The patch below updates the jbd stats patch to 2.6.20/jbd2.
The initial patch was posted by Alex Tomas in December 2005
(http://marc.info/?l=linux-ext4&m=113538565128617&w=2).
It provides statistics via procfs such as transaction lifetime and size.

Sometimes, investigating performance problems, i find useful to have
stats from jbd about transaction's lifetime, size, etc. here is a
patch for review and inclusion probably.

for example, stats after creation of 3M files in htree directory:

[root@bob ~]# cat /proc/fs/jbd/sda/history
R/C  tid   wait  run   lock  flush log   hndls  block inlog ctime write drop  close
R    261   8260  2720  0     0     750   9892   8170  8187
C    259                                                    750   0     4885  1
R    262   20    2200  10    0     770   9836   8170  8187
R    263   30    2200  10    0     3070  9812   8170  8187
R    264   0     5000  10    0     1340  0      0     0
C    261                                                    8240  3212  4957  0
R    265   8260  1470  0     0     4640  9854   8170  8187
R    266   0     5000  10    0     1460  0      0     0
C    262                                                    8210  2989  4868  0
R    267   8230  1490  10    0     4440  9875   8171  8188
R    268   0     5000  10    0     1260  0      0     0
C    263                                                    7710  2937  4908  0
R    269   7730  1470  10    0     3330  9841   8170  8187
R    270   0     5000  10    0     830   0      0     0
C    265                                                    8140  3234  4898  0
C    267                                                    720   0     4849  1
R    271   8630  2740  20    0     740   9819   8170  8187
C    269                                                    800   0     4214  1
R    272   40    2170  10    0     830   9716   8170  8187
R    273   40    2280  0     0     3530  9799   8170  8187
R    274   0     5000  10    0     990   0      0     0


where,

R     - line for transaction's life from T_RUNNING to T_FINISHED
C     - line for transaction's checkpointing
tid   - transaction's id
wait  - for how long we were waiting for new transaction to start
         (the longest period journal_start() took in this transaction)
run   - real transaction's lifetime (from T_RUNNING to T_LOCKED
lock  - how long we were waiting for all handles to close
         (time the transaction was in T_LOCKED)
flush - how long it took to flush all data (data=ordered)
log   - how long it took to write the transaction to the log
hndls - how many handles got to the transaction
block - how many blocks got to the transaction
inlog - how many blocks are written to the log (block + descriptors)
ctime - how long it took to checkpoint the transaction
write - how many blocks have been written during checkpointing
drop  - how many blocks have been dropped during checkpointing
close - how many running transactions have been closed to checkpoint this one

all times are in msec.


[root@bob ~]# cat /proc/fs/jbd/sda/info
280 transaction, each upto 8192 blocks
average:
  1633ms waiting for transaction
  3616ms running transaction
  5ms transaction was being locked
  1ms flushing data (in ordered mode)
  1799ms logging transaction
  11781 handles per transaction
  5629 blocks per transaction
  5641 logged blocks per transaction
Signed-off-by: Johann Lombardi <johann.lombardi@bull.net>
Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>

When we are overwriting a file and not actually allocating new file system
blocks we need to take only the read lock on i_data_sem.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

We are currently taking the truncate_mutex for every read. This would have
performance impact on large CPU configuration. Convert the lock to read write
semaphore and take read lock when we are trying to read the file.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

When doing a migrate from ext3 to ext4 inode we need to make sure the test
for inode type and walking inode data happens inside  lock. To make this
happen move truncate_mutex early before checking the i_flags.


This actually should enable us to remove the verify_chain().
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

The unused code found in ext3_find_entry() is also present (and still
unused) in the ext4_find_entry() code. This patch removes it.
Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

ext4_ext_get_blocks returns negative values on error. We should
check for  <= 0
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Before we start committing a transaction, we call
__journal_clean_checkpoint_list() to cleanup transaction's written-back
buffers.

If this call happens to remove all of them (and there were already some
buffers), __journal_remove_checkpoint() will decide to free the transaction
because it isn't (yet) a committing transaction and soon we fail some
assertion - the transaction really isn't ready to be freed :).

We change the check in __journal_remove_checkpoint() to free only a
transaction in T_FINISHED state.  The locking there is subtle though (as
everywhere in JBD ;().  We use j_list_lock to protect the check and a
subsequent call to __journal_drop_transaction() and do the same in the end
of journal_commit_transaction() which is the only place where a transaction
can get to T_FINISHED state.

Probably I'm too paranoid here and such locking is not really necessary -
checkpoint lists are processed only from log_do_checkpoint() where a
transaction must be already committed to be processed or from
__journal_clean_checkpoint_list() where kjournald itself calls it and thus
transaction cannot change state either.  Better be safe if something
changes in future...
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Chris Snook <csnook@redhat.com>
Cc: "Stephen C. Tweedie" <sct@redhat.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

When a new block bitmap is read from disk in read_block_bitmap()
there are a few bits that should ALWAYS be set.  In particular,
the blocks given corresponding to block bitmap, inode bitmap and inode tables.
Validate the block bitmap against these blocks.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Add buffer head related helper function bh_uptodate_or_lock and
bh_submit_read which can be used by file system
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

ext4 file system was by default ignoring errors and continuing. This
is not a good default as continuing on error could lead to file system
corruption. Change the default to mark the file system
readonly. Debian and ubuntu already does this as the default in their
fstab.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>

When mounting an ext4 filesystem with corrupted s_first_data_block, things
can go very wrong and oops.

Because blocks_count in ext4_fill_super is a u64, and we must use do_div,
the calculation of db_count is done differently than on ext4.  If
first_data_block is corrupted such that it is larger than ext4_blocks_count,
for example, then the intermediate blocks_count value may go negative,
but sign-extend to a very large value:

        blocks_count = (ext4_blocks_count(es) -
                        le32_to_cpu(es->s_first_data_block) +
                        EXT4_BLOCKS_PER_GROUP(sb) - 1);

This is then assigned to s_groups_count which is an unsigned long:

        sbi->s_groups_count = blocks_count;

This may result in a value of 0xFFFFFFFF which is then used to compute
db_count:

        db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
                   EXT4_DESC_PER_BLOCK(sb);

and in this case db_count will wind up as 0 because the addition overflows
32 bits.  This in turn causes the kmalloc for group_desc to be of 0 size:

        sbi->s_group_desc = kmalloc(db_count * sizeof (struct buffer_head *),
                                    GFP_KERNEL);

and eventually in ext4_check_descriptors, dereferencing
sbi->s_group_desc[desc_block] will result in a NULL pointer dereference.

The simplest test seems to be to sanity check s_first_data_block,
EXT4_BLOCKS_PER_GROUP, and ext4_blocks_count values to be sure
their combination won't result in a bad intermediate value for
blocks_count.  We could just check for db_count == 0, but
catching it at the root cause seems like it provides more info.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Mingming Cao <cmm@us.ibm.com>

Based on a report by Robert P. J. Day.
Signed-off-by: Adrian Bunk <bunk@kernel.org>

This fix some instances where we were continuing after calling
ext4_error. ext4_error call panic only if errors=panic mount option is
set. So we need to make sure we return correctly after ext4_error call

Reported by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

This patch extends bg_itable_unused of ext4 group descriptor
from 16bit into 32bit. In order to add bg_itable_unused_hi into
struct ext4_group_desc, some extra fields which are already introduced into
e2fsprogs are also added in for consistency.
Signed-off-by: Coly Li <coyli@suse.de>
Cc: Andreas Dilger <adilger@clusterfs.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>

The max file size for ext3 file system is now calculated
with hardcoded 4K block size. The patch fixes it to be
calculated with the right block size.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

The max file size for ext2 file system is now calculated
with hardcoded 4K block size. The patch fixes it to be
calculated with the right block size.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Calculate & store the max offset for bitmapped files, and
catch too-large seeks, truncates, and writes in ext4, shortening
or rejecting as appropriate.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>

Export iov_shorten() from kernel so that ext4 can
truncate too-large writes to bitmapped files.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>

use 2 different maxbytes functions for bitmapped & extent-based
files.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>

This patch converts ext4_inode i_blocks to represent total
blocks occupied by the inode in file system block size.
Earlier the variable used to represent this in 512 byte
block size. This actually limited the total size of the file.

The feature is enabled transparently when we write an inode
whose i_blocks cannot be represnted as 512 byte units in a
48 bit variable.

inode flag  EXT4_HUGE_FILE_FL
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Use the __le16 l_i_reserved1 field of the linux2 struct of ext4_inode
to represet the higher 16 bits for i_blocks. With this change max_file
size becomes (2**48 -1 )* 512 bytes.

We add a RO_COMPAT feature to the super block to indicate that inode
have i_blocks represented as a split 48 bits. Super block with this
feature set cannot be mounted read write on a kernel with CONFIG_LSF
disabled.

Super block flag EXT4_FEATURE_RO_COMPAT_HUGE_FILE
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Rename ext4_inode.i_dir_acl to i_size_high
drop ext4_inode_info.i_dir_acl as it is not used
Rename ext4_inode.i_size to ext4_inode.i_size_lo
Add helper function for accessing the ext4_inode combined i_size.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Rename i_file_acl to i_file_acl_lo. This helps
in finding bugs where we use i_file_acl instead
of the combined i_file_acl_lo and i_file_acl_high
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Fix sparse warnings related to static functions
and local variables.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Introduce ext4_update_*_feature and use them instead
of opencoding.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

This patch fixes various places where the group number is set to a negative
value.
Signed-off-by: Avantika Mathur <mathur@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

In many places variables for block group are of type int, which limits the
maximum number of block groups to 2^31.  Each block group can have up to
2^15 blocks, with a 4K block size,  and the max filesystem size is limited to
2^31 * (2^15 * 2^12) = 2^58  -- or 256 PB

This patch introduces a new type ext4_group_t, of type unsigned long, to
represent block group numbers in ext4.
All occurrences of block group variables are converted to type ext4_group_t.
Signed-off-by: Avantika Mathur <mathur@us.ibm.com>

There are many casts in extents.c which are not needed,
as the variables are already the type of the cast, or
are being promoted for no particular reason in printk's.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>

This patch adds a new data type ext4_lblk_t to represent
the logical file blocks.

This is the preparatory patch to support large files in ext4
The follow up patch with convert the ext4_inode i_blocks to
represent the number of blocks in file system block size. This
changes makes it possible to have a block number 2**32 -1 which
will result in overflow if the block number is represented by
signed long. This patch convert all the block number to type
ext4_lblk_t which is typedef to __u32

Also remove dead code ext4_ext_walk_space
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>

With 64KB blocksize, a directory entry can have size 64KB which does not fit
into 16 bits we have for entry lenght. So we store 0xffff instead and convert
value when read from / written to disk. The patch also converts some places
to use ext4_next_entry() when we are changing them anyway.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>

This patch set supports large block size(>4k, <=64k) in ext4,
just enlarging the block size limit. But it is NOT possible to have 64kB
blocksize on ext4 without some changes to the directory handling
code.  The reason is that an empty 64kB directory block would have a
rec_len == (__u16)2^16 == 0, and this would cause an error to be hit in
the filesystem.  The proposed solution is treat 64k rec_len
with a an impossible value like rec_len = 0xffff to handle this.

The Patch-set consists of the following 2 patches.
  [1/2]  ext4: enlarge blocksize
         - Allow blocksize up to pagesize

  [2/2]  ext4: fix rec_len overflow
         - prevent rec_len from overflow with 64KB blocksize

Now on 64k page ppc64 box runs with this patch set we could create a 64k
block size ext4dev, and able to handle empty directory block.
Signed-off-by: Takashi Sato <sho@tnes.nec.co.jp>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>

* git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog:
  [WATCHDOG] constify function pointer tables
  [WATCHDOG] TXx9 watchdog driver
  [WATCHDOG] misc_register patch	
  [WATCHDOG] wdt: fix locking

* git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6: (197 commits)
  sh: add spi header and r2d platform data V3
  sh: update r7780rp interrupt code
  sh: remove consistent alloc stuff from the machine vector
  sh: use declared coherent memory for dreamcast pci ethernet adapter
  sh: declared coherent memory support V2
  sh: Add support for SDK7780 board.
  sh: constify function pointer tables
  sh: Kill off -traditional for linker script.
  cdrom: Add support for Sega Dreamcast GD-ROM.
  sh: Kill off hs7751rvoip reference from arch/sh/Kconfig.
  sh: Drop r7780rp_defconfig, use r7780mp_defconfig as kbuild default.
  sh: Kill off dead HS771RVoIP board support.
  sh: r7785rp: Fix up DECLARE_INTC_DESC() arg mismatch.
  sh: r7785rp: Hook up the rest of the HL7785 FPGA IRQ vectors.
  sh: r2d - enable sm501 usb host function
  sh: remove voyagergx
  sh: r2d - add lcd planel timings to sm501 platform data
  sh: Add OHCI and UDC platform devices for SH7720.
  sh: intc - remove default interrupt priority tables
  sh: Correct pte size mismatch for X2 TLB.
  ...

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid: (24 commits)
  HID: ADS/Tech Radio si470x needs blacklist entry
  HID: Logitech Extreme 3D needs NOGET quirk
  HID: Refactor MS Presenter 8K key mapping
  HID: MS Presenter mapping for PID 0x0701
  HID: Support Samsung IR remote
  HID: fix compilation of hidbp drivers without usbhid
  HID: Blacklist the Gretag-Macbeth Huey display colorimeter
  HID: the `bit' in hidinput_mapping_quirks() is an out parameter
  HID: remove redundant WARN_ON()s in order not to scare users
  HID: force hiddev creation for SONY PS3 controller
  HID: Use hid blacklist in usbmouse/usbkbd
  HID: proper handling of MS 4k and 6k devices
  HID: remove unused variable in quirk event handler
  HID: hid-input quirk for BTC 8193
  HID: separate hid-input event quirks from generic code
  HID: refactor mapping to input subsystem for quirky devices
  HID: Microsoft Wireless Optical Desktop 3.0 quirk
  HID: Add support for Logitech Elite keyboards
  HID: add full support for Genius KB-29E
  HID: fix a potential bug in pointer casting
  ...

* 'for-2.6.25' of git://git.kernel.dk/linux-2.6-block:
  block: implement drain buffers
  __bio_clone: don't calculate hw/phys segment counts
  block: allow queue dma_alignment of zero
  blktrace: Add blktrace ioctls to SCSI generic devices

* 'blk-end-request' of git://git.kernel.dk/linux-2.6-block: (30 commits)
  blk_end_request: changing xsysace (take 4)
  blk_end_request: changing ub (take 4)
  blk_end_request: cleanup of request completion (take 4)
  blk_end_request: cleanup 'uptodate' related code (take 4)
  blk_end_request: remove/unexport end_that_request_* (take 4)
  blk_end_request: changing scsi (take 4)
  blk_end_request: add bidi completion interface (take 4)
  blk_end_request: changing ide-cd (take 4)
  blk_end_request: add callback feature (take 4)
  blk_end_request: changing ide normal caller (take 4)
  blk_end_request: changing cpqarray (take 4)
  blk_end_request: changing cciss (take 4)
  blk_end_request: changing ide-scsi (take 4)
  blk_end_request: changing s390 (take 4)
  blk_end_request: changing mmc (take 4)
  blk_end_request: changing i2o_block (take 4)
  blk_end_request: changing viocd (take 4)
  blk_end_request: changing xen-blkfront (take 4)
  blk_end_request: changing viodasd (take 4)
  blk_end_request: changing sx8 (take 4)
  ...

* 'sg' of git://git.kernel.dk/linux-2.6-block:
  SG: work with the SCSI fixed maximum allocations.
  SG: Convert SCSI to use scatterlist helpers for sg chaining
  SG: Move functions to lib/scatterlist.c and add sg chaining allocator helpers

* 'cfq-ioc-share' of git://git.kernel.dk/linux-2.6-block:
  cfq-iosched: kill some big inlines
  cfq-iosched: relax IOPRIO_CLASS_IDLE restrictions
  kernel: add CLONE_IO to specifically request sharing of IO contexts
  io_context sharing - anticipatory changes
  block: cfq: make the io contect sharing lockless
  io_context sharing - cfq changes
  io context sharing: preliminary support
  ioprio: move io priority from task_struct to io_context

* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (176 commits)
  [ARM] 4795/1: S3C244X: Add armclk and setparent call
  [ARM] 4794/1: S3C24XX: Comonise S3C2440 and S3C2442 clock code
  [ARM] 4793/1: S3C24XX: Add IRQ->GPIO pin mapping function
  [ARM] 4792/1: S3C24XX: Remove warnings from debug-macro.S
  [ARM] 4791/1: S3C2412: Make fclk a parent of msysclk
  [ARM] 4790/1: S3C2412: Fix parent selection for msysclk.
  [ARM] 4789/1: S3C2412: Add missing CLKDIVN register values
  [ARM] 4788/1: S3C24XX: Fix paramet to s3c2410_dma_ctrl if S3C2410_DMAF_AUTOSTART used.
  [ARM] 4787/1: S3C24XX: s3c2410_dma_request() should return the allocated channel number
  [ARM] 4786/1: S3C2412: Add SPI FIFO controll constants
  [ARM] 4785/1: S3C24XX: Add _SHIFT definitions for S3C2410_BANKCON registers
  [ARM] 4784/1: S3C24XX: Fix GPIO restore glitches
  [ARM] 4783/1: S3C24XX: Add s3c2410_gpio_getpull()
  [ARM] 4782/1: S3C24XX: Define FIQ_START for any FIQ users
  [ARM] 4781/1: S3C24XX: DMA suspend and resume support
  [ARM] 4780/1: S3C2412: Allow for seperate DMA channels for TX and RX
  [ARM] 4779/1: S3C2412: Add s3c2412_gpio_set_sleepcfg() call
  [ARM] 4778/1: S3C2412: Add armclk and init from DVS state
  [ARM] 4777/1: S3C24XX: Ensure clk_set_rate() checks the set_rate method for the clk
  [ARM] 4775/1: s3c2410: fix compilation error if only s3c2442 cpu is selected
  ...