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Commit 40e0e61e authored by Abhi Das's avatar Abhi Das Committed by Andreas Gruenbacher
Browse files

gfs2: add a helper function to get_log_header that can be used elsewhere 



Move and re-order the error checks and hash/crc computations into another
function __get_log_header() so it can be used in scenarios where buffer_heads
are not being used for the log header.

Signed-off-by: default avatarAbhi Das <adas@redhat.com>
Signed-off-by: default avatarBob Peterson <rpeterso@redhat.com>
Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
parent 5b846095

fs/gfs2/recovery.c

+32 −21
Original line number Diff line number Diff line
@@ -120,6 +120,35 @@ void gfs2_revoke_clean(struct gfs2_jdesc *jd) 
	}

}



int __get_log_header(struct gfs2_sbd *sdp, const struct gfs2_log_header *lh,

		     unsigned int blkno, struct gfs2_log_header_host *head)

{

	u32 hash, crc;



	if (lh->lh_header.mh_magic != cpu_to_be32(GFS2_MAGIC) ||

	    lh->lh_header.mh_type != cpu_to_be32(GFS2_METATYPE_LH) ||

	    (blkno && be32_to_cpu(lh->lh_blkno) != blkno))

		return 1;



	hash = crc32(~0, lh, LH_V1_SIZE - 4);

	hash = ~crc32_le_shift(hash, 4); /* assume lh_hash is zero */



	if (be32_to_cpu(lh->lh_hash) != hash)

		return 1;



	crc = crc32c(~0, (void *)lh + LH_V1_SIZE + 4,

		     sdp->sd_sb.sb_bsize - LH_V1_SIZE - 4);



	if ((lh->lh_crc != 0 && be32_to_cpu(lh->lh_crc) != crc))

		return 1;



	head->lh_sequence = be64_to_cpu(lh->lh_sequence);

	head->lh_flags = be32_to_cpu(lh->lh_flags);

	head->lh_tail = be32_to_cpu(lh->lh_tail);

	head->lh_blkno = be32_to_cpu(lh->lh_blkno);



	return 0;

}

/**

 * get_log_header - read the log header for a given segment

 * @jd: the journal
@@ -137,36 +166,18 @@ void gfs2_revoke_clean(struct gfs2_jdesc *jd) 
static int get_log_header(struct gfs2_jdesc *jd, unsigned int blk,

			  struct gfs2_log_header_host *head)

{

	struct gfs2_log_header *lh;

	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);

	struct buffer_head *bh;

	u32 hash, crc;

	int error;



	error = gfs2_replay_read_block(jd, blk, &bh);

	if (error)

		return error;

	lh = (void *)bh->b_data;



	hash = crc32(~0, lh, LH_V1_SIZE - 4);

	hash = ~crc32_le_shift(hash, 4);  /* assume lh_hash is zero */



	crc = crc32c(~0, (void *)lh + LH_V1_SIZE + 4,

		     bh->b_size - LH_V1_SIZE - 4);



	error = lh->lh_header.mh_magic != cpu_to_be32(GFS2_MAGIC) ||

		lh->lh_header.mh_type != cpu_to_be32(GFS2_METATYPE_LH) ||

		be32_to_cpu(lh->lh_blkno) != blk ||

		be32_to_cpu(lh->lh_hash) != hash ||

		(lh->lh_crc != 0 && be32_to_cpu(lh->lh_crc) != crc);



	error = __get_log_header(sdp, (const struct gfs2_log_header *)bh->b_data,

				 blk, head);

	brelse(bh);



	if (!error) {

		head->lh_sequence = be64_to_cpu(lh->lh_sequence);

		head->lh_flags = be32_to_cpu(lh->lh_flags);

		head->lh_tail = be32_to_cpu(lh->lh_tail);

		head->lh_blkno = be32_to_cpu(lh->lh_blkno);

	}

	return error;

}

fs/gfs2/recovery.h

+3 −0
Original line number Diff line number Diff line
@@ -31,6 +31,9 @@ extern int gfs2_find_jhead(struct gfs2_jdesc *jd, 
		    struct gfs2_log_header_host *head);

extern int gfs2_recover_journal(struct gfs2_jdesc *gfs2_jd, bool wait);

extern void gfs2_recover_func(struct work_struct *work);

extern int __get_log_header(struct gfs2_sbd *sdp,

			    const struct gfs2_log_header *lh, unsigned int blkno,

			    struct gfs2_log_header_host *head);



#endif /* __RECOVERY_DOT_H__ */