On OpenWrt on a Turris Omnia, I set up a share on a btrfs liek this: [Time Machine Mary] path = /srv/shares/timemachine/mary create mask = 0666 directory mask = 0777 read only = no guest ok = no fruit:encoding = native fruit:metadata = stream fruit:veto_appledouble = no fruit:time machine = yes fruit:time machine max size = 350G vfs objects = catia fruit streams_xattr The first backup (macOS 11.6) ran fine, but after that mounting the share fails with a very generic error message on the mac, and on the router, I'm getting these: 14 17:17:58.894957, 0] ../../source3/modules/vfs_fruit.c:6982(fruit_tmsize_do_dirent) Sep 14 21:17:58 emerson smbd[16361]: fruit_tmsize_do_dirent: tmsize potential overflow: bandsize [33554432] nbands [1931] Sep 14 21:17:58 emerson smbd[16361]: [2021/09/14 17:17:58.895241, 0] ../../source3/smbd/dfree.c:136(sys_disk_free) Sep 14 21:17:58 emerson smbd[16361]: sys_disk_free: VFS disk_free failed. Error was : No error information This is a ARMv7 processer: processor : 0 model name : ARMv7 Processor rev 1 (v7l) BogoMIPS : 1600.00 Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpd32 CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x4 CPU part : 0xc09 CPU revision : 1 processor : 1 model name : ARMv7 Processor rev 1 (v7l) BogoMIPS : 1600.00 Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpd32 CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x4 CPU part : 0xc09 CPU revision : 1 Hardware : Marvell Armada 380/385 (Device Tree) Revision : 0000 Serial : 0000000E00001FB5 Samba is from the standard OpenWrt package repository, specifically these: smbd 4.11.17, from the opkg packages: samba4-admin - 4.11.17-3.7-2 samba4-client - 4.11.17-3.7-2 samba4-libs - 4.11.17-3.7-2 samba4-server - 4.11.17-3.7-2 samba4-utils - 4.11.17-3.7-2 This sounds like it is the same or similar to 13622. It also could be related to 14409.
In my TM backups, I am seeing only *.sparsebundle entries, so the report in 14409 does not seem to apply to my case.
OpenWrt forum thread: https://forum.openwrt.org/t/samba4-time-machine-unable-to-mount-share/106696/6
Here's a debug log, I hope I captured the relevant portion: push_sec_ctx(1000, 1000) : sec_ctx_stack_ndx = 1 push_conn_ctx(3636292611) : conn_ctx_stack_ndx = 0 setting sec ctx (0, 0) - sec_ctx_stack_ndx = 1 Security token: (NULL) UNIX token of user 0 Primary group is 0 and contains 0 supplementary groups pop_sec_ctx (1000, 1000) - sec_ctx_stack_ndx = 0 change_to_user_impersonate: Skipping user change - already user print_impersonation_info: Impersonated user: uid=(1000,1000), gid=(0,1000), cwd=[/srv/shares/timemachine/mary] smbd_do_qfsinfo: level = 1003 allocated file structure fnum [invalid value] (2 used) unix_mode: unix_mode(/srv/shares/timemachine/mary/Mary MacBook.sparsebundle/Info.plist) returning 0666 dos_mode_debug_print: parse_dos_attribute_blob returning (0x20): "a" calling open_file with flags=0x0 flags2=0x0 mode=0666, access_mask = 0x120089, open_access_mask = 0x120089 push_sec_ctx(1000, 1000) : sec_ctx_stack_ndx = 1 push_conn_ctx(3636292611) : conn_ctx_stack_ndx = 0 setting sec ctx (0, 0) - sec_ctx_stack_ndx = 1 Security token: (NULL) UNIX token of user 0 Primary group is 0 and contains 0 supplementary groups pop_sec_ctx (1000, 1000) - sec_ctx_stack_ndx = 0 vfs_ChDir to /srv/shares/timemachine/mary/Mary MacBook.sparsebundle vfs_ChDir got /srv/shares/timemachine/mary/Mary MacBook.sparsebundle check_reduced_name: Info.plist reduced to /srv/shares/timemachine/mary/Mary MacBook.sparsebundle/Info.plist vfs_ChDir to /srv/shares/timemachine/mary vfs_ChDir got /srv/shares/timemachine/mary mary opened file /srv/shares/timemachine/mary/Mary MacBook.sparsebundle/Info.plist read=Yes write=No (numopen=2) dbwrap_lock_order_lock: check lock order 1 for /var/lock/locking.tdb set_file_oplock: granted oplock on file /srv/shares/timemachine/mary/Mary MacBook.sparsebundle/Info.plist, 32:105:0/0, tv_sec = 61474dc9, tv_usec = d517b dbwrap_lock_order_unlock: release lock order 1 for /var/lock/locking.tdb dbwrap_lock_order_lock: check lock order 1 for /var/lock/locking.tdb dbwrap_lock_order_unlock: release lock order 1 for /var/lock/locking.tdb mary closed file /srv/shares/timemachine/mary/Mary MacBook.sparsebundle/Info.plist (numopen=1) NT_STATUS_OK freed files structure 0 (1 used) fruit_tmsize_do_dirent: tmsize potential overflow: bandsize [33554432] nbands [2127] sys_disk_free: VFS disk_free failed. Error was : No error information smbd_smb2_request_error_ex: smbd_smb2_request_error_ex: idx[5] status[NT_STATUS_UNSUCCESSFUL] || at ../../source3/smbd/smb2_getinfo.c:159 change_to_user_impersonate: Skipping user change - already user print_impersonation_info: Impersonated user: uid=(1000,1000), gid=(0,1000), cwd=[/srv/shares/timemachine/mary] dbwrap_lock_order_lock: check lock order 1 for /var/lock/locking.tdb dbwrap_lock_order_unlock: release lock order 1 for /var/lock/locking.tdb dbwrap_lock_order_lock: check lock order 1 for /var/lock/smbXsrv_open_global.tdb dbwrap_lock_order_unlock: release lock order 1 for /var/lock/smbXsrv_open_global.tdb freed files structure 405190144 (0 used)