new helper: ihold()

Clones an existing reference to inode; caller must already hold one.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

35 files changed, 52 insertions, 45 deletions

diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 9e670d527646..ef5905f7c8a3 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -1789,9 +1789,10 @@ v9fs_vfs_link_dotl(struct dentry *old_dentry, struct inode *dir,
 		kfree(st);
 	} else {
 		/* Caching disabled. No need to get upto date stat info.
-		 * This dentry will be released immediately. So, just i_count++
+		 * This dentry will be released immediately. So, just hold the
+		 * inode
 		 */
-		atomic_inc(&old_dentry->d_inode->i_count);
+		ihold(old_dentry->d_inode);
 	}
 
 	dentry->d_op = old_dentry->d_op;
diff --git a/fs/affs/inode.c b/fs/affs/inode.c
index 3a0fdec175ba..5d828903ac69 100644
--- a/fs/affs/inode.c
+++ b/fs/affs/inode.c
@@ -388,7 +388,7 @@ affs_add_entry(struct inode *dir, struct inode *inode, struct dentry *dentry, s3
 		affs_adjust_checksum(inode_bh, block - be32_to_cpu(chain));
 		mark_buffer_dirty_inode(inode_bh, inode);
 		inode->i_nlink = 2;
-		atomic_inc(&inode->i_count);
+		ihold(inode);
 	}
 	affs_fix_checksum(sb, bh);
 	mark_buffer_dirty_inode(bh, inode);
diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 0d38c09bd55e..5439e1bc9a86 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -1045,7 +1045,7 @@ static int afs_link(struct dentry *from, struct inode *dir,
 	if (ret < 0)
 		goto link_error;
 
-	atomic_inc(&vnode->vfs_inode.i_count);
+	ihold(&vnode->vfs_inode);
 	d_instantiate(dentry, &vnode->vfs_inode);
 	key_put(key);
 	_leave(" = 0");
diff --git a/fs/aio.c b/fs/aio.c
index 9e319a04780e..8c8f6c5b6d79 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1553,10 +1553,9 @@ static void aio_batch_add(struct address_space *mapping,
 	 *
 	 * When we're called, we always have a reference
 	 * on the file, so we must always have a reference
-	 * on the inode, so igrab must always just
-	 * bump the count and move on.
+	 * on the inode, so ihold() is safe here.
 	 */
-	atomic_inc(&mapping->host->i_count);
+	ihold(mapping->host);
 	abe->mapping = mapping;
 	hlist_add_head(&abe->list, &batch_hash[bucket]);
 	return;
diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c
index e4b75d6eda83..9c8e87b0361f 100644
--- a/fs/anon_inodes.c
+++ b/fs/anon_inodes.c
@@ -111,10 +111,9 @@ struct file *anon_inode_getfile(const char *name,
 	path.mnt = mntget(anon_inode_mnt);
 	/*
 	 * We know the anon_inode inode count is always greater than zero,
-	 * so we can avoid doing an igrab() and we can use an open-coded
-	 * atomic_inc().
+	 * so ihold() is safe.
 	 */
-	atomic_inc(&anon_inode_inode->i_count);
+	ihold(anon_inode_inode);
 
 	path.dentry->d_op = &anon_inodefs_dentry_operations;
 	d_instantiate(path.dentry, anon_inode_inode);
diff --git a/fs/bfs/dir.c b/fs/bfs/dir.c
index d967e052b779..685ecff3ab31 100644
--- a/fs/bfs/dir.c
+++ b/fs/bfs/dir.c
@@ -176,7 +176,7 @@ static int bfs_link(struct dentry *old, struct inode *dir,
 	inc_nlink(inode);
 	inode->i_ctime = CURRENT_TIME_SEC;
 	mark_inode_dirty(inode);
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 	d_instantiate(new, inode);
 	mutex_unlock(&info->bfs_lock);
 	return 0;
diff --git a/fs/block_dev.c b/fs/block_dev.c
index b737451e2e9d..81972eb34b39 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -550,7 +550,7 @@ EXPORT_SYMBOL(bdget);
  */
 struct block_device *bdgrab(struct block_device *bdev)
 {
-	atomic_inc(&bdev->bd_inode->i_count);
+	ihold(bdev->bd_inode);
 	return bdev;
 }
 
@@ -580,7 +580,7 @@ static struct block_device *bd_acquire(struct inode *inode)
 	spin_lock(&bdev_lock);
 	bdev = inode->i_bdev;
 	if (bdev) {
-		atomic_inc(&bdev->bd_inode->i_count);
+		ihold(bdev->bd_inode);
 		spin_unlock(&bdev_lock);
 		return bdev;
 	}
@@ -591,12 +591,12 @@ static struct block_device *bd_acquire(struct inode *inode)
 		spin_lock(&bdev_lock);
 		if (!inode->i_bdev) {
 			/*
-			 * We take an additional bd_inode->i_count for inode,
+			 * We take an additional reference to bd_inode,
 			 * and it's released in clear_inode() of inode.
 			 * So, we can access it via ->i_mapping always
 			 * without igrab().
 			 */
-			atomic_inc(&bdev->bd_inode->i_count);
+			ihold(bdev->bd_inode);
 			inode->i_bdev = bdev;
 			inode->i_mapping = bdev->bd_inode->i_mapping;
 			list_add(&inode->i_devices, &bdev->bd_inodes);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index f6f2a0da2695..64f99cf69ce0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4758,7 +4758,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 	}
 
 	btrfs_set_trans_block_group(trans, dir);
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 
 	err = btrfs_add_nondir(trans, dentry, inode, 1, index);
 
diff --git a/fs/coda/dir.c b/fs/coda/dir.c
index 96fbeab77f2f..5d8b35539601 100644
--- a/fs/coda/dir.c
+++ b/fs/coda/dir.c
@@ -276,7 +276,7 @@ static int coda_link(struct dentry *source_de, struct inode *dir_inode,
 	}
 
 	coda_dir_update_mtime(dir_inode);
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 	d_instantiate(de, inode);
 	inc_nlink(inode);
 	return 0;
diff --git a/fs/exofs/namei.c b/fs/exofs/namei.c
index b7dd0c236863..264e95d02830 100644
--- a/fs/exofs/namei.c
+++ b/fs/exofs/namei.c
@@ -153,7 +153,7 @@ static int exofs_link(struct dentry *old_dentry, struct inode *dir,
 
 	inode->i_ctime = CURRENT_TIME;
 	inode_inc_link_count(inode);
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 
 	return exofs_add_nondir(dentry, inode);
 }
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index 71efb0e9a3f2..f8aecd2e3297 100644
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -206,7 +206,7 @@ static int ext2_link (struct dentry * old_dentry, struct inode * dir,
 
 	inode->i_ctime = CURRENT_TIME_SEC;
 	inode_inc_link_count(inode);
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 
 	err = ext2_add_link(dentry, inode);
 	if (!err) {
diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c
index 2b35ddb70d65..bce9dce639b8 100644
--- a/fs/ext3/namei.c
+++ b/fs/ext3/namei.c
@@ -2260,7 +2260,7 @@ retry:
 
 	inode->i_ctime = CURRENT_TIME_SEC;
 	inc_nlink(inode);
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 
 	err = ext3_add_entry(handle, dentry, inode);
 	if (!err) {
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 314c0d3b3fa9..bd39885b5998 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2312,7 +2312,7 @@ retry:
 
 	inode->i_ctime = ext4_current_time(inode);
 	ext4_inc_count(handle, inode);
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 
 	err = ext4_add_entry(handle, dentry, inode);
 	if (!err) {
diff --git a/fs/gfs2/ops_inode.c b/fs/gfs2/ops_inode.c
index 48a274f1674c..12cbea7502c2 100644
--- a/fs/gfs2/ops_inode.c
+++ b/fs/gfs2/ops_inode.c
@@ -255,7 +255,7 @@ out_parent:
 	gfs2_holder_uninit(ghs);
 	gfs2_holder_uninit(ghs + 1);
 	if (!error) {
-		atomic_inc(&inode->i_count);
+		ihold(inode);
 		d_instantiate(dentry, inode);
 		mark_inode_dirty(inode);
 	}
diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c
index d236d85ec9d7..e318bbc0daf6 100644
--- a/fs/hfsplus/dir.c
+++ b/fs/hfsplus/dir.c
@@ -286,7 +286,7 @@ static int hfsplus_link(struct dentry *src_dentry, struct inode *dst_dir,
 
 	inc_nlink(inode);
 	hfsplus_instantiate(dst_dentry, inode, cnid);
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 	inode->i_ctime = CURRENT_TIME_SEC;
 	mark_inode_dirty(inode);
 	sbi->file_count++;
diff --git a/fs/inode.c b/fs/inode.c
index 430d70f2abe7..05ea293d5f32 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -320,6 +320,15 @@ void __iget(struct inode *inode)
 	atomic_inc(&inode->i_count);
 }
 
+/*
+ * get additional reference to inode; caller must already hold one.
+ */
+void ihold(struct inode *inode)
+{
+	WARN_ON(atomic_inc_return(&inode->i_count) < 2);
+}
+EXPORT_SYMBOL(ihold);
+
 static void inode_lru_list_add(struct inode *inode)
 {
 	if (list_empty(&inode->i_list)) {
diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c
index ed78a3cf3cb0..79121aa5858b 100644
--- a/fs/jffs2/dir.c
+++ b/fs/jffs2/dir.c
@@ -289,7 +289,7 @@ static int jffs2_link (struct dentry *old_dentry, struct inode *dir_i, struct de
 		mutex_unlock(&f->sem);
 		d_instantiate(dentry, old_dentry->d_inode);
 		dir_i->i_mtime = dir_i->i_ctime = ITIME(now);
-		atomic_inc(&old_dentry->d_inode->i_count);
+		ihold(old_dentry->d_inode);
 	}
 	return ret;
 }
@@ -864,7 +864,7 @@ static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
 		printk(KERN_NOTICE "jffs2_rename(): Link succeeded, unlink failed (err %d). You now have a hard link\n", ret);
 		/* Might as well let the VFS know */
 		d_instantiate(new_dentry, old_dentry->d_inode);
-		atomic_inc(&old_dentry->d_inode->i_count);
+		ihold(old_dentry->d_inode);
 		new_dir_i->i_mtime = new_dir_i->i_ctime = ITIME(now);
 		return ret;
 	}
diff --git a/fs/jfs/jfs_txnmgr.c b/fs/jfs/jfs_txnmgr.c
index d945ea76b445..9466957ec841 100644
--- a/fs/jfs/jfs_txnmgr.c
+++ b/fs/jfs/jfs_txnmgr.c
@@ -1279,7 +1279,7 @@ int txCommit(tid_t tid,		/* transaction identifier */
 	 * lazy commit thread finishes processing
 	 */
 	if (tblk->xflag & COMMIT_DELETE) {
-		atomic_inc(&tblk->u.ip->i_count);
+		ihold(tblk->u.ip);
 		/*
 		 * Avoid a rare deadlock
 		 *
diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
index a9cf8e8675be..231ca4af9bce 100644
--- a/fs/jfs/namei.c
+++ b/fs/jfs/namei.c
@@ -839,7 +839,7 @@ static int jfs_link(struct dentry *old_dentry,
 	ip->i_ctime = CURRENT_TIME;
 	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 	mark_inode_dirty(dir);
-	atomic_inc(&ip->i_count);
+	ihold(ip);
 
 	iplist[0] = ip;
 	iplist[1] = dir;
diff --git a/fs/libfs.c b/fs/libfs.c
index 2dbf4877d7ef..304a5132ca27 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -255,7 +255,7 @@ int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *den
 
 	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 	inc_nlink(inode);
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 	dget(dentry);
 	d_instantiate(dentry, inode);
 	return 0;
diff --git a/fs/logfs/dir.c b/fs/logfs/dir.c
index 1eb4e89e045b..409dfd65e9a1 100644
--- a/fs/logfs/dir.c
+++ b/fs/logfs/dir.c
@@ -569,7 +569,7 @@ static int logfs_link(struct dentry *old_dentry, struct inode *dir,
 		return -EMLINK;
 
 	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 	inode->i_nlink++;
 	mark_inode_dirty_sync(inode);
 
diff --git a/fs/minix/namei.c b/fs/minix/namei.c
index f3f3578393a4..c0d35a3accef 100644
--- a/fs/minix/namei.c
+++ b/fs/minix/namei.c
@@ -101,7 +101,7 @@ static int minix_link(struct dentry * old_dentry, struct inode * dir,
 
 	inode->i_ctime = CURRENT_TIME_SEC;
 	inode_inc_link_count(inode);
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 	return add_nondir(dentry, inode);
 }
 
diff --git a/fs/namei.c b/fs/namei.c
index f1ef97dbc6c4..f7dbc06857ab 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2285,7 +2285,7 @@ static long do_unlinkat(int dfd, const char __user *pathname)
 			goto slashes;
 		inode = dentry->d_inode;
 		if (inode)
-			atomic_inc(&inode->i_count);
+			ihold(inode);
 		error = mnt_want_write(nd.path.mnt);
 		if (error)
 			goto exit2;
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index e257172d438c..0fac7fea18ef 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1580,7 +1580,7 @@ nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
 	d_drop(dentry);
 	error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name);
 	if (error == 0) {
-		atomic_inc(&inode->i_count);
+		ihold(inode);
 		d_add(dentry, inode);
 	}
 	return error;
diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c
index a70e446e1605..ac7b814ce162 100644
--- a/fs/nfs/getroot.c
+++ b/fs/nfs/getroot.c
@@ -54,8 +54,7 @@ static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *i
 			iput(inode);
 			return -ENOMEM;
 		}
-		/* Circumvent igrab(): we know the inode is not being freed */
-		atomic_inc(&inode->i_count);
+		ihold(inode);
 		/*
 		 * Ensure that this dentry is invisible to d_find_alias().
 		 * Otherwise, it may be spliced into the tree by
diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c
index 185d1607cb00..6e9557ecf161 100644
--- a/fs/nilfs2/namei.c
+++ b/fs/nilfs2/namei.c
@@ -207,7 +207,7 @@ static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
 
 	inode->i_ctime = CURRENT_TIME;
 	inode_inc_link_count(inode);
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 
 	err = nilfs_add_nondir(dentry, inode);
 	if (!err)
diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c
index d4dec2d32117..d3fbe5730bfc 100644
--- a/fs/ntfs/super.c
+++ b/fs/ntfs/super.c
@@ -2911,8 +2911,8 @@ static int ntfs_fill_super(struct super_block *sb, void *opt, const int silent)
 		goto unl_upcase_iput_tmp_ino_err_out_now;
 	}
 	if ((sb->s_root = d_alloc_root(vol->root_ino))) {
-		/* We increment i_count simulating an ntfs_iget(). */
-		atomic_inc(&vol->root_ino->i_count);
+		/* We grab a reference, simulating an ntfs_iget(). */
+		ihold(vol->root_ino);
 		ntfs_debug("Exiting, status successful.");
 		/* Release the default upcase if it has no users. */
 		mutex_lock(&ntfs_lock);
diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index e7bde21149ae..ff5744e1e36f 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -742,7 +742,7 @@ static int ocfs2_link(struct dentry *old_dentry,
 		goto out_commit;
 	}
 
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 	dentry->d_op = &ocfs2_dentry_ops;
 	d_instantiate(dentry, inode);
 
diff --git a/fs/reiserfs/namei.c b/fs/reiserfs/namei.c
index ee78d4a0086a..ba5f51ec3458 100644
--- a/fs/reiserfs/namei.c
+++ b/fs/reiserfs/namei.c
@@ -1156,7 +1156,7 @@ static int reiserfs_link(struct dentry *old_dentry, struct inode *dir,
 	inode->i_ctime = CURRENT_TIME_SEC;
 	reiserfs_update_sd(&th, inode);
 
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 	d_instantiate(dentry, inode);
 	retval = journal_end(&th, dir->i_sb, jbegin_count);
 	reiserfs_write_unlock(dir->i_sb);
diff --git a/fs/sysv/namei.c b/fs/sysv/namei.c
index 33e047b59b8d..11e7f7d11cd0 100644
--- a/fs/sysv/namei.c
+++ b/fs/sysv/namei.c
@@ -126,7 +126,7 @@ static int sysv_link(struct dentry * old_dentry, struct inode * dir,
 
 	inode->i_ctime = CURRENT_TIME_SEC;
 	inode_inc_link_count(inode);
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 
 	return add_nondir(dentry, inode);
 }
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 87ebcce72213..14f64b689d7f 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -550,7 +550,7 @@ static int ubifs_link(struct dentry *old_dentry, struct inode *dir,
 
 	lock_2_inodes(dir, inode);
 	inc_nlink(inode);
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 	inode->i_ctime = ubifs_current_time(inode);
 	dir->i_size += sz_change;
 	dir_ui->ui_size = dir->i_size;
diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index bf5fc674193c..6d8dc02baebb 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -1101,7 +1101,7 @@ static int udf_link(struct dentry *old_dentry, struct inode *dir,
 	inc_nlink(inode);
 	inode->i_ctime = current_fs_time(inode->i_sb);
 	mark_inode_dirty(inode);
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 	d_instantiate(dentry, inode);
 	unlock_kernel();
 
diff --git a/fs/ufs/namei.c b/fs/ufs/namei.c
index b056f02b1fb3..12f39b9e4437 100644
--- a/fs/ufs/namei.c
+++ b/fs/ufs/namei.c
@@ -180,7 +180,7 @@ static int ufs_link (struct dentry * old_dentry, struct inode * dir,
 
 	inode->i_ctime = CURRENT_TIME_SEC;
 	inode_inc_link_count(inode);
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 
 	error = ufs_add_nondir(dentry, inode);
 	unlock_kernel();
diff --git a/fs/xfs/linux-2.6/xfs_iops.c b/fs/xfs/linux-2.6/xfs_iops.c
index 71d83c93621c..96107efc0c61 100644
--- a/fs/xfs/linux-2.6/xfs_iops.c
+++ b/fs/xfs/linux-2.6/xfs_iops.c
@@ -317,7 +317,7 @@ xfs_vn_link(
 	if (unlikely(error))
 		return -error;
 
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 	d_instantiate(dentry, inode);
 	return 0;
 }
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index fac52290de90..fb2ca2e4cdc9 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -500,7 +500,7 @@ void		xfs_mark_inode_dirty_sync(xfs_inode_t *);
 #define IHOLD(ip) \
 do { \
 	ASSERT(atomic_read(&VFS_I(ip)->i_count) > 0) ; \
-	atomic_inc(&(VFS_I(ip)->i_count)); \
+	ihold(VFS_I(ip)); \
 	trace_xfs_ihold(ip, _THIS_IP_); \
 } while (0)