Get rid of BTRFS_I(inode)->index and use local vars instead

rename and link don't always have a lock on the source inode, and
our use of a per-inode index variable was racy.  This changes things to
store the index in a local variable instead.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 34 insertions, 25 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 99121a55ffbe..4d8ffc01931e 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2153,7 +2153,8 @@ out:
         return ret;
 }
 
-static int btrfs_set_inode_index(struct inode *dir, struct inode *inode)
+static int btrfs_set_inode_index(struct inode *dir, struct inode *inode,
+                                 u64 *index)
 {
         int ret = 0;
 
@@ -2163,7 +2164,7 @@ static int btrfs_set_inode_index(struct inode *dir, struct inode *inode)
                         return ret;
         }
 
-        BTRFS_I(inode)->index = BTRFS_I(dir)->index_cnt;
+        *index = BTRFS_I(dir)->index_cnt;
         BTRFS_I(dir)->index_cnt++;
 
         return ret;
@@ -2176,7 +2177,7 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
                                      u64 ref_objectid,
                                      u64 objectid,
                                      struct btrfs_block_group_cache *group,
-                                     int mode)
+                                     int mode, u64 *index)
 {
         struct inode *inode;
         struct btrfs_inode_item *inode_item;
@@ -2198,11 +2199,9 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
                 return ERR_PTR(-ENOMEM);
 
         if (dir) {
-                ret = btrfs_set_inode_index(dir, inode);
+                ret = btrfs_set_inode_index(dir, inode, index);
                 if (ret)
                         return ERR_PTR(ret);
-        } else {
-                BTRFS_I(inode)->index = 0;
         }
         /*
          * index_cnt is ignored for everything but a dir,
@@ -2268,7 +2267,7 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
                              struct btrfs_inode_ref);
         btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
-        btrfs_set_inode_ref_index(path->nodes[0], ref, BTRFS_I(inode)->index);
+        btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
         ptr = (unsigned long)(ref + 1);
         write_extent_buffer(path->nodes[0], name, ptr, name_len);
 
@@ -2296,7 +2295,7 @@ static inline u8 btrfs_inode_type(struct inode *inode)
 
 static int btrfs_add_link(struct btrfs_trans_handle *trans,
                             struct dentry *dentry, struct inode *inode,
-                            int add_backref)
+                            int add_backref, u64 index)
 {
         int ret;
         struct btrfs_key key;
@@ -2311,7 +2310,7 @@ static int btrfs_add_link(struct btrfs_trans_handle *trans,
                                     dentry->d_name.name, dentry->d_name.len,
                                     dentry->d_parent->d_inode->i_ino,
                                     &key, btrfs_inode_type(inode),
-                                    BTRFS_I(inode)->index);
+                                    index);
         if (ret == 0) {
                 if (add_backref) {
                         ret = btrfs_insert_inode_ref(trans, root,
@@ -2319,7 +2318,7 @@ static int btrfs_add_link(struct btrfs_trans_handle *trans,
                                              dentry->d_name.len,
                                              inode->i_ino,
                                              parent_inode->i_ino,
-                                             BTRFS_I(inode)->index);
+                                             index);
                 }
                 btrfs_i_size_write(parent_inode, parent_inode->i_size +
                                    dentry->d_name.len * 2);
@@ -2332,9 +2331,9 @@ static int btrfs_add_link(struct btrfs_trans_handle *trans,
 
 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
                             struct dentry *dentry, struct inode *inode,
-                            int backref)
+                            int backref, u64 index)
 {
-        int err = btrfs_add_link(trans, dentry, inode, backref);
+        int err = btrfs_add_link(trans, dentry, inode, backref, index);
         if (!err) {
                 d_instantiate(dentry, inode);
                 return 0;
@@ -2354,6 +2353,7 @@ static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
         int drop_inode = 0;
         u64 objectid;
         unsigned long nr = 0;
+        u64 index = 0;
 
         if (!new_valid_dev(rdev))
                 return -EINVAL;
@@ -2374,7 +2374,7 @@ static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
                                 dentry->d_name.len,
                                 dentry->d_parent->d_inode->i_ino, objectid,
-                                BTRFS_I(dir)->block_group, mode);
+                                BTRFS_I(dir)->block_group, mode, &index);
         err = PTR_ERR(inode);
         if (IS_ERR(inode))
                 goto out_unlock;
@@ -2386,7 +2386,7 @@ static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
         }
 
         btrfs_set_trans_block_group(trans, inode);
-        err = btrfs_add_nondir(trans, dentry, inode, 0);
+        err = btrfs_add_nondir(trans, dentry, inode, 0, index);
         if (err)
                 drop_inode = 1;
         else {
@@ -2419,6 +2419,7 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
         int drop_inode = 0;
         unsigned long nr = 0;
         u64 objectid;
+        u64 index = 0;
 
         err = btrfs_check_free_space(root, 1, 0);
         if (err)
@@ -2435,7 +2436,8 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
                                 dentry->d_name.len,
                                 dentry->d_parent->d_inode->i_ino,
-                                objectid, BTRFS_I(dir)->block_group, mode);
+                                objectid, BTRFS_I(dir)->block_group, mode,
+                                &index);
         err = PTR_ERR(inode);
         if (IS_ERR(inode))
                 goto out_unlock;
@@ -2447,7 +2449,7 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
         }
 
         btrfs_set_trans_block_group(trans, inode);
-        err = btrfs_add_nondir(trans, dentry, inode, 0);
+        err = btrfs_add_nondir(trans, dentry, inode, 0, index);
         if (err)
                 drop_inode = 1;
         else {
@@ -2489,6 +2491,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
         struct btrfs_trans_handle *trans;
         struct btrfs_root *root = BTRFS_I(dir)->root;
         struct inode *inode = old_dentry->d_inode;
+        u64 index;
         unsigned long nr = 0;
         int err;
         int drop_inode = 0;
@@ -2504,7 +2507,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
         err = btrfs_check_free_space(root, 1, 0);
         if (err)
                 goto fail;
-        err = btrfs_set_inode_index(dir, inode);
+        err = btrfs_set_inode_index(dir, inode, &index);
         if (err)
                 goto fail;
 
@@ -2513,7 +2516,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
         btrfs_set_trans_block_group(trans, dir);
         atomic_inc(&inode->i_count);
 
-        err = btrfs_add_nondir(trans, dentry, inode, 1);
+        err = btrfs_add_nondir(trans, dentry, inode, 1, index);
 
         if (err)
                 drop_inode = 1;
@@ -2544,6 +2547,7 @@ static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
         int err = 0;
         int drop_on_err = 0;
         u64 objectid = 0;
+        u64 index = 0;
         unsigned long nr = 1;
 
         err = btrfs_check_free_space(root, 1, 0);
@@ -2567,7 +2571,8 @@ static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
                                 dentry->d_name.len,
                                 dentry->d_parent->d_inode->i_ino, objectid,
-                                BTRFS_I(dir)->block_group, S_IFDIR | mode);
+                                BTRFS_I(dir)->block_group, S_IFDIR | mode,
+                                &index);
         if (IS_ERR(inode)) {
                 err = PTR_ERR(inode);
                 goto out_fail;
@@ -2588,7 +2593,7 @@ static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
         if (err)
                 goto out_fail;
 
-        err = btrfs_add_link(trans, dentry, inode, 0);
+        err = btrfs_add_link(trans, dentry, inode, 0, index);
         if (err)
                 goto out_fail;
 
@@ -3203,9 +3208,10 @@ int btrfs_create_subvol_root(struct btrfs_root *new_root,
                 struct btrfs_block_group_cache *block_group)
 {
         struct inode *inode;
+        u64 index = 0;
 
         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2, new_dirid,
-                                new_dirid, block_group, S_IFDIR | 0700);
+                                new_dirid, block_group, S_IFDIR | 0700, &index);
         if (IS_ERR(inode))
                 return PTR_ERR(inode);
         inode->i_op = &btrfs_dir_inode_operations;
@@ -3384,6 +3390,7 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
         struct inode *new_inode = new_dentry->d_inode;
         struct inode *old_inode = old_dentry->d_inode;
         struct timespec ctime = CURRENT_TIME;
+        u64 index = 0;
         int ret;
 
         if (S_ISDIR(old_inode->i_mode) && new_inode &&
@@ -3419,11 +3426,11 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
                                 goto out_fail;
                 }
         }
-        ret = btrfs_set_inode_index(new_dir, old_inode);
+        ret = btrfs_set_inode_index(new_dir, old_inode, &index);
         if (ret)
                 goto out_fail;
 
-        ret = btrfs_add_link(trans, new_dentry, old_inode, 1);
+        ret = btrfs_add_link(trans, new_dentry, old_inode, 1, index);
         if (ret)
                 goto out_fail;
 
@@ -3464,6 +3471,7 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
         int err;
         int drop_inode = 0;
         u64 objectid;
+        u64 index = 0 ;
         int name_len;
         int datasize;
         unsigned long ptr;
@@ -3491,7 +3499,8 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
                                 dentry->d_name.len,
                                 dentry->d_parent->d_inode->i_ino, objectid,
-                                BTRFS_I(dir)->block_group, S_IFLNK|S_IRWXUGO);
+                                BTRFS_I(dir)->block_group, S_IFLNK|S_IRWXUGO,
+                                &index);
         err = PTR_ERR(inode);
         if (IS_ERR(inode))
                 goto out_unlock;
@@ -3503,7 +3512,7 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
         }
 
         btrfs_set_trans_block_group(trans, inode);
-        err = btrfs_add_nondir(trans, dentry, inode, 0);
+        err = btrfs_add_nondir(trans, dentry, inode, 0, index);
         if (err)
                 drop_inode = 1;
         else {