Merge tag 'fscache-fixes-20220121' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull more fscache updates from David Howells:
 "A set of fixes and minor updates for the fscache rewrite:

   - Fix mishandling of volume collisions (the wait condition is
     inverted and so it was only waiting if the volume collision was
     already resolved).

   - Fix miscalculation of whether there's space available in
     cachefiles.

   - Make sure a default cache name is set on a cache if the user hasn't
     set one by the time they bind the cache.

   - Adjust the way the backing inode is presented in tracepoints, add a
     tracepoint for mkdir and trace directory lookup.

   - Add a tracepoint for failure to set the active file mark.

   - Add an explanation of the checks made on the backing filesystem.

   - Check that the backing filesystem supports tmpfile.

   - Document how the page-release cancellation of the read-skip
     optimisation works.

  And I've included a change for netfslib:

   - Make ops->init_rreq() optional"

* tag 'fscache-fixes-20220121' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  netfs: Make ops->init_rreq() optional
  fscache: Add a comment explaining how page-release optimisation works
  cachefiles: Check that the backing filesystem supports tmpfiles
  cachefiles: Explain checks in a comment
  cachefiles: Trace active-mark failure
  cachefiles: Make some tracepoint adjustments
  cachefiles: set default tag name if it's unspecified
  cachefiles: Calculate the blockshift in terms of bytes, not pages
  fscache: Fix the volume collision wait condition

2 files changed, 77 insertions, 31 deletions

diff --git a/include/linux/fscache.h b/include/linux/fscache.h
index ede50406bcb0..296c5f1d9f35 100644
--- a/include/linux/fscache.h
+++ b/include/linux/fscache.h
@@ -665,6 +665,11 @@ static inline void fscache_clear_inode_writeback(struct fscache_cookie *cookie,
 static inline
 void fscache_note_page_release(struct fscache_cookie *cookie)
 {
+	/* If we've written data to the cache (HAVE_DATA) and there wasn't any
+	 * data in the cache when we started (NO_DATA_TO_READ), it may no
+	 * longer be true that we can skip reading from the cache - so clear
+	 * the flag that causes reads to be skipped.
+	 */
 	if (cookie &&
 	    test_bit(FSCACHE_COOKIE_HAVE_DATA, &cookie->flags) &&
 	    test_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags))
diff --git a/include/trace/events/cachefiles.h b/include/trace/events/cachefiles.h
index 1172529b5b49..c6f5aa74db89 100644
--- a/include/trace/events/cachefiles.h
+++ b/include/trace/events/cachefiles.h
@@ -233,25 +233,48 @@ TRACE_EVENT(cachefiles_ref,
 
 TRACE_EVENT(cachefiles_lookup,
 	    TP_PROTO(struct cachefiles_object *obj,
+		     struct dentry *dir,
 		     struct dentry *de),
 
-	    TP_ARGS(obj, de),
+	    TP_ARGS(obj, dir, de),
 
 	    TP_STRUCT__entry(
 		    __field(unsigned int,		obj	)
 		    __field(short,			error	)
+		    __field(unsigned long,		dino	)
 		    __field(unsigned long,		ino	)
 			     ),
 
 	    TP_fast_assign(
-		    __entry->obj	= obj->debug_id;
+		    __entry->obj	= obj ? obj->debug_id : 0;
+		    __entry->dino	= d_backing_inode(dir)->i_ino;
 		    __entry->ino	= (!IS_ERR(de) && d_backing_inode(de) ?
 					   d_backing_inode(de)->i_ino : 0);
 		    __entry->error	= IS_ERR(de) ? PTR_ERR(de) : 0;
 			   ),
 
-	    TP_printk("o=%08x i=%lx e=%d",
-		      __entry->obj, __entry->ino, __entry->error)
+	    TP_printk("o=%08x dB=%lx B=%lx e=%d",
+		      __entry->obj, __entry->dino, __entry->ino, __entry->error)
+	    );
+
+TRACE_EVENT(cachefiles_mkdir,
+	    TP_PROTO(struct dentry *dir, struct dentry *subdir),
+
+	    TP_ARGS(dir, subdir),
+
+	    TP_STRUCT__entry(
+		    __field(unsigned int,			dir	)
+		    __field(unsigned int,			subdir	)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->dir	= d_backing_inode(dir)->i_ino;
+		    __entry->subdir	= d_backing_inode(subdir)->i_ino;
+			   ),
+
+	    TP_printk("dB=%x sB=%x",
+		      __entry->dir,
+		      __entry->subdir)
 	    );
 
 TRACE_EVENT(cachefiles_tmpfile,
@@ -269,7 +292,7 @@ TRACE_EVENT(cachefiles_tmpfile,
 		    __entry->backer	= backer->i_ino;
 			   ),
 
-	    TP_printk("o=%08x b=%08x",
+	    TP_printk("o=%08x B=%x",
 		      __entry->obj,
 		      __entry->backer)
 	    );
@@ -289,61 +312,58 @@ TRACE_EVENT(cachefiles_link,
 		    __entry->backer	= backer->i_ino;
 			   ),
 
-	    TP_printk("o=%08x b=%08x",
+	    TP_printk("o=%08x B=%x",
 		      __entry->obj,
 		      __entry->backer)
 	    );
 
 TRACE_EVENT(cachefiles_unlink,
 	    TP_PROTO(struct cachefiles_object *obj,
-		     struct dentry *de,
+		     ino_t ino,
 		     enum fscache_why_object_killed why),
 
-	    TP_ARGS(obj, de, why),
+	    TP_ARGS(obj, ino, why),
 
 	    /* Note that obj may be NULL */
 	    TP_STRUCT__entry(
 		    __field(unsigned int,		obj		)
-		    __field(struct dentry *,		de		)
+		    __field(unsigned int,		ino		)
 		    __field(enum fscache_why_object_killed, why		)
 			     ),
 
 	    TP_fast_assign(
 		    __entry->obj	= obj ? obj->debug_id : UINT_MAX;
-		    __entry->de		= de;
+		    __entry->ino	= ino;
 		    __entry->why	= why;
 			   ),
 
-	    TP_printk("o=%08x d=%p w=%s",
-		      __entry->obj, __entry->de,
+	    TP_printk("o=%08x B=%x w=%s",
+		      __entry->obj, __entry->ino,
 		      __print_symbolic(__entry->why, cachefiles_obj_kill_traces))
 	    );
 
 TRACE_EVENT(cachefiles_rename,
 	    TP_PROTO(struct cachefiles_object *obj,
-		     struct dentry *de,
-		     struct dentry *to,
+		     ino_t ino,
 		     enum fscache_why_object_killed why),
 
-	    TP_ARGS(obj, de, to, why),
+	    TP_ARGS(obj, ino, why),
 
 	    /* Note that obj may be NULL */
 	    TP_STRUCT__entry(
 		    __field(unsigned int,		obj		)
-		    __field(struct dentry *,		de		)
-		    __field(struct dentry *,		to		)
+		    __field(unsigned int,		ino		)
 		    __field(enum fscache_why_object_killed, why		)
 			     ),
 
 	    TP_fast_assign(
 		    __entry->obj	= obj ? obj->debug_id : UINT_MAX;
-		    __entry->de		= de;
-		    __entry->to		= to;
+		    __entry->ino	= ino;
 		    __entry->why	= why;
 			   ),
 
-	    TP_printk("o=%08x d=%p t=%p w=%s",
-		      __entry->obj, __entry->de, __entry->to,
+	    TP_printk("o=%08x B=%x w=%s",
+		      __entry->obj, __entry->ino,
 		      __print_symbolic(__entry->why, cachefiles_obj_kill_traces))
 	    );
 
@@ -370,7 +390,7 @@ TRACE_EVENT(cachefiles_coherency,
 		    __entry->ino	= ino;
 			   ),
 
-	    TP_printk("o=%08x %s i=%llx c=%u",
+	    TP_printk("o=%08x %s B=%llx c=%u",
 		      __entry->obj,
 		      __print_symbolic(__entry->why, cachefiles_coherency_traces),
 		      __entry->ino,
@@ -397,7 +417,7 @@ TRACE_EVENT(cachefiles_vol_coherency,
 		    __entry->ino	= ino;
 			   ),
 
-	    TP_printk("V=%08x %s i=%llx",
+	    TP_printk("V=%08x %s B=%llx",
 		      __entry->vol,
 		      __print_symbolic(__entry->why, cachefiles_coherency_traces),
 		      __entry->ino)
@@ -435,7 +455,7 @@ TRACE_EVENT(cachefiles_prep_read,
 		    __entry->cache_inode = cache_inode;
 			   ),
 
-	    TP_printk("R=%08x[%u] %s %s f=%02x s=%llx %zx ni=%x b=%x",
+	    TP_printk("R=%08x[%u] %s %s f=%02x s=%llx %zx ni=%x B=%x",
 		      __entry->rreq, __entry->index,
 		      __print_symbolic(__entry->source, netfs_sreq_sources),
 		      __print_symbolic(__entry->why, cachefiles_prepare_read_traces),
@@ -466,7 +486,7 @@ TRACE_EVENT(cachefiles_read,
 		    __entry->len	= len;
 			   ),
 
-	    TP_printk("o=%08x b=%08x s=%llx l=%zx",
+	    TP_printk("o=%08x B=%x s=%llx l=%zx",
 		      __entry->obj,
 		      __entry->backer,
 		      __entry->start,
@@ -495,7 +515,7 @@ TRACE_EVENT(cachefiles_write,
 		    __entry->len	= len;
 			   ),
 
-	    TP_printk("o=%08x b=%08x s=%llx l=%zx",
+	    TP_printk("o=%08x B=%x s=%llx l=%zx",
 		      __entry->obj,
 		      __entry->backer,
 		      __entry->start,
@@ -524,7 +544,7 @@ TRACE_EVENT(cachefiles_trunc,
 		    __entry->why	= why;
 			   ),
 
-	    TP_printk("o=%08x b=%08x %s l=%llx->%llx",
+	    TP_printk("o=%08x B=%x %s l=%llx->%llx",
 		      __entry->obj,
 		      __entry->backer,
 		      __print_symbolic(__entry->why, cachefiles_trunc_traces),
@@ -549,7 +569,28 @@ TRACE_EVENT(cachefiles_mark_active,
 		    __entry->inode	= inode->i_ino;
 			   ),
 
-	    TP_printk("o=%08x i=%lx",
+	    TP_printk("o=%08x B=%lx",
+		      __entry->obj, __entry->inode)
+	    );
+
+TRACE_EVENT(cachefiles_mark_failed,
+	    TP_PROTO(struct cachefiles_object *obj,
+		     struct inode *inode),
+
+	    TP_ARGS(obj, inode),
+
+	    /* Note that obj may be NULL */
+	    TP_STRUCT__entry(
+		    __field(unsigned int,		obj		)
+		    __field(ino_t,			inode		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->obj	= obj ? obj->debug_id : 0;
+		    __entry->inode	= inode->i_ino;
+			   ),
+
+	    TP_printk("o=%08x B=%lx",
 		      __entry->obj, __entry->inode)
 	    );
 
@@ -570,7 +611,7 @@ TRACE_EVENT(cachefiles_mark_inactive,
 		    __entry->inode	= inode->i_ino;
 			   ),
 
-	    TP_printk("o=%08x i=%lx",
+	    TP_printk("o=%08x B=%lx",
 		      __entry->obj, __entry->inode)
 	    );
 
@@ -594,7 +635,7 @@ TRACE_EVENT(cachefiles_vfs_error,
 		    __entry->where	= where;
 			   ),
 
-	    TP_printk("o=%08x b=%08x %s e=%d",
+	    TP_printk("o=%08x B=%x %s e=%d",
 		      __entry->obj,
 		      __entry->backer,
 		      __print_symbolic(__entry->where, cachefiles_error_traces),
@@ -621,7 +662,7 @@ TRACE_EVENT(cachefiles_io_error,
 		    __entry->where	= where;
 			   ),
 
-	    TP_printk("o=%08x b=%08x %s e=%d",
+	    TP_printk("o=%08x B=%x %s e=%d",
 		      __entry->obj,
 		      __entry->backer,
 		      __print_symbolic(__entry->where, cachefiles_error_traces),