An fs-thaw ioctl causes deadlock with a chcp or mkcp -s command:
chcp D ffff88013870f3d0 0 1325 1324 0x00000004
...
Call Trace:
nilfs_transaction_begin+0x11c/0x1a0 [nilfs2]
wake_up_bit+0x20/0x20
copy_from_user+0x18/0x30 [nilfs2]
nilfs_ioctl_change_cpmode+0x7d/0xcf [nilfs2]
nilfs_ioctl+0x252/0x61a [nilfs2]
do_page_fault+0x311/0x34c
get_unmapped_area+0x132/0x14e
do_vfs_ioctl+0x44b/0x490
__set_task_blocked+0x5a/0x61
vm_mmap_pgoff+0x76/0x87
__set_current_blocked+0x30/0x4a
sys_ioctl+0x4b/0x6f
system_call_fastpath+0x16/0x1b
thaw D ffff88013870d890 0 1352 1351 0x00000004
...
Call Trace:
rwsem_down_failed_common+0xdb/0x10f
call_rwsem_down_write_failed+0x13/0x20
down_write+0x25/0x27
thaw_super+0x13/0x9e
do_vfs_ioctl+0x1f5/0x490
vm_mmap_pgoff+0x76/0x87
sys_ioctl+0x4b/0x6f
filp_close+0x64/0x6c
system_call_fastpath+0x16/0x1b
where the thaw ioctl deadlocked at thaw_super() when called while chcp was
waiting at nilfs_transaction_begin() called from
nilfs_ioctl_change_cpmode(). This deadlock is 100% reproducible.
This is because nilfs_ioctl_change_cpmode() first locks sb->s_umount in
read mode and then waits for unfreezing in nilfs_transaction_begin(),
whereas thaw_super() locks sb->s_umount in write mode. The locking of
sb->s_umount here was intended to make snapshot mounts and the downgrade
of snapshots to checkpoints exclusive.
This fixes the deadlock issue by replacing the sb->s_umount usage in
nilfs_ioctl_change_cpmode() with a dedicated mutex which protects snapshot
mounts.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Tested-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This directly uses sb->s_fs_info to keep a nilfs filesystem object and
fully removes the intermediate nilfs_sb_info structure. With this
change, the hierarchy of on-memory structures of nilfs will be
simplified as follows:
Before:
super_block
-> nilfs_sb_info
-> the_nilfs
-> cptree --+-> nilfs_root (current file system)
+-> nilfs_root (snapshot A)
+-> nilfs_root (snapshot B)
:
-> nilfs_sc_info (log writer structure)
After:
super_block
-> the_nilfs
-> cptree --+-> nilfs_root (current file system)
+-> nilfs_root (snapshot A)
+-> nilfs_root (snapshot B)
:
-> nilfs_sc_info (log writer structure)
The reason why we didn't design so from the beginning is because the
initial shape also differed from the above. The early hierachy was
composed of "per-mount-point" super_block -> nilfs_sb_info pairs and a
shared nilfs object. On the kernel 2.6.37, it was changed to the
current shape in order to unify super block instances into one per
device, and this cleanup became applicable as the result.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Log writer is held by the nilfs_sb_info structure. This moves it into
nilfs object and replaces all uses of NILFS_SC() accessor.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Moves s_next_generation counter and a spinlock protecting it to nilfs
object from nilfs_sb_info structure.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Moves s_inode_lock spinlock and s_dirty_files list to nilfs object
from nilfs_sb_info structure.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This moves four parameter variables on nilfs_sb_info s_resuid,
s_resgid, s_interval and s_watermark to the nilfs object.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Nilfs now can use sb->s_bdi to get backing_dev_info, so we use it
instead of ns_bdi on the nilfs object and remove ns_bdi.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Nilfs object holds a back pointer to a writable super block instance
in nilfs->ns_writer, and this became eliminable since sb is now made
per device and all inodes have a valid pointer to it.
This deletes the ns_writer pointer and a reader/writer semaphore
protecting it.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
After applied the patch that unified sb instances, root dentry of
snapshots can be left in dcache even after their trees are unmounted.
The orphan root dentry/inode keeps a root object, and this causes
false positive of nilfs_checkpoint_is_mounted function.
This resolves the issue by having nilfs_checkpoint_is_mounted test
whether the root dentry is busy or not.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This applies prepared rollback function and redirect function of
metadata file to DAT file, and eliminates GCDAT inode.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This stops pre-allocating nilfs object in nilfs_get_sb routine, and
stops managing its life cycle by reference counting.
nilfs_find_or_create_nilfs() function, nilfs->ns_mount_mutex,
nilfs_objects list, and the reference counter will be removed through
the simplification.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This stops allocating multiple super block instances for a device.
All snapshots and a current mode mount (i.e. latest tree) will be
controlled with nilfs_root objects that are kept within an sb
instance.
nilfs_get_sb() is rewritten so that it always has a root object for
the latest tree and snapshots make additional root objects.
The root dentry of the latest tree is binded to sb->s_root even if it
isn't attached on a directory. Root dentries of snapshots or the
latest tree are binded to mnt->mnt_root on which they are mounted.
With this patch, nilfs_find_sbinfo() function, nilfs->ns_supers list,
and nilfs->ns_current back pointer, are deleted. In addition,
init_nilfs() and load_nilfs() are simplified since they will be called
once for a device, not repeatedly called for mount points.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
To hold multiple versions of a filesystem in one sb instance, a new
on-memory structure is necessary to handle one or more checkpoints.
This adds a red-black tree of checkpoints to nilfs object, and adds
lookup and create functions for them.
Each checkpoint is represented by "nilfs_root" structure, and this
structure has rb_node to configure the rb-tree.
The nilfs_root object is identified with a checkpoint number. For
each snapshot, a nilfs_root object is allocated and the checkpoint
number of snapshot is assigned to it. For a regular mount
(i.e. current mode mount), NILFS_CPTREE_CURRENT_CNO constant is
assigned to the corresponding nilfs_root object.
Each nilfs_root object has an ifile inode and some counters. These
items will displace those of nilfs_sb_info structure in successive
patches.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This uses inode hash function that vfs provides instead of the own
hash table for caching gc inodes. This finally removes the own inode
hash from nilfs.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
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>
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>
This stores blocksize in nilfs objects for the successive refactoring
of recovery logic.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
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>
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>
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>
This adds a helper function, nilfs_valid_fs() which returns if nilfs
is in a valid state or not.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This is a re-revised patch to shorten freeze period.
This version include a fix of the bug Konishi-san mentioned last time.
When GC is runnning, GC moves live block to difference segments.
Copying live blocks into memory is done in a transaction,
however it is not necessarily to be in the transaction.
This patch will get the nilfs_ioctl_move_blocks() out from
transaction lock and put it before the transaction.
I ran sysbench fileio test against nilfs partition.
I copied some DVD/CD images and created snapshot to create live blocks
before starting the benchmark.
Followings are summary of rc8 and rc8 w/ the patch of per-request
statistics, which is min/max and avg. I ran each test three times and
bellow is average of those numers.
According to this benchmark result, average time is slightly degrated.
However, worstcase (max) result is significantly improved.
This can address a few seconds write freeze.
- random write per-request performance of rc8
min 0.843ms
max 680.406ms
avg 3.050ms
- random write per-request performance of rc8 w/ this patch
min 0.843ms -> 100.00%
max 380.490ms -> 55.90%
avg 3.233ms -> 106.00%
- sequential write per-request performance of rc8
min 0.736ms
max 774.343ms
avg 2.883ms
- sequential write per-request performance of rc8 w/ this patch
min 0.720ms -> 97.80%
max 644.280ms-> 83.20%
avg 3.130ms -> 108.50%
-----8<-----8<-----nilfs_cleanerd.conf-----8<-----8<-----
protection_period 150
selection_policy timestamp # timestamp in ascend order
nsegments_per_clean 2
cleaning_interval 2
retry_interval 60
use_mmap
log_priority info
-----8<-----8<-----nilfs_cleanerd.conf-----8<-----8<-----
Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Separate conditions that check if syncing super block and alternative
super block are required as inline functions to reuse the conditions.
Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
will get rid of nilfs_get_writer() and nilfs_put_writer() pair used to
retain a writable FS-instance for a period.
The pair functions were making up some kind of recursive lock with a
mutex, but they became overkill since the commit
201913ed74. Furthermore, they caused
the following lockdep warning because the mutex can be released by a
task which didn't lock it:
=====================================
[ BUG: bad unlock balance detected! ]
-------------------------------------
kswapd0/422 is trying to release lock (&nilfs->ns_writer_mutex) at:
[<c1359ff5>] mutex_unlock+0x8/0xa
but there are no more locks to release!
other info that might help us debug this:
no locks held by kswapd0/422.
stack backtrace:
Pid: 422, comm: kswapd0 Not tainted 2.6.31-rc4-nilfs #51
Call Trace:
[<c1358f97>] ? printk+0xf/0x18
[<c104fea7>] print_unlock_inbalance_bug+0xcc/0xd7
[<c11578de>] ? prop_put_global+0x3/0x35
[<c1050195>] lock_release+0xed/0x1dc
[<c1359ff5>] ? mutex_unlock+0x8/0xa
[<c1359f83>] __mutex_unlock_slowpath+0xaf/0x119
[<c1359ff5>] mutex_unlock+0x8/0xa
[<d1284add>] nilfs_mdt_write_page+0xd8/0xe1 [nilfs2]
[<c1092653>] shrink_page_list+0x379/0x68d
[<c109171b>] ? isolate_pages_global+0xb4/0x18c
[<c1092bd2>] shrink_list+0x26b/0x54b
[<c10930be>] shrink_zone+0x20c/0x2a2
[<c10936b7>] kswapd+0x407/0x591
[<c1091667>] ? isolate_pages_global+0x0/0x18c
[<c1040603>] ? autoremove_wake_function+0x0/0x33
[<c10932b0>] ? kswapd+0x0/0x591
[<c104033b>] kthread+0x69/0x6e
[<c10402d2>] ? kthread+0x0/0x6e
[<c1003e33>] kernel_thread_helper+0x7/0x1a
This patch uses a reader/writer semaphore instead of the own lock and
kills this warning.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
will fix kernel oopses like the following:
# mount -t nilfs2 -r -o cp=20 /dev/sdb1 /test1
# mount -t nilfs2 -r -o cp=20 /dev/sdb1 /test2
# umount /test1
# umount /test2
BUG: sleeping function called from invalid context at arch/x86/mm/fault.c:1069
in_atomic(): 0, irqs_disabled(): 1, pid: 3886, name: umount.nilfs2
1 lock held by umount.nilfs2/3886:
#0: (&type->s_umount_key#31){+.+...}, at: [<c10b398a>] deactivate_super+0x52/0x6c
irq event stamp: 1219
hardirqs last enabled at (1219): [<c135c774>] __mutex_unlock_slowpath+0xf8/0x119
hardirqs last disabled at (1218): [<c135c6d5>] __mutex_unlock_slowpath+0x59/0x119
softirqs last enabled at (1214): [<c1033316>] __do_softirq+0x1a5/0x1ad
softirqs last disabled at (1205): [<c1033354>] do_softirq+0x36/0x5a
Pid: 3886, comm: umount.nilfs2 Not tainted 2.6.31-rc6 #55
Call Trace:
[<c1023549>] __might_sleep+0x107/0x10e
[<c13603c0>] do_page_fault+0x246/0x397
[<c136017a>] ? do_page_fault+0x0/0x397
[<c135e753>] error_code+0x6b/0x70
[<c136017a>] ? do_page_fault+0x0/0x397
[<c104f805>] ? __lock_acquire+0x91/0x12fd
[<c1050a62>] ? __lock_acquire+0x12ee/0x12fd
[<c1050a62>] ? __lock_acquire+0x12ee/0x12fd
[<c1050b2b>] lock_acquire+0xba/0xdd
[<d0d17d3f>] ? nilfs_detach_segment_constructor+0x2f/0x2fa [nilfs2]
[<c135d4fe>] down_write+0x2a/0x46
[<d0d17d3f>] ? nilfs_detach_segment_constructor+0x2f/0x2fa [nilfs2]
[<d0d17d3f>] nilfs_detach_segment_constructor+0x2f/0x2fa [nilfs2]
[<c104ea2c>] ? mark_held_locks+0x43/0x5b
[<c104ecb1>] ? trace_hardirqs_on_caller+0x10b/0x133
[<c104ece4>] ? trace_hardirqs_on+0xb/0xd
[<d0d09ac1>] nilfs_put_super+0x2f/0xca [nilfs2]
[<c10b3352>] generic_shutdown_super+0x49/0xb8
[<c10b33de>] kill_block_super+0x1d/0x31
[<c10e6599>] ? vfs_quota_off+0x0/0x12
[<c10b398f>] deactivate_super+0x57/0x6c
[<c10c4bc3>] mntput_no_expire+0x8c/0xb4
[<c10c5094>] sys_umount+0x27f/0x2a4
[<c10c50c6>] sys_oldumount+0xd/0xf
[<c10031a4>] sysenter_do_call+0x12/0x38
...
This turns out to be a bug brought by an -rc1 patch ("nilfs2: simplify
remaining sget() use").
In the patch, a new "put resource" function, nilfs_put_sbinfo()
was introduced to delay freeing nilfs_sb_info struct.
But the nilfs_put_sbinfo() mistakenly used atomic_dec_and_test()
function to check the reference count, and it caused the nilfs_sb_info
was freed when user mounted a snapshot twice.
This bug also suggests there was unseen memory leak in usual mount
/umount operations for nilfs.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This will remove every bd_mount_sem use in nilfs.
The intended exclusion control was replaced by the previous patch
("nilfs2: correct exclusion control in nilfs_remount function") for
nilfs_remount(), and this patch will replace remains with a new mutex
that this inserts in nilfs object.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
nilfs_remount() changes mount state of a superblock instance. Even
though nilfs accesses other superblock instances during mount or
remount, the mount state was not properly protected in
nilfs_remount().
Moreover, nilfs_remount() has a lock order reversal problem;
nilfs_get_sb() holds:
1. bdev->bd_mount_sem
2. sb->s_umount (sget acquires)
and nilfs_remount() holds:
1. sb->s_umount (locked by the caller in vfs)
2. bdev->bd_mount_sem
To avoid these problems, this patch divides a semaphore protecting
super block instances from nilfs->ns_sem, and applies it to the mount
state protection in nilfs_remount().
With this change, bd_mount_sem use is removed from nilfs_remount() and
the lock order reversal will be resolved. And the new rw-semaphore,
nilfs->ns_super_sem will properly protect the mount state except the
modification from nilfs_error function.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This simplifies the test function passed on the remaining sget()
callsite in nilfs.
Instead of checking mount type (i.e. ro-mount/rw-mount/snapshot mount)
in the test function passed to sget(), this patch first looks up the
nilfs_sb_info struct which the given mount type matches, and then
acquires the super block instance holding the nilfs_sb_info.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This stops using sget() for checking if an r/w-mount or an r/o-mount
exists on the device. This elimination uses a back pointer to the
current mount added to nilfs object.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This will change the way to obtain nilfs object in nilfs_get_sb()
function.
Previously, a preliminary sget() call was performed, and the nilfs
object was acquired from a super block instance found by the sget()
call.
This patch, instead, instroduces a new dedicated function
find_or_create_nilfs(); as the name implies, the function finds an
existent nilfs object from a global list or creates a new one if no
object is found on the device.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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>
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>
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>
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>
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>
This adds the following common structures of the NILFS2 file system.
* nilfs_inode_info structure:
gives on-memory inode.
* nilfs_sb_info structure:
keeps per-mount state and a special inode for the ifile.
This structure is attached to the super_block structure.
* the_nilfs structure:
keeps shared state and locks among a read/write mount and snapshot
mounts. This keeps special inodes for the sufile, cpfile, dat, and
another dat inode used during GC (gcdat). This also has a hash table
of dummy inodes to cache disk blocks during GC (gcinodes).
* nilfs_transaction_info structure:
keeps per task state while nilfs is writing logs or doing indivisible
inode or namespace operations. This structure is used to identify
context during log making and store nest level of the lock which
ensures atomicity of file system operations.
Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
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>
