ext4: Add sysfs support
Add basic sysfs support so that information about the mounted
filesystem and various tuning parameters can be accessed via
/sys/fs/ext4/<dev>/*.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 30fc27c..2883d43 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -35,6 +35,7 @@
#include <linux/quotaops.h>
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
+#include <linux/ctype.h>
#include <linux/marker.h>
#include <linux/log2.h>
#include <linux/crc16.h>
@@ -48,6 +49,7 @@
#include "group.h"
struct proc_dir_entry *ext4_proc_root;
+static struct kset *ext4_kset;
static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
unsigned long journal_devnum);
@@ -580,6 +582,7 @@
remove_proc_entry("inode_readahead_blks", sbi->s_proc);
remove_proc_entry(sb->s_id, ext4_proc_root);
}
+ kobject_del(&sbi->s_kobj);
for (i = 0; i < sbi->s_gdb_count; i++)
brelse(sbi->s_group_desc[i]);
@@ -615,6 +618,16 @@
ext4_blkdev_remove(sbi);
}
sb->s_fs_info = NULL;
+ /*
+ * Now that we are completely done shutting down the
+ * superblock, we need to actually destroy the kobject.
+ */
+ unlock_kernel();
+ unlock_super(sb);
+ kobject_put(&sbi->s_kobj);
+ wait_for_completion(&sbi->s_kobj_unregister);
+ lock_super(sb);
+ lock_kernel();
kfree(sbi->s_blockgroup_lock);
kfree(sbi);
return;
@@ -1464,6 +1477,11 @@
return 0;
if (option < 0 || option > (1 << 30))
return 0;
+ if (option & (option - 1)) {
+ printk(KERN_ERR "EXT4-fs: inode_readahead_blks"
+ " must be a power of 2\n");
+ return 0;
+ }
sbi->s_inode_readahead_blks = option;
break;
case Opt_journal_ioprio:
@@ -1992,6 +2010,181 @@
return 0;
}
+/* sysfs supprt */
+
+struct ext4_attr {
+ struct attribute attr;
+ ssize_t (*show)(struct ext4_attr *, struct ext4_sb_info *, char *);
+ ssize_t (*store)(struct ext4_attr *, struct ext4_sb_info *,
+ const char *, size_t);
+ int offset;
+};
+
+static int parse_strtoul(const char *buf,
+ unsigned long max, unsigned long *value)
+{
+ char *endp;
+
+ while (*buf && isspace(*buf))
+ buf++;
+ *value = simple_strtoul(buf, &endp, 0);
+ while (*endp && isspace(*endp))
+ endp++;
+ if (*endp || *value > max)
+ return -EINVAL;
+
+ return 0;
+}
+
+static ssize_t delayed_allocation_blocks_show(struct ext4_attr *a,
+ struct ext4_sb_info *sbi,
+ char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "%llu\n",
+ (s64) percpu_counter_sum(&sbi->s_dirtyblocks_counter));
+}
+
+static ssize_t session_write_kbytes_show(struct ext4_attr *a,
+ struct ext4_sb_info *sbi, char *buf)
+{
+ struct super_block *sb = sbi->s_buddy_cache->i_sb;
+
+ return snprintf(buf, PAGE_SIZE, "%lu\n",
+ (part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
+ sbi->s_sectors_written_start) >> 1);
+}
+
+static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
+ struct ext4_sb_info *sbi, char *buf)
+{
+ struct super_block *sb = sbi->s_buddy_cache->i_sb;
+
+ return snprintf(buf, PAGE_SIZE, "%llu\n",
+ sbi->s_kbytes_written +
+ ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
+ EXT4_SB(sb)->s_sectors_written_start) >> 1));
+}
+
+static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
+ struct ext4_sb_info *sbi,
+ const char *buf, size_t count)
+{
+ unsigned long t;
+
+ if (parse_strtoul(buf, 0x40000000, &t))
+ return -EINVAL;
+
+ /* inode_readahead_blks must be a power of 2 */
+ if (t & (t-1))
+ return -EINVAL;
+
+ sbi->s_inode_readahead_blks = t;
+ return count;
+}
+
+static ssize_t sbi_ui_show(struct ext4_attr *a,
+ struct ext4_sb_info *sbi, char *buf)
+{
+ unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
+
+ return snprintf(buf, PAGE_SIZE, "%u\n", *ui);
+}
+
+static ssize_t sbi_ui_store(struct ext4_attr *a,
+ struct ext4_sb_info *sbi,
+ const char *buf, size_t count)
+{
+ unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
+ unsigned long t;
+
+ if (parse_strtoul(buf, 0xffffffff, &t))
+ return -EINVAL;
+ *ui = t;
+ return count;
+}
+
+#define EXT4_ATTR_OFFSET(_name,_mode,_show,_store,_elname) \
+static struct ext4_attr ext4_attr_##_name = { \
+ .attr = {.name = __stringify(_name), .mode = _mode }, \
+ .show = _show, \
+ .store = _store, \
+ .offset = offsetof(struct ext4_sb_info, _elname), \
+}
+#define EXT4_ATTR(name, mode, show, store) \
+static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
+
+#define EXT4_RO_ATTR(name) EXT4_ATTR(name, 0444, name##_show, NULL)
+#define EXT4_RW_ATTR(name) EXT4_ATTR(name, 0644, name##_show, name##_store)
+#define EXT4_RW_ATTR_SBI_UI(name, elname) \
+ EXT4_ATTR_OFFSET(name, 0644, sbi_ui_show, sbi_ui_store, elname)
+#define ATTR_LIST(name) &ext4_attr_##name.attr
+
+EXT4_RO_ATTR(delayed_allocation_blocks);
+EXT4_RO_ATTR(session_write_kbytes);
+EXT4_RO_ATTR(lifetime_write_kbytes);
+EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
+ inode_readahead_blks_store, s_inode_readahead_blks);
+EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
+EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
+EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
+EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
+EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
+EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
+
+static struct attribute *ext4_attrs[] = {
+ ATTR_LIST(delayed_allocation_blocks),
+ ATTR_LIST(session_write_kbytes),
+ ATTR_LIST(lifetime_write_kbytes),
+ ATTR_LIST(inode_readahead_blks),
+ ATTR_LIST(mb_stats),
+ ATTR_LIST(mb_max_to_scan),
+ ATTR_LIST(mb_min_to_scan),
+ ATTR_LIST(mb_order2_req),
+ ATTR_LIST(mb_stream_req),
+ ATTR_LIST(mb_group_prealloc),
+ NULL,
+};
+
+static ssize_t ext4_attr_show(struct kobject *kobj,
+ struct attribute *attr, char *buf)
+{
+ struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
+ s_kobj);
+ struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
+
+ return a->show ? a->show(a, sbi, buf) : 0;
+}
+
+static ssize_t ext4_attr_store(struct kobject *kobj,
+ struct attribute *attr,
+ const char *buf, size_t len)
+{
+ struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
+ s_kobj);
+ struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
+
+ return a->store ? a->store(a, sbi, buf, len) : 0;
+}
+
+static void ext4_sb_release(struct kobject *kobj)
+{
+ struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
+ s_kobj);
+ complete(&sbi->s_kobj_unregister);
+}
+
+
+static struct sysfs_ops ext4_attr_ops = {
+ .show = ext4_attr_show,
+ .store = ext4_attr_store,
+};
+
+static struct kobj_type ext4_ktype = {
+ .default_attrs = ext4_attrs,
+ .sysfs_ops = &ext4_attr_ops,
+ .release = ext4_sb_release,
+};
+
static int ext4_fill_super(struct super_block *sb, void *data, int silent)
__releases(kernel_lock)
__acquires(kernel_lock)
@@ -2575,6 +2768,16 @@
goto failed_mount4;
}
+ sbi->s_kobj.kset = ext4_kset;
+ init_completion(&sbi->s_kobj_unregister);
+ err = kobject_init_and_add(&sbi->s_kobj, &ext4_ktype, NULL,
+ "%s", sb->s_id);
+ if (err) {
+ ext4_mb_release(sb);
+ ext4_ext_release(sb);
+ goto failed_mount4;
+ };
+
/*
* akpm: core read_super() calls in here with the superblock locked.
* That deadlocks, because orphan cleanup needs to lock the superblock
@@ -3734,6 +3937,9 @@
{
int err;
+ ext4_kset = kset_create_and_add("ext4", NULL, fs_kobj);
+ if (!ext4_kset)
+ return -ENOMEM;
ext4_proc_root = proc_mkdir("fs/ext4", NULL);
err = init_ext4_mballoc();
if (err)
@@ -3775,6 +3981,7 @@
exit_ext4_xattr();
exit_ext4_mballoc();
remove_proc_entry("fs/ext4", NULL);
+ kset_unregister(ext4_kset);
}
MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");