[Patch 13/18] fs/logfs/super.c

Jörn Engel
2007-08-08T16:25:39Z

--- /dev/null 2007-08-05 21:14:35.622844160 +0200
+++ linux-2.6.21logfs/fs/logfs/super.c 2007-08-08 02:57:37.000000000 +0200
@@ -0,0 +1,569 @@
+/*
+ * fs/logfs/super.c
+ *
+ * As should be obvious for Linux kernel code, license is GPLv2
+ *
+ * Copyright (c) 2005-2007 Joern Engel <joern@logfs.org>
+ *
+ * Generally contains mount/umount code and also serves and a dump area for
+ * any functions that don't fit elsewhere and neither justify a file of their
+ * own.
+ */
+#include "logfs.h"
+#include <linux/bio.h>
+#include <linux/mtd/mtd.h>
+#include <linux/statfs.h>
+#include <linux/buffer_head.h>
+
+static int mtd_read(struct super_block *sb, loff_t ofs, size_t len, void *buf)
+{
+ struct mtd_info *mtd = logfs_super(sb)->s_mtd;
+ size_t retlen;
+ int ret;
+
+ ret = mtd->read(mtd, ofs, len, &retlen, buf);
+ BUG_ON(ret == -EINVAL);
+ if (ret)
+ return ret;
+
+ /* Not sure if we should loop instead. */
+ if (retlen != len)
+ return -EIO;
+
+ return 0;
+}
+
+static int mtd_write(struct super_block *sb, loff_t ofs, size_t len, void *buf)
+{
+ struct logfs_super *super = logfs_super(sb);
+ struct mtd_info *mtd = super->s_mtd;
+ size_t retlen;
+ loff_t page_start, page_end;
+ int ret;
+
+ if (super->s_flags & LOGFS_SB_FLAG_RO)
+ return -EROFS;
+
+ BUG_ON((ofs >= mtd->size) || (len > mtd->size - ofs));
+ BUG_ON(ofs != (ofs >> super->s_writeshift) << super->s_writeshift);
+ BUG_ON(len > PAGE_CACHE_SIZE);
+ page_start = ofs & PAGE_CACHE_MASK;
+ page_end = PAGE_CACHE_ALIGN(ofs + len) - 1;
+ ret = mtd->write(mtd, ofs, len, &retlen, buf);
+ if (ret || (retlen != len))
+ return -EIO;
+
+ return 0;
+}
+
+/*
+ * For as long as I can remember (since about 2001) mtd->erase has been an
+ * asynchronous interface lacking the first driver to actually use the
+ * asynchronous properties. So just to prevent the first implementor of such
+ * a thing from breaking logfs in 2350, we do the usual pointless dance to
+ * declare a completion variable and wait for completion before returning
+ * from mtd_erase(). What an excercise in futility!
+ */
+static void logfs_erase_callback(struct erase_info *ei)
+{
+ complete((struct completion*)ei->priv);
+}
+
+static int mtd_erase(struct super_block *sb, loff_t ofs, size_t len)
+{
+ struct mtd_info *mtd = logfs_super(sb)->s_mtd;
+ struct erase_info ei;
+ DECLARE_COMPLETION_ONSTACK(complete);
+ int ret;
+
+ BUG_ON(len % mtd->erasesize);
+
+ if (logfs_super(sb)->s_flags & LOGFS_SB_FLAG_RO)
+ return -EROFS;
+
+ memset(&ei, 0, sizeof(ei));
+ ei.mtd = mtd;
+ ei.addr = ofs;
+ ei.len = len;
+ ei.callback = logfs_erase_callback;
+ ei.priv = (long)&complete;
+ ret = mtd->erase(mtd, &ei);
+ if (ret)
+ return -EIO;
+
+ wait_for_completion(&complete);
+ if (ei.state != MTD_ERASE_DONE)
+ return -EIO;
+ return 0;
+}
+
+static void mtd_sync(struct super_block *sb)
+{
+ struct mtd_info *mtd = logfs_super(sb)->s_mtd;
+
+ if (mtd->sync)
+ mtd->sync(mtd);
+}
+
+static const struct logfs_device_ops mtd_devops = {
+ .read = mtd_read,
+ .write = mtd_write,
+ .erase = mtd_erase,
+ .sync = mtd_sync,
+};
+
+static int bdev_read(struct super_block *sb, loff_t from, size_t len, void *buf)
+{
+ struct block_device *bdev = logfs_super(sb)->s_bdev;
+ struct address_space *mapping = bdev->bd_inode->i_mapping;
+ struct page *page;
+ long index = from >> PAGE_SHIFT;
+ long offset = from & (PAGE_SIZE-1);
+ long copylen;
+
+ while (len) {
+ copylen = min((ulong)len, PAGE_SIZE - offset);
+
+ page = read_cache_page(mapping, index,
+ (filler_t*)mapping->a_ops->readpage, NULL);
+ if (!page)
+ return -ENOMEM;
+ if (IS_ERR(page))
+ return PTR_ERR(page);
+
+ memcpy(buf, page_address(page) + offset, copylen);
+ page_cache_release(page);
+
+ buf += copylen;
+ len -= copylen;
+ offset = 0;
+ index++;
+ }
+ return 0;
+}
+
+static int bdev_write(struct super_block *sb, loff_t to, size_t len, void *buf)
+{
+ struct block_device *bdev = logfs_super(sb)->s_bdev;
+ struct address_space *mapping = bdev->bd_inode->i_mapping;
+ struct page *page;
+ long index = to >> PAGE_SHIFT;
+ long offset = to & (PAGE_SIZE-1);
+ long copylen;
+
+ if (logfs_super(sb)->s_flags & LOGFS_SB_FLAG_RO)
+ return -EROFS;
+
+ while (len) {
+ copylen = min((ulong)len, PAGE_SIZE - offset);
+
+ page = read_cache_page(mapping, index,
+ (filler_t*)mapping->a_ops->readpage, NULL);
+ if (!page)
+ return -ENOMEM;
+ if (IS_ERR(page))
+ return PTR_ERR(page);
+ lock_page(page);
+ memcpy(page_address(page) + offset, buf, copylen);
+ set_page_dirty(page);
+ unlock_page(page);
+ page_cache_release(page);
+
+ buf += copylen;
+ len -= copylen;
+ offset = 0;
+ index++;
+ }
+ return 0;
+}
+
+static int bdev_erase(struct super_block *sb, loff_t to, size_t len)
+{
+ struct block_device *bdev = logfs_super(sb)->s_bdev;
+ struct address_space *mapping = bdev->bd_inode->i_mapping;
+ struct page *page;
+ long index = to >> PAGE_SHIFT;
+ long offset = to & (PAGE_SIZE-1);
+ long copylen;
+
+ if (logfs_super(sb)->s_flags & LOGFS_SB_FLAG_RO)
+ return -EROFS;
+
+ while (len) {
+ copylen = min((ulong)len, PAGE_SIZE - offset);
+
+ page = read_cache_page(mapping, index,
+ (filler_t*)mapping->a_ops->readpage, NULL);
+ if (!page)
+ return -ENOMEM;
+ if (IS_ERR(page))
+ return PTR_ERR(page);
+ lock_page(page);
+ memset(page_address(page) + offset, 0xFF, copylen);
+ set_page_dirty(page);
+ unlock_page(page);
+ page_cache_release(page);
+
+ len -= copylen;
+ offset = 0;
+ index++;
+ }
+ return 0;
+}
+
+static void bdev_sync(struct super_block *sb)
+{
+ sync_blockdev(logfs_super(sb)->s_bdev);
+}
+
+static const struct logfs_device_ops bd_devops = {
+ .read = bdev_read,
+ .write = bdev_write,
+ .erase = bdev_erase,
+ .sync = bdev_sync,
+};
+
+static void dump_write(struct super_block *sb, int blockno, void *buf)
+{
+ struct logfs_super *super = logfs_super(sb);
+
+ if (blockno << sb->s_blocksize_bits >= super->s_segsize)
+ return;
+ super->s_devops->write(sb, blockno << sb->s_blocksize_bits,
+ sb->s_blocksize, buf);
+}
+
+/*
+ * logfs_crash_dump - dump debug information to device
+ *
+ * The LogFS superblock only occupies part of a segment. This function will
+ * write as much debug information as it can gather into the spare space.
+ */
+void logfs_crash_dump(struct super_block *sb)
+{
+ struct logfs_super *super = logfs_super(sb);
+ int i, blockno = 2, bs = sb->s_blocksize;
+ void *scratch = super->s_wblock[0];
+ void *stack = (void *) ((ulong)current & ~0x1fffUL);
+
+ /* all wbufs */
+ for (i=0; i<LOGFS_NO_AREAS; i++) {
+ void *wbuf = super->s_area[i]->a_wbuf;
+ u64 ofs = sb->s_blocksize + i*super->s_writesize;
+ super->s_devops->write(sb, ofs, super->s_writesize, wbuf);
+ }
+ /* both superblocks */
+ memset(scratch, 0, bs);
+ memcpy(scratch, super, sizeof(*super));
+ memcpy(scratch + sizeof(*super) + 32, sb, sizeof(*sb));
+ dump_write(sb, blockno++, scratch);
+ /* process stack */
+ dump_write(sb, blockno++, stack);
+ dump_write(sb, blockno++, stack + 0x1000);
+ /* wblocks are interesting whenever readwrite.c causes problems */
+ for (i=0; i<LOGFS_MAX_LEVELS; i++)
+ dump_write(sb, blockno++, super->s_wblock[i]);
+}
+
+/*
+ * TODO: move to lib/string.c
+ */
+/**
+ * memchr_inv - Find a character in an area of memory.
+ * @s: The memory area
+ * @c: The byte to search for
+ * @n: The size of the area.
+ *
+ * returns the address of the first character other than @c, or %NULL
+ * if the whole buffer contains just @c.
+ */
+void *memchr_inv(const void *s, int c, size_t n)
+{
+ const unsigned char *p = s;
+ while (n-- != 0) {
+ if ((unsigned char)c != *p++) {
+ return (void *)(p - 1);
+ }
+ }
+ return NULL;
+}
+
+/*
+ * FIXME: There should be a reserve for root, similar to ext2.
+ */
+int logfs_statfs(struct dentry *dentry, struct kstatfs *stats)
+{
+ struct super_block *sb = dentry->d_sb;
+ struct logfs_super *super = logfs_super(sb);
+
+ stats->f_type = LOGFS_MAGIC_U32;
+ stats->f_bsize = sb->s_blocksize;
+ stats->f_blocks = super->s_size >> LOGFS_BLOCK_BITS >> 3;
+ stats->f_bfree = super->s_free_bytes >> sb->s_blocksize_bits;
+ stats->f_bavail = super->s_free_bytes >> sb->s_blocksize_bits;
+ stats->f_files = 0;
+ stats->f_ffree = 0;
+ stats->f_namelen= LOGFS_MAX_NAMELEN;
+ return 0;
+}
+
+static int logfs_sb_set(struct super_block *sb, void *super)
+{
+ sb->s_fs_info = super;
+ return 0;
+}
+
+static int logfs_get_sb_final(struct super_block *sb, struct vfsmount *mnt)
+{
+ struct inode *rootdir;
+ int err;
+
+ /* root dir */
+ rootdir = iget(sb, LOGFS_INO_ROOT);
+ if (!rootdir)
+ goto fail;
+
+ sb->s_root = d_alloc_root(rootdir);
+ if (!sb->s_root)
+ goto fail;
+
+ err = logfs_fsck(sb);
+ if (err) {
+ printk(KERN_ERR"LOGFS: fsck failed, refusing to mount\n");
+ goto fail;
+ }
+ return simple_set_mnt(mnt, sb);
+
+fail:
+ iput(logfs_super(sb)->s_master_inode);
+ return -EIO;
+}
+
+static int logfs_read_sb(struct super_block *sb)
+{
+ struct logfs_super *super = logfs_super(sb);
+ struct logfs_disk_super ds;
+ int i, ret;
+
+ ret = super->s_devops->read(sb, 0, sizeof(ds), &ds);
+ if (ret)
+ return ret;
+
+ ret = -EIO;
+ if (be64_to_cpu(ds.ds_magic) != LOGFS_MAGIC)
+ goto out0;
+
+ super->s_size = be64_to_cpu(ds.ds_filesystem_size);
+ super->s_root_reserve = be64_to_cpu(ds.ds_root_reserve);
+ super->s_segsize = 1 << ds.ds_segment_shift;
+ super->s_segshift = ds.ds_segment_shift;
+ sb->s_blocksize = 1 << ds.ds_block_shift;
+ sb->s_blocksize_bits = ds.ds_block_shift;
+ super->s_writesize = 1 << ds.ds_write_shift;
+ super->s_writeshift = ds.ds_write_shift;
+ super->s_no_segs = super->s_size >> super->s_segshift;
+ super->s_no_blocks = super->s_segsize >> sb->s_blocksize_bits;
+
+ journal_for_each(i)
+ super->s_journal_seg[i] = be64_to_cpu(ds.ds_journal_seg[i]);
+
+ super->s_ifile_levels = ds.ds_ifile_levels;
+ super->s_iblock_levels = ds.ds_iblock_levels;
+ super->s_data_levels = ds.ds_data_levels;
+ super->s_total_levels = super->s_ifile_levels + super->s_iblock_levels
+ + super->s_data_levels;
+ super->s_gc_reserve = super->s_total_levels * (2*super->s_no_blocks -1);
+ super->s_gc_reserve <<= sb->s_blocksize_bits;
+
+ mutex_init(&super->s_dirop_mutex);
+ spin_lock_init(&super->s_ino_lock);
+ INIT_LIST_HEAD(&super->s_freeing_list);
+
+ ret = logfs_init_rw(super);
+ if (ret)
+ goto out0;
+
+ ret = logfs_init_areas(sb);
+ if (ret)
+ goto out1;
+
+ ret = logfs_init_journal(sb);
+ if (ret)
+ goto out2;
+
+ ret = logfs_init_gc(super);
+ if (ret)
+ goto out3;
+
+ /* Do one GC pass before any data gets dirtied */
+ logfs_gc_pass(sb);
+
+ /* after all initializations are done, replay the journal
+ * for rw-mounts, if necessary */
+ ret = logfs_replay_journal(sb);
+ if (ret)
+ goto out4;
+ return 0;
+
+out4:
+ logfs_cleanup_gc(super);
+out3:
+ logfs_cleanup_journal(sb);
+out2:
+ logfs_cleanup_areas(super);
+out1:
+ logfs_cleanup_rw(super);
+out0:
+ return ret;
+}
+
+static void logfs_kill_sb(struct super_block *sb)
+{
+ struct logfs_super *super = logfs_super(sb);
+
+ generic_shutdown_super(sb);
+ logfs_cleanup_gc(super);
+ logfs_cleanup_journal(sb);
+ logfs_cleanup_areas(super);
+ logfs_cleanup_rw(super);
+ if (super->s_mtd)
+ put_mtd_device(super->s_mtd);
+ if (super->s_bdev)
+ close_bdev_excl(super->s_bdev);
+ kfree(super);
+}
+
+static void init_logfs_super(struct logfs_super *super)
+{
+ INIT_LIST_HEAD(&super->s_free_list);
+ INIT_LIST_HEAD(&super->s_low_list);
+}
+
+static int logfs_get_sb_device(struct file_system_type *type, int flags,
+ struct mtd_info *mtd, struct block_device *bdev,
+ const struct logfs_device_ops *devops, struct vfsmount *mnt)
+{
+ struct logfs_super *super = NULL;
+ struct super_block *sb;
+ int err = -ENOMEM;
+
+ super = kzalloc(sizeof*super, GFP_KERNEL);
+ if (!super)
+ goto err0;
+
+ init_logfs_super(super);
+
+ err = -EINVAL;
+ sb = sget(type, NULL, logfs_sb_set, super);
+ if (IS_ERR(sb))
+ goto err0;
+
+ super->s_mtd = mtd;
+ super->s_bdev = bdev;
+ super->s_devops = devops;
+ sb->s_maxbytes = LOGFS_I3_SIZE;
+ sb->s_op = &logfs_super_operations;
+ sb->s_flags = flags | MS_NOATIME;
+
+ err = logfs_read_sb(sb);
+ if (err)
+ goto err1;
+
+ sb->s_flags |= MS_ACTIVE;
+ err = logfs_get_sb_final(sb, mnt);
+ if (err)
+ goto err1;
+ return 0;
+
+err1:
+ up_write(&sb->s_umount);
+ deactivate_super(sb);
+ return err;
+err0:
+ kfree(super);
+ if (mtd)
+ put_mtd_device(mtd);
+ if (bdev)
+ close_bdev_excl(bdev);
+ return err;
+}
+
+static int logfs_get_sb_bdev(struct file_system_type *type, int flags,
+ const char *devname, void *data, struct vfsmount *mnt)
+{
+ struct block_device *bdev;
+
+ bdev = open_bdev_excl(devname, O_RDWR, NULL);
+ if (IS_ERR(bdev))
+ return PTR_ERR(bdev);
+
+ if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
+ close_bdev_excl(bdev);
+ return -EINVAL; /* FIXME: fall back to mtd */
+ }
+
+ return logfs_get_sb_device(type, flags, NULL, bdev, &bd_devops, mnt);
+}
+
+static int logfs_get_sb(struct file_system_type *type, int flags,
+ const char *devname, void *data, struct vfsmount *mnt)
+{
+ ulong mtdnr;
+ struct mtd_info *mtd;
+
+ if (!devname)
+ return logfs_get_sb_bdev(type, flags, devname, data, mnt);
+ if (strncmp(devname, "mtd", 3))
+ return logfs_get_sb_bdev(type, flags, devname, data, mnt);
+
+ {
+ char *garbage;
+ mtdnr = simple_strtoul(devname+3, &garbage, 0);
+ if (*garbage)
+ return -EINVAL;
+ }
+
+ mtd = get_mtd_device(NULL, mtdnr);
+ if (!mtd)
+ return -EINVAL;
+
+ return logfs_get_sb_device(type, flags, mtd, NULL, &mtd_devops, mnt);
+}
+
+static struct file_system_type logfs_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "logfs",
+ .get_sb = logfs_get_sb,
+ .kill_sb = logfs_kill_sb,
+};
+
+static int __init logfs_init(void)
+{
+ int ret;
+
+ ret = logfs_compr_init();
+ if (ret)
+ return ret;
+
+ ret = logfs_init_inode_cache();
+ if (ret) {
+ logfs_compr_exit();
+ return ret;
+ }
+
+ return register_filesystem(&logfs_fs_type);
+}
+
+static void __exit logfs_exit(void)
+{
+ unregister_filesystem(&logfs_fs_type);
+ logfs_destroy_inode_cache();
+ logfs_compr_exit();
+}
+
+module_init(logfs_init);
+module_exit(logfs_exit);
+
+MODULE_LICENSE("GPLv2");
+MODULE_AUTHOR("Joern Engel <joern@logfs.org>");
+MODULE_DESCRIPTION("scalable flash filesystem");