Commit acc55e22 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
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[PATCH] md/bitmap: tidy up i_writecount handling in md/bitmap 



md/bitmap modifies i_writecount of a bitmap file to make sure that no-one else
writes to it.  The reverting of the change is sometimes done twice, and there
is one error path where it is omitted.

This patch tidies that up.

Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 0cdd02ca

drivers/md/bitmap.c

+1 −7
Original line number Diff line number Diff line
@@ -625,7 +625,6 @@ static void drain_write_queues(struct bitmap *bitmap) 
static void bitmap_file_put(struct bitmap *bitmap)

{

	struct file *file;

	struct inode *inode;

	unsigned long flags;



	spin_lock_irqsave(&bitmap->lock, flags);
@@ -637,14 +636,9 @@ static void bitmap_file_put(struct bitmap *bitmap) 


	bitmap_file_unmap(bitmap);



	if (file) {

		inode = file->f_mapping->host;

		spin_lock(&inode->i_lock);

		atomic_set(&inode->i_writecount, 1); /* allow writes again */

		spin_unlock(&inode->i_lock);

	if (file)

		fput(file);

}

}





/*

drivers/md/md.c

+30 −19
Original line number Diff line number Diff line
@@ -2877,6 +2877,32 @@ static int restart_array(mddev_t *mddev) 
	return err;

}



/* similar to deny_write_access, but accounts for our holding a reference

 * to the file ourselves */

static int deny_bitmap_write_access(struct file * file)

{

	struct inode *inode = file->f_mapping->host;



	spin_lock(&inode->i_lock);

	if (atomic_read(&inode->i_writecount) > 1) {

		spin_unlock(&inode->i_lock);

		return -ETXTBSY;

	}

	atomic_set(&inode->i_writecount, -1);

	spin_unlock(&inode->i_lock);



	return 0;

}



static void restore_bitmap_write_access(struct file *file)

{

	struct inode *inode = file->f_mapping->host;



	spin_lock(&inode->i_lock);

	atomic_set(&inode->i_writecount, 1);

	spin_unlock(&inode->i_lock);

}



static int do_md_stop(mddev_t * mddev, int ro)

{

	int err = 0;
@@ -2940,7 +2966,7 @@ static int do_md_stop(mddev_t * mddev, int ro) 


		bitmap_destroy(mddev);

		if (mddev->bitmap_file) {

			atomic_set(&mddev->bitmap_file->f_dentry->d_inode->i_writecount, 1);

			restore_bitmap_write_access(mddev->bitmap_file);

			fput(mddev->bitmap_file);

			mddev->bitmap_file = NULL;

		}
@@ -3544,23 +3570,6 @@ static int hot_add_disk(mddev_t * mddev, dev_t dev) 
	return err;

}



/* similar to deny_write_access, but accounts for our holding a reference

 * to the file ourselves */

static int deny_bitmap_write_access(struct file * file)

{

	struct inode *inode = file->f_mapping->host;



	spin_lock(&inode->i_lock);

	if (atomic_read(&inode->i_writecount) > 1) {

		spin_unlock(&inode->i_lock);

		return -ETXTBSY;

	}

	atomic_set(&inode->i_writecount, -1);

	spin_unlock(&inode->i_lock);



	return 0;

}



static int set_bitmap_file(mddev_t *mddev, int fd)

{

	int err;
@@ -3608,8 +3617,10 @@ static int set_bitmap_file(mddev_t *mddev, int fd) 
		mddev->pers->quiesce(mddev, 0);

	}

	if (fd < 0) {

		if (mddev->bitmap_file)

		if (mddev->bitmap_file) {

			restore_bitmap_write_access(mddev->bitmap_file);

			fput(mddev->bitmap_file);

		}

		mddev->bitmap_file = NULL;

	}