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@@ -364,7 +364,6 @@ struct inode_operations {
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int (*atomic_open)(struct inode *, struct dentry *, struct file *,
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unsigned open_flag, umode_t create_mode, int *opened);
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int (*tmpfile) (struct inode *, struct dentry *, umode_t);
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- int (*dentry_open)(struct dentry *, struct file *, const struct cred *);
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};
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Again, all methods are called without any locks being held, unless
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@@ -696,13 +695,6 @@ struct address_space_operations {
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but instead uses bmap to find out where the blocks in the file
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are and uses those addresses directly.
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- dentry_open: *WARNING: probably going away soon, do not use!* This is an
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- alternative to f_op->open(), the difference is that this method may open
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- a file not necessarily originating from the same filesystem as the one
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- i_op->open() was called on. It may be useful for stacking filesystems
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- which want to allow native I/O directly on underlying files.
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-
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-
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invalidatepage: If a page has PagePrivate set, then invalidatepage
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will be called when part or all of the page is to be removed
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from the address space. This generally corresponds to either a
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@@ -938,6 +930,8 @@ struct dentry_operations {
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char *(*d_dname)(struct dentry *, char *, int);
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struct vfsmount *(*d_automount)(struct path *);
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int (*d_manage)(struct dentry *, bool);
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+ struct dentry *(*d_real)(struct dentry *, const struct inode *,
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+ unsigned int);
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};
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d_revalidate: called when the VFS needs to revalidate a dentry. This
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@@ -1022,6 +1016,14 @@ struct dentry_operations {
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at the end of the buffer, and returns a pointer to the first char.
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dynamic_dname() helper function is provided to take care of this.
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+ Example :
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+
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+ static char *pipefs_dname(struct dentry *dent, char *buffer, int buflen)
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+ {
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+ return dynamic_dname(dentry, buffer, buflen, "pipe:[%lu]",
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+ dentry->d_inode->i_ino);
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+ }
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+
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d_automount: called when an automount dentry is to be traversed (optional).
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This should create a new VFS mount record and return the record to the
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caller. The caller is supplied with a path parameter giving the
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@@ -1060,13 +1062,23 @@ struct dentry_operations {
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This function is only used if DCACHE_MANAGE_TRANSIT is set on the
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dentry being transited from.
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-Example :
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+ d_real: overlay/union type filesystems implement this method to return one of
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+ the underlying dentries hidden by the overlay. It is used in three
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+ different modes:
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-static char *pipefs_dname(struct dentry *dent, char *buffer, int buflen)
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-{
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- return dynamic_dname(dentry, buffer, buflen, "pipe:[%lu]",
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- dentry->d_inode->i_ino);
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-}
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+ Called from open it may need to copy-up the file depending on the
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+ supplied open flags. This mode is selected with a non-zero flags
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+ argument. In this mode the d_real method can return an error.
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+
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+ Called from file_dentry() it returns the real dentry matching the inode
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+ argument. The real dentry may be from a lower layer already copied up,
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+ but still referenced from the file. This mode is selected with a
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+ non-NULL inode argument. This will always succeed.
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+
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+ With NULL inode and zero flags the topmost real underlying dentry is
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+ returned. This will always succeed.
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+
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+ This method is never called with both non-NULL inode and non-zero flags.
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Each dentry has a pointer to its parent dentry, as well as a hash list
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of child dentries. Child dentries are basically like files in a
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Miklos Szeredi