Btrfs: use dget_parent where we can UPDATED

There are lots of places where we do dentry->d_parent->d_inode without holding
the dentry->d_lock.  This could cause problems with rename.  So instead we need
to use dget_parent() and hold the reference to the parent as long as we are
going to use it's inode and then dput it at the end.

Signed-off-by: Josef Bacik <josef@redhat.com>
Cc: raven@themaw.net
Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index fc22f556aa24aae0a30d694f07a80d123cac51e8..c0faf47d0cd94a22d6ff3a55d14fb85e293e53d9 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4811,10 +4811,12 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
        if (err) {
                drop_inode = 1;
        } else {
+               struct dentry *parent = dget_parent(dentry);
                btrfs_update_inode_block_group(trans, dir);
                err = btrfs_update_inode(trans, root, inode);
                BUG_ON(err);
-               btrfs_log_new_name(trans, inode, NULL, dentry->d_parent);
+               btrfs_log_new_name(trans, inode, NULL, parent);
+               dput(parent);
        }
 
        nr = trans->blocks_used;
@@ -6768,8 +6770,9 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
        BUG_ON(ret);
 
        if (old_inode->i_ino != BTRFS_FIRST_FREE_OBJECTID) {
-               btrfs_log_new_name(trans, old_inode, old_dir,
-                                  new_dentry->d_parent);
+               struct dentry *parent = dget_parent(new_dentry);
+               btrfs_log_new_name(trans, old_inode, old_dir, parent);
+               dput(parent);
                btrfs_end_log_trans(root);
        }
 out_fail:

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 6b4bfa72bf8d89da747bf84be491e8841f87cb91..f1c9bb4079ed8b3aaf2a01bb5211923f8e231986 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -233,7 +233,8 @@ static noinline int create_subvol(struct btrfs_root *root,
        struct btrfs_inode_item *inode_item;
        struct extent_buffer *leaf;
        struct btrfs_root *new_root;
-       struct inode *dir = dentry->d_parent->d_inode;
+       struct dentry *parent = dget_parent(dentry);
+       struct inode *dir;
        int ret;
        int err;
        u64 objectid;
@@ -242,8 +243,13 @@ static noinline int create_subvol(struct btrfs_root *root,
 
        ret = btrfs_find_free_objectid(NULL, root->fs_info->tree_root,
                                       0, &objectid);
-       if (ret)
+       if (ret) {
+               dput(parent);
                return ret;
+       }
+
+       dir = parent->d_inode;
+
        /*
         * 1 - inode item
         * 2 - refs
@@ -251,8 +257,10 @@ static noinline int create_subvol(struct btrfs_root *root,
         * 2 - dir items
         */
        trans = btrfs_start_transaction(root, 6);
-       if (IS_ERR(trans))
+       if (IS_ERR(trans)) {
+               dput(parent);
                return PTR_ERR(trans);
+       }
 
        leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
                                      0, objectid, NULL, 0, 0, 0);
@@ -339,6 +347,7 @@ static noinline int create_subvol(struct btrfs_root *root,
 
        d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry));
 fail:
+       dput(parent);
        if (async_transid) {
                *async_transid = trans->transid;
                err = btrfs_commit_transaction_async(trans, root, 1);
@@ -354,6 +363,7 @@ static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
                           char *name, int namelen, u64 *async_transid)
 {
        struct inode *inode;
+       struct dentry *parent;
        struct btrfs_pending_snapshot *pending_snapshot;
        struct btrfs_trans_handle *trans;
        int ret;
@@ -396,7 +406,9 @@ static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
 
        btrfs_orphan_cleanup(pending_snapshot->snap);
 
-       inode = btrfs_lookup_dentry(dentry->d_parent->d_inode, dentry);
+       parent = dget_parent(dentry);
+       inode = btrfs_lookup_dentry(parent->d_inode, dentry);
+       dput(parent);
        if (IS_ERR(inode)) {
                ret = PTR_ERR(inode);
                goto fail;

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 1fffbc017bdfe0451cc2e67ccf5fd85623a12aee..f50e931fc217b978b0bcf1fb54f0d661d3b53562 100644 (file)
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -902,6 +902,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
        struct btrfs_root *root = pending->root;
        struct btrfs_root *parent_root;
        struct inode *parent_inode;
+       struct dentry *parent;
        struct dentry *dentry;
        struct extent_buffer *tmp;
        struct extent_buffer *old;
@@ -941,7 +942,8 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
        trans->block_rsv = &pending->block_rsv;
 
        dentry = pending->dentry;
-       parent_inode = dentry->d_parent->d_inode;
+       parent = dget_parent(dentry);
+       parent_inode = parent->d_inode;
        parent_root = BTRFS_I(parent_inode)->root;
        record_root_in_trans(trans, parent_root);
 
@@ -989,6 +991,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
                                 parent_inode->i_ino, index,
                                 dentry->d_name.name, dentry->d_name.len);
        BUG_ON(ret);
+       dput(parent);
 
        key.offset = (u64)-1;
        pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index a29f19384a27bc91526d46fb3cbefdbe2bd8a5ce..054744ac571907e4c76a5e35f35b8baba24152e2 100644 (file)
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2869,6 +2869,7 @@ static noinline int check_parent_dirs_for_sync(struct btrfs_trans_handle *trans,
 {
        int ret = 0;
        struct btrfs_root *root;
+       struct dentry *old_parent = NULL;
 
        /*
         * for regular files, if its inode is already on disk, we don't
@@ -2910,10 +2911,13 @@ static noinline int check_parent_dirs_for_sync(struct btrfs_trans_handle *trans,
                if (IS_ROOT(parent))
                        break;
 
-               parent = parent->d_parent;
+               parent = dget_parent(parent);
+               dput(old_parent);
+               old_parent = parent;
                inode = parent->d_inode;
 
        }
+       dput(old_parent);
 out:
        return ret;
 }
@@ -2945,6 +2949,7 @@ int btrfs_log_inode_parent(struct btrfs_trans_handle *trans,
 {
        int inode_only = exists_only ? LOG_INODE_EXISTS : LOG_INODE_ALL;
        struct super_block *sb;
+       struct dentry *old_parent = NULL;
        int ret = 0;
        u64 last_committed = root->fs_info->last_trans_committed;
 
@@ -3016,10 +3021,13 @@ int btrfs_log_inode_parent(struct btrfs_trans_handle *trans,
                if (IS_ROOT(parent))
                        break;
 
-               parent = parent->d_parent;
+               parent = dget_parent(parent);
+               dput(old_parent);
+               old_parent = parent;
        }
        ret = 0;
 end_trans:
+       dput(old_parent);
        if (ret < 0) {
                BUG_ON(ret != -ENOSPC);
                root->fs_info->last_trans_log_full_commit = trans->transid;
@@ -3039,8 +3047,13 @@ end_no_trans:
 int btrfs_log_dentry_safe(struct btrfs_trans_handle *trans,
                          struct btrfs_root *root, struct dentry *dentry)
 {
-       return btrfs_log_inode_parent(trans, root, dentry->d_inode,
-                                     dentry->d_parent, 0);
+       struct dentry *parent = dget_parent(dentry);
+       int ret;
+
+       ret = btrfs_log_inode_parent(trans, root, dentry->d_inode, parent, 0);
+       dput(parent);
+
+       return ret;
 }
 
 /*