Thread (3 messages) flat view 3 messages, 2 authors, 2011-08-18

Re: [PATCH v2 05/12] e4defrag: Add force option for e4defrag

From: Andreas Dilger <hidden>
Date: 2011-08-17 16:30:39

On 2011-08-17, at 1:47 AM, Kazuya Mio [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Currently, e4defrag calls EXT4_IOC_MOVE_EXT ioctl if the fragmentation score
of a donor file is zero. However, it is difficult sometimes to create the file
that has the average of 4096 blocks per extent. We can use e4defrag -F to defrag
in this case.

Signed-off-by: Kazuya Mio <redacted>
---
misc/e4defrag.8.in |    5 ++++-
misc/e4defrag.c    |   14 ++++++++++----
2 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/misc/e4defrag.8.in b/misc/e4defrag.8.in
index 81adc29..ede7455 100644
--- a/misc/e4defrag.8.in
+++ b/misc/e4defrag.8.in
@@ -4,7 +4,7 @@ e4defrag \- online defragmenter for ext4 filesystem
.SH SYNOPSIS
.B e4defrag
[
-.B \-v
+.B \-Fv
]
.I target
\&...
@@ -31,6 +31,9 @@ gets the mount point of it and reduces fragmentation of all files in this mount
point.
.SH OPTIONS
.TP
+.B \-F
+Force defrag if the fragmentation gets better.
+.TP
.B \-v
Print error messages and the fragmentation count before and after defrag for
each file.
diff --git a/misc/e4defrag.c b/misc/e4defrag.c
index 44d54f3..64b1474 100644
--- a/misc/e4defrag.c
+++ b/misc/e4defrag.c
@@ -80,6 +80,7 @@
/* The mode of defrag */
#define DETAIL            0x01
+#define FORCE            0x02

#define DEVNAME            0
#define DIRNAME            1
@@ -107,7 +108,7 @@
/* The following macros are error message */
#define MSG_USAGE        \
-"Usage    : e4defrag [-v] file...| directory...| device...\n"
+"Usage    : e4defrag [-Fv] file...| directory...| device...\n"

#define NGMSG_EXT4        "Filesystem is not ext4 filesystem"
#define NGMSG_FILE_EXTENT    "Failed to get file extents"
@@ -1153,7 +1154,8 @@ check_improvement:
       extents_before_defrag += file_frags_start;
   }

-    if (!orig_score || donor_score) {
+    if (!orig_score || (donor_score && !(mode_flag & FORCE)) ||
+            (orig_score <= donor_score && (mode_flag & FORCE))) {
It is confusing in conditionals like this when integer variables are treated as boolean values. It would be more clear to compare the orig_score and donor_score to zero.

        if (orig_score == 0 || (donor_score > 0 && !(mode_flag & FORCE)) ||
            (orig_score <= donor_score && (mode_flag & FORCE))) {

To be honest, I still can't understand the above logic. I would think it is enough to check:

        if (orig_score < donor_score && !(mode_flag & FORCE))) {

so that the file is not defragged if the score would get worse, but "force" means it is always moved.
 
printf("\033[79;0H\033[K[%u/%u]%s:\t%3d%%",
It would be nice if the color terminal output was optional (maybe only on by default for tty output).  This is not typical for other e2fsprogs utilities, and makes a mess of logs being kept of the output. 
quoted hunk ↗ jump to hunk
           defraged_file_count, total_count, file, 100);
       if (mode_flag & DETAIL)
@@ -1231,8 +1233,12 @@ int main(int argc, char *argv[])
   if (argc == 1)
       goto out;

-    while ((opt = getopt(argc, argv, "v")) != EOF) {
+    while ((opt = getopt(argc, argv, "Fv")) != EOF) {
       switch (opt) {
+        case 'F':
+            /* Force defrag if the fragmentation gets better */
+            mode_flag |= FORCE;
Should this comment be "Force defrag if the fragmentation gets _worse_"?
quoted hunk ↗ jump to hunk
+            break;
       case 'v':
           mode_flag |= DETAIL;
           break;
@@ -1245,7 +1251,7 @@ int main(int argc, char *argv[])
       goto out;

   current_uid = getuid();
-    threshold = DEFAULT_THRESHOLD;
+    threshold = (mode_flag & FORCE) ? ~0U : DEFAULT_THRESHOLD;

   /* Main process */
   for (i = optind; i < argc; i++) {
--
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