ext4: Add sysfs support
authorTheodore Ts'o <tytso@mit.edu>
Tue, 31 Mar 2009 13:10:09 +0000 (09:10 -0400)
committerTheodore Ts'o <tytso@mit.edu>
Tue, 31 Mar 2009 13:10:09 +0000 (09:10 -0400)
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>
Documentation/ABI/testing/sysfs-fs-ext4 [new file with mode: 0644]
fs/ext4/ext4_sb.h
fs/ext4/super.c

diff --git a/Documentation/ABI/testing/sysfs-fs-ext4 b/Documentation/ABI/testing/sysfs-fs-ext4
new file mode 100644 (file)
index 0000000..4e79074
--- /dev/null
@@ -0,0 +1,81 @@
+What:          /sys/fs/ext4/<disk>/mb_stats
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+                Controls whether the multiblock allocator should
+                collect statistics, which are shown during the unmount.
+                1 means to collect statistics, 0 means not to collect
+                statistics
+
+What:          /sys/fs/ext4/<disk>/mb_group_prealloc
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               The multiblock allocator will round up allocation
+               requests to a multiple of this tuning parameter if the
+               stripe size is not set in the ext4 superblock
+
+What:          /sys/fs/ext4/<disk>/mb_max_to_scan
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               The maximum number of extents the multiblock allocator
+               will search to find the best extent
+
+What:          /sys/fs/ext4/<disk>/mb_min_to_scan
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               The minimum number of extents the multiblock allocator
+               will search to find the best extent
+
+What:          /sys/fs/ext4/<disk>/mb_order2_req
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               Tuning parameter which controls the minimum size for 
+               requests (as a power of 2) where the buddy cache is
+               used
+
+What:          /sys/fs/ext4/<disk>/mb_stream_req
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               Files which have fewer blocks than this tunable
+               parameter will have their blocks allocated out of a
+               block group specific preallocation pool, so that small
+               files are packed closely together.  Each large file
+                will have its blocks allocated out of its own unique
+                preallocation pool.
+
+What:          /sys/fs/ext4/<disk>/inode_readahead
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               Tuning parameter which controls the maximum number of
+               inode table blocks that ext4's inode table readahead
+               algorithm will pre-read into the buffer cache
+
+What:          /sys/fs/ext4/<disk>/delayed_allocation_blocks
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               This file is read-only and shows the number of blocks
+               that are dirty in the page cache, but which do not
+               have their location in the filesystem allocated yet.
+
+What:          /sys/fs/ext4/<disk>/lifetime_write_kbytes
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               This file is read-only and shows the number of kilobytes
+               of data that have been written to this filesystem since it was
+               created.
+
+What:          /sys/fs/ext4/<disk>/session_write_kbytes
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               This file is read-only and shows the number of
+               kilobytes of data that have been written to this
+               filesystem since it was mounted.
index 50ab1169c378bbcc2e8e5b746fc2a6064a51e4ce..57b71fefbccf753fb05e2436eea4da2da7663b3a 100644 (file)
@@ -64,6 +64,8 @@ struct ext4_sb_info {
        struct percpu_counter s_dirtyblocks_counter;
        struct blockgroup_lock *s_blockgroup_lock;
        struct proc_dir_entry *s_proc;
+       struct kobject s_kobj;
+       struct completion s_kobj_unregister;
 
        /* Journaling */
        struct inode *s_journal_inode;
index 30fc27cdf8fc90673414e0e11bc946128a6b6faa..2883d4318c228d9d4cc87a7132ec30b1eeeec394 100644 (file)
@@ -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 @@ static void ext4_put_super(struct super_block *sb)
                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 @@ static void ext4_put_super(struct super_block *sb)
                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 @@ set_qf_format:
                                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 @@ static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
        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 @@ no_journal:
                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 @@ static int __init init_ext4_fs(void)
 {
        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 @@ static void __exit exit_ext4_fs(void)
        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");