diff options
author | Christoph Hellwig <hch@lst.de> | 2020-11-23 15:38:40 +0300 |
---|---|---|
committer | Jens Axboe <axboe@kernel.dk> | 2020-12-02 00:53:39 +0300 |
commit | 4e7b5671c6a883d94b5428e1a9c141bbd56cb2a6 (patch) | |
tree | 862980514dedf92e87aa3ec651f5be306f207390 /fs/block_dev.c | |
parent | 7918f0f6fdafa1e52c2d77c537cb55ef25fb69a3 (diff) | |
download | linux-4e7b5671c6a883d94b5428e1a9c141bbd56cb2a6.tar.xz |
block: remove i_bdev
Switch the block device lookup interfaces to directly work with a dev_t
so that struct block_device references are only acquired by the
blkdev_get variants (and the blk-cgroup special case). This means that
we now don't need an extra reference in the inode and can generally
simplify handling of struct block_device to keep the lookups contained
in the core block layer code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Coly Li <colyli@suse.de> [bcache]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/block_dev.c')
-rw-r--r-- | fs/block_dev.c | 196 |
1 files changed, 49 insertions, 147 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 2b8c0586314f..6d6e4d50834c 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -883,7 +883,6 @@ static struct block_device *bdget(dev_t dev) bdev->bd_dev = dev; inode->i_mode = S_IFBLK; inode->i_rdev = dev; - inode->i_bdev = bdev; inode->i_data.a_ops = &def_blk_aops; mapping_set_gfp_mask(&inode->i_data, GFP_USER); unlock_new_inode(inode); @@ -928,67 +927,8 @@ void bdput(struct block_device *bdev) { iput(bdev->bd_inode); } - EXPORT_SYMBOL(bdput); -static struct block_device *bd_acquire(struct inode *inode) -{ - struct block_device *bdev; - - spin_lock(&bdev_lock); - bdev = inode->i_bdev; - if (bdev && !inode_unhashed(bdev->bd_inode)) { - bdgrab(bdev); - spin_unlock(&bdev_lock); - return bdev; - } - spin_unlock(&bdev_lock); - - /* - * i_bdev references block device inode that was already shut down - * (corresponding device got removed). Remove the reference and look - * up block device inode again just in case new device got - * reestablished under the same device number. - */ - if (bdev) - bd_forget(inode); - - bdev = bdget(inode->i_rdev); - if (bdev) { - spin_lock(&bdev_lock); - if (!inode->i_bdev) { - /* - * 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(). - */ - bdgrab(bdev); - inode->i_bdev = bdev; - inode->i_mapping = bdev->bd_inode->i_mapping; - } - spin_unlock(&bdev_lock); - } - return bdev; -} - -/* Call when you free inode */ - -void bd_forget(struct inode *inode) -{ - struct block_device *bdev = NULL; - - spin_lock(&bdev_lock); - if (!sb_is_blkdev_sb(inode->i_sb)) - bdev = inode->i_bdev; - inode->i_bdev = NULL; - inode->i_mapping = &inode->i_data; - spin_unlock(&bdev_lock); - - if (bdev) - bdput(bdev); -} - /** * bd_may_claim - test whether a block device can be claimed * @bdev: block device of interest @@ -1497,38 +1437,45 @@ static int __blkdev_get(struct block_device *bdev, struct gendisk *disk, } /** - * blkdev_get - open a block device - * @bdev: block_device to open + * blkdev_get_by_dev - open a block device by device number + * @dev: device number of block device to open * @mode: FMODE_* mask * @holder: exclusive holder identifier * - * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is - * open with exclusive access. Specifying %FMODE_EXCL with %NULL - * @holder is invalid. Exclusive opens may nest for the same @holder. + * Open the block device described by device number @dev. If @mode includes + * %FMODE_EXCL, the block device is opened with exclusive access. Specifying + * %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may nest for + * the same @holder. * - * On success, the reference count of @bdev is unchanged. On failure, - * @bdev is put. + * Use this interface ONLY if you really do not have anything better - i.e. when + * you are behind a truly sucky interface and all you are given is a device + * number. Everything else should use blkdev_get_by_path(). * * CONTEXT: * Might sleep. * * RETURNS: - * 0 on success, -errno on failure. + * Reference to the block_device on success, ERR_PTR(-errno) on failure. */ -static int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) +struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) { struct block_device *claiming; bool unblock_events = true; + struct block_device *bdev; struct gendisk *disk; int partno; int ret; ret = devcgroup_check_permission(DEVCG_DEV_BLOCK, - imajor(bdev->bd_inode), iminor(bdev->bd_inode), + MAJOR(dev), MINOR(dev), ((mode & FMODE_READ) ? DEVCG_ACC_READ : 0) | ((mode & FMODE_WRITE) ? DEVCG_ACC_WRITE : 0)); if (ret) - goto bdput; + return ERR_PTR(ret); + + bdev = bdget(dev); + if (!bdev) + return ERR_PTR(-ENOMEM); /* * If we lost a race with 'disk' being deleted, try again. See md.c. @@ -1589,10 +1536,13 @@ put_disk: if (ret == -ERESTARTSYS) goto retry; bdput: - if (ret) + if (ret) { bdput(bdev); - return ret; + return ERR_PTR(ret); + } + return bdev; } +EXPORT_SYMBOL(blkdev_get_by_dev); /** * blkdev_get_by_path - open a block device by name @@ -1600,32 +1550,30 @@ bdput: * @mode: FMODE_* mask * @holder: exclusive holder identifier * - * Open the blockdevice described by the device file at @path. @mode - * and @holder are identical to blkdev_get(). - * - * On success, the returned block_device has reference count of one. + * Open the block device described by the device file at @path. If @mode + * includes %FMODE_EXCL, the block device is opened with exclusive access. + * Specifying %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may + * nest for the same @holder. * * CONTEXT: * Might sleep. * * RETURNS: - * Pointer to block_device on success, ERR_PTR(-errno) on failure. + * Reference to the block_device on success, ERR_PTR(-errno) on failure. */ struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, void *holder) { struct block_device *bdev; - int err; - - bdev = lookup_bdev(path); - if (IS_ERR(bdev)) - return bdev; + dev_t dev; + int error; - err = blkdev_get(bdev, mode, holder); - if (err) - return ERR_PTR(err); + error = lookup_bdev(path, &dev); + if (error) + return ERR_PTR(error); - if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) { + bdev = blkdev_get_by_dev(dev, mode, holder); + if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) { blkdev_put(bdev, mode); return ERR_PTR(-EACCES); } @@ -1634,45 +1582,6 @@ struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, } EXPORT_SYMBOL(blkdev_get_by_path); -/** - * blkdev_get_by_dev - open a block device by device number - * @dev: device number of block device to open - * @mode: FMODE_* mask - * @holder: exclusive holder identifier - * - * Open the blockdevice described by device number @dev. @mode and - * @holder are identical to blkdev_get(). - * - * Use it ONLY if you really do not have anything better - i.e. when - * you are behind a truly sucky interface and all you are given is a - * device number. _Never_ to be used for internal purposes. If you - * ever need it - reconsider your API. - * - * On success, the returned block_device has reference count of one. - * - * CONTEXT: - * Might sleep. - * - * RETURNS: - * Pointer to block_device on success, ERR_PTR(-errno) on failure. - */ -struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) -{ - struct block_device *bdev; - int err; - - bdev = bdget(dev); - if (!bdev) - return ERR_PTR(-ENOMEM); - - err = blkdev_get(bdev, mode, holder); - if (err) - return ERR_PTR(err); - - return bdev; -} -EXPORT_SYMBOL(blkdev_get_by_dev); - static int blkdev_open(struct inode * inode, struct file * filp) { struct block_device *bdev; @@ -1694,14 +1603,12 @@ static int blkdev_open(struct inode * inode, struct file * filp) if ((filp->f_flags & O_ACCMODE) == 3) filp->f_mode |= FMODE_WRITE_IOCTL; - bdev = bd_acquire(inode); - if (bdev == NULL) - return -ENOMEM; - + bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp); + if (IS_ERR(bdev)) + return PTR_ERR(bdev); filp->f_mapping = bdev->bd_inode->i_mapping; filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping); - - return blkdev_get(bdev, filp->f_mode, filp); + return 0; } static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) @@ -2010,37 +1917,32 @@ const struct file_operations def_blk_fops = { * namespace if possible and return it. Return ERR_PTR(error) * otherwise. */ -struct block_device *lookup_bdev(const char *pathname) +int lookup_bdev(const char *pathname, dev_t *dev) { - struct block_device *bdev; struct inode *inode; struct path path; int error; if (!pathname || !*pathname) - return ERR_PTR(-EINVAL); + return -EINVAL; error = kern_path(pathname, LOOKUP_FOLLOW, &path); if (error) - return ERR_PTR(error); + return error; inode = d_backing_inode(path.dentry); error = -ENOTBLK; if (!S_ISBLK(inode->i_mode)) - goto fail; + goto out_path_put; error = -EACCES; if (!may_open_dev(&path)) - goto fail; - error = -ENOMEM; - bdev = bd_acquire(inode); - if (!bdev) - goto fail; -out: + goto out_path_put; + + *dev = inode->i_rdev; + error = 0; +out_path_put: path_put(&path); - return bdev; -fail: - bdev = ERR_PTR(error); - goto out; + return error; } EXPORT_SYMBOL(lookup_bdev); |