Snapshots and regular ro/rw mounts are essentially-different within
the meaning whether the checkpoint is static or not and is marked with
a snapshot flag or not.

The current implemenation, however, allows to remount a snapshot to a
regular rw-mount if the checkpoint number equals the latest one.

This transition is actually impossible since changing a checkpoint to
a snapshot makes another checkpoint, thus the condition is never
satisfied.

This fixes the weird state of affairs, and specifically separates
snapshots and regular rw/ro-mounts.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

deactivate_super was replaced with deactivate_locked_super, but the
comment of nilfs_get_sb remain unchanged.  This renews the comment.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

MS_VERBOSE is deprecated.  This replaces it with MS_SILENT in
reference to get_sb_bdev function.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

An fmode_t argument is passed to kill_block_super() through s_mode
member of the super_block structure.  This is used to release the
block device with the same mode, however, nilfs does not set s_mode
anywhere.

This modifies nilfs_get_sb function to properly initialize the s_mode
member.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

The second argument of open_bdev_exclusive/close_bdev_exclusive takes
fmode_t flags instead of mount flags.  This fixes the misuse.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This adds missing endian conversions in comparision of the magic
number of super blocks.  It was coincidence that prior versions didn't
incur problems; the upper byte of the magic number happened to be
equal to the lower byte.  But, semantically it's wrong to depend on
this.

This won't change anything else nor suffer any compatibility issues.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Printing a message after loading a file system is a practice. Add this to
provide a better user-friendly experience.
Signed-off-by: NLi Hong <lihong.hi@gmail.com>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

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: NLi Hong <lihong.hi@gmail.com>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Like ext3, nilfs has 'errors' mount option to allow specifying desired
behavior on severe errors.

Currently, the default action is 'errors=continue' and has potential
to advance filesystem corruption for severe errors.

This will change the action to 'errors=remount-ro' to avoid the issue.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

As of 32a88aa1, __sync_filesystem() will return 0 if s_bdi is not set.
And nilfs does not set s_bdi anywhere.  I noticed this problem by the
warning introduced by the recent commit 5129a469 ("Catch filesystem
lacking s_bdi").

 WARNING: at fs/super.c:959 vfs_kern_mount+0xc5/0x14e()
 Hardware name: PowerEdge 2850
 Modules linked in: nilfs2 loop tpm_tis tpm tpm_bios video shpchp pci_hotplug output dcdbas
 Pid: 3773, comm: mount.nilfs2 Not tainted 2.6.34-rc6-debug #38
 Call Trace:
  [<c1028422>] warn_slowpath_common+0x60/0x90
  [<c102845f>] warn_slowpath_null+0xd/0x10
  [<c1095936>] vfs_kern_mount+0xc5/0x14e
  [<c1095a03>] do_kern_mount+0x32/0xbd
  [<c10a811e>] do_mount+0x671/0x6d0
  [<c1073794>] ? __get_free_pages+0x1f/0x21
  [<c10a684f>] ? copy_mount_options+0x2b/0xe2
  [<c107b634>] ? strndup_user+0x48/0x67
  [<c10a81de>] sys_mount+0x61/0x8f
  [<c100280c>] sysenter_do_call+0x12/0x32

This ensures to set s_bdi for nilfs and fixes the sync silent failure.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Acked-by: NJens Axboe <jens.axboe@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This kills the following checkpatch warnings:

 WARNING: unnecessary whitespace before a quoted newline
 #869: FILE: super.c:869:
 +     	           "remount to a different snapshot. \n",

 WARNING: unnecessary whitespace before a quoted newline
 #389: FILE: the_nilfs.c:389:
 +     	    printk(KERN_ERR "NILFS: too short segment. \n");
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This fixes various typos I found in comments of nilfs2.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

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: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Jiro SEKIBA <jir@unicus.jp>

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: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.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: NJiro SEKIBA <jir@unicus.jp>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This adds "norecovery" mount option which disables temporal write
access to read-only mounts or snapshots during mount/recovery.
Without this option, write access will be even performed for those
types of mounts; the temporal write access is needed to mount root
file system read-only after an unclean shutdown.

This option will be helpful when user wants to prevent any write
access to the device.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Eric Sandeen <sandeen@redhat.com>

Although mount recovery of nilfs is integrated in load_nilfs()
procedure, the completion of recovery was isolated from the procedure
and performed at the end of the fill_super routine.

This was somewhat confusing since the recovery is needed for the nilfs
object, not for a super block instance.

To resolve the inconsistency, this will integrate the recovery
completion into load_nilfs().
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This will hide a function call of nilfs_mdt_clear() in
nilfs_mdt_destroy().

This ensures nilfs_mdt_destroy() to do cleanup jobs included in
nilfs_mdt_clear().
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This will displace nilfs_mdt_new() constructor with individual
metadata file constructors like nilfs_dat_new(), new_sufile_new(),
nilfs_cpfile_new(), and nilfs_ifile_new().

This makes it possible for each metadata file to have own
intialization code.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This adds an optional "object size" argument to nilfs_mdt_new_common()
function; the argument specifies the size of private object attached
to a newly allocated metadata file inode.

This will afford space to keep local variables for meta data files.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

match_bool function is not used anymore.
Signed-off-by: NJiro SEKIBA <jir@unicus.jp>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Since most of fs using nofoobar style option,
modified barrier=off option as nobarrier.
Signed-off-by: NJiro SEKIBA <jir@unicus.jp>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This gets rid of NILFS_CPFILE_GFP, NILFS_SUFILE_GFP, NILFS_DAT_GFP,
and NILFS_IFILE_GFP.  All of these constants refer to NILFS_MDT_GFP,
and can be removed.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: Add more safeguard routines and protections in mount process,
which also makes nilfs2 report consistency error messages when
checkpoint number is invalid.
Signed-off-by: NZhu Yanhai <zhu.yanhai@gmail.com>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: In procedure 'nilfs_get_sb()', when a nilfs filesysttem is
mounted for the first time, local variable 'nilfs->ns_last_cno' is
used before loading the latest checkpoint number from disk (in
'nilfs_fill_super'). 'nilfs->ns_last_cno' is assigned to 'sd.cno', but
'sd.cno' has never been used in the procedure.
Signed-off-by: NZhang Qiang <zhangqiang.buaa@gmail.com>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

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: NJiro SEKIBA <jir@unicus.jp>
Signed-off-by: NRyusuke 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: NJiro SEKIBA <jir@unicus.jp>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This fixes disorder of nilfs_write_super in nilfs_sync_fs.  Commiting
super block must be the end of the function so that every changes are
reflected.

->sync_fs() is not called frequently so this makes nilfs_sync_fs call
nilfs_commit_super instead of nilfs_write_super.
Signed-off-by: NJiro SEKIBA <jir@unicus.jp>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This removes redundant super block commit.

nilfs_write_super will call nilfs_commit_super to store super block
into block device.  However, nilfs_put_super will call
nilfs_commit_super right after calling nilfs_write_super.  So calling
nilfs_write_super in nilfs_put_super would be redundant.
Signed-off-by: NJiro SEKIBA <jir@unicus.jp>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This is a patch to display mount options in procfs.
Mount options will show up in the /proc/mounts as other fs does.

...
/dev/sda6 /mnt nilfs2 ro,relatime,barrier=off,cp=3,order=strict 0 0
...
Signed-off-by: NJiro SEKIBA <jir@unicus.jp>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

'ns_cno' of structure 'the_nilfs' must be protected from segment
writer, in other words, the caller of nilfs_get_checkpoint should hold
read lock for nilfs->ns_segctor_sem.  This patch adds the lock/unlock
operations in nilfs_attach_checkpoint() when calling
nilfs_cpfile_get_checkpoint().
Signed-off-by: NZhang Qiang <zhangqiang.buaa@gmail.com>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Actually, get rid of private analog, since nothing in there is
using ACLs at all so far.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NAl 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: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: NAl 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: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAl 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: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAl 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: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>