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: NAneesh 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: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NMingming 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: NEric Sandeen <sandeen@redhat.com>
Reviewed-by: NMingming Cao <cmm@us.ibm.com>

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

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: NEric Sandeen <sandeen@redhat.com>

use 2 different maxbytes functions for bitmapped & extent-based
files.
Signed-off-by: NEric 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: NAneesh 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: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

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

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

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: NAvantika Mathur <mathur@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: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: NEric Sandeen <sandeen@redhat.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: NTakashi Sato <sho@tnes.nec.co.jp>
Signed-off-by: NMingming Cao <cmm@us.ibm.com>

As it turns out, the kernel divides by EXT3_INODES_PER_GROUP(s) when
mounting an ext3 filesystem.  If that number is zero, a crash follows.
Below a patch.

This crash was reported by Joeri de Ruiter, Carst Tankink and Pim Vullers.

Cc: <linux-ext4@vger.kernel.org>
Acked-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now that nfsd has stopped writing to the find_exported_dentry member we an
mark the export_operations const
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Neil Brown <neilb@suse.de>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: <linux-ext4@vger.kernel.org>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Anton Altaparmakov <aia21@cantab.net>
Cc: David Chinner <dgc@sgi.com>
Cc: Timothy Shimmin <tes@sgi.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Chris Mason <mason@suse.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: "Vladimir V. Saveliev" <vs@namesys.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Trivial switch over to the new generic helpers.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Neil Brown <neilb@suse.de>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert s_r_blocks_count and s_free_blocks_count to
s_r_blocks_count_lo and s_free_blocks_count_lo

This helps in finding BUGs due to direct partial access of
these split 64 bit values

Also fix direct partial access in ext4 code
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Convert s_blocks_count to s_blocks_count_lo
This helps in finding BUGs due to direct partial access of
these split 64 bit values

Also fix direct partial access in ext4 code
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Convert bg_inode_bitmap and bg_inode_table to bg_inode_bitmap_lo
and bg_inode_table_lo.  This helps in finding BUGs due to
direct partial access of these split 64 bit values

Also fix one direct partial access
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Convert bg_block_bitmap to bg_block_bitmap_lo
This helps in catching some BUGS due to direct
partial access of these split fields.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

This feature relaxes check restrictions on where each block groups meta
data is located within the storage media.  This allows for the allocation
of bitmaps or inode tables outside the block group boundaries in cases
where bad blocks forces us to look for new blocks which the owning block
group can not satisfy.  This will also allow for new meta-data allocation
schemes to improve performance and scalability.
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>

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>

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>

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>

Replace n & (n - 1) with is_power_of_2(n)
Signed-off-by: Nvignesh babu <vignesh.babu@wipro.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It's *wrong* to have
			#define log2(n) ffz(~(n))
It should be *reversed*:
			#define log2(n) flz(~(n))
or
			#define log2(n) fls(n)
or just use
			ilog2(n) defined in linux/log2.h.

This patch follows the last solution, recommended by Andrew Morton.

Cc: <linux-ext4@vger.kernel.org>
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Chris Ahna <christopher.j.ahna@intel.com>
Cc: David Mosberger-Tang <davidm@hpl.hp.com>
Cc: Kyle McMartin <kyle@parisc-linux.org>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: NFengguang Wu <wfg@mail.ustc.edu.cn>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Slab constructors currently have a flags parameter that is never used.  And
the order of the arguments is opposite to other slab functions.  The object
pointer is placed before the kmem_cache pointer.

Convert

        ctor(void *object, struct kmem_cache *s, unsigned long flags)

to

        ctor(struct kmem_cache *s, void *object)

throughout the kernel

[akpm@linux-foundation.org: coupla fixes]
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

alloc_percpu can fail, propagate that error.
Signed-off-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>

 s/percpu_counter_sum/&_positive/

Because its consitent with percpu_counter_read*
Signed-off-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>

If we fail to start a transaction when releasing dquot, we have to call
dquot_release() anyway to mark dquot structure as inactive.  Otherwise we
end in an infinite loop inside dqput().
Signed-off-by: NJan Kara <jack@suse.cz>
Cc: xb <xavier.bru@bull.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

ext[234]_check_descriptors sanity checks block group descriptor geometry at
mount time, testing whether the block bitmap, inode bitmap, and inode table
reside wholly within the blockgroup.  However, the inode table test is off
by one so that if the last block in the inode table resides on the last
block of the block group, the test incorrectly fails.  This is because it
tests the last block as (start + length) rather than (start + length - 1).

This can be seen by trying to mount a filesystem made such as:

 mkfs.ext2 -F -b 1024 -m 0 -g 256 -N 3744 fsfile 1024

which yields:

 EXT2-fs error (device loop0): ext2_check_descriptors: Inode table for group 0 not in group (block 101)!
 EXT2-fs: group descriptors corrupted!

There is a similar bug in e2fsprogs, patch already sent for that.

(I wonder if inside(), outside(), and/or in_range() should someday be
used in this and other tests throughout the ext filesystems...)
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Slab destructors were no longer supported after Christoph's
c59def9f change. They've been
BUGs for both slab and slub, and slob never supported them
either.

This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Replace (n & (n-1)) in the context of power of 2 checks with
is_power_of_2()
Signed-off-by: NVignesh Babu <vignesh.babu@wipro.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This patch adds nanosecond timestamps for ext4. This involves adding
*time_extra fields to the ext4_inode to extend the timestamps to
64-bits.  Creation time is also added by this patch.

These extended fields will fit into an inode if the filesystem was
formatted with large inodes (-I 256 or larger) and there are currently
no EAs consuming all of the available space. For new inodes we always
reserve enough space for the kernel's known extended fields, but for
inodes created with an old kernel this might not have been the case. So
this patch also adds the EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE feature
flag(ro-compat so that older kernels can't create inodes with a smaller
extra_isize). which indicates if the fields fitting inside
s_min_extra_isize are available or not.  If the expansion of inodes if
unsuccessful then this feature will be disabled.  This feature is only
enabled if requested by the sysadmin.

None of the extended inode fields is critical for correct filesystem
operation.
Signed-off-by: NAndreas Dilger <adilger@clusterfs.com>
Signed-off-by: NKalpak Shah <kalpak@clusterfs.com>
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NDave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Set the journals JBD2_FEATURE_INCOMPAT_64BIT on devices with more
than 32bit block sizes during mount time.  This ensure proper record
lenth when writing to the journal.
Signed-off-by: NJose R. Santos <jrs@us.ibm.com>
Signed-off-by: NAndreas Dilger <adilger@clusterfs.com>
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: NLaurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Turn on extents feature by default in ext4 filesystem, to get wider
testing of extents feature in ext4dev.  This can be disabled using 
-o noextents.  
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

currently the export_operation structure and helpers related to it are in
fs.h.  fs.h is already far too large and there are very few places needing the
export bits, so split them off into a separate header.

[akpm@linux-foundation.org: fix cifs build]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNeil Brown <neilb@suse.de>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is a patch that speeds up statfs.  It is very simple - the "overhead"
calculation, which takes a huge amount of time for large filesystems, never
changes unless the size of the filesystem itself changes.  That means we can
store it in memory and only recalculate if the filesystem has been resized
(almost never).

It also fixes a minor problem that we never update the on-disk superblock free
blocks/inodes counts until the filesystem is unmounted.  While not fatal, we
may as well update that on disk when we have the information, and it makes
things like debugfs and dumpe2fs report a bit more accurate info.
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: NAndreas Dilger <adilger@clusterfs.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix error handling in ext4_create_journal according to kernel conventions.
Signed-off-by: NBorislav Petkov <bbpetkov@yahoo.de>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>