This means that we can depend on packs always being stable on disk,
simplifying a lot of the object serialization worries. And unlike loose
objects, serializing pack creation IO isn't going to be a performance
killer.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
xread() and xwrite() return ssize_t values as their native POSIX
counterparts read(2) and write(2).
To be consistent, read_in_full() and write_in_full() should also return
ssize_t values.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This patch arose from a discussion started by Jim Meyering's patch
whose intention was to provide better diagnostics for failed writes.
Linus proposed a better way to do things, which also had the added
benefit that adding a fflush() to git-log-* operations and incremental
git-blame operations could improve interactive respose time feel, at
the cost of making things a bit slower when we aren't piping the
output to a downstream program.
This patch skips the fflush() calls when stdout is a regular file, or
if the environment variable GIT_FLUSH is set to "0". This latter can
speed up a command such as:
GIT_FLUSH=0 strace -c -f -e write time git-rev-list HEAD | wc -l
a tiny amount.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It received the return value from xwrite() in a size_t variable
'written' and expected comparison with 0 would catch an error
from xwrite().
Signed-off-by: Junio C Hamano <junkio@cox.net>
Originally I introduced read_or_die for the purpose of reading
the pack header and trailer, and I was too lazy to print proper
error messages.
Linus Torvalds <torvalds@osdl.org>:
> For a read error, at the very least you have to say WHICH FILE
> couldn't be read, because it's usually a matter of some file just
> being too short, not some system-wide problem.
and of course Linus is right. Make it so.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
The "read_or_die()" function would silently NOT die for a partial read,
and since it was of type "void" it obviously couldn't even return the
partial number of bytes read.
IOW, it was totally broken. This hopefully fixes it up.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
With the new-and-improved write_in_full() semantics, where a partial write
simply always returns a real error (and always sets 'errno' when that
happens, including for the disk full case), a lot of the callers of
write_in_full() were just unnecessarily complex.
In particular, there's no reason to ever check for a zero length or
return: if the length was zero, we'll return zero, otherwise, if a disk
full resulted in the actual write() system call returning zero the
write_in_full() logic would have correctly turned that into a negative
return value, with 'errno' set to ENOSPC.
I really wish every "write_in_full()" user would just check against "<0"
now, but this fixes the nasty and stupid ones.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Unfortunately, while {read,write}_in_full do take into account
zero-sized reads/writes; their die and whine variants do not.
I have a repository where there are zero-sized files in
the history that was triggering these things.
Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>
We have a number of badly checked write() calls. Often we are
expecting write() to write exactly the size we requested or fail,
this fails to handle interrupts or short writes. Switch to using
the new write_in_full(). Otherwise we at a minimum need to check
for EINTR and EAGAIN, where this is appropriate use xwrite().
Note, the changes to config handling are much larger and handled
in the next patch in the sequence.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
We have a number of badly checked read() calls. Often we are
expecting read() to read exactly the size we requested or fail, this
fails to handle interrupts or short reads. Add a read_in_full()
providing those semantics. Otherwise we at a minimum need to check
for EINTR and EAGAIN, where this is appropriate use xread().
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
We recently introduced a write_in_full() which would either write
the specified object or emit an error message and fail. In order
to fix the read side we now want to introduce a read_in_full()
but without an error emit. This patch cleans up the naming
of this family of calls:
1) convert the existing write_or_whine() to write_or_whine_pipe()
to better indicate its pipe specific nature,
2) convert the existing write_in_full() calls to write_or_whine()
to better indicate its nature,
3) introduce a write_in_full() providing a write or fail semantic,
and
4) convert write_or_whine() and write_or_whine_pipe() to use
write_in_full().
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
* sp/mmap: (27 commits)
Spell default packedgitlimit slightly differently
Increase packedGit{Limit,WindowSize} on 64 bit systems.
Update packedGit config option documentation.
mmap: set FD_CLOEXEC for file descriptors we keep open for mmap()
pack-objects: fix use of use_pack().
Fix random segfaults in pack-objects.
Cleanup read_cache_from error handling.
Replace mmap with xmmap, better handling MAP_FAILED.
Release pack windows before reporting out of memory.
Default core.packdGitWindowSize to 1 MiB if NO_MMAP.
Test suite for sliding window mmap implementation.
Create pack_report() as a debugging aid.
Support unmapping windows on 'temporary' packfiles.
Improve error message when packfile mmap fails.
Ensure core.packedGitWindowSize cannot be less than 2 pages.
Load core configuration in git-verify-pack.
Fully activate the sliding window pack access.
Unmap individual windows rather than entire files.
Document why header parsing won't exceed a window.
Loop over pack_windows when inflating/accessing data.
...
Conflicts:
cache.h
pack-check.c
When passing the revisions list to pack-objects we do not check for
errors nor short writes. Introduce a new write_in_full which will
handle short writes and report errors to the caller. Use this to
short cut the send on failure, allowing us to wait for and report
the child in case the failure is its fault.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Like write_or_die read_or_die reads the entire length requested
or it kills the current process with a die call.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Now if GIT_TRACE is set to an integer value greater than 1
and lower than 10, we interpret this as an open fd value
and we trace into it. Note that this behavior is not
compatible with the previous one.
We also trace whole messages using one write(2) call to
make sure messages from processes do net get mixed up in
the middle.
It's now possible to run the tests like this:
GIT_TRACE=9 make test 9>/var/tmp/trace.log
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
The little helper write_or_die() won't come back with bad news about
full disks or broken pipes. It either succeeds or terminates the
program, making additional error handling unnecessary.
This patch adds the new function and uses it to replace two similar
ones (the one in tar-tree originally has been copied from cat-file
btw.). I chose to add the fd parameter which both lacked to make
write_or_die() just as flexible as write() and thus suitable for
lib-ification.
There is a regression: error messages emitted by this function don't
show the program name, while the replaced two functions did. That's
acceptable, I think; a lot of other functions do the same.
Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <junkio@cox.net>
