gfs2: keep bios separate for each journal

The recovery func can recover multiple journals, but they were all using
the same bio. This resulted in use-after-free related to sdp->sd_log_bio.
This patch moves the variable to the journal descriptor, jd, so that
every recovery can operate on its own bio. And hopefully we never run out.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>

fs/gfs2/incore.h

@@ -531,6 +531,7 @@ struct gfs2_jdesc {
 	unsigned int nr_extents;
 	struct work_struct jd_work;
 	struct inode *jd_inode;
+	struct bio *jd_log_bio;
 	unsigned long jd_flags;
 #define JDF_RECOVERY 1
 	unsigned int jd_jid;
@@ -844,7 +845,6 @@ struct gfs2_sbd {
 
 	struct rw_semaphore sd_log_flush_lock;
 	atomic_t sd_log_in_flight;
-	struct bio *sd_log_bio;
 	wait_queue_head_t sd_log_flush_wait;
 	int sd_log_error; /* First log error */
 	wait_queue_head_t sd_withdraw_wait;

fs/gfs2/log.c

@@ -822,8 +822,8 @@ void gfs2_write_log_header(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd,
 		     sb->s_blocksize - LH_V1_SIZE - 4);
 	lh->lh_crc = cpu_to_be32(crc);
 
-	gfs2_log_write(sdp, page, sb->s_blocksize, 0, dblock);
-	gfs2_log_submit_bio(&sdp->sd_log_bio, REQ_OP_WRITE | op_flags);
+	gfs2_log_write(sdp, jd, page, sb->s_blocksize, 0, dblock);
+	gfs2_log_submit_bio(&jd->jd_log_bio, REQ_OP_WRITE | op_flags);
 out:
 	log_flush_wait(sdp);
 }
@@ -999,7 +999,7 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags)
 	lops_before_commit(sdp, tr);
 	if (gfs2_withdrawn(sdp))
 		goto out_withdraw;
-	gfs2_log_submit_bio(&sdp->sd_log_bio, REQ_OP_WRITE);
+	gfs2_log_submit_bio(&sdp->sd_jdesc->jd_log_bio, REQ_OP_WRITE);
 	if (gfs2_withdrawn(sdp))
 		goto out_withdraw;
 

fs/gfs2/lops.c

@@ -322,17 +322,18 @@ static struct bio *gfs2_log_get_bio(struct gfs2_sbd *sdp, u64 blkno,
  * then add the page segment to that.
  */
 
-void gfs2_log_write(struct gfs2_sbd *sdp, struct page *page,
-		    unsigned size, unsigned offset, u64 blkno)
+void gfs2_log_write(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd,
+		    struct page *page, unsigned size, unsigned offset,
+		    u64 blkno)
 {
 	struct bio *bio;
 	int ret;
 
-	bio = gfs2_log_get_bio(sdp, blkno, &sdp->sd_log_bio, REQ_OP_WRITE,
+	bio = gfs2_log_get_bio(sdp, blkno, &jd->jd_log_bio, REQ_OP_WRITE,
 			       gfs2_end_log_write, false);
 	ret = bio_add_page(bio, page, size, offset);
 	if (ret == 0) {
-		bio = gfs2_log_get_bio(sdp, blkno, &sdp->sd_log_bio,
+		bio = gfs2_log_get_bio(sdp, blkno, &jd->jd_log_bio,
 				       REQ_OP_WRITE, gfs2_end_log_write, true);
 		ret = bio_add_page(bio, page, size, offset);
 		WARN_ON(ret == 0);
@@ -355,7 +356,8 @@ static void gfs2_log_write_bh(struct gfs2_sbd *sdp, struct buffer_head *bh)
 
 	dblock = gfs2_log_bmap(sdp->sd_jdesc, sdp->sd_log_flush_head);
 	gfs2_log_incr_head(sdp);
-	gfs2_log_write(sdp, bh->b_page, bh->b_size, bh_offset(bh), dblock);
+	gfs2_log_write(sdp, sdp->sd_jdesc, bh->b_page, bh->b_size,
+		       bh_offset(bh), dblock);
 }
 
 /**
@@ -376,7 +378,7 @@ static void gfs2_log_write_page(struct gfs2_sbd *sdp, struct page *page)
 
 	dblock = gfs2_log_bmap(sdp->sd_jdesc, sdp->sd_log_flush_head);
 	gfs2_log_incr_head(sdp);
-	gfs2_log_write(sdp, page, sb->s_blocksize, 0, dblock);
+	gfs2_log_write(sdp, sdp->sd_jdesc, page, sb->s_blocksize, 0, dblock);
 }
 
 /**

fs/gfs2/lops.h

@@ -20,8 +20,9 @@
 extern const struct gfs2_log_operations *gfs2_log_ops[];
 extern void gfs2_log_incr_head(struct gfs2_sbd *sdp);
 extern u64 gfs2_log_bmap(struct gfs2_jdesc *jd, unsigned int lbn);
-extern void gfs2_log_write(struct gfs2_sbd *sdp, struct page *page,
-			   unsigned size, unsigned offset, u64 blkno);
+extern void gfs2_log_write(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd,
+			   struct page *page, unsigned size, unsigned offset,
+			   u64 blkno);
 extern void gfs2_log_submit_bio(struct bio **biop, int opf);
 extern void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh);
 extern int gfs2_find_jhead(struct gfs2_jdesc *jd,

fs/gfs2/recovery.c

@@ -505,7 +505,7 @@ void gfs2_recover_func(struct work_struct *work)
 
 		/* We take the sd_log_flush_lock here primarily to prevent log
 		 * flushes and simultaneous journal replays from stomping on
-		 * each other wrt sd_log_bio. */
+		 * each other wrt jd_log_bio. */
 		down_read(&sdp->sd_log_flush_lock);
 		for (pass = 0; pass < 2; pass++) {
 			lops_before_scan(jd, &head, pass);