f2fs: call radix_tree_preload before radix_tree_insert

This patch tries to fix:

 BUG: using smp_processor_id() in preemptible [00000000] code: f2fs_gc-254:0/384
  (radix_tree_node_alloc+0x14/0x74) from [<c033d8a0>] (radix_tree_insert+0x110/0x200)
  (radix_tree_insert+0x110/0x200) from [<c02e8264>] (gc_data_segment+0x340/0x52c)
  (gc_data_segment+0x340/0x52c) from [<c02e8658>] (f2fs_gc+0x208/0x400)
  (f2fs_gc+0x208/0x400) from [<c02e8a98>] (gc_thread_func+0x248/0x28c)
  (gc_thread_func+0x248/0x28c) from [<c0139944>] (kthread+0xa0/0xac)
  (kthread+0xa0/0xac) from [<c0105ef8>] (ret_from_fork+0x14/0x3c)

The reason is that f2fs calls radix_tree_insert under enabled preemption.
So, before calling it, we need to call radix_tree_preload.

Otherwise, we should use _GFP_WAIT for the radix tree, and use mutex or
semaphore to cover the radix tree operations.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 20a917b..6a81b73 100644 (file)
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -304,6 +304,11 @@ static void __add_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int type)
        struct inode_management *im = &sbi->im[type];
        struct ino_entry *e;
 retry:
+       if (radix_tree_preload(GFP_NOFS)) {
+               cond_resched();
+               goto retry;
+       }
+
        spin_lock(&im->ino_lock);
 
        e = radix_tree_lookup(&im->ino_root, ino);
@@ -311,11 +316,13 @@ retry:
                e = kmem_cache_alloc(ino_entry_slab, GFP_ATOMIC);
                if (!e) {
                        spin_unlock(&im->ino_lock);
+                       radix_tree_preload_end();
                        goto retry;
                }
                if (radix_tree_insert(&im->ino_root, ino, e)) {
                        spin_unlock(&im->ino_lock);
                        kmem_cache_free(ino_entry_slab, e);
+                       radix_tree_preload_end();
                        goto retry;
                }
                memset(e, 0, sizeof(struct ino_entry));
@@ -326,6 +333,7 @@ retry:
                        im->ino_num++;
        }
        spin_unlock(&im->ino_lock);
+       radix_tree_preload_end();
 }
 
 static void __remove_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int type)

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index a1af74f..2c58c58 100644 (file)
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -351,7 +351,6 @@ static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
 {
        struct inode_entry *new_ie;
-       int ret;
 
        if (inode == find_gc_inode(gc_list, inode->i_ino)) {
                iput(inode);
@@ -361,8 +360,7 @@ retry:
        new_ie = f2fs_kmem_cache_alloc(winode_slab, GFP_NOFS);
        new_ie->inode = inode;
 
-       ret = radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
-       if (ret) {
+       if (radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie)) {
                kmem_cache_free(winode_slab, new_ie);
                goto retry;
        }
@@ -703,7 +701,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi)
        struct cp_control cpc;
        struct gc_inode_list gc_list = {
                .ilist = LIST_HEAD_INIT(gc_list.ilist),
-               .iroot = RADIX_TREE_INIT(GFP_ATOMIC),
+               .iroot = RADIX_TREE_INIT(GFP_NOFS),
        };
 
        cpc.reason = test_opt(sbi, FASTBOOT) ? CP_UMOUNT : CP_SYNC;

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index b47555f..8de4f55 100644 (file)
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1447,15 +1447,22 @@ static int add_free_nid(struct f2fs_sb_info *sbi, nid_t nid, bool build)
        i->nid = nid;
        i->state = NID_NEW;
 
+       if (radix_tree_preload(GFP_NOFS)) {
+               kmem_cache_free(free_nid_slab, i);
+               return 0;
+       }
+
        spin_lock(&nm_i->free_nid_list_lock);
        if (radix_tree_insert(&nm_i->free_nid_root, i->nid, i)) {
                spin_unlock(&nm_i->free_nid_list_lock);
+               radix_tree_preload_end();
                kmem_cache_free(free_nid_slab, i);
                return 0;
        }
        list_add_tail(&i->list, &nm_i->free_nid_list);
        nm_i->fcnt++;
        spin_unlock(&nm_i->free_nid_list_lock);
+       radix_tree_preload_end();
        return 1;
 }
 
@@ -1994,8 +2001,8 @@ static int init_node_manager(struct f2fs_sb_info *sbi)
 
        INIT_RADIX_TREE(&nm_i->free_nid_root, GFP_ATOMIC);
        INIT_LIST_HEAD(&nm_i->free_nid_list);
-       INIT_RADIX_TREE(&nm_i->nat_root, GFP_ATOMIC);
-       INIT_RADIX_TREE(&nm_i->nat_set_root, GFP_ATOMIC);
+       INIT_RADIX_TREE(&nm_i->nat_root, GFP_NOIO);
+       INIT_RADIX_TREE(&nm_i->nat_set_root, GFP_NOIO);
        INIT_LIST_HEAD(&nm_i->nat_entries);
 
        mutex_init(&nm_i->build_lock);