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author | 2017-06-06 14:21:43 -0400 | |
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committer | 2017-06-06 14:22:03 -0400 | |
commit | 6b986240d9397563a888e40edc3c11857b36a4c3 (patch) | |
tree | 3de97c86c6af36391e81b11c785ce032c27a41f1 /doc/bugs/SMB__58___git_annex_clone_works__44___get_fails_on_transfer_lock/comment_5_8b5d03f64127aa6b4073ff10796b9771._comment | |
parent | e57492d980d410eec4956b3df8c495c03a356666 (diff) |
Fix bug that prevented transfer locks from working when run on SMB or other filesystem that does not support fcntl locks and hard links.
This commit was sponsored by Ethan Aubin.
Diffstat (limited to 'doc/bugs/SMB__58___git_annex_clone_works__44___get_fails_on_transfer_lock/comment_5_8b5d03f64127aa6b4073ff10796b9771._comment')
-rw-r--r-- | doc/bugs/SMB__58___git_annex_clone_works__44___get_fails_on_transfer_lock/comment_5_8b5d03f64127aa6b4073ff10796b9771._comment | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/doc/bugs/SMB__58___git_annex_clone_works__44___get_fails_on_transfer_lock/comment_5_8b5d03f64127aa6b4073ff10796b9771._comment b/doc/bugs/SMB__58___git_annex_clone_works__44___get_fails_on_transfer_lock/comment_5_8b5d03f64127aa6b4073ff10796b9771._comment new file mode 100644 index 000000000..64b1feb8b --- /dev/null +++ b/doc/bugs/SMB__58___git_annex_clone_works__44___get_fails_on_transfer_lock/comment_5_8b5d03f64127aa6b4073ff10796b9771._comment @@ -0,0 +1,59 @@ +[[!comment format=mdwn + username="joey" + subject="""comment 5""" + date="2017-06-06T17:54:42Z" + content=""" +Here's the relevant parts of the dtruss: + + 7003/0x16c3126: 121483 3371 127 open("/Volumes/music/ga-test/.git/annex/locktmp16807282475249\0", 0x20A06, 0x180) = 18 0 + ... + 7003/0x16c3126: 121792 10 6 stat64("/Volumes/music/ga-test/.git/annex/locktmp16807282475249\0", 0x200004940, 0x33) = 0 0 + 7003/0x16c3126: 122041 2341 235 link("/Volumes/music/ga-test/.git/annex/locktmp16807282475249\0", "/Volumes/music/ga-test/.git/annex/locktmp16807282475249.lnk\0") = -1 Err#45 + 7003/0x16c3126: 122115 885 49 unlink("/Volumes/music/ga-test/.git/annex/locktmp16807282475249.lnk\0", 0x200004D80, 0x33) = -1 Err#2 + 7003/0x16c3126: 122126 5 1 sigreturn(0x7FFF56C9E390, 0x1E, 0x33) = 0 Err#-2 + 7003/0x16c3126: 122247 1050 90 open("/Volumes/music/ga-test/.git/annex/pidlock\0", 0xA01, 0x124) = 18 0 + 7003/0x16c3126: 122256 4 1 fcntl(0x12, 0x3, 0x0) = 1 0 + 7003/0x16c3126: 122260 5 2 fstat64(0x12, 0x20001A120, 0x0) = 0 0 + 7003/0x16c3126: 122273 4 1 ioctl(0x12, 0x4004667A, 0x7FFF56C9E3FC) = -1 Err#25 + 7003/0x16c3126: 122274 2 0 ioctl(0x12, 0x40487413, 0x7FFF56C9E400) = -1 Err#25 + 7003/0x16c3126: 122314 677 32 open("/Volumes/music/ga-test/.git/annex/locktmp16807282475249\0", 0x20004, 0x1B6) = 19 0 + 7003/0x16c3126: 122319 5 2 fstat64(0x13, 0x20001A310, 0x1B6) = 0 0 + 7003/0x16c3126: 122326 2 0 ioctl(0x13, 0x4004667A, 0x7FFF56C9E3FC) = -1 Err#25 + 7003/0x16c3126: 122327 2 0 ioctl(0x13, 0x40487413, 0x7FFF56C9E400) = -1 Err#25 + 7003/0x16c3126: 122381 1455 46 read(0x13, "PidLock {lockingPid = 7003, lockingHost = \"ashram\"}\0", 0x1FA0) = 51 0 + 7003/0x16c3126: 122392 5 2 read(0x13, "\0", 0x1FA0) = 0 0 + 7003/0x16c3126: 122427 1339 27 close(0x13) = 0 0 + 7003/0x16c3126: 122441 10 4 select(0x13, 0x7FFF56C9E340, 0x7FFF56C9E3C0, 0x0, 0x7FFF56C9E330) = 1 0 + 7003/0x16c3126: 122469 661 23 write(0x12, "PidLock {lockingPid = 7003, lockingHost = \"ashram\"}\0", 0x33) = 51 0 + 7003/0x16c3126: 122577 6028 99 close(0x12) = 0 0 + +Avove shows hard linking failed, and it fell back to using open to create +the pidlock file. That seemed to finish successfully. + + 7003/0x16c3126: 122583 4 0 sigreturn(0x7FFF56C9E3B0, 0x1E, 0x33) = 0 Err#-2 + +Unsure what this is? + + 7003/0x16c3126: 122697 2126 101 unlink("/Volumes/music/ga-test/.git/annex/locktmp16807282475249\0", 0x1E, 0x33) = 0 0 + +Here linkToLock must has succeeded, because it deletes the tmp file that was passed to that function. +So, it looks like tryLock succeeded. + + 7003/0x16c3126: 122746 1423 28 stat64(".git/annex/pidlock\0", 0x20001A510, 0x33) = 0 0 + 7003/0x16c3126: 122775 10 5 select(0x2, 0x7FFF56C9E340, 0x7FFF56C9E3C0, 0x0, 0x7FFF56C9E330) = 1 0 + 7003/0x16c3126: 122786 10 8 write(0x1, "(transfer already in progress, or unable to take transfer lock) \0", 0x40) = 64 0 + +I think this is a call to checkSaneLock, which calls getFileStatus, +and since the pid lock was created earlier, that succeeds. +runTransfer does call checkSaneLock, and if it fails +we get the "transfer already in progress, or unable to take transfer lock" +message. + +So, why did checkSaneLock fail? + +Well, the device and inode of the lock file +are compared with the device and inode of the temp file +that was passed to linkToLock. However, since the hard link didn't +happen, the device and inode will be different! +And that's the bug. +"""]] |