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There's an unnecessary indirection in the checksum definition table,
pointer and the string itself. The strings are short and the overall
size of one entry is now 24 bytes.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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All callers pass extent buffer start and length so the extent buffer
itself should work fine.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The helpers are related to locking so move them there, update comments.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Each new element added to the mod seq list is always appended to the list,
and each one gets a sequence number coming from a counter which gets
incremented everytime a new element is added to the list (or a new node
is added to the tree mod log rbtree). Therefore the element with the
lowest sequence number is always the first element in the list.
So just remove the list iteration at btrfs_put_tree_mod_seq() that
computes the minimum sequence number in the list and replace it with
a check for the first element's sequence number.
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>
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There is a race between adding and removing elements to the tree mod log
list and rbtree that can lead to use-after-free problems.
Consider the following example that explains how/why the problems happens:
1) Task A has mod log element with sequence number 200. It currently is
the only element in the mod log list;
2) Task A calls btrfs_put_tree_mod_seq() because it no longer needs to
access the tree mod log. When it enters the function, it initializes
'min_seq' to (u64)-1. Then it acquires the lock 'tree_mod_seq_lock'
before checking if there are other elements in the mod seq list.
Since the list it empty, 'min_seq' remains set to (u64)-1. Then it
unlocks the lock 'tree_mod_seq_lock';
3) Before task A acquires the lock 'tree_mod_log_lock', task B adds
itself to the mod seq list through btrfs_get_tree_mod_seq() and gets a
sequence number of 201;
4) Some other task, name it task C, modifies a btree and because there
elements in the mod seq list, it adds a tree mod elem to the tree
mod log rbtree. That node added to the mod log rbtree is assigned
a sequence number of 202;
5) Task B, which is doing fiemap and resolving indirect back references,
calls btrfs get_old_root(), with 'time_seq' == 201, which in turn
calls tree_mod_log_search() - the search returns the mod log node
from the rbtree with sequence number 202, created by task C;
6) Task A now acquires the lock 'tree_mod_log_lock', starts iterating
the mod log rbtree and finds the node with sequence number 202. Since
202 is less than the previously computed 'min_seq', (u64)-1, it
removes the node and frees it;
7) Task B still has a pointer to the node with sequence number 202, and
it dereferences the pointer itself and through the call to
__tree_mod_log_rewind(), resulting in a use-after-free problem.
This issue can be triggered sporadically with the test case generic/561
from fstests, and it happens more frequently with a higher number of
duperemove processes. When it happens to me, it either freezes the VM or
it produces a trace like the following before crashing:
[ 1245.321140] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
[ 1245.321200] CPU: 1 PID: 26997 Comm: pool Not tainted 5.5.0-rc6-btrfs-next-52 #1
[ 1245.321235] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
[ 1245.321287] RIP: 0010:rb_next+0x16/0x50
[ 1245.321307] Code: ....
[ 1245.321372] RSP: 0018:ffffa151c4d039b0 EFLAGS: 00010202
[ 1245.321388] RAX: 6b6b6b6b6b6b6b6b RBX: ffff8ae221363c80 RCX: 6b6b6b6b6b6b6b6b
[ 1245.321409] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff8ae221363c80
[ 1245.321439] RBP: ffff8ae20fcc4688 R08: 0000000000000002 R09: 0000000000000000
[ 1245.321475] R10: ffff8ae20b120910 R11: 00000000243f8bb1 R12: 0000000000000038
[ 1245.321506] R13: ffff8ae221363c80 R14: 000000000000075f R15: ffff8ae223f762b8
[ 1245.321539] FS: 00007fdee1ec7700(0000) GS:ffff8ae236c80000(0000) knlGS:0000000000000000
[ 1245.321591] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1245.321614] CR2: 00007fded4030c48 CR3: 000000021da16003 CR4: 00000000003606e0
[ 1245.321642] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1245.321668] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1245.321706] Call Trace:
[ 1245.321798] __tree_mod_log_rewind+0xbf/0x280 [btrfs]
[ 1245.321841] btrfs_search_old_slot+0x105/0xd00 [btrfs]
[ 1245.321877] resolve_indirect_refs+0x1eb/0xc60 [btrfs]
[ 1245.321912] find_parent_nodes+0x3dc/0x11b0 [btrfs]
[ 1245.321947] btrfs_check_shared+0x115/0x1c0 [btrfs]
[ 1245.321980] ? extent_fiemap+0x59d/0x6d0 [btrfs]
[ 1245.322029] extent_fiemap+0x59d/0x6d0 [btrfs]
[ 1245.322066] do_vfs_ioctl+0x45a/0x750
[ 1245.322081] ksys_ioctl+0x70/0x80
[ 1245.322092] ? trace_hardirqs_off_thunk+0x1a/0x1c
[ 1245.322113] __x64_sys_ioctl+0x16/0x20
[ 1245.322126] do_syscall_64+0x5c/0x280
[ 1245.322139] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 1245.322155] RIP: 0033:0x7fdee3942dd7
[ 1245.322177] Code: ....
[ 1245.322258] RSP: 002b:00007fdee1ec6c88 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 1245.322294] RAX: ffffffffffffffda RBX: 00007fded40210d8 RCX: 00007fdee3942dd7
[ 1245.322314] RDX: 00007fded40210d8 RSI: 00000000c020660b RDI: 0000000000000004
[ 1245.322337] RBP: 0000562aa89e7510 R08: 0000000000000000 R09: 00007fdee1ec6d44
[ 1245.322369] R10: 0000000000000073 R11: 0000000000000246 R12: 00007fdee1ec6d48
[ 1245.322390] R13: 00007fdee1ec6d40 R14: 00007fded40210d0 R15: 00007fdee1ec6d50
[ 1245.322423] Modules linked in: ....
[ 1245.323443] ---[ end trace 01de1e9ec5dff3cd ]---
Fix this by ensuring that btrfs_put_tree_mod_seq() computes the minimum
sequence number and iterates the rbtree while holding the lock
'tree_mod_log_lock' in write mode. Also get rid of the 'tree_mod_seq_lock'
lock, since it is now redundant.
Fixes: bd989ba359f2ac ("Btrfs: add tree modification log functions")
Fixes: 097b8a7c9e48e2 ("Btrfs: join tree mod log code with the code holding back delayed refs")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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When a tree mod log user no longer needs to use the tree it calls
btrfs_put_tree_mod_seq() to remove itself from the list of users and
delete all no longer used elements of the tree's red black tree, which
should be all elements with a sequence number less then our equals to
the caller's sequence number. However the logic is broken because it
can delete and free elements from the red black tree that have a
sequence number greater then the caller's sequence number:
1) At a point in time we have sequence numbers 1, 2, 3 and 4 in the
tree mod log;
2) The task which got assigned the sequence number 1 calls
btrfs_put_tree_mod_seq();
3) Sequence number 1 is deleted from the list of sequence numbers;
4) The current minimum sequence number is computed to be the sequence
number 2;
5) A task using sequence number 2 is at tree_mod_log_rewind() and gets
a pointer to one of its elements from the red black tree through
a call to tree_mod_log_search();
6) The task with sequence number 1 iterates the red black tree of tree
modification elements and deletes (and frees) all elements with a
sequence number less then or equals to 2 (the computed minimum sequence
number) - it ends up only leaving elements with sequence numbers of 3
and 4;
7) The task with sequence number 2 now uses the pointer to its element,
already freed by the other task, at __tree_mod_log_rewind(), resulting
in a use-after-free issue. When CONFIG_DEBUG_PAGEALLOC=y it produces
a trace like the following:
[16804.546854] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
[16804.547451] CPU: 0 PID: 28257 Comm: pool Tainted: G W 5.4.0-rc8-btrfs-next-51 #1
[16804.548059] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
[16804.548666] RIP: 0010:rb_next+0x16/0x50
(...)
[16804.550581] RSP: 0018:ffffb948418ef9b0 EFLAGS: 00010202
[16804.551227] RAX: 6b6b6b6b6b6b6b6b RBX: ffff90e0247f6600 RCX: 6b6b6b6b6b6b6b6b
[16804.551873] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff90e0247f6600
[16804.552504] RBP: ffff90dffe0d4688 R08: 0000000000000001 R09: 0000000000000000
[16804.553136] R10: ffff90dffa4a0040 R11: 0000000000000000 R12: 000000000000002e
[16804.553768] R13: ffff90e0247f6600 R14: 0000000000001663 R15: ffff90dff77862b8
[16804.554399] FS: 00007f4b197ae700(0000) GS:ffff90e036a00000(0000) knlGS:0000000000000000
[16804.555039] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[16804.555683] CR2: 00007f4b10022000 CR3: 00000002060e2004 CR4: 00000000003606f0
[16804.556336] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[16804.556968] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[16804.557583] Call Trace:
[16804.558207] __tree_mod_log_rewind+0xbf/0x280 [btrfs]
[16804.558835] btrfs_search_old_slot+0x105/0xd00 [btrfs]
[16804.559468] resolve_indirect_refs+0x1eb/0xc70 [btrfs]
[16804.560087] ? free_extent_buffer.part.19+0x5a/0xc0 [btrfs]
[16804.560700] find_parent_nodes+0x388/0x1120 [btrfs]
[16804.561310] btrfs_check_shared+0x115/0x1c0 [btrfs]
[16804.561916] ? extent_fiemap+0x59d/0x6d0 [btrfs]
[16804.562518] extent_fiemap+0x59d/0x6d0 [btrfs]
[16804.563112] ? __might_fault+0x11/0x90
[16804.563706] do_vfs_ioctl+0x45a/0x700
[16804.564299] ksys_ioctl+0x70/0x80
[16804.564885] ? trace_hardirqs_off_thunk+0x1a/0x20
[16804.565461] __x64_sys_ioctl+0x16/0x20
[16804.566020] do_syscall_64+0x5c/0x250
[16804.566580] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[16804.567153] RIP: 0033:0x7f4b1ba2add7
(...)
[16804.568907] RSP: 002b:00007f4b197adc88 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[16804.569513] RAX: ffffffffffffffda RBX: 00007f4b100210d8 RCX: 00007f4b1ba2add7
[16804.570133] RDX: 00007f4b100210d8 RSI: 00000000c020660b RDI: 0000000000000003
[16804.570726] RBP: 000055de05a6cfe0 R08: 0000000000000000 R09: 00007f4b197add44
[16804.571314] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4b197add48
[16804.571905] R13: 00007f4b197add40 R14: 00007f4b100210d0 R15: 00007f4b197add50
(...)
[16804.575623] ---[ end trace 87317359aad4ba50 ]---
Fix this by making btrfs_put_tree_mod_seq() skip deletion of elements that
have a sequence number equals to the computed minimum sequence number, and
not just elements with a sequence number greater then that minimum.
Fixes: bd989ba359f2ac ("Btrfs: add tree modification log functions")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Add blake2b (with 256 bit digest) to the list of possible checksumming
algorithms used by BTRFS.
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently all the checksum algorithms generate a fixed size digest size
and we use it. The on-disk format can hold up to BTRFS_CSUM_SIZE bytes
and BLAKE2b produces digest of 512 bits by default. We can't do that and
will use the blake2b-256, this needs to be passed to the crypto API.
Separate that from the base algorithm name and add a member to request
specific driver, in this case with the digest size.
The only place that uses the driver name is the crypto API setup.
Signed-off-by: David Sterba <dsterba@suse.com>
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Export supported checksum algorithms via sysfs in the list of static
features:
/sys/fs/btrfs/features/supported_checksums
Space spearated list of checksum algorithm names.
Co-developed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>
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Add sha256 to the list of possible checksumming algorithms used by BTRFS.
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Add xxhash64 to the list of possible checksumming algorithms used by
BTRFS.
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The helper is trivial and we can understand what the atomic_inc on
something named refs does.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The attribute is more relaxed than const and the functions could
dereference pointers, as long as the observable state is not changed. We
do have such functions, based on -Wsuggest-attribute=pure .
The visible effects of this patch are negligible, there are differences
in the assembly but hard to summarize.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The function belongs to the family of locking functions, so move it
there. The 'noinline' keyword is dropped as it's now an exported
function that does not need it.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The function belongs to the family of locking functions, so move it
there. The 'noinline' keyword is dropped as it's now an exported
function that does not need it.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The following comment shows up in btrfs_search_slot() with out much
sense:
/*
* setup the path here so we can release it under lock
* contention with the cow code
*/
if (cow) {
/* code touching path->lock[] is far away from here */
}
This comment hasn't been cleaned up after the relevant code has been
removed.
The original code is introduced in commit 65b51a009e29
("btrfs_search_slot: reduce lock contention by cowing in two stages"):
+
+ /*
+ * setup the path here so we can release it under lock
+ * contention with the cow code
+ */
+ p->nodes[level] = b;
+ if (!p->skip_locking)
+ p->locks[level] = 1;
+
But in current code, we have different timing for modifying path lock,
so just remove the comment.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Similar to btrfs_search_slot() done in previous patch, make a shortcut
for the level 0 case and allow to reduce indentation for the remaining
case.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
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In btrfs_search_slot(), we something like:
if (level != 0) {
/* Do search inside tree nodes*/
} else {
/* Do search inside tree leaves */
goto done;
}
This caused extra indent for tree node search code. Change it to
something like:
if (level == 0) {
/* Do search inside tree leaves */
goto done'
}
/* Do search inside tree nodes */
So we have more space to maneuver our code, this is especially useful as
the tree nodes search code is more complex than the leaves search code.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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btrfs_try_tree_write_lock/btrfs_tree_read_lock_atomic
Those function are simple boolean predicates there is no need to assign
their return values to interim variables. Use them directly as
predicates. No functional changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Create a structure to encode the type and length for the known on-disk
checksums. This makes it easier to add new checksums later.
The structure and helpers are moved from ctree.h so they don't occupy
space in all headers including ctree.h. This save some space in the
final object.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Further simplifaction of the get/set helpers is possible when the token
is uniquely tied to an extent buffer. A condition and an assignment can
be avoided.
The initializations are moved closer to the first use when the extent
buffer is valid. There's one exception in __push_leaf_left where the
token is reused.
Signed-off-by: David Sterba <dsterba@suse.com>
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Send is the only user of tree_compare, we can move it there along with
the other helpers and definitions.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>
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Preparatory work for code that will be moved out of ctree and uses this
function.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>
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At ctree.c:get_old_root(), we are accessing a root's header owner field
after we have freed the respective extent buffer. This results in an
use-after-free that can lead to crashes, and when CONFIG_DEBUG_PAGEALLOC
is set, results in a stack trace like the following:
[ 3876.799331] stack segment: 0000 [#1] SMP DEBUG_PAGEALLOC PTI
[ 3876.799363] CPU: 0 PID: 15436 Comm: pool Not tainted 5.3.0-rc3-btrfs-next-54 #1
[ 3876.799385] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
[ 3876.799433] RIP: 0010:btrfs_search_old_slot+0x652/0xd80 [btrfs]
(...)
[ 3876.799502] RSP: 0018:ffff9f08c1a2f9f0 EFLAGS: 00010286
[ 3876.799518] RAX: ffff8dd300000000 RBX: ffff8dd85a7a9348 RCX: 000000038da26000
[ 3876.799538] RDX: 0000000000000000 RSI: ffffe522ce368980 RDI: 0000000000000246
[ 3876.799559] RBP: dae1922adadad000 R08: 0000000008020000 R09: ffffe522c0000000
[ 3876.799579] R10: ffff8dd57fd788c8 R11: 000000007511b030 R12: ffff8dd781ddc000
[ 3876.799599] R13: ffff8dd9e6240578 R14: ffff8dd6896f7a88 R15: ffff8dd688cf90b8
[ 3876.799620] FS: 00007f23ddd97700(0000) GS:ffff8dda20200000(0000) knlGS:0000000000000000
[ 3876.799643] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3876.799660] CR2: 00007f23d4024000 CR3: 0000000710bb0005 CR4: 00000000003606f0
[ 3876.799682] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 3876.799703] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 3876.799723] Call Trace:
[ 3876.799735] ? do_raw_spin_unlock+0x49/0xc0
[ 3876.799749] ? _raw_spin_unlock+0x24/0x30
[ 3876.799779] resolve_indirect_refs+0x1eb/0xc80 [btrfs]
[ 3876.799810] find_parent_nodes+0x38d/0x1180 [btrfs]
[ 3876.799841] btrfs_check_shared+0x11a/0x1d0 [btrfs]
[ 3876.799870] ? extent_fiemap+0x598/0x6e0 [btrfs]
[ 3876.799895] extent_fiemap+0x598/0x6e0 [btrfs]
[ 3876.799913] do_vfs_ioctl+0x45a/0x700
[ 3876.799926] ksys_ioctl+0x70/0x80
[ 3876.799938] ? trace_hardirqs_off_thunk+0x1a/0x20
[ 3876.799953] __x64_sys_ioctl+0x16/0x20
[ 3876.799965] do_syscall_64+0x62/0x220
[ 3876.799977] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 3876.799993] RIP: 0033:0x7f23e0013dd7
(...)
[ 3876.800056] RSP: 002b:00007f23ddd96ca8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 3876.800078] RAX: ffffffffffffffda RBX: 00007f23d80210f8 RCX: 00007f23e0013dd7
[ 3876.800099] RDX: 00007f23d80210f8 RSI: 00000000c020660b RDI: 0000000000000003
[ 3876.800626] RBP: 000055fa2a2a2440 R08: 0000000000000000 R09: 00007f23ddd96d7c
[ 3876.801143] R10: 00007f23d8022000 R11: 0000000000000246 R12: 00007f23ddd96d80
[ 3876.801662] R13: 00007f23ddd96d78 R14: 00007f23d80210f0 R15: 00007f23ddd96d80
(...)
[ 3876.805107] ---[ end trace e53161e179ef04f9 ]---
Fix that by saving the root's header owner field into a local variable
before freeing the root's extent buffer, and then use that local variable
when needed.
Fixes: 30b0463a9394d9 ("Btrfs: fix accessing the root pointer in tree mod log functions")
CC: stable@vger.kernel.org # 3.10+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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extent-tree.c has a find_next_key that just walks up the path to find
the next key, but it is used for both the caching stuff and the snapshot
delete stuff. The snapshot deletion stuff is special so it can't really
use btrfs_find_next_key, but the caching thread stuff can. We just need
to fix btrfs_find_next_key to deal with ->skip_locking and then it works
exactly the same as the private find_next_key helper.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The tree is going to be modified so it must be the exclusive lock.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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We have a long standing problem with reversed keys that's detected by
btrfs_set_item_key_safe. This is hard to reproduce so we'd like to
capture more information for later analysis.
Let's dump the leaf content before triggering BUG_ON() so that we can
have some clue on what's going wrong. The output of tree locks should
help us to debug such problem.
Sample stacktrace:
generic/522 [00:07:05]
[26946.113381] run fstests generic/522 at 2019-04-16 00:07:05
[27161.474720] kernel BUG at fs/btrfs/ctree.c:3192!
[27161.475923] invalid opcode: 0000 [#1] PREEMPT SMP
[27161.477167] CPU: 0 PID: 15676 Comm: fsx Tainted: G W 5.1.0-rc5-default+ #562
[27161.478932] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c89-prebuilt.qemu.org 04/01/2014
[27161.481099] RIP: 0010:btrfs_set_item_key_safe+0x146/0x1c0 [btrfs]
[27161.485369] RSP: 0018:ffffb087499e39b0 EFLAGS: 00010286
[27161.486464] RAX: 00000000ffffffff RBX: ffff941534d80e70 RCX: 0000000000024000
[27161.487929] RDX: 0000000000013039 RSI: ffffb087499e3aa5 RDI: ffffb087499e39c7
[27161.489289] RBP: 000000000000000e R08: ffff9414e0f49008 R09: 0000000000001000
[27161.490807] R10: 0000000000000000 R11: 0000000000000003 R12: ffff9414e0f48e70
[27161.492305] R13: ffffb087499e3aa5 R14: 0000000000000000 R15: 0000000000071000
[27161.493845] FS: 00007f8ea58d0b80(0000) GS:ffff94153d400000(0000) knlGS:0000000000000000
[27161.495608] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[27161.496717] CR2: 00007f8ea57a9000 CR3: 0000000016a33000 CR4: 00000000000006f0
[27161.498100] Call Trace:
[27161.498771] __btrfs_drop_extents+0x6ec/0xdf0 [btrfs]
[27161.499872] btrfs_log_changed_extents.isra.26+0x3a2/0x9e0 [btrfs]
[27161.501114] btrfs_log_inode+0x7ff/0xdc0 [btrfs]
[27161.502114] ? __mutex_unlock_slowpath+0x4b/0x2b0
[27161.503172] btrfs_log_inode_parent+0x237/0x9c0 [btrfs]
[27161.504348] btrfs_log_dentry_safe+0x4a/0x70 [btrfs]
[27161.505374] btrfs_sync_file+0x1b7/0x480 [btrfs]
[27161.506371] __x64_sys_msync+0x180/0x210
[27161.507208] do_syscall_64+0x54/0x180
[27161.507932] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[27161.508839] RIP: 0033:0x7f8ea5aa9c61
[27161.512616] RSP: 002b:00007ffea2a06498 EFLAGS: 00000246 ORIG_RAX: 000000000000001a
[27161.514161] RAX: ffffffffffffffda RBX: 000000000002a938 RCX: 00007f8ea5aa9c61
[27161.515376] RDX: 0000000000000004 RSI: 000000000001c9b2 RDI: 00007f8ea578d000
[27161.516572] RBP: 000000000001c07a R08: fffffffffffffff8 R09: 000000000002a000
[27161.517883] R10: 00007f8ea57a99b2 R11: 0000000000000246 R12: 0000000000000938
[27161.519080] R13: 00007f8ea578d000 R14: 000000000001c9b2 R15: 0000000000000000
[27161.520281] Modules linked in: btrfs libcrc32c xor zstd_decompress zstd_compress xxhash raid6_pq loop [last unloaded: scsi_debug]
[27161.522272] ---[ end trace d5afec7ccac6a252 ]---
[27161.523111] RIP: 0010:btrfs_set_item_key_safe+0x146/0x1c0 [btrfs]
[27161.527253] RSP: 0018:ffffb087499e39b0 EFLAGS: 00010286
[27161.528192] RAX: 00000000ffffffff RBX: ffff941534d80e70 RCX: 0000000000024000
[27161.529392] RDX: 0000000000013039 RSI: ffffb087499e3aa5 RDI: ffffb087499e39c7
[27161.530607] RBP: 000000000000000e R08: ffff9414e0f49008 R09: 0000000000001000
[27161.531802] R10: 0000000000000000 R11: 0000000000000003 R12: ffff9414e0f48e70
[27161.533018] R13: ffffb087499e3aa5 R14: 0000000000000000 R15: 0000000000071000
[27161.534405] FS: 00007f8ea58d0b80(0000) GS:ffff94153d400000(0000) knlGS:0000000000000000
[27161.536048] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[27161.537210] CR2: 00007f8ea57a9000 CR3: 0000000016a33000 CR4: 00000000000006f0
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Signed-off-by: David Sterba <dsterba@suse.com>
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Signed-off-by: David Sterba <dsterba@suse.com>
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Signed-off-by: David Sterba <dsterba@suse.com>
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Signed-off-by: David Sterba <dsterba@suse.com>
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Signed-off-by: David Sterba <dsterba@suse.com>
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Signed-off-by: David Sterba <dsterba@suse.com>
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We can read fs_info from extent buffer and can drop it from the
parameters.
Signed-off-by: David Sterba <dsterba@suse.com>
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We can read fs_info from extent buffer and can drop it from the
parameters.
Signed-off-by: David Sterba <dsterba@suse.com>
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We can read fs_info from the transaction and can drop it from the
parameters.
Signed-off-by: David Sterba <dsterba@suse.com>
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We can read fs_info from the transaction and can drop it from the
parameters.
Signed-off-by: David Sterba <dsterba@suse.com>
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We can read fs_info from the transaction and can drop it from the
parameters.
Signed-off-by: David Sterba <dsterba@suse.com>
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We can read fs_info from the transaction and can drop it from the
parameters.
Signed-off-by: David Sterba <dsterba@suse.com>
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We can read fs_info from extent buffer and can drop it from the
parameters.
Signed-off-by: David Sterba <dsterba@suse.com>
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We can read fs_info from extent buffer and can drop it from the
parameters.
Signed-off-by: David Sterba <dsterba@suse.com>
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We can read fs_info from extent buffer and can drop it from the
parameters.
Signed-off-by: David Sterba <dsterba@suse.com>
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We can read fs_info from extent buffer and can drop it from the
parameters.
Signed-off-by: David Sterba <dsterba@suse.com>
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We can read fs_info from extent buffer and can drop it from the
parameters.
Signed-off-by: David Sterba <dsterba@suse.com>
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We can read fs_info from extent buffer and can drop it from the
parameters.
Signed-off-by: David Sterba <dsterba@suse.com>
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BUG_ON(1) leads to bogus warnings from clang when
CONFIG_PROFILE_ANNOTATED_BRANCHES is set:
fs/btrfs/volumes.c:5041:3: error: variable 'max_chunk_size' is used uninitialized whenever 'if' condition is false
[-Werror,-Wsometimes-uninitialized]
BUG_ON(1);
^~~~~~~~~
include/asm-generic/bug.h:61:36: note: expanded from macro 'BUG_ON'
#define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
^~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:48:23: note: expanded from macro 'unlikely'
# define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/btrfs/volumes.c:5046:9: note: uninitialized use occurs here
max_chunk_size);
^~~~~~~~~~~~~~
include/linux/kernel.h:860:36: note: expanded from macro 'min'
#define min(x, y) __careful_cmp(x, y, <)
^
include/linux/kernel.h:853:17: note: expanded from macro '__careful_cmp'
__cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))
^
include/linux/kernel.h:847:25: note: expanded from macro '__cmp_once'
typeof(y) unique_y = (y); \
^
fs/btrfs/volumes.c:5041:3: note: remove the 'if' if its condition is always true
BUG_ON(1);
^
include/asm-generic/bug.h:61:32: note: expanded from macro 'BUG_ON'
#define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
^
fs/btrfs/volumes.c:4993:20: note: initialize the variable 'max_chunk_size' to silence this warning
u64 max_chunk_size;
^
= 0
Change it to BUG() so clang can see that this code path can never
continue.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Sterba <dsterba@suse.com>
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[BUG]
When reading a file from a fuzzed image, kernel can panic like:
BTRFS warning (device loop0): csum failed root 5 ino 270 off 0 csum 0x98f94189 expected csum 0x00000000 mirror 1
assertion failed: !memcmp_extent_buffer(b, &disk_key, offsetof(struct btrfs_leaf, items[0].key), sizeof(disk_key)), file: fs/btrfs/ctree.c, line: 2544
------------[ cut here ]------------
kernel BUG at fs/btrfs/ctree.h:3500!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
RIP: 0010:btrfs_search_slot.cold.24+0x61/0x63 [btrfs]
Call Trace:
btrfs_lookup_csum+0x52/0x150 [btrfs]
__btrfs_lookup_bio_sums+0x209/0x640 [btrfs]
btrfs_submit_bio_hook+0x103/0x170 [btrfs]
submit_one_bio+0x59/0x80 [btrfs]
extent_read_full_page+0x58/0x80 [btrfs]
generic_file_read_iter+0x2f6/0x9d0
__vfs_read+0x14d/0x1a0
vfs_read+0x8d/0x140
ksys_read+0x52/0xc0
do_syscall_64+0x60/0x210
entry_SYSCALL_64_after_hwframe+0x49/0xbe
[CAUSE]
The fuzzed image has a corrupted leaf whose first key doesn't match its
parent:
checksum tree key (CSUM_TREE ROOT_ITEM 0)
node 29741056 level 1 items 14 free 107 generation 19 owner CSUM_TREE
fs uuid 3381d111-94a3-4ac7-8f39-611bbbdab7e6
chunk uuid 9af1c3c7-2af5-488b-8553-530bd515f14c
...
key (EXTENT_CSUM EXTENT_CSUM 79691776) block 29761536 gen 19
leaf 29761536 items 1 free space 1726 generation 19 owner CSUM_TREE
leaf 29761536 flags 0x1(WRITTEN) backref revision 1
fs uuid 3381d111-94a3-4ac7-8f39-611bbbdab7e6
chunk uuid 9af1c3c7-2af5-488b-8553-530bd515f14c
item 0 key (EXTENT_CSUM EXTENT_CSUM 8798638964736) itemoff 1751 itemsize 2244
range start 8798638964736 end 8798641262592 length 2297856
When reading the above tree block, we have extent_buffer->refs = 2 in
the context:
- initial one from __alloc_extent_buffer()
alloc_extent_buffer()
|- __alloc_extent_buffer()
|- atomic_set(&eb->refs, 1)
- one being added to fs_info->buffer_radix
alloc_extent_buffer()
|- check_buffer_tree_ref()
|- atomic_inc(&eb->refs)
So if even we call free_extent_buffer() in read_tree_block or other
similar situation, we only decrease the refs by 1, it doesn't reach 0
and won't be freed right now.
The staled eb and its corrupted content will still be kept cached.
Furthermore, we have several extra cases where we either don't do first
key check or the check is not proper for all callers:
- scrub
We just don't have first key in this context.
- shared tree block
One tree block can be shared by several snapshot/subvolume trees.
In that case, the first key check for one subvolume doesn't apply to
another.
So for the above reasons, a corrupted extent buffer can sneak into the
buffer cache.
[FIX]
Call verify_level_key in read_block_for_search to do another
verification. For that purpose the function is exported.
Due to above reasons, although we can free corrupted extent buffer from
cache, we still need the check in read_block_for_search(), for scrub and
shared tree blocks.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=202755
Link: https://bugzilla.kernel.org/show_bug.cgi?id=202757
Link: https://bugzilla.kernel.org/show_bug.cgi?id=202759
Link: https://bugzilla.kernel.org/show_bug.cgi?id=202761
Link: https://bugzilla.kernel.org/show_bug.cgi?id=202767
Link: https://bugzilla.kernel.org/show_bug.cgi?id=202769
Reported-by: Yoon Jungyeon <jungyeon@gatech.edu>
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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At ctree.c:key_search(), the assertion that verifies the first key on a
child extent buffer corresponds to the key at a specific slot in the
parent has a disadvantage: we effectively hit a BUG_ON() which requires
rebooting the machine later. It also does not tell any information about
which extent buffer is affected, from which root, the expected and found
keys, etc.
However as of commit 581c1760415c48 ("btrfs: Validate child tree block's
level and first key"), that assertion is not needed since at the time we
read an extent buffer from disk we validate that its first key matches the
key, at the respective slot, in the parent extent buffer. Therefore just
remove the assertion at key_search().
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The function map_private_extent_buffer() can return an -EINVAL error, and
it is called by generic_bin_search() which will return back the error. The
btrfs_bin_search() function in turn calls generic_bin_search() and the
key_search() function calls btrfs_bin_search(), so both can return the
-EINVAL error coming from the map_private_extent_buffer() function. Some
callers of these functions were ignoring that these functions can return
an error, so fix them to deal with error return values.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The last caller that does not have a fixed value of lock is
btrfs_set_path_blocking, that actually does the same conditional swtich
by the lock type so we can merge the branches together and remove the
helper.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>
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