SysTutorials Posts

d_rehash – add an entry back to the hash Synopsis void d_rehash(struct dentry *entry); Arguments entry dentry to add to the hash Description Adds a dentry to the hash according to its name. Copyright

d_really_is_positive – Determine if a dentry is really positive (ignoring fallthroughs) Synopsis bool d_really_is_positive(const struct dentry * dentry); Arguments dentry The dentry in question Description Returns true if the dentry represents a name that maps to an inode (ie. ->d_inode is not NULL). The dentry might still represent a whiteout if that is represented on medium as…

d_really_is_negative – Determine if a dentry is really negative (ignoring fallthroughs) Synopsis bool d_really_is_negative(const struct dentry * dentry); Arguments dentry The dentry in question Description Returns true if the dentry represents either an absent name or a name that doesn’t map to an inode (ie. ->d_inode is NULL). The dentry could represent a true miss, a whiteout…

d_real_inode – Return the real inode Synopsis struct inode *d_real_inode(const struct dentry *dentry); Arguments dentry The dentry to query Description If dentry is on an union/overlay, then return the underlying, real inode. Otherwise return d_inode. Copyright

d_real – Return the real dentry Synopsis struct dentry *d_real(struct dentry *dentry, const struct inode *inode, unsigned int flags); Arguments dentry the dentry to query inode inode to select the dentry from multiple layers (can be NULL) flags open flags to control copy-up behavior Description If dentry is on an union/overlay, then return the underlying,…

d_path – return the path of a dentry Synopsis char *d_path(const struct path *path, char *buf, int buflen); Arguments path path to report buf buffer to return value in buflen buffer length Description Convert a dentry into an ASCII path name. If the entry has been deleted the string ” (deleted)” is appended. Note that…

d_obtain_root – find or allocate a dentry for a given inode Synopsis struct dentry *d_obtain_root(struct inode *inode); Arguments inode inode to allocate the dentry for Description Obtain an IS_ROOT dentry for the root of a filesystem. We must ensure that directory inodes only ever have one dentry. If a dentry is found, that is returned…

d_obtain_alias – find or allocate a DISCONNECTED dentry for a given inode Synopsis struct dentry *d_obtain_alias(struct inode *inode); Arguments inode inode to allocate the dentry for Description 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…

d_lookup – search for a dentry Synopsis struct dentry *d_lookup(const struct dentry *parent, const struct qstr *name); Arguments parent parent dentry name qstr of name we wish to find Return dentry, or NULL d_lookup searches the children of the parent dentry for the name in question. If the dentry is found its reference count is…

d_invalidate – detach submounts, prune dcache, and drop Synopsis void d_invalidate(struct dentry *dentry); Arguments dentry dentry to invalidate (aka detach, prune and drop) Description no dcache lock. The final d_drop is done as an atomic operation relative to rename_lock ensuring there are no races with d_set_mounted. This ensures there are no unhashed dentries on the…

d_instantiate_no_diralias – instantiate a non-aliased dentry Synopsis int d_instantiate_no_diralias(struct dentry *entry, struct inode *inode); Arguments entry dentry to complete inode inode to attach to this dentry Description Fill in inode information in the entry. If a directory alias is found, then return an error (and drop inode). Together with d_materialise_unique this guarantees that a directory…

d_instantiate – fill in inode information for a dentry Synopsis void d_instantiate(struct dentry *entry, struct inode *inode); Arguments entry dentry to complete inode inode to attach to this dentry Description Fill in inode information in the entry. This turns negative dentries into productive full members of society. NOTE! This assumes that the inode count has…

d_inode_rcu – Get the actual inode of this dentry with ACCESS_ONCE Synopsis struct inode *d_inode_rcu(const struct dentry *dentry); Arguments dentry The dentry to query Description This is the helper normal filesystems should use to get at their own inodes in their own dentries and ignore the layering superimposed upon them. Copyright

d_inode – Get the actual inode of this dentry Synopsis struct inode *d_inode(const struct dentry *dentry); Arguments dentry The dentry to query Description This is the helper normal filesystems should use to get at their own inodes in their own dentries and ignore the layering superimposed upon them. Copyright

d_hash_and_lookup – hash the qstr then search for a dentry Synopsis struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name); Arguments dir Directory to search in name qstr of name we wish to find Description On lookup failure NULL is returned; on bad name – ERR_PTR(-error) Copyright

d_find_any_alias – find any alias for a given inode Synopsis struct dentry *d_find_any_alias(struct inode *inode); Arguments inode inode to find an alias for Description If any aliases exist for the given inode, take and return a reference for one of them. If no aliases exist, return NULL. Copyright

d_exact_alias – find and hash an exact unhashed alias Synopsis struct dentry *d_exact_alias(struct dentry *entry, struct inode *inode); Arguments entry dentry to add inode The inode to go with this dentry Description If an unhashed dentry with the same name/parent and desired inode already exists, hash and return it. Otherwise, return NULL. Parent directory should…

d_delete – delete a dentry Synopsis void d_delete(struct dentry *dentry); Arguments dentry The dentry to delete Description Turn the dentry into a negative dentry if possible, otherwise remove it from the hash queues so it can be deleted later Copyright

d_backing_inode – Get upper or lower inode we should be using Synopsis struct inode *d_backing_inode(const struct dentry *upper); Arguments upper The upper layer Description This is the helper that should be used to get at the inode that will be used if this dentry were to be opened as a file. The inode may be…

d_backing_dentry – Get upper or lower dentry we should be using Synopsis struct dentry *d_backing_dentry(struct dentry *upper); Arguments upper The upper layer Description This is the helper that should be used to get the dentry of the inode that will be used if this dentry were opened as a file. It may be the upper…