# git rev-parse -q --verify 981ee95cc1f5905ae4936b0dd501085909cdc14f^{commit}
# git fetch -q -n -f git://fs.ozlabs.ibm.com/kernel/linus master
warning: The last gc run reported the following. Please correct the root cause
and remove .git/gc.log.
Automatic cleanup will not be performed until the file is removed.

warning: There are too many unreachable loose objects; run 'git prune' to remove them.

# git rev-parse -q --verify 981ee95cc1f5905ae4936b0dd501085909cdc14f^{commit}
981ee95cc1f5905ae4936b0dd501085909cdc14f
# git checkout -q -f -B kisskb 981ee95cc1f5905ae4936b0dd501085909cdc14f
# git clean -qxdf
# < git log -1
# commit 981ee95cc1f5905ae4936b0dd501085909cdc14f
# Author: Mateusz Guzik <mjguzik@gmail.com>
# Date:   Wed Jan 25 16:55:57 2023 +0100
# 
#     vfs: avoid duplicating creds in faccessat if possible
#     
#     access(2) remains commonly used, for example on exec:
#     access("/etc/ld.so.preload", R_OK)
#     
#     or when running gcc: strace -c gcc empty.c
#     
#       % time     seconds  usecs/call     calls    errors syscall
#       ------ ----------- ----------- --------- --------- ----------------
#         0.00    0.000000           0        42        26 access
#     
#     It falls down to do_faccessat without the AT_EACCESS flag, which in turn
#     results in allocation of new creds in order to modify fsuid/fsgid and
#     caps.  This is a very expensive process single-threaded and most notably
#     multi-threaded, with numerous structures getting refed and unrefed on
#     imminent new cred destruction.
#     
#     Turns out for typical consumers the resulting creds would be identical
#     and this can be checked upfront, avoiding the hard work.
#     
#     An access benchmark plugged into will-it-scale running on Cascade Lake
#     shows:
#     
#         test     proc     before       after
#         access1     1    1310582     2908735    (+121%) # distinct files
#         access1    24    4716491    63822173   (+1353%) # distinct files
#         access2    24    2378041     5370335    (+125%) # same file
#     
#     The above benchmarks are not integrated into will-it-scale, but can be
#     found in a pull request:
#     
#       https://github.com/antonblanchard/will-it-scale/pull/36/files
#     
#     Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
#     Cc: Al Viro <viro@zeniv.linux.org.uk>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/korg/gcc-11.3.0-nolibc/sparc64-linux/bin/sparc64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-11.3.0-nolibc/sparc64-linux/bin/sparc64-linux-ld --version
# < git log --format=%s --max-count=1 981ee95cc1f5905ae4936b0dd501085909cdc14f
# < make -s -j 160 ARCH=sparc O=/kisskb/build/linus_sparc-allmodconfig_sparc64-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.3.0-nolibc/sparc64-linux/bin/sparc64-linux-  allmodconfig
# Added to kconfig CONFIG_64BIT=n
# Added to kconfig CONFIG_BUILD_DOCSRC=n
# Added to kconfig CONFIG_HAVE_FTRACE_MCOUNT_RECORD=n
# Added to kconfig CONFIG_SAMPLES=n
# Added to kconfig CONFIG_MODULE_SIG=n
# < make -s -j 160 ARCH=sparc O=/kisskb/build/linus_sparc-allmodconfig_sparc64-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.3.0-nolibc/sparc64-linux/bin/sparc64-linux-  help
# make -s -j 160 ARCH=sparc O=/kisskb/build/linus_sparc-allmodconfig_sparc64-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.3.0-nolibc/sparc64-linux/bin/sparc64-linux-  olddefconfig
# make -s -j 160 ARCH=sparc O=/kisskb/build/linus_sparc-allmodconfig_sparc64-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.3.0-nolibc/sparc64-linux/bin/sparc64-linux-  
<stdin>:1517:2: warning: #warning syscall clone3 not implemented [-Wcpp]
/kisskb/src/fs/btrfs/inode.c: In function 'btrfs_lookup_dentry':
/kisskb/src/fs/btrfs/inode.c:5730:21: error: 'location.type' may be used uninitialized [-Werror=maybe-uninitialized]
 5730 |         if (location.type == BTRFS_INODE_ITEM_KEY) {
      |             ~~~~~~~~^~~~~
/kisskb/src/fs/btrfs/inode.c:5719:26: note: 'location' declared here
 5719 |         struct btrfs_key location;
      |                          ^~~~~~~~
cc1: all warnings being treated as errors
make[4]: *** [/kisskb/src/scripts/Makefile.build:252: fs/btrfs/inode.o] Error 1
make[4]: *** Waiting for unfinished jobs....
make[3]: *** [/kisskb/src/scripts/Makefile.build:494: fs/btrfs] Error 2
make[2]: *** [/kisskb/src/scripts/Makefile.build:494: fs] Error 2
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [/kisskb/src/Makefile:2028: .] Error 2
make: *** [Makefile:226: __sub-make] Error 2
Command 'make -s -j 160 ARCH=sparc O=/kisskb/build/linus_sparc-allmodconfig_sparc64-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.3.0-nolibc/sparc64-linux/bin/sparc64-linux-  ' returned non-zero exit status 2
# rm -rf /kisskb/build/linus_sparc-allmodconfig_sparc64-gcc11
# Build took: 0:04:56.501333