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2014-10-19reachable: use revision machinery's --indexed-objects codeLibravatar Jeff King1-51/+1
This does the same thing as our custom code, so let's not repeat ourselves. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-16pack-objects: match prune logic for discarding objectsLibravatar Jeff King1-2/+2
A recent commit taught git-prune to keep non-recent objects that are reachable from recent ones. However, pack-objects, when loosening unreachable objects, tries to optimize out the write in the case that the object will be immediately pruned. It now gets this wrong, since its rule does not reflect the new prune code (and this can be seen by running t6501 with a strategically placed repack). Let's teach pack-objects similar logic. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-16prune: keep objects reachable from recent objectsLibravatar Jeff King1-0/+112
Our current strategy with prune is that an object falls into one of three categories: 1. Reachable (from ref tips, reflogs, index, etc). 2. Not reachable, but recent (based on the --expire time). 3. Not reachable and not recent. We keep objects from (1) and (2), but prune objects in (3). The point of (2) is that these objects may be part of an in-progress operation that has not yet updated any refs. However, it is not always the case that objects for an in-progress operation will have a recent mtime. For example, the object database may have an old copy of a blob (from an abandoned operation, a branch that was deleted, etc). If we create a new tree that points to it, a simultaneous prune will leave our tree, but delete the blob. Referencing that tree with a commit will then work (we check that the tree is in the object database, but not that all of its referred objects are), as will mentioning the commit in a ref. But the resulting repo is corrupt; we are missing the blob reachable from a ref. One way to solve this is to be more thorough when referencing a sha1: make sure that not only do we have that sha1, but that we have objects it refers to, and so forth recursively. The problem is that this is very expensive. Creating a parent link would require traversing the entire object graph! Instead, this patch pushes the extra work onto prune, which runs less frequently (and has to look at the whole object graph anyway). It creates a new category of objects: objects which are not recent, but which are reachable from a recent object. We do not prune these objects, just like the reachable and recent ones. This lets us avoid the recursive check above, because if we have an object, even if it is unreachable, we should have its referent. We can make a simple inductive argument that with this patch, this property holds (that there are no objects with missing referents in the repository): 0. When we have no objects, we have nothing to refer or be referred to, so the property holds. 1. If we add objects to the repository, their direct referents must generally exist (e.g., if you create a tree, the blobs it references must exist; if you create a commit to point at the tree, the tree must exist). This is already the case before this patch. And it is not 100% foolproof (you can make bogus objects using `git hash-object`, for example), but it should be the case for normal usage. Therefore for any sequence of object additions, the property will continue to hold. 2. If we remove objects from the repository, then we will not remove a child object (like a blob) if an object that refers to it is being kept. That is the part implemented by this patch. Note, however, that our reachability check and the actual pruning are not atomic. So it _is_ still possible to violate the property (e.g., an object becomes referenced just as we are deleting it). This patch is shooting for eliminating problems where the mtimes of dependent objects differ by hours or days, and one is dropped without the other. It does nothing to help with short races. Naively, the simplest way to implement this would be to add all recent objects as tips to the reachability traversal. However, this does not perform well. In a recently-packed repository, all reachable objects will also be recent, and therefore we have to look at each object twice. This patch instead performs the reachability traversal, then follows up with a second traversal for recent objects, skipping any that have already been marked. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-16reachable: mark index blobs as SEENLibravatar Jeff King1-1/+6
When we mark all reachable objects for pruning, that includes blobs mentioned by the index. However, we do not mark these with the SEEN flag, as we do for objects that we find by traversing (we also do not add them to the pending list, but that is because there is nothing further to traverse with them). This doesn't cause any problems with prune, because it checks only that the object exists in the global object hash, and not its flags. However, let's mark these objects to be consistent and avoid any later surprises. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-16reachable: reuse revision.c "add all reflogs" codeLibravatar Jeff King1-23/+1
We want to add all reflog entries as tips for finding reachable objects. The revision machinery can already do this (to support "rev-list --reflog"); we can reuse that code. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-16reachable: use traverse_commit_list instead of custom walkLibravatar Jeff King1-113/+17
To find the set of reachable objects, we add a bunch of possible sources to our rev_info, call prepare_revision_walk, and then launch into a custom walker that handles each object top. This is a subset of what traverse_commit_list does, so we can just reuse that code (it can also handle more complex cases like UNINTERESTING commits and pathspecs, but we don't use those features). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-09-03reachable.c: add HEAD to reachability starting commitsLibravatar Max Kirillov1-0/+3
HEAD is not explicitly used as a starting commit for calculating reachability, so if it's detached and reflogs are disabled it may be pruned. Add tests which demonstrate it. Test 'prune: prune former HEAD after checking out branch' also reverts changes to repository. Signed-off-by: Max Kirillov <max@max630.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-06-06clear parsed flag when we free tree buffersLibravatar Jeff King1-2/+1
Many code paths will free a tree object's buffer and set it to NULL after finishing with it in order to keep memory usage down during a traversal. However, out of 8 sites that do this, only one actually unsets the "parsed" flag back. Those sites that don't are setting a trap for later users of the tree object; even after calling parse_tree, the buffer will remain NULL, causing potential segfaults. It is not known whether this is triggerable in the current code. Most commands do not do an in-memory traversal followed by actually using the objects again. However, it does not hurt to be safe for future callers. In most cases, we can abstract this out to a "free_tree_buffer" helper. However, there are two exceptions: 1. The fsck code relies on the parsed flag to know that we were able to parse the object at one point. We can switch this to using a flag in the "flags" field. 2. The index-pack code sets the buffer to NULL but does not free it (it is freed by a caller). We should still unset the parsed flag here, but we cannot use our helper, as we do not want to free the buffer. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-03-17use parse_object_or_die instead of die("bad object")Libravatar Jeff King1-3/+1
Some call-sites do: o = parse_object(sha1); if (!o) die("bad object %s", some_name); We can now handle that as a one-liner, and get more consistent output. In the third case of this patch, it looks like we are losing information, as the existing message also outputs the sha1 hex; however, parse_object will already have written a more specific complaint about the sha1, so there is no point in repeating it here. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-11-07reachable: per-object progressLibravatar Jeff King1-14/+37
The current progress code really just counts commits. This patch makes it count all objects, giving us a "total" count close to what a repack would show. This is nice when using "git gc", which will usually have just repacked the whole repo. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-11-07prune: show progress while marking reachable objectsLibravatar Nguyễn Thái Ngọc Duy1-4/+10
prune already shows progress meter while pruning. The marking part may take a few seconds or more, depending on repository size. Show progress meter during this time too. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-03-22Remove unused variablesLibravatar Johannes Schindelin1-5/+0
Noticed by gcc 4.6.0. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-08-29object.h: Add OBJECT_ARRAY_INIT macro and make use of it.Libravatar Thiago Farina1-1/+1
Signed-off-by: Thiago Farina <tfransosi@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-04-08process_{tree,blob}: Remove useless xstrdup callsLibravatar Björn Steinbrink1-1/+0
The name of the processed object was duplicated for passing it to add_object(), but that already calls path_name, which allocates a new string anyway. So the memory allocated by the xstrdup calls just went nowhere, leaking memory. This reduces the RSS usage for a "rev-list --all --objects" by about 10% on the gentoo repo (fully packed) as well as linux-2.6.git: gentoo: | old | new ----------------|------------------------------- RSS | 1537284 | 1388408 VSZ | 1816852 | 1667952 time elapsed | 1:49.62 | 1:48.99 min. page faults| 417178 | 379919 linux-2.6.git: | old | new ----------------|------------------------------- RSS | 324452 | 292996 VSZ | 491792 | 460376 time elapsed | 0:14.53 | 0:14.28 min. page faults| 89360 | 81613 Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-02-18Merge branch 'mk/maint-parse-careful'Libravatar Junio C Hamano1-2/+8
* mk/maint-parse-careful: peel_onion: handle NULL check return value from parse_commit() in various functions parse_commit: don't fail, if object is NULL revision.c: handle tag->tagged == NULL reachable.c::process_tree/blob: check for NULL process_tag: handle tag->tagged == NULL check results of parse_commit in merge_bases list-objects.c::process_tree/blob: check for NULL reachable.c::add_one_tree: handle NULL from lookup_tree mark_blob/tree_uninteresting: check for NULL get_sha1_oneline: check return value of parse_object read_object_with_reference: don't read beyond the buffer
2008-02-18reachable.c::process_tree/blob: check for NULLLibravatar Martin Koegler1-0/+4
As these functions are directly called with the result from lookup_tree/blob, they must handle NULL. Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-02-18process_tag: handle tag->tagged == NULLLibravatar Martin Koegler1-1/+2
Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-02-18reachable.c::add_one_tree: handle NULL from lookup_treeLibravatar Martin Koegler1-1/+2
Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-02-17check return code of prepare_revision_walkLibravatar Martin Koegler1-1/+2
A failure in prepare_revision_walk can be caused by a not parseable object. Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-01-21Make on-disk index representation separate from in-core oneLibravatar Linus Torvalds1-1/+1
This converts the index explicitly on read and write to its on-disk format, allowing the in-core format to contain more flags, and be simpler. In particular, the in-core format is now host-endian (as opposed to the on-disk one that is network endian in order to be able to be shared across machines) and as a result we can dispense with all the htonl/ntohl on accesses to the cache_entry fields. This will make it easier to make use of various temporary flags that do not exist in the on-disk format. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-02Merge branch 'maint'Libravatar Junio C Hamano1-0/+20
* maint: Make git-prune submodule aware (and fix a SEGFAULT in the process)
2007-07-02Make git-prune submodule aware (and fix a SEGFAULT in the process)Libravatar Andy Parkins1-0/+20
I ran git-prune on a repository and got this: $ git-prune error: Object 228f8065b930120e35fc0c154c237487ab02d64a is a blob, not a commit Segmentation fault (core dumped) This repository was a strange one in that it was being used to provide its own submodule. That is, the repository was cloned into a subdirectory, an independent branch checked out in that subdirectory, and then it was marked as a submodule. git-prune then failed in the above manner. The problem was that git-prune was not submodule aware in two areas. Linus said: > So what happens is that something traverses a tree object, looks at each > entry, sees that it's not a tree, and tries to look it up as a blob. But > subprojects are commits, not blobs, and then when you look at the object > more closely, you get the above kind of object type confusion. and included a patch to add an S_ISGITLINK() test to reachable.c's process_tree() function. That fixed the first git-prune error, and stopped it from trying to process the gitlink entries in trees as if they were pointers to other trees (and of course failing, because gitlinks _aren't_ trees). That part of this patch is his. The second area is add_cache_refs(). This is called before starting the reachability analysis, and was calling lookup_blob() on every object hash found in the index. However, it is no longer true that every hash in the index is a pointer to a blob, some of them are gitlinks, and are not backed by any object at all, they are commits in another repository. Normally this bug was not causing any problems, but in the case of the self-referencing repository described above, it meant that the gitlink hash was being marked as being of type OBJ_BLOB by add_cache_refs() call to lookup_blob(). Then later, because that hash was also pointed to by a ref, add_one_ref() would treat it as a commit; lookup_commit() would return a NULL because that object was already noted as being an OBJ_BLOB, not an OBJ_COMMIT; and parse_commit_buffer() would SEGFAULT on that NULL pointer. The fix made by this patch is to not blindly call lookup_blob() in reachable.c's add_cache_refs(), and instead skip any index entries that are S_ISGITLINK(). Signed-off-by: Andy Parkins <andyparkins@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-03-21Initialize tree descriptors with a helper function rather than by hand.Libravatar Linus Torvalds1-2/+1
This removes slightly more lines than it adds, but the real reason for doing this is that future optimizations will require more setup of the tree descriptor, and so we want to do it in one place. Also renamed the "desc.buf" field to "desc.buffer" just to trigger compiler errors for old-style manual initializations, making sure I didn't miss anything. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-02-03scan reflogs independently from refsLibravatar Nicolas Pitre1-2/+2
Currently, the search for all reflogs depends on the existence of corresponding refs under the .git/refs/ directory. Let's scan the .git/logs/ directory directly instead. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-01-09Sanitize for_each_reflog_ent()Libravatar Johannes Schindelin1-1/+3
It used to ignore the return value of the helper function; now, it expects it to return 0, and stops iteration upon non-zero return values; this value is then passed on as the return value of for_each_reflog_ent(). Further, it makes no sense to force the parsing upon the helper functions; for_each_reflog_ent() now calls the helper function with old and new sha1, the email, the timestamp & timezone, and the message. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-01-06Move traversal of reachable objects into a separate library.Libravatar Junio C Hamano1-0/+199
This moves major part of builtin-prune into a separate file, reachable.c. It is used to mark the objects that are reachable from refs, and optionally from reflogs. The patch looks very large, but if you look at it with diff -C, which this message is formatted in, most of them are copied lines and there are very little additions. Signed-off-by: Junio C Hamano <junkio@cox.net>