btrfs: ref-verify: free ref cache before clearing mount opt

As clearing REF_VERIFY mount option indicates there were some errors in a
ref-verify process, a ref cache is not relevant anymore and should be
freed.

btrfs_free_ref_cache() requires REF_VERIFY option being set so call
it just before clearing the mount option.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Reported-by: syzbot+be14ed7728594dc8bd42@syzkaller.appspotmail.com
Fixes: fd708b81d972 ("Btrfs: add a extent ref verify tool")
CC: stable@vger.kernel.org # 5.4+
Closes: https://lore.kernel.org/lkml/000000000000e5a65c05ee832054@google.com/
Reported-by: syzbot+c563a3c79927971f950f@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/0000000000007fe09705fdc6086c@google.com/
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: ref-verify: fix memory leaks in btrfs_ref_tree_mod()

In btrfs_ref_tree_mod(), when !parent 're' was allocated through
kmalloc(). In the following code, if an error occurs, the execution will
be redirected to 'out' or 'out_unlock' and the function will be exited.
However, on some of the paths, 're' are not deallocated and may lead to
memory leaks.

For example: lookup_block_entry() for 'be' returns NULL, the out label
will be invoked. During that flow ref and 'ra' are freed but not 're',
which can potentially lead to a memory leak.

CC: stable@vger.kernel.org # 5.10+
Reported-and-tested-by: syzbot+d66de4cbf532749df35f@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=d66de4cbf532749df35f
Signed-off-by: Bragatheswaran Manickavel <bragathemanick0908@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: new inline ref storing owning subvol of data extents

In order to implement simple quota groups, we need to be able to
associate a data extent with the subvolume that created it. Once you
account for reflink, this information cannot be recovered without
explicitly storing it. Options for storing it are:

- a new key/item
- a new extent inline ref item

The former is backwards compatible, but wastes space, the latter is
incompat, but is efficient in space and reuses the existing inline ref
machinery, while only abusing it a tiny amount -- specifically, the new
item is not a ref, per-se.

Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: rename tree_ref and data_ref owning_root

commit 113479d5b8eb ("btrfs: rename root fields in delayed refs structs")
changed these from ref_root to owning_root. However, there are many
circumstances where that name is not really accurate and the root on the
ref struct _is_ the referring root. In general, these are not the owning
root, though it does happen in some ref merging cases involving
overwrites during snapshots and similar.

Simple quotas cares quite a bit about tracking the original owner of an
extent through delayed refs, so rename these back to free up the name
for the real owning root (which will live on the generic btrfs_ref and
the head ref)

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: reformat remaining kdoc style comments

Function name in the comment does not bring much value to code not
exposed as API and we don't stick to the kdoc format anymore. Update
formatting of parameter descriptions.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: move accessor helpers into accessors.h

This is a large patch, but because they're all macros it's impossible to
split up. Simply copy all of the item accessors in ctree.h and paste
them in accessors.h, and then update any files to include the header so
everything compiles.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ reformat comments, style fixups ]
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: move mount option definitions to fs.h

These are fs wide definitions and helpers, move them out of ctree.h and
into fs.h.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: move the printk helpers out of ctree.h

We have a bunch of printk helpers that are in ctree.h. These have
nothing to do with ctree.c, so move them into their own header.
Subsequent patches will cleanup the printk helpers.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: stop accessing ->extent_root directly

When we start having multiple extent roots we'll need to use a helper to
get to the correct extent_root. Rename fs_info->extent_root to
_extent_root and convert all of the users of the extent root to using
the btrfs_extent_root() helper. This will allow us to easily clean up
the remaining direct accesses in the future.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: drop the _nr from the item helpers

Now that all call sites are using the slot number to modify item values,
rename the SETGET helpers to raw_item_*(), and then rework the _nr()
helpers to be the btrfs_item_*() btrfs_set_item_*() helpers, and then
rename all of the callers to the new helpers.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: rename root fields in delayed refs structs

Both data and metadata delayed ref structures have fields named
root/ref_root respectively. Those are somewhat cryptic and don't really
convey the real meaning. In fact those roots are really the original
owners of the respective block (i.e in case of a snapshot a data delayed
ref will contain the original root that owns the given block). Rename
those fields accordingly and adjust comments.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: stop doing GFP_KERNEL memory allocations in the ref verify tool

In commit 351cbf6e4410e7 ("btrfs: use nofs allocations for running delayed
items") we wrapped all btree updates when running delayed items with
memalloc_nofs_save() and memalloc_nofs_restore(), due to a lock inversion
detected by lockdep involving reclaim and the mutex of delayed nodes.

The problem is because the ref verify tool does some memory allocations
with GFP_KERNEL, which can trigger reclaim and reclaim can trigger inode
eviction, which requires locking the mutex of an inode's delayed node.
On the other hand the ref verify tool is called when allocating metadata
extents as part of operations that modify a btree, which is a problem when
running delayed nodes, where we do btree updates while holding the mutex
of a delayed node. This is what caused the lockdep warning.

Instead of wrapping every btree update when running delayed nodes, change
the ref verify tool to never do GFP_KERNEL allocations, because:

1) We get less repeated code, which at the moment does not even have a
comment mentioning why we need to setup the NOFS context, which is a
recommended good practice as mentioned at
Documentation/core-api/gfp_mask-from-fs-io.rst

2) The ref verify tool is something meant only for debugging and not
something that should be enabled on non-debug / non-development
kernels;

3) We may have yet more places outside delayed-inode.c where we have
similar problem: doing btree updates while holding some lock and
then having the GFP_KERNEL memory allocations, from the ref verify
tool, trigger reclaim and trying again to acquire the same lock
through the reclaim path.
Or we could get more such cases in the future, therefore this change
prevents getting into similar cases when using the ref verify tool.

Curiously most of the memory allocations done by the ref verify tool
were already using GFP_NOFS, except a few ones for no apparent reason.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: ref-verify: use 'inline void' keyword ordering

Fix build warnings of function signature when CONFIG_STACKTRACE is not
enabled by reordering the 'inline' and 'void' keywords.

../fs/btrfs/ref-verify.c:221:1: warning: ‘inline’ is not at beginning of declaration [-Wold-style-declaration]
static void inline __save_stack_trace(struct ref_action *ra)
../fs/btrfs/ref-verify.c:225:1: warning: ‘inline’ is not at beginning of declaration [-Wold-style-declaration]
static void inline __print_stack_trace(struct btrfs_fs_info *fs_info,

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: ref-verify: make sure owner is set for all refs

I noticed that shared ref entries in ref-verify didn't have the proper
owner set, which caused me to think there was something seriously wrong.
However the problem is if we have a parent we simply weren't filling out
the owner part of the reference, even though we have it.

Fix this by making sure we set all the proper fields when we modify a
reference, this way we'll have the proper owner if a problem happens and
we don't waste time thinking we're updating the wrong level.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: ref-verify: pass down tree block level when building refs

I noticed that sometimes I would have the wrong level printed out with
ref-verify while testing some error injection related problems. This is
because we only get the level from the main extent item, but our
references could go off the current leaf into another, and at that point
we lose our level.

Fix this by keeping track of the last tree block level that we found,
the same way we keep track of our bytenr and num_bytes, in case we
happen to wander into another leaf while still processing the references
for a bytenr.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: use btrfs_read_node_slot in walk_down_tree

We're open-coding btrfs_read_node_slot() here, replace with the helper.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: locking: remove all the blocking helpers

Now that we're using a rw_semaphore we no longer need to indicate if a
lock is blocking or not, nor do we need to flip the entire path from
blocking to spinning. Remove these helpers and all the places they are
called.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: remove unnecessary casts in printk

Long time ago the explicit casts were necessary for u64 but we don't
need it. Remove casts where the type matches, leaving only cases that
cast sector_t or loff_t.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: ref-verify: fix memory leak in btrfs_ref_tree_mod

There is one error handling path that does not free ref, which may cause
a minor memory leak.

CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: ref-verify: fix memory leak in add_block_entry

clang static analysis flags this error

fs/btrfs/ref-verify.c:290:3: warning: Potential leak of memory pointed to by 're' [unix.Malloc]
kfree(be);
^~~~~

The problem is in this block of code:

if (root_objectid) {
struct root_entry *exist_re;

exist_re = insert_root_entry(&exist->roots, re);
if (exist_re)
kfree(re);
}

There is no 'else' block freeing when root_objectid is 0. Add the
missing kfree to the else branch.

Fixes: fd708b81d972 ("Btrfs: add a extent ref verify tool")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: convert comments to fallthrough annotations

Convert fall through comments to the pseudo-keyword which is now the
preferred way.

Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: fix ref-verify to catch operations on 0 ref extents

While debugging I noticed I wasn't getting ref verify errors before
everything blew up. Turns out it's because we don't warn when we try to
add a normal ref via btrfs_inc_ref() if the block entry exists but has 0
references. This is incorrect, we should never be doing anything other
than adding a new extent once a block entry drops to 0 references.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: ref-verify: fix memory leaks

In btrfs_ref_tree_mod(), 'ref' and 'ra' are allocated through kzalloc() and
kmalloc(), respectively. In the following code, if an error occurs, the
execution will be redirected to 'out' or 'out_unlock' and the function will
be exited. However, on some of the paths, 'ref' and 'ra' are not
deallocated, leading to memory leaks. For example, if 'action' is
BTRFS_ADD_DELAYED_EXTENT, add_block_entry() will be invoked. If the return
value indicates an error, the execution will be redirected to 'out'. But,
'ref' is not deallocated on this path, causing a memory leak.

To fix the above issues, deallocate both 'ref' and 'ra' before exiting from
the function when an error is encountered.

CC: stable@vger.kernel.org # 4.15+
Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: fix uninitialized ret in ref-verify

Coverity caught a case where we could return with a uninitialized value
in ret in process_leaf. This is actually pretty likely because we could
very easily run into a block group item key and have a garbage value in
ret and think there was an errror. Fix this by initializing ret to 0.

Reported-by: Colin Ian King <colin.king@canonical.com>
Fixes: fd708b81d972 ("Btrfs: add a extent ref verify tool")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: ref-verify: Use btrfs_ref to refactor btrfs_ref_tree_mod()

It's a perfect match for btrfs_ref_tree_mod() to use btrfs_ref, as
btrfs_ref describes a metadata/data reference update comprehensively.

Now we have one less function use confusing owner/level trick.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: ref-verify: Simplify stack trace retrieval

Replace the indirection through struct stack_trace with an invocation of
the storage array based interface.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: David Sterba <dsterba@suse.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: linux-btrfs@vger.kernel.org
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: linux-mm@kvack.org
Cc: David Rientjes <rientjes@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: kasan-dev@googlegroups.com
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: iommu@lists.linux-foundation.org
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: dm-devel@redhat.com
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: David Airlie <airlied@linux.ie>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: linux-arch@vger.kernel.org
Link: https://lkml.kernel.org/r/20190425094802.338890064@linutronix.de

fs: mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

This patch fixes the following warnings:

fs/affs/affs.h:124:38: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/configfs/dir.c:1692:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/configfs/dir.c:1694:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/ceph/file.c:249:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/ext4/hash.c:233:15: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/ext4/hash.c:246:15: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/ext2/inode.c:1237:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/ext2/inode.c:1244:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/ext4/indirect.c:1182:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/ext4/indirect.c:1188:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/ext4/indirect.c:1432:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/ext4/indirect.c:1440:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/f2fs/node.c:618:8: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/f2fs/node.c:620:8: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/btrfs/ref-verify.c:522:15: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/gfs2/bmap.c:711:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/gfs2/bmap.c:722:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/jffs2/fs.c:339:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/nfsd/nfs4proc.c:429:12: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/ufs/util.h:62:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/ufs/util.h:43:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/fcntl.c:770:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/seq_file.c:319:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/libfs.c:148:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/libfs.c:150:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/signalfd.c:178:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
fs/locks.c:1473:16: warning: this statement may fall through [-Wimplicit-fallthrough=]

Warning level 3 was used: -Wimplicit-fallthrough=3

This patch is part of the ongoing efforts to enabling
-Wimplicit-fallthrough.

Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

btrfs: replace btrfs_set_lock_blocking_rw with appropriate helpers

We can use the right helper where the lock type is a fixed parameter.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: Fix typos in comments and strings

The typos accumulate over time so once in a while time they get fixed in
a large patch.

Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: Remove 'objectid' member from struct btrfs_root

There are two members in struct btrfs_root which indicate root's
objectid: objectid and root_key.objectid.

They are both set to the same value in __setup_root():

static void __setup_root(struct btrfs_root *root,
struct btrfs_fs_info *fs_info,
u64 objectid)
{
...
root->objectid = objectid;
...
root->root_key.objectid = objecitd;
...
}

and not changed to other value after initialization.

grep in btrfs directory shows both are used in many places:
$ grep -rI "root->root_key.objectid" | wc -l
133
$ grep -rI "root->objectid" | wc -l
55
(4.17, inc. some noise)

It is confusing to have two similar variable names and it seems
that there is no rule about which should be used in a certain case.

Since ->root_key itself is needed for tree reloc tree, let's remove
'objecitd' member and unify code to use ->root_key.objectid in all places.

Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: replace GPL boilerplate by SPDX -- sources

Remove GPL boilerplate text (long, short, one-line) and keep the rest,
ie. personal, company or original source copyright statements. Add the
SPDX header.

Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: Validate child tree block's level and first key

We have several reports about node pointer points to incorrect child
tree blocks, which could have even wrong owner and level but still with
valid generation and checksum.

Although btrfs check could handle it and print error message like:
leaf parent key incorrect 60670574592

Kernel doesn't have enough check on this type of corruption correctly.
At least add such check to read_tree_block() and btrfs_read_buffer(),
where we need two new parameters @level and @first_key to verify the
child tree block.

The new @level check is mandatory and all call sites are already
modified to extract expected level from its call chain.

While @first_key is optional, the following call sites are skipping such
check:
1) Root node/leaf
As ROOT_ITEM doesn't contain the first key, skip @first_key check.
2) Direct backref
Only parent bytenr and level is known and we need to resolve the key
all by ourselves, skip @first_key check.

Another note of this verification is, it needs extra info from nodeptr
or ROOT_ITEM, so it can't fit into current tree-checker framework, which
is limited to node/leaf boundary.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: ref-verify: Remove unused parameter from walk_up_tree() to kill warning

With gcc-4.1.2:

fs/btrfs/ref-verify.c: In function ‘btrfs_build_ref_tree’:
fs/btrfs/ref-verify.c:1017: warning: ‘root’ is used uninitialized in this function

The variable is indeed passed uninitialized, but it is never used by the
callee. However, not all versions of gcc are smart enough to notice.

Hence remove the unused parameter from walk_up_tree() to silence the
compiler warning.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David Sterba <dsterba@suse.com>

Btrfs: add a extent ref verify tool

We were having corruption issues that were tied back to problems with
the extent tree. In order to track them down I built this tool to try
and find the culprit, which was pretty successful. If you compile with
this tool on it will live verify every ref update that the fs makes and
make sure it is consistent and valid. I've run this through with
xfstests and haven't gotten any false positives. Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update error messages, add fixup from Dan Carpenter to handle errors
of read_tree_block ]
Signed-off-by: David Sterba <dsterba@suse.com>