DAOS-15338 dfuse: Configure fuse to allow writes to populate cache.

src/client/dfuse/dfuse.h

@@ -411,6 +411,7 @@ struct dfuse_event {
 	union {
 		size_t de_req_len;
 		size_t de_readahead_len;
+		struct dfuse_info *de_di;
 	};
 	void (*de_complete_cb)(struct dfuse_event *ev);
 	struct stat de_attr;
@@ -457,6 +458,7 @@ struct dfuse_pool {
 	ACTION(CREATE)                                                                             \
 	ACTION(MKNOD)                                                                              \
 	ACTION(FGETATTR)                                                                           \
+	ACTION(PRE_GETATTR)                                                                        \
 	ACTION(GETATTR)                                                                            \
 	ACTION(FSETATTR)                                                                           \
 	ACTION(SETATTR)                                                                            \
@@ -535,6 +537,9 @@ struct dfuse_cont {
 	double                  dfc_dentry_dir_timeout;
 	double                  dfc_ndentry_timeout;
 	double                  dfc_data_timeout;
+
+	double                        dfc_dentry_inval_time;
+
 	bool                    dfc_data_otoc;
 	bool                    dfc_direct_io_disable;
 	bool                          dfc_wb_cache;
@@ -551,9 +556,6 @@ struct dfuse_cont {
 #define DFUSE_IE_STAT_ADD(_ie, _stat)                                                              \
 	atomic_fetch_add_relaxed(&(_ie)->ie_dfs->dfs_stat_value[(_stat)], 1)
 
-void
-dfuse_set_default_cont_cache_values(struct dfuse_cont *dfc);
-
 /* Connect to a container via a label
  * Called either for labels on the command line or via dfuse_cont_get_handle() if opening via uuid
  *
@@ -749,7 +751,7 @@ dfuse_loop(struct dfuse_info *dfuse_info);
 		_Static_assert(IS_OH(_oh), "Param is not open handle");                            \
 		(_oh)->doh_ie = NULL;                                                              \
 		__rc          = fuse_reply_err(req, 0);                                            \
-		if (__rc != 0)                                                                     \
+		if ((__rc != 0) && (__rc != -ENOENT))                                              \
 			DS_ERROR(-__rc, "fuse_reply_err() error");                                 \
 	} while (0)
 
@@ -999,6 +1001,36 @@ struct dfuse_inode_entry {
 	/** File has been unlinked from daos */
 	bool                      ie_unlinked;
 
+	/* Data cache metadata, list known size/mtime for file, if these have been updated then
+	 * the data cache should be dropped.
+	 *
+	 * When the last fd on a file is closed and all writes are completed then dfuse will launch
+	 * a stat to get the update size/mtime for the inode.  Future opens should block on this
+	 * stat in order to know if the file has been updated.
+	 *
+	 * Access is controlled via atomics and semaphore, when a decision to make the stat is taken
+	 * then active in increased, and the sem is posted.
+	 *
+	 * Future accesses of the inode should check active, if the value is 0 then there is nothing
+	 * to do.
+	 * If active is positive then it should increase active, wait on the semaphore, decrease
+	 * active and then post the semaphore if active != 0;
+	 *
+	 * After active is 0, (or the semaphore has been waited on) then the new stat structure is
+	 * valid.
+	 *
+	 * The release() code to initialize stat is atomic as it's only triggered by the last
+	 * release on a inode.  It could race with open() where the inode is known in advance
+	 * or create() where it is not.  Open will flush the stat before setting keep_cache.
+	 */
+	struct {
+		struct stat     stat;
+		bool            valid;
+		ATOMIC uint32_t active;
+		struct timespec last_update;
+		sem_t           sem;
+	} ie_dc;
+
 	/* Lock for writes, shared locks are held during write-back reads, exclusive lock is
 	 * acquired and released to flush outstanding writes for getattr, close and forget.
 	 */
@@ -1016,6 +1048,8 @@ struct dfuse_inode_entry {
 	struct read_chunk_core   *ie_chunk;
 };
 
+void
+dfuse_ie_cs_flush(struct dfuse_inode_entry *ie);
 /* Flush write-back cache writes to a inode.  It does this by waiting for and then releasing an
  * exclusive lock on the inode.  Writes take a shared lock so this will block until all pending
  * writes are complete.
@@ -1136,6 +1170,11 @@ dfuse_mcache_get_valid(struct dfuse_inode_entry *ie, double max_age, double *tim
 bool
 dfuse_dentry_get_valid(struct dfuse_inode_entry *ie, double max_age, double *timeout);
 
+void
+dfuse_dc_cache_set_time(struct dfuse_inode_entry *ie);
+bool
+dfuse_dc_cache_get_valid(struct dfuse_inode_entry *ie, double max_age, double *timeout);
+
 /* inval.c */
 
 int

src/client/dfuse/dfuse_core.c

@@ -752,7 +752,7 @@ dfuse_cont_get_cache(struct dfuse_info *dfuse_info, struct dfuse_cont *dfc)
  * dentries which represent directories and are therefore referenced much
  * more often during path-walk activities are set to five seconds.
  */
-void
+static void
 dfuse_set_default_cont_cache_values(struct dfuse_cont *dfc)
 {
 	dfc->dfc_attr_timeout       = 1;
@@ -876,13 +876,29 @@ dfuse_cont_open(struct dfuse_info *dfuse_info, struct dfuse_pool *dfp, const cha
 		uuid_copy(dfc->dfc_uuid, c_info.ci_uuid);
 
 		if (dfuse_info->di_caching) {
+			double timeout;
+
 			rc = dfuse_cont_get_cache(dfuse_info, dfc);
 			if (rc == ENODATA) {
 				DFUSE_TRA_INFO(dfc, "Using default caching values");
 				dfuse_set_default_cont_cache_values(dfc);
 			} else if (rc != 0) {
 				D_GOTO(err_umount, rc);
 			}
+
+			/* Set the timeout for invalidate.  This is the duration after which inodes
+			 * will be evicted from the kernel.  Data timeout is considered here as
+			 * well as attrs are used to decide if keeping the data in cache is
+			 * correct.  Data timeout can be set to True/-1 so cap this duration at
+			 * ten minutes or nothing would ever get evicted.
+			 */
+			timeout = max(dfc->dfc_attr_timeout, dfc->dfc_data_timeout);
+
+			timeout = min(timeout, 10 * 60);
+
+			timeout = max(timeout, dfc->dfc_dentry_timeout);
+
+			dfc->dfc_dentry_inval_time = timeout + 3;
 		}
 
 		rc = ival_add_cont_buckets(dfc);
@@ -1048,6 +1064,51 @@ dfuse_mcache_get_valid(struct dfuse_inode_entry *ie, double max_age, double *tim
 	return use;
 }
 
+/* Set a timer to mark cache entry as valid */
+void
+dfuse_dc_cache_set_time(struct dfuse_inode_entry *ie)
+{
+	struct timespec now;
+
+	clock_gettime(CLOCK_MONOTONIC_COARSE, &now);
+	ie->ie_dc.last_update = now;
+}
+
+bool
+dfuse_dc_cache_get_valid(struct dfuse_inode_entry *ie, double max_age, double *timeout)
+{
+	bool            use = false;
+	struct timespec now;
+	struct timespec left;
+	double          time_left;
+
+	D_ASSERT(max_age != -1);
+	D_ASSERT(max_age >= 0);
+
+	if (ie->ie_dc.last_update.tv_sec == 0)
+		return false;
+
+	clock_gettime(CLOCK_MONOTONIC_COARSE, &now);
+
+	left.tv_sec  = now.tv_sec - ie->ie_dc.last_update.tv_sec;
+	left.tv_nsec = now.tv_nsec - ie->ie_dc.last_update.tv_nsec;
+	if (left.tv_nsec < 0) {
+		left.tv_sec--;
+		left.tv_nsec += 1000000000;
+	}
+	time_left = max_age - (left.tv_sec + ((double)left.tv_nsec / 1000000000));
+	if (time_left > 0) {
+		use = true;
+
+		DFUSE_TRA_DEBUG(ie, "Allowing cache use, time remaining: %.1lf", time_left);
+
+		if (timeout)
+			*timeout = time_left;
+	}
+
+	return use;
+}
+
 bool
 dfuse_dentry_get_valid(struct dfuse_inode_entry *ie, double max_age, double *timeout)
 {
@@ -1251,6 +1312,7 @@ dfuse_ie_init(struct dfuse_info *dfuse_info, struct dfuse_inode_entry *ie)
 	atomic_init(&ie->ie_open_count, 0);
 	atomic_init(&ie->ie_open_write_count, 0);
 	atomic_init(&ie->ie_il_count, 0);
+	sem_init(&ie->ie_dc.sem, 0, 0);
 	atomic_init(&ie->ie_linear_read, true);
 	atomic_fetch_add_relaxed(&dfuse_info->di_inode_count, 1);
 	D_INIT_LIST_HEAD(&ie->ie_evict_entry);

src/client/dfuse/dfuse_fuseops.c

@@ -1,5 +1,5 @@
 /**
- * (C) Copyright 2016-2023 Intel Corporation.
+ * (C) Copyright 2016-2024 Intel Corporation.
  *
  * SPDX-License-Identifier: BSD-2-Clause-Patent
  */
@@ -54,6 +54,12 @@ dfuse_show_flags(void *handle, unsigned int cap, unsigned int want)
 #ifdef FUSE_CAP_EXPLICIT_INVAL_DATA
 	SHOW_FLAG(handle, cap, want, FUSE_CAP_EXPLICIT_INVAL_DATA);
 #endif
+#ifdef FUSE_CAP_EXPIRE_ONLY
+	SHOW_FLAG(handle, cap, want, FUSE_CAP_EXPIRE_ONLY);
+#endif
+#ifdef FUSE_CAP_SETXATTR_EXT
+	SHOW_FLAG(handle, cap, want, FUSE_CAP_SETXATTR_EXT);
+#endif
 
 	if (cap)
 		DFUSE_TRA_WARNING(handle, "Unknown capability flags %#x", cap);
@@ -90,6 +96,12 @@ dfuse_fuse_init(void *arg, struct fuse_conn_info *conn)
 	conn->want |= FUSE_CAP_READDIRPLUS;
 	conn->want |= FUSE_CAP_READDIRPLUS_AUTO;
 
+#ifdef FUSE_CAP_EXPLICIT_INVAL_DATA
+	/* DAOS-15338 Do not let the kernel evict data on mtime changes */
+	conn->want |= FUSE_CAP_EXPLICIT_INVAL_DATA;
+	conn->want &= ~FUSE_CAP_AUTO_INVAL_DATA;
+#endif
+
 #ifdef FUSE_CAP_CACHE_SYMLINKS
 	conn->want |= FUSE_CAP_CACHE_SYMLINKS;
 #endif
@@ -164,6 +176,22 @@ df_ll_getattr(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi)
 		DFUSE_IE_STAT_ADD(inode, DS_GETATTR);
 	}
 
+	/* Check for stat-after-write/close.  On close a stat is performed so the first getattr
+	 * call can use the result of that.
+	 */
+	if (inode->ie_dfs->dfc_attr_timeout) {
+		double timeout;
+		dfuse_ie_cs_flush(inode);
+
+		if (dfuse_dc_cache_get_valid(inode, inode->ie_dfs->dfc_attr_timeout, &timeout)) {
+			if (inode->ie_dc.valid) {
+				DFUSE_IE_STAT_ADD(inode, DS_PRE_GETATTR);
+				inode->ie_dc.valid = false;
+				DFUSE_REPLY_ATTR_FORCE(inode, req, timeout);
+				return;
+			}
+		}
+	}
 	DFUSE_IE_WFLUSH(inode);
 
 	if (inode->ie_dfs->dfc_attr_timeout &&

src/client/dfuse/inval.c

@@ -344,7 +344,7 @@ ival_update_inode(struct dfuse_inode_entry *inode, double timeout)
 	if (S_ISDIR(inode->ie_stat.st_mode))
 		timeout += INVAL_DIRECTORY_GRACE;
 	else
-		timeout += INVAL_FILE_GRACE;
+		timeout = inode->ie_dfs->dfc_dentry_inval_time;
 
 	clock_gettime(CLOCK_MONOTONIC_COARSE, &now);
 
@@ -444,7 +444,7 @@ ival_bucket_dec_value(double timeout)
 }
 
 /* Ensure the correct buckets exist for a attached container.  Pools have a zero dentry timeout
- * so skip zero values
+ * so skip zero values.
  */
 int
 ival_add_cont_buckets(struct dfuse_cont *dfc)
@@ -457,7 +457,7 @@ ival_add_cont_buckets(struct dfuse_cont *dfc)
 	if (rc != 0)
 		goto out;
 	if (dfc->dfc_dentry_timeout != 0) {
-		rc = ival_bucket_add_value(dfc->dfc_dentry_timeout + INVAL_FILE_GRACE);
+		rc = ival_bucket_add_value(dfc->dfc_dentry_inval_time);
 		if (rc != 0)
 			ival_bucket_dec_value(dfc->dfc_dentry_dir_timeout + INVAL_DIRECTORY_GRACE);
 	}
@@ -473,7 +473,7 @@ ival_dec_cont_buckets(struct dfuse_cont *dfc)
 {
 	D_MUTEX_LOCK(&ival_lock);
 	if (dfc->dfc_dentry_timeout != 0)
-		ival_bucket_dec_value(dfc->dfc_dentry_timeout + INVAL_FILE_GRACE);
+		ival_bucket_dec_value(dfc->dfc_dentry_inval_time);
 	ival_bucket_dec_value(dfc->dfc_dentry_dir_timeout + INVAL_DIRECTORY_GRACE);
 	D_MUTEX_UNLOCK(&ival_lock);
 }

src/client/dfuse/ops/fgetattr.c

@@ -1,5 +1,5 @@
 /**
- * (C) Copyright 2016-2023 Intel Corporation.
+ * (C) Copyright 2016-2024 Intel Corporation.
  *
  * SPDX-License-Identifier: BSD-2-Clause-Patent
  */
@@ -10,14 +10,28 @@
 static void
 dfuse_cb_getattr_cb(struct dfuse_event *ev)
 {
+	struct dfuse_inode_entry *ie = ev->de_ie;
+
 	if (ev->de_ev.ev_error != 0) {
-		DFUSE_REPLY_ERR_RAW(ev->de_ie, ev->de_req, ev->de_ev.ev_error);
+		DFUSE_REPLY_ERR_RAW(ie, ev->de_req, ev->de_ev.ev_error);
 		D_GOTO(release, 0);
 	}
 
-	ev->de_attr.st_ino = ev->de_ie->ie_stat.st_ino;
+	ev->de_attr.st_ino = ie->ie_stat.st_ino;
+
+	ie->ie_stat = ev->de_attr;
 
-	ev->de_ie->ie_stat = ev->de_attr;
+	if ((ie->ie_dfs->dfc_data_timeout != 0) &&
+	    (dfuse_dcache_get_valid(ie, ie->ie_dfs->dfc_data_timeout))) {
+		/* This tries to match the code in fuse_change_attributes in fs/fuse/inode.c,
+		 * if the mtime or the size has changed then drop the data cache.
+		 */
+		if ((ie->ie_stat.st_size != ie->ie_dc.stat.st_size) ||
+		    (d_timediff_ns(&ie->ie_stat.st_mtim, &ie->ie_dc.stat.st_mtim) != 0)) {
+			DFUSE_TRA_DEBUG(ie, "Invalidating data cache");
+			dfuse_dcache_evict(ie);
+		}
+	}
 
 	DFUSE_REPLY_ATTR(ev->de_ie, ev->de_req, &ev->de_attr);
 release: