jffs2: Allow setting rp_size to zero during remounting

Set rp_size to zero will be ignore during remounting.

The method to identify whether we input a remounting option of
rp_size is to check if the rp_size input is zero. It can not work
well if we pass "rp_size=0".

This patch add a bool variable "set_rp_size" to fix this problem.

Reported-by: Jubin Zhong <zhongjubin@huawei.com>
Signed-off-by: lizhe <lizhe67@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

jffs2: Improve post-mount CRC scan efficiency

We need to finish doing the CRC checks before we can allow writes to
happen, and we currently process the inodes in order. This means a call
to jffs2_get_ino_cache() for each possible inode# up to c->highest_ino.

There may be a lot of lookups which fail, if the inode# space is used
sparsely. And the inode# space is *often* used sparsely, if a file
system contains a lot of stuff that was put there in the original
image, followed by lots of creation and deletion of new files.

Instead of processing them numerically with a lookup each time, just
walk the hash buckets instead.

[fix locking typo reported by Dan Carpenter]
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

[jffs2] kill wbuf_queued/wbuf_dwork_lock

schedule_delayed_work() happening when the work is already pending is
a cheap no-op. Don't bother with ->wbuf_queued logics - it's both
broken (cancelling ->wbuf_dwork leaves it set, as spotted by Jeff Harris)
and pointless. It's cheaper to let schedule_delayed_work() handle that
case.

Reported-by: Jeff Harris <jefftharris@gmail.com>
Tested-by: Jeff Harris <jefftharris@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

jffs2: get rid of jffs2_sync_super

Currently JFFS2 file-system maps the VFS "superblock" abstraction to the
write-buffer. Namely, it uses VFS services to synchronize the write-buffer
periodically.

The whole "superblock write-out" VFS infrastructure is served by the
'sync_supers()' kernel thread, which wakes up every 5 (by default) seconds and
writes out all dirty superblock using the '->write_super()' call-back. But the
problem with this thread is that it wastes power by waking up the system every
5 seconds no matter what. So we want to kill it completely and thus, we need to
make file-systems to stop using the '->write_super' VFS service, and then
remove it together with the kernel thread.

This patch switches the JFFS2 write-buffer management from
'->write_super()'/'->s_dirt' to a delayed work. Instead of setting the 's_dirt'
flag we just schedule a delayed work for synchronizing the write-buffer.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

jffs2: get rid of jffs2_sync_super

Currently JFFS2 file-system maps the VFS "superblock" abstraction to the
write-buffer. Namely, it uses VFS services to synchronize the write-buffer
periodically.

The whole "superblock write-out" VFS infrastructure is served by the
'sync_supers()' kernel thread, which wakes up every 5 (by default) seconds and
writes out all dirty superblock using the '->write_super()' call-back. But the
problem with this thread is that it wastes power by waking up the system every
5 seconds no matter what. So we want to kill it completely and thus, we need to
make file-systems to stop using the '->write_super' VFS service, and then
remove it together with the kernel thread.

This patch switches the JFFS2 write-buffer management from
'->write_super()'/'->s_dirt' to a delayed work. Instead of setting the 's_dirt'
flag we just schedule a delayed work for synchronizing the write-buffer.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

JFFS2: Add parameter to reserve disk space for root

Add a new rp_size= parameter which creates a "reserved pool" of disk
space which can only be used by root. Other users are not permitted
to write to disk when the available space is less than the pool size.

Based on original code by Artem Bityutskiy in
https://dev.laptop.org/ticket/5317

[dwmw2: use capable(CAP_SYS_RESOURCE) not uid/gid check, fix debug prints]
Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

jffs2: implement mount option parsing and compression overriding

Currently jffs2 has compile-time constants (and .config options)
controlling whether or not the various compression/decompression
drivers are built in and enabled. This is fine for embedded
systems, but it clashes with distribution kernels. Distro kernels
tend to turn on everything; this causes OpenFirmware to fall
over, as it understands ZLIB-compressed inodes. Booting a kernel
that has LZO compression enabled, writing to the boot partition,
and then rebooting causes OFW to fail to read the kernel from
the filesystem. This is because LZO compression has priority
when writing new data to jffs2, if LZO is enabled.

This patch adds mount option parsing, and a single supported
option ("compr=none"). This adds the flexibility of being
able to specify which compressor overrides on a per-superblock
basis. For now, we can simply disable compression;
additional flexibility coming soon.

v2: kill some printks, and implement show_options as suggested
by Artem Bityutskiy.

Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>

jffs2: typo in comment

It says FB instead of FS (file system).

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

jffs2: Dynamically choose inocache hash size

When JFFS2 is used for large volumes, the mount times are quite long.
Increasing the hash size provides a significant speed boost on the OLPC
XO-1 laptop.

Add logic that dynamically selects a hash size based on the size of
the medium. A 64mb medium will result in a hash size of 128, and a 512mb
medium will result in a hash size of 1024.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

jffs2: Update copyright notices

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2] Add erase_checking_list to hold blocks being marked.

Just to keep the debug code happy when it's adding all the blocks up.
Otherwise, they disappear for a while while the locks are dropped to
check them and write the cleanmarker.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2] semaphore->mutex conversion

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

Convert asm/semaphore.h users to linux/semaphore.h

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>

[JFFS2] Trigger garbage collection when very_dirty_list size becomes excessive

With huge amounts of free space, we weren't bothering to GC for while a
while, and pathological numbers of obsolete nodes were accumulating,
seriously affecting performance on NAND flash (OLPC trac #3978)

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2] Add support for write-buffer verification.

We've seen some evil corruption issues, where the corruption seems to be
introduced after the JFFS2 crc32 is calculated but before the NAND
controller calculates the ECC. So it's in RAM or in the PCI DMA
transfer; not on the flash. Attempt to catch it earlier by (optionally)
reading back from the flash immediately after writing it.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2] Tidy up licensing/copyright boilerplate.

In particular, remove the bit in the LICENCE file about contacting
Red Hat for alternative arrangements. Their errant IS department broke
that arrangement a long time ago -- the policy of collecting copyright
assignments from contributors came to an end when the plug was pulled on
the servers hosting the project, without notice or reason.

We do still dual-license it for use with eCos, with the GPL+exception
licence approved by the FSF as being GPL-compatible. It's just that nobody
has the right to license it differently.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2] Use MTD_OOB_AUTO to automatically place cleanmarker on NAND

Nowadays MTD supports an MTD_OOB_AUTO option which allows users
to access free bytes in NAND's OOB as a contiguous buffer, although
it may be highly discontinuous.

This patch teaches JFFS2 to use this nice feature instead of the
old MTD_OOB_PLACE option. This for example caused problems with
OneNAND. Now JFFS2 does not care how are the free bytes situated.

This may change position of the clean marker on some flashes,
but this is not a problem. JFFS2 will just re-erase the empty
eraseblocks and write the new (correct) clean marker.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2][XATTR] using 'delete marker' for xdatum/xref deletion

- When xdatum is removed, a new xdatum with 'delete marker' is
written. (version==0xffffffff means 'delete marker')
- When xref is removed, a new xref with 'delete marker' is written.
(odd-numbered xseqno means 'delete marker')

- delete_xattr_(datum/xref)_delay() are new deletion functions
are added. We can only use them if we can detect the target
obsolete xdatum/xref as a orphan or errir one.
(e.g when inode deletion, or detecting crc error)

[1/3] jffs2-xattr-v6-01-delete_marker.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[MTD] Rework the out of band handling completely

Hopefully the last iteration on this!

The handling of out of band data on NAND was accompanied by tons of fruitless
discussions and halfarsed patches to make it work for a particular
problem. Sufficiently annoyed by I all those "I know it better" mails and the
resonable amount of discarded "it solves my problem" patches, I finally decided
to go for the big rework. After removing the _ecc variants of mtd read/write
functions the solution to satisfy the various requirements was to refactor the
read/write _oob functions in mtd.

The major change is that read/write_oob now takes a pointer to an operation
descriptor structure "struct mtd_oob_ops".instead of having a function with at
least seven arguments.

read/write_oob which should probably renamed to a more descriptive name, can do
the following tasks:

- read/write out of band data
- read/write data content and out of band data
- read/write raw data content and out of band data (ecc disabled)

struct mtd_oob_ops has a mode field, which determines the oob handling mode.

Aside of the MTD_OOB_RAW mode, which is intended to be especially for
diagnostic purposes and some internal functions e.g. bad block table creation,
the other two modes are for mtd clients:

MTD_OOB_PLACE puts/gets the given oob data exactly to/from the place which is
described by the ooboffs and ooblen fields of the mtd_oob_ops strcuture. It's
up to the caller to make sure that the byte positions are not used by the ECC
placement algorithms.

MTD_OOB_AUTO puts/gets the given oob data automaticaly to/from the places in
the out of band area which are described by the oobfree tuples in the ecclayout
data structre which is associated to the devicee.

The decision whether data plus oob or oob only handling is done depends on the
setting of the datbuf member of the data structure. When datbuf == NULL then
the internal read/write_oob functions are selected, otherwise the read/write
data routines are invoked.

Tested on a few platforms with all variants. Please be aware of possible
regressions for your particular device / application scenario

Disclaimer: Any whining will be ignored from those who just contributed "hot
air blurb" and never sat down to tackle the underlying problem of the mess in
the NAND driver grown over time and the big chunk of work to fix up the
existing users. The problem was not the holiness of the existing MTD
interfaces. The problems was the lack of time to go for the big overhaul. It's
easy to add more mess to the existing one, but it takes alot of effort to go
for a real solution.

Improvements and bugfixes are welcome!

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

[MTD] NAND Replace oobinfo by ecclayout

The nand_oobinfo structure is not fitting the newer error correction
demands anymore. Replace it by struct nand_ecclayout and fixup the users
all over the place. Keep the nand_oobinfo based ioctl for user space
compability reasons.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

[JFFS2] Switch to using an array of jffs2_raw_node_refs instead of a list.

This allows us to drop another pointer from the struct jffs2_raw_node_ref,
shrinking it to 8 bytes on 32-bit machines (if the TEST_TOTLEN) paranoia
check is turned off, which will be committed soon).

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2] Reduce visibility of raw_node_ref to upper layers of JFFS2 code.

As the first step towards eliminating the ref->next_phys member and saving
memory by using an _array_ of struct jffs2_raw_node_ref per eraseblock,
stop the write functions from allocating their own refs; have them just
_reserve_ the appropriate number instead. Then jffs2_link_node_ref() can
just fill them in.

Use a linked list of pre-allocated refs in the superblock, for now. Once
we switch to an array, it'll just be a case of extending that array.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2][XATTR] Remove 'struct list_head ilist' from jffs2_inode_cache.

This patch can reduce 4-byte of memory usage per inode_cache.

[4/10] jffs2-xattr-v5.1-04-remove_ilist_from_ic.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>

[JFFS2][XATTR] XATTR support on JFFS2 (version. 5)

This attached patches provide xattr support including POSIX-ACL and
SELinux support on JFFS2 (version.5).

There are some significant differences from previous version posted
at last December.
The biggest change is addition of EBS(Erase Block Summary) support.
Currently, both kernel and usermode utility (sumtool) can recognize
xattr nodes which have JFFS2_NODETYPE_XATTR/_XREF nodetype.

In addition, some bugs are fixed.
- A potential race condition was fixed.
- Unexpected fail when updating a xattr by same name/value pair was fixed.
- A bug when removing xattr name/value pair was fixed.

The fundamental structures (such as using two new nodetypes and exclusion
mechanism by rwsem) are unchanged. But most of implementation were reviewed
and updated if necessary.
Espacially, we had to change several internal implementations related to
load_xattr_datum() to avoid a potential race condition.

[1/2] xattr_on_jffs2.kernel.version-5.patch
[2/2] xattr_on_jffs2.utils.version-5.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

Move jffs2_fs_i.h and jffs2_fs_sb.h from include/linux/ to fs/jffs2/

Signed-off-by: David Woodhouse <dwmw2@infradead.org>