diff mbox series

[v1.1] btrfs-progs: Do metadata prealloc as long as we're not modifying extent tree

Message ID 20180914074944.19526-1-wqu@suse.com (mailing list archive)
State New, archived
Headers show
Series [v1.1] btrfs-progs: Do metadata prealloc as long as we're not modifying extent tree | expand

Commit Message

Qu Wenruo Sept. 14, 2018, 7:49 a.m. UTC 
In github issues, one user reports unexpected ENOSPC error if enabling
datasum.
After some investigation, it looks like that during ext2_saved/image
creation, we could create large file extent whose size can be 128M (max
data extent size).

In that case, its csum will be at least 128K. Under certain case we need
to allocate extra metadata chunks to fulfill such space requirement.

However we only do metadata prealloc if we're reserving extents for fs
trees.
(we use btrfs_root::ref_cows to determine whether we should do metadata
prealloc, and that member is only set for fs trees).

There is no explaination on why we only do metadata prealloc for file
trees, but at least from my investigation, it could be related to avoid
nested extent tree modication.

At least extent reservation for csum tree shouldn't be a problem with
metadata block group preallocation.

So change the metadata block group preallocation check from
"root->ref_cow" to "root->root_key.objectid !=
BTRFS_EXTENT_TREE_OBJECTID", and add some comment for it.

Issue: 123
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
changelog:
v1.1
  Fix stupid subject, from "csum tree" to "extent tree"
---
 extent-tree.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Comments

David Sterba March 5, 2019, 1:55 p.m. UTC | #1 
On Fri, Sep 14, 2018 at 03:49:44PM +0800, Qu Wenruo wrote:
> In github issues, one user reports unexpected ENOSPC error if enabling
> datasum.
> After some investigation, it looks like that during ext2_saved/image
> creation, we could create large file extent whose size can be 128M (max
> data extent size).
> 
> In that case, its csum will be at least 128K. Under certain case we need
> to allocate extra metadata chunks to fulfill such space requirement.
> 
> However we only do metadata prealloc if we're reserving extents for fs
> trees.
> (we use btrfs_root::ref_cows to determine whether we should do metadata
> prealloc, and that member is only set for fs trees).
> 
> There is no explaination on why we only do metadata prealloc for file
> trees, but at least from my investigation, it could be related to avoid
> nested extent tree modication.
> 
> At least extent reservation for csum tree shouldn't be a problem with
> metadata block group preallocation.
> 
> So change the metadata block group preallocation check from
> "root->ref_cow" to "root->root_key.objectid !=
> BTRFS_EXTENT_TREE_OBJECTID", and add some comment for it.

This looks a bit fragile to me but I don't have a better suggestion for
a fix. Added to devel, thanks.
Omar Sandoval March 25, 2019, 6:06 p.m. UTC | #2 
On Tue, Mar 05, 2019 at 02:55:08PM +0100, David Sterba wrote:
> On Fri, Sep 14, 2018 at 03:49:44PM +0800, Qu Wenruo wrote:
> > In github issues, one user reports unexpected ENOSPC error if enabling
> > datasum.
> > After some investigation, it looks like that during ext2_saved/image
> > creation, we could create large file extent whose size can be 128M (max
> > data extent size).
> > 
> > In that case, its csum will be at least 128K. Under certain case we need
> > to allocate extra metadata chunks to fulfill such space requirement.
> > 
> > However we only do metadata prealloc if we're reserving extents for fs
> > trees.
> > (we use btrfs_root::ref_cows to determine whether we should do metadata
> > prealloc, and that member is only set for fs trees).
> > 
> > There is no explaination on why we only do metadata prealloc for file
> > trees, but at least from my investigation, it could be related to avoid
> > nested extent tree modication.
> > 
> > At least extent reservation for csum tree shouldn't be a problem with
> > metadata block group preallocation.
> > 
> > So change the metadata block group preallocation check from
> > "root->ref_cow" to "root->root_key.objectid !=
> > BTRFS_EXTENT_TREE_OBJECTID", and add some comment for it.
> 
> This looks a bit fragile to me but I don't have a better suggestion for
> a fix. Added to devel, thanks.

This seems to be causing infinite recursion in do_chunk_alloc() during mkfs:

$ truncate -s $((1024 * 1024 * 1024)) foo
$ gdb --args ./mkfs.btrfs foo
GNU gdb (GDB) 8.2.1
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "x86_64-pc-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
    <http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from ./mkfs.btrfs...done.
(gdb) r
Starting program: /home/osandov/linux/btrfs-progs/mkfs.btrfs foo
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/libthread_db.so.1".
btrfs-progs v4.20.2
See http://btrfs.wiki.kernel.org for more information.


Program received signal SIGSEGV, Segmentation fault.
0x000055555557fe24 in memcpy (__len=17, __src=0x5555555e5ef5, __dest=0x7fffff7ff040) at /usr/include/bits/string_fortified.h:34
34        return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest));
(gdb) bt
#0  0x000055555557fe24 in memcpy (__len=17, __src=0x5555555e5ef5, __dest=0x7fffff7ff040) at /usr/include/bits/string_fortified.h:34
#1  read_extent_buffer (eb=eb@entry=0x5555555e5e10, dst=dst@entry=0x7fffff7ff040, start=start@entry=101, len=len@entry=17) at extent_io.c:975
#2  0x0000555555565d1e in btrfs_item_key (nr=0, disk_key=0x7fffff7ff040, eb=0x5555555e5e10) at ctree.h:1905
#3  __btrfs_cow_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, buf=buf@entry=0x5555555e5e10, parent=parent@entry=0x0, parent_slot=parent_slot@entry=0, cow_ret=cow_ret@entry=0x7fffff7ff288, search_start=0, empty_size=0) at ctree.c:291
#4  0x0000555555566676 in btrfs_cow_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, buf=0x5555555e5e10, parent=0x0, parent_slot=0, cow_ret=cow_ret@entry=0x7fffff7ff288) at ctree.c:388
#5  0x0000555555569319 in btrfs_search_slot (trans=<optimized out>, root=root@entry=0x5555555d3e40, key=key@entry=0x7fffff7ff440, p=p@entry=0x555555738ea0, ins_len=ins_len@entry=73, cow=cow@entry=1) at ctree.c:1158
#6  0x000055555556ab6f in btrfs_insert_empty_items (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, path=path@entry=0x555555738ea0, cpu_key=cpu_key@entry=0x7fffff7ff440, data_size=data_size@entry=0x7fffff7ff43c, nr=nr@entry=1) at ctree.c:2612
#7  0x0000555555580ad7 in btrfs_insert_empty_item (data_size=<optimized out>, key=0x7fffff7ff440, path=0x555555738ea0, root=0x5555555d3e40, trans=0x5555555f2430) at ctree.h:2650
#8  btrfs_insert_dev_extent (trans=trans@entry=0x5555555f2430, device=device@entry=0x5555555d59e0, chunk_offset=chunk_offset@entry=5242880, num_bytes=num_bytes@entry=8388608, start=5242880) at volumes.c:574
#9  0x00005555555818c1 in btrfs_alloc_dev_extent (start=0x7fffff7ff568, num_bytes=8388608, chunk_offset=5242880, device=0x5555555d59e0, trans=0x5555555f2430) at volumes.c:610
#10 btrfs_alloc_chunk (trans=trans@entry=0x5555555f2430, info=info@entry=0x5555555d2970, start=start@entry=0x7fffff7ff698, num_bytes=num_bytes@entry=0x7fffff7ff6a0, type=4) at volumes.c:1143
#11 0x0000555555575ca4 in do_chunk_alloc (trans=trans@entry=0x5555555f2430, fs_info=fs_info@entry=0x5555555d2970, alloc_bytes=alloc_bytes@entry=16384, flags=flags@entry=4) at extent-tree.c:1876
#12 0x0000555555575f8d in btrfs_reserve_extent (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, num_bytes=num_bytes@entry=16384, empty_size=empty_size@entry=0, hint_byte=hint_byte@entry=0, search_end=search_end@entry=18446744073709551615, ins=0x7fffff7ff8c0, is_data=false) at extent-tree.c:2516
#13 0x0000555555576914 in alloc_tree_block (ins=0x7fffff7ff8c0, search_end=18446744073709551615, hint_byte=0, empty_size=0, level=0, key=0x7fffff7ff960, flags=0, generation=<optimized out>, root_objectid=4, num_bytes=16384, root=0x5555555d3e40, trans=0x5555555f2430) at extent-tree.c:2641
#14 btrfs_alloc_free_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, blocksize=16384, root_objectid=4, key=key@entry=0x7fffff7ff960, level=level@entry=0, hint=0, empty_size=0) at extent-tree.c:2694
#15 0x0000555555565d4a in __btrfs_cow_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, buf=buf@entry=0x5555555e5e10, parent=parent@entry=0x0, parent_slot=parent_slot@entry=0, cow_ret=cow_ret@entry=0x7fffff7ffba8, search_start=0, empty_size=0) at ctree.c:295
#16 0x0000555555566676 in btrfs_cow_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, buf=0x5555555e5e10, parent=0x0, parent_slot=0, cow_ret=cow_ret@entry=0x7fffff7ffba8) at ctree.c:388
#17 0x0000555555569319 in btrfs_search_slot (trans=<optimized out>, root=root@entry=0x5555555d3e40, key=key@entry=0x7fffff7ffd60, p=p@entry=0x555555738d30, ins_len=ins_len@entry=73, cow=cow@entry=1) at ctree.c:1158
#18 0x000055555556ab6f in btrfs_insert_empty_items (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, path=path@entry=0x555555738d30, cpu_key=cpu_key@entry=0x7fffff7ffd60, data_size=data_size@entry=0x7fffff7ffd5c, nr=nr@entry=1) at ctree.c:2612
#19 0x0000555555580ad7 in btrfs_insert_empty_item (data_size=<optimized out>, key=0x7fffff7ffd60, path=0x555555738d30, root=0x5555555d3e40, trans=0x5555555f2430) at ctree.h:2650
#20 btrfs_insert_dev_extent (trans=trans@entry=0x5555555f2430, device=device@entry=0x5555555d59e0, chunk_offset=chunk_offset@entry=5242880, num_bytes=num_bytes@entry=8388608, start=5242880) at volumes.c:574
#21 0x00005555555818c1 in btrfs_alloc_dev_extent (start=0x7fffff7ffe88, num_bytes=8388608, chunk_offset=5242880, device=0x5555555d59e0, trans=0x5555555f2430) at volumes.c:610
#22 btrfs_alloc_chunk (trans=trans@entry=0x5555555f2430, info=info@entry=0x5555555d2970, start=start@entry=0x7fffff7fffb8, num_bytes=num_bytes@entry=0x7fffff7fffc0, type=4) at volumes.c:1143
#23 0x0000555555575ca4 in do_chunk_alloc (trans=trans@entry=0x5555555f2430, fs_info=fs_info@entry=0x5555555d2970, alloc_bytes=alloc_bytes@entry=16384, flags=flags@entry=4) at extent-tree.c:1876
#24 0x0000555555575f8d in btrfs_reserve_extent (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, num_bytes=num_bytes@entry=16384, empty_size=empty_size@entry=0, hint_byte=hint_byte@entry=0, search_end=search_end@entry=18446744073709551615, ins=0x7fffff8001e0, is_data=false) at extent-tree.c:2516
#25 0x0000555555576914 in alloc_tree_block (ins=0x7fffff8001e0, search_end=18446744073709551615, hint_byte=0, empty_size=0, level=0, key=0x7fffff800280, flags=0, generation=<optimized out>, root_objectid=4, num_bytes=16384, root=0x5555555d3e40, trans=0x5555555f2430) at extent-tree.c:2641
#26 btrfs_alloc_free_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, blocksize=16384, root_objectid=4, key=key@entry=0x7fffff800280, level=level@entry=0, hint=0, empty_size=0) at extent-tree.c:2694
#27 0x0000555555565d4a in __btrfs_cow_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, buf=buf@entry=0x5555555e5e10, parent=parent@entry=0x0, parent_slot=parent_slot@entry=0, cow_ret=cow_ret@entry=0x7fffff8004c8, search_start=0, empty_size=0) at ctree.c:295
#28 0x0000555555566676 in btrfs_cow_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, buf=0x5555555e5e10, parent=0x0, parent_slot=0, cow_ret=cow_ret@entry=0x7fffff8004c8) at ctree.c:388
#29 0x0000555555569319 in btrfs_search_slot (trans=<optimized out>, root=root@entry=0x5555555d3e40, key=key@entry=0x7fffff800680, p=p@entry=0x555555738bc0, ins_len=ins_len@entry=73, cow=cow@entry=1) at ctree.c:1158
#30 0x000055555556ab6f in btrfs_insert_empty_items (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, path=path@entry=0x555555738bc0, cpu_key=cpu_key@entry=0x7fffff800680, data_size=data_size@entry=0x7fffff80067c, nr=nr@entry=1) at ctree.c:2612
#31 0x0000555555580ad7 in btrfs_insert_empty_item (data_size=<optimized out>, key=0x7fffff800680, path=0x555555738bc0, root=0x5555555d3e40, trans=0x5555555f2430) at ctree.h:2650
#32 btrfs_insert_dev_extent (trans=trans@entry=0x5555555f2430, device=device@entry=0x5555555d59e0, chunk_offset=chunk_offset@entry=5242880, num_bytes=num_bytes@entry=8388608, start=5242880) at volumes.c:574
#33 0x00005555555818c1 in btrfs_alloc_dev_extent (start=0x7fffff8007a8, num_bytes=8388608, chunk_offset=5242880, device=0x5555555d59e0, trans=0x5555555f2430) at volumes.c:610
#34 btrfs_alloc_chunk (trans=trans@entry=0x5555555f2430, info=info@entry=0x5555555d2970, start=start@entry=0x7fffff8008d8, num_bytes=num_bytes@entry=0x7fffff8008e0, type=4) at volumes.c:1143
#35 0x0000555555575ca4 in do_chunk_alloc (trans=trans@entry=0x5555555f2430, fs_info=fs_info@entry=0x5555555d2970, alloc_bytes=alloc_bytes@entry=16384, flags=flags@entry=4) at extent-tree.c:1876
Qu Wenruo March 25, 2019, 11:05 p.m. UTC | #3 
On 2019/3/26 上午2:06, Omar Sandoval wrote:
> On Tue, Mar 05, 2019 at 02:55:08PM +0100, David Sterba wrote:
>> On Fri, Sep 14, 2018 at 03:49:44PM +0800, Qu Wenruo wrote:
>>> In github issues, one user reports unexpected ENOSPC error if enabling
>>> datasum.
>>> After some investigation, it looks like that during ext2_saved/image
>>> creation, we could create large file extent whose size can be 128M (max
>>> data extent size).
>>>
>>> In that case, its csum will be at least 128K. Under certain case we need
>>> to allocate extra metadata chunks to fulfill such space requirement.
>>>
>>> However we only do metadata prealloc if we're reserving extents for fs
>>> trees.
>>> (we use btrfs_root::ref_cows to determine whether we should do metadata
>>> prealloc, and that member is only set for fs trees).
>>>
>>> There is no explaination on why we only do metadata prealloc for file
>>> trees, but at least from my investigation, it could be related to avoid
>>> nested extent tree modication.
>>>
>>> At least extent reservation for csum tree shouldn't be a problem with
>>> metadata block group preallocation.
>>>
>>> So change the metadata block group preallocation check from
>>> "root->ref_cow" to "root->root_key.objectid !=
>>> BTRFS_EXTENT_TREE_OBJECTID", and add some comment for it.
>>
>> This looks a bit fragile to me but I don't have a better suggestion for
>> a fix. Added to devel, thanks.
> 
> This seems to be causing infinite recursion in do_chunk_alloc() during mkfs:

I can also reproduce it.

And indeed it's caused by this patch.

Please discard this patch until a better solution is found.

Thanks,
Qu
> 
> $ truncate -s $((1024 * 1024 * 1024)) foo
> $ gdb --args ./mkfs.btrfs foo
> GNU gdb (GDB) 8.2.1
> Copyright (C) 2018 Free Software Foundation, Inc.
> License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
> This is free software: you are free to change and redistribute it.
> There is NO WARRANTY, to the extent permitted by law.
> Type "show copying" and "show warranty" for details.
> This GDB was configured as "x86_64-pc-linux-gnu".
> Type "show configuration" for configuration details.
> For bug reporting instructions, please see:
> <http://www.gnu.org/software/gdb/bugs/>.
> Find the GDB manual and other documentation resources online at:
>     <http://www.gnu.org/software/gdb/documentation/>.
> 
> For help, type "help".
> Type "apropos word" to search for commands related to "word"...
> Reading symbols from ./mkfs.btrfs...done.
> (gdb) r
> Starting program: /home/osandov/linux/btrfs-progs/mkfs.btrfs foo
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/usr/lib/libthread_db.so.1".
> btrfs-progs v4.20.2
> See http://btrfs.wiki.kernel.org for more information.
> 
> 
> Program received signal SIGSEGV, Segmentation fault.
> 0x000055555557fe24 in memcpy (__len=17, __src=0x5555555e5ef5, __dest=0x7fffff7ff040) at /usr/include/bits/string_fortified.h:34
> 34        return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest));
> (gdb) bt
> #0  0x000055555557fe24 in memcpy (__len=17, __src=0x5555555e5ef5, __dest=0x7fffff7ff040) at /usr/include/bits/string_fortified.h:34
> #1  read_extent_buffer (eb=eb@entry=0x5555555e5e10, dst=dst@entry=0x7fffff7ff040, start=start@entry=101, len=len@entry=17) at extent_io.c:975
> #2  0x0000555555565d1e in btrfs_item_key (nr=0, disk_key=0x7fffff7ff040, eb=0x5555555e5e10) at ctree.h:1905
> #3  __btrfs_cow_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, buf=buf@entry=0x5555555e5e10, parent=parent@entry=0x0, parent_slot=parent_slot@entry=0, cow_ret=cow_ret@entry=0x7fffff7ff288, search_start=0, empty_size=0) at ctree.c:291
> #4  0x0000555555566676 in btrfs_cow_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, buf=0x5555555e5e10, parent=0x0, parent_slot=0, cow_ret=cow_ret@entry=0x7fffff7ff288) at ctree.c:388
> #5  0x0000555555569319 in btrfs_search_slot (trans=<optimized out>, root=root@entry=0x5555555d3e40, key=key@entry=0x7fffff7ff440, p=p@entry=0x555555738ea0, ins_len=ins_len@entry=73, cow=cow@entry=1) at ctree.c:1158
> #6  0x000055555556ab6f in btrfs_insert_empty_items (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, path=path@entry=0x555555738ea0, cpu_key=cpu_key@entry=0x7fffff7ff440, data_size=data_size@entry=0x7fffff7ff43c, nr=nr@entry=1) at ctree.c:2612
> #7  0x0000555555580ad7 in btrfs_insert_empty_item (data_size=<optimized out>, key=0x7fffff7ff440, path=0x555555738ea0, root=0x5555555d3e40, trans=0x5555555f2430) at ctree.h:2650
> #8  btrfs_insert_dev_extent (trans=trans@entry=0x5555555f2430, device=device@entry=0x5555555d59e0, chunk_offset=chunk_offset@entry=5242880, num_bytes=num_bytes@entry=8388608, start=5242880) at volumes.c:574
> #9  0x00005555555818c1 in btrfs_alloc_dev_extent (start=0x7fffff7ff568, num_bytes=8388608, chunk_offset=5242880, device=0x5555555d59e0, trans=0x5555555f2430) at volumes.c:610
> #10 btrfs_alloc_chunk (trans=trans@entry=0x5555555f2430, info=info@entry=0x5555555d2970, start=start@entry=0x7fffff7ff698, num_bytes=num_bytes@entry=0x7fffff7ff6a0, type=4) at volumes.c:1143
> #11 0x0000555555575ca4 in do_chunk_alloc (trans=trans@entry=0x5555555f2430, fs_info=fs_info@entry=0x5555555d2970, alloc_bytes=alloc_bytes@entry=16384, flags=flags@entry=4) at extent-tree.c:1876
> #12 0x0000555555575f8d in btrfs_reserve_extent (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, num_bytes=num_bytes@entry=16384, empty_size=empty_size@entry=0, hint_byte=hint_byte@entry=0, search_end=search_end@entry=18446744073709551615, ins=0x7fffff7ff8c0, is_data=false) at extent-tree.c:2516
> #13 0x0000555555576914 in alloc_tree_block (ins=0x7fffff7ff8c0, search_end=18446744073709551615, hint_byte=0, empty_size=0, level=0, key=0x7fffff7ff960, flags=0, generation=<optimized out>, root_objectid=4, num_bytes=16384, root=0x5555555d3e40, trans=0x5555555f2430) at extent-tree.c:2641
> #14 btrfs_alloc_free_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, blocksize=16384, root_objectid=4, key=key@entry=0x7fffff7ff960, level=level@entry=0, hint=0, empty_size=0) at extent-tree.c:2694
> #15 0x0000555555565d4a in __btrfs_cow_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, buf=buf@entry=0x5555555e5e10, parent=parent@entry=0x0, parent_slot=parent_slot@entry=0, cow_ret=cow_ret@entry=0x7fffff7ffba8, search_start=0, empty_size=0) at ctree.c:295
> #16 0x0000555555566676 in btrfs_cow_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, buf=0x5555555e5e10, parent=0x0, parent_slot=0, cow_ret=cow_ret@entry=0x7fffff7ffba8) at ctree.c:388
> #17 0x0000555555569319 in btrfs_search_slot (trans=<optimized out>, root=root@entry=0x5555555d3e40, key=key@entry=0x7fffff7ffd60, p=p@entry=0x555555738d30, ins_len=ins_len@entry=73, cow=cow@entry=1) at ctree.c:1158
> #18 0x000055555556ab6f in btrfs_insert_empty_items (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, path=path@entry=0x555555738d30, cpu_key=cpu_key@entry=0x7fffff7ffd60, data_size=data_size@entry=0x7fffff7ffd5c, nr=nr@entry=1) at ctree.c:2612
> #19 0x0000555555580ad7 in btrfs_insert_empty_item (data_size=<optimized out>, key=0x7fffff7ffd60, path=0x555555738d30, root=0x5555555d3e40, trans=0x5555555f2430) at ctree.h:2650
> #20 btrfs_insert_dev_extent (trans=trans@entry=0x5555555f2430, device=device@entry=0x5555555d59e0, chunk_offset=chunk_offset@entry=5242880, num_bytes=num_bytes@entry=8388608, start=5242880) at volumes.c:574
> #21 0x00005555555818c1 in btrfs_alloc_dev_extent (start=0x7fffff7ffe88, num_bytes=8388608, chunk_offset=5242880, device=0x5555555d59e0, trans=0x5555555f2430) at volumes.c:610
> #22 btrfs_alloc_chunk (trans=trans@entry=0x5555555f2430, info=info@entry=0x5555555d2970, start=start@entry=0x7fffff7fffb8, num_bytes=num_bytes@entry=0x7fffff7fffc0, type=4) at volumes.c:1143
> #23 0x0000555555575ca4 in do_chunk_alloc (trans=trans@entry=0x5555555f2430, fs_info=fs_info@entry=0x5555555d2970, alloc_bytes=alloc_bytes@entry=16384, flags=flags@entry=4) at extent-tree.c:1876
> #24 0x0000555555575f8d in btrfs_reserve_extent (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, num_bytes=num_bytes@entry=16384, empty_size=empty_size@entry=0, hint_byte=hint_byte@entry=0, search_end=search_end@entry=18446744073709551615, ins=0x7fffff8001e0, is_data=false) at extent-tree.c:2516
> #25 0x0000555555576914 in alloc_tree_block (ins=0x7fffff8001e0, search_end=18446744073709551615, hint_byte=0, empty_size=0, level=0, key=0x7fffff800280, flags=0, generation=<optimized out>, root_objectid=4, num_bytes=16384, root=0x5555555d3e40, trans=0x5555555f2430) at extent-tree.c:2641
> #26 btrfs_alloc_free_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, blocksize=16384, root_objectid=4, key=key@entry=0x7fffff800280, level=level@entry=0, hint=0, empty_size=0) at extent-tree.c:2694
> #27 0x0000555555565d4a in __btrfs_cow_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, buf=buf@entry=0x5555555e5e10, parent=parent@entry=0x0, parent_slot=parent_slot@entry=0, cow_ret=cow_ret@entry=0x7fffff8004c8, search_start=0, empty_size=0) at ctree.c:295
> #28 0x0000555555566676 in btrfs_cow_block (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, buf=0x5555555e5e10, parent=0x0, parent_slot=0, cow_ret=cow_ret@entry=0x7fffff8004c8) at ctree.c:388
> #29 0x0000555555569319 in btrfs_search_slot (trans=<optimized out>, root=root@entry=0x5555555d3e40, key=key@entry=0x7fffff800680, p=p@entry=0x555555738bc0, ins_len=ins_len@entry=73, cow=cow@entry=1) at ctree.c:1158
> #30 0x000055555556ab6f in btrfs_insert_empty_items (trans=trans@entry=0x5555555f2430, root=root@entry=0x5555555d3e40, path=path@entry=0x555555738bc0, cpu_key=cpu_key@entry=0x7fffff800680, data_size=data_size@entry=0x7fffff80067c, nr=nr@entry=1) at ctree.c:2612
> #31 0x0000555555580ad7 in btrfs_insert_empty_item (data_size=<optimized out>, key=0x7fffff800680, path=0x555555738bc0, root=0x5555555d3e40, trans=0x5555555f2430) at ctree.h:2650
> #32 btrfs_insert_dev_extent (trans=trans@entry=0x5555555f2430, device=device@entry=0x5555555d59e0, chunk_offset=chunk_offset@entry=5242880, num_bytes=num_bytes@entry=8388608, start=5242880) at volumes.c:574
> #33 0x00005555555818c1 in btrfs_alloc_dev_extent (start=0x7fffff8007a8, num_bytes=8388608, chunk_offset=5242880, device=0x5555555d59e0, trans=0x5555555f2430) at volumes.c:610
> #34 btrfs_alloc_chunk (trans=trans@entry=0x5555555f2430, info=info@entry=0x5555555d2970, start=start@entry=0x7fffff8008d8, num_bytes=num_bytes@entry=0x7fffff8008e0, type=4) at volumes.c:1143
> #35 0x0000555555575ca4 in do_chunk_alloc (trans=trans@entry=0x5555555f2430, fs_info=fs_info@entry=0x5555555d2970, alloc_bytes=alloc_bytes@entry=16384, flags=flags@entry=4) at extent-tree.c:1876
>
diff mbox series

Patch

diff --git a/extent-tree.c b/extent-tree.c
index 5d49af5a901e..bdf1b0e94c5f 100644
--- a/extent-tree.c
+++ b/extent-tree.c
@@ -2652,7 +2652,12 @@  int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
 		profile = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
 	}
 
-	if (root->ref_cows) {
+	/*
+	 * Do metadata preallocate if we're not modifying extent tree.
+	 * Allocating chunk while modify extent tree could lead to tranid
+	 * mismatch, as do_chunk_alloc() could commit transaction.
+	 */
+	if (root->root_key.objectid != BTRFS_EXTENT_TREE_OBJECTID) {
 		if (!(profile & BTRFS_BLOCK_GROUP_METADATA)) {
 			ret = do_chunk_alloc(trans, info,
 					     num_bytes,