The rec_len field in the directory entry is 16 bits, so to encode
blocksizes larger than 64k becomes problematic.  This patch allows us
to supprot block sizes up to 256k, by using the low 2 bits to extend
the range of rec_len to 2**18-1 (since valid rec_len sizes must be a
multiple of 4).  We use the convention that a rec_len of 0 or 65535
means the filesystem block size, for compatibility with older kernels.

It's unlikely we'll see VM pages of up to 256k, but at some point we
might find that the Linux VM has been enhanced to support filesystem
block sizes > than the VM page size, at which point it might be useful
for some applications to allow very large filesystem block sizes.
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Remove some leftovers from when the old block allocator was removed
(c2ea3fde).  ext4_sb_info is now a bit lighter.  Also remove a dangling
read_block_bitmap() prototype.
Signed-off-by: NMike Snitzer <snitzer@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

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>

The rec_len field in the directory entry is 16 bits, so there was a
problem representing rec_len for filesystems with a 64k block size in
the case where the directory entry takes the entire 64k block.
Unfortunately, there were two schemes that were proposed; one where
all zeros meant 65536 and one where all ones (65535) meant 65536.
E2fsprogs used 0, whereas the kernel used 65535.  Oops.  Fortunately
this case happens extremely rarely, with the most common case being
the lost+found directory, created by mke2fs.

So we will be liberal in what we accept, and accept both encodings,
but we will continue to encode 65536 as 65535.  This will require a
change in e2fsprogs, but with fortunately ext4 filesystems normally
have the dir_index feature enabled, which precludes having a
completely empty directory block.
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Directories are not allowed to be bigger than 2GB, so don't use
i_size_high for anything other than regular files.  E2fsck should
complain about these inodes, but the simplest thing to do for the
kernel is to only use i_size_high for regular files.

This prevents an intentially corrupted filesystem from causing the
kernel to burn a huge amount of CPU and issuing error messages such
as:

EXT4-fs warning (device loop0): ext4_block_to_path: block 135090028 > max

Thanks to David Maciejak from Fortinet's FortiGuard Global Security
Research Team for reporting this issue.

http://bugzilla.kernel.org/show_bug.cgi?id=12375Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org

For NR_CPUS >= 16 values, FBC_BATCH is 2*NR_CPUS

Considering more and more distros are using high NR_CPUS values, it makes
sense to use a more sensible value for FBC_BATCH, and get rid of NR_CPUS.

A sensible value is 2*num_online_cpus(), with a minimum value of 32 (This
minimum value helps branch prediction in __percpu_counter_add())

We already have a hotcpu notifier, so we can adjust FBC_BATCH dynamically.

We rename FBC_BATCH to percpu_counter_batch since its not a constant
anymore.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
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>

For uninit block group, the on-disk bitmap is not initialized. That
implies we cannot depend on the uptodate flag on the bitmap
buffer_head to find bitmap validity.  Use a new buffer_head flag which
would be set after we properly initialize the bitmap.  This also
prevents (re-)initializing the uninit group bitmap every time we call 
ext4_read_block_bitmap().
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org

Rename the lower bits with suffix _lo and add helper
to access the values. Also rename bg_itable_unused_hi
to bg_pad as in e2fsprogs.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The mballoc code likes to call ext4_error while it is holding locked
block groups.  This can causes a scheduling in atomic context BUG.  We
can't just unlock the block group and relock it after/if ext4_error
returns since that might result in race conditions in the case where
the filesystem is set to continue after finding errors.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The new groups added during resize are flagged as
need_init group. Make sure we properly initialize these
groups. When we have block size < page size and we are adding
new groups the page may still be marked uptodate even though
we haven't initialized the group. While forcing the init
of buddy cache we need to make sure other groups part of the
same page of buddy cache is not using the cache.
group_info->alloc_sem is added to ensure the same.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
cc: stable@kernel.org

With this change new blocks added during resize
are marked as free in the block bitmap and the
group is flagged with EXT4_GROUP_INFO_NEED_INIT_BIT
flag.  This makes sure when mballoc tries to allocate
blocks from the new group we would reload the
buddy information using the bitmap present in the disk.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org

* Change EXT4_HAS_*_FEATURE to return a boolean
* Add a function prototype for ext4_fiemap() in ext4.h
* Make ext4_ext_fiemap_cb() and ext4_xattr_fiemap() be static functions
* Add lock annotations to mb_free_blocks()
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Convert the unsigned longs that are most responsible for bloating the
stack usage on 64-bit systems.

Nearly all places in the ext3/4 code which uses "unsigned long" is
probably a bug, since on 32-bit systems a ulong a 32-bits, which means
we are wasting stack space on 64-bit systems.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Nearly all places in the ext3/4 code which uses "unsigned long" is
probably a bug, since on 32-bit systems a ulong a 32-bits, which means
we are wasting stack space on 64-bit systems.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Add new mount options, min_batch_time and max_batch_time, which
controls how long the jbd2 layer should wait for additional filesystem
operations to get batched with a synchronous write transaction.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

There were only two one callers of the function ext4_new_meta_block(),
which just a very simpler wrapper function around
ext4_new_meta_blocks().  Change those two functions to call
ext4_new_meta_blocks() directly, to save code and stack space usage.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

There was only one caller of the compatibility function
ext4_new_blocks(), in balloc.c's ext4_alloc_blocks().  Change it to
call ext4_mb_new_blocks() directly, and remove ext4_new_blocks()
altogether.  This cleans up the code, by removing two extra functions
from the call chain, and hopefully saving some stack usage.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The original ext3 hash algorithms assumed that variables of type char
were signed, as God and K&R intended.  Unfortunately, this assumption
is not true on some architectures.  Userspace support for marking
filesystems with non-native signed/unsigned chars was added two years
ago, but the kernel-side support was never added (until now).
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Mingming pointed out that ext4_claim_free_blocks & ext4_has_free_blocks
are largely cut & pasted; they can be collapsed/merged as follows.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Reviewed-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

These mount options don't actually do anything any more, so remove
them.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

If the journal doesn't abort when it gets an IO error in file data
blocks, the file data corruption will spread silently.  Because
most of applications and commands do buffered writes without fsync(),
they don't notice the IO error.  It's scary for mission critical
systems.  On the other hand, if the journal aborts whenever it gets
an IO error in file data blocks, the system will easily become
inoperable.  So this patch introduces a filesystem option to
determine whether it aborts the journal or just call printk() when
it gets an IO error in file data.

If you mount an ext4 fs with data_err=abort option, it aborts on file
data write error.  If you mount it with data_err=ignore, it doesn't
abort, just call printk().  data_err=ignore is the default.

Here is the corresponding patch of the ext3 version:
http://kerneltrap.org/mailarchive/linux-kernel/2008/9/9/3239374Signed-off-by: NHidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

ext4_ext_walk_space() was reinstated to be used for iterating over file
extents with a callback; it is used by the ext4 fiemap implementation.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: linux-ext4@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org

Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

With modern hard drives, reading 64k takes roughly the same time as
reading a 4k block.  So request readahead for adjacent inode table
blocks to reduce the time it takes when iterating over directories
(especially when doing this in htree sort order) in a cold cache case.
With this patch, the time it takes to run "git status" on a kernel
tree after flushing the caches via "echo 3 > /proc/sys/vm/drop_caches"
is reduced by 21%.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Previously mballoc created a separate set of functions for each proc
file.  This combines the tunables into a single set of functions which
gets used for all of the per-superblock proc files, saving
approximately 2k of compiled object code.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

...and into the core setup/teardown code in fs/ext4/super.c so that
other parts of ext4 can define tuning parameters.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Pick an ioctl number for EXT4_IOC_MIGRATE that won't conflict with
other ext4 ioctl's.  Since there haven't been any major userspace
users of this ioctl, we can afford to change this now, to avoid
potential problems later.

Also, reorder the ioctl numbers in ext4.h to avoid this sort of
mistake in the future.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This patch hooks the ext3 to ext4 migrate interface to
EXT4_IOC_SETFLAGS ioctl. The userspace interface is via chattr +e.  We
only allow setting extent flags.  Clearing extent flag (migrating from
ext4 to ext3) is not supported.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The migrate ioctl writes to the filsystem, so we need to elevate the
write count.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

With delayed allocation we use i_data_sem to update i_disksize.  We need
to update i_disksize only if the new size specified is greater than the
current value and we need to make sure we don't race with other
i_disksize update.  With delayed allocation we will switch to the
write_begin function for non-delayed allocation if we are low on free
blocks.  This means the write_begin function for non-delayed allocation
also needs to use the same locking.

We also need to check and update i_disksize even if the new size is less
that inode.i_size because of delayed allocation.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This patch converts some usage of ext4_fsblk_t to s64.  This is needed
so that some of the sign conversion works as expected in if loops.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

With delayed allocation we need to make sure block are reserved before
we attempt to allocate them. Otherwise we get block allocation failure
(ENOSPC) during writepages which cannot be handled. This would mean
silent data loss (We do a printk stating data will be lost). This patch
updates the DIO and fallocate code path to do block reservation before
block allocation. This is needed to make sure parallel DIO and fallocate
request doesn't take block out of delayed reserve space.

When free blocks count go below a threshold we switch to a slow patch
which looks at other CPU's accumulated percpu counter values.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

DIO and fallocate credit calculation is different than writepage, as
they do start a new journal right for each call to ext4_get_blocks_wrap().
This patch uses the helper function in DIO and fallocate case, passing
a flag indicating that the modified data are contigous thus could account
less indirect/index blocks.

This patch also fixed the journal credit reservation for direct I/O
(DIO).  Previously the estimated credits for DIO only was calculated for
non-extent files, which was not enough if the file is extent-based.

Also fixed was fallocate double-counting credits for modifying the the
superblock.
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

When considering how many journal credits are needed for modifying a
chunk of data, we need to account for the super block, inode block,
quota blocks and xattr block, indirect/index blocks, also, group bitmap
and group descriptor blocks for new allocation (including data and
indirect/index blocks). There are many places in ext4 do the calculation
on their own and often missed one or two meta blocks, and often they
assume single block allocation, and did not considering the multile
chunk of allocation case.

This patch is trying to cleanup current journal credit code, provides
some common helper funtion to calculate the journal credits, to be used
for writepage, writepages, DIO, fallocate, migration, defrag, and for
both nonextent and extent files.

This patch modified the writepage/write_begin credit caculation for
nonextent files, to use the new helper function. It also fixed the
problem that writepage on nonextent files did not consider the case
blocksize <pagesize, thus could possibelly need multiple block
allocation in a single transaction.
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The truncate patch should not use the i_allocated_meta_blocks
value. So add seperate functions to be used in the truncate
and alloc path. We also need to release the meta-data block
that we reserved for the blocks that we are truncating.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Right now i_blocks is not getting updated until the blocks are actually
allocaed on disk.  This means with delayed allocation, right after files
are copied, "ls -sF" shoes the file as taking 0 blocks on disk.  "du"
also shows the files taking zero space, which is highly confusing to the
user.

Since delayed allocation already keeps track of per-inode total
number of blocks that are subject to delayed allocation, this patch fix
this by using that to adjust the value returned by stat(2). When real
block allocation is done, the i_blocks will get updated. Since the
reserved blocks for delayed allocation will be decreased, this will be
keep value returned by stat(2) consistent.
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This patch does block reservation for delayed
allocation, to avoid ENOSPC later at page flush time.

Blocks(data and metadata) are reserved at da_write_begin()
time, the freeblocks counter is updated by then, and the number of
reserved blocks is store in per inode counter.
        
At the writepage time, the unused reserved meta blocks are returned
back. At unlink/truncate time, reserved blocks are properly released.

Updated fix from  Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
to fix the oldallocator block reservation accounting with delalloc, added
lock to guard the counters and also fix the reservation for meta blocks.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Updated with fixes from Mingming Cao <cmm@us.ibm.com> to unlock and
release the page from page cache if the delalloc write_begin failed, and
properly handle preallocated blocks.  Also added a fix to clear
buffer_delay in block_write_full_page() after allocating a delayed
buffer.

Updated with fixes from Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
to update i_disksize properly and to add bmap support for delayed
allocation.

Updated with a fix from Valerie Clement <valerie.clement@bull.net> to
avoid filesystem corruption when the filesystem is mounted with the
delalloc option and blocksize < pagesize.
Signed-off-by: NAlex Tomas <alex@clusterfs.com>
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: NDave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>