JFS: Protect active_ag with a spinlock

Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>

fs/jfs/file.c

@@ -65,11 +65,13 @@ static int jfs_open(struct inode *inode, struct file *file)
 	if (S_ISREG(inode->i_mode) && file->f_mode & FMODE_WRITE &&
 	    (inode->i_size == 0)) {
 		struct jfs_inode_info *ji = JFS_IP(inode);
+		spin_lock_irq(&ji->ag_lock);
 		if (ji->active_ag == -1) {
 			ji->active_ag = ji->agno;
 			atomic_inc(
 			    &JFS_SBI(inode->i_sb)->bmap->db_active[ji->agno]);
 		}
+		spin_unlock_irq(&ji->ag_lock);
 	}
 
 	return 0;
@@ -78,11 +80,13 @@ static int jfs_release(struct inode *inode, struct file *file)
 {
 	struct jfs_inode_info *ji = JFS_IP(inode);
 
+	spin_lock_irq(&ji->ag_lock);
 	if (ji->active_ag != -1) {
 		struct bmap *bmap = JFS_SBI(inode->i_sb)->bmap;
 		atomic_dec(&bmap->db_active[ji->active_ag]);
 		ji->active_ag = -1;
 	}
+	spin_unlock_irq(&ji->ag_lock);
 
 	return 0;
 }

fs/jfs/jfs_extent.c

@@ -553,6 +553,7 @@ extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
 
 	if (S_ISREG(ip->i_mode) && (ji->fileset == FILESYSTEM_I)) {
 		ag = BLKTOAG(daddr, sbi);
+		spin_lock_irq(&ji->ag_lock);
 		if (ji->active_ag == -1) {
 			atomic_inc(&bmp->db_active[ag]);
 			ji->active_ag = ag;
@@ -561,6 +562,7 @@ extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
 			atomic_inc(&bmp->db_active[ag]);
 			ji->active_ag = ag;
 		}
+		spin_unlock_irq(&ji->ag_lock);
 	}
 
 	return (0);

fs/jfs/jfs_incore.h

@@ -53,6 +53,7 @@ struct jfs_inode_info {
 	lid_t	blid;		/* lid of pseudo buffer?	*/
 	lid_t	atlhead;	/* anonymous tlock list head	*/
 	lid_t	atltail;	/* anonymous tlock list tail	*/
+	spinlock_t ag_lock;	/* protects active_ag		*/
 	struct list_head anon_inode_list; /* inodes having anonymous txns */
 	/*
 	 * rdwrlock serializes xtree between reads & writes and synchronizes

fs/jfs/super.c

@@ -141,10 +141,13 @@ static void jfs_destroy_inode(struct inode *inode)
 {
 	struct jfs_inode_info *ji = JFS_IP(inode);
 
+	spin_lock_irq(&ji->ag_lock);
 	if (ji->active_ag != -1) {
 		struct bmap *bmap = JFS_SBI(inode->i_sb)->bmap;
 		atomic_dec(&bmap->db_active[ji->active_ag]);
+		ji->active_ag = -1;
 	}
+	spin_unlock_irq(&ji->ag_lock);
 
 #ifdef CONFIG_JFS_POSIX_ACL
 	if (ji->i_acl != JFS_ACL_NOT_CACHED) {
@@ -559,6 +562,7 @@ static void init_once(void *foo, kmem_cache_t * cachep, unsigned long flags)
 		init_rwsem(&jfs_ip->rdwrlock);
 		init_MUTEX(&jfs_ip->commit_sem);
 		init_rwsem(&jfs_ip->xattr_sem);
+		spin_lock_init(&jfs_ip->ag_lock);
 		jfs_ip->active_ag = -1;
 #ifdef CONFIG_JFS_POSIX_ACL
 		jfs_ip->i_acl = JFS_ACL_NOT_CACHED;