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Revision 7ce9d5d1f3c8736511daa413c64985a05b2feee3 authored by Eric Sandeen on 04 March 2009, 23:38:18 UTC, committed by Theodore Ts'o on 04 March 2009, 23:38:18 UTC 
ext4: fix ext4_free_inode() vs. ext4_claim_inode() race
 
I was seeing fsck errors on inode bitmaps after a 4 thread
dbench run on a 4 cpu machine:

Inode bitmap differences: -50736 -(50752--50753) etc...

I believe that this is because ext4_free_inode() uses atomic
bitops, and although ext4_new_inode() *used* to also use atomic 
bitops for synchronization, commit 
393418676a7602e1d7d3f6e560159c65c8cbd50e changed this to use
the sb_bgl_lock, so that we could also synchronize against
read_inode_bitmap and initialization of uninit inode tables.

However, that change left ext4_free_inode using atomic bitops,
which I think leaves no synchronization between setting & 
unsetting bits in the inode table.

The below patch fixes it for me, although I wonder if we're 
getting at all heavy-handed with this spinlock...

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
1 parent fec6c6f
Raw File
scsi_ioctl.h 
#ifndef _SCSI_IOCTL_H
#define _SCSI_IOCTL_H 

#define SCSI_IOCTL_SEND_COMMAND 1
#define SCSI_IOCTL_TEST_UNIT_READY 2
#define SCSI_IOCTL_BENCHMARK_COMMAND 3
#define SCSI_IOCTL_SYNC 4			/* Request synchronous parameters */
#define SCSI_IOCTL_START_UNIT 5
#define SCSI_IOCTL_STOP_UNIT 6
/* The door lock/unlock constants are compatible with Sun constants for
   the cdrom */
#define SCSI_IOCTL_DOORLOCK 0x5380		/* lock the eject mechanism */
#define SCSI_IOCTL_DOORUNLOCK 0x5381		/* unlock the mechanism	  */

#define	SCSI_REMOVAL_PREVENT	1
#define	SCSI_REMOVAL_ALLOW	0

#ifdef __KERNEL__

struct scsi_device;

/*
 * Structures used for scsi_ioctl et al.
 */

typedef struct scsi_ioctl_command {
	unsigned int inlen;
	unsigned int outlen;
	unsigned char data[0];
} Scsi_Ioctl_Command;

typedef struct scsi_idlun {
	__u32 dev_id;
	__u32 host_unique_id;
} Scsi_Idlun;

/* Fibre Channel WWN, port_id struct */
typedef struct scsi_fctargaddress {
	__u32 host_port_id;
	unsigned char host_wwn[8]; // include NULL term.
} Scsi_FCTargAddress;

extern int scsi_ioctl(struct scsi_device *, int, void __user *);
extern int scsi_nonblockable_ioctl(struct scsi_device *sdev, int cmd,
				   void __user *arg, int ndelay);

#endif /* __KERNEL__ */
#endif /* _SCSI_IOCTL_H */
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