[PATCH] bdev: add I_BDEV()

From: viro@parcelfarce.linux.theplanet.co.uk <viro@parcelfarce.linux.theplanet.co.uk>

For bdevfs inodes (ones created along with struct block_device by
fs/block_dev.c) we have inode->i_bdev equal to &BDEV_I(inode)->bdev (i.e.
it's at the constant offset from inode).  New helper added for such inodes
(I_BDEV(inode)).  A bunch of places (mostly in block_dev.c) switched to use
of that helper.  A bunch of places that used

	file->f_dentry->d_inode->i_bdev->bd_inode

switched to

	file->f_mapping->host

- those expressions are equal whenever the former is valid.

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 5565110f8561949d5a022148522baa2e608c6161..87f8c2527ca8fb92a4c7783a4d8cb719b0ca2d3d 100644 (file)
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -683,7 +683,7 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
                lo_flags |= LO_FLAGS_READ_ONLY;
 
        if (S_ISBLK(inode->i_mode)) {
-               lo_device = inode->i_bdev;
+               lo_device = I_BDEV(inode);
                if (lo_device == bdev) {
                        error = -EBUSY;
                        goto out_putf;

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 3bfe77ec0864ade7b01037875ce0fe11eab617e8..c2649835bac09d26b880d2c7f89da023bc5e2b15 100644 (file)
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -25,6 +25,22 @@
 #include <linux/namei.h>
 #include <asm/uaccess.h>
 
+struct bdev_inode {
+       struct block_device bdev;
+       struct inode vfs_inode;
+};
+
+static inline struct bdev_inode *BDEV_I(struct inode *inode)
+{
+       return container_of(inode, struct bdev_inode, vfs_inode);
+}
+
+inline struct block_device *I_BDEV(struct inode *inode)
+{
+       return &BDEV_I(inode)->bdev;
+}
+
+EXPORT_SYMBOL(I_BDEV);
 
 static sector_t max_block(struct block_device *bdev)
 {
@@ -100,10 +116,10 @@ static int
 blkdev_get_block(struct inode *inode, sector_t iblock,
                struct buffer_head *bh, int create)
 {
-       if (iblock >= max_block(inode->i_bdev))
+       if (iblock >= max_block(I_BDEV(inode)))
                return -EIO;
 
-       bh->b_bdev = inode->i_bdev;
+       bh->b_bdev = I_BDEV(inode);
        bh->b_blocknr = iblock;
        set_buffer_mapped(bh);
        return 0;
@@ -113,10 +129,10 @@ static int
 blkdev_get_blocks(struct inode *inode, sector_t iblock,
                unsigned long max_blocks, struct buffer_head *bh, int create)
 {
-       if ((iblock + max_blocks) > max_block(inode->i_bdev))
+       if ((iblock + max_blocks) > max_block(I_BDEV(inode)))
                return -EIO;
 
-       bh->b_bdev = inode->i_bdev;
+       bh->b_bdev = I_BDEV(inode);
        bh->b_blocknr = iblock;
        bh->b_size = max_blocks << inode->i_blkbits;
        set_buffer_mapped(bh);
@@ -130,7 +146,7 @@ blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
        struct file *file = iocb->ki_filp;
        struct inode *inode = file->f_mapping->host;
 
-       return blockdev_direct_IO(rw, iocb, inode, inode->i_bdev, iov, offset,
+       return blockdev_direct_IO(rw, iocb, inode, I_BDEV(inode), iov, offset,
                                nr_segs, blkdev_get_blocks, NULL);
 }
 
@@ -161,11 +177,10 @@ static int blkdev_commit_write(struct file *file, struct page *page, unsigned fr
  */
 static loff_t block_llseek(struct file *file, loff_t offset, int origin)
 {
-       struct inode *bd_inode;
+       struct inode *bd_inode = file->f_mapping->host;
        loff_t size;
        loff_t retval;
 
-       bd_inode = file->f_dentry->d_inode->i_bdev->bd_inode;
        down(&bd_inode->i_sem);
        size = i_size_read(bd_inode);
 
@@ -188,15 +203,13 @@ static loff_t block_llseek(struct file *file, loff_t offset, int origin)
 }
        
 /*
- *     Filp may be NULL when we are called by an msync of a vma
- *     since the vma has no handle.
+ *     Filp is never NULL; the only case when ->fsync() is called with
+ *     NULL first argument is nfsd_sync_dir() and that's not a directory.
  */
  
 static int block_fsync(struct file *filp, struct dentry *dentry, int datasync)
 {
-       struct inode * inode = dentry->d_inode;
-
-       return sync_blockdev(inode->i_bdev);
+       return sync_blockdev(I_BDEV(filp->f_mapping->host));
 }
 
 /*
@@ -206,16 +219,6 @@ static int block_fsync(struct file *filp, struct dentry *dentry, int datasync)
 static spinlock_t bdev_lock __cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED;
 static kmem_cache_t * bdev_cachep;
 
-struct bdev_inode {
-       struct block_device bdev;
-       struct inode vfs_inode;
-};
-
-static inline struct bdev_inode *BDEV_I(struct inode *inode)
-{
-       return container_of(inode, struct bdev_inode, vfs_inode);
-}
-
 static struct inode *bdev_alloc_inode(struct super_block *sb)
 {
        struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, SLAB_KERNEL);
@@ -735,11 +738,12 @@ int blkdev_put(struct block_device *bdev, int kind)
 
 EXPORT_SYMBOL(blkdev_put);
 
-int blkdev_close(struct inode * inode, struct file * filp)
+static int blkdev_close(struct inode * inode, struct file * filp)
 {
-       if (inode->i_bdev->bd_holder == filp)
-               bd_release(inode->i_bdev);
-       return blkdev_put(inode->i_bdev, BDEV_FILE);
+       struct block_device *bdev = I_BDEV(filp->f_mapping->host);
+       if (bdev->bd_holder == filp)
+               bd_release(bdev);
+       return blkdev_put(bdev, BDEV_FILE);
 }
 
 static ssize_t blkdev_file_write(struct file *file, const char __user *buf,
@@ -758,6 +762,11 @@ static ssize_t blkdev_file_aio_write(struct kiocb *iocb, const char __user *buf,
        return generic_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos);
 }
 
+static int block_ioctl(struct inode *inode, struct file *file, unsigned cmd,
+                       unsigned long arg)
+{
+       return blkdev_ioctl(file->f_mapping->host, file, cmd, arg);
+}
 
 struct address_space_operations def_blk_aops = {
        .readpage       = blkdev_readpage,
@@ -779,7 +788,7 @@ struct file_operations def_blk_fops = {
        .aio_write      = blkdev_file_aio_write, 
        .mmap           = generic_file_mmap,
        .fsync          = block_fsync,
-       .ioctl          = blkdev_ioctl,
+       .ioctl          = block_ioctl,
        .readv          = generic_file_readv,
        .writev         = generic_file_writev,
        .sendfile       = generic_file_sendfile,

diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index db1dfe91c2a4b3257f08e9b6b1343906a434b1b3..c86cd729e3a2343ffaf785021633785c3f897565 100644 (file)
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -1937,18 +1937,13 @@ static int journal_init_dev( struct super_block *super,
 
        journal -> j_dev_file = filp_open( jdev_name, 0, 0 );
        if( !IS_ERR( journal -> j_dev_file ) ) {
-               struct inode *jdev_inode;
-
-               jdev_inode = journal -> j_dev_file -> f_dentry -> d_inode;
-               journal -> j_dev_bd = jdev_inode -> i_bdev;
+               struct inode *jdev_inode = journal->j_dev_file->f_mapping->host;
                if( !S_ISBLK( jdev_inode -> i_mode ) ) {
                        printk( "journal_init_dev: '%s' is not a block device\n", jdev_name );
                        result = -ENOTBLK;
-               } else if( jdev_inode -> i_bdev == NULL ) {
-                       printk( "journal_init_dev: bdev uninitialized for '%s'\n", jdev_name );
-                       result = -ENOMEM;
                } else  {
                        /* ok */
+                       journal->j_dev_bd = I_BDEV(jdev_inode);
                        set_blocksize(journal->j_dev_bd, super->s_blocksize);
                }
        } else {

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 2880d702043ed97856126542b85df7e0b87e924b..8863f93617ba7195efbc5548989f8e75a67d2416 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -480,6 +480,8 @@ static inline unsigned imajor(struct inode *inode)
        return MAJOR(inode->i_rdev);
 }
 
+extern struct block_device *I_BDEV(struct inode *inode);
+
 struct fown_struct {
        rwlock_t lock;          /* protects pid, uid, euid fields */
        int pid;                /* pid or -pgrp where SIGIO should be sent */
@@ -1128,7 +1130,6 @@ extern struct block_device *bdget(dev_t);
 extern void bd_forget(struct inode *inode);
 extern void bdput(struct block_device *);
 extern int blkdev_open(struct inode *, struct file *);
-extern int blkdev_close(struct inode *, struct file *);
 extern struct block_device *open_by_devnum(dev_t, unsigned, int);
 extern struct file_operations def_blk_fops;
 extern struct address_space_operations def_blk_aops;

diff --git a/mm/filemap.c b/mm/filemap.c
index d9368c9368de431f51d80433a799287aac01d31d..b4d34de279a88c489044fc9d9d914767800781ec 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1690,7 +1690,7 @@ inline int generic_write_checks(struct file *file, loff_t *pos, size_t *count, i
                        *count = inode->i_sb->s_maxbytes - *pos;
        } else {
                loff_t isize;
-               if (bdev_read_only(inode->i_bdev))
+               if (bdev_read_only(I_BDEV(inode)))
                        return -EPERM;
                isize = i_size_read(inode);
                if (*pos >= isize) {

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 46d1e0f9d26ad127900b8a6e80bb07b722cbf437..112117a5d66c845606f7ea9a7da3efc2f812ff1d 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1100,8 +1100,7 @@ asmlinkage long sys_swapoff(const char __user * specialfile)
        swap_list_unlock();
        vfree(swap_map);
        if (S_ISBLK(mapping->host->i_mode)) {
-               struct block_device *bdev;
-               bdev = mapping->host->i_bdev;
+               struct block_device *bdev = I_BDEV(mapping->host);
                set_blocksize(bdev, p->old_block_size);
                bd_release(bdev);
        } else {
@@ -1294,14 +1293,14 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
 
        error = -EINVAL;
        if (S_ISBLK(inode->i_mode)) {
-               bdev = inode->i_bdev;
+               bdev = I_BDEV(inode);
                error = bd_claim(bdev, sys_swapon);
                if (error < 0) {
                        bdev = NULL;
                        goto bad_swap;
                }
                p->old_block_size = block_size(bdev);
-               error = set_blocksize(inode->i_bdev, PAGE_SIZE);
+               error = set_blocksize(bdev, PAGE_SIZE);
                if (error < 0)
                        goto bad_swap;
                p->bdev = bdev;