diff options
| -rw-r--r-- | open_issues/git-core-2.mdwn | 54 | ||||
| -rw-r--r-- | open_issues/git_duplicated_content.mdwn | 6 |
2 files changed, 57 insertions, 3 deletions
diff --git a/open_issues/git-core-2.mdwn b/open_issues/git-core-2.mdwn index acd82442..2d8ad96b 100644 --- a/open_issues/git-core-2.mdwn +++ b/open_issues/git-core-2.mdwn @@ -13,6 +13,13 @@ License|/fdl]]."]]"""]] [[!tag open_issue_porting]] +[[!toc]] + + +# Log + +December, 2008. + On the otherwise-idle flubber: $ git clone git://sources.redhat.com/git/glibc.git @@ -134,9 +141,50 @@ starting from an empty working directory (after an external `git push`): # On branch master nothing to commit (working directory clean) ---- + +# Analysis 2011-06-13 -This seems to be fixed after a rebuild of the Debian git 1.7.5.3-1 with a -recent toolchain. +Running `git checkout -f` under GDB: + + error: git checkout-index: unable to create file gas/testsuite/gas/cris/string-1.s (File exists) + error: git checkout-index: unable to create file gas/testsuite/gas/i386/x86-64-sse-check.d (File exists) + error: git checkout-index: unable to create file gas/testsuite/gas/i386/x86-64-sse4_1.d (File exists) + error: git checkout-index: unable to create file gas/testsuite/gas/ppc/astest.d (File exists) + error: git checkout-index: unable to create file gas/testsuite/gas/tic6x/reloc-bad-4.s (File exists) + warning: unable to unlink include/cgen: Operation not permitted + fatal: cannot create directory at 'include/cgen': Operation not permitted + +Again: + + error: git checkout-index: unable to create file gas/config/te-vxworks.h (File exists) + error: git checkout-index: unable to create file gas/testsuite/gas/cris/string-1.s (File exists) + error: git checkout-index: unable to create file gas/testsuite/gas/d10v/warning-019.s (File exists) + error: git checkout-index: unable to create file gas/testsuite/gas/i860/dual03.s (File exists) + error: git checkout-index: unable to create file ld/testsuite/ld-mmix/sec-7a.s (File exists) + warning: unable to unlink ld/testsuite/ld-powerpc: Operation not permitted + fatal: cannot create directory at 'ld/testsuite/ld-powerpc': Operation not permitted + +And: [[git_duplicated_content]]. + +All these (very likely) have the same root cause: `SA_RESTART` restarting too +much. + +With `git checkout`, Git uses in progress.c a SIGALRM handler (`SA_RESTART`; +invoked every second via `setitimer(ITIMER_REAL)`) to display status messages: +*x % already checked out*. + +To avoid the status update signals every second, in +`[git]/progress.c:start_progress_delay` we can just return `NULL` (manually in +GDB, for example), then both the *error: git checkout-index* and the +[[duplicated content|git_duplicated_content]] issues go away. + +I'm guessing that when returning from a `SA_RESTART` signal handler, too much +of the \`\`syscall''s is being restarted. For example, if a file has already +been created, the restarted creation attempt would fail: *File exists*. If +data has been written, it might get written again (duplication issue). Then, +there are cases where `unlink` apparently returns EINTR, which is not kosher +either. Etc. + +Do we have problems with `SA_RESTART` vs. the atomicity of our syscall-alikes? diff --git a/open_issues/git_duplicated_content.mdwn b/open_issues/git_duplicated_content.mdwn index 3b4bc44b..cbc171a7 100644 --- a/open_issues/git_duplicated_content.mdwn +++ b/open_issues/git_duplicated_content.mdwn @@ -123,3 +123,9 @@ No further difference. $ rm -rf ar_master* && (cd git/ && git archive master) | (mkdir ar_master && cd ar_master/ && tar -x) && diff -x .git -ru tar_master/ ar_master/ > ar_master.diff; ls -l ar_master.diff $ (cd git/ && git archive master) | md5sum + +--- + +2011-06-13 + +-> [[git-core-2]] |