Cleanup of whitespace and formatting.  Initially driven by confusing indents
for the ext4_{block,inode}_bitmap() et. al. helper routines, but figured I'd
cleanup some other 80-column wrapping and other indenting problems at the
same time.
Signed-off-by: NAndreas Dilger <adilger@sun.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

If the caller isn't planning on modifying the block group descriptors,
there's no need to pass in a pointer to a struct buffer_head.  Nuking
this saves a tiny amount of CPU time and stack space usage.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Signed-off-by: NManish Katiyar <mkatiyar@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

To catch filesystem bugs or corruption which could lead to the
filesystem getting severly damaged, this patch adds a facility for
tracking all of the filesystem metadata blocks by contiguous regions
in a red-black tree.  This allows quick searching of the tree to
locate extents which might overlap with filesystem metadata blocks.

This facility is also used by the multi-block allocator to assure that
it is not allocating blocks out of the system zone, as well as by the
routines used when reading indirect blocks and extents information
from disk to make sure their contents are valid.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

We have sb_bgl_lock() and ext4_group_info.bb_state
bit spinlock to protech group information. The later is only
used within mballoc code. Consolidate them to use sb_bgl_lock().
This makes the mballoc.c code much simpler and also avoid
confusion with two locks protecting same info.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

In memory-constrained systems with many partitions, the ~68K for each
partition for the mb_history buffer can be excessive.

This patch adds a new mount option, mb_history_length, as well as a
way of setting the default via a module parameter (or via a sysfs
parameter in /sys/module/ext4/parameter/default_mb_history_length).
If the mb_history_length is set to zero, the mb_history facility is
disabled entirely.
Signed-off-by: NCurt Wohlgemuth <curtw@google.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Move the function prototypes in group.h into ext4.h so they are all
defined in one place.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The fs/ext4/namei.h header file had only a single function
declaration, and should have never been a standalone file.  Move it
into ext4.h, where should have been from the beginning.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

    
Use a separate lock to protect s_groups_count and the other block
group descriptors which get changed via an on-line resize operation,
so we can stop overloading the use of lock_super().
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Use a separate lock to protect the orphan list, so we can stop
overloading the use of lock_super().
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The function ext4_mark_recovery_complete() is called from two call
paths: either (a) while mounting the filesystem, in which case there's
no danger of any other CPU calling write_super() until the mount is
completed, and (b) while remounting the filesystem read-write, in
which case the fs core has already locked the superblock.  This also
allows us to take out a very vile unlock_super()/lock_super() pair in
ext4_remount().
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

ext4_fill_super() is no longer called by read_super(), and it is no
longer called with the superblock locked.  The
unlock_super()/lock_super() is no longer present, so this comment is
entirely superfluous.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Ext4's on-line resizing adds a new block group and then, only at the
last step adjusts s_groups_count.  However, it's possible on SMP
systems that another CPU could see the updated the s_group_count and
not see the newly initialized data structures for the just-added block
group.  For this reason, it's important to insert a SMP read barrier
after reading s_groups_count and before reading any (for example) the
new block group descriptors allowed by the increased value of
s_groups_count.

Unfortunately, we rather blatently violate this locking protocol
documented in fs/ext4/resize.c.  Fortunately, (1) on-line resizes
happen relatively rarely, and (2) it seems rare that the filesystem
code will immediately try to use just-added block group before any
memory ordering issues resolve themselves.  So apparently problems
here are relatively hard to hit, since ext3 has been vulnerable to the
same issue for years with no one apparently complaining.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

By using a separate super_operations structure for filesystems that
have and don't have journals, we can simply ext4_write_super() ---
which is only needed when no journal is present --- and ext4_freeze(),
ext4_unfreeze(), and ext4_sync_fs(), which are only needed when the
journal is present.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The s_dirt flag wasn't completely handled correctly, but it didn't
really matter when journalling was enabled.  It turns out that when
ext4 runs without a journal, we don't clear s_dirt in places where we
should have, with the result that the high-level write_super()
function was writing the superblock when it wasn't necessary.

So we fix this by making ext4_commit_super() clear the s_dirt flag,
and removing many of the other places where s_dirt is manipulated.
When journalling is enabled, the s_dirt flag might be left set more
often, but s_dirt really doesn't matter when journalling is enabled.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The ext4_commit_super() function took both a struct super_block * and
a struct ext4_super_block *, but the struct ext4_super_block can be
derived from the struct super_block.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Signed-off-by: NRobert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

For very large filesystems, the s_flex_groups array can get quite big.
For example, a filesystem that can be resized up to 16TB will have
8192 flex groups (assuming the default flex_bg size of 16), so the
array is 96k, which is *very* marginal for kmalloc().  On the other
hand, a 160GB filesystem without the resize_inode feature will only
require 960 bytes.  So we try to allocate the array first using
kmalloc(), and if that fails, we'll try to use vmalloc() instead.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Signed-off-by: NThiemo Nagel <thiemo.nagel@ph.tum.de>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Add support for using the mount options "barrier" and "nobarrier", and
"auto_da_alloc" and "noauto_da_alloc", which is more consistent than
"barrier=<0|1>" or "auto_da_alloc=<0|1>".  Most other ext3/ext4 mount
options use the foo/nofoo naming convention.  We allow the old forms
of these mount options for backwards compatibility.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Use lowercase names of quota functions instead of old uppercase ones.
Signed-off-by: NJan Kara <jack@suse.cz>
Acked-by: NMingming Cao <cmm@us.ibm.com>
CC: linux-ext4@vger.kernel.org

Uses quota reservation/claim/release to handle quota properly for delayed
allocation in the three steps: 1) quotas are reserved when data being copied
to cache when block allocation is defered 2) when new blocks are allocated.
reserved quotas are converted to the real allocated quota, 2) over-booked
quotas for metadata blocks are released back.
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Acked-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NJan Kara <jack@suse.cz>

ext4_dquot_initialize() and ext4_dquot_drop() is no longer
needed because of modified quota locking.
Signed-off-by: NJan Kara <jack@suse.cz>

Add a mount option which allows the user to disable automatic
allocation of blocks whose allocation by delayed allocation when the
file was originally truncated or when the file is renamed over an
existing file.  This feature is intended to save users from the
effects of naive application writers, but it reduces the effectiveness
of the delayed allocation code.  This mount option disables this
safety feature, which may be desirable for prodcutions systems where
the risk of unclean shutdowns or unexpected system crashes is low.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Instead of looping over all of the block groups in a flex group
summing their summary statistics, start tracking used_dirs in struct
flex_groups, and use struct flex_groups instead.  This should save a
bit of CPU for mkdir-heavy workloads.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Reduce pressure on the sb_bgl_lock family of locks by using atomic_t's
to track the number of free blocks and inodes in each flex_group.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Remove tuning knobs in /proc/fs/ext4/<dev/* since they have been
replaced by knobs in sysfs at /sys/fs/ext4/<dev>/*.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Add basic sysfs support so that information about the mounted
filesystem and various tuning parameters can be accessed via
/sys/fs/ext4/<dev>/*.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Add a new superblock value which tracks the lifetime amount of writes
to the filesystem.  This is useful in estimating the amount of wear on
solid state drives (SSD's) caused by writes to the filesystem.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Commit c4be0c1d added error checking to ext4_freeze() when calling
ext4_commit_super().  Unfortunately the patch failed to remove the
original call to ext4_commit_super(), with the net result that when
freezing the filesystem, the superblock gets written twice, the first
time without error checking.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

As spotted by kmemtrace, struct ext4_sb_info is 17664 bytes on 64-bit
which makes it a very bad fit for SLAB allocators.  The culprit of the
wasted memory is ->s_blockgroup_lock which can be as big as 16 KB when
NR_CPUS >= 32.

To fix that, allocate ->s_blockgroup_lock, which fits nicely in a order 2
page in the worst case, separately.  This shinks down struct ext4_sb_info
enough to fit a 2 KB slab cache so now we allocate 16 KB + 2 KB instead of
32 KB saving 14 KB of memory.
Acked-by: NAndreas Dilger <adilger@sun.com>
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This undoes commit 14ce0cb4.

Since jbd2_journal_start_commit() is now fixed to return 1 when we
started a transaction commit, there's some transaction waiting to be
committed or there's a transaction already committing, we don't
need to call ext4_force_commit() in ext4_sync_fs(). Furthermore
ext4_force_commit() can unnecessarily create sync transaction which is
expensive so it's worthwhile to remove it when we can.

http://bugzilla.kernel.org/show_bug.cgi?id=12224Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: linux-ext4@vger.kernel.org

Currently, ext3 in mainline Linux doesn't have the freeze feature which
suspends write requests.  So, we cannot take a backup which keeps the
filesystem's consistency with the storage device's features (snapshot and
replication) while it is mounted.

In many case, a commercial filesystem (e.g.  VxFS) has the freeze feature
and it would be used to get the consistent backup.

If Linux's standard filesystem ext3 has the freeze feature, we can do it
without a commercial filesystem.

So I have implemented the ioctls of the freeze feature.
I think we can take the consistent backup with the following steps.
1. Freeze the filesystem with the freeze ioctl.
2. Separate the replication volume or create the snapshot
   with the storage device's feature.
3. Unfreeze the filesystem with the unfreeze ioctl.
4. Take the backup from the separated replication volume
   or the snapshot.

This patch:

VFS:
Changed the type of write_super_lockfs and unlockfs from "void"
to "int" so that they can return an error.
Rename write_super_lockfs and unlockfs of the super block operation
freeze_fs and unfreeze_fs to avoid a confusion.

ext3, ext4, xfs, gfs2, jfs:
Changed the type of write_super_lockfs and unlockfs from "void"
to "int" so that write_super_lockfs returns an error if needed,
and unlockfs always returns 0.

reiserfs:
Changed the type of write_super_lockfs and unlockfs from "void"
to "int" so that they always return 0 (success) to keep a current behavior.
Signed-off-by: NTakashi Sato <t-sato@yk.jp.nec.com>
Signed-off-by: NMasayuki Hamaguchi <m-hamaguchi@ys.jp.nec.com>
Cc: <xfs-masters@oss.sgi.com>
Cc: <linux-ext4@vger.kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This mount option is largely superfluous, and in fact the way it was
implemented was buggy; if a filesystem which did not have the extents
feature flag was mounted -o extents, the filesystem would attempt to
create and use extents-based file even though the extents feature flag
was not eabled.  The simplest thing to do is to nuke the mount option
entirely.  It's not all that useful to force the non-creation of new
extent-based files if the filesystem can support it.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Previously, some were "ext4: ", and some were "EXT4: "; change them to
be consistent with most ext4 printk's, which is to use "EXT4-fs: ".
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This avoids insane superblock configurations that could lead to kernel
oops due to null pointer derefences.

http://bugzilla.kernel.org/show_bug.cgi?id=12371

Thanks to David Maciejak at Fortinet's FortiGuard Global Security
Research Team who discovered this bug independently (but at
approximately the same time) as Thiemo Nagel, who submitted the patch.
Signed-off-by: NThiemo Nagel <thiemo.nagel@ph.tum.de>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org

Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: Jens Axboe <jens.axboe@oracle.com>

Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NMark Fasheh <mfasheh@suse.com>

Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NMark Fasheh <mfasheh@suse.com>

This code has been obsolete in quite some time, since the supported
method for adding a journal inode is to use tune2fs (or to creating
new filesystem with a journal via mke2fs or mkfs.ext4).
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>