This UBIFS feature has never worked properly, and it was a mistake
to add it because we simply have no use-cases. So, lets still accept
the fast_unmount mount option, but ignore it. This does not change
much, because UBIFS commit in sync_fs anyway, and sync_fs is called
while unmounting.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

When mounting/re-mounting, UBIFS returns EINVAL even if the ENOSPC
or EROFS codes are are much better, just because we have not found
references to ENOSPC/EROFS in mount (2) man pages. This patch
changes this behaviour and makes UBIFS return real error code,
because:

1. It is just less confusing and more logical
2. mount is not described in SuSv3, so it seems to be not really
   well-standartized
3. we do not cover all cases, and any random undocumented in man
   pages error code may be returned anyway
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

- preserve the idx_gc list - it will be needed in the same
state, should UBIFS be remounted rw again
- prevent remounting ro if we have switched to read only
mode (due to a fatal error)
Signed-off-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

All writes go through wbufs so they must be sync'd
after syncing inodes and pages.
Signed-off-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

I introduce wrong assertions in one of the previous commits, this
patch fixes them.

Also, initialize debugfs after the debugging check. This is a little
nicer because we want the FS data to be accessible to external users
after everything has been initialized.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

When mounting read-only the orphan area head is
not initialized.  It must be initialized when
remounting read/write, but it was not.  This patch
fixes that.

[Artem: sorry, added comment tweaking noise]
Signed-off-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

When we mount UBIFS, GC LEB may contain out-of-date information,
and UBIFS should update lprops and set free space for thei LEB.
Currently UBIFS does this only if mounted R/W. But for R/O mount
we have to do the same, because otherwise we will have incorrect
FS free space reported to user-space.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

We observe space corrupted accounting when re-mounting. So add some
debbugging checks to catch problems like this.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

When freeing the c->idx_lebs list, we have to release the LEBs as well,
because we might be called from mount to read-only mode code. Otherwise
the LEBs stay taken forever, which may cause problems when we re-mount
back ro RW mode.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Just add more commentaries. Also some commentary fixes for
lprops flags.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Mark super, file, and inode operation structcutes with 'const'.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

VFS calls '->sync_fs()' twice - first time with @wait = 0, second
time with @wait = 1. As a result, we may commit and synchronize
write-buffers twice. Avoid doing this by returning immediatelly if
@wait = 0.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

WB_SYNC_HOLD is going to be zapped so we should not use it. Use
%WB_SYNC_NONE instead. Here is what akpm said:

"I think I'll just switch that to WB_SYNC_NONE.  The `wait==0' mode is
just an advisory thing to help the fs shove lots of data into the
queues.  If some gets missed then it'll be picked up on the second
->sync_fs call, with wait==1."

Thanks to Randy Dunlap for catching this.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Print node sizes and maximum node sizes.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

It is fine if there is not free space - we should still allow mounting
this FS. This patch relaxes the free space requirements and adds info
dumps.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBIFS commits on unmount to make the next mount faster. Currently,
it commits only if there is more than LEB size bytes in the
journal. This is not very good, because journal size may be
large (512KiB). And there may be few deletions in the journal
which do not take much journal space, but which do introduce
a lot of TNC changes and make mount slow.

Thus, jurt remove this condition and always commit.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBI now has (fake for now, though) synchronization call - use
it.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Always run commit in sync_fs, because even if the journal seems
to be almost empty, there may be a deletion which removes a large
file, which affects the index greatly. And because we want
better free space predictions after 'sync_fs()', we have to
commit.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Argh. The ->sync_fs call is called _before_ all inodes are flushed.
This means we first sync write buffers and commit, then all
inodes are synced, and we end up with unflushed write buffers!

Fix this by forcing synching all indoes from 'ubifs_sync_fs()'.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

The c->min_idx_lebs constant depends on c->old_idx_sz, which
is read from the master node. This means that we have to
initialize c->min_idx_lebs only after we have read the master
node.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Instead of using do_div(), use better primitives from
linux/math64.h.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Take into account that 2 eraseblocks are never available because
they are reserved for the index. This gives more realistic count
of FS blocks.

To avoid future confusions like this, introduce a constant.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

We need to have a possibility to see various UBIFS variables
and ask UBIFS to dump various information. Debugfs is what
we need.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Introduce a new data structure which contains all debugging
stuff inside. This is cleaner than having debugging stuff
directly in 'c'.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

It is very handy to be able to change default UBIFS compressor
via mount options. Introduce -o compr=<name> mount option support.
Currently only "none", "lzo" and "zlib" compressors are supported.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Save a 4 bytes of RAM per 'struct inode' by stroring inode
compression type in bit-filed, instead of using 'int'.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

To avoid memory allocation failure during bulk-read, pre-allocate
a bulk-read buffer, so that if there is only one bulk-reader at
a time, it would just use the pre-allocated buffer and would not
do any memory allocation. However, if there are more than 1 bulk-
reader, then only one reader would use the pre-allocated buffer,
while the other reader would allocate the buffer for itself.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Bulk-read allocates 128KiB or more using kmalloc. The allocation
starts failing often when the memory gets fragmented. UBIFS still
works fine in this case, because it falls-back to standard
(non-optimized) read method, though. This patch teaches bulk-read
to allocate exactly the amount of memory it needs, instead of
allocating 128KiB every time.

This patch is also a preparation to the further fix where we'll
have a pre-allocated bulk-read buffer as well. For example, now
the @bu object is prepared in 'ubifs_bulk_read()', so we could
path either pre-allocated or allocated information to
'ubifs_do_bulk_read()' later. Or teaching 'ubifs_do_bulk_read()'
not to allocate 'bu->buf' if it is already there.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Bulk-read allocates a lot of memory with 'kmalloc()', and when it
is/gets fragmented 'kmalloc()' fails with a scarry warning. But
because bulk-read is just an optimization, UBIFS keeps working fine.
Supress the warning by passing __GFP_NOWARN option to 'kmalloc()'.

This patch also introduces a macro for the magic 128KiB constant.
This is just neater.

Note, this is not really fixes the problem we had, but just hides
the warnings. The further patches fix the problem.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

It is better to print "Reserved for root" than
"Reserved pool size", because it is more obvious for users
what this means.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

This is a much better version of a previous patch to make the parser
tables constant. Rather than changing the typedef, we put the "const" in
all the various places where its required, allowing the __initconst
exception for nfsroot which was the cause of the previous trouble.

This was posted for review some time ago and I believe its been in -mm
since then.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Alexander Viro <aviro@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

sync_fs can be called even if the file system is mounted
read-only.  Ensure the commit is not run in that case.
Reported-by: NZoltan Sogor <weth@inf.u-szeged.hu>
Signed-off-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>

Commit the journal when the FS is sync'ed. This will make
statfs provide better free space report. And we anyway
advice our users to sync the FS if they want better statfs
report.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBIFS read performance can be improved by skipping the CRC
check when data nodes are read.  This option can be used if
the underlying media is considered to be highly reliable.
Note that CRCs are always checked for metadata.

Read speed on Arm platform with OneNAND goes from 19 MiB/s
to 27 MiB/s with data CRC checking disabled.
Signed-off-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>

Some flash media are capable of reading sequentially at faster rates.
UBIFS bulk-read facility is designed to take advantage of that, by
reading in one go consecutive data nodes that are also located
consecutively in the same LEB.

Read speed on Arm platform with OneNAND goes from 17 MiB/s to
19 MiB/s.
Signed-off-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>

In case of error, the function kthread_create returns an ERR pointer,
but never returns a NULL pointer. So a NULL test that comes before an
IS_ERR test should be deleted.

The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@match_bad_null_test@
expression x, E;
statement S1,S2;
@@
x = kthread_create(...)
... when != x = E
* if (x == NULL)
S1 else S2
// </smpl>
Signed-off-by: NJulien Brunel <brunel@diku.dk>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

This commit adds a reserved pool size print and tweaks the
prints to make them look nicer.

It also fixes and cleans-up some comments.

Additionally, it deletes some blank lines to make the code look
a little nicer.

In other words, nothing essential.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

If the ubifs partition is mounted RO and then remounted RW we end
up with no thread name in ubifs_remount_rw() and the thread appears
nameless.
Signed-off-by: NSebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

David Woodhouse suggested to be consistent with other FSes
and xor the beginning and the end of the UUID.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>