From: Dmitry Monakhov <dmonakhov@openvz.org>
Date: Tue, 2 Dec 2014 23:08:53 +0000 (-0500)
Subject: ext4: fix suboptimal seek_{data,hole} extents traversial
X-Git-Tag: omap-for-v3.19/fixes-rc1~116^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=14516bb7bb6ffbd49f35389f9ece3b2045ba5815;p=pandora-kernel.git

ext4: fix suboptimal seek_{data,hole} extents traversial

It is ridiculous practice to scan inode block by block, this technique
applicable only for old indirect files. This takes significant amount
of time for really large files. Let's reuse ext4_fiemap which already
traverse inode-tree in most optimal meaner.

TESTCASE:
ftruncate64(fd, 0);
ftruncate64(fd, 1ULL << 40);
/* lseek will spin very long time */
lseek64(fd, 0, SEEK_DATA);
lseek64(fd, 0, SEEK_HOLE);

Original report: https://lkml.org/lkml/2014/10/16/620

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---

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