From: Dmitry Monakhov <dmonakhov@openvz.org>
Date: Tue, 29 Jan 2008 04:58:27 +0000 (-0500)
Subject: ext4: fix uniniatilized extent splitting error
X-Git-Tag: v2.6.25-rc1~1166^2~5
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dbf9d7da33f79302fb1e4d7c6b2f6598e8608e72;p=pandora-kernel.git

ext4: fix uniniatilized extent splitting error

Fix bug reported by Dmitry Monakhov caused by lost error code

    Testcase:

    blksize = 0x1000;
    fd = open(argv[1], O_RDWR|O_CREAT, 0700);
    unsigned long long sz = 0x10000000UL;
    /* allocating big blocks chunk */
    syscall(__NR_fallocate, fd, 0, 0UL, sz)

    /* grab all other available filesystem space */
    tfd = open("tmp", O_RDWR|O_CREAT|O_DIRECT, 0700);
    while( write(tfd, buf, 4096) > 0); /* loop untill ENOSPC */
    fsync(fd); /* just in case */
    while (pos < sz) {
    	/* each seek+ write operation result in splits uninitialized extent
    	in three extents. Splitting may result in new extent allocation
    	which probably will fail because of ENOSPC*/

    	lseek(fd, blksize*2 -1, SEEK_CUR);
    	if ((ret = write(fd, 'a', 1)) != 1)
    		exit(1);
    	pos += blksize * 2;
    }

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---

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