-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 03/05/2014 02:02 AM, Miao Xie wrote: > On Tue, 4 Mar 2014 10:19:20 -0500, Josef Bacik wrote: 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 >
Excellent point, then I'm good overall, I'll pull it in once I finish qgroups. Thanks, Josef -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBAgAGBQJTFzyJAAoJEANb+wAKly3BFHMP+wctKXDuKxP4kI27bfRlfJmV QB5i6qXr4WvQQw04FF3BtxCW9Z36l/1cFLFK0OaQ8Q54+4s0FUXNAynXFkf41TJz XWhkjTq0hJmzM95tB2+B2HwtEDI6m0l6fnOhsyiiSHF8V1g7V9VRwkeqpB9ZGu4/ ZryAUkSJGXFDvtFgTmRvOAclwD0R6oCXCw3f/AgtZQL1H9ucaogI2XKmllllcsFC jOIbn7L+gtFmTAJdvSFlRQAYaV2g69rf0Q5bVHZMAaLKN5rMIXBC2xFOCUxwg3si ZyOl72ojaGbCt7MI/s2X0uZ5d+xWYjaG+tF2K+XLjFoIUkny3RndFfU6pKk54gHP 9O/GXiilq2t3qZUn3zMuLXIG+cCaYTt3QsHnNyJisqOVLL95LbIvsINm0Xgu6bF/ cJ0acApJr6y2EdEbfVU/mrB06K81bxnZez8rOgyFXKD4yWoTMG23xttKZHG5LbdT xkwrJWPeJ77mI0+V/MPWePgomcH5cDs0IckSOXXwy8gZF4HJzVbXklcq22BfgIQA SLVgJYxqIlzIHYHZPisWJHUwFXe4C58YCDP2w4FI32g5LZuzhlus/wFI9Tg1543w sYf23ZYxlDUYAiD+zb+UipEA4CLtdZgZGonoG9lxK9JkgU2VHzXuTgty2+B0F9kt l3B5jpy1H2cP2TUskkbZ =E0en -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
