Hello,
there are some users which have interest on such kind of file system like azfs. Please, have a look at this version of a diff file which introduces a first version of azfs to 2.6.26. This file system may be useful for example on IBM CellBlades where user can mount DDR2 memory of Axon controller as a disk and to be able to access it directly without any caching mechanism in between.
Subject: azfs: initial submit of azfs, a non-buffered filesystem
From: Maxim Shchetynin <maxim@xxxxxxxxxx>
Non-buffered filesystem for block devices with a gendisk and
with direct_access() method in gendisk->fops.
AZFS does not buffer outgoing traffic and is doing no read ahead.
It supports mount options (given with -o) bs=x,uid=x,gid=x.
If block-size (bs) is not specified AZFS uses block-size used
by block device. Though mmap() method is available only if
block-size equals to or is greater than the system page size.
Signed-off-by: Maxim Shchetynin <maxim@xxxxxxxxxx>
diff -Nuar linux-2.6.26-rc5/arch/powerpc/configs/cell_defconfig linux-2.6.26-rc5-azfs/arch/powerpc/configs/cell_defconfig
--- linux-2.6.26-rc5/arch/powerpc/configs/cell_defconfig 2008-06-05 05:10:44.000000000 +0200
+++ linux-2.6.26-rc5-azfs/arch/powerpc/configs/cell_defconfig 2008-06-06 11:53:34.000000000 +0200
@@ -240,6 +240,7 @@
# CPU Frequency drivers
#
CONFIG_AXON_RAM=m
+CONFIG_AZ_FS=m
# CONFIG_FSL_ULI1575 is not set
#
diff -Nuar linux-2.6.26-rc5/fs/Kconfig linux-2.6.26-rc5-azfs/fs/Kconfig
--- linux-2.6.26-rc5/fs/Kconfig 2008-06-05 05:10:44.000000000 +0200
+++ linux-2.6.26-rc5-azfs/fs/Kconfig 2008-06-06 16:55:11.616419992 +0200
@@ -360,6 +360,17 @@
If you are not using a security module that requires using
extended attributes for file security labels, say N.
+config AZ_FS
+ tristate "AZFS filesystem support"
+ help
+ Non-buffered filesystem for block devices with a gendisk and
+ with direct_access() method in gendisk->fops.
+ AZFS does not buffer outgoing traffic and is doing no read ahead.
+ It supports mount options (given with -o) bs=x,uid=x,gid=x.
+ If block-size (bs) is not specified AZFS uses block-size used
+ by block device. Though mmap() method is available only if
+ block-size equals to or is greater than system page size.
+
config JFS_FS
tristate "JFS filesystem support"
select NLS
diff -Nuar linux-2.6.26-rc5/fs/Makefile linux-2.6.26-rc5-azfs/fs/Makefile
--- linux-2.6.26-rc5/fs/Makefile 2008-06-05 05:10:44.000000000 +0200
+++ linux-2.6.26-rc5-azfs/fs/Makefile 2008-06-06 11:53:34.000000000 +0200
@@ -119,3 +119,4 @@
obj-$(CONFIG_DEBUG_FS) += debugfs/
obj-$(CONFIG_OCFS2_FS) += ocfs2/
obj-$(CONFIG_GFS2_FS) += gfs2/
+obj-$(CONFIG_AZ_FS) += azfs.o
diff -Nuar linux-2.6.26-rc5/fs/azfs.c linux-2.6.26-rc5-azfs/fs/azfs.c
--- linux-2.6.26-rc5/fs/azfs.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.26-rc5-azfs/fs/azfs.c 2008-06-06 17:46:23.587653053 +0200
@@ -0,0 +1,1179 @@
+/*
+ * (C) Copyright IBM Deutschland Entwicklung GmbH 2007
+ *
+ * Author: Maxim Shchetynin <maxim@xxxxxxxxxx>
+ *
+ * Non-buffered filesystem driver.
+ * It registers a filesystem which may be used for all kind of block devices
+ * which have a direct_access() method in block_device_operations.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/backing-dev.h>
+#include <linux/blkdev.h>
+#include <linux/cache.h>
+#include <linux/dcache.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/fs.h>
+#include <linux/genhd.h>
+#include <linux/kernel.h>
+#include <linux/limits.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/mm.h>
+#include <linux/mm_types.h>
+#include <linux/mutex.h>
+#include <linux/namei.h>
+#include <linux/pagemap.h>
+#include <linux/parser.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/stat.h>
+#include <linux/statfs.h>
+#include <linux/string.h>
+#include <linux/time.h>
+#include <linux/types.h>
+#include <linux/aio.h>
+#include <linux/uio.h>
+#include <asm/bug.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/string.h>
+
+#define AZFS_FILESYSTEM_NAME "azfs"
+#define AZFS_FILESYSTEM_FLAGS FS_REQUIRES_DEV
+
+#define AZFS_SUPERBLOCK_MAGIC 0xABBA1972
+#define AZFS_SUPERBLOCK_FLAGS MS_NOEXEC | \
+ MS_SYNCHRONOUS | \
+ MS_DIRSYNC | \
+ MS_ACTIVE
+
+#define AZFS_BDI_CAPABILITIES BDI_CAP_NO_ACCT_DIRTY | \
+ BDI_CAP_NO_WRITEBACK | \
+ BDI_CAP_MAP_COPY | \
+ BDI_CAP_MAP_DIRECT | \
+ BDI_CAP_VMFLAGS
+
+#define AZFS_CACHE_FLAGS SLAB_HWCACHE_ALIGN | \
+ SLAB_RECLAIM_ACCOUNT | \
+ SLAB_MEM_SPREAD
+
+enum azfs_direction {
+ AZFS_MMAP,
+ AZFS_READ,
+ AZFS_WRITE
+};
+
+struct azfs_super {
+ struct list_head list;
+ unsigned long media_size;
+ unsigned long block_size;
+ unsigned short block_shift;
+ unsigned long sector_size;
+ unsigned short sector_shift;
+ uid_t uid;
+ gid_t gid;
+ unsigned long ph_addr;
+ unsigned long io_addr;
+ struct block_device *blkdev;
+ struct dentry *root;
+ struct list_head block_list;
+ rwlock_t lock;
+};
+
+struct azfs_super_list {
+ struct list_head head;
+ spinlock_t lock;
+};
+
+struct azfs_block {
+ struct list_head list;
+ unsigned long id;
+ unsigned long count;
+};
+
+struct azfs_znode {
+ struct list_head block_list;
+ rwlock_t lock;
+ loff_t size;
+ struct inode vfs_inode;
+};
+
+static struct azfs_super_list super_list;
+static struct kmem_cache *azfs_znode_cache __read_mostly = NULL;
+static struct kmem_cache *azfs_block_cache __read_mostly = NULL;
+
+#define I2Z(inode) \
+ container_of(inode, struct azfs_znode, vfs_inode)
+
+#define for_each_block(block, block_list) \
+ list_for_each_entry(block, block_list, list)
+#define for_each_block_reverse(block, block_list) \
+ list_for_each_entry_reverse(block, block_list, list)
+#define for_each_block_safe(block, ding, block_list) \
+ list_for_each_entry_safe(block, ding, block_list, list)
+#define for_each_block_safe_reverse(block, ding, block_list) \
+ list_for_each_entry_safe_reverse(block, ding, block_list, list)
+
+/**
+ * azfs_block_init - create and initialise a new block in a list
+ * @block_list: destination list
+ * @id: block id
+ * @count: size of a block
+ */
+static inline struct azfs_block*
+azfs_block_init(struct list_head *block_list,
+ unsigned long id, unsigned long count)
+{
+ struct azfs_block *block;
+
+ block = kmem_cache_alloc(azfs_block_cache, GFP_KERNEL);
+ if (!block)
+ return NULL;
+
+ block->id = id;
+ block->count = count;
+
+ INIT_LIST_HEAD(&block->list);
+ list_add_tail(&block->list, block_list);
+
+ return block;
+}
+
+/**
+ * azfs_block_free - remove block from a list and free it back in cache
+ * @block: block to be removed
+ */
+static inline void
+azfs_block_free(struct azfs_block *block)
+{
+ list_del(&block->list);
+ kmem_cache_free(azfs_block_cache, block);
+}
+
+/**
+ * azfs_block_move - move block to another list
+ * @block: block to be moved
+ * @block_list: destination list
+ */
+static inline void
+azfs_block_move(struct azfs_block *block, struct list_head *block_list)
+{
+ list_move_tail(&block->list, block_list);
+}
+
+/**
+ * azfs_recherche - get real address of a part of a file
+ * @inode: inode
+ * @direction: data direction
+ * @from: offset for read/write operation
+ * @size: pointer to a value of the amount of data to be read/written
+ */
+static unsigned long
+azfs_recherche(struct inode *inode, enum azfs_direction direction,
+ unsigned long from, unsigned long *size)
+{
+ struct azfs_super *super;
+ struct azfs_znode *znode;
+ struct azfs_block *block;
+ unsigned long block_id, west, east;
+
+ super = inode->i_sb->s_fs_info;
+ znode = I2Z(inode);
+
+ if (from + *size > znode->size) {
+ i_size_write(inode, from + *size);
+ inode->i_op->truncate(inode);
+ }
+
+ read_lock(&znode->lock);
+
+ if (list_empty(&znode->block_list)) {
+ read_unlock(&znode->lock);
+ return 0;
+ }
+
+ block_id = from >> super->block_shift;
+
+ for_each_block(block, &znode->block_list) {
+ if (block->count > block_id)
+ break;
+ block_id -= block->count;
+ }
+
+ west = from % super->block_size;
+ east = ((block->count - block_id) << super->block_shift) - west;
+
+ if (*size > east)
+ *size = east;
+
+ block_id = ((block->id + block_id) << super->block_shift) + west;
+
+ read_unlock(&znode->lock);
+
+ block_id += direction == AZFS_MMAP ? super->ph_addr : super->io_addr;
+
+ return block_id;
+}
+
+static struct inode*
+azfs_new_inode(struct super_block *, struct inode *, int, dev_t);
+
+/**
+ * azfs_mknod - mknod() method for inode_operations
+ * @dir, @dentry, @mode, @dev: see inode_operations methods
+ */
+static int
+azfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
+{
+ struct inode *inode;
+
+ inode = azfs_new_inode(dir->i_sb, dir, mode, dev);
+ if (!inode)
+ return -ENOSPC;
+
+ if (S_ISREG(mode))
+ I2Z(inode)->size = 0;
+
+ dget(dentry);
+ d_instantiate(dentry, inode);
+
+ return 0;
+}
+
+/**
+ * azfs_create - create() method for inode_operations
+ * @dir, @dentry, @mode, @nd: see inode_operations methods
+ */
+static int
+azfs_create(struct inode *dir, struct dentry *dentry, int mode,
+ struct nameidata *nd)
+{
+ return azfs_mknod(dir, dentry, mode | S_IFREG, 0);
+}
+
+/**
+ * azfs_mkdir - mkdir() method for inode_operations
+ * @dir, @dentry, @mode: see inode_operations methods
+ */
+static int
+azfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+ int rc;
+
+ rc = azfs_mknod(dir, dentry, mode | S_IFDIR, 0);
+ if (rc == 0)
+ inc_nlink(dir);
+
+ return rc;
+}
+
+/**
+ * azfs_symlink - symlink() method for inode_operations
+ * @dir, @dentry, @name: see inode_operations methods
+ */
+static int
+azfs_symlink(struct inode *dir, struct dentry *dentry, const char *name)
+{
+ struct inode *inode;
+ int rc;
+
+ inode = azfs_new_inode(dir->i_sb, dir, S_IFLNK | S_IRWXUGO, 0);
+ if (!inode)
+ return -ENOSPC;
+
+ rc = page_symlink(inode, name, strlen(name) + 1);
+ if (rc) {
+ iput(inode);
+ return rc;
+ }
+
+ dget(dentry);
+ d_instantiate(dentry, inode);
+
+ return 0;
+}
+
+/**
+ * azfs_aio_read - aio_read() method for file_operations
+ * @iocb, @iov, @nr_segs, @pos: see file_operations methods
+ */
+static ssize_t
+azfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
+{
+ struct inode *inode;
+ void *ziel;
+ unsigned long pin;
+ unsigned long size, todo, step;
+ ssize_t rc;
+
+ inode = iocb->ki_filp->f_mapping->host;
+
+ mutex_lock(&inode->i_mutex);
+
+ if (pos >= i_size_read(inode)) {
+ rc = 0;
+ goto out;
+ }
+
+ ziel = iov->iov_base;
+ todo = min((loff_t) iov->iov_len, i_size_read(inode) - pos);
+
+ for (step = todo; step; step -= size) {
+ size = step;
+ pin = azfs_recherche(inode, AZFS_READ, pos, &size);
+ if (!pin) {
+ rc = -ENOSPC;
+ goto out;
+ }
+ if (copy_to_user(ziel, (void*) pin, size)) {
+ rc = -EFAULT;
+ goto out;
+ }
+
+ iocb->ki_pos += size;
+ pos += size;
+ ziel += size;
+ }
+
+ rc = todo;
+
+out:
+ mutex_unlock(&inode->i_mutex);
+
+ return rc;
+}
+
+/**
+ * azfs_aio_write - aio_write() method for file_operations
+ * @iocb, @iov, @nr_segs, @pos: see file_operations methods
+ */
+static ssize_t
+azfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
+{
+ struct inode *inode;
+ void *quell;
+ unsigned long pin;
+ unsigned long size, todo, step;
+ ssize_t rc;
+
+ inode = iocb->ki_filp->f_mapping->host;
+
+ quell = iov->iov_base;
+ todo = iov->iov_len;
+
+ mutex_lock(&inode->i_mutex);
+
+ for (step = todo; step; step -= size) {
+ size = step;
+ pin = azfs_recherche(inode, AZFS_WRITE, pos, &size);
+ if (!pin) {
+ rc = -ENOSPC;
+ goto out;
+ }
+ if (copy_from_user((void*) pin, quell, size)) {
+ rc = -EFAULT;
+ goto out;
+ }
+
+ iocb->ki_pos += size;
+ pos += size;
+ quell += size;
+ }
+
+ rc = todo;
+
+out:
+ mutex_unlock(&inode->i_mutex);
+
+ return rc;
+}
+
+/**
+ * azfs_open - open() method for file_operations
+ * @inode, @file: see file_operations methods
+ */
+static int
+azfs_open(struct inode *inode, struct file *file)
+{
+ file->private_data = inode;
+
+ if (file->f_flags & O_TRUNC) {
+ i_size_write(inode, 0);
+ inode->i_op->truncate(inode);
+ }
+ if (file->f_flags & O_APPEND)
+ inode->i_fop->llseek(file, 0, SEEK_END);
+
+ return 0;
+}
+
+/**
+ * azfs_mmap - mmap() method for file_operations
+ * @file, @vm: see file_operations methods
+ */
+static int
+azfs_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct azfs_super *super;
+ struct azfs_znode *znode;
+ struct inode *inode;
+ unsigned long cursor, pin;
+ unsigned long todo, size, vm_start;
+ pgprot_t page_prot;
+
+ inode = file->private_data;
+ znode = I2Z(inode);
+ super = inode->i_sb->s_fs_info;
+
+ if (super->block_size < PAGE_SIZE)
+ return -EINVAL;
+
+ cursor = vma->vm_pgoff << super->block_shift;
+ todo = vma->vm_end - vma->vm_start;
+
+ if (cursor + todo > i_size_read(inode))
+ return -EINVAL;
+
+ page_prot = pgprot_val(vma->vm_page_prot);
+ page_prot |= (_PAGE_NO_CACHE | _PAGE_RW);
+ page_prot &= ~_PAGE_GUARDED;
+ vma->vm_page_prot = __pgprot(page_prot);
+
+ vm_start = vma->vm_start;
+ for (size = todo; todo; todo -= size, size = todo) {
+ pin = azfs_recherche(inode, AZFS_MMAP, cursor, &size);
+ if (!pin)
+ return -EAGAIN;
+ pin >>= PAGE_SHIFT;
+ if (remap_pfn_range(vma, vm_start, pin, size, vma->vm_page_prot))
+ return -EAGAIN;
+
+ vm_start += size;
+ cursor += size;
+ }
+
+ return 0;
+}
+
+/**
+ * azfs_truncate - truncate() method for inode_operations
+ * @inode: see inode_operations methods
+ */
+static void
+azfs_truncate(struct inode *inode)
+{
+ struct azfs_super *super;
+ struct azfs_znode *znode;
+ struct azfs_block *block, *ding, *knoten, *west, *east;
+ unsigned long id, count;
+ signed long delta;
+
+ super = inode->i_sb->s_fs_info;
+ znode = I2Z(inode);
+
+ delta = i_size_read(inode) + (super->block_size - 1);
+ delta >>= super->block_shift;
+ delta -= inode->i_blocks;
+
+ if (delta == 0) {
+ znode->size = i_size_read(inode);
+ return;
+ }
+
+ write_lock(&znode->lock);
+
+ while (delta > 0) {
+ west = east = NULL;
+
+ write_lock(&super->lock);
+
+ if (list_empty(&super->block_list)) {
+ write_unlock(&super->lock);
+ break;
+ }
+
+ for (count = delta; count; count--) {
+ for_each_block(block, &super->block_list)
+ if (block->count >= count) {
+ east = block;
+ break;
+ }
+ if (east)
+ break;
+ }
+
+ for_each_block_reverse(block, &znode->block_list) {
+ if (block->id + block->count == east->id)
+ west = block;
+ break;
+ }
+
+ if (east->count == count) {
+ if (west) {
+ west->count += east->count;
+ azfs_block_free(east);
+ } else {
+ azfs_block_move(east, &znode->block_list);
+ }
+ } else {
+ if (west) {
+ west->count += count;
+ } else {
+ if (!azfs_block_init(&znode->block_list,
+ east->id, count)) {
+ write_unlock(&super->lock);
+ break;
+ }
+ }
+
+ east->id += count;
+ east->count -= count;
+ }
+
+ write_unlock(&super->lock);
+
+ inode->i_blocks += count;
+
+ delta -= count;
+ }
+
+ while (delta < 0) {
+ for_each_block_safe_reverse(block, knoten, &znode->block_list) {
+ id = block->id;
+ count = block->count;
+ if ((signed long) count + delta > 0) {
+ block->count += delta;
+ id += block->count;
+ count -= block->count;
+ block = NULL;
+ }
+
+ west = east = NULL;
+
+ write_lock(&super->lock);
+
+ for_each_block(ding, &super->block_list) {
+ if (!west && (ding->id + ding->count == id))
+ west = ding;
+ else if (!east && (id + count == ding->id))
+ east = ding;
+ if (west && east)
+ break;
+ }
+
+ if (west && east) {
+ west->count += count + east->count;
+ azfs_block_free(east);
+ if (block)
+ azfs_block_free(block);
+ } else if (west) {
+ west->count += count;
+ if (block)
+ azfs_block_free(block);
+ } else if (east) {
+ east->id -= count;
+ east->count += count;
+ if (block)
+ azfs_block_free(block);
+ } else {
+ if (!block) {
+ if (!azfs_block_init(&super->block_list,
+ id, count)) {
+ write_unlock(&super->lock);
+ break;
+ }
+ } else {
+ azfs_block_move(block, &super->block_list);
+ }
+ }
+
+ write_unlock(&super->lock);
+
+ inode->i_blocks -= count;
+
+ delta += count;
+
+ break;
+ }
+ }
+
+ write_unlock(&znode->lock);
+
+ znode->size = min(i_size_read(inode),
+ (loff_t) inode->i_blocks << super->block_shift);
+}
+
+/**
+ * azfs_getattr - getattr() method for inode_operations
+ * @mnt, @dentry, @stat: see inode_operations methods
+ */
+static int
+azfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
+{
+ struct azfs_super *super;
+ struct inode *inode;
+ unsigned short shift;
+
+ inode = dentry->d_inode;
+ super = inode->i_sb->s_fs_info;
+
+ generic_fillattr(inode, stat);
+ stat->blocks = inode->i_blocks;
+ shift = super->block_shift - super->sector_shift;
+ if (shift)
+ stat->blocks <<= shift;
+
+ return 0;
+}
+
+static const struct address_space_operations azfs_aops = {
+ .write_begin = simple_write_begin,
+ .write_end = simple_write_end
+};
+
+static struct backing_dev_info azfs_bdi = {
+ .ra_pages = 0,
+ .capabilities = AZFS_BDI_CAPABILITIES
+};
+
+static struct inode_operations azfs_dir_iops = {
+ .create = azfs_create,
+ .lookup = simple_lookup,
+ .link = simple_link,
+ .unlink = simple_unlink,
+ .symlink = azfs_symlink,
+ .mkdir = azfs_mkdir,
+ .rmdir = simple_rmdir,
+ .mknod = azfs_mknod,
+ .rename = simple_rename
+};
+
+static const struct file_operations azfs_reg_fops = {
+ .llseek = generic_file_llseek,
+ .aio_read = azfs_aio_read,
+ .aio_write = azfs_aio_write,
+ .open = azfs_open,
+ .mmap = azfs_mmap,
+ .fsync = simple_sync_file,
+};
+
+static struct inode_operations azfs_reg_iops = {
+ .truncate = azfs_truncate,
+ .getattr = azfs_getattr
+};
+
+/**
+ * azfs_new_inode - cook a new inode
+ * @sb: super-block
+ * @dir: parent directory
+ * @mode: file mode
+ * @dev: to be forwarded to init_special_inode()
+ */
+static struct inode*
+azfs_new_inode(struct super_block *sb, struct inode *dir, int mode, dev_t dev)
+{
+ struct azfs_super *super;
+ struct inode *inode;
+
+ inode = new_inode(sb);
+ if (!inode)
+ return NULL;
+
+ inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+
+ inode->i_mode = mode;
+ if (dir) {
+ dir->i_mtime = dir->i_ctime = inode->i_mtime;
+ inode->i_uid = current->fsuid;
+ if (dir->i_mode & S_ISGID) {
+ if (S_ISDIR(mode))
+ inode->i_mode |= S_ISGID;
+ inode->i_gid = dir->i_gid;
+ } else {
+ inode->i_gid = current->fsgid;
+ }
+ } else {
+ super = sb->s_fs_info;
+ inode->i_uid = super->uid;
+ inode->i_gid = super->gid;
+ }
+
+ inode->i_blocks = 0;
+ inode->i_mapping->a_ops = &azfs_aops;
+ inode->i_mapping->backing_dev_info = &azfs_bdi;
+
+ switch (mode & S_IFMT) {
+ case S_IFDIR:
+ inode->i_op = &azfs_dir_iops;
+ inode->i_fop = &simple_dir_operations;
+ inc_nlink(inode);
+ break;
+
+ case S_IFREG:
+ inode->i_op = &azfs_reg_iops;
+ inode->i_fop = &azfs_reg_fops;
+ break;
+
+ case S_IFLNK:
+ inode->i_op = &page_symlink_inode_operations;
+ break;
+
+ default:
+ init_special_inode(inode, mode, dev);
+ break;
+ }
+
+ return inode;
+}
+
+/**
+ * azfs_alloc_inode - alloc_inode() method for super_operations
+ * @sb: see super_operations methods
+ */
+static struct inode*
+azfs_alloc_inode(struct super_block *sb)
+{
+ struct azfs_znode *znode;
+
+ znode = kmem_cache_alloc(azfs_znode_cache, GFP_KERNEL);
+
+ INIT_LIST_HEAD(&znode->block_list);
+ rwlock_init(&znode->lock);
+
+ inode_init_once(&znode->vfs_inode);
+
+ return znode ? &znode->vfs_inode : NULL;
+}
+
+/**
+ * azfs_destroy_inode - destroy_inode() method for super_operations
+ * @inode: see super_operations methods
+ */
+static void
+azfs_destroy_inode(struct inode *inode)
+{
+ kmem_cache_free(azfs_znode_cache, I2Z(inode));
+}
+
+/**
+ * azfs_delete_inode - delete_inode() method for super_operations
+ * @inode: see super_operations methods
+ */
+static void
+azfs_delete_inode(struct inode *inode)
+{
+ if (S_ISREG(inode->i_mode)) {
+ i_size_write(inode, 0);
+ azfs_truncate(inode);
+ }
+ truncate_inode_pages(&inode->i_data, 0);
+ clear_inode(inode);
+}
+
+/**
+ * azfs_statfs - statfs() method for super_operations
+ * @dentry, @stat: see super_operations methods
+ */
+static int
+azfs_statfs(struct dentry *dentry, struct kstatfs *stat)
+{
+ struct super_block *sb;
+ struct azfs_super *super;
+ struct inode *inode;
+ unsigned long inodes, blocks;
+
+ sb = dentry->d_sb;
+ super = sb->s_fs_info;
+
+ inodes = blocks = 0;
+ mutex_lock(&sb->s_lock);
+ list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
+ inodes++;
+ blocks += inode->i_blocks;
+ }
+ mutex_unlock(&sb->s_lock);
+
+ stat->f_type = AZFS_SUPERBLOCK_MAGIC;
+ stat->f_bsize = super->block_size;
+ stat->f_blocks = super->media_size >> super->block_shift;
+ stat->f_bfree = stat->f_blocks - blocks;
+ stat->f_bavail = stat->f_blocks - blocks;
+ stat->f_files = inodes + blocks;
+ stat->f_ffree = blocks + 1;
+ stat->f_namelen = NAME_MAX;
+
+ return 0;
+}
+
+static struct super_operations azfs_ops = {
+ .alloc_inode = azfs_alloc_inode,
+ .destroy_inode = azfs_destroy_inode,
+ .drop_inode = generic_delete_inode,
+ .delete_inode = azfs_delete_inode,
+ .statfs = azfs_statfs
+};
+
+enum {
+ Opt_blocksize_short,
+ Opt_blocksize_long,
+ Opt_uid,
+ Opt_gid,
+ Opt_err
+};
+
+static match_table_t tokens = {
+ {Opt_blocksize_short, "bs=%u"},
+ {Opt_blocksize_long, "blocksize=%u"},
+ {Opt_uid, "uid=%u"},
+ {Opt_gid, "gid=%u"},
+ {Opt_err, NULL}
+};
+
+/**
+ * azfs_parse_mount_parameters - parse options given to mount with -o
+ * @sb: super block
+ * @options: comma separated options
+ */
+static int
+azfs_parse_mount_parameters(struct super_block *sb, char *options)
+{
+ struct azfs_super *super;
+ char *option;
+ int token, value;
+ substring_t args[MAX_OPT_ARGS];
+
+ super = sb->s_fs_info;
+
+ while ((option = strsep(&options, ",")) != NULL) {
+ if (!*option)
+ continue;
+
+ token = match_token(option, tokens, args);
+ switch (token) {
+ case Opt_blocksize_short:
+ case Opt_blocksize_long:
+ if (match_int(&args[0], &value))
+ goto syntax_error;
+ super->block_size = value;
+ break;
+
+ case Opt_uid:
+ if (match_int(&args[0], &value))
+ goto syntax_error;
+ super->uid = value;
+ break;
+
+ case Opt_gid:
+ if (match_int(&args[0], &value))
+ goto syntax_error;
+ super->gid = value;
+ break;
+
+ default:
+ goto syntax_error;
+ }
+ }
+
+ return 1;
+
+syntax_error:
+ printk(KERN_ERR "%s: invalid mount option\n",
+ AZFS_FILESYSTEM_NAME);
+
+ return 0;
+}
+
+/**
+ * azfs_fill_super - fill_super routine for get_sb
+ * @sb, @data, @silent: see file_system_type methods
+ */
+static int
+azfs_fill_super(struct super_block *sb, void *data, int silent)
+{
+ struct gendisk *disk;
+ struct azfs_super *super = NULL, *knoten;
+ struct azfs_block *block = NULL;
+ struct inode *inode = NULL;
+ void *kaddr;
+ unsigned long pfn;
+ int rc;
+
+ BUG_ON(!sb->s_bdev);
+
+ disk = sb->s_bdev->bd_disk;
+
+ if (!disk || !disk->queue) {
+ printk(KERN_ERR "%s needs a block device which has a gendisk "
+ "with a queue\n",
+ AZFS_FILESYSTEM_NAME);
+ return -ENOSYS;
+ }
+
+ if (!disk->fops->direct_access) {
+ printk(KERN_ERR "%s needs a block device with a "
+ "direct_access() method\n",
+ AZFS_FILESYSTEM_NAME);
+ return -ENOSYS;
+ }
+
+ if (!get_device(disk->driverfs_dev)) {
+ printk(KERN_ERR "%s cannot get reference to device driver\n",
+ AZFS_FILESYSTEM_NAME);
+ return -EFAULT;
+ }
+
+ sb->s_magic = AZFS_SUPERBLOCK_MAGIC;
+ sb->s_flags = AZFS_SUPERBLOCK_FLAGS;
+ sb->s_op = &azfs_ops;
+ sb->s_maxbytes = get_capacity(disk) * disk->queue->hardsect_size;
+ sb->s_time_gran = 1;
+
+ spin_lock(&super_list.lock);
+ list_for_each_entry(knoten, &super_list.head, list)
+ if (knoten->blkdev == sb->s_bdev) {
+ super = knoten;
+ break;
+ }
+ spin_unlock(&super_list.lock);
+
+ if (super) {
+ if (strlen((char*) data))
+ printk(KERN_WARNING "/dev/%s was already mounted with "
+ "%s before, it will be mounted with "
+ "mount options used last time, "
+ "options just given would be ignored\n",
+ disk->disk_name, AZFS_FILESYSTEM_NAME);
+ sb->s_fs_info = super;
+ } else {
+ super = kzalloc(sizeof(struct azfs_super), GFP_KERNEL);
+ if (!super) {
+ rc = -ENOMEM;
+ goto failed;
+ }
+ sb->s_fs_info = super;
+
+ if (!azfs_parse_mount_parameters(sb, (char*) data)) {
+ rc = -EINVAL;
+ goto failed;
+ }
+
+ inode = azfs_new_inode(sb, NULL, S_IFDIR | S_IRWXUGO, 0);
+ if (!inode) {
+ rc = -ENOMEM;
+ goto failed;
+ }
+
+ super->root = d_alloc_root(inode);
+ if (!super->root) {
+ rc = -ENOMEM;
+ goto failed;
+ }
+ dget(super->root);
+
+ INIT_LIST_HEAD(&super->list);
+ INIT_LIST_HEAD(&super->block_list);
+ rwlock_init(&super->lock);
+
+ super->media_size = sb->s_maxbytes;
+
+ if (!super->block_size)
+ super->block_size = sb->s_blocksize;
+ super->block_shift = blksize_bits(super->block_size);
+
+ super->sector_size = disk->queue->hardsect_size;
+ super->sector_shift = blksize_bits(super->sector_size);
+
+ super->blkdev = sb->s_bdev;
+
+ block = azfs_block_init(&super->block_list,
+ 0, super->media_size >> super->block_shift);
+ if (!block) {
+ rc = -ENOMEM;
+ goto failed;
+ }
+
+ rc = disk->fops->direct_access(super->blkdev, 0, &kaddr, &pfn);
+ if (rc < 0) {
+ rc = -EFAULT;
+ goto failed;
+ }
+ super->ph_addr = (unsigned long) kaddr;
+
+ super->io_addr = (unsigned long) ioremap_flags(
+ super->ph_addr, super->media_size, _PAGE_NO_CACHE);
+ if (!super->io_addr) {
+ rc = -EFAULT;
+ goto failed;
+ }
+
+ spin_lock(&super_list.lock);
+ list_add(&super->list, &super_list.head);
+ spin_unlock(&super_list.lock);
+ }
+
+ sb->s_root = super->root;
+ disk->driverfs_dev->driver_data = super;
+ disk->driverfs_dev->platform_data = sb;
+
+ if (super->block_size < PAGE_SIZE)
+ printk(KERN_INFO "Block size on %s is smaller then system "
+ "page size: mmap() would not be supported\n",
+ disk->disk_name);
+
+ return 0;
+
+failed:
+ if (super) {
+ sb->s_root = NULL;
+ sb->s_fs_info = NULL;
+ if (block)
+ azfs_block_free(block);
+ if (super->root)
+ dput(super->root);
+ if (inode)
+ iput(inode);
+ disk->driverfs_dev->driver_data = NULL;
+ kfree(super);
+ disk->driverfs_dev->platform_data = NULL;
+ put_device(disk->driverfs_dev);
+ }
+
+ return rc;
+}
+
+/**
+ * azfs_get_sb - get_sb() method for file_system_type
+ * @fs_type, @flags, @dev_name, @data, @mount: see file_system_type methods
+ */
+static int
+azfs_get_sb(struct file_system_type *fs_type, int flags,
+ const char *dev_name, void *data, struct vfsmount *mount)
+{
+ return get_sb_bdev(fs_type, flags,
+ dev_name, data, azfs_fill_super, mount);
+}
+
+/**
+ * azfs_kill_sb - kill_sb() method for file_system_type
+ * @sb: see file_system_type methods
+ */
+static void
+azfs_kill_sb(struct super_block *sb)
+{
+ sb->s_root = NULL;
+ kill_block_super(sb);
+}
+
+static struct file_system_type azfs_fs = {
+ .owner = THIS_MODULE,
+ .name = AZFS_FILESYSTEM_NAME,
+ .get_sb = azfs_get_sb,
+ .kill_sb = azfs_kill_sb,
+ .fs_flags = AZFS_FILESYSTEM_FLAGS
+};
+
+/**
+ * azfs_init
+ */
+static int __init
+azfs_init(void)
+{
+ int rc;
+
+ INIT_LIST_HEAD(&super_list.head);
+ spin_lock_init(&super_list.lock);
+
+ azfs_znode_cache = kmem_cache_create("azfs_znode_cache",
+ sizeof(struct azfs_znode), 0, AZFS_CACHE_FLAGS, NULL);
+ if (!azfs_znode_cache) {
+ printk(KERN_ERR "Could not allocate inode cache for %s\n",
+ AZFS_FILESYSTEM_NAME);
+ rc = -ENOMEM;
+ goto failed;
+ }
+
+ azfs_block_cache = kmem_cache_create("azfs_block_cache",
+ sizeof(struct azfs_block), 0, AZFS_CACHE_FLAGS, NULL);
+ if (!azfs_block_cache) {
+ printk(KERN_ERR "Could not allocate block cache for %s\n",
+ AZFS_FILESYSTEM_NAME);
+ rc = -ENOMEM;
+ goto failed;
+ }
+
+ rc = register_filesystem(&azfs_fs);
+ if (rc != 0) {
+ printk(KERN_ERR "Could not register %s\n",
+ AZFS_FILESYSTEM_NAME);
+ goto failed;
+ }
+
+ return 0;
+
+failed:
+ if (azfs_block_cache)
+ kmem_cache_destroy(azfs_block_cache);
+
+ if (azfs_znode_cache)
+ kmem_cache_destroy(azfs_znode_cache);
+
+ return rc;
+}
+
+/**
+ * azfs_exit
+ */
+static void __exit
+azfs_exit(void)
+{
+ struct azfs_super *super, *SUPER;
+ struct azfs_block *block, *knoten;
+ struct gendisk *disk;
+
+ spin_lock(&super_list.lock);
+ list_for_each_entry_safe(super, SUPER, &super_list.head, list) {
+ disk = super->blkdev->bd_disk;
+ list_del(&super->list);
+ iounmap((void*) super->io_addr);
+ write_lock(&super->lock);
+ for_each_block_safe(block, knoten, &super->block_list)
+ azfs_block_free(block);
+ write_unlock(&super->lock);
+ disk->driverfs_dev->driver_data = NULL;
+ disk->driverfs_dev->platform_data = NULL;
+ kfree(super);
+ put_device(disk->driverfs_dev);
+ }
+ spin_unlock(&super_list.lock);
+
+ unregister_filesystem(&azfs_fs);
+
+ kmem_cache_destroy(azfs_block_cache);
+ kmem_cache_destroy(azfs_znode_cache);
+}
+
+module_init(azfs_init);
+module_exit(azfs_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Maxim Shchetynin <maxim@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Non-buffered file system for IO devices");
Mit freundlichen Grüßen / met vriendelijke groeten / avec regards
Maxim V. Shchetynin
Linux Kernel Entwicklung
IBM Deutschland Entwicklung GmbH
Linux für Cell, Abteilung 3250
Schönaicher Straße 220
71032 Böblingen
Vorsitzender des Aufsichtsrats: Johann Weihen
Geschäftsführung: Herbert Kircher
Sitz der Gesellschaft: Böblingen
Registriergericht: Amtsgericht Stuttgart, HRB 243294
Fahr nur so schnell wie dein Schutzengel fliegen kann!
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