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Filename Latest commit message Latest commit date
Filipe Manana 19d8412679 Btrfs: send, allow clone operations within the same file
commit 11f2069c113e02971b8db6fda62f9b9cd31a030f upstream.

For send we currently skip clone operations when the source and
destination files are the same. This is so because clone didn't support
this case in its early days, but support for it was added back in May
2013 by commit a96fbc7288 ("Btrfs: allow file data clone within a
file"). This change adds support for it.

Example:

  $ mkfs.btrfs -f /dev/sdd
  $ mount /dev/sdd /mnt/sdd

  $ xfs_io -f -c "pwrite -S 0xab -b 64K 0 64K" /mnt/sdd/foobar
  $ xfs_io -c "reflink /mnt/sdd/foobar 0 64K 64K" /mnt/sdd/foobar

  $ btrfs subvolume snapshot -r /mnt/sdd /mnt/sdd/snap

  $ mkfs.btrfs -f /dev/sde
  $ mount /dev/sde /mnt/sde

  $ btrfs send /mnt/sdd/snap | btrfs receive /mnt/sde

Without this change file foobar at the destination has a single 128Kb
extent:

  $ filefrag -v /mnt/sde/snap/foobar
  Filesystem type is: 9123683e
  File size of /mnt/sde/snap/foobar is 131072 (32 blocks of 4096 bytes)
   ext:     logical_offset:        physical_offset: length:   expected: flags:
     0:        0..      31:          0..        31:     32:             last,unknown_loc,delalloc,eof
  /mnt/sde/snap/foobar: 1 extent found

With this we get a single 64Kb extent that is shared at file offsets 0
and 64K, just like in the source filesystem:

  $ filefrag -v /mnt/sde/snap/foobar
  Filesystem type is: 9123683e
  File size of /mnt/sde/snap/foobar is 131072 (32 blocks of 4096 bytes)
   ext:     logical_offset:        physical_offset: length:   expected: flags:
     0:        0..      15:       3328..      3343:     16:             shared
     1:       16..      31:       3328..      3343:     16:       3344: last,shared,eof
  /mnt/sde/snap/foobar: 2 extents found

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-14 10:32:59 +02:00
arch arm64: dts: stratix10: add status to qspi dts node 2020-10-14 10:32:59 +02:00
block block/diskstats: more accurate approximation of io_ticks for slow disks 2020-10-07 08:01:29 +02:00
certs
crypto crypto: af_alg - Work around empty control messages without MSG_MORE 2020-09-03 11:27:05 +02:00
Documentation block/diskstats: more accurate approximation of io_ticks for slow disks 2020-10-07 08:01:29 +02:00
drivers i2c: i801: Exclude device from suspend direct complete optimization 2020-10-14 10:32:59 +02:00
fs Btrfs: send, allow clone operations within the same file 2020-10-14 10:32:59 +02:00
include bpf: Prevent .BTF section elimination 2020-10-14 10:32:58 +02:00
init kprobes: tracing/kprobes: Fix to kill kprobes on initmem after boot 2020-10-01 13:18:23 +02:00
ipc
kernel bpf: Fix sysfs export of empty BTF section 2020-10-14 10:32:58 +02:00
lib Fonts: Support FONT_EXTRA_WORDS macros for built-in fonts 2020-10-14 10:32:56 +02:00
LICENSES
mm mm: don't rely on system state to detect hot-plug operations 2020-10-07 08:01:30 +02:00
net net: wireless: nl80211: fix out-of-bounds access in nl80211_del_key() 2020-10-14 10:32:57 +02:00
samples bpf: Fix fds_example SIGSEGV error 2020-08-19 08:16:03 +02:00
scripts scripts/dtc: only append to HOST_EXTRACFLAGS instead of overwriting 2020-10-07 08:01:29 +02:00
security device_cgroup: Fix RCU list debugging warning 2020-10-01 13:18:13 +02:00
sound ALSA: hda/realtek: Enable front panel headset LED on Lenovo ThinkStation P520 2020-10-01 13:18:22 +02:00
tools perf top: Fix stdio interface input handling with glibc 2.28+ 2020-10-14 10:32:59 +02:00
usr
virt KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch 2020-10-01 13:18:25 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.70 2020-10-07 08:01:31 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.