From 7ec30aaa5ba2a71287879d7bd9a5c55363ea1bbe Mon Sep 17 00:00:00 2001 From: Michael Haggerty Date: Wed, 20 Feb 2013 10:09:24 +0100 Subject: Provide a mechanism to turn off symlink resolution in ceiling paths MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 1b77d83cab 'setup_git_directory_gently_1(): resolve symlinks in ceiling paths' changed the setup code to resolve symlinks in the entries in GIT_CEILING_DIRECTORIES. Because those entries are compared textually to the symlink-resolved current directory, an entry in GIT_CEILING_DIRECTORIES that contained a symlink would have no effect. It was known that this could cause performance problems if the symlink resolution *itself* touched slow filesystems, but it was thought that such use cases would be unlikely. The intention of the earlier change was to deal with a case when the user has this: GIT_CEILING_DIRECTORIES=/home/gitster but in reality, /home/gitster is a symbolic link to somewhere else, e.g. /net/machine/home4/gitster. A textual comparison between the specified value /home/gitster and the location getcwd(3) returns would not help us, but readlink("/home/gitster") would still be fast. After this change was released, Anders Kaseorg reported: > [...] my computer has been acting so slow when I’m not connected to > the network. I put various network filesystem paths in > $GIT_CEILING_DIRECTORIES, such as > /afs/athena.mit.edu/user/a/n/andersk (to avoid hitting its parents > /afs/athena.mit.edu, /afs/athena.mit.edu/user/a, and > /afs/athena.mit.edu/user/a/n which all live in different AFS > volumes). Now when I’m not connected to the network, every > invocation of Git, including the __git_ps1 in my shell prompt, waits > for AFS to timeout. To allow users to work around this problem, give them a mechanism to turn off symlink resolution in GIT_CEILING_DIRECTORIES entries. All the entries that follow an empty entry will not be checked for symbolic links and used literally in comparison. E.g. with these: GIT_CEILING_DIRECTORIES=:/foo/bar:/xyzzy or GIT_CEILING_DIRECTORIES=/foo/bar::/xyzzy we will not readlink("/xyzzy") because it comes after an empty entry. With the former (but not with the latter), "/foo/bar" comes after an empty entry, and we will not readlink it, either. Signed-off-by: Michael Haggerty Signed-off-by: Junio C Hamano --- t/t1504-ceiling-dirs.sh | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 't') diff --git a/t/t1504-ceiling-dirs.sh b/t/t1504-ceiling-dirs.sh index cce87a5ab5..3d51615e42 100755 --- a/t/t1504-ceiling-dirs.sh +++ b/t/t1504-ceiling-dirs.sh @@ -44,6 +44,10 @@ test_prefix ceil_at_sub "" GIT_CEILING_DIRECTORIES="$TRASH_ROOT/sub/" test_prefix ceil_at_sub_slash "" +if test_have_prereq SYMLINKS +then + ln -s sub top +fi mkdir -p sub/dir || exit 1 cd sub/dir || exit 1 @@ -68,6 +72,19 @@ test_fail subdir_ceil_at_sub GIT_CEILING_DIRECTORIES="$TRASH_ROOT/sub/" test_fail subdir_ceil_at_sub_slash +if test_have_prereq SYMLINKS +then + GIT_CEILING_DIRECTORIES="$TRASH_ROOT/top" + test_fail subdir_ceil_at_top + GIT_CEILING_DIRECTORIES="$TRASH_ROOT/top/" + test_fail subdir_ceil_at_top_slash + + GIT_CEILING_DIRECTORIES=":$TRASH_ROOT/top" + test_prefix subdir_ceil_at_top_no_resolve "sub/dir/" + GIT_CEILING_DIRECTORIES=":$TRASH_ROOT/top/" + test_prefix subdir_ceil_at_top_slash_no_resolve "sub/dir/" +fi + GIT_CEILING_DIRECTORIES="$TRASH_ROOT/sub/dir" test_prefix subdir_ceil_at_subdir "sub/dir/" -- cgit v1.2.3