From: Naohiro Aota <na...@elisp.net>
There are mutual exclusive mount options corresponding to
compression options. If we set these options at once, we get
improper messages and states, and a verbose message.
* Improper states
- We can't disable "compress forcing" with compress={zlib,lzo}
mount option.
====
# mount -o remount,compress-force=zlib,compress=lzo
[58852.210209] BTRFS info (device vda2): force zlib compression
(We should see "use lzo compression" here)
# mount | grep btrfs
/dev/vda2 on / type btrfs
(rw,relatime,seclabel,compress-force=lzo,space_cache)
(We should also change "compress-force=lzo" to "compress=lzo")
====
* Improper messages
- We don't see compression enabled message when we enables it
after disabling it.
====
# mount -o remount,compress=no,compress=zlib; dmesg -c
[ 4077.130625] BTRFS info (device vda2): btrfs: use no compression
(We should see "use zlib compression" here)
====
- We don't see any message when we change compression type.
====
# mount -o remount,compress=zlib,compress=lzo
(Since "BTRFS info" is at the beginning of this message, "btrfs: " is
verbose
and we don't need it.)
====
- We don't see datacow and/or datasum enabling message when we
enable compression.
====
# mount -o remount,nodatacow,nodatasum,compress
[58913.704536] BTRFS info (device vda2): setting nodatacow
(We should see "use zlib compression, setting datacow and datasum" here)
====
====
# mount -o remount,nodatasum,compress
[58950.529392] BTRFS info (device vda2): setting nodatasum
(We should see "use zlib compression, setting datasum" here)
====
* A verbose message
- We see verbose "btrfs: " prefix on disabling compression.
====
# mount -o remount,compress=zlib,compress=no
[58790.727788] BTRFS info (device vda2): btrfs: use no compression
("btrfs: " is verbose here. We don't need it, since we already
state this is btrfs with "BTRFS info")
====
This commit solves all these problems.
I separated the code in the following two parts:
a) Parse the options.
b) Set and clear flags of mount_opt and show proper messages.
I've confirmed that this patch doesn't cause any regression
by running the following script, which tests all combinations
of corresponding mount options (compress, compress-force,
datacow, and datasum).
=====================
#!/bin/bash
BTRFS_ROOT=/
states=(
compress=zlib,datacow,datasum
compress=lzo,datacow,datasum
compress-force=zlib,datacow,datasum
compress-force=lzo,datacow,datasum
compress=no,nodatacow,nodatasum
compress=no,datacow,nodatasum
compress=no,datacow,datasum
)
options=(
compress
compress=zlib
compress=lzo
compress=no
compress=badopt
compress-force
compress-force=zlib
compress-force=lzo
compress-force=no
compress-force=badopt
nodatacow
datacow
nodatasum
datasum
)
for s in ${states[@]}; do
for o in ${options[@]}; do
# set initial state
echo initial: mount -o remount,$s
mount -o remount,$s ${BTRFS_ROOT}
# mount with each option
echo mount -o remount,$o
dmesg -C
mount -o remount,$o ${BTRFS_ROOT}
echo dmesg:
dmesg -t | perl -ne 'if(/^BTRFS info \(device .+?\): (.+)$/){print
"\t$1\n"}'
echo -n 'mount options: '
grep -v rootfs /proc/mounts | \
awk "{if(\$2==\"${BTRFS_ROOT}\"){print \$4}}" | \
perl -ne '@a=split(/,/); for(@a){print "$_ "
if(/^compress(-force)?=|nodata(cow|sum)$/)}'
echo
echo
done
done
=====================
Signed-off-by: Naohiro Aota <na...@elisp.net>
Signed-off-by: Satoru Takeuchi <takeuchi_sat...@jp.fujitsu.com>
---
fs/btrfs/super.c | 57 +++++++++++++++++++++++++++++++++++++++-----------------
1 file changed, 40 insertions(+), 17 deletions(-)
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 03131c5..83433e15 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -401,6 +401,7 @@ int btrfs_parse_options(struct btrfs_root *root, char
*options)
char *compress_type;
bool compress_force = false;
bool compress = false;
+ unsigned long old_compress_type;
cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
if (cache_gen)
@@ -486,40 +487,62 @@ int btrfs_parse_options(struct btrfs_root *root, char
*options)
case Opt_compress:
case Opt_compress_type:
compress = true;
+ old_compress_type = info->compress_type;
if (token == Opt_compress ||
token == Opt_compress_force ||
strcmp(args[0].from, "zlib") == 0) {
compress_type = "zlib";
info->compress_type = BTRFS_COMPRESS_ZLIB;
- btrfs_set_opt(info->mount_opt, COMPRESS);
- btrfs_clear_opt(info->mount_opt, NODATACOW);
- btrfs_clear_opt(info->mount_opt, NODATASUM);
} else if (strcmp(args[0].from, "lzo") == 0) {
compress_type = "lzo";
info->compress_type = BTRFS_COMPRESS_LZO;
- btrfs_set_opt(info->mount_opt, COMPRESS);
- btrfs_clear_opt(info->mount_opt, NODATACOW);
- btrfs_clear_opt(info->mount_opt, NODATASUM);
btrfs_set_fs_incompat(info, COMPRESS_LZO);
} else if (strncmp(args[0].from, "no", 2) == 0) {
compress_type = "no";
- btrfs_clear_opt(info->mount_opt, COMPRESS);
- btrfs_clear_opt(info->mount_opt,
FORCE_COMPRESS);
- compress_force = false;
+ compress = compress_force = false;
} else {
ret = -EINVAL;
goto out;
}
- if (compress_force) {
- btrfs_set_and_info(root, FORCE_COMPRESS,
- "force %s compression",
- compress_type);
- } else if (compress) {
- if (!btrfs_test_opt(root, COMPRESS))
+ if (compress_force || compress) {
+ const char *method = "", *setting = "";
+
+ if ((info->compress_type != old_compress_type)
||
+ (compress_force &&
+ !btrfs_test_opt(root, FORCE_COMPRESS)) ||
+ (!compress_force &&
+ btrfs_test_opt(root, FORCE_COMPRESS)) ||
+ (compress && !btrfs_test_opt(root,
COMPRESS))) {
+ method = compress_force?"force":"use";
+ }
+
+ if (btrfs_test_opt(root, NODATACOW))
+ setting = ", setting datacow and
datasum";
+ else if (btrfs_test_opt(root, NODATASUM))
+ setting = ", setting datasum";
+
+ if (strcmp(method, "") != 0) {
btrfs_info(root->fs_info,
- "btrfs: use %s compression",
- compress_type);
+ "%s %s compression%s",
+ method, compress_type,
+ setting);
+ }
+ if (compress_force) {
+ btrfs_set_opt(info->mount_opt,
+ FORCE_COMPRESS);
+ } else {
+ btrfs_clear_opt(info->mount_opt,
+ FORCE_COMPRESS);
+ }
+ btrfs_set_opt(info->mount_opt, COMPRESS);
+ btrfs_clear_opt(info->mount_opt, NODATACOW);
+ btrfs_clear_opt(info->mount_opt, NODATASUM);
+ } else {
+ btrfs_clear_and_info(root, COMPRESS,
+ "use no compression");
+ btrfs_clear_opt(info->mount_opt,
+ FORCE_COMPRESS);
}
break;
case Opt_ssd:
-- 1.8.3.1
--
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