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Commit 66acdcf4 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: add debugging /proc file showing file system options 



Now that /proc/mounts is consistently showing only those mount options
which need to be specified in /etc/fstab or on the mount command line,
it is useful to have file which shows exactly which file system
options are enabled.  This can be useful when debugging a user
problem.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 5a916be1

fs/ext4/super.c

+54 −17
Original line number Diff line number Diff line
@@ -847,6 +847,7 @@ static void ext4_put_super(struct super_block *sb) 
		ext4_commit_super(sb, 1);

	}

	if (sbi->s_proc) {

		remove_proc_entry("options", sbi->s_proc);

		remove_proc_entry(sb->s_id, ext4_proc_root);

	}

	kobject_del(&sbi->s_kobj);
@@ -1683,16 +1684,17 @@ static const char *token2str(int token) 
 *  - it's set to a non-default value OR

 *  - if the per-sb default is different from the global default

 */

static int ext4_show_options(struct seq_file *seq, struct dentry *root)

static int _ext4_show_options(struct seq_file *seq, struct super_block *sb,

			      int nodefs)

{

	int def_errors;

	struct super_block *sb = root->d_sb;

	struct ext4_sb_info *sbi = EXT4_SB(sb);

	struct ext4_super_block *es = sbi->s_es;

	int def_errors, def_mount_opt = nodefs ? 0 : sbi->s_def_mount_opt;

	const struct mount_opts *m;

	char sep = nodefs ? '\n' : ',';



#define SEQ_OPTS_PUTS(str) seq_printf(seq, "," str)

#define SEQ_OPTS_PRINT(str, arg) seq_printf(seq, "," str, arg)

#define SEQ_OPTS_PUTS(str) seq_printf(seq, "%c" str, sep)

#define SEQ_OPTS_PRINT(str, arg) seq_printf(seq, "%c" str, sep, arg)



	if (sbi->s_sb_block != 1)

		SEQ_OPTS_PRINT("sb=%llu", sbi->s_sb_block);
@@ -1702,7 +1704,7 @@ static int ext4_show_options(struct seq_file *seq, struct dentry *root) 
		if (((m->flags & (MOPT_SET|MOPT_CLEAR)) == 0) ||

		    (m->flags & MOPT_CLEAR_ERR))

			continue;

		if (!(m->mount_opt & (sbi->s_mount_opt ^ sbi->s_def_mount_opt)))

		if (!(m->mount_opt & (sbi->s_mount_opt ^ def_mount_opt)))

			continue; /* skip if same as the default */

		if ((want_set &&

		     (sbi->s_mount_opt & m->mount_opt) != m->mount_opt) ||
@@ -1711,30 +1713,30 @@ static int ext4_show_options(struct seq_file *seq, struct dentry *root) 
		SEQ_OPTS_PRINT("%s", token2str(m->token));

	}



	if (sbi->s_resuid != EXT4_DEF_RESUID ||

	if (nodefs || sbi->s_resuid != EXT4_DEF_RESUID ||

	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID)

		SEQ_OPTS_PRINT("resuid=%u", sbi->s_resuid);

	if (sbi->s_resgid != EXT4_DEF_RESGID ||

	if (nodefs || sbi->s_resgid != EXT4_DEF_RESGID ||

	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID)

		SEQ_OPTS_PRINT("resgid=%u", sbi->s_resgid);

	def_errors = le16_to_cpu(es->s_errors);

	def_errors = nodefs ? -1 : le16_to_cpu(es->s_errors);

	if (test_opt(sb, ERRORS_RO) && def_errors != EXT4_ERRORS_RO)

		SEQ_OPTS_PUTS("errors=remount-ro");

	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)

		SEQ_OPTS_PUTS("errors=continue");

	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)

		SEQ_OPTS_PUTS("errors=panic");

	if (sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ)

	if (nodefs || sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ)

		SEQ_OPTS_PRINT("commit=%lu", sbi->s_commit_interval / HZ);

	if (sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME)

	if (nodefs || sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME)

		SEQ_OPTS_PRINT("min_batch_time=%u", sbi->s_min_batch_time);

	if (sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME)

	if (nodefs || sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME)

		SEQ_OPTS_PRINT("max_batch_time=%u", sbi->s_max_batch_time);

	if (sb->s_flags & MS_I_VERSION)

		SEQ_OPTS_PUTS("i_version");

	if (sbi->s_stripe)

	if (nodefs || sbi->s_stripe)

		SEQ_OPTS_PRINT("stripe=%lu", sbi->s_stripe);

	if (EXT4_MOUNT_DATA_FLAGS & (sbi->s_mount_opt ^ sbi->s_def_mount_opt)) {

	if (EXT4_MOUNT_DATA_FLAGS & (sbi->s_mount_opt ^ def_mount_opt)) {

		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)

			SEQ_OPTS_PUTS("data=journal");

		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
@@ -1742,18 +1744,48 @@ static int ext4_show_options(struct seq_file *seq, struct dentry *root) 
		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)

			SEQ_OPTS_PUTS("data=writeback");

	}

	if (sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)

	if (nodefs ||

	    sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)

		SEQ_OPTS_PRINT("inode_readahead_blks=%u",

			       sbi->s_inode_readahead_blks);



	if (test_opt(sb, INIT_INODE_TABLE) &&

	    (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT))

	if (nodefs || (test_opt(sb, INIT_INODE_TABLE) &&

		       (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT)))

		SEQ_OPTS_PRINT("init_itable=%u", sbi->s_li_wait_mult);



	ext4_show_quota_options(seq, sb);

	return 0;

}



static int ext4_show_options(struct seq_file *seq, struct dentry *root)

{

	return _ext4_show_options(seq, root->d_sb, 0);

}



static int options_seq_show(struct seq_file *seq, void *offset)

{

	struct super_block *sb = seq->private;

	int rc;



	seq_puts(seq, (sb->s_flags & MS_RDONLY) ? "ro" : "rw");

	rc = _ext4_show_options(seq, sb, 1);

	seq_puts(seq, "\n");

	return rc;

}



static int options_open_fs(struct inode *inode, struct file *file)

{

	return single_open(file, options_seq_show, PDE(inode)->data);

}



static const struct file_operations ext4_seq_options_fops = {

	.owner = THIS_MODULE,

	.open = options_open_fs,

	.read = seq_read,

	.llseek = seq_lseek,

	.release = single_release,

};



static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,

			    int read_only)

{
@@ -3350,6 +3382,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) 
	if (ext4_proc_root)

		sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);



	if (sbi->s_proc)

		proc_create_data("options", S_IRUGO, sbi->s_proc,

				 &ext4_seq_options_fops, sb);



	bgl_lock_init(sbi->s_blockgroup_lock);



	for (i = 0; i < db_count; i++) {
@@ -3674,6 +3710,7 @@ failed_mount2: 
	ext4_kvfree(sbi->s_group_desc);

failed_mount:

	if (sbi->s_proc) {

		remove_proc_entry("options", sbi->s_proc);

		remove_proc_entry(sb->s_id, ext4_proc_root);

	}

#ifdef CONFIG_QUOTA