Re: XFS assertion from truncate. (3.10-rc2)

[Dave Jones <davej@redhat.com>]

On Thu, May 23, 2013 at 07:54:54AM +1000, Dave Chinner wrote:

 > Gah, I've got not idea what the hell I was smoking yesterday
 > afternoon. 0x2000 is actually ATTR_FILE, and 0x8000 is ATTR_OPEN.
 > 
 > So a mask of 0xa068 is correct and valid from the open path, and
 > 0x2068 is just file from the truncate path.
 > 
 > But, neither of those should trigger that assert. indeed, on a test
 > kernel (3.10-rc2 based):
 > 
 > # echo I need a new drug > /mnt/scr/bah/blah/black/sheep/foo
 > [  296.742990] XFS (vdb): xfs_setattr_size: mask 0xa068, masked # 0x0 ii 0xffff88003e6297c0, d 0xffff88003e5b9cb0 path /bah/blah/black/sheep/foo
 > #
 > 
 > And there's not assert failure. Indeed, the "masked # 0x0" is what
 > the assert is checking.
 > 
 > And yeah, path output works. Trick for anyone who doesn't read the
 > code closely - the buffer is filled from the end backwards, and the
 > start of the path is the return variable. So, the above code is:
 > 
 > 	{
 > 		struct dentry *d = d_find_alias(VFS_I(ip));
 > 		char buf[MAXPATHLEN];
 > 		char *ptr;
 > 
 > 		memset(buf, 0, MAXPATHLEN);
 > 		ptr = dentry_path(d, buf, MAXPATHLEN);
 > 		xfs_warn(mp, "%s: mask 0x%x, masked 0x%x ii 0x%p, d 0x%p path %s",
 > 			__func__, mask,
 > 	(mask & (ATTR_MODE|ATTR_UID|ATTR_GID|ATTR_ATIME|ATTR_ATIME_SET|
 > 			ATTR_MTIME_SET|ATTR_KILL_SUID|ATTR_KILL_SGID|
 > 			ATTR_KILL_PRIV|ATTR_TIMES_SET)),
 > 			ip, d, ptr);
 > 		dput(d);
 > 	}
 > 
 > Which I put just before the assert that is firing on your machine.
 > 
 > And, obviously, it isn't firing on mine and obviously shouldn't be firing on a
 > mask of 0xa068.

With this, I get a spew of these when I start a kernel build..

[  964.378690] XFS (sda2): xfs_setattr_size: mask 0xa068, masked 0x0 ii 0xffff88020a95dac0, d 0xffff880221b5d970 path /davej/tmp/ccN2RrM5.s
[  964.651927] XFS (sda2): xfs_setattr_size: mask 0xa068, masked 0x0 ii 0xffff88020a95dac0, d 0xffff88020ff80b90 path /davej/tmp/ccB1Cdmo.s
[  964.867444] XFS (sda2): xfs_setattr_size: mask 0xa068, masked 0x0 ii 0xffff88020a95dac0, d 0xffff8802218a5bc0 path /davej/tmp/ccCUaXbG.s
[  965.102661] XFS (sda2): xfs_setattr_size: mask 0xa068, masked 0x0 ii 0xffff88020a95dac0, d 0xffff88020ffacde0 path /davej/tmp/cckMLf2X.s
[  967.743312] XFS (sda2): xfs_setattr_size: mask 0xa068, masked 0x0 ii 0xffff88020a93c200, d 0xffff88022212c250 path /davej/tmp/ccFMkBbA.s
[  967.947154] XFS (sda2): xfs_setattr_size: mask 0xa068, masked 0x0 ii 0xffff88020a93c200, d 0xffff8802226cc6f0 path /davej/tmp/cc5iX4SR.s
[  968.009414] XFS (sda2): xfs_setattr_size: mask 0xa068, masked 0x0 ii 0xffff88020a988000, d 0xffff8802219f1970 path /davej/tmp/ccvWCHTZ.o
[  968.091504] XFS (sda2): xfs_setattr_size: mask 0xa068, masked 0x0 ii 0xffff88020a9898c0, d 0xffff88022208de10 path /davej/tmp/cc9n6fnm.ld
[  968.107997] XFS (sda2): xfs_setattr_size: mask 0xa068, masked 0x0 ii 0xffff88020a98dac0, d 0xffff880221160de0 path /davej/tmp/cc5rlvHu.le

	Dave