Revision fd45e4784164d1017521086524e3442318c67370 authored by Dave Chinner on 02 January 2010, 02:38:56 UTC, committed by Alex Elder on 10 January 2010, 18:22:02 UTC
When we search for and find a busy extent during allocation we force the log out to ensure the extent free transaction is on disk before the allocation transaction. The current implementation has a subtle bug in it--it does not handle multiple overlapping ranges. That is, if we free lots of little extents into a single contiguous extent, then allocate the contiguous extent, the busy search code stops searching at the first extent it finds that overlaps the allocated range. It then uses the commit LSN of the transaction to force the log out to. Unfortunately, the other busy ranges might have more recent commit LSNs than the first busy extent that is found, and this results in xfs_alloc_search_busy() returning before all the extent free transactions are on disk for the range being allocated. This can lead to potential metadata corruption or stale data exposure after a crash because log replay won't replay all the extent free transactions that cover the allocation range. Modified-by: Alex Elder <aelder@sgi.com> (Dropped the "found" argument from the xfs_alloc_busysearch trace event.) Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
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scsi_eh.h
#ifndef _SCSI_SCSI_EH_H
#define _SCSI_SCSI_EH_H
#include <linux/scatterlist.h>
#include <scsi/scsi_cmnd.h>
struct scsi_device;
struct Scsi_Host;
/*
* This is a slightly modified SCSI sense "descriptor" format header.
* The addition is to allow the 0x70 and 0x71 response codes. The idea
* is to place the salient data from either "fixed" or "descriptor" sense
* format into one structure to ease application processing.
*
* The original sense buffer should be kept around for those cases
* in which more information is required (e.g. the LBA of a MEDIUM ERROR).
*/
struct scsi_sense_hdr { /* See SPC-3 section 4.5 */
u8 response_code; /* permit: 0x0, 0x70, 0x71, 0x72, 0x73 */
u8 sense_key;
u8 asc;
u8 ascq;
u8 byte4;
u8 byte5;
u8 byte6;
u8 additional_length; /* always 0 for fixed sense format */
};
static inline int scsi_sense_valid(struct scsi_sense_hdr *sshdr)
{
if (!sshdr)
return 0;
return (sshdr->response_code & 0x70) == 0x70;
}
extern void scsi_eh_finish_cmd(struct scsi_cmnd *scmd,
struct list_head *done_q);
extern void scsi_eh_flush_done_q(struct list_head *done_q);
extern void scsi_report_bus_reset(struct Scsi_Host *, int);
extern void scsi_report_device_reset(struct Scsi_Host *, int, int);
extern int scsi_block_when_processing_errors(struct scsi_device *);
extern int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
struct scsi_sense_hdr *sshdr);
extern int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
struct scsi_sense_hdr *sshdr);
static inline int scsi_sense_is_deferred(struct scsi_sense_hdr *sshdr)
{
return ((sshdr->response_code >= 0x70) && (sshdr->response_code & 1));
}
extern const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
int desc_type);
extern int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
u64 * info_out);
extern void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq);
/*
* Reset request from external source
*/
#define SCSI_TRY_RESET_DEVICE 1
#define SCSI_TRY_RESET_BUS 2
#define SCSI_TRY_RESET_HOST 3
#define SCSI_TRY_RESET_TARGET 4
extern int scsi_reset_provider(struct scsi_device *, int);
struct scsi_eh_save {
/* saved state */
int result;
enum dma_data_direction data_direction;
unsigned underflow;
unsigned char cmd_len;
unsigned char prot_op;
unsigned char *cmnd;
struct scsi_data_buffer sdb;
struct request *next_rq;
/* new command support */
unsigned char eh_cmnd[BLK_MAX_CDB];
struct scatterlist sense_sgl;
};
extern void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd,
struct scsi_eh_save *ses, unsigned char *cmnd,
int cmnd_size, unsigned sense_bytes);
extern void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd,
struct scsi_eh_save *ses);
#endif /* _SCSI_SCSI_EH_H */
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