From 11911bf7c4b4346013be9eefad257a009b659dd2 Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Mon, 5 Oct 2015 22:29:59 +0200 Subject: [PATCH 1/4] t5700: demonstrate a Windows file locking issue with `git clone --dissociate` On Windows, dissociating from a reference can fail very easily due to pack files that are still in use when they want to be removed. Signed-off-by: Johannes Schindelin Signed-off-by: Junio C Hamano --- t/t5700-clone-reference.sh | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/t/t5700-clone-reference.sh b/t/t5700-clone-reference.sh index 3e783fc450..b6c056619c 100755 --- a/t/t5700-clone-reference.sh +++ b/t/t5700-clone-reference.sh @@ -214,5 +214,26 @@ test_expect_success 'clone and dissociate from reference' ' test_must_fail git -C R fsck && git -C S fsck ' +test_expect_failure MINGW 'clone, dissociate from partial reference and repack' ' + rm -fr P Q R && + git init P && + ( + cd P && + test_commit one && + git repack && + test_commit two && + git repack + ) && + git clone --bare P Q && + ( + cd P && + git checkout -b second && + test_commit three && + git repack + ) && + git clone --bare --dissociate --reference=P Q R && + ls R/objects/pack/*.pack >packs.txt && + test_line_count = 1 packs.txt +' test_done From 71fe5d7fb03c0db6edcae39a0312bae2c014a818 Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Mon, 5 Oct 2015 22:30:24 +0200 Subject: [PATCH 2/4] sha1_file: consolidate code to close a pack's file descriptor There was a lot of repeated code to close the file descriptor of a given pack. Let's just refactor this code into a single function. Signed-off-by: Johannes Schindelin Signed-off-by: Junio C Hamano --- sha1_file.c | 38 ++++++++++++++++++-------------------- 1 file changed, 18 insertions(+), 20 deletions(-) diff --git a/sha1_file.c b/sha1_file.c index 99155c0d6b..18922b435e 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -753,6 +753,18 @@ void close_pack_windows(struct packed_git *p) } } +static int close_pack_fd(struct packed_git *p) +{ + if (p->pack_fd < 0) + return 0; + + close(p->pack_fd); + pack_open_fds--; + p->pack_fd = -1; + + return 1; +} + /* * The LRU pack is the one with the oldest MRU window, preferring packs * with no used windows, or the oldest mtime if it has no windows allocated. @@ -820,12 +832,8 @@ static int close_one_pack(void) find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse); } - if (lru_p) { - close(lru_p->pack_fd); - pack_open_fds--; - lru_p->pack_fd = -1; - return 1; - } + if (lru_p) + return close_pack_fd(lru_p); return 0; } @@ -866,10 +874,7 @@ void free_pack_by_name(const char *pack_name) if (strcmp(pack_name, p->pack_name) == 0) { clear_delta_base_cache(); close_pack_windows(p); - if (p->pack_fd != -1) { - close(p->pack_fd); - pack_open_fds--; - } + close_pack_fd(p); close_pack_index(p); free(p->bad_object_sha1); *pp = p->next; @@ -1004,11 +1009,7 @@ static int open_packed_git(struct packed_git *p) { if (!open_packed_git_1(p)) return 0; - if (p->pack_fd != -1) { - close(p->pack_fd); - pack_open_fds--; - p->pack_fd = -1; - } + close_pack_fd(p); return -1; } @@ -1074,11 +1075,8 @@ unsigned char *use_pack(struct packed_git *p, p->pack_name, strerror(errno)); if (!win->offset && win->len == p->pack_size - && !p->do_not_close) { - close(p->pack_fd); - pack_open_fds--; - p->pack_fd = -1; - } + && !p->do_not_close) + close_pack_fd(p); pack_mmap_calls++; pack_open_windows++; if (pack_mapped > peak_pack_mapped) From 38849a8116e690071c02eba0a8ef60a031a58080 Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Tue, 6 Oct 2015 15:18:34 +0200 Subject: [PATCH 3/4] sha1_file.c: add a function to release all packs On Windows, files that are in use cannot be removed or renamed. That means that we have to release pack files when we are about to, say, repack them. Let's introduce a convenient function to close all the pack files and their idx files. While at it, we consolidate the close windows/close fd/close index stanza in `free_pack_by_name()` into the `close_pack()` function that is used by the new `close_all_packs()` function to avoid repeated code. Signed-off-by: Johannes Schindelin Signed-off-by: Junio C Hamano --- cache.h | 1 + sha1_file.c | 23 ++++++++++++++++++++--- 2 files changed, 21 insertions(+), 3 deletions(-) diff --git a/cache.h b/cache.h index 4427945bc0..c3a2bb8aff 100644 --- a/cache.h +++ b/cache.h @@ -1231,6 +1231,7 @@ extern void close_pack_index(struct packed_git *); extern unsigned char *use_pack(struct packed_git *, struct pack_window **, off_t, unsigned long *); extern void close_pack_windows(struct packed_git *); +extern void close_all_packs(void); extern void unuse_pack(struct pack_window **); extern void free_pack_by_name(const char *); extern void clear_delta_base_cache(void); diff --git a/sha1_file.c b/sha1_file.c index 18922b435e..d215e0c9bf 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -765,6 +765,25 @@ static int close_pack_fd(struct packed_git *p) return 1; } +static void close_pack(struct packed_git *p) +{ + close_pack_windows(p); + close_pack_fd(p); + close_pack_index(p); +} + +void close_all_packs(void) +{ + struct packed_git *p; + + for (p = packed_git; p; p = p->next) + if (p->do_not_close) + die("BUG! Want to close pack marked 'do-not-close'"); + else + close_pack(p); +} + + /* * The LRU pack is the one with the oldest MRU window, preferring packs * with no used windows, or the oldest mtime if it has no windows allocated. @@ -873,9 +892,7 @@ void free_pack_by_name(const char *pack_name) p = *pp; if (strcmp(pack_name, p->pack_name) == 0) { clear_delta_base_cache(); - close_pack_windows(p); - close_pack_fd(p); - close_pack_index(p); + close_pack(p); free(p->bad_object_sha1); *pp = p->next; if (last_found_pack == p) From 786b150c8d0960cb7c36fb1cbbf70dbd76b586de Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Tue, 6 Oct 2015 15:18:47 +0200 Subject: [PATCH 4/4] clone --dissociate: avoid locking pack files When `git clone` is asked to dissociate the repository from the reference repository whose objects were used, it is quite possible that the pack files need to be repacked. In that case, the pack files need to be deleted that were originally hard-links to the reference repository's pack files. On platforms where a file cannot be deleted if another process still holds a handle on it, we therefore need to take pains to release all pack files and indexes before dissociating. This fixes https://github.com/git-for-windows/git/issues/446 The test case to demonstrate the breakage technically does not need to be run on Linux or MacOSX. It won't hurt, either, though. Signed-off-by: Johannes Schindelin Signed-off-by: Junio C Hamano --- builtin/clone.c | 4 +++- t/t5700-clone-reference.sh | 2 +- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/builtin/clone.c b/builtin/clone.c index e18839d107..6633d87038 100644 --- a/builtin/clone.c +++ b/builtin/clone.c @@ -995,8 +995,10 @@ int cmd_clone(int argc, const char **argv, const char *prefix) transport_unlock_pack(transport); transport_disconnect(transport); - if (option_dissociate) + if (option_dissociate) { + close_all_packs(); dissociate_from_references(); + } junk_mode = JUNK_LEAVE_REPO; err = checkout(); diff --git a/t/t5700-clone-reference.sh b/t/t5700-clone-reference.sh index b6c056619c..057da59ae0 100755 --- a/t/t5700-clone-reference.sh +++ b/t/t5700-clone-reference.sh @@ -214,7 +214,7 @@ test_expect_success 'clone and dissociate from reference' ' test_must_fail git -C R fsck && git -C S fsck ' -test_expect_failure MINGW 'clone, dissociate from partial reference and repack' ' +test_expect_success 'clone, dissociate from partial reference and repack' ' rm -fr P Q R && git init P && (