f2fs: introduce F2FS_IOC_RELEASE_COMPRESS_BLOCKS

There are still reserved blocks on compressed inode, this patch
introduce a new ioctl to help release reserved blocks back to
filesystem, so that userspace can reuse those freed space.

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Daeho fixed a bug like below.

Now, if writing pages and releasing compress blocks occur
simultaneously, and releasing cblocks is executed more than one time
to a file, then total block count of filesystem and block count of the
file could be incorrect and damaged.

We have to execute releasing compress blocks only one time for a file
without being interfered by writepages path.
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Signed-off-by: Chao Yu <[email protected]>
Signed-off-by: Daeho Jeong <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>

0 files changed, 0 insertions, 0 deletions