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Filipe Manana 5aefd1fa9f Btrfs: send, fix emission of invalid clone operations within the same file
commit 9722b10148 upstream.

When doing an incremental send and a file has extents shared with itself
at different file offsets, it's possible for send to emit clone operations
that will fail at the destination because the source range goes beyond the
file's current size. This happens when the file size has increased in the
send snapshot, there is a hole between the shared extents and both shared
extents are at file offsets which are greater the file's size in the
parent snapshot.

Example:

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

  $ xfs_io -f -c "pwrite -S 0xf1 0 64K" /mnt/sdb/foobar
  $ btrfs subvolume snapshot -r /mnt/sdb /mnt/sdb/base
  $ btrfs send -f /tmp/1.snap /mnt/sdb/base

  # Create a 320K extent at file offset 512K.
  $ xfs_io -c "pwrite -S 0xab 512K 64K" /mnt/sdb/foobar
  $ xfs_io -c "pwrite -S 0xcd 576K 64K" /mnt/sdb/foobar
  $ xfs_io -c "pwrite -S 0xef 640K 64K" /mnt/sdb/foobar
  $ xfs_io -c "pwrite -S 0x64 704K 64K" /mnt/sdb/foobar
  $ xfs_io -c "pwrite -S 0x73 768K 64K" /mnt/sdb/foobar

  # Clone part of that 320K extent into a lower file offset (192K).
  # This file offset is greater than the file's size in the parent
  # snapshot (64K). Also the clone range is a bit behind the offset of
  # the 320K extent so that we leave a hole between the shared extents.
  $ xfs_io -c "reflink /mnt/sdb/foobar 448K 192K 192K" /mnt/sdb/foobar

  $ btrfs subvolume snapshot -r /mnt/sdb /mnt/sdb/incr
  $ btrfs send -p /mnt/sdb/base -f /tmp/2.snap /mnt/sdb/incr

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

  $ btrfs receive -f /tmp/1.snap /mnt/sdc
  $ btrfs receive -f /tmp/2.snap /mnt/sdc
  ERROR: failed to clone extents to foobar: Invalid argument

The problem is that after processing the extent at file offset 256K, which
refers to the first 128K of the 320K extent created by the buffered write
operations, we have 'cur_inode_next_write_offset' set to 384K, which
corresponds to the end offset of the partially shared extent (256K + 128K)
and to the current file size in the receiver. Then when we process the
extent at offset 512K, we do extent backreference iteration to figure out
if we can clone the extent from some other inode or from the same inode,
and we consider the extent at offset 256K of the same inode as a valid
source for a clone operation, which is not correct because at that point
the current file size in the receiver is 384K, which corresponds to the
end of last processed extent (at file offset 256K), so using a clone
source range from 256K to 256K + 320K is invalid because that goes past
the current size of the file (384K) - this makes the receiver get an
-EINVAL error when attempting the clone operation.

So fix this by excluding clone sources that have a range that goes beyond
the current file size in the receiver when iterating extent backreferences.

A test case for fstests follows soon.

Fixes: 11f2069c11 ("Btrfs: send, allow clone operations within the same file")
CC: stable@vger.kernel.org # 5.5+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@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 PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
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, fix emission of invalid 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 ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
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 LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
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 initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch 2020-10-01 13:18:25 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
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 Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.