Our current scheme for naming packfiles is to calculate the
sha1 hash of the sorted list of objects contained in the
packfile. This gives us a unique name, so we are reasonably
sure that two packs with the same name will contain the same
objects.
It does not, however, tell us that two such packs have the
exact same bytes. This makes things awkward if we repack the
same set of objects. Due to run-to-run variations, the bytes
may not be identical (e.g., changed zlib or git versions,
different source object reuse due to new packs in the
repository, or even different deltas due to races during a
multi-threaded delta search).
In theory, this could be helpful to a program that cares
that the packfile contains a certain set of objects, but
does not care about the particular representation. In
practice, no part of git makes use of that, and in many
cases it is potentially harmful. For example, if a dumb http
client fetches the .idx file, it must be sure to get the
exact .pack that matches it. Similarly, a partial transfer
of a .pack file cannot be safely resumed, as the actual
bytes may have changed. This could also affect a local
client which opened the .idx and .pack files, closes the
.pack file (due to memory or file descriptor limits), and
then re-opens a changed packfile.
In all of these cases, git can detect the problem, as we
have the sha1 of the bytes themselves in the pack trailer
(which we verify on transfer), and the .idx file references
the trailer from the matching packfile. But it would be
simpler and more efficient to actually get the correct
bytes, rather than noticing the problem and having to
restart the operation.
This patch simply uses the pack trailer sha1 as the pack
name. It should be similarly unique, but covers the exact
representation of the objects. Other parts of git should not
care, as the pack name is returned by pack-objects and is
essentially opaque.
One test needs to be updated, because it actually corrupts a
pack and expects that re-packing the corrupted bytes will
use the same name. It won't anymore, but we can easily just
use the name that pack-objects hands back.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* jc/stream-to-pack:
bulk-checkin: replace fast-import based implementation
csum-file: introduce sha1file_checkpoint
finish_tmp_packfile(): a helper function
create_tmp_packfile(): a helper function
write_pack_header(): a helper function
Conflicts:
pack.h
When receive-pack & fetch-pack are run and store the pack obtained over
the wire to a local repository, they internally run the index-pack command
with the --strict option. Make sure that we reject incoming packfile that
records objects twice to avoid spreading such a damage.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
fsck is usually a long process and it would be nice if it prints
progress from time to time.
Progress meter is not printed when --verbose is given because
--verbose prints a lot, there's no need for "alive" indicator.
Progress meter may provide "% complete" information but it would
be lost anyway in the flood of text.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
During verify_pack() all objects are read for SHA-1 check. Then
fsck_sha1() is called on every object, which read the object again
(fsck_sha1 -> parse_object -> read_sha1_file).
Avoid reading an object twice, do fsck_sha1 while we have an object
uncompressed data in verify_pack.
On git.git, with this patch I got:
$ /usr/bin/time ./git fsck >/dev/null
98.97user 0.90system 1:40.01elapsed 99%CPU (0avgtext+0avgdata 616624maxresident)k
0inputs+0outputs (0major+194186minor)pagefaults 0swaps
Without it:
$ /usr/bin/time ./git fsck >/dev/null
231.23user 2.35system 3:53.82elapsed 99%CPU (0avgtext+0avgdata 636688maxresident)k
0inputs+0outputs (0major+461629minor)pagefaults 0swaps
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Factor out a small logic out of the private write_pack_file() function
in builtin/pack-objects.c.
This changes the order of finishing multi-pack generation slightly. The
code used to
- adjust shared perm of temporary packfile
- rename temporary packfile to the final name
- update mtime of the packfile under the final name
- adjust shared perm of temporary idxfile
- rename temporary idxfile to the final name
but because the helper does not want to do the mtime thing, the updated
code does that step first and then all the rest.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A pack v2 .idx file usually records offset using 64-bit representation
only when the offset does not fit within 31-bit, but you can handcraft
your .idx file to record smaller offset using 64-bit, storing all zero
in the upper 4-byte. By inspecting the original idx file when running
index-pack --verify, encode such low offsets that do not need to be in
64-bit but are encoded using 64-bit just like the original idx file so
that we can still validate the pack/idx pair by comparing the idx file
recomputed with the original.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Given an existing .pack file and the .idx file that describes it,
this new mode of operation reads and re-index the packfile and makes
sure the existing .idx file matches the result byte-for-byte.
All the objects in the .pack file are validated during this operation as
well. Unlike verify-pack, which visits each object described in the .idx
file in the SHA-1 order, index-pack efficiently exploits the delta-chain
to avoid rebuilding the objects that are used as the base of deltified
objects over and over again while validating the objects, resulting in
much quicker verification of the .pack file and its .idx file.
This version however cannot verify a .pack/.idx pair with a handcrafted v2
index that uses 64-bit offset representation for offsets that would fit
within 31-bit. You can create such an .idx file by giving a custom offset
to --index-version option to the command.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Remove two globals, pack_idx_default version and pack_idx_off32_limit,
and place them in a pack_idx_option structure. Allow callers to pass
it to write_idx_file() as a parameter.
Adjust all callers to the API change.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* sp/maint-dumb-http-pack-reidx:
http.c::new_http_pack_request: do away with the temp variable filename
http-fetch: Use temporary files for pack-*.idx until verified
http-fetch: Use index-pack rather than verify-pack to check packs
Allow parse_pack_index on temporary files
Extract verify_pack_index for reuse from verify_pack
Introduce close_pack_index to permit replacement
http.c: Remove unnecessary strdup of sha1_to_hex result
http.c: Don't store destination name in request structures
http.c: Drop useless != NULL test in finish_http_pack_request
http.c: Tiny refactoring of finish_http_pack_request
t5550-http-fetch: Use subshell for repository operations
http.c: Remove bad free of static block
The dumb HTTP transport should verify an index is completely valid
before trying to use it. That requires checking the header/footer
but also checking the complete content SHA-1. All of this logic is
already in the front half of verify_pack, so pull it out into a new
function that can be reused.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit 1b22b6c897 made duplicated versions of encode_header() into a
common version called encode_in_pack_object_header(). There is however
a better location that sha1_file.c for such a function though, as
sha1_file.c contains nothing related to the creation of packs, and
it is quite populated already.
Also the comment that was moved to the header file should really remain
near the function as it covers implementation details and provides no
information about the actual function interface.
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This required some fairly trivial packfile function 'const' cleanup,
since the builtin commands get a const char *argv[] array.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Currently, this function has the potential to read corrupted pack data
from disk and give it a valid SHA1 checksum. Let's add the ability to
validate SHA1 checksum of existing data along the way, including before
and after any arbitrary point in the pack.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To do so, check_pack_crc() moved from builtin-pack-objects.c to
pack-check.c where it is more logical to share.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is called when verify_pack() has its verbose argument set, and
verbose in this context makes sense only for the actual 'git verify-pack'
command. Therefore let's move show_pack_info() to builtin-verify-pack.c
instead and remove useless verbose argument from verify_pack().
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* np/progress:
Show total transferred as part of throughput progress
make sure throughput display gets updated even if progress doesn't move
return the prune-packed progress display to the inner loop
add throughput display to git-push
add some copyright notice to the progress display code
add throughput display to index-pack
add throughput to progress display
relax usage of the progress API
make struct progress an opaque type
prune-packed: don't call display_progress() for every file
Stop displaying "Pack pack-$ID created." during git-gc
Teach prune-packed to use the standard progress meter
Change 'Deltifying objects' to 'Compressing objects'
fix for more minor memory leaks
fix const issues with some functions
pack-objects.c: fix some global variable abuse and memory leaks
pack-objects: no delta possible with only one object in the list
cope with multiple line breaks within sideband progress messages
more compact progress display
Two functions, namely write_idx_file() and open_pack_file(), currently
return a const pointer. However that pointer is either a copy of the
first argument, or set to a malloc'd buffer when that first argument
is null. In the later case it is wrong to qualify that pointer as const
since ownership of the buffer is transferred to the caller to dispose of,
and obviously the free() function is not meant to be passed const
pointers.
Making the return pointer not const causes a warning when the first
argument is returned since that argument is also marked const.
The correct thing to do is therefore to remove the const qualifiers,
avoiding the need for ugly casts only to silence some warnings.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
There is a subtle (but important) linkage between receive-pack and
index-pack that allows index-pack to create a packfile but protect
it from being deleted by a concurrent `git repack -a -d` operation.
The linkage works by having index-pack mark the newly created pack
with a ".keep" file and then it passes the SHA-1 name of that new
packfile to receive-pack along its stdout channel.
The receive-pack process must unkeep the packfile by deleting the
.keep file, but can it can only do so after all elgible refs have
been updated in the receiving repository. This ensures that the
packfile is either kept or its objects are reachable, preventing
a concurrent repacker from deleting the packfile before it can
determine that its objects are actually needed by the repository.
The new builtin-fetch code needs to perform the same actions if
it choose to run index-pack rather than unpack-objects, so I am
moving this code out to its own function where both receive-pack
and fetch-pack are able to invoke it when necessary. The caller
is responsible for deleting the returned ".keep" and freeing the
path if the returned path is not NULL.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This patch unifies the write_index_file functions in
builtin-pack-objects.c and index-pack.c. As the name
"index" is overloaded in git, move in the direction of
using "idx" and "pack idx" when refering to the pack index.
There should be no change in functionality.
Signed-off-by: Geert Bosch <bosch@gnat.com>
Acked-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Include a generalized fixup_pack_header_footer() in this new file.
Needed by git-repack --max-pack-size feature in a later patchset.
[sp: Moved close(pack_fd) to callers, to support index-pack, and
changed name to better indicate it is for packfiles.]
Signed-off-by: Dana L. How <danahow@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Especially with the new index format to come, it is more appropriate
to encapsulate more into check_packed_git_idx() and assume less of the
index format in struct packed_git.
To that effect, the index_base is renamed to index_data with void * type
so it is not used directly but other pointers initialized with it. This
allows for a couple pointer cast removal, as well as providing a better
generic name to grep for when adding support for new index versions or
formats.
And index_data is declared const too while at it.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Plain integer types without a fixed size can vary between platforms. Even
though all common platforms use 32-bit ints, there is no guarantee that
this won't change at some point. Furthermore, specifying an integer type
with explicit size makes the definition of structures more obvious.
Signed-off-by: Simon 'corecode' Schubert <corecode@fs.ei.tum.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Way back when Junio developed the 64 bit index topic he came up
with a means of changing the .idx file format so that older Git
clients would recognize that they don't understand the file and
refuse to read it, while newer clients could tell the difference
between the old-style and new-style .idx files. Unfortunately
this wasn't recorded anywhere.
This change documents how we might go about changing the .idx
file format by using a special signature in the first four bytes.
Credit (and possible blame) goes completely to Junio for thinking
up this technique.
The change also modifies the error message of the current Git code
so that users get a recommendation to upgrade their Git software
should this version or later encounter a new-style .idx which it
cannot process. We already do this for the .pack files, but since
we usually process the .idx files first its important that these
files are recognized and encourage an upgrade.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
* np/pack:
add the capability for index-pack to read from a stream
index-pack: compare only the first 20-bytes of the key.
git-repack: repo.usedeltabaseoffset
pack-objects: document --delta-base-offset option
allow delta data reuse even if base object is a preferred base
zap a debug remnant
let the GIT native protocol use offsets to delta base when possible
make pack data reuse compatible with both delta types
make git-pack-objects able to create deltas with offset to base
teach git-index-pack about deltas with offset to base
teach git-unpack-objects about deltas with offset to base
introduce delta objects with offset to base
This reverts commit 16854571aa.
Git as recent as v1.1.6 do not understand version 3 delta.
v1.2.0 is Ok and I personally would say it is old enough, but
the improvement between version 2 and version 3 delta is not
bit enough to justify breaking older clients.
We should resurrect this later, but when we do so we shold
make it conditional.
Signed-off-by: Junio C Hamano <junkio@cox.net>
This is the missing part to git-pack-objects allowing it to reuse delta
data to/from any of the two delta types. It can reuse delta from any
type, and it outputs base offsets when --allow-delta-base-offset is
provided and the base is also included in the pack. Otherwise it
outputs base sha1 references just like it always did.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
It's been quite a while now that GIT is able to read version 3 packs.
Let's create them at last.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This updates the type-enumeration constants introduced to reduce
the memory footprint of "struct object" to match the type bits
already used in the packfile format, by removing the former
(i.e. TYPE_* constant macros) and using the latter (i.e. enum
object_type) throughout the code for consistency.
Eventually we can stop passing around the "type strings"
entirely, and this will help - no confusion about two different
integer enumeration.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
When generating a new pack, notice if we have already needed
objects in existing packs. If an object is stored deltified,
and its base object is also what we are going to pack, then
reuse the existing deltified representation unconditionally,
bypassing all the expensive find_deltas() and try_deltas()
calls.
Also, notice if what we are going to write out exactly match
what is already in an existing pack (either deltified or just
compressed). In such a case, we can just copy it instead of
going through the usual uncompressing & recompressing cycle.
Without this patch, in linux-2.6 repository with about 1500
loose objects and a single mega pack:
$ git-rev-list --objects v2.6.16-rc3 >RL
$ wc -l RL
184141 RL
$ time git-pack-objects p <RL
Generating pack...
Done counting 184141 objects.
Packing 184141 objects....................
a1fc7b3e537fcb9b3c46b7505df859f0a11e79d2
real 12m4.323s
user 11m2.560s
sys 0m55.950s
With this patch, the same input:
$ time ../git.junio/git-pack-objects q <RL
Generating pack...
Done counting 184141 objects.
Packing 184141 objects.....................
a1fc7b3e537fcb9b3c46b7505df859f0a11e79d2
Total 184141, written 184141, reused 182441
real 1m2.608s
user 0m55.090s
sys 0m1.830s
Signed-off-by: Junio C Hamano <junkio@cox.net>
After experimenting with code to add the ability to encode a delta
against part of the deltified file, it turns out that resulting packs
are _bigger_ than when this ability is not used. The raw delta output
might be smaller, but it doesn't compress as well using gzip with a
negative net saving on average.
Said bit would in fact be more useful to allow for encoding the copying
of chunks larger than 64KB providing more savings with large files.
This will correspond to packs version 3.
While the current code still produces packs version 2, it is made future
proof so pack versions 2 and 3 are accepted. Any pack version 2 are
compatible with version 3 since the redefined bit was never used before.
When enough time has passed, code to use that bit to produce version 3
packs could be added.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Nico pointed out that having verify_pack.c and verify-pack.c was
confusing. Rename verify_pack.c to pack-check.c as suggested,
and enhances the verification done quite a bit.
- Built-in sha1_file unpacking knows that a base object of a
deltified object _must_ be in the same pack, and takes
advantage of that fact.
- Earlier verify-pack command only checked the SHA1 sum for the
entire pack file and did not look into its contents. It now
checks everything idx file claims to have unpacks correctly.
- It now has a hook to give more detailed information for
objects contained in the pack under -v flag.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Given a list of <pack>.idx files, this command validates the
index file and the corresponding .pack file for consistency.
This patch also uses the same validation mechanism in fsck-cache
when the --full flag is used.
During normal operation, sha1_file.c verifies that a given .idx
file matches the .pack file by comparing the SHA1 checksum
stored in .idx file and .pack file as a minimum sanity check.
We may further want to check the pack signature and version when
we map the pack, but that would be a separate patch.
Earlier, errors to map a pack file was not flagged fatal but led
to a random fatal error later. This version explicitly die()s
when such an error is detected.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This makes it match the new delta encoding, and admittedly makes the
code easier to follow.
This also updates the PACK file version to 2, since this (and the delta
encoding change in the previous commit) are incompatible with the old
format.
This also adds a header with a signature, version info, and the number
of objects to the pack file. It also encodes the file length and type
more efficiently.
Jeff King
Junio C Hamano
Nguyễn Thái Ngọc Duy
Shawn O. Pearce
Nicolas Pitre
Linus Torvalds
Nicolas Pitre
Geert Bosch
Dana L. How
Junio C Hamano
Simon 'corecode' Schubert
Linus Torvalds
Linus Torvalds