Update error handling

blockdevice/stats.go

@@ -497,8 +497,9 @@ func (fs FS) SysBlockDeviceIOStat(device string) (IODeviceStats, error) {
 			val, err = util.ReadHexFromFile(fs.sys.Path(sysBlockPath, device, sysDevicePath, file))
 			if err != nil {
 					return IODeviceStats{}, err
+			} else {
+				*p = val
 			}
-			*p = val
 	}
 	return ioDeviceStats, nil
 }

ext4/ext4.go

@@ -15,6 +15,7 @@
 package ext4
 
 import (
+	"fmt"
 	"strings"
 	"path/filepath"
 
@@ -23,8 +24,8 @@ import (
 )
 
 const (
-	sysPath        = "sys"
 	sysFSPath        = "fs"
+	sysFSExt4Path        = "ext4"
 )
 
 // Stats contains statistics for a single Btrfs filesystem.
@@ -79,24 +80,26 @@ func (fs FS) ProcStat() ([]*Stats, error) {
 
 	stats := make([]*Stats, 0, len(matches))
 	for _, m := range matches {
-			s := &Stats{}
-			for file, p := range map[string]*uint64{
-					"errors_count": &s.Errors,
-					"warning_count": &s.Warnings,
-					"msg_count": &s.Messages,
-			} {
-					var val uint64
-					val, err = util.ReadUintFromFile(fs.sys.Path(m, file))
-					if err != nil {
-							return nil, err
-					}
+		s := &Stats{}
+
+		// "*" used in glob above indicates the name of the filesystem.
+		name := filepath.Base(m)
+		s.Name = name
+		for file, p := range map[string]*uint64{
+				"errors_count": &s.Errors,
+				"warning_count": &s.Warnings,
+				"msg_count": &s.Messages,
+		} {
+				var val uint64
+				val, err = util.ReadUintFromFile(fs.sys.Path(sysFSPath, sysFSExt4Path, name, file))
+				if err != nil {
+						fmt.Errorf("failed to read ext4 stats from %s: %w", file, err)
+				} else {
 					*p = val
-			}
+				}
+		}
 
-			// "*" used in glob above indicates the name of the filesystem.
-			name := filepath.Base(filepath.Dir(filepath.Dir(m)))
-			s.Name = name
-			stats = append(stats, s)
+		stats = append(stats, s)
 	}
 
 	return stats, nil