[PATCH v2 31/53] cachefiles: Define structs

[David Howells <dhowells@redhat.com>]

Define structures to represent the state inside cachefiles.  There are
three structures:

 (1) struct cachefiles_cache.

     This represents the cache as a whole and is used to keep track of the
     cache parameters and security, the communication channel to the
     controlling daemon and various directories in the cache filesystem.

 (2) struct cachefiles_volume.

     This represents a volume in the cache.  It keeps track of the
     directory for the volume and the fanout subdirs that form a hash
     table.

 (3) struct cachefiles_object.

     This represents a data file in the cache.  It keeps track of the
     filename and the open file handle for the relevant file.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
---

 fs/cachefiles/internal.h |   86 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index 2f8e2835a785..11dcf9dbcf05 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -19,11 +19,97 @@
 #include <linux/workqueue.h>
 #include <linux/security.h>
 
+struct cachefiles_cache;
+struct cachefiles_object;
+
 extern unsigned cachefiles_debug;
 #define CACHEFILES_DEBUG_KENTER	1
 #define CACHEFILES_DEBUG_KLEAVE	2
 #define CACHEFILES_DEBUG_KDEBUG	4
 
+enum cachefiles_content {
+	/* These values are saved on disk */
+	CACHEFILES_CONTENT_NO_DATA	= 0, /* No content stored */
+	CACHEFILES_CONTENT_SINGLE	= 1, /* Content is monolithic, all is present */
+	CACHEFILES_CONTENT_ALL		= 2, /* Content is all present, no map */
+	CACHEFILES_CONTENT_BACKFS_MAP	= 3, /* Content is piecemeal, mapped through backing fs */
+	CACHEFILES_CONTENT_DIRTY	= 4, /* Content is dirty (only seen on disk) */
+	nr__cachefiles_content
+};
+
+/*
+ * Cached volume representation.
+ */
+struct cachefiles_volume {
+	struct cachefiles_cache		*cache;
+	struct list_head		cache_link;	/* Link in cache->volumes */
+	struct fscache_volume		*vcookie;	/* The netfs's representation */
+	struct dentry			*dentry;	/* The volume dentry */
+	struct dentry			*fanout[256];	/* Fanout subdirs */
+};
+
+/*
+ * node records
+ */
+struct cachefiles_object {
+	int				debug_id;	/* debugging ID */
+	spinlock_t			lock;		/* state and operations lock */
+
+	struct list_head		cache_link;	/* Link in cache->*_list */
+	struct cachefiles_volume	*volume;	/* Cache volume that holds this object */
+	struct fscache_cookie		*cookie;	/* netfs's file/index object */
+	struct file			*file;		/* The file representing this object */
+	char				*d_name;	/* Filename */
+	atomic_t			usage;		/* object usage count */
+	u8				d_name_len;	/* Length of filename */
+	u8				key_hash;	/* Hash of object key */
+	unsigned long			flags;
+#define CACHEFILES_OBJECT_USING_TMPFILE	0		/* Have an unlinked tmpfile */
+	enum cachefiles_content		content_info:8;	/* Info about content presence */
+};
+
+/*
+ * Cache files cache definition
+ */
+struct cachefiles_cache {
+	struct fscache_cache		*cache;		/* Cache cookie */
+	struct vfsmount			*mnt;		/* mountpoint holding the cache */
+	struct dentry			*store;		/* Directory into which live objects go */
+	struct dentry			*graveyard;	/* directory into which dead objects go */
+	struct file			*cachefilesd;	/* manager daemon handle */
+	struct list_head		volumes;	/* List of volume objects */
+	struct list_head		object_list;	/* List of active objects */
+	spinlock_t			object_list_lock;
+	const struct cred		*cache_cred;	/* security override for accessing cache */
+	struct mutex			daemon_mutex;	/* command serialisation mutex */
+	wait_queue_head_t		daemon_pollwq;	/* poll waitqueue for daemon */
+	atomic_t			gravecounter;	/* graveyard uniquifier */
+	atomic_t			f_released;	/* number of objects released lately */
+	atomic_long_t			b_released;	/* number of blocks released lately */
+	unsigned			frun_percent;	/* when to stop culling (% files) */
+	unsigned			fcull_percent;	/* when to start culling (% files) */
+	unsigned			fstop_percent;	/* when to stop allocating (% files) */
+	unsigned			brun_percent;	/* when to stop culling (% blocks) */
+	unsigned			bcull_percent;	/* when to start culling (% blocks) */
+	unsigned			bstop_percent;	/* when to stop allocating (% blocks) */
+	unsigned			bsize;		/* cache's block size */
+	unsigned			bshift;		/* min(ilog2(PAGE_SIZE / bsize), 0) */
+	uint64_t			frun;		/* when to stop culling */
+	uint64_t			fcull;		/* when to start culling */
+	uint64_t			fstop;		/* when to stop allocating */
+	sector_t			brun;		/* when to stop culling */
+	sector_t			bcull;		/* when to start culling */
+	sector_t			bstop;		/* when to stop allocating */
+	unsigned long			flags;
+#define CACHEFILES_READY		0	/* T if cache prepared */
+#define CACHEFILES_DEAD			1	/* T if cache dead */
+#define CACHEFILES_CULLING		2	/* T if cull engaged */
+#define CACHEFILES_STATE_CHANGED	3	/* T if state changed (poll trigger) */
+	char				*rootdirname;	/* name of cache root directory */
+	char				*secctx;	/* LSM security context */
+	char				*tag;		/* cache binding tag */
+};
+
 /*
  * error_inject.c
  */