我们正在使用 BTRFS 文件系统，信息如下df -h：
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_brick4-lv_brick4 22T 7.3T 15T 34% /NFS/SHARE
有大量可用空间，但我们仍然遇到错误，导致NFS其他机器上的共享exports在一段时间内以只读方式共享此挂载。发生时有一个日志，来自/var/log/messages
这个错误说了什么？感谢您的帮助。
Aug 28 10:55:15 gfs4 kernel: ------------[ cut here ]------------
Aug 28 10:55:15 gfs4 kernel: BTRFS: error (device dm-3) in __btrfs_free_extent:5990: errno=-28 No space left
Aug 28 10:55:15 gfs4 kernel: BTRFS info (device dm-3): forced readonly
Aug 28 10:55:15 gfs4 kernel: BTRFS: error (device dm-3) in btrfs_run_delayed_refs:2792: errno=-28 No space left
Aug 28 10:55:15 gfs4 kernel: WARNING: at fs/btrfs/super.c:260 __btrfs_abort_transaction+0xed/0x140 [btrfs]()
Aug 28 10:55:15 gfs4 kernel: Modules linked in: nfsv3 nfs fscache binfmt_misc btrfs zlib_deflate raid6_pq xor iTCO_wdt iTCO_vendor_support ppdev ipmi_ssif coretemp kvm pcspkr i2c_i801 lpc_ich mfd_core ses enclosure sg ipmi_si parport_pc ipmi_msghandler parport tpm_infineon i7core_edac ioatdma edac_core shpchp acpi_cpufreq nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c sd_mod crc_t10dif crct10dif_generic crct10dif_common ast syscopyarea sysfillrect sysimgblt ahci drm_kms_helper libahci crc32c_intel ttm serio_raw libata drm e1000e aacraid ixgbe(OE) igb vxlan ip6_udp_tunnel udp_tunnel dca ptp i2c_algo_bit pps_core i2c_core dm_mirror dm_region_hash dm_log dm_mod
Aug 28 10:55:15 gfs4 kernel: CPU: 2 PID: 820 Comm: btrfs-transacti Tainted: G OE ------------ 3.10.0-327.28.2.el7.x86_64 #1
Aug 28 10:55:15 gfs4 kernel: Hardware name: empty empty/S7012, BIOS 'V3.01 ' 09/23/2011
Aug 28 10:55:15 gfs4 kernel: ffff880810a3fad8 00000000e953665d ffff880810a3fa90 ffffffff81636553
Aug 28 10:55:15 gfs4 kernel: ffff880810a3fac8 ffffffff8107b200 ffff880484bc5e40 ffff88081160e000
Aug 28 10:55:15 gfs4 kernel: 00000000ffffffe4 ffffffffa06b6f70 0000000000001766 ffff880810a3fb30
Aug 28 10:55:15 gfs4 kernel: Call Trace:
Aug 28 10:55:15 gfs4 kernel: [<ffffffff81636553>] dump_stack+0x19/0x1b
Aug 28 10:55:15 gfs4 kernel: [<ffffffff8107b200>] warn_slowpath_common+0x70/0xb0
Aug 28 10:55:15 gfs4 kernel: [<ffffffff8107b29c>] warn_slowpath_fmt+0x5c/0x80
Aug 28 10:55:15 gfs4 kernel: [<ffffffffa0619bf7>] ? update_block_group.isra.60+0xd7/0x2f0 [btrfs]
Aug 28 10:55:15 gfs4 kernel: [<ffffffffa0606f6d>] __btrfs_abort_transaction+0xed/0x140 [btrfs]
Aug 28 10:55:15 gfs4 kernel: [<ffffffffa061a11d>] __btrfs_free_extent+0x30d/0xbf0 [btrfs]
Aug 28 10:55:15 gfs4 kernel: [<ffffffffa061f760>] __btrfs_run_delayed_refs+0x430/0x1220 [btrfs]
Aug 28 10:55:15 gfs4 kernel: [<ffffffffa0624693>] btrfs_run_delayed_refs.part.65+0x73/0x270 [btrfs]
Aug 28 10:55:15 gfs4 kernel: [<ffffffffa06248a7>] btrfs_run_delayed_refs+0x17/0x20 [btrfs]
Aug 28 10:55:15 gfs4 kernel: [<ffffffffa0635d06>] btrfs_commit_transaction+0x56/0xa50 [btrfs]
Aug 28 10:55:15 gfs4 kernel: [<ffffffffa06317c5>] transaction_kthread+0x1b5/0x240 [btrfs]
Aug 28 10:55:15 gfs4 kernel: [<ffffffffa0631610>] ? btrfs_cleanup_transaction+0x560/0x560 [btrfs]
Aug 28 10:55:15 gfs4 kernel: [<ffffffff810a5b2f>] kthread+0xcf/0xe0
Aug 28 10:55:15 gfs4 kernel: [<ffffffff810a5a60>] ? kthread_create_on_node+0x140/0x140
Aug 28 10:55:15 gfs4 kernel: [<ffffffff81646b98>] ret_from_fork+0x58/0x90
Aug 28 10:55:15 gfs4 kernel: [<ffffffff810a5a60>] ? kthread_create_on_node+0x140/0x140
Aug 28 10:55:15 gfs4 kernel: ---[ end trace 9a2a2f9b37b65581 ]---
Aug 28 10:55:15 gfs4 kernel: BTRFS: error (device dm-3) in __btrfs_free_extent:5990: errno=-28 No space left
Aug 28 10:55:15 gfs4 kernel: BTRFS: error (device dm-3) in btrfs_run_delayed_refs:2792: errno=-28 No space left
答案1
有一个有关此主题的 btrfs 常见问题解答，请参阅此链接。。 也可以看看超级用户上的这个答案。