[PATCH 007 of 8] md/bitmap: Tidy up i_writecount handling in md/bitmap

NeilBrown
2006-05-12T06:09:09Z

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: Neil Brown <neilb@suse.de>

### Diffstat output
./drivers/md/bitmap.c | 8 +-------
./drivers/md/md.c | 49 ++++++++++++++++++++++++++++++-------------------
2 files changed, 31 insertions(+), 26 deletions(-)

diff ./drivers/md/bitmap.c~current~ ./drivers/md/bitmap.c
--- ./drivers/md/bitmap.c~current~ 2006-05-12 15:59:53.000000000 +1000
+++ ./drivers/md/bitmap.c 2006-05-12 16:00:03.000000000 +1000
@@ -625,7 +625,6 @@ static void drain_write_queues(struct bi
static void bitmap_file_put(struct bitmap *bitmap)
{
struct file *file;
- struct inode *inode;
unsigned long flags;

spin_lock_irqsave(&bitmap->lock, flags);
@@ -637,13 +636,8 @@ static void bitmap_file_put(struct bitma

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);
- }
}

diff ./drivers/md/md.c~current~ ./drivers/md/md.c
--- ./drivers/md/md.c~current~ 2006-05-12 15:54:48.000000000 +1000
+++ ./drivers/md/md.c 2006-05-12 16:00:03.000000000 +1000
@@ -2864,6 +2864,32 @@ out:
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;
@@ -2927,7 +2953,7 @@ static int do_md_stop(mddev_t * mddev, i

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;
}
@@ -3531,23 +3557,6 @@ abort_export:
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;
@@ -3595,8 +3604,10 @@ static int set_bitmap_file(mddev_t *mdde
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;
}