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 >
signature.asc
Description: OpenPGP digital signature
