Here is output from btrfs check
/ # btrfs check /dev/mmcblk0p1
Warning, could not drop caches
Warning, could not drop caches
Checking filesystem on /dev/mmcblk0p1
UUID: 79af27ae-8fc3-4262-97c0-500d46da169c
checking extents
ref mismatch on [512290816 32768] extent item 6, found 5
Incorrect local backref count on 512290816 root 514 owner 182014 offset 0 found 0 wanted 1 back 0x2296050
Backref disk bytenr does not match extent record, bytenr=512290816, ref bytenr=65536
Backref bytes do not match extent backref, bytenr=512290816, ref bytes=32768, backref bytes=4096
backpointer mismatch on [512290816 32768]
ref mismatch on [512323584 45056] extent item 6, found 5
Incorrect local backref count on 512323584 root 514 owner 182015 offset 0 found 0 wanted 1 back 0x22962e0
Backref disk bytenr does not match extent record, bytenr=512323584, ref bytenr=0
Backref bytes do not match extent backref, bytenr=512323584, ref bytes=45056, backref bytes=4096
backpointer mismatch on [512323584 45056]
ref mismatch on [512368640 40960] extent item 6, found 5
Incorrect local backref count on 512368640 root 514 owner 182017 offset 0 found 0 wanted 1 back 0x2298780
Backref disk bytenr does not match extent record, bytenr=512368640, ref bytenr=742759686981287936
Backref bytes do not match extent backref, bytenr=512368640, ref bytes=40960, backref bytes=4096
backpointer mismatch on [512368640 40960]
ref mismatch on [512610304 32768] extent item 6, found 5
Incorrect local backref count on 512610304 root 514 owner 182019 offset 0 found 0 wanted 1 back 0x2825c90
Backref disk bytenr does not match extent record, bytenr=512610304, ref bytenr=0
Backref bytes do not match extent backref, bytenr=512610304, ref bytes=32768, backref bytes=4096
backpointer mismatch on [512610304 32768]
ref mismatch on [533516288 12288] extent item 6, found 5
Incorrect local backref count on 533516288 root 514 owner 182016 offset 0 found 0 wanted 1 back 0x2e5a4d0
Backref disk bytenr does not match extent record, bytenr=533516288, ref bytenr=0
Backref bytes do not match extent backref, bytenr=533516288, ref bytes=12288, backref bytes=4096
backpointer mismatch on [533516288 12288]
ref mismatch on [533561344 12288] extent item 6, found 5
Incorrect local backref count on 533561344 root 514 owner 182018 offset 0 found 0 wanted 1 back 0x2e5ad10
Backref disk bytenr does not match extent record, bytenr=533561344, ref bytenr=14863849095159611392
Backref bytes do not match extent backref, bytenr=533561344, ref bytes=12288, backref bytes=4096
backpointer mismatch on [533561344 12288]
ref mismatch on [798326784 4096] extent item 2, found 1
Incorrect local backref count on 798326784 root 490 owner 170177 offset 0 found 0 wanted 1 back 0x14ce7a0
Backref disk bytenr does not match extent record, bytenr=798326784, ref bytenr=12826251738751919216
backpointer mismatch on [798326784 4096]
ref mismatch on [798396416 4096] extent item 2, found 1
Incorrect local backref count on 798396416 root 490 owner 170179 offset 0 found 0 wanted 1 back 0x2f49420
Backref disk bytenr does not match extent record, bytenr=798396416, ref bytenr=30786326348292
backpointer mismatch on [798396416 4096]
ref mismatch on [798556160 4096] extent item 2, found 1
Incorrect local backref count on 798556160 root 490 owner 170181 offset 0 found 0 wanted 1 back 0x2f49870
Backref disk bytenr does not match extent record, bytenr=798556160, ref bytenr=0
backpointer mismatch on [798556160 4096]
checking free space cache
checking fs roots
root 514 inode 182018 errors 4000, orphan file extent
The following data extent is lost in tree 514:
inode: 182018, offset:0, disk_bytenr: 533561344, disk_len: 12288
found 1385763627 bytes used err is 1
total csum bytes: 1068884
total tree bytes: 314916864
total fs tree bytes: 291766272
total extent tree bytes: 21000192
btree space waste bytes: 89610909
file data blocks allocated: 5009432576
referenced 4903497728
Warning, could not drop caches