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md: move GET_BITMAP_FILE ioctl out from mddev_lock.

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It makes more sense to report bitmap_info->file, rather than
bitmap->file (the later is only available once the array is
active).

With that change, use mddev->lock to protect bitmap_info being
set to NULL, and we can call get_bitmap_file() without taking
the mutex.

Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2014-12-15 12:57:00 +11:00
parent 1e594bb24d
commit 4af1a04176
2 changed files with 35 additions and 28 deletions
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62
drivers/md/md.c
View File

@ -5292,8 +5292,11 @@ static int do_md_stop(struct mddev *mddev, int mode,
bitmap_destroy(mddev);
if (mddev->bitmap_info.file) {
fput(mddev->bitmap_info.file);
struct file *f = mddev->bitmap_info.file;
spin_lock(&mddev->lock);
mddev->bitmap_info.file = NULL;
spin_unlock(&mddev->lock);
fput(f);
}
mddev->bitmap_info.offset = 0;
@ -5503,32 +5506,30 @@ static int get_bitmap_file(struct mddev *mddev, void __user * arg)
{
mdu_bitmap_file_t *file = NULL; /* too big for stack allocation */
char *ptr;
int err = -ENOMEM;
int err;
file = kmalloc(sizeof(*file), GFP_NOIO);
if (!file)
goto out;
return -ENOMEM;
/* bitmap disabled, zero the first byte and copy out */
if (!mddev->bitmap || !mddev->bitmap->storage.file) {
file->pathname[0] = '\0';
goto copy_out;
}
ptr = d_path(&mddev->bitmap->storage.file->f_path,
file->pathname, sizeof(file->pathname));
if (IS_ERR(ptr))
goto out;
memmove(file->pathname, ptr,
sizeof(file->pathname)-(ptr-file->pathname));
copy_out:
err = 0;
if (copy_to_user(arg, file, sizeof(*file)))
spin_lock(&mddev->lock);
/* bitmap disabled, zero the first byte and copy out */
if (!mddev->bitmap_info.file)
file->pathname[0] = '\0';
else if ((ptr = d_path(&mddev->bitmap_info.file->f_path,
file->pathname, sizeof(file->pathname))),
IS_ERR(ptr))
err = PTR_ERR(ptr);
else
memmove(file->pathname, ptr,
sizeof(file->pathname)-(ptr-file->pathname));
spin_unlock(&mddev->lock);
if (err == 0 &&
copy_to_user(arg, file, sizeof(*file)))
err = -EFAULT;
out:
kfree(file);
return err;
}
@ -5900,9 +5901,13 @@ static int set_bitmap_file(struct mddev *mddev, int fd)
mddev->pers->quiesce(mddev, 0);
}
if (fd < 0) {
if (mddev->bitmap_info.file)
fput(mddev->bitmap_info.file);
mddev->bitmap_info.file = NULL;
struct file *f = mddev->bitmap_info.file;
if (f) {
spin_lock(&mddev->lock);
mddev->bitmap_info.file = NULL;
spin_unlock(&mddev->lock);
fput(f);
}
}
return err;
@ -6315,6 +6320,11 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
case SET_DISK_FAULTY:
err = set_disk_faulty(mddev, new_decode_dev(arg));
goto out;
case GET_BITMAP_FILE:
err = get_bitmap_file(mddev, argp);
goto out;
}
if (cmd == ADD_NEW_DISK)
@ -6406,10 +6416,6 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
* Commands even a read-only array can execute:
*/
switch (cmd) {
case GET_BITMAP_FILE:
err = get_bitmap_file(mddev, argp);
goto unlock;
case RESTART_ARRAY_RW:
err = restart_array(mddev);
goto unlock;

1
drivers/md/md.h
View File

@ -393,6 +393,7 @@ struct mddev {
* in_sync - and related safemode and MD_CHANGE changes
* pers (also protected by reconfig_mutex and pending IO).
* clearing ->bitmap
* clearing ->bitmap_info.file
*/
spinlock_t lock;
wait_queue_head_t sb_wait; /* for waiting on superblock updates */