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Diffstat (limited to 'open_issues/git-core-2.mdwn')
| -rw-r--r-- | open_issues/git-core-2.mdwn | 92 |
1 files changed, 91 insertions, 1 deletions
diff --git a/open_issues/git-core-2.mdwn b/open_issues/git-core-2.mdwn index 2cac56f2..2d8ad96b 100644 --- a/open_issues/git-core-2.mdwn +++ b/open_issues/git-core-2.mdwn @@ -1,4 +1,4 @@ -[[!meta copyright="Copyright © 2008, 2009, 2010 Free Software Foundation, +[[!meta copyright="Copyright © 2008, 2009, 2010, 2011 Free Software Foundation, Inc."]] [[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable @@ -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 @@ -98,3 +105,86 @@ differences to HEAD. fatal: cannot pread pack file: Interrupted system call fatal: index-pack failed error: Could not fetch savannah + +--- + +2011-06-10, coulomb.SCHWINGE, checking out [[binutils]]' master branch, +starting from an empty working directory (after an external `git push`): + + $ git checkout -f + fatal: cannot create directory at 'gas/testsuite/gas/bfin': Interrupted system call + $ git checkout -f + error: unable to create file gas/testsuite/gas/i386/ilp32/x86-64-sse4_1-intel.d (File exists) + warning: unable to unlink gas/testsuite/gas/m68k-coff: Operation not permitted + fatal: cannot create directory at 'gas/testsuite/gas/m68k-coff': Operation not permitted + $ git checkout -f + error: unable to create file gas/testsuite/gas/h8300/h8300.exp (File exists) + error: unable to create file gas/testsuite/gas/i386/x86-64-addr32-intel.d (File exists) + error: unable to create file gas/testsuite/gas/ia64/secname.d (File exists) + error: unable to create file gas/testsuite/gas/m68k/pr11676.s (File exists) + Checking out files: 100% (12315/12315), done. + $ git status + # On branch master + # Changes not staged for commit: + # (use "git add <file>..." to update what will be committed) + # (use "git checkout -- <file>..." to discard changes in working directory) + # + # modified: gas/testsuite/gas/h8300/h8300.exp + # modified: gas/testsuite/gas/i386/x86-64-addr32-intel.d + # modified: gas/testsuite/gas/ia64/secname.d + # modified: gas/testsuite/gas/m68k/pr11676.s + # + no changes added to commit (use "git add" and/or "git commit -a") + $ rm gas/testsuite/gas/h8300/h8300.exp gas/testsuite/gas/i386/x86-64-addr32-intel.d gas/testsuite/gas/ia64/secname.d gas/testsuite/gas/m68k/pr11676.s + $ git checkout -f + $ git status + # On branch master + nothing to commit (working directory clean) + + +# Analysis + +2011-06-13 + +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? |