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Commit 802d3177 authored by Ryusuke Konishi's avatar Ryusuke Konishi
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nilfs2: add nodiscard mount option 



Nilfs has "discard" mount option which issues discard/TRIM commands to
underlying block device, but it lacks a complementary option and has
no way to disable the feature through remount.

This adds "nodiscard" option to resolve this imbalance.

Signed-off-by: default avatarRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
parent 773bc4f3

Documentation/filesystems/nilfs2.txt

+4 −3
Original line number Diff line number Diff line
@@ -77,9 +77,10 @@ norecovery Disable recovery of the filesystem on mount. 
			This disables every write access on the device for

			read-only mounts or snapshots.  This option will fail

			for r/w mounts on an unclean volume.

discard			Issue discard/TRIM commands to the underlying block

			device when blocks are freed.  This is useful for SSD

			devices and sparse/thinly-provisioned LUNs.

discard			This enables/disables the use of discard/TRIM commands.

nodiscard(*)		The discard/TRIM commands are sent to the underlying

			block device when blocks are freed.  This is useful

			for SSD devices and sparse/thinly-provisioned LUNs.



NILFS2 usage

============

fs/nilfs2/super.c

+5 −1
Original line number Diff line number Diff line
@@ -604,7 +604,7 @@ static const struct export_operations nilfs_export_ops = { 
enum {

	Opt_err_cont, Opt_err_panic, Opt_err_ro,

	Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,

	Opt_discard, Opt_err,

	Opt_discard, Opt_nodiscard, Opt_err,

};



static match_table_t tokens = {
@@ -617,6 +617,7 @@ static match_table_t tokens = { 
	{Opt_order, "order=%s"},

	{Opt_norecovery, "norecovery"},

	{Opt_discard, "discard"},

	{Opt_nodiscard, "nodiscard"},

	{Opt_err, NULL}

};
@@ -676,6 +677,9 @@ static int parse_options(char *options, struct super_block *sb) 
		case Opt_discard:

			nilfs_set_opt(sbi, DISCARD);

			break;

		case Opt_nodiscard:

			nilfs_clear_opt(sbi, DISCARD);

			break;

		default:

			printk(KERN_ERR

			       "NILFS: Unrecognized mount option \"%s\"\n", p);