X-Git-Url: https://git.camperquake.de/gitweb.cgi?a=blobdiff_plain;f=module%2Fzfs%2Fzfs_znode.c;h=1fe88499b555ffe16712e75a8bbd7cae3d0e78a4;hb=1d82906dea5eb698a854d992e445e794fb5a0880;hp=0bb9c09e57ad9fa445dcb995550326783f57df64;hpb=5484965ab650a56871a62a3373859a7a36ddafcb;p=zfs.git

diff --git a/module/zfs/zfs_znode.c b/module/zfs/zfs_znode.c
index 0bb9c09..1fe8849 100644
--- a/module/zfs/zfs_znode.c
+++ b/module/zfs/zfs_znode.c
@@ -174,7 +174,7 @@ zfs_create_share_dir(zfs_sb_t *zsb, dmu_tx_t *tx)
 	vattr.va_uid = crgetuid(kcred);
 	vattr.va_gid = crgetgid(kcred);
 
-	sharezp = kmem_cache_alloc(znode_cache, KM_SLEEP);
+	sharezp = kmem_cache_alloc(znode_cache, KM_PUSHPAGE);
 	sharezp->z_moved = 0;
 	sharezp->z_unlinked = 0;
 	sharezp->z_atime_dirty = 0;
@@ -248,7 +248,7 @@ zfs_inode_alloc(struct super_block *sb, struct inode **ip)
 {
 	znode_t *zp;
 
-	zp = kmem_cache_alloc(znode_cache, KM_SLEEP);
+	zp = kmem_cache_alloc(znode_cache, KM_PUSHPAGE);
 	*ip = ZTOI(zp);
 
 	return (0);
@@ -347,6 +347,7 @@ zfs_znode_alloc(zfs_sb_t *zsb, dmu_buf_t *db, int blksz,
 	zp->z_blksz = blksz;
 	zp->z_seq = 0x7A4653;
 	zp->z_sync_cnt = 0;
+	zp->z_is_zvol = 0;
 
 	zfs_znode_sa_init(zsb, zp, db, obj_type, hdl);
 
@@ -979,13 +980,24 @@ zfs_zinactive(znode_t *zp)
 {
 	zfs_sb_t *zsb = ZTOZSB(zp);
 	uint64_t z_id = zp->z_id;
+	boolean_t drop_mutex = 0;
 
 	ASSERT(zp->z_sa_hdl);
 
 	/*
-	 * Don't allow a zfs_zget() while were trying to release this znode
+	 * Don't allow a zfs_zget() while were trying to release this znode.
+	 *
+	 * Linux allows direct memory reclaim which means that any KM_SLEEP
+	 * allocation may trigger inode eviction.  This can lead to a deadlock
+	 * through the ->shrink_icache_memory()->evict()->zfs_inactive()->
+	 * zfs_zinactive() call path.  To avoid this deadlock the process
+	 * must not reacquire the mutex when it is already holding it.
 	 */
-	ZFS_OBJ_HOLD_ENTER(zsb, z_id);
+	if (!ZFS_OBJ_HOLD_OWNED(zsb, z_id)) {
+		ZFS_OBJ_HOLD_ENTER(zsb, z_id);
+		drop_mutex = 1;
+	}
+
 	mutex_enter(&zp->z_lock);
 
 	/*
@@ -994,14 +1006,19 @@ zfs_zinactive(znode_t *zp)
 	 */
 	if (zp->z_unlinked) {
 		mutex_exit(&zp->z_lock);
-		ZFS_OBJ_HOLD_EXIT(zsb, z_id);
+
+		if (drop_mutex)
+			ZFS_OBJ_HOLD_EXIT(zsb, z_id);
+
 		zfs_rmnode(zp);
 		return;
 	}
 
 	mutex_exit(&zp->z_lock);
 	zfs_znode_dmu_fini(zp);
-	ZFS_OBJ_HOLD_EXIT(zsb, z_id);
+
+	if (drop_mutex)
+		ZFS_OBJ_HOLD_EXIT(zsb, z_id);
 }
 
 void