diff options
Diffstat (limited to 'Documentation/filesystems/vfs.txt')
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index efd23f481704..aa754e01464e 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -341,8 +341,8 @@ 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 +364,9 @@ 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 +479,14 @@ 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 ======================== @@ -891,7 +902,7 @@ the VFS uses a default. As of kernel 2.6.22, the following members are defined: 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 +921,11 @@ 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. |