fs/9p: Rework cache modes and add new options to Documentation

Switch cache modes to a bit-mask and use legacy
cache names as shortcuts.  Update documentation to
include information on both shortcuts and bitmasks.

This patch also fixes missing guards related to fscache.

Update the documentation for new mount flags
and cache modes.

Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>

1 files changed, 23 insertions, 11 deletions

diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index fb5e5c0e41e4..54dfe4f10f43 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -371,17 +371,23 @@ struct inode *v9fs_get_inode(struct super_block *sb, umode_t mode, dev_t rdev)
  */
 void v9fs_evict_inode(struct inode *inode)
 {
-	struct v9fs_inode *v9inode = V9FS_I(inode);
-	__le32 version;
+	struct v9fs_inode __maybe_unused *v9inode = V9FS_I(inode);
+	__le32 __maybe_unused version;
 
 	truncate_inode_pages_final(&inode->i_data);
+
+#ifdef CONFIG_9P_FSCACHE
 	version = cpu_to_le32(v9inode->qid.version);
 	fscache_clear_inode_writeback(v9fs_inode_cookie(v9inode), inode,
 				      &version);
+#endif
+
 	clear_inode(inode);
 	filemap_fdatawrite(&inode->i_data);
 
+#ifdef CONFIG_9P_FSCACHE
 	fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false);
+#endif
 }
 
 static int v9fs_test_inode(struct inode *inode, void *data)
@@ -761,7 +767,7 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 		inode = NULL;
 	else if (IS_ERR(fid))
 		inode = ERR_CAST(fid);
-	else if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
+	else if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
 		inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
 	else
 		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
@@ -790,7 +796,7 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 {
 	int err;
 	u32 perm;
-	struct v9fs_inode *v9inode;
+	struct v9fs_inode __maybe_unused *v9inode;
 	struct v9fs_session_info *v9ses;
 	struct p9_fid *fid;
 	struct dentry *res = NULL;
@@ -816,7 +822,7 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 	perm = unixmode2p9mode(v9ses, mode);
 	p9_omode = v9fs_uflags2omode(flags, v9fs_proto_dotu(v9ses));
 
-	if ((v9ses->cache >= CACHE_WRITEBACK) && (p9_omode & P9_OWRITE)) {
+	if ((v9ses->cache & CACHE_WRITEBACK) && (p9_omode & P9_OWRITE)) {
 		p9_omode = (p9_omode & !P9_OWRITE) | P9_ORDWR;
 		p9_debug(P9_DEBUG_CACHE,
 			"write-only file with writeback enabled, creating w/ O_RDWR\n");
@@ -835,9 +841,11 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 		goto error;
 
 	file->private_data = fid;
-	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
+#ifdef CONFIG_9P_FSCACHE
+	if (v9ses->cache & CACHE_FSCACHE)
 		fscache_use_cookie(v9fs_inode_cookie(v9inode),
 				   file->f_mode & FMODE_WRITE);
+#endif
 
 	v9fs_fid_add_modes(fid, v9ses->flags, v9ses->cache, file->f_flags);
 	v9fs_open_fid_add(inode, &fid);
@@ -1008,10 +1016,10 @@ v9fs_vfs_getattr(struct mnt_idmap *idmap, const struct path *path,
 
 	p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
 	v9ses = v9fs_dentry2v9ses(dentry);
-	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
+	if (v9ses->cache & (CACHE_META|CACHE_LOOSE)) {
 		generic_fillattr(&nop_mnt_idmap, inode, stat);
 		return 0;
-	} else if (v9ses->cache >= CACHE_WRITEBACK) {
+	} else if (v9ses->cache & CACHE_WRITEBACK) {
 		if (S_ISREG(inode->i_mode)) {
 			int retval = filemap_fdatawrite(inode->i_mapping);
 
@@ -1050,7 +1058,6 @@ static int v9fs_vfs_setattr(struct mnt_idmap *idmap,
 {
 	int retval, use_dentry = 0;
 	struct inode *inode = d_inode(dentry);
-	struct v9fs_inode *v9inode = V9FS_I(inode);
 	struct v9fs_session_info *v9ses;
 	struct p9_fid *fid = NULL;
 	struct p9_wstat wstat;
@@ -1115,8 +1122,13 @@ static int v9fs_vfs_setattr(struct mnt_idmap *idmap,
 		truncate_setsize(inode, iattr->ia_size);
 		truncate_pagecache(inode, iattr->ia_size);
 
-		if (v9ses->cache == CACHE_FSCACHE)
+#ifdef CONFIG_9P_FSCACHE
+		if (v9ses->cache & CACHE_FSCACHE) {
+			struct v9fs_inode *v9inode = V9FS_I(inode);
+
 			fscache_resize_cookie(v9fs_inode_cookie(v9inode), iattr->ia_size);
+		}
+#endif
 	}
 
 	v9fs_invalidate_inode_attr(inode);
@@ -1400,7 +1412,7 @@ int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
 	 * We don't want to refresh inode->i_size,
 	 * because we may have cached data
 	 */
-	flags = (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) ?
+	flags = (v9ses->cache & CACHE_LOOSE) ?
 		V9FS_STAT2INODE_KEEP_ISIZE : 0;
 	v9fs_stat2inode(st, inode, inode->i_sb, flags);
 out: