Merge git://oss.sgi.com:8090/xfs/xfs-2.6

[sfrench/cifs-2.6.git] / Documentation / filesystems / Locking

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index eb1a6cad21e6a8cadc993111b1f4c7099d794ad2..59c14159cc47ddce04a19ae48d559fabedcf6902 100644 (file)
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -15,6 +15,7 @@ prototypes:
        int (*d_delete)(struct dentry *);
        void (*d_release)(struct dentry *);
        void (*d_iput)(struct dentry *, struct inode *);
+       char *(*d_dname)((struct dentry *dentry, char *buffer, int buflen);
 
 locking rules:
        none have BKL
@@ -25,6 +26,7 @@ d_compare:    no              yes             no              no
 d_delete:      yes             no              yes             no
 d_release:     no              no              no              yes
 d_iput:                no              no              no              yes
+d_dname:       no              no              no              no
 
 --------------------------- inode_operations --------------------------- 
 prototypes:
@@ -124,7 +126,7 @@ sync_fs:            no      no      read
 write_super_lockfs:    ?
 unlockfs:              ?
 statfs:                        no      no      no
-remount_fs:            no      yes     maybe           (see below)
+remount_fs:            yes     yes     maybe           (see below)
 clear_inode:           no
 umount_begin:          yes     no      no
 show_options:          no                              (vfsmount->sem)
@@ -171,6 +173,7 @@ prototypes:
        int (*releasepage) (struct page *, int);
        int (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
                        loff_t offset, unsigned long nr_segs);
+       int (*launder_page) (struct page *);
 
 locking rules:
        All except set_page_dirty may block
@@ -188,6 +191,7 @@ bmap:                       yes
 invalidatepage:                no      yes
 releasepage:           no      yes
 direct_IO:             no
+launder_page:          no      yes
 
        ->prepare_write(), ->commit_write(), ->sync_page() and ->readpage()
 may be called from the request handler (/dev/loop).
@@ -281,6 +285,12 @@ buffers from the page in preparation for freeing it.  It returns zero to
 indicate that the buffers are (or may be) freeable.  If ->releasepage is zero,
 the kernel assumes that the fs has no private interest in the buffers.
 
+       ->launder_page() may be called prior to releasing a page if
+it is still found to be dirty. It returns zero if the page was successfully
+cleaned, or an error value if not. Note that in order to prevent the page
+getting mapped back in and redirtied, it needs to be kept locked
+across the entire operation.
+
        Note: currently almost all instances of address_space methods are
 using BKL for internal serialization and that's one of the worst sources
 of contention. Normally they are calling library functions (in fs/buffer.c)