In pass1 of e2fsck, every inode table in the fileystem is scanned and checked,
regardless of whether it is in use.  This is this the most time consuming part
of the filesystem check.  The unintialized block group feature can greatly
reduce e2fsck time by eliminating checking of uninitialized inodes.

With this feature, there is a a high water mark of used inodes for each block
group.  Block and inode bitmaps can be uninitialized on disk via a flag in the
group descriptor to avoid reading or scanning them at e2fsck time.  A checksum
of each group descriptor is used to ensure that corruption in the group
descriptor's bit flags does not cause incorrect operation.

The feature is enabled through a mkfs option

	mke2fs /dev/ -O uninit_groups

A patch adding support for uninitialized block groups to e2fsprogs tools has
been posted to the linux-ext4 mailing list.

The patches have been stress tested with fsstress and fsx.  In performance
tests testing e2fsck time, we have seen that e2fsck time on ext3 grows
linearly with the total number of inodes in the filesytem.  In ext4 with the
uninitialized block groups feature, the e2fsck time is constant, based
solely on the number of used inodes rather than the total inode count.
Since typical ext4 filesystems only use 1-10% of their inodes, this feature can
greatly reduce e2fsck time for users.  With performance improvement of 2-20
times, depending on how full the filesystem is.

The attached graph shows the major improvements in e2fsck times in filesystems
with a large total inode count, but few inodes in use.

In each group descriptor if we have

EXT4_BG_INODE_UNINIT set in bg_flags:
        Inode table is not initialized/used in this group. So we can skip
        the consistency check during fsck.
EXT4_BG_BLOCK_UNINIT set in bg_flags:
        No block in the group is used. So we can skip the block bitmap
        verification for this group.

We also add two new fields to group descriptor as a part of
uninitialized group patch.

        __le16  bg_itable_unused;       /* Unused inodes count */
        __le16  bg_checksum;            /* crc16(sb_uuid+group+desc) */

bg_itable_unused:

If we have EXT4_BG_INODE_UNINIT not set in bg_flags
then bg_itable_unused will give the offset within
the inode table till the inodes are used. This can be
used by fsck to skip list of inodes that are marked unused.

bg_checksum:
Now that we depend on bg_flags and bg_itable_unused to determine
the block and inode usage, we need to make sure group descriptor
is not corrupt. We add checksum to group descriptor to
detect corruption. If the descriptor is found to be corrupt, we
mark all the blocks and inodes in the group used.
Signed-off-by: NAvantika Mathur <mathur@us.ibm.com>
Signed-off-by: NAndreas Dilger <adilger@clusterfs.com>
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

CONFIG_EXT4_INDEX is not an exposed config option in the kernel, and it is
unconditionally defined in ext4_fs.h.  tune2fs is already able to turn off
dir indexing, so at this point it's just cluttering up the code.  Remove
it.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

Fragment support in ext2/3/4 was never implemented, and it probably will
never be implemented.   So remove it from ext4.
Signed-off-by: NColy Li <coyli@suse.de>
Acked-by: NAndreas Dilger <adilger@clusterfs.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Mostly stolen from akpm's JBD cleanup patch.

- use `#ifdef foo' instead of `#if defined(foo)'

- Make journal_enable_debug __read_mostly just for the heck of it

- Make jbd_debugfs_dir and jbd_debug static

- debugfs_remove(NULL) is legal: remove unneeded tests

- remove unnecessary empty loops
Signed-off-by: NJose R. Santos <jrs@us.ibm.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

We should really call journal_abort() and not __journal_abort_hard() in
case of errors.  The latter call does not record the error in the journal
superblock and thus filesystem won't be marked as with errors later (and
user could happily mount it without any warning).
Signed-off-by: NJan Kara <jack@suse.cz>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

change JBD_XXX macros to JBD2_XXX in JBD2/Ext4
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Convert kmalloc to kzalloc() and get rid of the memset().
Signed-off-by: NMingming Cao <cmm@us.ibm.com>

This patch cleans up jbd_kmalloc and replace it with kmalloc directly
Signed-off-by: NMingming Cao <cmm@us.ibm.com>

This patch cleans up jbd_kmalloc and replace it with kmalloc directly
Signed-off-by: NMingming Cao <cmm@us.ibm.com>

JBD2: Replace slab allocations with page allocations

JBD2 allocate memory for committed_data and frozen_data from slab. However
JBD2 should not pass slab pages down to the block layer. Use page allocator
pages instead. This will also prepare JBD for the large blocksize patchset.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NMingming Cao <cmm@us.ibm.com>

JBD: Replace slab allocations with page allocations

JBD allocate memory for committed_data and frozen_data from slab. However
JBD should not pass slab pages down to the block layer. Use page allocator pages instead. This will also prepare JBD for the large blocksize patchset.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NMingming Cao <cmm@us.ibm.com>

* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6:
  [IA64] fix non-numa build

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  9p: remove sysctl
  9p: fix bad kconfig cross-dependency
  9p: soften invalidation in loose_mode
  9p: attach-per-user
  9p: rename uid and gid parameters
  9p: define session flags
  9p: Make transports dynamic

arch/ia64/kernel/machine_kexec.c: In function `arch_crash_save_vmcoreinfo':
arch/ia64/kernel/machine_kexec.c:131: error: `pgdat_list' undeclared (first use in this function)
arch/ia64/kernel/machine_kexec.c:131: error: (Each undeclared identifier is reported only once
arch/ia64/kernel/machine_kexec.c:131: error: for each function it appears in.)
arch/ia64/kernel/machine_kexec.c:134: error: `node_memblk' undeclared (first use in this function)
arch/ia64/kernel/machine_kexec.c:135: error: `NR_NODE_MEMBLKS' undeclared (first use in this function)
arch/ia64/kernel/machine_kexec.c:136: error: invalid application of `sizeof' to incomplete type `node_memblk_s'
arch/ia64/kernel/machine_kexec.c:137: error: dereferencing pointer to incomplete type
arch/ia64/kernel/machine_kexec.c:138: error: dereferencing pointer to incomplete type
make[1]: *** [arch/ia64/kernel/machine_kexec.o] Error 1
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NTony Luck <tony.luck@intel.com>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/drzeus/mmc:
  net: libertas sdio driver
  mmc: at91_mci: cleanup: use MCI_ERRORS
  mmc: possible leak in mmc_read_ext_csd

Add driver for Marvell's Libertas 8385 and 8686 wifi chips.
Signed-off-by: NPierre Ossman <drzeus@drzeus.cx>
Acked-by: NDan Williams <dcbw@redhat.com>

* ssh://master.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-x86: (114 commits)
  x86: delete vsyscall files during make clean
  kbuild: fix typo SRCARCH in find_sources
  x86: fix kernel rebuild due to vsyscall fallout
  .gitignore update for x86 arch
  x86: unify include/asm/debugreg_32/64.h
  x86: unify include/asm/unwind_32/64.h
  x86: unify include/asm/types_32/64.h
  x86: unify include/asm/tlb_32/64.h
  x86: unify include/asm/siginfo_32/64.h
  x86: unify include/asm/bug_32/64.h
  x86: unify include/asm/mman_32/64.h
  x86: unify include/asm/agp_32/64.h
  x86: unify include/asm/kdebug_32/64.h
  x86: unify include/asm/ioctls_32/64.h
  x86: unify include/asm/floppy_32/64.h
  x86: apply missing DMA/OOM prevention to floppy_32.h
  x86: unify include/asm/cache_32/64.h
  x86: unify include/asm/cache_32/64.h
  x86: unify include/asm/dmi_32/64.h
  x86: unify include/asm/delay_32/64.h
  ...

make clean failed to delete a few files in
x86/kernel. This is because kbuild does not
see the correct/full kernel/Makefile.

As a workaround until the Makefiles are merged specify
the files to be deleted in the common Makefile.

Reported by Mike Galbraith <efault@gmx.de>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

otherwise get the two copy file list in SRCARCH

for cscope:
C symbol: start_kernel

  File           Function            Line
0 proto.h        <global>              11 extern void start_kernel(void );
1 start_kernel.h <global>              10 extern asmlinkage void __init start_kernel(void );
2 head32.c       i386_start_kernel     37 start_kernel();
3 head32.c       i386_start_kernel     37 start_kernel();
4 head64.c       x86_64_start_kernel   85 start_kernel();
5 head64.c       x86_64_start_kernel   85 start_kernel();
6 head_32.S      options              199 cmpb $0,%cl #the first CPU calls start_kernel
7 head_32.S      options              199 cmpb $0,%cl #the first CPU calls start_kernel
8 enlighten.c    xen_start_kernel    1145 start_kernel();
9 enlighten.c    xen_start_kernel    1145 start_kernel();
a lguest.c       lguest_init         1095 start_kernel();
b main.c         start_kernel         513 asmlinkage void __init start_kernel(void )

after the patch:
C symbol: start_kernel

  File           Function            Line
0 proto.h        <global>              11 extern void start_kernel(void );
1 start_kernel.h <global>              10 extern asmlinkage void __init start_kernel(void );
2 head32.c       i386_start_kernel     37 start_kernel();
3 head64.c       x86_64_start_kernel   85 start_kernel();
4 head_32.S      options              199 cmpb $0,%cl #the first CPU calls start_kernel
5 enlighten.c    xen_start_kernel    1145 start_kernel();
6 lguest.c       lguest_init         1095 start_kernel();
7 main.c         start_kernel         513 asmlinkage void __init start_kernel(void )
Signed-off-by: NYinghai Lu <yinghai.lu@sun.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

A sysctl method was added to enable and disable debugging levels.  After
further review, it was decided that there are better approaches to doing this
and the sysctl methodology isn't really desirable.  This patch removes the
sysctl code from 9p.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>
  

A small MMC driver cleanup.

Use the defined AT91_MCI_ERRORS in at91_mci_completed_command() instead
of specifying all the error bits individually.
Signed-off-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: NPierre Ossman <drzeus@drzeus.cx>

The exception path associated with an invalid ext_csd_struct returns
without freeing ext_csd.

Coverity CID 1909.

Signed-off-by: Florin Malita
Signed-off-by: NPierre Ossman <drzeus@drzeus.cx>

This patch moves transport dynamic registration and matching to the net
module to prevent a bad Kconfig dependency between the net and fs 9p modules.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Loose mode in 9p utilizes the page cache without respecting coherency with
the server.  Any writes previously invaldiated the entire mapping for a file.
This patch softens the behavior to only invalidate the region of the actual
write.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

The 9P2000 protocol requires the authentication and permission checks to be
done in the file server. For that reason every user that accesses the file
server tree has to authenticate and attach to the server separately.
Multiple users can share the same connection to the server.

Currently v9fs does a single attach and executes all I/O operations as a
single user. This makes using v9fs in multiuser environment unsafe as it
depends on the client doing the permission checking.

This patch improves the 9P2000 support by allowing every user to attach
separately. The patch defines three modes of access (new mount option
'access'):

- attach-per-user (access=user) (default mode for 9P2000.u)
 If a user tries to access a file served by v9fs for the first time, v9fs
 sends an attach command to the server (Tattach) specifying the user. If
 the attach succeeds, the user can access the v9fs tree.
 As there is no uname->uid (string->integer) mapping yet, this mode works
 only with the 9P2000.u dialect.

- allow only one user to access the tree (access=<uid>)
 Only the user with uid can access the v9fs tree. Other users that attempt
 to access it will get EPERM error.

- do all operations as a single user (access=any) (default for 9P2000)
 V9fs does a single attach and all operations are done as a single user.
 If this mode is selected, the v9fs behavior is identical with the current
 one.
Signed-off-by: NLatchesar Ionkov <lucho@ionkov.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Change the names of 'uid' and 'gid' parameters to the more appropriate
'dfltuid' and 'dfltgid'.  This also sets the default uid/gid to -2
(aka nfsnobody)
Signed-off-by: NLatchesar Ionkov <lucho@ionkov.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Create more general flags field in the v9fs_session_info struct and move the
'extended' flag as a bit in the flags.
Signed-off-by: NLatchesar Ionkov <lucho@ionkov.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This patch abstracts out the interfaces to underlying transports so that
new transports can be added as modules.  This should also allow kernel
configuration of transports without ifdef-hell.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Fix rebuild of kernel when there is no changes.
This happened for i386.
Using make V=2 hinted that the output files were
not assigned to targets - fixed by this patch.

Reported by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This patch:
- makes .gitignore files visible to git
- makes arch/x86/kernel/vsyscall_32.lds and arch/i386/boot invisible
Signed-off-by: NDenis V. Lunev <den@openvz.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

* 'for-linus' of git://git.kernel.dk/data/git/linux-2.6-block:
  [BLOCK] blk_rq_map_sg() next_sg fixup
  Revert "[SCSI] Remove full sg table memset()"

Almost identical except for the extra DR_LEN_8 and the different
DR_CONTROL_RESERVED defines.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Conflicts:

	include/asm-x86/Kbuild

32bit has an extra UNW_FP define, which does not hurt.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Mostly the same. Make the few exceptions conditional.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Conflicts:

	include/asm-x86/types_32.h

Same file, except for whitespace, comment formatting.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Same file, except for the 64bit PREAMBLE_SIZE define.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Same file, except for whitespace, comment formatting and the
.long/.quad delta which can be solved by a define.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Same file, except for the extra 64bit MAP_32BIT define, which does not hurt
for 32 bit compiles.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The 32bit D(n) debug addon can be made exclusive for 32 bit compiles.
Otherwise all the same.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The 64 bit variant has additional function prototypes which do no harm
for 32 bit.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>