Add nodiscard mount option to disable discard with remount option.
Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
---
changelog:
v2: Add nodiscard mount option.
---
Documentation/filesystems/btrfs.txt | 7 +++++--
fs/btrfs/super.c | 5 +++++
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/Documentation/filesystems/btrfs.txt b/Documentation/filesystems/btrfs.txt
index aab54e9..344e67f 100644
--- a/Documentation/filesystems/btrfs.txt
+++ b/Documentation/filesystems/btrfs.txt
@@ -101,9 +101,12 @@ Options with (*) are default options and will not show in the mount options.
can be avoided. Especially useful when trying to mount a multi-device
setup as root. May be specified multiple times for multiple devices.
+ nodiscard(*)
discard
- Issue frequent commands to let the block device reclaim space freed by
- the filesystem. This is useful for SSD devices, thinly provisioned
+ Disable/enable discard mount option.
+ Discard issues frequent commands to let the block device reclaim space
+ freed by the filesystem.
+ This is useful for SSD devices, thinly provisioned
LUNs and virtual machine images, but may have a significant
performance impact. (The fstrim command is also available to
initiate batch trims from userspace).
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index b408d05..3ab11d4 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -324,6 +324,7 @@ enum {
Opt_check_integrity, Opt_check_integrity_including_extent_data,
Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nocheck_integrity,
+ Opt_nodiscard,
Opt_err,
};
@@ -351,6 +352,7 @@ static match_table_t tokens = {
{Opt_flushoncommit, "flushoncommit"},
{Opt_ratio, "metadata_ratio=%d"},
{Opt_discard, "discard"},
+ {Opt_nodiscard, "nodiscard"},
{Opt_space_cache, "space_cache"},
{Opt_clear_cache, "clear_cache"},
{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
@@ -576,6 +578,9 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
case Opt_discard:
btrfs_set_opt(info->mount_opt, DISCARD);
break;
+ case Opt_nodiscard:
+ btrfs_clear_opt(info->mount_opt, DISCARD);
+ break;
case Opt_space_cache:
btrfs_set_opt(info->mount_opt, SPACE_CACHE);
break;
--
1.8.5.2
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