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Commit b3881f74 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: Add mount option to set kjournald's I/O priority 



Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Cc: Jens Axboe <jens.axboe@oracle.com>
parent 40a1984d

Documentation/filesystems/ext4.txt

+7 −0
Original line number Diff line number Diff line
@@ -308,6 +308,13 @@ min_batch_time=usec This parameter sets the commit time (as 
			multi-threaded, synchronous workloads on very

			fast disks, at the cost of increasing latency.



journal_ioprio=prio	The I/O priority (from 0 to 7, where 0 is the

			highest priorty) which should be used for I/O

			operations submitted by kjournald2 during a

			commit operation.  This defaults to 3, which is

			a slightly higher priority than the default I/O

			priority.



Data Mode

=========

There are 3 different data modes:

fs/ext4/super.c

+25 −4
Original line number Diff line number Diff line
@@ -1013,7 +1013,7 @@ enum { 
	Opt_ignore, Opt_barrier, Opt_err, Opt_resize, Opt_usrquota,

	Opt_grpquota, Opt_extents, Opt_noextents, Opt_i_version,

	Opt_stripe, Opt_delalloc, Opt_nodelalloc,

	Opt_inode_readahead_blks

	Opt_inode_readahead_blks, Opt_journal_ioprio

};



static const match_table_t tokens = {
@@ -1074,6 +1074,7 @@ static const match_table_t tokens = { 
	{Opt_delalloc, "delalloc"},

	{Opt_nodelalloc, "nodelalloc"},

	{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},

	{Opt_journal_ioprio, "journal_ioprio=%u"},

	{Opt_err, NULL},

};
@@ -1098,8 +1099,11 @@ static ext4_fsblk_t get_sb_block(void **data) 
	return sb_block;

}



#define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))



static int parse_options(char *options, struct super_block *sb,

			 unsigned long *journal_devnum,

			 unsigned int *journal_ioprio,

			 ext4_fsblk_t *n_blocks_count, int is_remount)

{

	struct ext4_sb_info *sbi = EXT4_SB(sb);
@@ -1492,6 +1496,14 @@ static int parse_options(char *options, struct super_block *sb, 
				return 0;

			sbi->s_inode_readahead_blks = option;

			break;

		case Opt_journal_ioprio:

			if (match_int(&args[0], &option))

				return 0;

			if (option < 0 || option > 7)

				break;

			*journal_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE,

							    option);

			break;

		default:

			printk(KERN_ERR

			       "EXT4-fs: Unrecognized mount option \"%s\" "
@@ -2035,6 +2047,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) 
	int features;

	__u64 blocks_count;

	int err;

	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;



	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);

	if (!sbi)
@@ -2141,7 +2154,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) 
	set_opt(sbi->s_mount_opt, DELALLOC);





	if (!parse_options((char *) data, sb, &journal_devnum, NULL, 0))

	if (!parse_options((char *) data, sb, &journal_devnum,

			   &journal_ioprio, NULL, 0))

		goto failed_mount;



	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
@@ -2506,6 +2520,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) 
	default:

		break;

	}

	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);



no_journal:
@@ -3127,6 +3142,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) 
	unsigned long old_sb_flags;

	struct ext4_mount_options old_opts;

	ext4_group_t g;

	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;

	int err;

#ifdef CONFIG_QUOTA

	int i;
@@ -3145,11 +3161,14 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) 
	for (i = 0; i < MAXQUOTAS; i++)

		old_opts.s_qf_names[i] = sbi->s_qf_names[i];

#endif

	if (sbi->s_journal && sbi->s_journal->j_task->io_context)

		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;



	/*

	 * Allow the "check" option to be passed as a remount option.

	 */

	if (!parse_options(data, sb, NULL, &n_blocks_count, 1)) {

	if (!parse_options(data, sb, NULL, &journal_ioprio,

			   &n_blocks_count, 1)) {

		err = -EINVAL;

		goto restore_opts;

	}
@@ -3162,8 +3181,10 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) 


	es = sbi->s_es;



	if (sbi->s_journal)

	if (sbi->s_journal) {

		ext4_init_journal_params(sb, sbi->s_journal);

		set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);

	}



	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY) ||

		n_blocks_count > ext4_blocks_count(es)) {

fs/ioprio.c

+2 −1
Original line number Diff line number Diff line
@@ -27,7 +27,7 @@ 
#include <linux/security.h>

#include <linux/pid_namespace.h>



static int set_task_ioprio(struct task_struct *task, int ioprio)

int set_task_ioprio(struct task_struct *task, int ioprio)

{

	int err;

	struct io_context *ioc;
@@ -70,6 +70,7 @@ static int set_task_ioprio(struct task_struct *task, int ioprio) 
	task_unlock(task);

	return err;

}

EXPORT_SYMBOL_GPL(set_task_ioprio);



asmlinkage long sys_ioprio_set(int which, int who, int ioprio)

{

include/linux/ioprio.h

+2 −0
Original line number Diff line number Diff line
@@ -86,4 +86,6 @@ static inline int task_nice_ioclass(struct task_struct *task) 
 */

extern int ioprio_best(unsigned short aprio, unsigned short bprio);



extern int set_task_ioprio(struct task_struct *task, int ioprio);



#endif