diff options
Diffstat (limited to 'kernel/Documentation/filesystems/vfs.txt')
| -rw-r--r-- | kernel/Documentation/filesystems/vfs.txt | 41 |
1 files changed, 24 insertions, 17 deletions
diff --git a/kernel/Documentation/filesystems/vfs.txt b/kernel/Documentation/filesystems/vfs.txt index 5d833b32b..8c6f07ad3 100644 --- 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 |