1 files changed, 102 insertions, 27 deletions

diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 291415ddfe51..f49a12e24086 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -83,6 +83,11 @@ static void gfs2_ail1_start_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
 
                         gfs2_assert(sdp, bd->bd_ail == ai);
 
+                        if (!bh){
+                                list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
+                                continue;
+                        }
+
                         if (!buffer_busy(bh)) {
                                 if (!buffer_uptodate(bh)) {
                                         gfs2_log_unlock(sdp);
@@ -125,6 +130,11 @@ static int gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai, int fl
                                          bd_ail_st_list) {
                 bh = bd->bd_bh;
 
+                if (!bh){
+                        list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
+                        continue;
+                }
+
                 gfs2_assert(sdp, bd->bd_ail == ai);
 
                 if (buffer_busy(bh)) {
@@ -262,8 +272,8 @@ static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
  * @sdp: The GFS2 superblock
  * @blks: The number of blocks to reserve
  *
- * Note that we never give out the last 6 blocks of the journal. Thats
- * due to the fact that there is are a small number of header blocks
+ * Note that we never give out the last few blocks of the journal. Thats
+ * due to the fact that there is a small number of header blocks
  * associated with each log flush. The exact number can't be known until
  * flush time, so we ensure that we have just enough free blocks at all
  * times to avoid running out during a log flush.
@@ -274,6 +284,7 @@ static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
 int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
 {
         unsigned int try = 0;
+        unsigned reserved_blks = 6 * (4096 / sdp->sd_vfs->s_blocksize);
 
         if (gfs2_assert_warn(sdp, blks) ||
             gfs2_assert_warn(sdp, blks <= sdp->sd_jdesc->jd_blocks))
@@ -281,7 +292,7 @@ int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
 
         mutex_lock(&sdp->sd_log_reserve_mutex);
         gfs2_log_lock(sdp);
-        while(sdp->sd_log_blks_free <= (blks + 6)) {
+        while(sdp->sd_log_blks_free <= (blks + reserved_blks)) {
                 gfs2_log_unlock(sdp);
                 gfs2_ail1_empty(sdp, 0);
                 gfs2_log_flush(sdp, NULL);
@@ -357,6 +368,58 @@ static inline unsigned int log_distance(struct gfs2_sbd *sdp, unsigned int newer
         return dist;
 }
 
+/**
+ * calc_reserved - Calculate the number of blocks to reserve when
+ *                 refunding a transaction's unused buffers.
+ * @sdp: The GFS2 superblock
+ *
+ * This is complex.  We need to reserve room for all our currently used
+ * metadata buffers (e.g. normal file I/O rewriting file time stamps) and 
+ * all our journaled data buffers for journaled files (e.g. files in the 
+ * meta_fs like rindex, or files for which chattr +j was done.)
+ * If we don't reserve enough space, gfs2_log_refund and gfs2_log_flush
+ * will count it as free space (sd_log_blks_free) and corruption will follow.
+ *
+ * We can have metadata bufs and jdata bufs in the same journal.  So each
+ * type gets its own log header, for which we need to reserve a block.
+ * In fact, each type has the potential for needing more than one header 
+ * in cases where we have more buffers than will fit on a journal page.
+ * Metadata journal entries take up half the space of journaled buffer entries.
+ * Thus, metadata entries have buf_limit (502) and journaled buffers have
+ * databuf_limit (251) before they cause a wrap around.
+ *
+ * Also, we need to reserve blocks for revoke journal entries and one for an
+ * overall header for the lot.
+ *
+ * Returns: the number of blocks reserved
+ */
+static unsigned int calc_reserved(struct gfs2_sbd *sdp)
+{
+        unsigned int reserved = 0;
+        unsigned int mbuf_limit, metabufhdrs_needed;
+        unsigned int dbuf_limit, databufhdrs_needed;
+        unsigned int revokes = 0;
+
+        mbuf_limit = buf_limit(sdp);
+        metabufhdrs_needed = (sdp->sd_log_commited_buf +
+                              (mbuf_limit - 1)) / mbuf_limit;
+        dbuf_limit = databuf_limit(sdp);
+        databufhdrs_needed = (sdp->sd_log_commited_databuf +
+                              (dbuf_limit - 1)) / dbuf_limit;
+
+        if (sdp->sd_log_commited_revoke)
+                revokes = gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
+                                          sizeof(u64));
+
+        reserved = sdp->sd_log_commited_buf + metabufhdrs_needed +
+                sdp->sd_log_commited_databuf + databufhdrs_needed +
+                revokes;
+        /* One for the overall header */
+        if (reserved)
+                reserved++;
+        return reserved;
+}
+
 static unsigned int current_tail(struct gfs2_sbd *sdp)
 {
         struct gfs2_ail *ai;
@@ -447,14 +510,14 @@ struct buffer_head *gfs2_log_fake_buf(struct gfs2_sbd *sdp,
         return bh;
 }
 
-static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail, int pull)
+static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail)
 {
         unsigned int dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
 
         ail2_empty(sdp, new_tail);
 
         gfs2_log_lock(sdp);
-        sdp->sd_log_blks_free += dist - (pull ? 1 : 0);
+        sdp->sd_log_blks_free += dist;
         gfs2_assert_withdraw(sdp, sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
         gfs2_log_unlock(sdp);
 
@@ -504,7 +567,7 @@ static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull)
         brelse(bh);
 
         if (sdp->sd_log_tail != tail)
-                log_pull_tail(sdp, tail, pull);
+                log_pull_tail(sdp, tail);
         else
                 gfs2_assert_withdraw(sdp, !pull);
 
@@ -517,6 +580,7 @@ static void log_flush_commit(struct gfs2_sbd *sdp)
         struct list_head *head = &sdp->sd_log_flush_list;
         struct gfs2_log_buf *lb;
         struct buffer_head *bh;
+        int flushcount = 0;
 
         while (!list_empty(head)) {
                 lb = list_entry(head->next, struct gfs2_log_buf, lb_list);
@@ -533,9 +597,20 @@ static void log_flush_commit(struct gfs2_sbd *sdp)
                 } else
                         brelse(bh);
                 kfree(lb);
+                flushcount++;
         }
 
-        log_write_header(sdp, 0, 0);
+        /* If nothing was journaled, the header is unplanned and unwanted. */
+        if (flushcount) {
+                log_write_header(sdp, 0, 0);
+        } else {
+                unsigned int tail;
+                tail = current_tail(sdp);
+
+                gfs2_ail1_empty(sdp, 0);
+                if (sdp->sd_log_tail != tail)
+                        log_pull_tail(sdp, tail);
+        }
 }
 
 /**
@@ -565,7 +640,10 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
         INIT_LIST_HEAD(&ai->ai_ail1_list);
         INIT_LIST_HEAD(&ai->ai_ail2_list);
 
-        gfs2_assert_withdraw(sdp, sdp->sd_log_num_buf == sdp->sd_log_commited_buf);
+        gfs2_assert_withdraw(sdp,
+                             sdp->sd_log_num_buf + sdp->sd_log_num_jdata ==
+                             sdp->sd_log_commited_buf +
+                             sdp->sd_log_commited_databuf);
         gfs2_assert_withdraw(sdp,
                         sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);
 
@@ -576,16 +654,19 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
         lops_before_commit(sdp);
         if (!list_empty(&sdp->sd_log_flush_list))
                 log_flush_commit(sdp);
-        else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle)
+        else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle){
+                gfs2_log_lock(sdp);
+                sdp->sd_log_blks_free--; /* Adjust for unreserved buffer */
+                gfs2_log_unlock(sdp);
                 log_write_header(sdp, 0, PULL);
+        }
         lops_after_commit(sdp, ai);
 
         gfs2_log_lock(sdp);
         sdp->sd_log_head = sdp->sd_log_flush_head;
-        sdp->sd_log_blks_free -= sdp->sd_log_num_hdrs;
         sdp->sd_log_blks_reserved = 0;
         sdp->sd_log_commited_buf = 0;
-        sdp->sd_log_num_hdrs = 0;
+        sdp->sd_log_commited_databuf = 0;
         sdp->sd_log_commited_revoke = 0;
 
         if (!list_empty(&ai->ai_ail1_list)) {
@@ -602,32 +683,26 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
 
 static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 {
-        unsigned int reserved = 0;
+        unsigned int reserved;
         unsigned int old;
 
         gfs2_log_lock(sdp);
 
         sdp->sd_log_commited_buf += tr->tr_num_buf_new - tr->tr_num_buf_rm;
-        gfs2_assert_withdraw(sdp, ((int)sdp->sd_log_commited_buf) >= 0);
+        sdp->sd_log_commited_databuf += tr->tr_num_databuf_new -
+                tr->tr_num_databuf_rm;
+        gfs2_assert_withdraw(sdp, (((int)sdp->sd_log_commited_buf) >= 0) ||
+                             (((int)sdp->sd_log_commited_databuf) >= 0));
         sdp->sd_log_commited_revoke += tr->tr_num_revoke - tr->tr_num_revoke_rm;
         gfs2_assert_withdraw(sdp, ((int)sdp->sd_log_commited_revoke) >= 0);
-
-        if (sdp->sd_log_commited_buf)
-                reserved += sdp->sd_log_commited_buf;
-        if (sdp->sd_log_commited_revoke)
-                reserved += gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
-                                            sizeof(u64));
-        if (reserved)
-                reserved++;
-
+        reserved = calc_reserved(sdp);
         old = sdp->sd_log_blks_free;
         sdp->sd_log_blks_free += tr->tr_reserved -
                                  (reserved - sdp->sd_log_blks_reserved);
 
         gfs2_assert_withdraw(sdp, sdp->sd_log_blks_free >= old);
-        gfs2_assert_withdraw(sdp,
-                             sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks +
-                             sdp->sd_log_num_hdrs);
+        gfs2_assert_withdraw(sdp, sdp->sd_log_blks_free <=
+                             sdp->sd_jdesc->jd_blocks);
 
         sdp->sd_log_blks_reserved = reserved;
 
@@ -673,13 +748,13 @@ void gfs2_log_shutdown(struct gfs2_sbd *sdp)
         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_rg);
         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_databuf);
-        gfs2_assert_withdraw(sdp, !sdp->sd_log_num_hdrs);
         gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail1_list));
 
         sdp->sd_log_flush_head = sdp->sd_log_head;
         sdp->sd_log_flush_wrapped = 0;
 
-        log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT, 0);
+        log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT,
+                         (sdp->sd_log_tail == current_tail(sdp)) ? 0 : PULL);
 
         gfs2_assert_warn(sdp, sdp->sd_log_blks_free == sdp->sd_jdesc->jd_blocks);
         gfs2_assert_warn(sdp, sdp->sd_log_head == sdp->sd_log_tail);