From: Timo Sirainen <timo.sirainen@dovecot.fi>
Date: Sat, 23 Jul 2016 16:02:29 +0000 (-0400)
Subject: lib-fs: Added fs_get_nlinks()
X-Git-Tag: 2.3.0.rc1~3276
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a63cd84128875485e40ed804dbf0b0945526989c;p=thirdparty%2Fdovecot%2Fcore.git

lib-fs: Added fs_get_nlinks()

Although fs_stat() could return this, its caller can't indicate whether
it actually wants the link count. Usually fs_stat() is used only to get
the file's size. In some backends it's not cheap to get the link count,
so adding this function allows the caller to explicitly ask for it.
---

diff --git a/src/lib-fs/fs-api-private.h b/src/lib-fs/fs-api-private.h
index 28f2c4ad9a..0d71a9a2e5 100644
--- a/src/lib-fs/fs-api-private.h
+++ b/src/lib-fs/fs-api-private.h
@@ -69,6 +69,7 @@ struct fs_vfuncs {
 	int (*iter_deinit)(struct fs_iter *iter);
 
 	bool (*switch_ioloop)(struct fs *fs);
+	int (*get_nlinks)(struct fs_file *file, nlink_t *nlinks_r);
 };
 
 struct fs {
diff --git a/src/lib-fs/fs-api.c b/src/lib-fs/fs-api.c
index bac5d16121..e53059348c 100644
--- a/src/lib-fs/fs-api.c
+++ b/src/lib-fs/fs-api.c
@@ -848,6 +848,33 @@ int fs_stat(struct fs_file *file, struct stat *st_r)
 	return ret;
 }
 
+int fs_get_nlinks(struct fs_file *file, nlink_t *nlinks_r)
+{
+	int ret;
+
+	if (file->fs->v.get_nlinks == NULL) {
+		struct stat st;
+
+		if (fs_stat(file, &st) < 0)
+			return -1;
+		*nlinks_r = st.st_nlink;
+		return 0;
+	}
+
+	if (!file->read_or_prefetch_counted &&
+	    !file->lookup_metadata_counted && !file->stat_counted) {
+		file->stat_counted = TRUE;
+		file->fs->stats.stat_count++;
+		fs_file_timing_start(file, FS_OP_STAT);
+	}
+	T_BEGIN {
+		ret = file->fs->v.get_nlinks(file, nlinks_r);
+	} T_END;
+	if (!(ret < 0 && errno == EAGAIN))
+		fs_file_timing_end(file, FS_OP_STAT);
+	return ret;
+}
+
 int fs_default_copy(struct fs_file *src, struct fs_file *dest)
 {
 	/* we're going to be counting this as read+write, so remove the
diff --git a/src/lib-fs/fs-api.h b/src/lib-fs/fs-api.h
index 1e42504d5c..cf285b1716 100644
--- a/src/lib-fs/fs-api.h
+++ b/src/lib-fs/fs-api.h
@@ -303,6 +303,10 @@ int fs_delete(struct fs_file *file);
 /* Returns 0 if ok, -1 if error occurred (e.g. errno=ENOENT).
    All fs backends may not support all stat fields. */
 int fs_stat(struct fs_file *file, struct stat *st_r);
+/* Get number of links to the file. This is the same as using fs_stat()'s
+   st_nlinks field, except not all backends support returning it via fs_stat().
+   Returns 0 if ok, -1 if error occurred. */
+int fs_get_nlinks(struct fs_file *file, nlink_t *nlinks_r);
 /* Copy an object with possibly updated metadata. Destination parent
    directories are created automatically. Returns 0 if ok, -1 if error
    occurred. */
diff --git a/src/lib-fs/fs-dict.c b/src/lib-fs/fs-dict.c
index 3b0ba32ea5..035005a758 100644
--- a/src/lib-fs/fs-dict.c
+++ b/src/lib-fs/fs-dict.c
@@ -323,6 +323,7 @@ const struct fs fs_class_dict = {
 		fs_dict_iter_init,
 		fs_dict_iter_next,
 		fs_dict_iter_deinit,
+		NULL,
 		NULL
 	}
 };
diff --git a/src/lib-fs/fs-metawrap.c b/src/lib-fs/fs-metawrap.c
index 3432df6174..4b6519a2cb 100644
--- a/src/lib-fs/fs-metawrap.c
+++ b/src/lib-fs/fs-metawrap.c
@@ -496,6 +496,7 @@ const struct fs fs_class_metawrap = {
 		fs_wrapper_iter_init,
 		fs_wrapper_iter_next,
 		fs_wrapper_iter_deinit,
-		NULL
+		NULL,
+		fs_wrapper_get_nlinks,
 	}
 };
diff --git a/src/lib-fs/fs-posix.c b/src/lib-fs/fs-posix.c
index a28ce22d9c..a4baeae36d 100644
--- a/src/lib-fs/fs-posix.c
+++ b/src/lib-fs/fs-posix.c
@@ -884,6 +884,7 @@ const struct fs fs_class_posix = {
 		fs_posix_iter_init,
 		fs_posix_iter_next,
 		fs_posix_iter_deinit,
-		NULL
+		NULL,
+		NULL,
 	}
 };
diff --git a/src/lib-fs/fs-randomfail.c b/src/lib-fs/fs-randomfail.c
index e133bad3f8..484a12328b 100644
--- a/src/lib-fs/fs-randomfail.c
+++ b/src/lib-fs/fs-randomfail.c
@@ -446,6 +446,17 @@ static int fs_randomfail_stat(struct fs_file *_file, struct stat *st_r)
 	return fs_file_random_fail_end(file, ret, FS_OP_STAT);
 }
 
+static int fs_randomfail_get_nlinks(struct fs_file *_file, nlink_t *nlinks_r)
+{
+	struct randomfail_fs_file *file = (struct randomfail_fs_file *)_file;
+	int ret;
+
+	if (fs_file_random_fail_begin(file, FS_OP_STAT))
+		return -1;
+	ret = fs_get_nlinks(file->super, nlinks_r);
+	return fs_file_random_fail_end(file, ret, FS_OP_STAT);
+}
+
 static int fs_randomfail_copy(struct fs_file *_src, struct fs_file *_dest)
 {
 	struct randomfail_fs_file *src = (struct randomfail_fs_file *)_src;
@@ -566,6 +577,7 @@ const struct fs fs_class_randomfail = {
 		fs_randomfail_iter_init,
 		fs_randomfail_iter_next,
 		fs_randomfail_iter_deinit,
-		NULL
+		NULL,
+		fs_randomfail_get_nlinks,
 	}
 };
diff --git a/src/lib-fs/fs-sis-queue.c b/src/lib-fs/fs-sis-queue.c
index 588776e45f..1e38d643db 100644
--- a/src/lib-fs/fs-sis-queue.c
+++ b/src/lib-fs/fs-sis-queue.c
@@ -200,6 +200,7 @@ const struct fs fs_class_sis_queue = {
 		fs_wrapper_iter_init,
 		NULL,
 		NULL,
-		NULL
+		NULL,
+		fs_wrapper_get_nlinks,
 	}
 };
diff --git a/src/lib-fs/fs-sis.c b/src/lib-fs/fs-sis.c
index 143463f065..eb947c101f 100644
--- a/src/lib-fs/fs-sis.c
+++ b/src/lib-fs/fs-sis.c
@@ -351,6 +351,7 @@ const struct fs fs_class_sis = {
 		fs_wrapper_iter_init,
 		NULL,
 		NULL,
-		NULL
+		NULL,
+		fs_wrapper_get_nlinks,
 	}
 };
diff --git a/src/lib-fs/fs-test.c b/src/lib-fs/fs-test.c
index d35caf5366..cf912b0b9c 100644
--- a/src/lib-fs/fs-test.c
+++ b/src/lib-fs/fs-test.c
@@ -417,6 +417,7 @@ const struct fs fs_class_test = {
 		fs_test_iter_init,
 		fs_test_iter_next,
 		fs_test_iter_deinit,
-		NULL
+		NULL,
+		NULL,
 	}
 };
diff --git a/src/lib-fs/fs-wrapper.c b/src/lib-fs/fs-wrapper.c
index 8d90561499..524f113131 100644
--- a/src/lib-fs/fs-wrapper.c
+++ b/src/lib-fs/fs-wrapper.c
@@ -108,6 +108,11 @@ int fs_wrapper_stat(struct fs_file *file, struct stat *st_r)
 	return fs_stat(file->parent, st_r);
 }
 
+int fs_wrapper_get_nlinks(struct fs_file *file, nlink_t *nlinks_r)
+{
+	return fs_get_nlinks(file->parent, nlinks_r);
+}
+
 int fs_wrapper_copy(struct fs_file *src, struct fs_file *dest)
 {
 	if (src != NULL)
diff --git a/src/lib-fs/fs-wrapper.h b/src/lib-fs/fs-wrapper.h
index 992b020070..c6d99da069 100644
--- a/src/lib-fs/fs-wrapper.h
+++ b/src/lib-fs/fs-wrapper.h
@@ -24,6 +24,7 @@ int fs_wrapper_lock(struct fs_file *file, unsigned int secs,
 void fs_wrapper_unlock(struct fs_lock *_lock);
 int fs_wrapper_exists(struct fs_file *file);
 int fs_wrapper_stat(struct fs_file *file, struct stat *st_r);
+int fs_wrapper_get_nlinks(struct fs_file *file, nlink_t *nlinks_r);
 int fs_wrapper_copy(struct fs_file *src, struct fs_file *dest);
 int fs_wrapper_rename(struct fs_file *src, struct fs_file *dest);
 int fs_wrapper_delete(struct fs_file *file);
diff --git a/src/plugins/fs-compress/fs-compress.c b/src/plugins/fs-compress/fs-compress.c
index e09cb5d504..e1e3ceafa3 100644
--- a/src/plugins/fs-compress/fs-compress.c
+++ b/src/plugins/fs-compress/fs-compress.c
@@ -254,6 +254,7 @@ const struct fs fs_class_compress = {
 		fs_wrapper_iter_init,
 		fs_wrapper_iter_next,
 		fs_wrapper_iter_deinit,
-		NULL
+		NULL,
+		fs_wrapper_get_nlinks
 	}
 };