Defragging an executable conflicts both way with it being run, resulting in
ETXTBSY. This either makes defrag fail or prevents the program from being
executed.
Kernels 4.19-rc1 and later allow defragging files you could have possibly
opened rw, even if the passed descriptor is ro (commit 616d374efa23).
Signed-off-by: Adam Borowski <kilob...@angband.pl>
---
v2: more eloquent description; root can't defrag RO on old kernels (unlike
dedupe)
v3: more eloquentier description; s/defrag_ro/defrag_open_mode/
cmds-filesystem.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/cmds-filesystem.c b/cmds-filesystem.c
index d1af21ee..c67bf5da 100644
--- a/cmds-filesystem.c
+++ b/cmds-filesystem.c
@@ -26,6 +26,7 @@
#include <ftw.h>
#include <mntent.h>
#include <linux/limits.h>
+#include <linux/version.h>
#include <getopt.h>
#include <btrfsutil.h>
@@ -39,12 +40,14 @@
#include "list_sort.h"
#include "disk-io.h"
#include "help.h"
+#include "fsfeatures.h"
/*
* for btrfs fi show, we maintain a hash of fsids we've already printed.
* This way we don't print dups if a given FS is mounted more than once.
*/
static struct seen_fsid *seen_fsid_hash[SEEN_FSID_HASH_SIZE] = {NULL,};
+static mode_t defrag_open_mode = O_RDONLY;
static const char * const filesystem_cmd_group_usage[] = {
"btrfs filesystem [<group>] <command> [<args>]",
@@ -878,7 +881,7 @@ static int defrag_callback(const char *fpath, const struct
stat *sb,
if ((typeflag == FTW_F) && S_ISREG(sb->st_mode)) {
if (defrag_global_verbose)
printf("%s\n", fpath);
- fd = open(fpath, O_RDWR);
+ fd = open(fpath, defrag_open_mode);
if (fd < 0) {
goto error;
}
@@ -915,6 +918,9 @@ static int cmd_filesystem_defrag(int argc, char **argv)
int compress_type = BTRFS_COMPRESS_NONE;
DIR *dirstream;
+ if (get_running_kernel_version() < KERNEL_VERSION(4,19,0))
+ defrag_open_mode = O_RDWR;
+
/*
* Kernel has a different default (256K) that is supposed to be safe,
* but it does not defragment very well. The 32M will likely lead to
@@ -1015,7 +1021,7 @@ static int cmd_filesystem_defrag(int argc, char **argv)
int defrag_err = 0;
dirstream = NULL;
- fd = open_file_or_dir(argv[i], &dirstream);
+ fd = open_file_or_dir3(argv[i], &dirstream, defrag_open_mode);
if (fd < 0) {
error("cannot open %s: %m", argv[i]);
ret = -errno;
--
2.19.1
