
struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat().  There is no equivalent of lstat() as that can be
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.

(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.

(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem.  The resulting values should be considered
approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller.  The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat().  It should be noted that asking for

buffer points to the destination for the data.  This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

struct statx_timestamp {
__s64	tv_sec;
__s32	tv_nsec;
__s32	__reserved;
};

struct statx {
__u32	stx_blksize;
__u64	stx_attributes;
__u32	stx_uid;
__u32	stx_gid;
__u16	stx_mode;
__u16	__spare0[1];
__u64	stx_ino;
__u64	stx_size;
__u64	stx_blocks;
__u64	__spare1[1];
struct statx_timestamp	stx_atime;
struct statx_timestamp	stx_btime;
struct statx_timestamp	stx_ctime;
struct statx_timestamp	stx_mtime;
__u32	stx_rdev_major;
__u32	stx_rdev_minor;
__u32	stx_dev_major;
__u32	stx_dev_minor;
__u64	__spare2[14];
};

STATX_TYPE		Want/got stx_mode & S_IFMT
STATX_MODE		Want/got stx_mode & ~S_IFMT
STATX_UID		Want/got stx_uid
STATX_GID		Want/got stx_gid
STATX_ATIME		Want/got stx_atime{,_ns}
STATX_MTIME		Want/got stx_mtime{,_ns}
STATX_CTIME		Want/got stx_ctime{,_ns}
STATX_INO		Want/got stx_ino
STATX_SIZE		Want/got stx_size
STATX_BLOCKS		Want/got stx_blocks
STATX_BASIC_STATS	[The stuff in the normal stat struct]
STATX_BTIME		Want/got stx_btime{,_ns}
STATX_ALL		[All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution.  Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does.  The following
attributes map to FS_*_FL flags and are the same numerical value:

STATX_ATTR_COMPRESSED		File is compressed by the fs
STATX_ATTR_IMMUTABLE		File is marked immutable
STATX_ATTR_APPEND		File is append-only
STATX_ATTR_NODUMP		File is not to be dumped
STATX_ATTR_ENCRYPTED		File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

STATX_ATTR_AUTOMOUNT		Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

(0) stx_dev_*, stx_blksize.

These are local system information and are always available.

(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.

These will be returned whether the caller asks for them or not.  The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.

If the caller didn't ask for them, then they may be approximated.  For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.

If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value.  In such a case, the returned
value will be a fabrication.

Note that there are instances where the type might not be valid, for
instance Windows reparse points.

(2) stx_rdev_*.

This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.

(3) stx_btime.

Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output.  Firstly, an NFS directory that crosses to
another FSID.  Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096            Blocks: 8          IO Block: 1048576  directory
Device: 00:26           Inode: 1703937     Links: 125
Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096            Blocks: 8          IO Block: 1048576  directory
Device: 00:27           Inode: 2           Links: 125
Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>```
19. 02 Mar, 2017 2 commits
• sched/headers: Prepare to move signal wakeup & sigpending methods from... · 174cd4b1
Ingo Molnar authored
```sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h>

Fix up affected files that include this signal functionality via sched.h.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>```
• sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> · 5b825c3a
Ingo Molnar authored
```Add #include <linux/cred.h> 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 <linux/sched.h> is included in over
2,200 files ...
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>```
20. 25 Feb, 2017 1 commit
• mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmf · 11bac800
Dave Jiang authored
```->fault(), ->page_mkwrite(), and ->pfn_mkwrite() calls do not need to
take a vma and vmf parameter when the vma already resides in vmf.

Remove the vma parameter to simplify things.

[arnd@arndb.de: fix ARM build]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>```
21. 23 Feb, 2017 1 commit
• gfs2: Add missing rcu locking for glock lookup · f38e5fb9
Andrew Price authored
```We must hold the rcu read lock across looking up glocks and trying to
bump their refcount to prevent the glocks from being freed in between.

Cc: <stable@vger.kernel.org> # 4.3+
Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
22. 17 Feb, 2017 1 commit
• gfs2: Use rhashtable walk interface in glock_hash_walk · 98687f42
Herbert Xu authored
```The function glock_hash_walk walks the rhashtable by hand.  This
is broken because if it catches the hash table in the middle of
a rehash, then it will miss entries.

This patch replaces the manual walk by using the rhashtable walk
interface.

Fixes: 88ffbf3e ("GFS2: Use resizable hash table for glocks")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>```
23. 16 Feb, 2017 1 commit
• rhashtable: Revert nested table changes. · bf3f14d6
David S. Miller authored
```This reverts commits:

6a254780
9dbbfb0a
40137906

It's too risky to put in this late in the release
cycle.  We'll put these changes into the next merge
Signed-off-by: David S. Miller <davem@davemloft.net>```
24. 14 Feb, 2017 1 commit
• gfs2: Use rhashtable walk interface in glock_hash_walk · 6a254780
Herbert Xu authored
```The function glock_hash_walk walks the rhashtable by hand.  This
is broken because if it catches the hash table in the middle of
a rehash, then it will miss entries.

This patch replaces the manual walk by using the rhashtable walk
interface.

Fixes: 88ffbf3e ("GFS2: Use resizable hash table for glocks")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>```
25. 03 Feb, 2017 1 commit
• gfs2: Make gfs2_write_full_page static · c548a1c1
Andrew Price authored
```It only gets called from aops.c and doesn't appear in any headers.
Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>```
26. 02 Feb, 2017 1 commit
• block: Use pointer to backing_dev_info from request_queue · dc3b17cc
Jan Kara authored
```We will want to have struct backing_dev_info allocated separately from
struct request_queue. As the first step add pointer to backing_dev_info
to request_queue and convert all users touching it. No functional
changes in this patch.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>```