diff options
Diffstat (limited to 'fs/dcache.c')
| -rw-r--r-- | fs/dcache.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index e7a1a99b746..46fc7820678 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1174,6 +1174,41 @@ struct dentry * d_alloc_anon(struct inode *inode) return res; } +/** + * d_obtain_alias - find or allocate a dentry for a given inode + * @inode: inode to allocate the dentry for + * + * Obtain a dentry for an inode resulting from NFS filehandle conversion or + * similar open by handle operations. The returned dentry may be anonymous, + * or may have a full name (if the inode was already in the cache). + * + * When called on a directory inode, we must ensure that the inode only ever + * has one dentry. If a dentry is found, that is returned instead of + * allocating a new one. + * + * On successful return, the reference to the inode has been transferred + * to the dentry. If %NULL is returned (indicating kmalloc failure), + * the reference on the inode has been released. To make it easier + * to use in export operations a NULL or IS_ERR inode may be passed in + * and will be casted to the corresponding NULL or IS_ERR dentry. + */ +struct dentry *d_obtain_alias(struct inode *inode) +{ + struct dentry *dentry; + + if (!inode) + return NULL; + if (IS_ERR(inode)) + return ERR_CAST(inode); + + dentry = d_alloc_anon(inode); + if (!dentry) { + iput(inode); + dentry = ERR_PTR(-ENOMEM); + } + return dentry; +} +EXPORT_SYMBOL_GPL(d_obtain_alias); /** * d_splice_alias - splice a disconnected dentry into the tree if one exists |