Commit Graph

47 Commits

Author SHA1 Message Date
Ryusuke Konishi 325020477a nilfs2: do not update log cursor for small change
Super blocks of nilfs are periodically overwritten in order to record
the recent log position.  This shortens recovery time after unclean
unmount, but the current implementation performs the update even for a
few blocks of change.  If the filesystem gets small changes slowly and
continually, super blocks may be updated excessively.

This moderates the issue by skipping update of log cursor if it does
not cross a segment boundary.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-07-23 10:02:11 +09:00
Jiro SEKIBA b2ac86e1a8 nilfs2: sync super blocks in turns
This will sync super blocks in turns instead of syncing duplicate
super blocks at the time.  This will help searching valid super root
when super block is written into disk before log is written, which is
happen when barrier-less block devices are unmounted uncleanly.  In
the situation, old super block likely points to valid log.

This patch introduces ns_sbwcount member to the nilfs object and adds
nilfs_sb_will_flip() function; ns_sbwcount counts how many times super
blocks write back to the disk.  And, nilfs_sb_will_flip() decides
whether flipping required or not based on the count of ns_sbwcount to
sync super blocks asymmetrically.

The following functions are also changed:

 - nilfs_prepare_super(): flips super blocks according to the
   argument.  The argument is calculated by nilfs_sb_will_flip()
   function.

 - nilfs_cleanup_super(): sets "clean" flag to both super blocks if
   they point to the same checkpoint.

To update both of super block information, caller of
nilfs_commit_super must set the information on both super blocks.

Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-07-23 10:02:11 +09:00
Jiro SEKIBA d26493b6f0 nilfs2: introduce nilfs_prepare_super
This function checks validity of super block pointers.
If first super block is invalid, it will swap the super blocks.
The function should be called before any super block information updates.
Caller must obtain nilfs->ns_sem.

Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-07-23 10:02:10 +09:00
Ryusuke Konishi 4762077c7b nilfs2: get rid of macros for segment summary information
This removes macros to test segment summary flags and redefines a few
relevant macros with inline functions.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-07-23 10:02:09 +09:00
Ryusuke Konishi 4e819509cb nilfs2: make nilfs_sc_*_ops static
This kills the following sparse warnings:

fs/nilfs2/segment.c:567:28: warning: symbol 'nilfs_sc_file_ops' was not declared. Should it be static?
fs/nilfs2/segment.c:617:28: warning: symbol 'nilfs_sc_dat_ops' was not declared. Should it be static?
fs/nilfs2/segment.c:625:28: warning: symbol 'nilfs_sc_dsync_ops' was not declared. Should it be static?

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-05-10 11:32:31 +09:00
Li Hong fdce895ea5 nilfs2: change sc_timer from a pointer to an embedded one in struct nilfs_sc_info
In nilfs_segctor_thread(), timer is a local variable allocated on stack. Its
address can't be set to sci->sc_timer and passed in several procedures.

It works now by chance, just because other procedures are called by
nilfs_segctor_thread() directly or indirectly and the stack hasn't been
deallocated yet.

Signed-off-by: Li Hong <lihong.hi@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-05-10 11:32:31 +09:00
Li Hong 154ac5a830 nilfs2: remove nilfs_segctor_init() in segment.c
There are only two lines of code in nilfs_segctor_init(). From a logic
design view, the first line 'sci->sc_seq_done = sci->sc_seq_request;'
should be put in nilfs_segctor_new(). Even in nilfs_segctor_new(),
this initialization is needless because sci is kzalloc-ed. So
nilfs_segctor_init() is only a wrap call to
nilfs_segctor_start_thread().

Signed-off-by: Li Hong <lihong.hi@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-05-10 11:32:31 +09:00
Ryusuke Konishi 50614bcf29 nilfs2: insert checkpoint number in segment summary header
This adds a field to record the latest checkpoint number in the
nilfs_segment_summary structure.  This will help to recover the latest
checkpoint number from logs on disk.  This field is intended for
crucial cases in which super blocks have lost pointer to the latest
log.

Even though this will change the disk format, both backward and
forward compatibility is preserved by a size field prepared in the
segment summary header.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-05-10 11:32:31 +09:00
Li Hong 41c88bd74d nilfs2: cleanup multi kmem_cache_{create,destroy} code
This cleanup patch gives several improvements:

 - Moving all kmem_cache_{create_destroy} calls into one place, which removes
 some small function calls, cleans up error check code and clarify the logic.

 - Mark all initial code in __init section.

 - Remove some very obvious comments.

 - Adjust some declarations.

 - Fix some space-tab issues.

Signed-off-by: Li Hong <lihong.hi@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-05-10 11:32:30 +09:00
Ryusuke Konishi aaed1d5bfa nilfs2: move out checksum routines to segment buffer code
This moves out checksum routines in log writer to segbuf.c for
cleanup.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-05-10 11:32:30 +09:00
Ryusuke Konishi 1e2b68bf28 nilfs2: move pointer to super root block into logs
This moves a pointer to buffer storing super root block to each log
buffer from nilfs_sc_info struct for simplicity.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-05-10 11:32:30 +09:00
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Ryusuke Konishi 110d735a0a nilfs2: fix hang-up of cleaner after log writer returned with error
According to the report from Andreas Beckmann (Message-ID:
<4BA54677.3090902@abeckmann.de>), nilfs in 2.6.33 kernel got stuck
after a disk full error.

This turned out to be a regression by log writer updates merged at
kernel 2.6.33.  nilfs_segctor_abort_construction, which is a cleanup
function for erroneous cases, was skipping writeback completion for
some logs.

This fixes the bug and would resolve the hang issue.

Reported-by: Andreas Beckmann <debian@abeckmann.de>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: stable <stable@kernel.org>                     [2.6.33.x]
2010-03-24 00:03:06 +09:00
Ryusuke Konishi 2d8428acae nilfs2: fix duplicate call to nilfs_segctor_cancel_freev
Andreas Beckmann gave me a report that nilfs logged the following
warnings when it got a disk full:

  nilfs_sufile_do_cancel_free: segment 0 must be clean
  nilfs_sufile_do_cancel_free: segment 1 must be clean

These arise from a duplicate call to nilfs_segctor_cancel_freev in an
error path of log writer.  This will fix the issue.

Reported-by: Andreas Beckmann <debian@abeckmann.de>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-03-22 14:41:07 +09:00
Ryusuke Konishi 7a65004bba nilfs2: fix various typos in comments
This fixes various typos I found in comments of nilfs2.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-03-14 10:29:51 +09:00
Ryusuke Konishi 9ccf56c138 nilfs2: fix function name typos in docbook comments
Fixes the following typos in docbook comments:

 nilfs_detroy_transaction_cache -> nilfs_destroy_transaction_cache
 nilfs_secgtor_start_timer -> nilfs_segctor_start_timer

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-03-14 10:29:50 +09:00
Ryusuke Konishi d1c6b72a72 nilfs2: move iterator to write log into segment buffer
This moves iterator to submit write requests for a series of logs into
segbuf.c, and hides nilfs_segbuf_write() and nilfs_segbuf_wait() in
the file.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-02-13 12:26:03 +09:00
Ryusuke Konishi e605f0a724 nilfs2: get rid of s_dirt flag use
This replaces s_dirt flag use in nilfs with a new flag added on the
nilfs object.  The s_dirt flag was used to indicate if
sop->write_super() should be called, however the current version of
nilfs does not use the callback.  Thus, it can be replaced with the
own flag.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Jiro SEKIBA <jir@unicus.jp>
2010-02-13 12:26:03 +09:00
Ryusuke Konishi dcd7618695 nilfs2: get rid of nilfs_segctor_req struct
This will clean up nilfs_segctor_req struct and the obscure request
argument passed among private methods of segment constructor.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-02-13 12:26:03 +09:00
Ryusuke Konishi fe5f171bb2 nilfs2: fix potential hang in nilfs_error on errors=remount-ro
nilfs_error() calls nilfs_detach_segment_constructor() if
errors=remount-ro option is specified, and this may lead to a hang due
to recursive locking of, for instance, nilfs->ns_segctor_sem and
others.

In this case, detaching segment constructor is not necessary because
read-only flag is set to the filesystem and further writes are
blocked.

This fixes the potential hang issue by removing the
nilfs_detach_segment_constructor() call from nilfs_error.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-02-13 12:26:03 +09:00
Jiro SEKIBA e902ec9906 nilfs2: issue discard request after cleaning segments
This adds a function to send discard requests for given array of
segment numbers, and calls the function when garbage collection
succeeded.

Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-02-13 12:26:02 +09:00
Ryusuke Konishi 3256a05531 nilfs2: fix potential leak of dirty data on umount
This fixes incorrect usage of nilfs_segctor_confirm() test function in
nilfs_segctor_destroy(); nilfs_segctor_confirm() returns zero if the
filesystem is not clean, so its use in nilfs_segctor_destroy() needs
inversion.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-01-31 14:57:31 +09:00
Ryusuke Konishi a694291a62 nilfs2: separate wait function from nilfs_segctor_write
This separates wait function for submitted logs from the write
function nilfs_segctor_write().  A new list of segment buffers
"sc_write_logs" is added to hold logs under writing, and double
buffering is partially applied to hide io latency.

At this point, the double buffering is disabled for blocksize <
pagesize because page dirty flag is turned off during write and dirty
buffers are not properly collected for pages crossing over segments.

To receive full benefit of the double buffering, further refinement is
needed to move the io wait outside the lock section of log writer.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-11-30 21:17:52 +09:00
Ryusuke Konishi e29df395bc nilfs2: add iterator for segment buffers
This adds a few iterator functions for segment buffers to make it easy
to handle multiple series of logs.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-11-30 21:06:35 +09:00
Ryusuke Konishi 9c965bac16 nilfs2: hide nilfs_write_info struct in segment buffer code
Hides nilfs_write_info struct and nilfs_segbuf_prepare_write function
in segbuf.c to simplify the interface of nilfs_segbuf_write function.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-11-30 21:06:35 +09:00
Ryusuke Konishi 9284ad2a90 nilfs2: relocate io status variables to segment buffer
This moves io status variables in nilfs_write_info struct to
nilfs_segment_buffer struct.

This is a preparation to hide nilfs_write_info in segment buffer code.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-11-30 21:05:57 +09:00
Ryusuke Konishi 0935db7477 nilfs2: use list_splice_tail or list_splice_tail_init
This applies list_splice_tail (or list_splice_tail_init) operation
instead of list_splice (or list_splice_init, respectively) to append a
new list to tail of an existing list.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-11-29 02:50:46 +09:00
Ryusuke Konishi 071ec54dd7 nilfs2: move routine to set segment usage into sufile
This adds nilfs_sufile_set_segment_usage() function in sufile to
replace direct access to the sufile metadata in log writer code.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-11-20 10:05:51 +09:00
Ryusuke Konishi 61a189e9c6 nilfs2: move routine marking segment usage dirty into sufile
This adds nilfs_sufile_mark_dirty() function in sufile to replace
nilfs_touch_segusage() function in log writer code.  This is a
preparation for the further cleanup which will move out low level
sufile operations in the log writer.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-11-20 10:05:51 +09:00
Ryusuke Konishi 3961f0e277 nilfs2: eliminate inlines to directly read/write inode of metadata files
Removes two inline functions: nilfs_mdt_read_inode_direct() and
nilfs_mdt_write_inode_direct().

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-11-20 10:05:48 +09:00
Ryusuke Konishi aeda7f6343 nilfs2: fix irregular checkpoint creation due to data flush
When nilfs flushes out dirty data to reduce memory pressure, creation
of checkpoints is wrongly postponed.  This bug causes irregular
checkpoint creation especially in small footprint systems.

To correct this issue, a timer for the checkpoint creation has to be
continued if a log writer does not create a checkpoint.

This will do the correction.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-11-03 12:32:03 +09:00
Jiro SEKIBA 1dfa27105a nilfs2: stop using periodic write_super callback
This removes nilfs_write_super and commit super block in nilfs
internal thread, instead of periodic write_super callback.

VFS layer calls ->write_super callback periodically.  However,
it looks like that calling back is ommited when disk I/O is busy.
And when cleanerd (nilfs GC) is runnig, disk I/O tend to be busy thus
nilfs superblock is not synchronized as nilfs designed.

To avoid it, syncing superblock by nilfs thread instead of pdflush.

Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-09-14 18:27:14 +09:00
Ryusuke Konishi a97778457f nilfs2: fix oops due to inconsistent state in page with discrete b-tree nodes
Andrea Gelmini gave me a report that a kernel oops hit on a nilfs
filesystem with a 1KB block size when doing rsync.

This turned out to be caused by an inconsistency of dirty state
between a page and its buffers storing b-tree node blocks.

If the page had multiple buffers split over multiple logs, and if the
logs were written at a time, a dirty flag remained in the page even
every dirty flag in the buffers was cleared.

This will fix the failure by dropping the dirty flag properly for
pages with the discrete multiple b-tree nodes.

Reported-by: Andrea Gelmini <andrea.gelmini@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: Andrea Gelmini <andrea.gelmini@gmail.com>
Cc: stable@kernel.org
2009-08-01 22:48:32 +09:00
Ryusuke Konishi 8227b29722 nilfs2: fix hang problem of log writer which occurs after write failures
Leandro Lucarella gave me a report that nilfs gets stuck after its
write function fails.

The problem turned out to be caused by bugs which leave writeback flag
on pages.  This fixes the problem by ensuring to clear the writeback
flag in error path.

Reported-by: Leandro Lucarella <llucax@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: stable@kernel.org
2009-07-05 10:44:20 +09:00
Ryusuke Konishi 0cfae3d879 nilfs2: remove unlikely directive causing mis-conversion of error code
The following error code handling in nilfs_segctor_write() function
wrongly converted negative error codes to a truth value (i.e. 1):

   err = unlikely(err) ? : res;

which originaly meant to be

   err = err ? : res;

This mis-conversion caused that write or sync functions receive the
unexpected error code.  This fixes the bug by removing the unlikely
directive.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: stable@kernel.org
2009-07-05 10:44:19 +09:00
Ryusuke Konishi 071cb4b819 nilfs2: eliminate removal list of segments
This will clean up the removal list of segments and the related
functions from segment.c and ioctl.c, which have hurt code
readability.

This elimination is applied by using nilfs_sufile_updatev() previously
introduced in the patch ("nilfs2: add sufile function that can modify
multiple segment usages").

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-06-10 23:41:09 +09:00
Ryusuke Konishi 4f6b828837 nilfs2: fix lock order reversal in nilfs_clean_segments ioctl
This is a companion patch to ("nilfs2: fix possible circular locking
for get information ioctls").

This corrects lock order reversal between mm->mmap_sem and
nilfs->ns_segctor_sem in nilfs_clean_segments() which was detected by
lockdep check:

 =======================================================
 [ INFO: possible circular locking dependency detected ]
 2.6.30-rc3-nilfs-00003-g360bdc1 #7
 -------------------------------------------------------
 mmap/5294 is trying to acquire lock:
  (&nilfs->ns_segctor_sem){++++.+}, at: [<d0d0e846>] nilfs_transaction_begin+0xb6/0x10c [nilfs2]

 but task is already holding lock:
  (&mm->mmap_sem){++++++}, at: [<c043700a>] do_page_fault+0x1d8/0x30a

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #1 (&mm->mmap_sem){++++++}:
        [<c01470a5>] __lock_acquire+0x1066/0x13b0
        [<c01474a9>] lock_acquire+0xba/0xdd
        [<c01836bc>] might_fault+0x68/0x88
        [<c023c61d>] copy_from_user+0x2a/0x111
        [<d0d120d0>] nilfs_ioctl_prepare_clean_segments+0x1d/0xf1 [nilfs2]
        [<d0d0e2aa>] nilfs_clean_segments+0x6d/0x1b9 [nilfs2]
        [<d0d11f68>] nilfs_ioctl+0x2ad/0x318 [nilfs2]
        [<c01a3be7>] vfs_ioctl+0x22/0x69
        [<c01a408e>] do_vfs_ioctl+0x460/0x499
        [<c01a4107>] sys_ioctl+0x40/0x5a
        [<c01031a4>] sysenter_do_call+0x12/0x38
        [<ffffffff>] 0xffffffff

 -> #0 (&nilfs->ns_segctor_sem){++++.+}:
        [<c0146e0b>] __lock_acquire+0xdcc/0x13b0
        [<c01474a9>] lock_acquire+0xba/0xdd
        [<c0433f1d>] down_read+0x2a/0x3e
        [<d0d0e846>] nilfs_transaction_begin+0xb6/0x10c [nilfs2]
        [<d0cfe0e5>] nilfs_page_mkwrite+0xe7/0x154 [nilfs2]
        [<c0183b0b>] __do_fault+0x165/0x376
        [<c01855cd>] handle_mm_fault+0x287/0x5d1
        [<c043712d>] do_page_fault+0x2fb/0x30a
        [<c0435462>] error_code+0x72/0x78
        [<ffffffff>] 0xffffffff

where nilfs_clean_segments() holds:

  nilfs->ns_segctor_sem -> copy_from_user()
                             --> page fault -> mm->mmap_sem

And, page fault path may hold:

  page fault -> mm->mmap_sem
         --> nilfs_page_mkwrite() -> nilfs->ns_segctor_sem

Even though nilfs_clean_segments() does not perform write access on
given user pages, it may cause deadlock because nilfs->ns_segctor_sem
is shared per device and mm->mmap_sem can be shared with other tasks.

To avoid this problem, this patch moves all calls of copy_from_user()
outside the nilfs->ns_segctor_sem lock in the ioctl.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-05-11 14:54:41 +09:00
Ryusuke Konishi e339ad31f5 nilfs2: introduce secondary super block
The former versions didn't have extra super blocks.  This improves the
weak point by introducing another super block at unused region in tail of
the partition.

This doesn't break disk format compatibility; older versions just ingore
the secondary super block, and new versions just recover it if it doesn't
exist.  The partition created by an old mkfs may not have unused region,
but in that case, the secondary super block will not be added.

This doesn't make more redundant copies of the super block; it is a future
work.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:20 -07:00
Ryusuke Konishi cece552074 nilfs2: simplify handling of active state of segments
will reduce some lines of segment constructor.  Previously, the state was
complexly controlled through a list of segments in order to keep
consistency in meta data of usage state of segments.  Instead, this
presents ``calculated'' active flags to userland cleaner program and stop
maintaining its real flag on disk.

Only by this fake flag, the cleaner cannot exactly know if each segment is
reclaimable or not.  However, the recent extension of nilfs_sustat ioctl
struct (nilfs2-extend-nilfs_sustat-ioctl-struct.patch) can prevent the
cleaner from reclaiming in-use segment wrongly.

So, now I can apply this for simplification.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:20 -07:00
Ryusuke Konishi c96fa464a5 nilfs2: mark minor flag for checkpoint created by internal operation
Nilfs creates checkpoints even for garbage collection or metadata updates
such as checkpoint mode change.  So, user often sees checkpoints created
only by such internal operations.

This is inconvenient in some situations.  For example, application that
monitors checkpoints and changes them to snapshots, will fall into an
infinite loop because it cannot distinguish internally created
checkpoints.

This patch solves this sort of problem by adding a flag to checkpoint for
identification.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:19 -07:00
Ryusuke Konishi 458c5b0822 nilfs2: clean up sketch file
The sketch file is a file to mark checkpoints with user data.  It was
experimentally introduced in the original implementation, and now
obsolete.  The file was handled differently with regular files; the file
size got truncated when a checkpoint was created.

This stops the special treatment and will treat it as a regular file.
Most users are not affected because mkfs.nilfs2 no longer makes this file.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:19 -07:00
Ryusuke Konishi 1f5abe7e7d nilfs2: replace BUG_ON and BUG calls triggerable from ioctl
Pekka Enberg advised me:
> It would be nice if BUG(), BUG_ON(), and panic() calls would be
> converted to proper error handling using WARN_ON() calls. The BUG()
> call in nilfs_cpfile_delete_checkpoints(), for example, looks to be
> triggerable from user-space via the ioctl() system call.

This will follow the comment and keep them to a minimum.

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:19 -07:00
Ryusuke Konishi 2c2e52fc4f nilfs2: extend nilfs_sustat ioctl struct
This adds a new argument to the nilfs_sustat structure.

The extended field allows to delete volatile active state of segments,
which was needed to protect freshly-created segments from garbage
collection but has confused code dealing with segments.  This
extension alleviates the mess and gives room for further
simplifications.

The volatile active flag is not persistent, so it's eliminable on this
occasion without affecting compatibility other than the ioctl change.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:19 -07:00
Ryusuke Konishi 1088dcf4c3 nilfs2: remove timedwait ioctl command
This removes NILFS_IOCTL_TIMEDWAIT command from ioctl interface along
with the related flags and wait queue.

The command is terrible because it just sleeps in the ioctl.  I prefer
to avoid this by devising means of event polling in userland program.
By reconsidering the userland GC daemon, I found this is possible
without changing behaviour of the daemon and sacrificing efficiency.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:18 -07:00
Ryusuke Konishi 47420c7998 nilfs2: avoid double error caused by nilfs_transaction_end
Pekka Enberg pointed out that double error handlings found after
nilfs_transaction_end() can be avoided by separating abort operation:

 OK, I don't understand this. The only way nilfs_transaction_end() can
 fail is if we have NILFS_TI_SYNC set and we fail to construct the
 segment. But why do we want to construct a segment if we don't commit?

 I guess what I'm asking is why don't we have a separate
 nilfs_transaction_abort() function that can't fail for the erroneous
 case to avoid this double error value tracking thing?

This does the separation and renames nilfs_transaction_end() to
nilfs_transaction_commit() for clarification.

Since, some calls of these functions were used just for exclusion control
against the segment constructor, they are replaced with semaphore
operations.

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:17 -07:00
Ryusuke Konishi f30bf3e40f nilfs2: fix missed-sync issue for do_sync_mapping_range()
Chris Mason pointed out that there is a missed sync issue in
nilfs_writepages():

On Wed, 17 Dec 2008 21:52:55 -0500, Chris Mason wrote:
> It looks like nilfs_writepage ignores WB_SYNC_NONE, which is used by
> do_sync_mapping_range().

where WB_SYNC_NONE in do_sync_mapping_range() was replaced with
WB_SYNC_ALL by Nick's patch (commit:
ee53a891f4).

This fixes the problem by letting nilfs_writepages() write out the log of
file data within the range if sync_mode is WB_SYNC_ALL.

This involves removal of nilfs_file_aio_write() which was previously
needed to ensure O_SYNC sync writes.

Cc: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:15 -07:00
Ryusuke Konishi 9ff05123e3 nilfs2: segment constructor
This adds the segment constructor (also called log writer).

The segment constructor collects dirty buffers for every dirty inode,
makes summaries of the buffers, assigns disk block addresses to the
buffers, and then submits BIOs for the buffers.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:15 -07:00