tree 33916ce63fdf1334d5f00dbfc254eacb013a73e4
parent 22a0511779f137b1a8106862506fd6fe81661b35
author Jaegeuk Kim <jaegeuk@kernel.org> 1574452390 -0800
committer Alexander Martinz <amartinz@shiftphones.com> 1632775832 +0200
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f2fs: expose main_blkaddr in sysfs

Expose in /sys/fs/f2fs/<blockdev>/main_blkaddr the block address where the
main area starts. This allows user mode programs to determine:

- That pinned files that are made exclusively of fully allocated 2MB
  segments will never be unpinned by the file system.

- Where the main area starts. This is required by programs that want to
  verify if a file is made exclusively of 2MB f2fs segments, the alignment
  boundary for segments starts at this address. Testing for 2MB alignment
  relative to the start of the device is incorrect, because for some
  filesystems main_blkaddr is not at a 2MB boundary relative to the start
  of the device.

The entry will be used when validating reliable pinning file feature proposed
by "f2fs: support aligned pinned file".

Change-Id: I6652eb68c21a95abf2d0d84bca21bef4dcfc2bcd
Signed-off-by: Ramon Pantin <pantin@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>