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2021-04-28repack: avoid loosening promisor objects in partial clonesLibravatar Rafael Silva1-2/+7
When `git repack -A -d` is run in a partial clone, `pack-objects` is invoked twice: once to repack all promisor objects, and once to repack all non-promisor objects. The latter `pack-objects` invocation is with --exclude-promisor-objects and --unpack-unreachable, which loosens all objects unused during this invocation. Unfortunately, this includes promisor objects. Because the -d argument to `git repack` subsequently deletes all loose objects also in packs, these just-loosened promisor objects will be immediately deleted. However, this extra disk churn is unnecessary in the first place. For example, in a newly-cloned partial repo that filters all blob objects (e.g. `--filter=blob:none`), `repack` ends up unpacking all trees and commits into the filesystem because every object, in this particular case, is a promisor object. Depending on the repo size, this increases the disk usage considerably: In my copy of the linux.git, the object directory peaked 26GB of more disk usage. In order to avoid this extra disk churn, pass the names of the promisor packfiles as --keep-pack arguments to the second invocation of `pack-objects`. This informs `pack-objects` that the promisor objects are already in a safe packfile and, therefore, do not need to be loosened. For testing, we need to validate whether any object was loosened. However, the "evidence" (loosened objects) is deleted during the process which prevents us from inspecting the object directory. Instead, let's teach `pack-objects` to count loosened objects and emit via trace2 thus allowing inspecting the debug events after the process is finished. This new event is used on the added regression test. Lastly, add a new perf test to evaluate the performance impact made by this changes (tested on git.git): Test HEAD^ HEAD ---------------------------------------------------------- 5600.3: gc 134.38(41.93+90.95) 7.80(6.72+1.35) -94.2% For a bigger repository, such as linux.git, the improvement is even bigger: Test HEAD^ HEAD ------------------------------------------------------------------- 5600.3: gc 6833.00(918.07+3162.74) 268.79(227.02+39.18) -96.1% These improvements are particular big because every object in the newly-cloned partial repository is a promisor object. Reported-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jeff King <peff@peff.net> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Rafael Silva <rafaeloliveira.cs@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-08Merge branch 'tb/reverse-midx'Libravatar Junio C Hamano1-1/+1
An on-disk reverse-index to map the in-pack location of an object back to its object name across multiple packfiles is introduced. * tb/reverse-midx: midx.c: improve cache locality in midx_pack_order_cmp() pack-revindex: write multi-pack reverse indexes pack-write.c: extract 'write_rev_file_order' pack-revindex: read multi-pack reverse indexes Documentation/technical: describe multi-pack reverse indexes midx: make some functions non-static midx: keep track of the checksum midx: don't free midx_name early midx: allow marking a pack as preferred t/helper/test-read-midx.c: add '--show-objects' builtin/multi-pack-index.c: display usage on unrecognized command builtin/multi-pack-index.c: don't enter bogus cmd_mode builtin/multi-pack-index.c: split sub-commands builtin/multi-pack-index.c: define common usage with a macro builtin/multi-pack-index.c: don't handle 'progress' separately builtin/multi-pack-index.c: inline 'flags' with options
2021-04-01midx: allow marking a pack as preferredLibravatar Taylor Blau1-1/+1
When multiple packs in the multi-pack index contain the same object, the MIDX machinery must make a choice about which pack it associates with that object. Prior to this patch, the lowest-ordered[1] pack was always selected. Pack selection for duplicate objects is relatively unimportant today, but it will become important for multi-pack bitmaps. This is because we can only invoke the pack-reuse mechanism when all of the bits for reused objects come from the reuse pack (in order to ensure that all reused deltas can find their base objects in the same pack). To encourage the pack selection process to prefer one pack over another (the pack to be preferred is the one a caller would like to later use as a reuse pack), introduce the concept of a "preferred pack". When provided, the MIDX code will always prefer an object found in a preferred pack over any other. No format changes are required to store the preferred pack, since it will be able to be inferred with a corresponding MIDX bitmap, by looking up the pack associated with the object in the first bit position (this ordering is described in detail in a subsequent commit). [1]: the ordering is specified by MIDX internals; for our purposes we can consider the "lowest ordered" pack to be "the one with the most-recent mtime. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-05builtin/repack.c: reword comment around pack-objects flagsLibravatar Junio C Hamano1-5/+7
The comment in this block is meant to indicate that passing '--all', '--reflog', and so on aren't necessary when repacking with the '--geometric' option. But, it has two problems: first, it is factually incorrect ('--all' is *not* incompatible with '--stdin-packs' as the comment suggests); second, it is quite focused on the geometric case for a block that is guarding against it. Reword this comment to address both issues. Signed-off-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-05builtin/repack.c: be more conservative with unsigned overflowsLibravatar Taylor Blau1-2/+22
There are a number of places in the geometric repack code where we multiply the number of objects in a pack by another unsigned value. We trust that the number of objects in a pack is always representable by a uint32_t, but we don't necessarily trust that that number can be multiplied without overflow. Sprinkle some unsigned_add_overflows() and unsigned_mult_overflows() in split_pack_geometry() to check that we never overflow any unsigned types when adding or multiplying them. Arguably these checks are a little too conservative, and certainly they do not help the readability of this function. But they are serving a useful purpose, so I think they are worthwhile overall. Suggested-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-05builtin/repack.c: assign pack split laterLibravatar Taylor Blau1-5/+3
To determine the where to place the split when repacking with the '--geometric' option, split_pack_geometry() assigns the "split" variable and then decrements it in a loop. It would be equivalent (and more readable) to assign the split to the loop position after exiting the loop, so do that instead. Suggested-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-05builtin/repack.c: do not repack single packs with --geometricLibravatar Taylor Blau1-1/+1
In 0fabafd0b9 (builtin/repack.c: add '--geometric' option, 2021-02-22), the 'git repack --geometric' code aborts early when there is zero or one pack. When there are no packs, this code does the right thing by placing the split at "0". But when there is exactly one pack, the split is placed at "1", which means that "git repack --geometric" (with any factor) repacks all of the objects in a single pack. This is wasteful, and the remaining code in split_pack_geometry() does the right thing (not repacking the objects in a single pack) even when only one pack is present. Loosen the guard to only stop when there aren't any packs, and let the rest of the code do the right thing. Add a test to ensure that this is the case. Noticed-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-22builtin/repack.c: add '--geometric' optionLibravatar Taylor Blau1-4/+183
Often it is useful to both: - have relatively few packfiles in a repository, and - avoid having so few packfiles in a repository that we repack its entire contents regularly This patch implements a '--geometric=<n>' option in 'git repack'. This allows the caller to specify that they would like each pack to be at least a factor times as large as the previous largest pack (by object count). Concretely, say that a repository has 'n' packfiles, labeled P1, P2, ..., up to Pn. Each packfile has an object count equal to 'objects(Pn)'. With a geometric factor of 'r', it should be that: objects(Pi) > r*objects(P(i-1)) for all i in [1, n], where the packs are sorted by objects(P1) <= objects(P2) <= ... <= objects(Pn). Since finding a true optimal repacking is NP-hard, we approximate it along two directions: 1. We assume that there is a cutoff of packs _before starting the repack_ where everything to the right of that cut-off already forms a geometric progression (or no cutoff exists and everything must be repacked). 2. We assume that everything smaller than the cutoff count must be repacked. This forms our base assumption, but it can also cause even the "heavy" packs to get repacked, for e.g., if we have 6 packs containing the following number of objects: 1, 1, 1, 2, 4, 32 then we would place the cutoff between '1, 1' and '1, 2, 4, 32', rolling up the first two packs into a pack with 2 objects. That breaks our progression and leaves us: 2, 1, 2, 4, 32 ^ (where the '^' indicates the position of our split). To restore a progression, we move the split forward (towards larger packs) joining each pack into our new pack until a geometric progression is restored. Here, that looks like: 2, 1, 2, 4, 32 ~> 3, 2, 4, 32 ~> 5, 4, 32 ~> ... ~> 9, 32 ^ ^ ^ ^ This has the advantage of not repacking the heavy-side of packs too often while also only creating one new pack at a time. Another wrinkle is that we assume that loose, indexed, and reflog'd objects are insignificant, and lump them into any new pack that we create. This can lead to non-idempotent results. Suggested-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Reviewed-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-25packfile: prepare for the existence of '*.rev' filesLibravatar Taylor Blau1-0/+1
Specify the format of the on-disk reverse index 'pack-*.rev' file, as well as prepare the code for the existence of such files. The reverse index maps from pack relative positions (i.e., an index into the array of object which is sorted by their offsets within the packfile) to their position within the 'pack-*.idx' file. Today, this is done by building up a list of (off_t, uint32_t) tuples for each object (the off_t corresponding to that object's offset, and the uint32_t corresponding to its position in the index). To convert between pack and index position quickly, this array of tuples is radix sorted based on its offset. This has two major drawbacks: First, the in-memory cost scales linearly with the number of objects in a pack. Each 'struct revindex_entry' is sizeof(off_t) + sizeof(uint32_t) + padding bytes for a total of 16. To observe this, force Git to load the reverse index by, for e.g., running 'git cat-file --batch-check="%(objectsize:disk)"'. When asking for a single object in a fresh clone of the kernel, Git needs to allocate 120+ MB of memory in order to hold the reverse index in memory. Second, the cost to sort also scales with the size of the pack. Luckily, this is a linear function since 'load_pack_revindex()' uses a radix sort, but this cost still must be paid once per pack per process. As an example, it takes ~60x longer to print the _size_ of an object as it does to print that entire object's _contents_: Benchmark #1: git.compile cat-file --batch <obj Time (mean ± σ): 3.4 ms ± 0.1 ms [User: 3.3 ms, System: 2.1 ms] Range (min … max): 3.2 ms … 3.7 ms 726 runs Benchmark #2: git.compile cat-file --batch-check="%(objectsize:disk)" <obj Time (mean ± σ): 210.3 ms ± 8.9 ms [User: 188.2 ms, System: 23.2 ms] Range (min … max): 193.7 ms … 224.4 ms 13 runs Instead, avoid computing and sorting the revindex once per process by writing it to a file when the pack itself is generated. The format is relatively straightforward. It contains an array of uint32_t's, the length of which is equal to the number of objects in the pack. The ith entry in this table contains the index position of the ith object in the pack, where "ith object in the pack" is determined by pack offset. One thing that the on-disk format does _not_ contain is the full (up to) eight-byte offset corresponding to each object. This is something that the in-memory revindex contains (it stores an off_t in 'struct revindex_entry' along with the same uint32_t that the on-disk format has). Omit it in the on-disk format, since knowing the index position for some object is sufficient to get a constant-time lookup in the pack-*.idx file to ask for an object's offset within the pack. This trades off between the on-disk size of the 'pack-*.rev' file for runtime to chase down the offset for some object. Even though the lookup is constant time, the constant is heavier, since it can potentially involve two pointer walks in v2 indexes (one to access the 4-byte offset table, and potentially a second to access the double wide offset table). Consider trying to map an object's pack offset to a relative position within that pack. In a cold-cache scenario, more page faults occur while switching between binary searching through the reverse index and searching through the *.idx file for an object's offset. Sure enough, with a cold cache (writing '3' into '/proc/sys/vm/drop_caches' after 'sync'ing), printing out the entire object's contents is still marginally faster than printing its size: Benchmark #1: git.compile cat-file --batch-check="%(objectsize:disk)" <obj >/dev/null Time (mean ± σ): 22.6 ms ± 0.5 ms [User: 2.4 ms, System: 7.9 ms] Range (min … max): 21.4 ms … 23.5 ms 41 runs Benchmark #2: git.compile cat-file --batch <obj >/dev/null Time (mean ± σ): 17.2 ms ± 0.7 ms [User: 2.8 ms, System: 5.5 ms] Range (min … max): 15.6 ms … 18.2 ms 45 runs (Numbers taken in the kernel after cheating and using the next patch to generate a reverse index). There are a couple of approaches to improve cold cache performance not pursued here: - We could include the object offsets in the reverse index format. Predictably, this does result in fewer page faults, but it triples the size of the file, while simultaneously duplicating a ton of data already available in the .idx file. (This was the original way I implemented the format, and it did show `--batch-check='%(objectsize:disk)'` winning out against `--batch`.) On the other hand, this increase in size also results in a large block-cache footprint, which could potentially hurt other workloads. - We could store the mapping from pack to index position in more cache-friendly way, like constructing a binary search tree from the table and writing the values in breadth-first order. This would result in much better locality, but the price you pay is trading O(1) lookup in 'pack_pos_to_index()' for an O(log n) one (since you can no longer directly index the table). So, neither of these approaches are taken here. (Thankfully, the format is versioned, so we are free to pursue these in the future.) But, cold cache performance likely isn't interesting outside of one-off cases like asking for the size of an object directly. In real-world usage, Git is often performing many operations in the revindex (i.e., asking about many objects rather than a single one). The trade-off is worth it, since we will avoid the vast majority of the cost of generating the revindex that the extra pointer chase will look like noise in the following patch's benchmarks. This patch describes the format and prepares callers (like in pack-revindex.c) to be able to read *.rev files once they exist. An implementation of the writer will appear in the next patch, and callers will gradually begin to start using the writer in the patches that follow after that. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12fetch-pack: refactor writing promisor fileLibravatar Christian Couder1-5/+3
Let's replace the 2 different pieces of code that write a promisor file in 'builtin/repack.c' and 'fetch-pack.c' with a new function called 'write_promisor_file()' in 'pack-write.c' and 'pack.h'. This might also help us in the future, if we want to put back the ref names and associated hashes that were in the promisor files we are repacking in 'builtin/repack.c' as suggested by a NEEDSWORK comment just above the code we are refactoring. Signed-off-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-17builtin/repack.c: don't move existing packs out of the wayLibravatar Taylor Blau1-89/+14
When 'git repack' creates a pack with the same name as any existing pack, it moves the existing one to 'old-pack-xxx.{pack,idx,...}' and then renames the new one into place. Eventually, it would be nice to have 'git repack' allow for writing a multi-pack index at the critical time (after the new packs have been written / moved into place, but before the old ones have been deleted). Guessing that this option might be called '--write-midx', this makes the following situation (where repacks are issued back-to-back without any new objects) impossible: $ git repack -adb $ git repack -adb --write-midx In the second repack, the existing packs are overwritten verbatim with the same rename-to-old sequence. At that point, the current MIDX is invalidated, since it refers to now-missing packs. So that code wants to be run after the MIDX is re-written. But (prior to this patch) the new MIDX can't be written until the new packs are moved into place. So, we have a circular dependency. This is all hypothetical, since no code currently exists to write a MIDX safely during a 'git repack' (the 'GIT_TEST_MULTI_PACK_INDEX' does so unsafely). Putting hypothetical aside, though: why do we need to rename existing packs to be prefixed with 'old-' anyway? This behavior dates all the way back to 2ad47d6 (git-repack: Be careful when updating the same pack as an existing one., 2006-06-25). 2ad47d6 is mainly concerned about a case where a newly written pack would have a different structure than its index. This used to be possible when the pack name was a hash of the set of objects. Under this naming scheme, two packs that store the same set of objects could differ in delta selection, object positioning, or both. If this happened, then any such packs would be unreadable in the instant between copying the new pack and new index (i.e., either the index or pack will be stale depending on the order that they were copied). But since 1190a1a (pack-objects: name pack files after trailer hash, 2013-12-05), this is no longer possible, since pack files are named not after their logical contents (i.e., the set of objects), but by the actual checksum of their contents. So, this old- behavior can safely go, which allows us to avoid our circular dependency above. In addition to avoiding the circular dependency, this patch also makes 'git repack' a lot simpler, since we don't have to deal with failures encountered when renaming existing packs to be prefixed with 'old-'. This patch is mostly limited to removing code paths that deal with the 'old' prefixing, with the exception of files that include the pack's name in their own filename, like .idx, .bitmap, and related files. The exception is that we want to continue to trust what pack-objects wrote. That is, it is not the case that we pretend as if pack-objects didn't write files identical to ones that already exist, but rather that we respect what pack-objects wrote as the source of truth. That cuts two ways: - If pack-objects produced an identical pack to one that already exists with a bitmap, but did not produce a bitmap, we remove the bitmap that already exists. (This behavior is codified in t7700.14). - If pack-objects produced an identical pack to one that already exists, we trust the just-written version of the coresponding .idx, .promisor, and other files over the ones that already exist. This ensures that we use the most up-to-date versions of this files, which is safe even in the face of format changes in, say, the .idx file (which would not be reflected in the .idx file's name). Helped-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-16builtin/repack.c: keep track of what pack-objects wroteLibravatar Taylor Blau1-1/+30
In the subsequent commit, it will become useful to keep track of which metadata files were written by pack-objects. We already do this to an extent with the 'exts' array, which only is used in the context of existing packs. Co-authored-by: Jeff King <peff@peff.net> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-16repack: make "exts" array available outside cmd_repack()Libravatar Jeff King1-9/+10
We'll use it in a helper function soon. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-09Merge branch 'tb/repack-clearing-midx'Libravatar Junio C Hamano1-7/+5
When a packfile is removed by "git repack", multi-pack-index gets cleared; the code was taught to do so less aggressively by first checking if the midx actually refers to a pack that no longer exists. * tb/repack-clearing-midx: midx: traverse the local MIDX first builtin/repack.c: invalidate MIDX only when necessary
2020-08-28midx: traverse the local MIDX firstLibravatar Taylor Blau1-1/+1
When a repository has an alternate object directory configured, callers can traverse through each alternate's MIDX by walking the '->next' pointer. But, when 'prepare_multi_pack_index_one()' loads multiple MIDXs, it places the new ones at the front of this pointer chain, not at the end. This can be confusing for callers such as 'git repack -ad', causing test failures like in t7700.6 with 'GIT_TEST_MULTI_PACK_INDEX=1'. The occurs when dropping a pack known to the local MIDX with alternates configured that have their own MIDX. Since the alternate's MIDX is returned via 'get_multi_pack_index()', 'midx_contains_pack()' returns true (which is correct, since it traverses through the '->next' pointer to find the MIDX in the chain that does contain the requested object). But, we call 'clear_midx_file()' on 'the_repository', which drops the MIDX at the path of the first MIDX in the chain, which (in the case of t7700.6 is the one in the alternate). This patch addresses that by: - placing the local MIDX first in the chain when calling 'prepare_multi_pack_index_one()', and - introducing a new 'get_local_multi_pack_index()', which explicitly returns the repository-local MIDX, if any. Don't impose an additional order on the MIDX's '->next' pointer beyond that the first item in the chain must be local if one exists so that we avoid a quadratic insertion. Likewise, use 'get_local_multi_pack_index()' in 'remove_redundant_pack()' to fix the formerly broken t7700.6 when run with 'GIT_TEST_MULTI_PACK_INDEX=1'. Finally, note that the MIDX ordering invariant is only preserved by the insertion order in 'prepare_packed_git()', which traverses through the ODB's '->next' pointer, meaning we visit the local object store first. This fragility makes this an undesirable long-term solution if more callers are added, but it is acceptable for now since this is the only caller. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-26builtin/repack.c: invalidate MIDX only when necessaryLibravatar Taylor Blau1-7/+5
In 525e18c04b (midx: clear midx on repack, 2018-07-12), 'git repack' learned to remove a multi-pack-index file if it added or removed a pack from the object store. This mechanism is a little over-eager, since it is only necessary to drop a MIDX if 'git repack' removes a pack that the MIDX references. Adding a pack outside of the MIDX does not require invalidating the MIDX, and likewise for removing a pack the MIDX does not know about. Teach 'git repack' to check for this by loading the MIDX, and checking whether the to-be-removed pack is known to the MIDX. This requires a slightly odd alternation to a test in t5319, which is explained with a comment. A new test is added to show that the MIDX is left alone when both packs known to it are marked as .keep, but two packs unknown to it are removed and combined into one new pack. Helped-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28strvec: fix indentation in renamed callsLibravatar Jeff King1-4/+4
Code which split an argv_array call across multiple lines, like: argv_array_pushl(&args, "one argument", "another argument", "and more", NULL); was recently mechanically renamed to use strvec, which results in mis-matched indentation like: strvec_pushl(&args, "one argument", "another argument", "and more", NULL); Let's fix these up to align the arguments with the opening paren. I did this manually by sifting through the results of: git jump grep 'strvec_.*,$' and liberally applying my editor's auto-format. Most of the changes are of the form shown above, though I also normalized a few that had originally used a single-tab indentation (rather than our usual style of aligning with the open paren). I also rewrapped a couple of obvious cases (e.g., where previously too-long lines became short enough to fit on one), but I wasn't aggressive about it. In cases broken to three or more lines, the grouping of arguments is sometimes meaningful, and it wasn't worth my time or reviewer time to ponder each case individually. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28strvec: convert builtin/ callers away from argv_array nameLibravatar Jeff King1-31/+31
We eventually want to drop the argv_array name and just use strvec consistently. There's no particular reason we have to do it all at once, or care about interactions between converted and unconverted bits. Because of our preprocessor compat layer, the names are interchangeable to the compiler (so even a definition and declaration using different names is OK). This patch converts all of the files in builtin/ to keep the diff to a manageable size. The conversion was done purely mechanically with: git ls-files '*.c' '*.h' | xargs perl -i -pe ' s/ARGV_ARRAY/STRVEC/g; s/argv_array/strvec/g; ' and then selectively staging files with "git add builtin/". We'll deal with any indentation/style fallouts separately. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28strvec: rename files from argv-array to strvecLibravatar Jeff King1-1/+1
This requires updating #include lines across the code-base, but that's all fairly mechanical, and was done with: git ls-files '*.c' '*.h' | xargs perl -i -pe 's/argv-array.h/strvec.h/' Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-13Merge branch 'tb/shallow-cleanup'Libravatar Junio C Hamano1-0/+1
Code cleanup. * tb/shallow-cleanup: shallow: use struct 'shallow_lock' for additional safety shallow.h: document '{commit,rollback}_shallow_file' shallow: extract a header file for shallow-related functions commit: make 'commit_graft_pos' non-static
2020-04-30shallow: extract a header file for shallow-related functionsLibravatar Taylor Blau1-0/+1
There are many functions in commit.h that are more related to shallow repositories than they are to any sort of generic commit machinery. Likely this began when there were only a few shallow-related functions, and commit.h seemed a reasonable enough place to put them. But, now there are a good number of shallow-related functions, and placing them all in 'commit.h' doesn't make sense. This patch extracts a 'shallow.h', which takes all of the declarations from 'commit.h' for functions which already exist in 'shallow.c'. We will bring the remaining shallow-related functions defined in 'commit.c' in a subsequent patch. For now, move only the ones that already are implemented in 'shallow.c', and update the necessary includes. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-24Lib-ify prune-packedLibravatar Denton Liu1-0/+1
In builtin.h, there exists the distinctly lib-ish function prune_packed_objects(). This function can currently only be called by built-in commands but, unlike all of the other functions in the header, it does not make sense to impose this restriction as the functionality can be logically reused in libgit. Extract this function into prune-packed.c so that related definitions can exist clearly in their own header file. While we're at it, clean up #includes that are unused. This patch is best viewed with --color-moved. Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-10Merge branch 'wb/midx-progress'Libravatar Junio C Hamano1-1/+1
The code to generate multi-pack index learned to show (or not to show) progress indicators. * wb/midx-progress: multi-pack-index: add [--[no-]progress] option. midx: honor the MIDX_PROGRESS flag in midx_repack midx: honor the MIDX_PROGRESS flag in verify_midx_file midx: add progress to expire_midx_packs midx: add progress to write_midx_file midx: add MIDX_PROGRESS flag
2019-10-23midx: add MIDX_PROGRESS flagLibravatar William Baker1-1/+1
Add the MIDX_PROGRESS flag and update the write|verify|expire|repack functions in midx.h to accept a flags parameter. The MIDX_PROGRESS flag indicates whether the caller of the function would like progress information to be displayed. This patch only changes the method prototypes and does not change the functionality. The functionality change will be handled by a later patch. Signed-off-by: William Baker <William.Baker@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-16fetch-pack: write fetched refs to .promisorLibravatar Jonathan Tan1-0/+7
The specification of promisor packfiles (in partial-clone.txt) states that the .promisor files that accompany packfiles do not matter (just like .keep files), so whenever a packfile is fetched from the promisor remote, Git has been writing empty .promisor files. But these files could contain more useful information. So instead of writing empty files, write the refs fetched to these files. This makes it easier to debug issues with partial clones, as we can identify what refs (and their associated hashes) were fetched at the time the packfile was downloaded, and if necessary, compare those hashes against what the promisor remote reports now. This is implemented by teaching fetch-pack to write its own non-empty .promisor file whenever it knows the name of the pack's lockfile. This covers the case wherein the user runs "git fetch" with an internal protocol or HTTP protocol v2 (fetch_refs_via_pack() in transport.c sets lock_pack) and with HTTP protocol v0/v1 (fetch_git() in remote-curl.c passes "--lock-pack" to "fetch-pack"). Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Acked-by: Josh Steadmon <steadmon@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-11Merge branch 'bc/object-id-part17'Libravatar Junio C Hamano1-1/+1
Preparation for SHA-256 upgrade continues. * bc/object-id-part17: (26 commits) midx: switch to using the_hash_algo builtin/show-index: replace sha1_to_hex rerere: replace sha1_to_hex builtin/receive-pack: replace sha1_to_hex builtin/index-pack: replace sha1_to_hex packfile: replace sha1_to_hex wt-status: convert struct wt_status to object_id cache: remove null_sha1 builtin/worktree: switch null_sha1 to null_oid builtin/repack: write object IDs of the proper length pack-write: use hash_to_hex when writing checksums sequencer: convert to use the_hash_algo bisect: switch to using the_hash_algo sha1-lookup: switch hard-coded constants to the_hash_algo config: use the_hash_algo in abbrev comparison combine-diff: replace GIT_SHA1_HEXSZ with the_hash_algo bundle: switch to use the_hash_algo connected: switch GIT_SHA1_HEXSZ to the_hash_algo show-index: switch hard-coded constants to the_hash_algo blame: remove needless comparison with GIT_SHA1_HEXSZ ...
2019-09-18Merge branch 'cc/multi-promisor'Libravatar Junio C Hamano1-1/+2
Teach the lazy clone machinery that there can be more than one promisor remote and consult them in order when downloading missing objects on demand. * cc/multi-promisor: Move core_partial_clone_filter_default to promisor-remote.c Move repository_format_partial_clone to promisor-remote.c Remove fetch-object.{c,h} in favor of promisor-remote.{c,h} remote: add promisor and partial clone config to the doc partial-clone: add multiple remotes in the doc t0410: test fetching from many promisor remotes builtin/fetch: remove unique promisor remote limitation promisor-remote: parse remote.*.partialclonefilter Use promisor_remote_get_direct() and has_promisor_remote() promisor-remote: use repository_format_partial_clone promisor-remote: add promisor_remote_reinit() promisor-remote: implement promisor_remote_get_direct() Add initial support for many promisor remotes fetch-object: make functions return an error code t0410: remove pipes after git commands
2019-08-19builtin/repack: write object IDs of the proper lengthLibravatar brian m. carlson1-1/+1
Use the_hash_algo when calling xwrite with a hex object ID so that the proper amount of data is written. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-07-31repack: simplify handling of auto-bitmaps and .keep filesLibravatar Jeff King1-15/+2
Commit 7328482253 (repack: disable bitmaps-by-default if .keep files exist, 2019-06-29) taught repack to prefer disabling bitmaps to duplicating objects (unless bitmaps were asked for explicitly). But there's an easier way to do this: if we keep passing the --honor-pack-keep flag to pack-objects when auto-enabling bitmaps, then pack-objects already makes the same decision (it will disable bitmaps rather than duplicate). Better still, pack-objects can actually decide to do so based not just on the presence of a .keep file, but on whether that .keep file actually impacts the new pack we're making (so if we're racing with a push or fetch, for example, their temporary .keep file will not block us from generating bitmaps if they haven't yet updated their refs). And because repack uses the --write-bitmap-index-quiet flag, we don't have to worry about pack-objects generating confusing warnings when it does see a .keep file. We can confirm this by tweaking the .keep test to check repack's stderr. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-07-31repack: silence warnings when auto-enabled bitmaps cannot be builtLibravatar Jeff King1-6/+9
Depending on various config options, a full repack may not be able to build a reachability bitmap index (e.g., if pack.packSizeLimit forces us to write multiple packs). In these cases pack-objects may write a warning to stderr. Since 36eba0323d (repack: enable bitmaps by default on bare repos, 2019-03-14), we may generate these warnings even when the user did not explicitly ask for bitmaps. This has two downsides: - it can be confusing, if they don't know what bitmaps are - a daemonized auto-gc will write this to its log file, and the presence of the warning may suppress further auto-gc (until gc.logExpiry has elapsed) Let's have repack communicate to pack-objects that the choice to turn on bitmaps was not made explicitly by the user, which in turn allows pack-objects to suppress these warnings. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-07-19Merge branch 'ew/repack-with-bitmaps-by-default'Libravatar Junio C Hamano1-2/+16
Generation of pack bitmaps are now disabled when .keep files exist, as these are mutually exclusive features. * ew/repack-with-bitmaps-by-default: repack: disable bitmaps-by-default if .keep files exist
2019-07-19Merge branch 'ds/midx-expire-repack'Libravatar Junio C Hamano1-12/+2
"git multi-pack-index" learned expire and repack subcommands. * ds/midx-expire-repack: t5319: use 'test-tool path-utils' instead of 'ls -l' t5319-multi-pack-index.sh: test batch size zero midx: add test that 'expire' respects .keep files multi-pack-index: test expire while adding packs midx: implement midx_repack() multi-pack-index: prepare 'repack' subcommand multi-pack-index: implement 'expire' subcommand midx: refactor permutation logic and pack sorting midx: simplify computation of pack name lengths multi-pack-index: prepare for 'expire' subcommand Docs: rearrange subcommands for multi-pack-index repack: refactor pack deletion for future use
2019-07-09Merge branch 'ds/close-object-store'Libravatar Junio C Hamano1-1/+1
The commit-graph file is now part of the "files that the runtime may keep open file descriptors on, all of which would need to be closed when done with the object store", and the file descriptor to an existing commit-graph file now is closed before "gc" finalizes a new instance to replace it. * ds/close-object-store: packfile: rename close_all_packs to close_object_store packfile: close commit-graph in close_all_packs commit-graph: use raw_object_store when closing
2019-07-01repack: disable bitmaps-by-default if .keep files existLibravatar Eric Wong1-2/+16
Bitmaps aren't useful with multiple packs, and users with .keep files ended up with redundant packs when bitmaps got enabled by default in bare repos. So detect when .keep files exist and stop enabling bitmaps by default in that case. Wasteful (but otherwise harmless) race conditions with .keep files documented by Jeff King still apply and there's a chance we'd still end up with redundant data on the FS: https://public-inbox.org/git/20190623224244.GB1100@sigill.intra.peff.net/ v2: avoid subshell in test case, be multi-index aware Fixes: 36eba0323d3288a8 ("repack: enable bitmaps by default on bare repos") Signed-off-by: Eric Wong <e@80x24.org> Helped-by: Jeff King <peff@peff.net> Reported-by: Janos Farkas <chexum@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-25Use promisor_remote_get_direct() and has_promisor_remote()Libravatar Christian Couder1-1/+2
Instead of using the repository_format_partial_clone global and fetch_objects() directly, let's use has_promisor_remote() and promisor_remote_get_direct(). This way all the configured promisor remotes will be taken into account, not only the one specified by extensions.partialClone. Also when cloning or fetching using a partial clone filter, remote.origin.promisor will be set to "true" instead of setting extensions.partialClone to "origin". This makes it possible to use many promisor remote just by fetching from them. Signed-off-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-12packfile: rename close_all_packs to close_object_storeLibravatar Derrick Stolee1-1/+1
The close_all_packs() method is now responsible for more than just pack-files. It also closes the commit-graph and the multi-pack-index. Rename the function to be more descriptive of its larger role. The name also fits because the input parameter is a raw_object_store. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-11repack: refactor pack deletion for future useLibravatar Derrick Stolee1-12/+2
The repack builtin deletes redundant pack-files and their associated .idx, .promisor, .bitmap, and .keep files. We will want to re-use this logic in the future for other types of repack, so pull the logic into 'unlink_pack_path()' in packfile.c. The 'ignore_keep' parameter is enabled for the use in repack, but will be important for a future caller. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-18repack: enable bitmaps by default on bare reposLibravatar Eric Wong1-1/+4
A typical use case for bare repos is for serving clones and fetches to clients. Enable bitmaps by default on bare repos to make it easier for admins to host git repos in a performant way. Signed-off-by: Eric Wong <e@80x24.org> Helped-by: Jeff King <peff@peff.net> Acked-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-18Merge branch 'js/gc-repack-close-before-remove'Libravatar Junio C Hamano1-0/+2
"git gc" and "git repack" did not close the open packfiles that they found unneeded before removing them, which didn't work on a platform incapable of removing an open file. This has been corrected. * js/gc-repack-close-before-remove: gc/repack: release packs when needed
2019-01-11gc/repack: release packs when neededLibravatar Johannes Schindelin1-0/+2
On Windows, files cannot be removed nor renamed if there are still handles held by a process. To remedy that, we introduced the close_all_packs() function. Earlier, we made sure that the packs are released just before `git gc` is spawned, in case that gc wants to remove no-longer needed packs. But this developer forgot that gc itself also needs to let go of packs, e.g. when consolidating all packs via the --aggressive option. Likewise, `git repack -d` wants to delete obsolete packs and therefore needs to close all pack handles, too. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-04Merge branch 'nd/i18n'Libravatar Junio C Hamano1-13/+13
More _("i18n") markings. * nd/i18n: fsck: mark strings for translation fsck: reduce word legos to help i18n parse-options.c: mark more strings for translation parse-options.c: turn some die() to BUG() parse-options: replace opterror() with optname() repack: mark more strings for translation remote.c: mark messages for translation remote.c: turn some error() or die() to BUG() reflog: mark strings for translation read-cache.c: add missing colon separators read-cache.c: mark more strings for translation read-cache.c: turn die("internal error") to BUG() attr.c: mark more string for translation archive.c: mark more strings for translation alias.c: mark split_cmdline_strerror() strings for translation git.c: mark more strings for translation
2018-11-13Merge branch 'ds/test-multi-pack-index'Libravatar Junio C Hamano1-2/+5
Tests for the recently introduced multi-pack index machinery. * ds/test-multi-pack-index: packfile: close multi-pack-index in close_all_packs multi-pack-index: define GIT_TEST_MULTI_PACK_INDEX midx: close multi-pack-index on repack midx: fix broken free() in close_midx()
2018-11-12repack: mark more strings for translationLibravatar Nguyễn Thái Ngọc Duy1-13/+13
Two strings are slightly updated to be consistent with the rest: die() starts with lowercase. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-06Merge branch 'js/shallow-and-fetch-prune'Libravatar Junio C Hamano1-0/+6
"git repack" in a shallow clone did not correctly update the shallow points in the repository, leading to a repository that does not pass fsck. * js/shallow-and-fetch-prune: repack -ad: prune the list of shallow commits shallow: offer to prune only non-existing entries repack: point out a bug handling stale shallow info
2018-10-25repack -ad: prune the list of shallow commitsLibravatar Johannes Schindelin1-0/+6
`git repack` can drop unreachable commits without further warning, making the corresponding entries in `.git/shallow` invalid, which causes serious problems when deepening the branches. One scenario where unreachable commits are dropped by `git repack` is when a `git fetch --prune` (or even a `git fetch` when a ref was force-pushed in the meantime) can make a commit unreachable that was reachable before. Therefore it is not safe to assume that a `git repack -adlf` will keep unreachable commits alone (under the assumption that they had not been packed in the first place, which is an assumption at least some of Git's code seems to make). This is particularly important to keep in mind when looking at the `.git/shallow` file: if any commits listed in that file become unreachable, it is not a problem, but if they go missing, it *is* a problem. One symptom of this problem is that a deepening fetch may now fail with fatal: error in object: unshallow <commit-hash> To avoid this problem, let's prune the shallow list in `git repack` when the `-d` option is passed, unless `-A` is passed, too (which would force the now-unreachable objects to be turned into loose objects instead of being deleted). Additionally, we also need to take `--keep-reachable` and `--unpack-unreachable=<date>` into account. Note: an alternative solution discussed during the review of this patch was to teach `git fetch` to simply ignore entries in .git/shallow if the corresponding commits do not exist locally. A quick test, however, revealed that the .git/shallow file is written during a shallow *clone*, in which case the commits do not exist, either, but the "shallow" line *does* need to be sent. Therefore, this approach would be a lot more finicky than the approach presented by the this patch. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-10-22multi-pack-index: define GIT_TEST_MULTI_PACK_INDEXLibravatar Derrick Stolee1-0/+4
The multi-pack-index feature is tested in isolation by t5319-multi-pack-index.sh, but there are many more interesting scenarios in the test suite surrounding pack-file data shapes and interactions. Since the multi-pack-index is an optional data structure, it does not make sense to include it by default in those tests. Instead, add a new GIT_TEST_MULTI_PACK_INDEX environment variable that enables core.multiPackIndex and writes a multi-pack-index after each 'git repack' command. This adds extra test coverage when needed. There are a few spots in the test suite that need to react to this change: * t5319-multi-pack-index.sh: there is a test that checks that 'git repack' deletes the multi-pack-index. Disable the environment variable to ensure this still happens. * t5310-pack-bitmaps.sh: One test moves a pack-file from the object directory to an alternate. This breaks the multi-pack-index, so delete the multi-pack-index at this point, if it exists. * t9300-fast-import.sh: One test verifies the number of files in the .git/objects/pack directory is exactly 8. Exclude the multi-pack-index from this count so it is still 8 in all cases. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-10-22midx: close multi-pack-index on repackLibravatar Derrick Stolee1-2/+1
When repacking, we may remove pack-files. This invalidates the multi-pack-index (if it exists). Previously, we removed the multi-pack-index file before removing any pack-file. In some cases, the repack command may load the multi-pack-index into memory. This may lead to later in-memory references to the non-existent pack- files. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-10-15builtin/repack: replace hard-coded constantsLibravatar brian m. carlson1-6/+7
Note that while the error messages here are not translated, the end user should never see them. We invoke git pack-objects shortly before both invocations, so we can be fairly certain that the data we're receiving is in fact valid. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-17Merge branch 'cc/delta-islands'Libravatar Junio C Hamano1-0/+9
Lift code from GitHub to restrict delta computation so that an object that exists in one fork is not made into a delta against another object that does not appear in the same forked repository. * cc/delta-islands: pack-objects: move 'layer' into 'struct packing_data' pack-objects: move tree_depth into 'struct packing_data' t5320: tests for delta islands repack: add delta-islands support pack-objects: add delta-islands support pack-objects: refactor code into compute_layer_order() Add delta-islands.{c,h}
2018-08-20Sync 'ds/multi-pack-index' to v2.19.0-rc0Libravatar Junio C Hamano1-0/+9
* ds/multi-pack-index: (23 commits) midx: clear midx on repack packfile: skip loading index if in multi-pack-index midx: prevent duplicate packfile loads midx: use midx in approximate_object_count midx: use existing midx when writing new one midx: use midx in abbreviation calculations midx: read objects from multi-pack-index config: create core.multiPackIndex setting midx: write object offsets midx: write object id fanout chunk midx: write object ids in a chunk midx: sort and deduplicate objects from packfiles midx: read pack names into array multi-pack-index: write pack names in chunk multi-pack-index: read packfile list packfile: generalize pack directory list t5319: expand test data multi-pack-index: load into memory midx: write header information to lockfile multi-pack-index: add 'write' verb ...