Switch ext4 to using sb_getblk_gfp with GFP_NOFS added to fix possible
deadlocks in the page writeback path.
Signed-off-by: NNikolay Borisov <kernel@kyup.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

In order to prevent quota block tracking to be inaccurate when
ext4_quota_write() fails with ENOSPC, we make two changes.  The quota
file can now use the reserved block (since the quota file is arguably
file system metadata), and ext4_quota_write() now uses
ext4_should_retry_alloc() to retry the block allocation after a commit
has completed and released some blocks for allocation.

This fixes failures of xfstests generic/270:

Quota error (device vdc): write_blk: dquota write failed
Quota error (device vdc): qtree_write_dquot: Error -28 occurred while creating quota
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Currently existing dio workers can jump in and potentially increase
extent tree depth while we're allocating blocks in
ext4_alloc_file_blocks().  This may cause us to underestimate the
number of credits needed for the transaction because the extent tree
depth can change after our estimation.

Fix this by waiting for all the existing dio workers in the same way
as we do it in ext4_punch_hole.  We've seen errors caused by this in
xfstest generic/299, however it's really hard to reproduce.
Signed-off-by: NLukas Czerner <lczerner@redhat.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Currently in ext4_alloc_file_blocks() the number of credits is
calculated only once before we enter the allocation loop. However within
the allocation loop the extent tree depth can change, hence the number
of credits needed can increase potentially exceeding the number of credits
reserved in the handle which can cause journal failures.

Fix this by recalculating number of credits when the inode depth
changes. Note that even though ext4_alloc_file_blocks() is only
currently used by extent base inodes we will avoid recalculating number
of credits unnecessarily in the case of indirect based inodes.
Signed-off-by: NLukas Czerner <lczerner@redhat.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

This patch implements fallocate's FALLOC_FL_INSERT_RANGE for Ext4.

1) Make sure that both offset and len are block size aligned.
2) Update the i_size of inode by len bytes.
3) Compute the file's logical block number against offset. If the computed
   block number is not the starting block of the extent, split the extent
   such that the block number is the starting block of the extent.
4) Shift all the extents which are lying between [offset, last allocated extent]
   towards right by len bytes. This step will make a hole of len bytes
   at offset.
Signed-off-by: NNamjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: NAshish Sangwan <a.sangwan@samsung.com>

During a source code review of fs/ext4/extents.c I noted identical
consecutive lines. An assertion is repeated for inode1 and never done
for inode2. This is not in keeping with the rest of the code in the
ext4_swap_extents function and appears to be a bug.

Assert that the inode2 mutex is not locked.
Signed-off-by: NDavid Moore <dmoorefo@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NEric Sandeen <sandeen@redhat.com>

With the planned cgroup writeback support, backing-dev related
declarations will be more widely used across block and cgroup;
unfortunately, including backing-dev.h from include/linux/blkdev.h
makes cyclic include dependency quite likely.

This patch separates out backing-dev-defs.h which only has the
essential definitions and updates blkdev.h to include it.  c files
which need access to more backing-dev details now include
backing-dev.h directly.  This takes backing-dev.h off the common
include dependency chain making it a lot easier to use it across block
and cgroup.

v2: fs/fat build failure fixed.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reviewed-by: NJan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NJens Axboe <axboe@fb.com>

The xfstests test suite assumes that an attempt to collapse range on
the range (0, 1) will return EOPNOTSUPP if the file system does not
support collapse range.  Commit 280227a7: "ext4: move check under
lock scope to close a race" broke this, and this caused xfstests to
fail when run when testing file systems that did not have the extents
feature enabled.
Reported-by: NEric Whitney <enwlinux@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

The following commit introduced a bug when checking for zero length extent

5946d089 ext4: check for overlapping extents in ext4_valid_extent_entries()

Zero length extent could pass the check if lblock is zero.

Adding the explicit check for zero length back.
Signed-off-by: NEryu Guan <guaneryu@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

fallocate() checks that the file is extent-based and returns
EOPNOTSUPP in case is not. Other tasks can convert from and to
indirect and extent so it's safe to check only after grabbing
the inode mutex.
Signed-off-by: NDavide Italiano <dccitaliano@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

Pulls block_write_begin() into fs/ext4/inode.c because it might need
to do a low-level read of the existing data, in which case we need to
decrypt it.
Signed-off-by: NMichael Halcrow <mhalcrow@google.com>
Signed-off-by: NIldar Muslukhov <ildarm@google.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

When xfstests' auto group is run on a bigalloc filesystem with a
4.0-rc3 kernel, e2fsck failures and kernel warnings occur for some
tests. e2fsck reports incorrect iblocks values, and the warnings
indicate that the space reserved for delayed allocation is being
overdrawn at allocation time.

Some of these errors occur because the reserved space is incorrectly
decreased by one cluster when ext4_ext_map_blocks satisfies an
allocation request by mapping an unused portion of a previously
allocated cluster.  Because a cluster's worth of reserved space was
already released when it was first allocated, it should not be released
again.

This patch appears to correct the e2fsck failure reported for
generic/232 and the kernel warnings produced by ext4/001, generic/009,
and generic/033.  Failures and warnings for some other tests remain to
be addressed.
Signed-off-by: NEric Whitney <enwlinux@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

In ext4_zero_range(), removing a file's entire block range from the
extent status tree removes all records of that file's delalloc extents.
The delalloc accounting code uses this information, and its loss can
then lead to accounting errors and kernel warnings at writeback time and
subsequent file system damage.  This is most noticeable on bigalloc
file systems where code in ext4_ext_map_blocks() handles cases where
delalloc extents share clusters with a newly allocated extent.

Because we're not deleting a block range and are correctly updating the
status of its associated extent, there is no need to remove anything
from the extent status tree.

When this patch is combined with an unrelated bug fix for
ext4_zero_range(), kernel warnings and e2fsck errors reported during
xfstests runs on bigalloc filesystems are greatly reduced without
introducing regressions on other xfstests-bld test scenarios.
Signed-off-by: NEric Whitney <enwlinux@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Currently there is a bug in zero range code which causes zero range
calls to only allocate block aligned portion of the range, while
ignoring the rest in some cases.

In some cases, namely if the end of the range is past i_size, we do
attempt to preallocate the last nonaligned block. However this might
cause kernel to BUG() in some carefully designed zero range requests
on setups where page size > block size.

Fix this problem by first preallocating the entire range, including
the nonaligned edges and converting the written extents to unwritten
in the next step. This approach will also give us the advantage of
having the range to be as linearly contiguous as possible.
Signed-off-by: NLukas Czerner <lczerner@redhat.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Since commit a9b82415, we are allowed to merge unwritten extents,
so here these comments are wrong, remove it.
Signed-off-by: NXiaoguang Wang <wangxg.fnst@cn.fujitsu.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

This reverts commit 14516bb7.

This was causing regression test failures with generic/285 with an ext3
filesystem using CONFIG_EXT4_USE_FOR_EXT23.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

It is ridiculous practice to scan inode block by block, this technique
applicable only for old indirect files. This takes significant amount
of time for really large files. Let's reuse ext4_fiemap which already
traverse inode-tree in most optimal meaner.

TESTCASE:
ftruncate64(fd, 0);
ftruncate64(fd, 1ULL << 40);
/* lseek will spin very long time */
lseek64(fd, 0, SEEK_DATA);
lseek64(fd, 0, SEEK_HOLE);

Original report: https://lkml.org/lkml/2014/10/16/620Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Currently ext4_inline_data_fiemap ignores requested arguments (start
and len) which may lead endless loop if start != 0.  Also fix incorrect
extent length determination.
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

path[depth].p_hdr can never be NULL for a path passed to us (and even if
it could, EXT_LAST_EXTENT() would make something != NULL from it). So
just remove the branch.

Coverity-id: 1196498
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Currently callers adding extents to extent status tree were responsible
for adding the inode to the list of inodes with freeable extents. This
is error prone and puts list handling in unnecessarily many places.

Just add inode to the list automatically when the first non-delay extent
is added to the tree and remove inode from the list when the last
non-delay extent is removed.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

In this commit we discard the lru algorithm for inodes with extent
status tree because it takes significant effort to maintain a lru list
in extent status tree shrinker and the shrinker can take a long time to
scan this lru list in order to reclaim some objects.

We replace the lru ordering with a simple round-robin.  After that we
never need to keep a lru list.  That means that the list needn't be
sorted if the shrinker can not reclaim any objects in the first round.

Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Signed-off-by: NZheng Liu <wenqing.lz@taobao.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Currently extent status tree doesn't cache extent hole when a write
looks up in extent tree to make sure whether a block has been allocated
or not.  In this case, we don't put extent hole in extent cache because
later this extent might be removed and a new delayed extent might be
added back.  But it will cause a defect when we do a lot of writes.  If
we don't put extent hole in extent cache, the following writes also need
to access extent tree to look at whether or not a block has been
allocated.  It brings a cache miss.  This commit fixes this defect.
Also if the inode doesn't have any extent, this extent hole will be
cached as well.

Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Signed-off-by: NZheng Liu <wenqing.lz@taobao.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

For bigalloc filesystems we have to check whether newly requested inode
block isn't already part of a cluster for which we already have delayed
allocation reservation. This check happens in ext4_ext_map_blocks() and
that function sets EXT4_MAP_FROM_CLUSTER if that's the case. However if
ext4_da_map_blocks() finds in extent cache information about the block,
we don't call into ext4_ext_map_blocks() and thus we always end up
getting new reservation even if the space for cluster is already
reserved. This results in overreservation and premature ENOSPC reports.

Fix the problem by checking for existing cluster reservation already in
ext4_da_map_blocks(). That simplifies the logic and actually allows us
to get rid of the EXT4_MAP_FROM_CLUSTER flag completely.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

ext4_ext_remove_space() can incorrectly free a partial_cluster if
EAGAIN is encountered while truncating or punching.  Extent removal
should be retried in this case.

It also fails to free a partial cluster when the punched region begins
at the start of a file on that unaligned cluster and where the entire
file has not been punched.  Remove the requirement that all blocks in
the file must have been freed in order to free the partial cluster.
Signed-off-by: NEric Whitney <enwlinux@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Add some casts and rearrange a few statements for improved readability.
Some code can also be simplified and made more readable if we set
partial_cluster to 0 rather than to a negative value when we can tell
we've hit the left edge of the punched region.
Signed-off-by: NEric Whitney <enwlinux@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

The fix in commit ad6599ab ("ext4: fix premature freeing of
partial clusters split across leaf blocks"), intended to avoid
dereferencing an invalid extent pointer when determining whether a
partial cluster should be freed, wasn't quite good enough.  Assure that
at least one extent remains at the start of the leaf once the hole has
been punched.  Otherwise, the pointer to the extent to the right of the
hole will be invalid and a partial cluster will be incorrectly freed.

Set partial_cluster to 0 when we can tell we've hit the left edge of
the punched region within the leaf.  This prevents incorrect freeing
of a partial cluster when ext4_ext_rm_leaf is called one last time
during extent tree traversal after the punched region has been removed.

Adjust comments to reflect code changes and a correction.  Remove a bit
of dead code.
Signed-off-by: NEric Whitney <enwlinux@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

The partial_cluster variable is not always initialized correctly when
hole punching on bigalloc file systems.  Although commit c0634493
("ext4: fix partial cluster handling for bigalloc file systems")
addressed the case where the right edge of the punched region and the
next extent to its right were within the same leaf, it didn't handle
the case where the next extent to its right is in the next leaf.  This
causes xfstest generic/300 to fail.

Fix this by replacing the code in c0634493922 with a more general
solution that can continue the search for the first cluster to the
right of the punched region into the next leaf if present.  If found,
partial_cluster is initialized to this cluster's negative value.
There's no need to determine if that cluster is actually shared;  we
simply record it so its blocks won't be freed in the event it does
happen to be shared.

Also, minimize the burden on non-bigalloc file systems with some minor
code simplification.
Signed-off-by: NEric Whitney <enwlinux@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

ext4_ext_convert_to_initialized() can return more blocks than are
actually allocated from map->m_lblk in case where initial part of the
on-disk extent is zeroed out. Luckily this doesn't have serious
consequences because the caller currently uses the return value
only to unmap metadata buffers. Anyway this is a data
corruption/exposure problem waiting to happen so fix it.

Coverity-id: 1226848
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Besides the fact that this replacement improves code readability
it also protects from errors caused direct EXT4_S(sb)->s_es manipulation
which may result attempt to use uninitialized  csum machinery.

#Testcase_BEGIN
IMG=/dev/ram0
MNT=/mnt
mkfs.ext4 $IMG
mount $IMG $MNT
#Enable feature directly on disk, on mounted fs
tune2fs -O metadata_csum  $IMG
# Provoke metadata update, likey result in OOPS
touch $MNT/test
umount $MNT
#Testcase_END

# Replacement script
@@
expression E;
@@
- EXT4_HAS_RO_COMPAT_FEATURE(E, EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)
+ ext4_has_metadata_csum(E)

https://bugzilla.kernel.org/show_bug.cgi?id=82201Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

It is reasonable to prepend newly created index to older one.

[ Dropped no longer used function parameter newext. -tytso ]
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

The EXT4_STATE_DELALLOC_RESERVED flag was originally implemented
because it was too hard to make sure the mballoc and get_block flags
could be reliably passed down through all of the codepaths that end up
calling ext4_mb_new_blocks().

Since then, we have mb_flags passed down through most of the code
paths, so getting rid of EXT4_STATE_DELALLOC_RESERVED isn't as tricky
as it used to.

This commit plumbs in the last of what is required, and then adds a
WARN_ON check to make sure we haven't missed anything.  If this passes
a full regression test run, we can then drop
EXT4_STATE_DELALLOC_RESERVED.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NJan Kara <jack@suse.cz>

Make the function name less redundant.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Now that the semantics of ext4_ext_find_extent() are much cleaner,
it's safe and more efficient to reuse the path object across the
multiple calls to ext4_ext_find_extent() in ext4_ext_shift_extents().
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

This adds additional safety in case for some reason we end reusing a
path structure which isn't big enough for current depth of the inode.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Teach ext4_ext_drop_refs() to accept a NULL argument, much like
kfree().  This allows us to drop a lot of checks to make sure path is
non-NULL before calling ext4_ext_drop_refs().
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

In nearly all of the calls to ext4_ext_find_extent() where the caller
is trying to recycle the path object, ext4_ext_drop_refs() gets called
to release the buffer heads before the path object gets overwritten.
To simplify things for the callers, and to avoid the possibility of a
memory leak, make ext4_ext_find_extent() responsible for dropping the
buffers.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Drop EXT4_EX_NOFREE_ON_ERR from ext4_ext_create_new_leaf(),
ext4_split_extent(), ext4_convert_unwritten_extents_endio().

This requires fixing all of their callers to potentially
ext4_ext_find_extent() to free the struct ext4_ext_path object in case
of an error, and there are interlocking dependencies all the way up to
ext4_ext_map_blocks(), ext4_swap_extents(), and
ext4_ext_remove_space().

Once this is done, we can drop the EXT4_EX_NOFREE_ON_ERR flag since it
is no longer necessary.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Transfer responsibility of freeing struct ext4_ext_path on error to
ext4_ext_find_extent().
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

The function ext4_convert_initialized_extents() is only called by a
single function --- ext4_ext_convert_initalized_extents().  Inline the
code and get rid of the unnecessary bits in order to simplify the code.

Rename ext4_ext_convert_initalized_extents() to
convert_initalized_extents() since it's a static function that is
actually only used in a single caller, ext4_ext_map_blocks().
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Right now, there are a places where it is all to easy to leak memory
on an error path, via a usage like this:

	struct ext4_ext_path *path = NULL

	while (...) {
		...
		path = ext4_ext_find_extent(inode, block, path, 0);
		if (IS_ERR(path)) {
			/* oops, if path was non-NULL before the call to
			   ext4_ext_find_extent, we've leaked it!  :-(  */
			...
			return PTR_ERR(path);
		}
		...
	}

Unfortunately, there some code paths where we are doing the following
instead:

	path = ext4_ext_find_extent(inode, block, orig_path, 0);

and where it's important that we _not_ free orig_path in the case
where ext4_ext_find_extent() returns an error.

So change the function signature of ext4_ext_find_extent() so that it
takes a struct ext4_ext_path ** for its third argument, and by
default, on an error, it will free the struct ext4_ext_path, and then
zero out the struct ext4_ext_path * pointer.  In order to avoid
causing problems, we add a flag EXT4_EX_NOFREE_ON_ERR which causes
ext4_ext_find_extent() to use the original behavior of forcing the
caller to deal with freeing the original path pointer on the error
case.

The goal is to get rid of EXT4_EX_NOFREE_ON_ERR entirely, but this
allows for a gentle transition and makes the patches easier to verify.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>