path: root/Documentation/filesystems/vfs.txt
diff options
Diffstat (limited to 'Documentation/filesystems/vfs.txt')
1 files changed, 29 insertions, 10 deletions
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index efd23f48170..2ee133e030c 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -216,7 +216,6 @@ struct super_operations {
void (*drop_inode) (struct inode *);
void (*delete_inode) (struct inode *);
void (*put_super) (struct super_block *);
- void (*write_super) (struct super_block *);
int (*sync_fs)(struct super_block *sb, int wait);
int (*freeze_fs) (struct super_block *);
int (*unfreeze_fs) (struct super_block *);
@@ -273,9 +272,6 @@ or bottom half).
put_super: called when the VFS wishes to free the superblock
(i.e. unmount). This is called with the superblock lock held
- write_super: called when the VFS superblock needs to be written to
- disc. This method is optional
sync_fs: called when VFS is writing out all dirty data associated with
a superblock. The second parameter indicates whether the method
should wait until the write out has been completed. Optional.
@@ -341,8 +337,8 @@ This describes how the VFS can manipulate an inode in your
filesystem. As of kernel 2.6.22, the following members are defined:
struct inode_operations {
- int (*create) (struct inode *,struct dentry *, umode_t, struct nameidata *);
- struct dentry * (*lookup) (struct inode *,struct dentry *, struct nameidata *);
+ int (*create) (struct inode *,struct dentry *, umode_t, bool);
+ struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
int (*link) (struct dentry *,struct inode *,struct dentry *);
int (*unlink) (struct inode *,struct dentry *);
int (*symlink) (struct inode *,struct dentry *,const char *);
@@ -364,6 +360,9 @@ struct inode_operations {
ssize_t (*listxattr) (struct dentry *, char *, size_t);
int (*removexattr) (struct dentry *, const char *);
void (*update_time)(struct inode *, struct timespec *, int);
+ int (*atomic_open)(struct inode *, struct dentry *,
+ struct file *, unsigned open_flag,
+ umode_t create_mode, int *opened);
Again, all methods are called without any locks being held, unless
@@ -476,6 +475,14 @@ otherwise noted.
an inode. If this is not defined the VFS will update the inode itself
and call mark_inode_dirty_sync.
+ atomic_open: called on the last component of an open. Using this optional
+ method the filesystem can look up, possibly create and open the file in
+ one atomic operation. If it cannot perform this (e.g. the file type
+ turned out to be wrong) it may signal this by returning 1 instead of
+ usual 0 or -ve . This method is only called if the last
+ component is negative or needs lookup. Cached positive dentries are
+ still handled by f_op->open().
The Address Space Object
@@ -581,6 +588,8 @@ struct address_space_operations {
int (*migratepage) (struct page *, struct page *);
int (*launder_page) (struct page *);
int (*error_remove_page) (struct mapping *mapping, struct page *page);
+ int (*swap_activate)(struct file *);
+ int (*swap_deactivate)(struct file *);
writepage: called by the VM to write a dirty page to backing store.
@@ -749,6 +758,16 @@ struct address_space_operations {
Setting this implies you deal with pages going away under you,
unless you have them locked or reference counts increased.
+ swap_activate: Called when swapon is used on a file to allocate
+ space if necessary and pin the block lookup information in
+ memory. A return value of zero indicates success,
+ in which case this file can be used to back swapspace. The
+ swapspace operations will be proxied to this address space's
+ ->swap_{out,in} methods.
+ swap_deactivate: Called during swapoff on files where swap_activate
+ was successful.
The File Object
@@ -891,7 +910,7 @@ the VFS uses a default. As of kernel 2.6.22, the following members are
struct dentry_operations {
- int (*d_revalidate)(struct dentry *, struct nameidata *);
+ int (*d_revalidate)(struct dentry *, unsigned int);
int (*d_hash)(const struct dentry *, const struct inode *,
struct qstr *);
int (*d_compare)(const struct dentry *, const struct inode *,
@@ -910,11 +929,11 @@ struct dentry_operations {
dcache. Most filesystems leave this as NULL, because all their
dentries in the dcache are valid
- d_revalidate may be called in rcu-walk mode (nd->flags & LOOKUP_RCU).
+ d_revalidate may be called in rcu-walk mode (flags & LOOKUP_RCU).
If in rcu-walk mode, the filesystem must revalidate the dentry without
blocking or storing to the dentry, d_parent and d_inode should not be
- used without care (because they can go NULL), instead nd->inode should
- be used.
+ used without care (because they can change and, in d_inode case, even
+ become NULL under us).
If a situation is encountered that rcu-walk cannot handle, return
-ECHILD and it will be called again in ref-walk mode.