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Btrfs: use dget_parent where we can UPDATED

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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>
This commit is contained in:
Josef Bacik
2010-11-20 09:48:00 +00:00
committed by Chris Mason
parent 7619585390
commit 6a91221304
4 changed files with 43 additions and 12 deletions
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20
fs/btrfs/ioctl.c
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@@ -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;