GFS2: Fix AIL flush issue during fsync

Unfortunately, it is not enough to just ignore locked buffers during
the AIL flush from fsync. We need to be able to ignore all buffers
which are locked, dirty or pinned at this stage as they might have
been added subsequent to the log flush earlier in the fsync function.

In addition, this means that we no longer need to rely on i_mutex to
keep out writes during fsync, so we can, as a side-effect, remove
that protection too.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Tested-By: Abhijith Das <adas@redhat.com>

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 3467f36621495890d296faf47d5e5ff01838e722..3b65f67bb38e2e27afbb2b6d05443c3da18e37e0 100644 (file)
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -593,16 +593,12 @@ static int gfs2_fsync(struct file *file, loff_t start, loff_t end,
                sync_state &= ~I_DIRTY_SYNC;
 
        if (sync_state) {
-               mutex_lock(&inode->i_mutex);
                ret = sync_inode_metadata(inode, 1);
-               if (ret) {
-                       mutex_unlock(&inode->i_mutex);
+               if (ret)
                        return ret;
-               }
                if (gfs2_is_jdata(ip))
                        filemap_write_and_wait(mapping);
-               gfs2_ail_flush(ip->i_gl);
-               mutex_unlock(&inode->i_mutex);
+               gfs2_ail_flush(ip->i_gl, 1);
        }
 
        if (mapping->nrpages)

diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index 951541b6234c3a22e693b5e9f6e350532d45b662..78418b4fa8571a379d609812ea3c98c029d8184f 100644 (file)
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -42,41 +42,41 @@ static void gfs2_ail_error(struct gfs2_glock *gl, const struct buffer_head *bh)
 /**
  * __gfs2_ail_flush - remove all buffers for a given lock from the AIL
  * @gl: the glock
+ * @fsync: set when called from fsync (not all buffers will be clean)
  *
  * None of the buffers should be dirty, locked, or pinned.
  */
 
-static void __gfs2_ail_flush(struct gfs2_glock *gl, unsigned long b_state)
+static void __gfs2_ail_flush(struct gfs2_glock *gl, bool fsync)
 {
        struct gfs2_sbd *sdp = gl->gl_sbd;
        struct list_head *head = &gl->gl_ail_list;
-       struct gfs2_bufdata *bd;
+       struct gfs2_bufdata *bd, *tmp;
        struct buffer_head *bh;
+       const unsigned long b_state = (1UL << BH_Dirty)|(1UL << BH_Pinned)|(1UL << BH_Lock);
        sector_t blocknr;
 
+       gfs2_log_lock(sdp);
        spin_lock(&sdp->sd_ail_lock);
-       while (!list_empty(head)) {
-               bd = list_entry(head->next, struct gfs2_bufdata,
-                               bd_ail_gl_list);
+       list_for_each_entry_safe(bd, tmp, head, bd_ail_gl_list) {
                bh = bd->bd_bh;
-               blocknr = bh->b_blocknr;
-               if (bh->b_state & b_state)
+               if (bh->b_state & b_state) {
+                       if (fsync)
+                               continue;
                        gfs2_ail_error(gl, bh);
+               }
+               blocknr = bh->b_blocknr;
                bh->b_private = NULL;
                gfs2_remove_from_ail(bd); /* drops ref on bh */
-               spin_unlock(&sdp->sd_ail_lock);
 
                bd->bd_bh = NULL;
                bd->bd_blkno = blocknr;
 
-               gfs2_log_lock(sdp);
                gfs2_trans_add_revoke(sdp, bd);
-               gfs2_log_unlock(sdp);
-
-               spin_lock(&sdp->sd_ail_lock);
        }
-       gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
+       BUG_ON(!fsync && atomic_read(&gl->gl_ail_count));
        spin_unlock(&sdp->sd_ail_lock);
+       gfs2_log_unlock(sdp);
 }
 
 
@@ -99,13 +99,13 @@ static void gfs2_ail_empty_gl(struct gfs2_glock *gl)
        BUG_ON(current->journal_info);
        current->journal_info = &tr;
 
-       __gfs2_ail_flush(gl, (1ul << BH_Dirty)|(1ul << BH_Pinned)|(1ul << BH_Lock));
+       __gfs2_ail_flush(gl, 0);
 
        gfs2_trans_end(sdp);
        gfs2_log_flush(sdp, NULL);
 }
 
-void gfs2_ail_flush(struct gfs2_glock *gl)
+void gfs2_ail_flush(struct gfs2_glock *gl, bool fsync)
 {
        struct gfs2_sbd *sdp = gl->gl_sbd;
        unsigned int revokes = atomic_read(&gl->gl_ail_count);
@@ -117,7 +117,7 @@ void gfs2_ail_flush(struct gfs2_glock *gl)
        ret = gfs2_trans_begin(sdp, 0, revokes);
        if (ret)
                return;
-       __gfs2_ail_flush(gl, (1ul << BH_Dirty)|(1ul << BH_Pinned));
+       __gfs2_ail_flush(gl, fsync);
        gfs2_trans_end(sdp);
        gfs2_log_flush(sdp, NULL);
 }

diff --git a/fs/gfs2/glops.h b/fs/gfs2/glops.h
index 6fce409b5a50669bee82d437edcf4e34976e4a48..bf95a2dc1662e0446a39c20984612c7161615b62 100644 (file)
--- a/fs/gfs2/glops.h
+++ b/fs/gfs2/glops.h
@@ -23,6 +23,6 @@ extern const struct gfs2_glock_operations gfs2_quota_glops;
 extern const struct gfs2_glock_operations gfs2_journal_glops;
 extern const struct gfs2_glock_operations *gfs2_glops_list[];
 
-extern void gfs2_ail_flush(struct gfs2_glock *gl);
+extern void gfs2_ail_flush(struct gfs2_glock *gl, bool fsync);
 
 #endif /* __GLOPS_DOT_H__ */

diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 87e9141a4def28cbd98368309b35e6b7f41e5c3a..71e420989f77c39a45e1f3ff31ac0235f1f62a4d 100644 (file)
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -1533,7 +1533,7 @@ static void gfs2_evict_inode(struct inode *inode)
 out_truncate:
        gfs2_log_flush(sdp, ip->i_gl);
        write_inode_now(inode, 1);
-       gfs2_ail_flush(ip->i_gl);
+       gfs2_ail_flush(ip->i_gl, 0);
 
        /* Case 2 starts here */
        error = gfs2_trans_begin(sdp, 0, sdp->sd_jdesc->jd_blocks);