vserver 1.9.5.x5

[linux-2.6.git] / Documentation / filesystems / Locking

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 1c465ed..2c9ce27 100644 (file)
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -90,7 +90,7 @@ prototypes:
        void (*destroy_inode)(struct inode *);
        void (*read_inode) (struct inode *);
        void (*dirty_inode) (struct inode *);
-       void (*write_inode) (struct inode *, int);
+       int (*write_inode) (struct inode *, int);
        void (*put_inode) (struct inode *);
        void (*drop_inode) (struct inode *);
        void (*delete_inode) (struct inode *);
@@ -276,21 +276,40 @@ foo_get_block(). It's an overkill, since block bitmaps can be protected by
 internal fs locking and real critical areas are much smaller than the areas
 filesystems protect now.
 
---------------------------- file_lock ------------------------------------
+----------------------- file_lock_operations ------------------------------
 prototypes:
-       void (*fl_notify)(struct file_lock *);  /* unblock callback */
        void (*fl_insert)(struct file_lock *);  /* lock insertion callback */
        void (*fl_remove)(struct file_lock *);  /* lock removal callback */
+       void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
+       void (*fl_release_private)(struct file_lock *);
+
 
 locking rules:
-               BKL     may block
-fl_notify:     yes     no
-fl_insert:     yes     no
-fl_remove:     yes     no
-       Currently only NLM provides instances of this class. None of the
+                       BKL     may block
+fl_insert:             yes     no
+fl_remove:             yes     no
+fl_copy_lock:          yes     no
+fl_release_private:    yes     yes
+
+----------------------- lock_manager_operations ---------------------------
+prototypes:
+       int (*fl_compare_owner)(struct file_lock *, struct file_lock *);
+       void (*fl_notify)(struct file_lock *);  /* unblock callback */
+       void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
+       void (*fl_release_private)(struct file_lock *);
+       void (*fl_break)(struct file_lock *); /* break_lease callback */
+
+locking rules:
+                       BKL     may block
+fl_compare_owner:      yes     no
+fl_notify:             yes     no
+fl_copy_lock:          yes     no
+fl_release_private:    yes     yes
+fl_break:              yes     no
+
+       Currently only NFSD and NLM provide instances of this class. None of the
 them block. If you have out-of-tree instances - please, show up. Locking
 in that area will change.
-
 --------------------------- buffer_head -----------------------------------
 prototypes:
        void (*b_end_io)(struct buffer_head *bh, int uptodate);
@@ -298,8 +317,8 @@ prototypes:
 locking rules:
        called from interrupts. In other words, extreme care is needed here.
 bh is locked, but that's all warranties we have here. Currently only RAID1,
-highmem and fs/buffer.c are providing these. Block devices call this method
-upon the IO completion.
+highmem, fs/buffer.c, and fs/ntfs/aops.c are providing these. Block devices
+call this method upon the IO completion.
 
 --------------------------- block_device_operations -----------------------
 prototypes:
@@ -331,6 +350,8 @@ prototypes:
        unsigned int (*poll) (struct file *, struct poll_table_struct *);
        int (*ioctl) (struct inode *, struct file *, unsigned int,
                        unsigned long);
+       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 (*open) (struct inode *, struct file *);
        int (*flush) (struct file *);
@@ -364,6 +385,8 @@ aio_write:          no
 readdir:               no
 poll:                  no
 ioctl:                 yes     (see below)
+unlocked_ioctl:                no      (see below)
+compat_ioctl:          no
 mmap:                  no
 open:                  maybe   (see below)
 flush:                 no
@@ -409,6 +432,9 @@ move ->readdir() to inode_operations and use a separate method for directory
 anything that resembles union-mount we won't have a struct file for all
 components. And there are other reasons why the current interface is a mess...
 
+->ioctl() on regular files is superceded by the ->unlocked_ioctl() that
+doesn't take the BKL.
+
 ->read on directories probably must go away - we should just enforce -EISDIR
 in sys_read() and friends.