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
