These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / Documentation / filesystems / vfs.txt

diff --git a/kernel/Documentation/filesystems/vfs.txt b/kernel/Documentation/filesystems/vfs.txt
index 5d833b3..8c6f07a 100644 (file)
--- a/kernel/Documentation/filesystems/vfs.txt
+++ b/kernel/Documentation/filesystems/vfs.txt
@@ -350,8 +350,8 @@ struct inode_operations {
        int (*rename2) (struct inode *, struct dentry *,
                        struct inode *, struct dentry *, unsigned int);
        int (*readlink) (struct dentry *, char __user *,int);
-        void * (*follow_link) (struct dentry *, struct nameidata *);
-        void (*put_link) (struct dentry *, struct nameidata *, void *);
+       const char *(*follow_link) (struct dentry *, void **);
+       void (*put_link) (struct inode *, void *);
        int (*permission) (struct inode *, int);
        int (*get_acl)(struct inode *, int);
        int (*setattr) (struct dentry *, struct iattr *);
@@ -436,16 +436,18 @@ otherwise noted.
 
   follow_link: called by the VFS to follow a symbolic link to the
        inode it points to.  Only required if you want to support
-       symbolic links.  This method returns a void pointer cookie
-       that is passed to put_link().
+       symbolic links.  This method returns the symlink body
+       to traverse (and possibly resets the current position with
+       nd_jump_link()).  If the body won't go away until the inode
+       is gone, nothing else is needed; if it needs to be otherwise
+       pinned, the data needed to release whatever we'd grabbed
+       is to be stored in void * variable passed by address to
+       follow_link() instance.
 
   put_link: called by the VFS to release resources allocated by
-       follow_link().  The cookie returned by follow_link() is passed
-       to this method as the last parameter.  It is used by
-       filesystems such as NFS where page cache is not stable
-       (i.e. page that was installed when the symbolic link walk
-       started might not be in the page cache at the end of the
-       walk).
+       follow_link().  The cookie stored by follow_link() is passed
+       to this method as the last parameter; only called when
+       cookie isn't NULL.
 
   permission: called by the VFS to check for access rights on a POSIX-like
        filesystem.
@@ -767,7 +769,7 @@ struct address_space_operations {
        to stall to allow flushers a chance to complete some IO. Ordinarily
        it can use PageDirty and PageWriteback but some filesystems have
        more complex state (unstable pages in NFS prevent reclaim) or
-       do not set those flags due to locking problems (jbd). This callback
+       do not set those flags due to locking problems. This callback
        allows a filesystem to indicate to the VM if a page should be
        treated as dirty or writeback for the purposes of stalling.
 
@@ -797,7 +799,7 @@ struct file_operations
 ----------------------
 
 This describes how the VFS can manipulate an open file. As of kernel
-3.12, the following members are defined:
+4.1, the following members are defined:
 
 struct file_operations {
        struct module *owner;
@@ -811,8 +813,9 @@ struct file_operations {
        long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
        long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
        int (*mmap) (struct file *, struct vm_area_struct *);
+       int (*mremap)(struct file *, struct vm_area_struct *);
        int (*open) (struct inode *, struct file *);
-       int (*flush) (struct file *);
+       int (*flush) (struct file *, fl_owner_t id);
        int (*release) (struct inode *, struct file *);
        int (*fsync) (struct file *, loff_t, loff_t, int datasync);
        int (*aio_fsync) (struct kiocb *, int datasync);
@@ -822,11 +825,15 @@ struct file_operations {
        unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
        int (*check_flags)(int);
        int (*flock) (struct file *, int, struct file_lock *);
-       ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, size_t, unsigned int);
-       ssize_t (*splice_read)(struct file *, struct pipe_inode_info *, size_t, unsigned int);
-       int (*setlease)(struct file *, long arg, struct file_lock **, void **);
-       long (*fallocate)(struct file *, int mode, loff_t offset, loff_t len);
+       ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
+       ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
+       int (*setlease)(struct file *, long, struct file_lock **, void **);
+       long (*fallocate)(struct file *file, int mode, loff_t offset,
+                         loff_t len);
        void (*show_fdinfo)(struct seq_file *m, struct file *f);
+#ifndef CONFIG_MMU
+       unsigned (*mmap_capabilities)(struct file *);
+#endif
 };
 
 Again, all methods are called without any locks being held, unless