On Tue, 4 Mar 2014 10:19:20 -0500, Josef Bacik wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On 01/15/2014 07:00 AM, Miao Xie wrote: >> When we mounted the filesystem after the crash, we got the >> following message: BTRFS error (device xxx): block group 4315938816 >> has wrong amount of free space BTRFS error (device xxx): failed to >> load free space cache for block group 4315938816 >> >> It is because we didn't update the metadata of the allocated space >> until the file data was written into the disk. During this time, >> there was no information about the allocated spaces in either the >> extent tree nor the free space cache. when we wrote out the free >> space cache at this time, those spaces were lost. >> >> In ordered to fix this problem, I use a state tree for every block >> group to record those allocated spaces. We record the information >> when they are allocated, and clean up the information after the >> metadata update. Besides that, we also introduce a read-write >> semaphore to avoid the race between the allocation and the free >> space cache write out. >> >> Only data block groups had this problem, so the above change is >> just for data space allocation. >> > > I didn't like this idea at first but I've come around to it. The only > thing is the data_rwsem thing, we don't need it as we are protected by > the transaction being blocked when we do writeout, so nobody can data > allocations during this time. Thanks, But this protection was removed by the patch Commit ID: 00361589d2eebd90fca022148c763e40d3e90871 Thanks Miao > > Josef > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1 > Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ > > iQIcBAEBAgAGBQJTFe73AAoJEANb+wAKly3BMMMP/1yY3WBGzaz5oTyNRRSgnVvl > sjk7WSN2A0mhrl6lQOBlTvhgFo3gDNAtIwJaJIfWxWXZfM5i1hXSViFIc5NND3lF > Jm10oaCPiTaYM0S5jqj8oeSXFyb1ny+/D4C1OfC/eRVpu9juO3bFUZYcM1XMFUcI > mJxXg9Mqi1C6TOocCIdQI7ijXgm8xEPauaQy71EJZmgSjjVAXFG9BHay26L2a3Yu > XIlnjyHMcgIFZXGVHQ+45S2pwWVgVZBIHLcKFSDFy4aupq/+EAN15oxdeTLBG8hJ > RFJh15wLQguawlirc7boPzEugSieixbbUjn6CZqikVZke1g1fjGvrTAjiacpTDxv > jskrCPYaXYWKMqGjugsVSI8GSonuWmmVRBsg4k+52U9AYM8wapjL+RHzBXU1cBqu > zfyqaJhBj7EOQIu2oQDT2ZF9E+XA8dLcrysasMS+CYmcmR1Bs1fzpP2W3DoOg68F > YoYuXnaAvIkvUQSsPUNGPjCn+iGCq65ZwiwnwF93RN7zlFIQt12DSn7l/NKnT/p9 > 1jvLkQ2MFmb6QD264mAOL5TULWyyB0AXsitIBJOMs0XWXZheLqqpv1clcaZacBFH > P1yN51+d8DJmF0x0j1HacWi62WnGCh8GzR5ef5Pqi11/11xknbPugrzfFI9v1vR7 > STfhGs/0sg7oQWYgarOj > =Y2df > -----END PGP SIGNATURE----- > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
