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Commit 3b96362c authored by Sven Wegener's avatar Sven Wegener Committed by Chris Mason
Browse files

Btrfs: Invalidate dcache entry after creating snapshot and 



We need to invalidate an existing dcache entry after creating a new
snapshot or subvolume, because a negative dache entry will stop us from
accessing the new snapshot or subvolume.

---
  ctree.h       |   23 +++++++++++++++++++++++
  inode.c       |    4 ++++
  transaction.c |    4 ++++
  3 files changed, 31 insertions(+)

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 48ec2cf8

fs/btrfs/ctree.h

+3 −0
Original line number Diff line number Diff line
@@ -1544,6 +1544,9 @@ int btrfs_csum_truncate(struct btrfs_trans_handle *trans, 
			struct btrfs_root *root, struct btrfs_path *path,

			u64 isize);

/* inode.c */

void btrfs_invalidate_dcache_root(struct btrfs_root *root, char *name,

				  int namelen);



int btrfs_merge_bio_hook(struct page *page, unsigned long offset,

			 size_t size, struct bio *bio);

fs/btrfs/inode.c

+29 −0
Original line number Diff line number Diff line
@@ -2642,6 +2642,31 @@ static void btrfs_truncate(struct inode *inode) 
	btrfs_throttle(root);

}



/*

 * Invalidate a single dcache entry at the root of the filesystem.

 * Needed after creation of snapshot or subvolume.

 */

void btrfs_invalidate_dcache_root(struct btrfs_root *root, char *name,

				  int namelen)

{

	struct dentry *alias, *entry;

	struct qstr qstr;



	alias = d_find_alias(root->fs_info->sb->s_root->d_inode);

	if (alias) {

		qstr.name = name;

		qstr.len = namelen;

		/* change me if btrfs ever gets a d_hash operation */

		qstr.hash = full_name_hash(qstr.name, qstr.len);

		entry = d_lookup(alias, &qstr);

		dput(alias);

		if (entry) {

			d_invalidate(entry);

			dput(entry);

		}

	}

}



static int noinline create_subvol(struct btrfs_root *root, char *name,

				  int namelen)

{
@@ -2761,6 +2786,10 @@ static int noinline create_subvol(struct btrfs_root *root, char *name, 
	ret = btrfs_update_inode(trans, new_root, inode);

	if (ret)

		goto fail;



	/* Invalidate existing dcache entry for new subvolume. */

	btrfs_invalidate_dcache_root(root, name, namelen);



fail:

	nr = trans->blocks_used;

	err = btrfs_commit_transaction(trans, new_root);

fs/btrfs/transaction.c

+7 −1
Original line number Diff line number Diff line
@@ -560,6 +560,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, 
	struct btrfs_root *root = pending->root;

	struct extent_buffer *tmp;

	int ret;

	int namelen;

	u64 objectid;



	new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
@@ -595,8 +596,9 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, 
	 * insert the directory item

	 */

	key.offset = (u64)-1;

	namelen = strlen(pending->name);

	ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,

				    pending->name, strlen(pending->name),

				    pending->name, namelen,

				    root->fs_info->sb->s_root->d_inode->i_ino,

				    &key, BTRFS_FT_DIR);
@@ -606,6 +608,10 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, 
	ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,

			     pending->name, strlen(pending->name), objectid,

			     root->fs_info->sb->s_root->d_inode->i_ino);



	/* Invalidate existing dcache entry for new snapshot. */

	btrfs_invalidate_dcache_root(root, pending->name, namelen);



fail:

	kfree(new_root_item);

	return ret;