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Zheng Liu dda5690def ext3: fix a BUG when opening a file with O_TMPFILE flag 
When we try to open a file with O_TMPFILE flag, we will trigger a bug.
The root cause is that in ext4_orphan_add() we check ->i_nlink == 0 and
this check always fails because we set ->i_nlink = 1 in
inode_init_always().  We can use the following program to trigger it:

int main(int argc, char *argv[])
{
	int fd;

	fd = open(argv[1], O_TMPFILE, 0666);
	if (fd < 0) {
		perror("open ");
		return -1;
	}
	close(fd);
	return 0;
}

The oops message looks like this:

kernel: kernel BUG at fs/ext3/namei.c:1992!
kernel: invalid opcode: 0000 [#1] SMP
kernel: Modules linked in: ext4 jbd2 crc16 cpufreq_ondemand ipv6 dm_mirror dm_region_hash dm_log dm_mod parport_pc parport serio_raw sg dcdbas pcspkr i2c_i801 ehci_pci ehci_hcd button acpi_cpufreq mperf e1000e ptp pps_core ttm drm_kms_helper drm hwmon i2c_algo_bit i2c_core ext3 jbd sd_mod ahci libahci libata scsi_mod uhci_hcd
kernel: CPU: 0 PID: 2882 Comm: tst_tmpfile Not tainted 3.11.0-rc1+ #4
kernel: Hardware name: Dell Inc. OptiPlex 780 /0V4W66, BIOS A05 08/11/2010
kernel: task: ffff880112d30050 ti: ffff8801124d4000 task.ti: ffff8801124d4000
kernel: RIP: 0010:[<ffffffffa00db5ae>] [<ffffffffa00db5ae>] ext3_orphan_add+0x6a/0x1eb [ext3]
kernel: RSP: 0018:ffff8801124d5cc8  EFLAGS: 00010202
kernel: RAX: 0000000000000000 RBX: ffff880111510128 RCX: ffff8801114683a0
kernel: RDX: 0000000000000000 RSI: ffff880111510128 RDI: ffff88010fcf65a8
kernel: RBP: ffff8801124d5d18 R08: 0080000000000000 R09: ffffffffa00d3b7f
kernel: R10: ffff8801114683a0 R11: ffff8801032a2558 R12: 0000000000000000
kernel: R13: ffff88010fcf6800 R14: ffff8801032a2558 R15: ffff8801115100d8
kernel: FS:  00007f5d172b5700(0000) GS:ffff880117c00000(0000) knlGS:0000000000000000
kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
kernel: CR2: 00007f5d16df15d0 CR3: 0000000110b1d000 CR4: 00000000000407f0
kernel: Stack:
kernel: 000000000000000c ffff8801048a7dc8 ffff8801114685a8 ffffffffa00b80d7
kernel: ffff8801124d5e38 ffff8801032a2558 ffff88010ce24d68 0000000000000000
kernel: ffff88011146b300 ffff8801124d5d44 ffff8801124d5d78 ffffffffa00db7e1
kernel: Call Trace:
kernel: [<ffffffffa00b80d7>] ? journal_start+0x8c/0xbd [jbd]
kernel: [<ffffffffa00db7e1>] ext3_tmpfile+0xb2/0x13b [ext3]
kernel: [<ffffffff821076f8>] path_openat+0x11f/0x5e7
kernel: [<ffffffff821c86b4>] ? list_del+0x11/0x30
kernel: [<ffffffff82065fa2>] ?  __dequeue_entity+0x33/0x38
kernel: [<ffffffff82107cd5>] do_filp_open+0x3f/0x8d
kernel: [<ffffffff82112532>] ? __alloc_fd+0x50/0x102
kernel: [<ffffffff820f9296>] do_sys_open+0x13b/0x1cd
kernel: [<ffffffff820f935c>] SyS_open+0x1e/0x20
kernel: [<ffffffff82398c02>] system_call_fastpath+0x16/0x1b
kernel: Code: 39 c7 0f 85 67 01 00 00 0f b7 03 25 00 f0 00 00 3d 00 40 00 00 74 18 3d 00 80 00 00 74 11 3d 00 a0 00 00 74 0a 83 7b 48 00 74 04 <0f> 0b eb fe 49 8b 85 50 03 00 00 4c 89 f6 48 c7 c7 c0 99 0e a0
kernel: RIP  [<ffffffffa00db5ae>] ext3_orphan_add+0x6a/0x1eb [ext3]
kernel: RSP <ffff8801124d5cc8>

Here we couldn't call clear_nlink() directly because in d_tmpfile() we
will call inode_dec_link_count() to decrease ->i_nlink.  So this commit
tries to call d_tmpfile() before ext4_orphan_add() to fix this problem.

Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
2013-07-20 22:03:20 -04:00
..
acl.c userns: Convert extN to support kuids and kgids in posix acls 2012-09-18 01:01:36 -07:00
acl.h fs: take the ACL checks to common code 2011-07-25 14:30:23 -04:00
balloc.c ext3: Avoid underflow of in ext3_trim_fs() 2012-11-19 21:36:12 +01:00
bitmap.c ext3: use memweight() 2012-07-30 17:25:16 -07:00
dir.c [readdir] convert ext3 2013-06-29 12:46:49 +04:00
ext3.h Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2012-05-25 08:14:59 -07:00
ext3_jbd.c ext3: move headers to fs/ext3/ 2012-03-31 16:03:16 -04:00
file.c ext3: move headers to fs/ext3/ 2012-03-31 16:03:16 -04:00
fsync.c ext3: Fix fsync error handling after filesystem abort. 2013-07-04 19:22:55 +02:00
hash.c ext3: return 32/64-bit dir name hash according to usage type 2012-05-15 23:34:39 +02:00
ialloc.c ext3: remove max_debt in find_group_orlov() 2012-04-11 11:12:44 +02:00
inode.c mm: vmscan: take page buffers dirty and locked state into account 2013-07-03 16:07:29 -07:00
ioctl.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
Kconfig ext3: default to ordered mode 2010-07-23 12:50:55 +02:00
Makefile
namei.c ext3: fix a BUG when opening a file with O_TMPFILE flag 2013-07-20 22:03:20 -04:00
namei.h ext3: ext3_bread usage audit 2012-10-09 23:21:42 +02:00
resize.c Ext3: return ENOMEM rather than EIO if sb_getblk fails 2013-01-21 11:19:57 +01:00
super.c ext3: Fix fsync error handling after filesystem abort. 2013-07-04 19:22:55 +02:00
symlink.c ext3: move headers to fs/ext3/ 2012-03-31 16:03:16 -04:00
xattr.c Ext3: return ENOMEM rather than EIO if sb_getblk fails 2013-01-21 11:19:57 +01:00
xattr.h fs/vfs/security: pass last path component to LSM on inode creation 2011-02-01 11:12:29 -05:00
xattr_security.c ext3: move headers to fs/ext3/ 2012-03-31 16:03:16 -04:00
xattr_trusted.c ext3: move headers to fs/ext3/ 2012-03-31 16:03:16 -04:00
xattr_user.c ext3: move headers to fs/ext3/ 2012-03-31 16:03:16 -04:00