Add basic sysfs support so that information about the mounted
filesystem can be accessed via /sys/fs/fat/<dev>/*.
Signed-off-by: Denis Karpov <ext-denis.2.karpov@xxxxxxxxx>
---
fs/fat/fat.h | 6 +++
fs/fat/inode.c | 138 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 144 insertions(+), 0 deletions(-)
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index ea440d6..d1cec33 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -72,6 +72,9 @@ struct msdos_sb_info {
int dir_per_block; /* dir entries per block */
int dir_per_block_bits; /* log2(dir_per_block) */
+ struct kobject s_kobj; /* kobject corresponfing to fs volume */
+ struct completion s_kobj_unregister;
+
int fatent_shift;
struct fatent_operations *fatent_ops;
@@ -309,6 +312,9 @@ extern int fat_fill_super(struct super_block *sb, void *data, int silent,
extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
struct inode *i2);
+extern int fat_sbi_attr_set_notify(struct msdos_sb_info *sbi,
+ unsigned long offset, unsigned long val);
+
/* fat/misc.c */
extern void fat_fs_panic(struct super_block *s, const char *fmt, ...)
__attribute__ ((format (printf, 2, 3))) __cold;
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 296785a..82708fc 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -27,6 +27,7 @@
#include <linux/writeback.h>
#include <linux/log2.h>
#include <linux/hash.h>
+#include <linux/ctype.h>
#include <asm/unaligned.h>
#include "fat.h"
@@ -35,6 +36,8 @@
#define CONFIG_FAT_DEFAULT_IOCHARSET ""
#endif
+static struct kset *fat_kset;
+
static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
@@ -451,6 +454,7 @@ static void fat_put_super(struct super_block *sb)
{
struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ kobject_del(&sbi->s_kobj);
if (sbi->nls_disk) {
unload_nls(sbi->nls_disk);
sbi->nls_disk = NULL;
@@ -466,6 +470,10 @@ static void fat_put_super(struct super_block *sb)
}
sb->s_fs_info = NULL;
+
+ kobject_put(&sbi->s_kobj);
+ wait_for_completion(&sbi->s_kobj_unregister);
+
kfree(sbi);
}
@@ -1168,6 +1176,126 @@ static int fat_read_root(struct inode *inode)
return 0;
}
+/* sysfs support */
+
+struct fat_attr {
+ struct attribute attr;
+ ssize_t (*show)(struct fat_attr *, struct msdos_sb_info *, char *);
+ ssize_t (*store)(struct fat_attr *, struct msdos_sb_info *,
+ const char *, size_t);
+ unsigned short offset;
+};
+
+static ssize_t fat_sbi_attr_show(struct fat_attr *a, struct msdos_sb_info *sbi,
+ char *buf)
+{
+ unsigned long attr_val = *(unsigned long *)(((char *) sbi) + a->offset);
+ return snprintf(buf, PAGE_SIZE, "%lu\n", attr_val);
+}
+
+static ssize_t fat_sbi_attr_store(struct fat_attr *a,
+ struct msdos_sb_info *sbi,
+ const char *buf, size_t count)
+{
+ unsigned long *attr_val = (unsigned long *)(((char *) sbi) + a->offset);
+
+ if (strict_strtoul(buf, 10, attr_val))
+ return -EINVAL;
+
+ return count;
+}
+
+#define FAT_SBI_ATTR(_name, _mode, _show, _store) \
+static struct fat_attr fat_attr_##_name = { \
+ .attr = {.name = __stringify(_name), .mode = _mode }, \
+ .show = _show, \
+ .store = _store, \
+ .offset = offsetof(struct msdos_sb_info, _name), \
+}
+#define FAT_SBI_RO_ATTR(name) FAT_SBI_ATTR(name, 0444, \
+ fat_sbi_attr_show, NULL)
+#define FAT_SBI_RW_ATTR(name) FAT_SBI_ATTR(name, 0644 \
+ fat_sbi_attr_show, fat_sbi_attr_store)
+
+#define ATTR_LIST(name) (&fat_attr_ ##name.attr)
+
+static struct attribute *fat_attrs[] = {
+ NULL
+};
+
+static struct attribute *find_attr_by_offset(struct kobject *kobj,
+ unsigned long offset)
+{
+ struct fat_attr **a = (struct fat_attr **)kobj->ktype->default_attrs;
+
+ for (; *a && (*a)->offset != offset; a++)
+ ;
+
+ return (struct attribute *)*a;
+}
+
+int fat_sbi_attr_set_notify(struct msdos_sb_info *sbi,
+ unsigned long offset,
+ unsigned long val)
+{
+ struct fat_attr *a =
+ (struct fat_attr *) find_attr_by_offset(&sbi->s_kobj, offset);
+ unsigned long *attr_val;
+
+ if (!a)
+ return -EINVAL;
+
+ attr_val = (unsigned long *) (((char *) sbi) + a->offset);
+ if (*attr_val == val)
+ return 0;
+
+ *attr_val = val;
+
+ sysfs_notify(&sbi->s_kobj, NULL, a->attr.name);
+
+ return 0;
+}
+EXPORT_SYMBOL(fat_sbi_attr_set_notify);
+
+static ssize_t fat_attr_show(struct kobject *kobj, struct attribute *attr,
+ char *buf)
+{
+ struct msdos_sb_info *sbi = container_of(kobj, struct msdos_sb_info,
+ s_kobj);
+ struct fat_attr *a = container_of(attr, struct fat_attr, attr);
+
+ return a->show ? a->show(a, sbi, buf) : 0;
+}
+
+static ssize_t fat_attr_store(struct kobject *kobj,
+ struct attribute *attr,
+ const char *buf, size_t len)
+{
+ struct msdos_sb_info *sbi = container_of(kobj, struct msdos_sb_info,
+ s_kobj);
+ struct fat_attr *a = container_of(attr, struct fat_attr, attr);
+
+ return a->store ? a->store(a, sbi, buf, len) : 0;
+}
+
+static void fat_sb_release(struct kobject *kobj)
+{
+ struct msdos_sb_info *sbi = container_of(kobj, struct msdos_sb_info,
+ s_kobj);
+ complete(&sbi->s_kobj_unregister);
+}
+
+static struct sysfs_ops fat_attr_ops = {
+ .show = fat_attr_show,
+ .store = fat_attr_store,
+};
+
+static struct kobj_type fat_ktype = {
+ .default_attrs = fat_attrs,
+ .sysfs_ops = &fat_attr_ops,
+ .release = fat_sb_release,
+};
+
/*
* Read the super block of an MS-DOS FS.
*/
@@ -1430,6 +1558,11 @@ int fat_fill_super(struct super_block *sb, void *data, int silent,
goto out_fail;
}
+ sbi->s_kobj.kset = fat_kset;
+ init_completion(&sbi->s_kobj_unregister);
+ error = kobject_init_and_add(&sbi->s_kobj, &fat_ktype, NULL,
+ "%s", sb->s_id);
+
return 0;
out_invalid:
@@ -1508,6 +1641,10 @@ static int __init init_fat_fs(void)
{
int err;
+ fat_kset = kset_create_and_add("fat", NULL, fs_kobj);
+ if (!fat_kset)
+ return -ENOMEM;
+
err = fat_cache_init();
if (err)
return err;
@@ -1527,6 +1664,7 @@ static void __exit exit_fat_fs(void)
{
fat_cache_destroy();
fat_destroy_inodecache();
+ kset_unregister(fat_kset);
}
module_init(init_fat_fs)
--
1.6.3.1
--
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