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Message-Id: <1330916905-5976-9-git-send-email-tytso@mit.edu>
Date: Sun, 4 Mar 2012 22:08:23 -0500
From: Theodore Ts'o <tytso@....edu>
To: Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc: Theodore Ts'o <tytso@....edu>
Subject: [PATCH 09/11] 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: "Theodore Ts'o" <tytso@....edu>
---
fs/ext4/super.c | 71 +++++++++++++++++++++++++++++++++++++++++-------------
1 files changed, 54 insertions(+), 17 deletions(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 7082869..27d490d 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -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
--
1.7.9.107.g97f9a
--
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