From e09b457bdb7e8d23fc54dcef0930ac697d8de895 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sat, 13 Nov 2010 11:55:17 +0100 Subject: block: simplify holder symlink handling Code to manage symlinks in /sys/block/*/{holders|slaves} are overly complex with multiple holder considerations, redundant extra references to all involved kobjects, unused generic kobject holder support and unnecessary mixup with bd_claim/release functionalities. Strip it down to what's necessary (single gendisk holder) and make it use a separate interface. This is a step for cleaning up bd_claim/release. This patch makes dm-table slightly more complex but it will be simplified again with further changes. Signed-off-by: Tejun Heo Acked-by: Neil Brown Acked-by: Mike Snitzer Cc: dm-devel@redhat.com --- fs/block_dev.c | 322 ++++++++------------------------------------------------- 1 file changed, 44 insertions(+), 278 deletions(-) (limited to 'fs/block_dev.c') diff --git a/fs/block_dev.c b/fs/block_dev.c index 06e8ff12b97c..9329068684d2 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -426,9 +426,6 @@ static void init_once(void *foo) mutex_init(&bdev->bd_mutex); INIT_LIST_HEAD(&bdev->bd_inodes); INIT_LIST_HEAD(&bdev->bd_list); -#ifdef CONFIG_SYSFS - INIT_LIST_HEAD(&bdev->bd_holder_list); -#endif inode_init_once(&ei->vfs_inode); /* Initialize mutex for freeze. */ mutex_init(&bdev->bd_fsfreeze_mutex); @@ -881,314 +878,83 @@ void bd_release(struct block_device *bdev) EXPORT_SYMBOL(bd_release); #ifdef CONFIG_SYSFS -/* - * Functions for bd_claim_by_kobject / bd_release_from_kobject - * - * If a kobject is passed to bd_claim_by_kobject() - * and the kobject has a parent directory, - * following symlinks are created: - * o from the kobject to the claimed bdev - * o from "holders" directory of the bdev to the parent of the kobject - * bd_release_from_kobject() removes these symlinks. - * - * Example: - * If /dev/dm-0 maps to /dev/sda, kobject corresponding to - * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then: - * /sys/block/dm-0/slaves/sda --> /sys/block/sda - * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 - */ - static int add_symlink(struct kobject *from, struct kobject *to) { - if (!from || !to) - return 0; return sysfs_create_link(from, to, kobject_name(to)); } static void del_symlink(struct kobject *from, struct kobject *to) { - if (!from || !to) - return; sysfs_remove_link(from, kobject_name(to)); } -/* - * 'struct bd_holder' contains pointers to kobjects symlinked by - * bd_claim_by_kobject. - * It's connected to bd_holder_list which is protected by bdev->bd_sem. - */ -struct bd_holder { - struct list_head list; /* chain of holders of the bdev */ - int count; /* references from the holder */ - struct kobject *sdir; /* holder object, e.g. "/block/dm-0/slaves" */ - struct kobject *hdev; /* e.g. "/block/dm-0" */ - struct kobject *hdir; /* e.g. "/block/sda/holders" */ - struct kobject *sdev; /* e.g. "/block/sda" */ -}; - -/* - * Get references of related kobjects at once. - * Returns 1 on success. 0 on failure. - * - * Should call bd_holder_release_dirs() after successful use. - */ -static int bd_holder_grab_dirs(struct block_device *bdev, - struct bd_holder *bo) -{ - if (!bdev || !bo) - return 0; - - bo->sdir = kobject_get(bo->sdir); - if (!bo->sdir) - return 0; - - bo->hdev = kobject_get(bo->sdir->parent); - if (!bo->hdev) - goto fail_put_sdir; - - bo->sdev = kobject_get(&part_to_dev(bdev->bd_part)->kobj); - if (!bo->sdev) - goto fail_put_hdev; - - bo->hdir = kobject_get(bdev->bd_part->holder_dir); - if (!bo->hdir) - goto fail_put_sdev; - - return 1; - -fail_put_sdev: - kobject_put(bo->sdev); -fail_put_hdev: - kobject_put(bo->hdev); -fail_put_sdir: - kobject_put(bo->sdir); - - return 0; -} - -/* Put references of related kobjects at once. */ -static void bd_holder_release_dirs(struct bd_holder *bo) -{ - kobject_put(bo->hdir); - kobject_put(bo->sdev); - kobject_put(bo->hdev); - kobject_put(bo->sdir); -} - -static struct bd_holder *alloc_bd_holder(struct kobject *kobj) -{ - struct bd_holder *bo; - - bo = kzalloc(sizeof(*bo), GFP_KERNEL); - if (!bo) - return NULL; - - bo->count = 1; - bo->sdir = kobj; - - return bo; -} - -static void free_bd_holder(struct bd_holder *bo) -{ - kfree(bo); -} - /** - * find_bd_holder - find matching struct bd_holder from the block device + * bd_link_disk_holder - create symlinks between holding disk and slave bdev + * @bdev: the claimed slave bdev + * @disk: the holding disk * - * @bdev: struct block device to be searched - * @bo: target struct bd_holder + * This functions creates the following sysfs symlinks. * - * Returns matching entry with @bo in @bdev->bd_holder_list. - * If found, increment the reference count and return the pointer. - * If not found, returns NULL. - */ -static struct bd_holder *find_bd_holder(struct block_device *bdev, - struct bd_holder *bo) -{ - struct bd_holder *tmp; - - list_for_each_entry(tmp, &bdev->bd_holder_list, list) - if (tmp->sdir == bo->sdir) { - tmp->count++; - return tmp; - } - - return NULL; -} - -/** - * add_bd_holder - create sysfs symlinks for bd_claim() relationship + * - from "slaves" directory of the holder @disk to the claimed @bdev + * - from "holders" directory of the @bdev to the holder @disk * - * @bdev: block device to be bd_claimed - * @bo: preallocated and initialized by alloc_bd_holder() + * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is + * passed to bd_link_disk_holder(), then: * - * Add @bo to @bdev->bd_holder_list, create symlinks. + * /sys/block/dm-0/slaves/sda --> /sys/block/sda + * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 * - * Returns 0 if symlinks are created. - * Returns -ve if something fails. - */ -static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo) -{ - int err; - - if (!bo) - return -EINVAL; - - if (!bd_holder_grab_dirs(bdev, bo)) - return -EBUSY; - - err = add_symlink(bo->sdir, bo->sdev); - if (err) - return err; - - err = add_symlink(bo->hdir, bo->hdev); - if (err) { - del_symlink(bo->sdir, bo->sdev); - return err; - } - - list_add_tail(&bo->list, &bdev->bd_holder_list); - return 0; -} - -/** - * del_bd_holder - delete sysfs symlinks for bd_claim() relationship - * - * @bdev: block device to be bd_claimed - * @kobj: holder's kobject - * - * If there is matching entry with @kobj in @bdev->bd_holder_list - * and no other bd_claim() from the same kobject, - * remove the struct bd_holder from the list, delete symlinks for it. - * - * Returns a pointer to the struct bd_holder when it's removed from the list - * and ready to be freed. - * Returns NULL if matching claim isn't found or there is other bd_claim() - * by the same kobject. - */ -static struct bd_holder *del_bd_holder(struct block_device *bdev, - struct kobject *kobj) -{ - struct bd_holder *bo; - - list_for_each_entry(bo, &bdev->bd_holder_list, list) { - if (bo->sdir == kobj) { - bo->count--; - BUG_ON(bo->count < 0); - if (!bo->count) { - list_del(&bo->list); - del_symlink(bo->sdir, bo->sdev); - del_symlink(bo->hdir, bo->hdev); - bd_holder_release_dirs(bo); - return bo; - } - break; - } - } - - return NULL; -} - -/** - * bd_claim_by_kobject - bd_claim() with additional kobject signature - * - * @bdev: block device to be claimed - * @holder: holder's signature - * @kobj: holder's kobject + * The caller must have claimed @bdev before calling this function and + * ensure that both @bdev and @disk are valid during the creation and + * lifetime of these symlinks. * - * Do bd_claim() and if it succeeds, create sysfs symlinks between - * the bdev and the holder's kobject. - * Use bd_release_from_kobject() when relesing the claimed bdev. + * CONTEXT: + * Might sleep. * - * Returns 0 on success. (same as bd_claim()) - * Returns errno on failure. + * RETURNS: + * 0 on success, -errno on failure. */ -static int bd_claim_by_kobject(struct block_device *bdev, void *holder, - struct kobject *kobj) +int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) { - int err; - struct bd_holder *bo, *found; - - if (!kobj) - return -EINVAL; - - bo = alloc_bd_holder(kobj); - if (!bo) - return -ENOMEM; + int ret = 0; mutex_lock(&bdev->bd_mutex); - err = bd_claim(bdev, holder); - if (err) - goto fail; + WARN_ON_ONCE(!bdev->bd_holder || bdev->bd_holder_disk); - found = find_bd_holder(bdev, bo); - if (found) - goto fail; + /* FIXME: remove the following once add_disk() handles errors */ + if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir)) + goto out_unlock; - err = add_bd_holder(bdev, bo); - if (err) - bd_release(bdev); - else - bo = NULL; -fail: - mutex_unlock(&bdev->bd_mutex); - free_bd_holder(bo); - return err; -} + ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); + if (ret) + goto out_unlock; -/** - * bd_release_from_kobject - bd_release() with additional kobject signature - * - * @bdev: block device to be released - * @kobj: holder's kobject - * - * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject(). - */ -static void bd_release_from_kobject(struct block_device *bdev, - struct kobject *kobj) -{ - if (!kobj) - return; + ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj); + if (ret) { + del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); + goto out_unlock; + } - mutex_lock(&bdev->bd_mutex); - bd_release(bdev); - free_bd_holder(del_bd_holder(bdev, kobj)); + bdev->bd_holder_disk = disk; +out_unlock: mutex_unlock(&bdev->bd_mutex); + return ret; } +EXPORT_SYMBOL_GPL(bd_link_disk_holder); -/** - * bd_claim_by_disk - wrapper function for bd_claim_by_kobject() - * - * @bdev: block device to be claimed - * @holder: holder's signature - * @disk: holder's gendisk - * - * Call bd_claim_by_kobject() with getting @disk->slave_dir. - */ -int bd_claim_by_disk(struct block_device *bdev, void *holder, - struct gendisk *disk) +void bd_unlink_disk_holder(struct block_device *bdev) { - return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir)); -} -EXPORT_SYMBOL_GPL(bd_claim_by_disk); + struct gendisk *disk = bdev->bd_holder_disk; -/** - * bd_release_from_disk - wrapper function for bd_release_from_kobject() - * - * @bdev: block device to be claimed - * @disk: holder's gendisk - * - * Call bd_release_from_kobject() and put @disk->slave_dir. - */ -void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk) -{ - bd_release_from_kobject(bdev, disk->slave_dir); - kobject_put(disk->slave_dir); + bdev->bd_holder_disk = NULL; + if (!disk) + return; + + del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); + del_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj); } -EXPORT_SYMBOL_GPL(bd_release_from_disk); +EXPORT_SYMBOL_GPL(bd_unlink_disk_holder); #endif /* -- cgit v1.2.3 From e525fd89d380c4a94c0d63913a1dd1a593ed25e7 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sat, 13 Nov 2010 11:55:17 +0100 Subject: block: make blkdev_get/put() handle exclusive access Over time, block layer has accumulated a set of APIs dealing with bdev open, close, claim and release. * blkdev_get/put() are the primary open and close functions. * bd_claim/release() deal with exclusive open. * open/close_bdev_exclusive() are combination of open and claim and the other way around, respectively. * bd_link/unlink_disk_holder() to create and remove holder/slave symlinks. * open_by_devnum() wraps bdget() + blkdev_get(). The interface is a bit confusing and the decoupling of open and claim makes it impossible to properly guarantee exclusive access as in-kernel open + claim sequence can disturb the existing exclusive open even before the block layer knows the current open if for another exclusive access. Reorganize the interface such that, * blkdev_get() is extended to include exclusive access management. @holder argument is added and, if is @FMODE_EXCL specified, it will gain exclusive access atomically w.r.t. other exclusive accesses. * blkdev_put() is similarly extended. It now takes @mode argument and if @FMODE_EXCL is set, it releases an exclusive access. Also, when the last exclusive claim is released, the holder/slave symlinks are removed automatically. * bd_claim/release() and close_bdev_exclusive() are no longer necessary and either made static or removed. * bd_link_disk_holder() remains the same but bd_unlink_disk_holder() is no longer necessary and removed. * open_bdev_exclusive() becomes a simple wrapper around lookup_bdev() and blkdev_get(). It also has an unexpected extra bdev_read_only() test which probably should be moved into blkdev_get(). * open_by_devnum() is modified to take @holder argument and pass it to blkdev_get(). Most of bdev open/close operations are unified into blkdev_get/put() and most exclusive accesses are tested atomically at the open time (as it should). This cleans up code and removes some, both valid and invalid, but unnecessary all the same, corner cases. open_bdev_exclusive() and open_by_devnum() can use further cleanup - rename to blkdev_get_by_path() and blkdev_get_by_devt() and drop special features. Well, let's leave them for another day. Most conversions are straight-forward. drbd conversion is a bit more involved as there was some reordering, but the logic should stay the same. Signed-off-by: Tejun Heo Acked-by: Neil Brown Acked-by: Ryusuke Konishi Acked-by: Mike Snitzer Acked-by: Philipp Reisner Cc: Peter Osterlund Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Jan Kara Cc: Andrew Morton Cc: Andreas Dilger Cc: "Theodore Ts'o" Cc: Mark Fasheh Cc: Joel Becker Cc: Alex Elder Cc: Christoph Hellwig Cc: dm-devel@redhat.com Cc: drbd-dev@lists.linbit.com Cc: Leo Chen Cc: Scott Branden Cc: Chris Mason Cc: Steven Whitehouse Cc: Dave Kleikamp Cc: Joern Engel Cc: reiserfs-devel@vger.kernel.org Cc: Alexander Viro --- block/ioctl.c | 5 +- drivers/block/drbd/drbd_int.h | 2 - drivers/block/drbd/drbd_main.c | 7 +- drivers/block/drbd/drbd_nl.c | 103 ++++++++++----------------- drivers/block/pktcdvd.c | 22 +++--- drivers/char/raw.c | 14 ++-- drivers/md/dm-table.c | 15 +--- drivers/md/md.c | 14 +--- drivers/mtd/devices/block2mtd.c | 17 ++--- drivers/s390/block/dasd_genhd.c | 2 +- fs/block_dev.c | 149 ++++++++++++++-------------------------- fs/btrfs/volumes.c | 14 ++-- fs/ext3/super.c | 12 +--- fs/ext4/super.c | 12 +--- fs/gfs2/ops_fstype.c | 4 +- fs/jfs/jfs_logmgr.c | 17 ++--- fs/logfs/dev_bdev.c | 4 +- fs/nilfs2/super.c | 4 +- fs/ocfs2/cluster/heartbeat.c | 2 +- fs/partitions/check.c | 2 +- fs/reiserfs/journal.c | 17 ++--- fs/super.c | 14 ++-- fs/xfs/linux-2.6/xfs_super.c | 2 +- include/linux/fs.h | 14 ++-- kernel/power/swap.c | 5 +- mm/swapfile.c | 7 +- 26 files changed, 162 insertions(+), 318 deletions(-) (limited to 'fs/block_dev.c') diff --git a/block/ioctl.c b/block/ioctl.c index d724ceb1d465..cc46d499fd27 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -294,11 +294,12 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd, return -EINVAL; if (get_user(n, (int __user *) arg)) return -EFAULT; - if (!(mode & FMODE_EXCL) && bd_claim(bdev, &bdev) < 0) + if (!(mode & FMODE_EXCL) && + blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0) return -EBUSY; ret = set_blocksize(bdev, n); if (!(mode & FMODE_EXCL)) - bd_release(bdev); + blkdev_put(bdev, mode | FMODE_EXCL); return ret; case BLKPG: ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg); diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h index 9bdcf4393c0a..0590b9f67ec6 100644 --- a/drivers/block/drbd/drbd_int.h +++ b/drivers/block/drbd/drbd_int.h @@ -923,8 +923,6 @@ struct drbd_md { struct drbd_backing_dev { struct block_device *backing_bdev; struct block_device *md_bdev; - struct file *lo_file; - struct file *md_file; struct drbd_md md; struct disk_conf dc; /* The user provided config... */ sector_t known_size; /* last known size of that backing device */ diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index 25c7a73c5062..7ec1a82064a9 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -3361,11 +3361,8 @@ void drbd_free_bc(struct drbd_backing_dev *ldev) if (ldev == NULL) return; - bd_release(ldev->backing_bdev); - bd_release(ldev->md_bdev); - - fput(ldev->lo_file); - fput(ldev->md_file); + blkdev_put(ldev->backing_bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); + blkdev_put(ldev->md_bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); kfree(ldev); } diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index 87925e97e613..fd0346090289 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -855,7 +855,7 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp sector_t max_possible_sectors; sector_t min_md_device_sectors; struct drbd_backing_dev *nbc = NULL; /* new_backing_conf */ - struct inode *inode, *inode2; + struct block_device *bdev; struct lru_cache *resync_lru = NULL; union drbd_state ns, os; unsigned int max_seg_s; @@ -902,46 +902,40 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp } } - nbc->lo_file = filp_open(nbc->dc.backing_dev, O_RDWR, 0); - if (IS_ERR(nbc->lo_file)) { + bdev = open_bdev_exclusive(nbc->dc.backing_dev, + FMODE_READ | FMODE_WRITE, mdev); + if (IS_ERR(bdev)) { dev_err(DEV, "open(\"%s\") failed with %ld\n", nbc->dc.backing_dev, - PTR_ERR(nbc->lo_file)); - nbc->lo_file = NULL; + PTR_ERR(bdev)); retcode = ERR_OPEN_DISK; goto fail; } + nbc->backing_bdev = bdev; - inode = nbc->lo_file->f_dentry->d_inode; - - if (!S_ISBLK(inode->i_mode)) { - retcode = ERR_DISK_NOT_BDEV; - goto fail; - } - - nbc->md_file = filp_open(nbc->dc.meta_dev, O_RDWR, 0); - if (IS_ERR(nbc->md_file)) { + /* + * meta_dev_idx >= 0: external fixed size, possibly multiple + * drbd sharing one meta device. TODO in that case, paranoia + * check that [md_bdev, meta_dev_idx] is not yet used by some + * other drbd minor! (if you use drbd.conf + drbdadm, that + * should check it for you already; but if you don't, or + * someone fooled it, we need to double check here) + */ + bdev = open_bdev_exclusive(nbc->dc.meta_dev, + FMODE_READ | FMODE_WRITE, + (nbc->dc.meta_dev_idx < 0) ? + (void *)mdev : (void *)drbd_m_holder); + if (IS_ERR(bdev)) { dev_err(DEV, "open(\"%s\") failed with %ld\n", nbc->dc.meta_dev, - PTR_ERR(nbc->md_file)); - nbc->md_file = NULL; + PTR_ERR(bdev)); retcode = ERR_OPEN_MD_DISK; goto fail; } + nbc->md_bdev = bdev; - inode2 = nbc->md_file->f_dentry->d_inode; - - if (!S_ISBLK(inode2->i_mode)) { - retcode = ERR_MD_NOT_BDEV; - goto fail; - } - - nbc->backing_bdev = inode->i_bdev; - if (bd_claim(nbc->backing_bdev, mdev)) { - printk(KERN_ERR "drbd: bd_claim(%p,%p); failed [%p;%p;%u]\n", - nbc->backing_bdev, mdev, - nbc->backing_bdev->bd_holder, - nbc->backing_bdev->bd_contains->bd_holder, - nbc->backing_bdev->bd_holders); - retcode = ERR_BDCLAIM_DISK; + if ((nbc->backing_bdev == nbc->md_bdev) != + (nbc->dc.meta_dev_idx == DRBD_MD_INDEX_INTERNAL || + nbc->dc.meta_dev_idx == DRBD_MD_INDEX_FLEX_INT)) { + retcode = ERR_MD_IDX_INVALID; goto fail; } @@ -950,28 +944,7 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp offsetof(struct bm_extent, lce)); if (!resync_lru) { retcode = ERR_NOMEM; - goto release_bdev_fail; - } - - /* meta_dev_idx >= 0: external fixed size, - * possibly multiple drbd sharing one meta device. - * TODO in that case, paranoia check that [md_bdev, meta_dev_idx] is - * not yet used by some other drbd minor! - * (if you use drbd.conf + drbdadm, - * that should check it for you already; but if you don't, or someone - * fooled it, we need to double check here) */ - nbc->md_bdev = inode2->i_bdev; - if (bd_claim(nbc->md_bdev, (nbc->dc.meta_dev_idx < 0) ? (void *)mdev - : (void *) drbd_m_holder)) { - retcode = ERR_BDCLAIM_MD_DISK; - goto release_bdev_fail; - } - - if ((nbc->backing_bdev == nbc->md_bdev) != - (nbc->dc.meta_dev_idx == DRBD_MD_INDEX_INTERNAL || - nbc->dc.meta_dev_idx == DRBD_MD_INDEX_FLEX_INT)) { - retcode = ERR_MD_IDX_INVALID; - goto release_bdev2_fail; + goto fail; } /* RT - for drbd_get_max_capacity() DRBD_MD_INDEX_FLEX_INT */ @@ -982,7 +955,7 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp (unsigned long long) drbd_get_max_capacity(nbc), (unsigned long long) nbc->dc.disk_size); retcode = ERR_DISK_TO_SMALL; - goto release_bdev2_fail; + goto fail; } if (nbc->dc.meta_dev_idx < 0) { @@ -999,7 +972,7 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp dev_warn(DEV, "refusing attach: md-device too small, " "at least %llu sectors needed for this meta-disk type\n", (unsigned long long) min_md_device_sectors); - goto release_bdev2_fail; + goto fail; } /* Make sure the new disk is big enough @@ -1007,7 +980,7 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp if (drbd_get_max_capacity(nbc) < drbd_get_capacity(mdev->this_bdev)) { retcode = ERR_DISK_TO_SMALL; - goto release_bdev2_fail; + goto fail; } nbc->known_size = drbd_get_capacity(nbc->backing_bdev); @@ -1030,7 +1003,7 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp retcode = _drbd_request_state(mdev, NS(disk, D_ATTACHING), CS_VERBOSE); drbd_resume_io(mdev); if (retcode < SS_SUCCESS) - goto release_bdev2_fail; + goto fail; if (!get_ldev_if_state(mdev, D_ATTACHING)) goto force_diskless; @@ -1264,18 +1237,14 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp force_diskless: drbd_force_state(mdev, NS(disk, D_DISKLESS)); drbd_md_sync(mdev); - release_bdev2_fail: - if (nbc) - bd_release(nbc->md_bdev); - release_bdev_fail: - if (nbc) - bd_release(nbc->backing_bdev); fail: if (nbc) { - if (nbc->lo_file) - fput(nbc->lo_file); - if (nbc->md_file) - fput(nbc->md_file); + if (nbc->backing_bdev) + blkdev_put(nbc->backing_bdev, + FMODE_READ | FMODE_WRITE | FMODE_EXCL); + if (nbc->md_bdev) + blkdev_put(nbc->md_bdev, + FMODE_READ | FMODE_WRITE | FMODE_EXCL); kfree(nbc); } lc_destroy(resync_lru); diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c index 19b3568e9326..77d70eebb6b2 100644 --- a/drivers/block/pktcdvd.c +++ b/drivers/block/pktcdvd.c @@ -2296,15 +2296,12 @@ static int pkt_open_dev(struct pktcdvd_device *pd, fmode_t write) * so bdget() can't fail. */ bdget(pd->bdev->bd_dev); - if ((ret = blkdev_get(pd->bdev, FMODE_READ))) + if ((ret = blkdev_get(pd->bdev, FMODE_READ | FMODE_EXCL, pd))) goto out; - if ((ret = bd_claim(pd->bdev, pd))) - goto out_putdev; - if ((ret = pkt_get_last_written(pd, &lba))) { printk(DRIVER_NAME": pkt_get_last_written failed\n"); - goto out_unclaim; + goto out_putdev; } set_capacity(pd->disk, lba << 2); @@ -2314,7 +2311,7 @@ static int pkt_open_dev(struct pktcdvd_device *pd, fmode_t write) q = bdev_get_queue(pd->bdev); if (write) { if ((ret = pkt_open_write(pd))) - goto out_unclaim; + goto out_putdev; /* * Some CDRW drives can not handle writes larger than one packet, * even if the size is a multiple of the packet size. @@ -2329,23 +2326,21 @@ static int pkt_open_dev(struct pktcdvd_device *pd, fmode_t write) } if ((ret = pkt_set_segment_merging(pd, q))) - goto out_unclaim; + goto out_putdev; if (write) { if (!pkt_grow_pktlist(pd, CONFIG_CDROM_PKTCDVD_BUFFERS)) { printk(DRIVER_NAME": not enough memory for buffers\n"); ret = -ENOMEM; - goto out_unclaim; + goto out_putdev; } printk(DRIVER_NAME": %lukB available on disc\n", lba << 1); } return 0; -out_unclaim: - bd_release(pd->bdev); out_putdev: - blkdev_put(pd->bdev, FMODE_READ); + blkdev_put(pd->bdev, FMODE_READ | FMODE_EXCL); out: return ret; } @@ -2362,8 +2357,7 @@ static void pkt_release_dev(struct pktcdvd_device *pd, int flush) pkt_lock_door(pd, 0); pkt_set_speed(pd, MAX_SPEED, MAX_SPEED); - bd_release(pd->bdev); - blkdev_put(pd->bdev, FMODE_READ); + blkdev_put(pd->bdev, FMODE_READ | FMODE_EXCL); pkt_shrink_pktlist(pd); } @@ -2733,7 +2727,7 @@ static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev) bdev = bdget(dev); if (!bdev) return -ENOMEM; - ret = blkdev_get(bdev, FMODE_READ | FMODE_NDELAY); + ret = blkdev_get(bdev, FMODE_READ | FMODE_NDELAY, NULL); if (ret) return ret; diff --git a/drivers/char/raw.c b/drivers/char/raw.c index bfe25ea9766b..b4b9d5a47885 100644 --- a/drivers/char/raw.c +++ b/drivers/char/raw.c @@ -65,15 +65,12 @@ static int raw_open(struct inode *inode, struct file *filp) if (!bdev) goto out; igrab(bdev->bd_inode); - err = blkdev_get(bdev, filp->f_mode); + err = blkdev_get(bdev, filp->f_mode | FMODE_EXCL, raw_open); if (err) goto out; - err = bd_claim(bdev, raw_open); - if (err) - goto out1; err = set_blocksize(bdev, bdev_logical_block_size(bdev)); if (err) - goto out2; + goto out1; filp->f_flags |= O_DIRECT; filp->f_mapping = bdev->bd_inode->i_mapping; if (++raw_devices[minor].inuse == 1) @@ -83,10 +80,8 @@ static int raw_open(struct inode *inode, struct file *filp) mutex_unlock(&raw_mutex); return 0; -out2: - bd_release(bdev); out1: - blkdev_put(bdev, filp->f_mode); + blkdev_put(bdev, filp->f_mode | FMODE_EXCL); out: mutex_unlock(&raw_mutex); return err; @@ -110,8 +105,7 @@ static int raw_release(struct inode *inode, struct file *filp) } mutex_unlock(&raw_mutex); - bd_release(bdev); - blkdev_put(bdev, filp->f_mode); + blkdev_put(bdev, filp->f_mode | FMODE_EXCL); return 0; } diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 2c876ffc63df..9e88ca0c55e9 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -325,20 +325,13 @@ static int open_dev(struct dm_dev_internal *d, dev_t dev, BUG_ON(d->dm_dev.bdev); - bdev = open_by_devnum(dev, d->dm_dev.mode); + bdev = open_by_devnum(dev, d->dm_dev.mode | FMODE_EXCL, _claim_ptr); if (IS_ERR(bdev)) return PTR_ERR(bdev); - r = bd_claim(bdev, _claim_ptr); - if (r) { - blkdev_put(bdev, d->dm_dev.mode); - return r; - } - r = bd_link_disk_holder(bdev, dm_disk(md)); if (r) { - bd_release(bdev); - blkdev_put(bdev, d->dm_dev.mode); + blkdev_put(bdev, d->dm_dev.mode | FMODE_EXCL); return r; } @@ -354,9 +347,7 @@ static void close_dev(struct dm_dev_internal *d, struct mapped_device *md) if (!d->dm_dev.bdev) return; - bd_unlink_disk_holder(d->dm_dev.bdev); - bd_release(d->dm_dev.bdev); - blkdev_put(d->dm_dev.bdev, d->dm_dev.mode); + blkdev_put(d->dm_dev.bdev, d->dm_dev.mode | FMODE_EXCL); d->dm_dev.bdev = NULL; } diff --git a/drivers/md/md.c b/drivers/md/md.c index c47644fca1a1..6af951ffe0bb 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -1907,7 +1907,6 @@ static void unbind_rdev_from_array(mdk_rdev_t * rdev) MD_BUG(); return; } - bd_unlink_disk_holder(rdev->bdev); list_del_rcu(&rdev->same_set); printk(KERN_INFO "md: unbind<%s>\n", bdevname(rdev->bdev,b)); rdev->mddev = NULL; @@ -1935,19 +1934,13 @@ static int lock_rdev(mdk_rdev_t *rdev, dev_t dev, int shared) struct block_device *bdev; char b[BDEVNAME_SIZE]; - bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE); + bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, + shared ? (mdk_rdev_t *)lock_rdev : rdev); if (IS_ERR(bdev)) { printk(KERN_ERR "md: could not open %s.\n", __bdevname(dev, b)); return PTR_ERR(bdev); } - err = bd_claim(bdev, shared ? (mdk_rdev_t *)lock_rdev : rdev); - if (err) { - printk(KERN_ERR "md: could not bd_claim %s.\n", - bdevname(bdev, b)); - blkdev_put(bdev, FMODE_READ|FMODE_WRITE); - return err; - } if (!shared) set_bit(AllReserved, &rdev->flags); rdev->bdev = bdev; @@ -1960,8 +1953,7 @@ static void unlock_rdev(mdk_rdev_t *rdev) rdev->bdev = NULL; if (!bdev) MD_BUG(); - bd_release(bdev); - blkdev_put(bdev, FMODE_READ|FMODE_WRITE); + blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); } void md_autodetect_dev(dev_t dev); diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c index a9e2d3b38aeb..aa557beb8f51 100644 --- a/drivers/mtd/devices/block2mtd.c +++ b/drivers/mtd/devices/block2mtd.c @@ -224,7 +224,7 @@ static void block2mtd_free_device(struct block2mtd_dev *dev) if (dev->blkdev) { invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping, 0, -1); - close_bdev_exclusive(dev->blkdev, FMODE_READ|FMODE_WRITE); + blkdev_put(dev->blkdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); } kfree(dev); @@ -234,7 +234,7 @@ static void block2mtd_free_device(struct block2mtd_dev *dev) /* FIXME: ensure that mtd->size % erase_size == 0 */ static struct block2mtd_dev *add_device(char *devname, int erase_size) { - const fmode_t mode = FMODE_READ | FMODE_WRITE; + const fmode_t mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL; struct block_device *bdev; struct block2mtd_dev *dev; char *name; @@ -255,17 +255,8 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size) to resolve the device name by other means. */ dev_t devt = name_to_dev_t(devname); - if (devt) { - bdev = open_by_devnum(devt, mode); - if (!IS_ERR(bdev)) { - int ret; - ret = bd_claim(bdev, dev); - if (ret) { - blkdev_put(bdev, mode); - bdev = ERR_PTR(ret); - } - } - } + if (devt) + bdev = open_by_devnum(devt, mode, dev); } #endif diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c index 30a1ca3d08b7..5505bc07e1e7 100644 --- a/drivers/s390/block/dasd_genhd.c +++ b/drivers/s390/block/dasd_genhd.c @@ -103,7 +103,7 @@ int dasd_scan_partitions(struct dasd_block *block) struct block_device *bdev; bdev = bdget_disk(block->gdp, 0); - if (!bdev || blkdev_get(bdev, FMODE_READ) < 0) + if (!bdev || blkdev_get(bdev, FMODE_READ, NULL) < 0) return -ENODEV; /* * See fs/partition/check.c:register_disk,rescan_partitions diff --git a/fs/block_dev.c b/fs/block_dev.c index 9329068684d2..fc48912354d1 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -660,7 +660,7 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, else if (bdev->bd_contains == bdev) return true; /* is a whole device which isn't held */ - else if (whole->bd_holder == bd_claim) + else if (whole->bd_holder == bd_may_claim) return true; /* is a partition of a device that is being partitioned */ else if (whole->bd_holder != NULL) return false; /* is a partition of a held device */ @@ -807,10 +807,10 @@ static void __bd_claim(struct block_device *bdev, struct block_device *whole, { /* note that for a whole device bd_holders * will be incremented twice, and bd_holder will - * be set to bd_claim before being set to holder + * be set to bd_may_claim before being set to holder */ whole->bd_holders++; - whole->bd_holder = bd_claim; + whole->bd_holder = bd_may_claim; bdev->bd_holders++; bdev->bd_holder = holder; } @@ -835,37 +835,7 @@ static void bd_finish_claiming(struct block_device *bdev, __bd_abort_claiming(whole, holder); /* not actually an abort */ } -/** - * bd_claim - claim a block device - * @bdev: block device to claim - * @holder: holder trying to claim @bdev - * - * Try to claim @bdev which must have been opened successfully. - * - * CONTEXT: - * Might sleep. - * - * RETURNS: - * 0 if successful, -EBUSY if @bdev is already claimed. - */ -int bd_claim(struct block_device *bdev, void *holder) -{ - struct block_device *whole = bdev->bd_contains; - int res; - - might_sleep(); - - spin_lock(&bdev_lock); - res = bd_prepare_to_claim(bdev, whole, holder); - if (res == 0) - __bd_claim(bdev, whole, holder); - spin_unlock(&bdev_lock); - - return res; -} -EXPORT_SYMBOL(bd_claim); - -void bd_release(struct block_device *bdev) +static void bd_release(struct block_device *bdev) { spin_lock(&bdev_lock); if (!--bdev->bd_contains->bd_holders) @@ -875,8 +845,6 @@ void bd_release(struct block_device *bdev) spin_unlock(&bdev_lock); } -EXPORT_SYMBOL(bd_release); - #ifdef CONFIG_SYSFS static int add_symlink(struct kobject *from, struct kobject *to) { @@ -943,7 +911,7 @@ out_unlock: } EXPORT_SYMBOL_GPL(bd_link_disk_holder); -void bd_unlink_disk_holder(struct block_device *bdev) +static void bd_unlink_disk_holder(struct block_device *bdev) { struct gendisk *disk = bdev->bd_holder_disk; @@ -954,7 +922,9 @@ void bd_unlink_disk_holder(struct block_device *bdev) del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); del_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj); } -EXPORT_SYMBOL_GPL(bd_unlink_disk_holder); +#else +static inline void bd_unlink_disk_holder(struct block_device *bdev) +{ } #endif /* @@ -964,12 +934,12 @@ EXPORT_SYMBOL_GPL(bd_unlink_disk_holder); * to be used for internal purposes. If you ever need it - reconsider * your API. */ -struct block_device *open_by_devnum(dev_t dev, fmode_t mode) +struct block_device *open_by_devnum(dev_t dev, fmode_t mode, void *holder) { struct block_device *bdev = bdget(dev); int err = -ENOMEM; if (bdev) - err = blkdev_get(bdev, mode); + err = blkdev_get(bdev, mode, holder); return err ? ERR_PTR(err) : bdev; } @@ -1235,17 +1205,37 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) return ret; } -int blkdev_get(struct block_device *bdev, fmode_t mode) +int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) { - return __blkdev_get(bdev, mode, 0); + struct block_device *whole = NULL; + int res; + + WARN_ON_ONCE((mode & FMODE_EXCL) && !holder); + + if ((mode & FMODE_EXCL) && holder) { + whole = bd_start_claiming(bdev, holder); + if (IS_ERR(whole)) { + bdput(bdev); + return PTR_ERR(whole); + } + } + + res = __blkdev_get(bdev, mode, 0); + + if (whole) { + if (res == 0) + bd_finish_claiming(bdev, whole, holder); + else + bd_abort_claiming(whole, holder); + } + + return res; } EXPORT_SYMBOL(blkdev_get); static int blkdev_open(struct inode * inode, struct file * filp) { - struct block_device *whole = NULL; struct block_device *bdev; - int res; /* * Preserve backwards compatibility and allow large file access @@ -1266,26 +1256,9 @@ static int blkdev_open(struct inode * inode, struct file * filp) if (bdev == NULL) return -ENOMEM; - if (filp->f_mode & FMODE_EXCL) { - whole = bd_start_claiming(bdev, filp); - if (IS_ERR(whole)) { - bdput(bdev); - return PTR_ERR(whole); - } - } - filp->f_mapping = bdev->bd_inode->i_mapping; - res = blkdev_get(bdev, filp->f_mode); - - if (whole) { - if (res == 0) - bd_finish_claiming(bdev, whole, filp); - else - bd_abort_claiming(whole, filp); - } - - return res; + return blkdev_get(bdev, filp->f_mode, filp); } static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) @@ -1329,6 +1302,13 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) int blkdev_put(struct block_device *bdev, fmode_t mode) { + if (mode & FMODE_EXCL) { + mutex_lock(&bdev->bd_mutex); + bd_release(bdev); + if (!bdev->bd_holders) + bd_unlink_disk_holder(bdev); + mutex_unlock(&bdev->bd_mutex); + } return __blkdev_put(bdev, mode, 0); } EXPORT_SYMBOL(blkdev_put); @@ -1336,8 +1316,7 @@ EXPORT_SYMBOL(blkdev_put); static int blkdev_close(struct inode * inode, struct file * filp) { struct block_device *bdev = I_BDEV(filp->f_mapping->host); - if (bdev->bd_holder == filp) - bd_release(bdev); + return blkdev_put(bdev, filp->f_mode); } @@ -1494,55 +1473,27 @@ EXPORT_SYMBOL(lookup_bdev); */ struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder) { - struct block_device *bdev, *whole; + struct block_device *bdev; int error; bdev = lookup_bdev(path); if (IS_ERR(bdev)) return bdev; - whole = bd_start_claiming(bdev, holder); - if (IS_ERR(whole)) { - bdput(bdev); - return whole; - } - - error = blkdev_get(bdev, mode); + error = blkdev_get(bdev, mode | FMODE_EXCL, holder); if (error) - goto out_abort_claiming; + return ERR_PTR(error); - error = -EACCES; - if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) - goto out_blkdev_put; + if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) { + blkdev_put(bdev, mode); + return ERR_PTR(-EACCES); + } - bd_finish_claiming(bdev, whole, holder); return bdev; - -out_blkdev_put: - blkdev_put(bdev, mode); -out_abort_claiming: - bd_abort_claiming(whole, holder); - return ERR_PTR(error); } EXPORT_SYMBOL(open_bdev_exclusive); -/** - * close_bdev_exclusive - close a blockdevice opened by open_bdev_exclusive() - * - * @bdev: blockdevice to close - * @mode: mode, must match that used to open. - * - * This is the counterpart to open_bdev_exclusive(). - */ -void close_bdev_exclusive(struct block_device *bdev, fmode_t mode) -{ - bd_release(bdev); - blkdev_put(bdev, mode); -} - -EXPORT_SYMBOL(close_bdev_exclusive); - int __invalidate_device(struct block_device *bdev) { struct super_block *sb = get_super(bdev); diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index d39596224d21..f1b729d3b883 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -489,7 +489,7 @@ again: continue; if (device->bdev) { - close_bdev_exclusive(device->bdev, device->mode); + blkdev_put(device->bdev, device->mode | FMODE_EXCL); device->bdev = NULL; fs_devices->open_devices--; } @@ -523,7 +523,7 @@ static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices) list_for_each_entry(device, &fs_devices->devices, dev_list) { if (device->bdev) { - close_bdev_exclusive(device->bdev, device->mode); + blkdev_put(device->bdev, device->mode | FMODE_EXCL); fs_devices->open_devices--; } if (device->writeable) { @@ -638,7 +638,7 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices, error_brelse: brelse(bh); error_close: - close_bdev_exclusive(bdev, flags); + blkdev_put(bdev, flags | FMODE_EXCL); error: continue; } @@ -716,7 +716,7 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, brelse(bh); error_close: - close_bdev_exclusive(bdev, flags); + blkdev_put(bdev, flags | FMODE_EXCL); error: mutex_unlock(&uuid_mutex); return ret; @@ -1244,7 +1244,7 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path) root->fs_info->fs_devices->latest_bdev = next_device->bdev; if (device->bdev) { - close_bdev_exclusive(device->bdev, device->mode); + blkdev_put(device->bdev, device->mode | FMODE_EXCL); device->bdev = NULL; device->fs_devices->open_devices--; } @@ -1287,7 +1287,7 @@ error_brelse: brelse(bh); error_close: if (bdev) - close_bdev_exclusive(bdev, FMODE_READ); + blkdev_put(bdev, FMODE_READ | FMODE_EXCL); out: mutex_unlock(&root->fs_info->volume_mutex); mutex_unlock(&uuid_mutex); @@ -1565,7 +1565,7 @@ out: mutex_unlock(&root->fs_info->volume_mutex); return ret; error: - close_bdev_exclusive(bdev, 0); + blkdev_put(bdev, FMODE_EXCL); if (seeding_dev) { mutex_unlock(&uuid_mutex); up_write(&sb->s_umount); diff --git a/fs/ext3/super.c b/fs/ext3/super.c index 2fedaf8b5012..23e7513dba9c 100644 --- a/fs/ext3/super.c +++ b/fs/ext3/super.c @@ -347,7 +347,7 @@ static struct block_device *ext3_blkdev_get(dev_t dev, struct super_block *sb) struct block_device *bdev; char b[BDEVNAME_SIZE]; - bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE); + bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb); if (IS_ERR(bdev)) goto fail; return bdev; @@ -364,8 +364,7 @@ fail: */ static int ext3_blkdev_put(struct block_device *bdev) { - bd_release(bdev); - return blkdev_put(bdev, FMODE_READ|FMODE_WRITE); + return blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); } static int ext3_blkdev_remove(struct ext3_sb_info *sbi) @@ -2136,13 +2135,6 @@ static journal_t *ext3_get_dev_journal(struct super_block *sb, if (bdev == NULL) return NULL; - if (bd_claim(bdev, sb)) { - ext3_msg(sb, KERN_ERR, - "error: failed to claim external journal device"); - blkdev_put(bdev, FMODE_READ|FMODE_WRITE); - return NULL; - } - blocksize = sb->s_blocksize; hblock = bdev_logical_block_size(bdev); if (blocksize < hblock) { diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 61182fe6254e..5dd0b3e76fa8 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -647,7 +647,7 @@ static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb) struct block_device *bdev; char b[BDEVNAME_SIZE]; - bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE); + bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb); if (IS_ERR(bdev)) goto fail; return bdev; @@ -663,8 +663,7 @@ fail: */ static int ext4_blkdev_put(struct block_device *bdev) { - bd_release(bdev); - return blkdev_put(bdev, FMODE_READ|FMODE_WRITE); + return blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); } static int ext4_blkdev_remove(struct ext4_sb_info *sbi) @@ -3758,13 +3757,6 @@ static journal_t *ext4_get_dev_journal(struct super_block *sb, if (bdev == NULL) return NULL; - if (bd_claim(bdev, sb)) { - ext4_msg(sb, KERN_ERR, - "failed to claim external journal device"); - blkdev_put(bdev, FMODE_READ|FMODE_WRITE); - return NULL; - } - blocksize = sb->s_blocksize; hblock = bdev_logical_block_size(bdev); if (blocksize < hblock) { diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index 3eb1393f7b81..c1f0763a022b 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -1298,7 +1298,7 @@ static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags, goto error_bdev; if (s->s_root) - close_bdev_exclusive(bdev, mode); + blkdev_put(bdev, mode | FMODE_EXCL); memset(&args, 0, sizeof(args)); args.ar_quota = GFS2_QUOTA_DEFAULT; @@ -1342,7 +1342,7 @@ error_super: deactivate_locked_super(s); return ERR_PTR(error); error_bdev: - close_bdev_exclusive(bdev, mode); + blkdev_put(bdev, mode | FMODE_EXCL); return ERR_PTR(error); } diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c index e1b8493b9aaa..5a290f22dcc3 100644 --- a/fs/jfs/jfs_logmgr.c +++ b/fs/jfs/jfs_logmgr.c @@ -1120,16 +1120,13 @@ int lmLogOpen(struct super_block *sb) * file systems to log may have n-to-1 relationship; */ - bdev = open_by_devnum(sbi->logdev, FMODE_READ|FMODE_WRITE); + bdev = open_by_devnum(sbi->logdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, + log); if (IS_ERR(bdev)) { rc = -PTR_ERR(bdev); goto free; } - if ((rc = bd_claim(bdev, log))) { - goto close; - } - log->bdev = bdev; memcpy(log->uuid, sbi->loguuid, sizeof(log->uuid)); @@ -1137,7 +1134,7 @@ int lmLogOpen(struct super_block *sb) * initialize log: */ if ((rc = lmLogInit(log))) - goto unclaim; + goto close; list_add(&log->journal_list, &jfs_external_logs); @@ -1163,11 +1160,8 @@ journal_found: list_del(&log->journal_list); lbmLogShutdown(log); - unclaim: - bd_release(bdev); - close: /* close external log device */ - blkdev_put(bdev, FMODE_READ|FMODE_WRITE); + blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); free: /* free log descriptor */ mutex_unlock(&jfs_log_mutex); @@ -1512,8 +1506,7 @@ int lmLogClose(struct super_block *sb) bdev = log->bdev; rc = lmLogShutdown(log); - bd_release(bdev); - blkdev_put(bdev, FMODE_READ|FMODE_WRITE); + blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); kfree(log); diff --git a/fs/logfs/dev_bdev.c b/fs/logfs/dev_bdev.c index 92ca6fbe09bd..734b9025858e 100644 --- a/fs/logfs/dev_bdev.c +++ b/fs/logfs/dev_bdev.c @@ -300,7 +300,7 @@ static int bdev_write_sb(struct super_block *sb, struct page *page) static void bdev_put_device(struct logfs_super *s) { - close_bdev_exclusive(s->s_bdev, FMODE_READ|FMODE_WRITE); + blkdev_put(s->s_bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); } static int bdev_can_write_buf(struct super_block *sb, u64 ofs) @@ -331,7 +331,7 @@ int logfs_get_sb_bdev(struct logfs_super *p, struct file_system_type *type, if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) { int mtdnr = MINOR(bdev->bd_dev); - close_bdev_exclusive(bdev, FMODE_READ|FMODE_WRITE); + blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); return logfs_get_sb_mtd(p, mtdnr); } diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c index f804d41ec9d3..756a6798d7c8 100644 --- a/fs/nilfs2/super.c +++ b/fs/nilfs2/super.c @@ -1233,7 +1233,7 @@ nilfs_mount(struct file_system_type *fs_type, int flags, } if (!s_new) - close_bdev_exclusive(sd.bdev, mode); + blkdev_put(sd.bdev, mode | FMODE_EXCL); return root_dentry; @@ -1242,7 +1242,7 @@ nilfs_mount(struct file_system_type *fs_type, int flags, failed: if (!s_new) - close_bdev_exclusive(sd.bdev, mode); + blkdev_put(sd.bdev, mode | FMODE_EXCL); return ERR_PTR(err); } diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c index 52c7557f3e25..d0a2721eaceb 100644 --- a/fs/ocfs2/cluster/heartbeat.c +++ b/fs/ocfs2/cluster/heartbeat.c @@ -1674,7 +1674,7 @@ static ssize_t o2hb_region_dev_write(struct o2hb_region *reg, goto out; reg->hr_bdev = I_BDEV(filp->f_mapping->host); - ret = blkdev_get(reg->hr_bdev, FMODE_WRITE | FMODE_READ); + ret = blkdev_get(reg->hr_bdev, FMODE_WRITE | FMODE_READ, NULL); if (ret) { reg->hr_bdev = NULL; goto out; diff --git a/fs/partitions/check.c b/fs/partitions/check.c index 0a8b0ad0c7e2..2e6501d034ab 100644 --- a/fs/partitions/check.c +++ b/fs/partitions/check.c @@ -549,7 +549,7 @@ void register_disk(struct gendisk *disk) goto exit; bdev->bd_invalidated = 1; - err = blkdev_get(bdev, FMODE_READ); + err = blkdev_get(bdev, FMODE_READ, NULL); if (err < 0) goto exit; blkdev_put(bdev, FMODE_READ); diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c index 076c8b194682..b488136f5ace 100644 --- a/fs/reiserfs/journal.c +++ b/fs/reiserfs/journal.c @@ -2552,8 +2552,6 @@ static int release_journal_dev(struct super_block *super, result = 0; if (journal->j_dev_bd != NULL) { - if (journal->j_dev_bd->bd_dev != super->s_dev) - bd_release(journal->j_dev_bd); result = blkdev_put(journal->j_dev_bd, journal->j_dev_mode); journal->j_dev_bd = NULL; } @@ -2571,7 +2569,7 @@ static int journal_init_dev(struct super_block *super, { int result; dev_t jdev; - fmode_t blkdev_mode = FMODE_READ | FMODE_WRITE; + fmode_t blkdev_mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL; char b[BDEVNAME_SIZE]; result = 0; @@ -2585,7 +2583,9 @@ static int journal_init_dev(struct super_block *super, /* there is no "jdev" option and journal is on separate device */ if ((!jdev_name || !jdev_name[0])) { - journal->j_dev_bd = open_by_devnum(jdev, blkdev_mode); + if (jdev == super->s_dev) + blkdev_mode &= ~FMODE_EXCL; + journal->j_dev_bd = open_by_devnum(jdev, blkdev_mode, journal); journal->j_dev_mode = blkdev_mode; if (IS_ERR(journal->j_dev_bd)) { result = PTR_ERR(journal->j_dev_bd); @@ -2594,15 +2594,8 @@ static int journal_init_dev(struct super_block *super, "cannot init journal device '%s': %i", __bdevname(jdev, b), result); return result; - } else if (jdev != super->s_dev) { - result = bd_claim(journal->j_dev_bd, journal); - if (result) { - blkdev_put(journal->j_dev_bd, blkdev_mode); - return result; - } - + } else if (jdev != super->s_dev) set_blocksize(journal->j_dev_bd, super->s_blocksize); - } return 0; } diff --git a/fs/super.c b/fs/super.c index ca696155cd9a..22374bf0ba87 100644 --- a/fs/super.c +++ b/fs/super.c @@ -801,13 +801,13 @@ struct dentry *mount_bdev(struct file_system_type *fs_type, /* * s_umount nests inside bd_mutex during - * __invalidate_device(). close_bdev_exclusive() - * acquires bd_mutex and can't be called under - * s_umount. Drop s_umount temporarily. This is safe - * as we're holding an active reference. + * __invalidate_device(). blkdev_put() acquires + * bd_mutex and can't be called under s_umount. Drop + * s_umount temporarily. This is safe as we're + * holding an active reference. */ up_write(&s->s_umount); - close_bdev_exclusive(bdev, mode); + blkdev_put(bdev, mode | FMODE_EXCL); down_write(&s->s_umount); } else { char b[BDEVNAME_SIZE]; @@ -831,7 +831,7 @@ struct dentry *mount_bdev(struct file_system_type *fs_type, error_s: error = PTR_ERR(s); error_bdev: - close_bdev_exclusive(bdev, mode); + blkdev_put(bdev, mode | FMODE_EXCL); error: return ERR_PTR(error); } @@ -862,7 +862,7 @@ void kill_block_super(struct super_block *sb) bdev->bd_super = NULL; generic_shutdown_super(sb); sync_blockdev(bdev); - close_bdev_exclusive(bdev, mode); + blkdev_put(bdev, mode | FMODE_EXCL); } EXPORT_SYMBOL(kill_block_super); diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c index 9f3a78fe6ae4..a1a6e5ceea67 100644 --- a/fs/xfs/linux-2.6/xfs_super.c +++ b/fs/xfs/linux-2.6/xfs_super.c @@ -623,7 +623,7 @@ xfs_blkdev_put( struct block_device *bdev) { if (bdev) - close_bdev_exclusive(bdev, FMODE_READ|FMODE_WRITE); + blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); } /* diff --git a/include/linux/fs.h b/include/linux/fs.h index 66b7f2c5d7e9..1a033e8ebe4c 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2006,7 +2006,8 @@ extern struct block_device *bdgrab(struct block_device *bdev); extern void bd_set_size(struct block_device *, loff_t size); extern void bd_forget(struct inode *inode); extern void bdput(struct block_device *); -extern struct block_device *open_by_devnum(dev_t, fmode_t); +extern struct block_device *open_by_devnum(dev_t dev, fmode_t mode, + void *holder); extern void invalidate_bdev(struct block_device *); extern int sync_blockdev(struct block_device *bdev); extern struct super_block *freeze_bdev(struct block_device *); @@ -2037,22 +2038,16 @@ extern const struct file_operations def_fifo_fops; extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long); extern int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long); extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long); -extern int blkdev_get(struct block_device *, fmode_t); -extern int blkdev_put(struct block_device *, fmode_t); -extern int bd_claim(struct block_device *, void *); -extern void bd_release(struct block_device *); +extern int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder); +extern int blkdev_put(struct block_device *bdev, fmode_t mode); #ifdef CONFIG_SYSFS extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk); -extern void bd_unlink_disk_holder(struct block_device *bdev); #else static inline int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) { return 0; } -static inline void bd_unlink_disk_holder(struct block_device *bdev) -{ -} #endif #endif @@ -2089,7 +2084,6 @@ extern const char *__bdevname(dev_t, char *buffer); extern const char *bdevname(struct block_device *bdev, char *buffer); extern struct block_device *lookup_bdev(const char *); extern struct block_device *open_bdev_exclusive(const char *, fmode_t, void *); -extern void close_bdev_exclusive(struct block_device *, fmode_t); extern void blkdev_show(struct seq_file *,off_t); #else diff --git a/kernel/power/swap.c b/kernel/power/swap.c index a0e4a86ccf94..513a77f1a0b3 100644 --- a/kernel/power/swap.c +++ b/kernel/power/swap.c @@ -223,7 +223,7 @@ static int swsusp_swap_check(void) return res; root_swap = res; - res = blkdev_get(hib_resume_bdev, FMODE_WRITE); + res = blkdev_get(hib_resume_bdev, FMODE_WRITE, NULL); if (res) return res; @@ -907,7 +907,8 @@ int swsusp_check(void) { int error; - hib_resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ); + hib_resume_bdev = open_by_devnum(swsusp_resume_device, + FMODE_READ, NULL); if (!IS_ERR(hib_resume_bdev)) { set_blocksize(hib_resume_bdev, PAGE_SIZE); clear_page(swsusp_header); diff --git a/mm/swapfile.c b/mm/swapfile.c index 67ddaaf98c74..b6adcfbf6f48 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1677,7 +1677,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) if (S_ISBLK(inode->i_mode)) { struct block_device *bdev = I_BDEV(inode); set_blocksize(bdev, p->old_block_size); - bd_release(bdev); + blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); } else { mutex_lock(&inode->i_mutex); inode->i_flags &= ~S_SWAPFILE; @@ -1939,7 +1939,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) error = -EINVAL; if (S_ISBLK(inode->i_mode)) { bdev = I_BDEV(inode); - error = bd_claim(bdev, sys_swapon); + error = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL, + sys_swapon); if (error < 0) { bdev = NULL; error = -EINVAL; @@ -2136,7 +2137,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) bad_swap: if (bdev) { set_blocksize(bdev, p->old_block_size); - bd_release(bdev); + blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); } destroy_swap_extents(p); swap_cgroup_swapoff(type); -- cgit v1.2.3 From 6a027eff62f6ae32d49f2ae5dadd6f4eee1ddae2 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sat, 13 Nov 2010 11:55:17 +0100 Subject: block: reorganize claim/release implementation With claim/release rolled into blkdev_get/put(), there's no reason to keep bd_abort/finish_claim(), __bd_claim() and bd_release() as separate functions. It only makes the code difficult to follow. Collapse them into blkdev_get/put(). This will ease future changes around claim/release. Signed-off-by: Tejun Heo --- fs/block_dev.c | 127 ++++++++++++++++++++++----------------------------------- 1 file changed, 48 insertions(+), 79 deletions(-) (limited to 'fs/block_dev.c') diff --git a/fs/block_dev.c b/fs/block_dev.c index fc48912354d1..269bfbbd10fc 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -772,79 +772,6 @@ static struct block_device *bd_start_claiming(struct block_device *bdev, } } -/* releases bdev_lock */ -static void __bd_abort_claiming(struct block_device *whole, void *holder) -{ - BUG_ON(whole->bd_claiming != holder); - whole->bd_claiming = NULL; - wake_up_bit(&whole->bd_claiming, 0); - - spin_unlock(&bdev_lock); - bdput(whole); -} - -/** - * bd_abort_claiming - abort claiming a block device - * @whole: whole block device returned by bd_start_claiming() - * @holder: holder trying to claim @bdev - * - * Abort a claiming block started by bd_start_claiming(). Note that - * @whole is not the block device to be claimed but the whole device - * returned by bd_start_claiming(). - * - * CONTEXT: - * Grabs and releases bdev_lock. - */ -static void bd_abort_claiming(struct block_device *whole, void *holder) -{ - spin_lock(&bdev_lock); - __bd_abort_claiming(whole, holder); /* releases bdev_lock */ -} - -/* increment holders when we have a legitimate claim. requires bdev_lock */ -static void __bd_claim(struct block_device *bdev, struct block_device *whole, - void *holder) -{ - /* note that for a whole device bd_holders - * will be incremented twice, and bd_holder will - * be set to bd_may_claim before being set to holder - */ - whole->bd_holders++; - whole->bd_holder = bd_may_claim; - bdev->bd_holders++; - bdev->bd_holder = holder; -} - -/** - * bd_finish_claiming - finish claiming a block device - * @bdev: block device of interest (passed to bd_start_claiming()) - * @whole: whole block device returned by bd_start_claiming() - * @holder: holder trying to claim @bdev - * - * Finish a claiming block started by bd_start_claiming(). - * - * CONTEXT: - * Grabs and releases bdev_lock. - */ -static void bd_finish_claiming(struct block_device *bdev, - struct block_device *whole, void *holder) -{ - spin_lock(&bdev_lock); - BUG_ON(!bd_may_claim(bdev, whole, holder)); - __bd_claim(bdev, whole, holder); - __bd_abort_claiming(whole, holder); /* not actually an abort */ -} - -static void bd_release(struct block_device *bdev) -{ - spin_lock(&bdev_lock); - if (!--bdev->bd_contains->bd_holders) - bdev->bd_contains->bd_holder = NULL; - if (!--bdev->bd_holders) - bdev->bd_holder = NULL; - spin_unlock(&bdev_lock); -} - #ifdef CONFIG_SYSFS static int add_symlink(struct kobject *from, struct kobject *to) { @@ -1223,10 +1150,30 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) res = __blkdev_get(bdev, mode, 0); if (whole) { - if (res == 0) - bd_finish_claiming(bdev, whole, holder); - else - bd_abort_claiming(whole, holder); + /* finish claiming */ + spin_lock(&bdev_lock); + + if (res == 0) { + BUG_ON(!bd_may_claim(bdev, whole, holder)); + /* + * Note that for a whole device bd_holders + * will be incremented twice, and bd_holder + * will be set to bd_may_claim before being + * set to holder + */ + whole->bd_holders++; + whole->bd_holder = bd_may_claim; + bdev->bd_holders++; + bdev->bd_holder = holder; + } + + /* tell others that we're done */ + BUG_ON(whole->bd_claiming != holder); + whole->bd_claiming = NULL; + wake_up_bit(&whole->bd_claiming, 0); + + spin_unlock(&bdev_lock); + bdput(whole); } return res; @@ -1272,6 +1219,7 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) bdev->bd_part_count--; if (!--bdev->bd_openers) { + WARN_ON_ONCE(bdev->bd_holders); sync_blockdev(bdev); kill_bdev(bdev); } @@ -1303,10 +1251,31 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) int blkdev_put(struct block_device *bdev, fmode_t mode) { if (mode & FMODE_EXCL) { + bool bdev_free; + + /* + * Release a claim on the device. The holder fields + * are protected with bdev_lock. bd_mutex is to + * synchronize disk_holder unlinking. + */ mutex_lock(&bdev->bd_mutex); - bd_release(bdev); - if (!bdev->bd_holders) + spin_lock(&bdev_lock); + + WARN_ON_ONCE(--bdev->bd_holders < 0); + WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0); + + /* bd_contains might point to self, check in a separate step */ + if ((bdev_free = !bdev->bd_holders)) + bdev->bd_holder = NULL; + if (!bdev->bd_contains->bd_holders) + bdev->bd_contains->bd_holder = NULL; + + spin_unlock(&bdev_lock); + + /* if this was the last claim, holder link should go too */ + if (bdev_free) bd_unlink_disk_holder(bdev); + mutex_unlock(&bdev->bd_mutex); } return __blkdev_put(bdev, mode, 0); -- cgit v1.2.3 From 75f1dc0d076d1c1168f2115f1941ea627d38bd5a Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sat, 13 Nov 2010 11:55:17 +0100 Subject: block: check bdev_read_only() from blkdev_get() bdev read-only status can be queried using bdev_read_only() and may change while the device is being opened. Enforce it by checking it from blkdev_get() after open succeeds. This makes bdev_read_only() check in open_bdev_exclusive() and fsg_lun_open() unnecessary. Drop them. Signed-off-by: Tejun Heo Cc: David Brownell Cc: linux-usb@vger.kernel.org --- drivers/usb/gadget/storage_common.c | 7 ++----- fs/block_dev.c | 11 ++++++----- 2 files changed, 8 insertions(+), 10 deletions(-) (limited to 'fs/block_dev.c') diff --git a/drivers/usb/gadget/storage_common.c b/drivers/usb/gadget/storage_common.c index 3b513bafaf2a..b015561fd602 100644 --- a/drivers/usb/gadget/storage_common.c +++ b/drivers/usb/gadget/storage_common.c @@ -543,7 +543,7 @@ static int fsg_lun_open(struct fsg_lun *curlun, const char *filename) ro = curlun->initially_ro; if (!ro) { filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0); - if (-EROFS == PTR_ERR(filp)) + if (PTR_ERR(filp) == -EROFS || PTR_ERR(filp) == -EACCES) ro = 1; } if (ro) @@ -558,10 +558,7 @@ static int fsg_lun_open(struct fsg_lun *curlun, const char *filename) if (filp->f_path.dentry) inode = filp->f_path.dentry->d_inode; - if (inode && S_ISBLK(inode->i_mode)) { - if (bdev_read_only(inode->i_bdev)) - ro = 1; - } else if (!inode || !S_ISREG(inode->i_mode)) { + if (!inode || (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) { LINFO(curlun, "invalid file type: %s\n", filename); goto out; } diff --git a/fs/block_dev.c b/fs/block_dev.c index 269bfbbd10fc..606a5259f87f 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1149,6 +1149,12 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) res = __blkdev_get(bdev, mode, 0); + /* __blkdev_get() may alter read only status, check it afterwards */ + if (!res && (mode & FMODE_WRITE) && bdev_read_only(bdev)) { + __blkdev_put(bdev, mode, 0); + res = -EACCES; + } + if (whole) { /* finish claiming */ spin_lock(&bdev_lock); @@ -1453,11 +1459,6 @@ struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *h if (error) return ERR_PTR(error); - if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) { - blkdev_put(bdev, mode); - return ERR_PTR(-EACCES); - } - return bdev; } -- cgit v1.2.3 From d4d77629953eabd3c14f6fa5746f6b28babfc55f Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sat, 13 Nov 2010 11:55:18 +0100 Subject: block: clean up blkdev_get() wrappers and their users After recent blkdev_get() modifications, open_by_devnum() and open_bdev_exclusive() are simple wrappers around blkdev_get(). Replace them with blkdev_get_by_dev() and blkdev_get_by_path(). blkdev_get_by_dev() is identical to open_by_devnum(). blkdev_get_by_path() is slightly different in that it doesn't automatically add %FMODE_EXCL to @mode. All users are converted. Most conversions are mechanical and don't introduce any behavior difference. There are several exceptions. * btrfs now sets FMODE_EXCL in btrfs_device->mode, so there's no reason to OR it explicitly on blkdev_put(). * gfs2, nilfs2 and the generic mount_bdev() now set FMODE_EXCL in sb->s_mode. * With the above changes, sb->s_mode now always should contain FMODE_EXCL. WARN_ON_ONCE() added to kill_block_super() to detect errors. The new blkdev_get_*() functions are with proper docbook comments. While at it, add function description to blkdev_get() too. Signed-off-by: Tejun Heo Cc: Philipp Reisner Cc: Neil Brown Cc: Mike Snitzer Cc: Joern Engel Cc: Chris Mason Cc: Jan Kara Cc: "Theodore Ts'o" Cc: KONISHI Ryusuke Cc: reiserfs-devel@vger.kernel.org Cc: xfs-masters@oss.sgi.com Cc: Alexander Viro --- drivers/block/drbd/drbd_nl.c | 12 ++-- drivers/md/dm-table.c | 2 +- drivers/md/md.c | 4 +- drivers/mtd/devices/block2mtd.c | 4 +- fs/block_dev.c | 139 +++++++++++++++++++++++++++------------- fs/btrfs/volumes.c | 24 ++++--- fs/btrfs/volumes.h | 2 +- fs/ext3/super.c | 2 +- fs/ext4/super.c | 2 +- fs/gfs2/ops_fstype.c | 8 +-- fs/jfs/jfs_logmgr.c | 4 +- fs/logfs/dev_bdev.c | 3 +- fs/nilfs2/super.c | 8 +-- fs/reiserfs/journal.c | 6 +- fs/super.c | 9 +-- fs/xfs/linux-2.6/xfs_super.c | 3 +- include/linux/fs.h | 7 +- kernel/power/swap.c | 4 +- 18 files changed, 149 insertions(+), 94 deletions(-) (limited to 'fs/block_dev.c') diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index fd0346090289..650e43ba4f7c 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -902,8 +902,8 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp } } - bdev = open_bdev_exclusive(nbc->dc.backing_dev, - FMODE_READ | FMODE_WRITE, mdev); + bdev = blkdev_get_by_path(nbc->dc.backing_dev, + FMODE_READ | FMODE_WRITE | FMODE_EXCL, mdev); if (IS_ERR(bdev)) { dev_err(DEV, "open(\"%s\") failed with %ld\n", nbc->dc.backing_dev, PTR_ERR(bdev)); @@ -920,10 +920,10 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp * should check it for you already; but if you don't, or * someone fooled it, we need to double check here) */ - bdev = open_bdev_exclusive(nbc->dc.meta_dev, - FMODE_READ | FMODE_WRITE, - (nbc->dc.meta_dev_idx < 0) ? - (void *)mdev : (void *)drbd_m_holder); + bdev = blkdev_get_by_path(nbc->dc.meta_dev, + FMODE_READ | FMODE_WRITE | FMODE_EXCL, + (nbc->dc.meta_dev_idx < 0) ? + (void *)mdev : (void *)drbd_m_holder); if (IS_ERR(bdev)) { dev_err(DEV, "open(\"%s\") failed with %ld\n", nbc->dc.meta_dev, PTR_ERR(bdev)); diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 9e88ca0c55e9..67150c32986c 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -325,7 +325,7 @@ static int open_dev(struct dm_dev_internal *d, dev_t dev, BUG_ON(d->dm_dev.bdev); - bdev = open_by_devnum(dev, d->dm_dev.mode | FMODE_EXCL, _claim_ptr); + bdev = blkdev_get_by_dev(dev, d->dm_dev.mode | FMODE_EXCL, _claim_ptr); if (IS_ERR(bdev)) return PTR_ERR(bdev); diff --git a/drivers/md/md.c b/drivers/md/md.c index 6af951ffe0bb..5aaa6bfbe638 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -1934,8 +1934,8 @@ static int lock_rdev(mdk_rdev_t *rdev, dev_t dev, int shared) struct block_device *bdev; char b[BDEVNAME_SIZE]; - bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, - shared ? (mdk_rdev_t *)lock_rdev : rdev); + bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, + shared ? (mdk_rdev_t *)lock_rdev : rdev); if (IS_ERR(bdev)) { printk(KERN_ERR "md: could not open %s.\n", __bdevname(dev, b)); diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c index aa557beb8f51..f29a6f9df6e7 100644 --- a/drivers/mtd/devices/block2mtd.c +++ b/drivers/mtd/devices/block2mtd.c @@ -247,7 +247,7 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size) return NULL; /* Get a handle on the device */ - bdev = open_bdev_exclusive(devname, mode, dev); + bdev = blkdev_get_by_path(devname, mode, dev); #ifndef MODULE if (IS_ERR(bdev)) { @@ -256,7 +256,7 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size) dev_t devt = name_to_dev_t(devname); if (devt) - bdev = open_by_devnum(devt, mode, dev); + bdev = blkdev_get_by_dev(devt, mode, dev); } #endif diff --git a/fs/block_dev.c b/fs/block_dev.c index 606a5259f87f..c1c1b8c3fb99 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -854,24 +854,6 @@ static inline void bd_unlink_disk_holder(struct block_device *bdev) { } #endif -/* - * Tries to open block device by device number. 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. - */ -struct block_device *open_by_devnum(dev_t dev, fmode_t mode, void *holder) -{ - struct block_device *bdev = bdget(dev); - int err = -ENOMEM; - if (bdev) - err = blkdev_get(bdev, mode, holder); - return err ? ERR_PTR(err) : bdev; -} - -EXPORT_SYMBOL(open_by_devnum); - /** * flush_disk - invalidates all buffer-cache entries on a disk * @@ -1132,6 +1114,25 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) return ret; } +/** + * blkdev_get - open a block device + * @bdev: 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. + * + * On success, the reference count of @bdev is unchanged. On failure, + * @bdev is put. + * + * CONTEXT: + * Might sleep. + * + * RETURNS: + * 0 on success, -errno on failure. + */ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) { struct block_device *whole = NULL; @@ -1186,6 +1187,80 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) } EXPORT_SYMBOL(blkdev_get); +/** + * blkdev_get_by_path - open a block device by name + * @path: path to the block device to open + * @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. + * + * CONTEXT: + * Might sleep. + * + * RETURNS: + * Pointer to 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; + + err = blkdev_get(bdev, mode, holder); + if (err) + return ERR_PTR(err); + + return bdev; +} +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; @@ -1436,34 +1511,6 @@ fail: } EXPORT_SYMBOL(lookup_bdev); -/** - * open_bdev_exclusive - open a block device by name and set it up for use - * - * @path: special file representing the block device - * @mode: FMODE_... combination to pass be used - * @holder: owner for exclusion - * - * Open the blockdevice described by the special file at @path, claim it - * for the @holder. - */ -struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder) -{ - struct block_device *bdev; - int error; - - bdev = lookup_bdev(path); - if (IS_ERR(bdev)) - return bdev; - - error = blkdev_get(bdev, mode | FMODE_EXCL, holder); - if (error) - return ERR_PTR(error); - - return bdev; -} - -EXPORT_SYMBOL(open_bdev_exclusive); - int __invalidate_device(struct block_device *bdev) { struct super_block *sb = get_super(bdev); diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index f1b729d3b883..95324e9f9280 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -489,7 +489,7 @@ again: continue; if (device->bdev) { - blkdev_put(device->bdev, device->mode | FMODE_EXCL); + blkdev_put(device->bdev, device->mode); device->bdev = NULL; fs_devices->open_devices--; } @@ -523,7 +523,7 @@ static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices) list_for_each_entry(device, &fs_devices->devices, dev_list) { if (device->bdev) { - blkdev_put(device->bdev, device->mode | FMODE_EXCL); + blkdev_put(device->bdev, device->mode); fs_devices->open_devices--; } if (device->writeable) { @@ -580,13 +580,15 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices, int seeding = 1; int ret = 0; + flags |= FMODE_EXCL; + list_for_each_entry(device, head, dev_list) { if (device->bdev) continue; if (!device->name) continue; - bdev = open_bdev_exclusive(device->name, flags, holder); + bdev = blkdev_get_by_path(device->name, flags, holder); if (IS_ERR(bdev)) { printk(KERN_INFO "open %s failed\n", device->name); goto error; @@ -638,7 +640,7 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices, error_brelse: brelse(bh); error_close: - blkdev_put(bdev, flags | FMODE_EXCL); + blkdev_put(bdev, flags); error: continue; } @@ -684,7 +686,8 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, mutex_lock(&uuid_mutex); - bdev = open_bdev_exclusive(path, flags, holder); + flags |= FMODE_EXCL; + bdev = blkdev_get_by_path(path, flags, holder); if (IS_ERR(bdev)) { ret = PTR_ERR(bdev); @@ -716,7 +719,7 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, brelse(bh); error_close: - blkdev_put(bdev, flags | FMODE_EXCL); + blkdev_put(bdev, flags); error: mutex_unlock(&uuid_mutex); return ret; @@ -1179,8 +1182,8 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path) goto out; } } else { - bdev = open_bdev_exclusive(device_path, FMODE_READ, - root->fs_info->bdev_holder); + bdev = blkdev_get_by_path(device_path, FMODE_READ | FMODE_EXCL, + root->fs_info->bdev_holder); if (IS_ERR(bdev)) { ret = PTR_ERR(bdev); goto out; @@ -1244,7 +1247,7 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path) root->fs_info->fs_devices->latest_bdev = next_device->bdev; if (device->bdev) { - blkdev_put(device->bdev, device->mode | FMODE_EXCL); + blkdev_put(device->bdev, device->mode); device->bdev = NULL; device->fs_devices->open_devices--; } @@ -1439,7 +1442,8 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path) if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding) return -EINVAL; - bdev = open_bdev_exclusive(device_path, 0, root->fs_info->bdev_holder); + bdev = blkdev_get_by_path(device_path, FMODE_EXCL, + root->fs_info->bdev_holder); if (IS_ERR(bdev)) return PTR_ERR(bdev); diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 2b638b6e4eea..856e75770304 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -49,7 +49,7 @@ struct btrfs_device { struct block_device *bdev; - /* the mode sent to open_bdev_exclusive */ + /* the mode sent to blkdev_get */ fmode_t mode; char *name; diff --git a/fs/ext3/super.c b/fs/ext3/super.c index 23e7513dba9c..123720ba786d 100644 --- a/fs/ext3/super.c +++ b/fs/ext3/super.c @@ -347,7 +347,7 @@ static struct block_device *ext3_blkdev_get(dev_t dev, struct super_block *sb) struct block_device *bdev; char b[BDEVNAME_SIZE]; - bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb); + bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb); if (IS_ERR(bdev)) goto fail; return bdev; diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 5dd0b3e76fa8..bd63e6927219 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -647,7 +647,7 @@ static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb) struct block_device *bdev; char b[BDEVNAME_SIZE]; - bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb); + bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb); if (IS_ERR(bdev)) goto fail; return bdev; diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index c1f0763a022b..bc56ccf98ffd 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -1268,7 +1268,7 @@ static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags, { struct block_device *bdev; struct super_block *s; - fmode_t mode = FMODE_READ; + fmode_t mode = FMODE_READ | FMODE_EXCL; int error; struct gfs2_args args; struct gfs2_sbd *sdp; @@ -1276,7 +1276,7 @@ static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags, if (!(flags & MS_RDONLY)) mode |= FMODE_WRITE; - bdev = open_bdev_exclusive(dev_name, mode, fs_type); + bdev = blkdev_get_by_path(dev_name, mode, fs_type); if (IS_ERR(bdev)) return ERR_CAST(bdev); @@ -1298,7 +1298,7 @@ static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags, goto error_bdev; if (s->s_root) - blkdev_put(bdev, mode | FMODE_EXCL); + blkdev_put(bdev, mode); memset(&args, 0, sizeof(args)); args.ar_quota = GFS2_QUOTA_DEFAULT; @@ -1342,7 +1342,7 @@ error_super: deactivate_locked_super(s); return ERR_PTR(error); error_bdev: - blkdev_put(bdev, mode | FMODE_EXCL); + blkdev_put(bdev, mode); return ERR_PTR(error); } diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c index 5a290f22dcc3..278e3fb40b71 100644 --- a/fs/jfs/jfs_logmgr.c +++ b/fs/jfs/jfs_logmgr.c @@ -1120,8 +1120,8 @@ int lmLogOpen(struct super_block *sb) * file systems to log may have n-to-1 relationship; */ - bdev = open_by_devnum(sbi->logdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, - log); + bdev = blkdev_get_by_dev(sbi->logdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, + log); if (IS_ERR(bdev)) { rc = -PTR_ERR(bdev); goto free; diff --git a/fs/logfs/dev_bdev.c b/fs/logfs/dev_bdev.c index 734b9025858e..723bc5bca09a 100644 --- a/fs/logfs/dev_bdev.c +++ b/fs/logfs/dev_bdev.c @@ -325,7 +325,8 @@ int logfs_get_sb_bdev(struct logfs_super *p, struct file_system_type *type, { struct block_device *bdev; - bdev = open_bdev_exclusive(devname, FMODE_READ|FMODE_WRITE, type); + bdev = blkdev_get_by_path(devname, FMODE_READ|FMODE_WRITE|FMODE_EXCL, + type); if (IS_ERR(bdev)) return PTR_ERR(bdev); diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c index 756a6798d7c8..0030640e2d72 100644 --- a/fs/nilfs2/super.c +++ b/fs/nilfs2/super.c @@ -1147,14 +1147,14 @@ nilfs_mount(struct file_system_type *fs_type, int flags, { struct nilfs_super_data sd; struct super_block *s; - fmode_t mode = FMODE_READ; + fmode_t mode = FMODE_READ | FMODE_EXCL; struct dentry *root_dentry; int err, s_new = false; if (!(flags & MS_RDONLY)) mode |= FMODE_WRITE; - sd.bdev = open_bdev_exclusive(dev_name, mode, fs_type); + sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type); if (IS_ERR(sd.bdev)) return ERR_CAST(sd.bdev); @@ -1233,7 +1233,7 @@ nilfs_mount(struct file_system_type *fs_type, int flags, } if (!s_new) - blkdev_put(sd.bdev, mode | FMODE_EXCL); + blkdev_put(sd.bdev, mode); return root_dentry; @@ -1242,7 +1242,7 @@ nilfs_mount(struct file_system_type *fs_type, int flags, failed: if (!s_new) - blkdev_put(sd.bdev, mode | FMODE_EXCL); + blkdev_put(sd.bdev, mode); return ERR_PTR(err); } diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c index b488136f5ace..e2fce519c0f2 100644 --- a/fs/reiserfs/journal.c +++ b/fs/reiserfs/journal.c @@ -2585,7 +2585,8 @@ static int journal_init_dev(struct super_block *super, if ((!jdev_name || !jdev_name[0])) { if (jdev == super->s_dev) blkdev_mode &= ~FMODE_EXCL; - journal->j_dev_bd = open_by_devnum(jdev, blkdev_mode, journal); + journal->j_dev_bd = blkdev_get_by_dev(jdev, blkdev_mode, + journal); journal->j_dev_mode = blkdev_mode; if (IS_ERR(journal->j_dev_bd)) { result = PTR_ERR(journal->j_dev_bd); @@ -2601,8 +2602,7 @@ static int journal_init_dev(struct super_block *super, } journal->j_dev_mode = blkdev_mode; - journal->j_dev_bd = open_bdev_exclusive(jdev_name, - blkdev_mode, journal); + journal->j_dev_bd = blkdev_get_by_path(jdev_name, blkdev_mode, journal); if (IS_ERR(journal->j_dev_bd)) { result = PTR_ERR(journal->j_dev_bd); journal->j_dev_bd = NULL; diff --git a/fs/super.c b/fs/super.c index 22374bf0ba87..5d9a4497849a 100644 --- a/fs/super.c +++ b/fs/super.c @@ -766,13 +766,13 @@ struct dentry *mount_bdev(struct file_system_type *fs_type, { struct block_device *bdev; struct super_block *s; - fmode_t mode = FMODE_READ; + fmode_t mode = FMODE_READ | FMODE_EXCL; int error = 0; if (!(flags & MS_RDONLY)) mode |= FMODE_WRITE; - bdev = open_bdev_exclusive(dev_name, mode, fs_type); + bdev = blkdev_get_by_path(dev_name, mode, fs_type); if (IS_ERR(bdev)) return ERR_CAST(bdev); @@ -807,7 +807,7 @@ struct dentry *mount_bdev(struct file_system_type *fs_type, * holding an active reference. */ up_write(&s->s_umount); - blkdev_put(bdev, mode | FMODE_EXCL); + blkdev_put(bdev, mode); down_write(&s->s_umount); } else { char b[BDEVNAME_SIZE]; @@ -831,7 +831,7 @@ struct dentry *mount_bdev(struct file_system_type *fs_type, error_s: error = PTR_ERR(s); error_bdev: - blkdev_put(bdev, mode | FMODE_EXCL); + blkdev_put(bdev, mode); error: return ERR_PTR(error); } @@ -862,6 +862,7 @@ void kill_block_super(struct super_block *sb) bdev->bd_super = NULL; generic_shutdown_super(sb); sync_blockdev(bdev); + WARN_ON_ONCE(!(mode & FMODE_EXCL)); blkdev_put(bdev, mode | FMODE_EXCL); } diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c index a1a6e5ceea67..9209cd199c47 100644 --- a/fs/xfs/linux-2.6/xfs_super.c +++ b/fs/xfs/linux-2.6/xfs_super.c @@ -609,7 +609,8 @@ xfs_blkdev_get( { int error = 0; - *bdevp = open_bdev_exclusive(name, FMODE_READ|FMODE_WRITE, mp); + *bdevp = blkdev_get_by_path(name, FMODE_READ|FMODE_WRITE|FMODE_EXCL, + mp); if (IS_ERR(*bdevp)) { error = PTR_ERR(*bdevp); printk("XFS: Invalid device [%s], error=%d\n", name, error); diff --git a/include/linux/fs.h b/include/linux/fs.h index 1a033e8ebe4c..f48501563917 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2006,8 +2006,6 @@ extern struct block_device *bdgrab(struct block_device *bdev); extern void bd_set_size(struct block_device *, loff_t size); extern void bd_forget(struct inode *inode); extern void bdput(struct block_device *); -extern struct block_device *open_by_devnum(dev_t dev, fmode_t mode, - void *holder); extern void invalidate_bdev(struct block_device *); extern int sync_blockdev(struct block_device *bdev); extern struct super_block *freeze_bdev(struct block_device *); @@ -2039,6 +2037,10 @@ extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long); extern int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long); extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long); extern int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder); +extern struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, + void *holder); +extern struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, + void *holder); extern int blkdev_put(struct block_device *bdev, fmode_t mode); #ifdef CONFIG_SYSFS extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk); @@ -2083,7 +2085,6 @@ static inline void unregister_chrdev(unsigned int major, const char *name) extern const char *__bdevname(dev_t, char *buffer); extern const char *bdevname(struct block_device *bdev, char *buffer); extern struct block_device *lookup_bdev(const char *); -extern struct block_device *open_bdev_exclusive(const char *, fmode_t, void *); extern void blkdev_show(struct seq_file *,off_t); #else diff --git a/kernel/power/swap.c b/kernel/power/swap.c index 513a77f1a0b3..b019609d1b45 100644 --- a/kernel/power/swap.c +++ b/kernel/power/swap.c @@ -907,8 +907,8 @@ int swsusp_check(void) { int error; - hib_resume_bdev = open_by_devnum(swsusp_resume_device, - FMODE_READ, NULL); + hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device, + FMODE_READ, NULL); if (!IS_ERR(hib_resume_bdev)) { set_blocksize(hib_resume_bdev, PAGE_SIZE); clear_page(swsusp_header); -- cgit v1.2.3 From 77ea887e433ad8389d416826936c110fa7910f80 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 8 Dec 2010 20:57:37 +0100 Subject: implement in-kernel gendisk events handling Currently, media presence polling for removeable block devices is done from userland. There are several issues with this. * Polling is done by periodically opening the device. For SCSI devices, the command sequence generated by such action involves a few different commands including TEST_UNIT_READY. This behavior, while perfectly legal, is different from Windows which only issues single command, GET_EVENT_STATUS_NOTIFICATION. Unfortunately, some ATAPI devices lock up after being periodically queried such command sequences. * There is no reliable and unintrusive way for a userland program to tell whether the target device is safe for media presence polling. For example, polling for media presence during an on-going burning session can make it fail. The polling program can avoid this by opening the device with O_EXCL but then it risks making a valid exclusive user of the device fail w/ -EBUSY. * Userland polling is unnecessarily heavy and in-kernel implementation is lighter and better coordinated (workqueue, timer slack). This patch implements framework for in-kernel disk event handling, which includes media presence polling. * bdops->check_events() is added, which supercedes ->media_changed(). It should check whether there's any pending event and return if so. Currently, two events are defined - DISK_EVENT_MEDIA_CHANGE and DISK_EVENT_EJECT_REQUEST. ->check_events() is guaranteed not to be called parallelly. * gendisk->events and ->async_events are added. These should be initialized by block driver before passing the device to add_disk(). The former contains the mask of all supported events and the latter the mask of all events which the device can report without polling. /sys/block/*/events[_async] export these to userland. * Kernel parameter block.events_dfl_poll_msecs controls the system polling interval (default is 0 which means disable) and /sys/block/*/events_poll_msecs control polling intervals for individual devices (default is -1 meaning use system setting). Note that if a device can report all supported events asynchronously and its polling interval isn't explicitly set, the device won't be polled regardless of the system polling interval. * If a device is opened exclusively with write access, event checking is automatically disabled until all write exclusive accesses are released. * There are event 'clearing' events. For example, both of currently defined events are cleared after the device has been successfully opened. This information is passed to ->check_events() callback using @clearing argument as a hint. * Event checking is always performed from system_nrt_wq and timer slack is set to 25% for polling. * Nothing changes for drivers which implement ->media_changed() but not ->check_events(). Going forward, all drivers will be converted to ->check_events() and ->media_change() will be dropped. Signed-off-by: Tejun Heo Cc: Kay Sievers Cc: Jan Kara Signed-off-by: Jens Axboe --- block/genhd.c | 429 +++++++++++++++++++++++++++++++++++++++++++++++++ fs/block_dev.c | 41 ++++- include/linux/blkdev.h | 3 + include/linux/fs.h | 1 + include/linux/genhd.h | 18 ++- 5 files changed, 484 insertions(+), 8 deletions(-) (limited to 'fs/block_dev.c') diff --git a/block/genhd.c b/block/genhd.c index 2e5e4c0a1133..5465a824d489 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -18,6 +18,7 @@ #include #include #include +#include #include "blk.h" @@ -35,6 +36,10 @@ static DEFINE_IDR(ext_devt_idr); static struct device_type disk_type; +static void disk_add_events(struct gendisk *disk); +static void disk_del_events(struct gendisk *disk); +static void disk_release_events(struct gendisk *disk); + /** * disk_get_part - get partition * @disk: disk to look partition from @@ -609,6 +614,8 @@ void add_disk(struct gendisk *disk) retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj, "bdi"); WARN_ON(retval); + + disk_add_events(disk); } EXPORT_SYMBOL(add_disk); @@ -617,6 +624,8 @@ void del_gendisk(struct gendisk *disk) struct disk_part_iter piter; struct hd_struct *part; + disk_del_events(disk); + /* invalidate stuff */ disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE); @@ -1089,6 +1098,7 @@ static void disk_release(struct device *dev) { struct gendisk *disk = dev_to_disk(dev); + disk_release_events(disk); kfree(disk->random); disk_replace_part_tbl(disk, NULL); free_part_stats(&disk->part0); @@ -1350,3 +1360,422 @@ int invalidate_partition(struct gendisk *disk, int partno) } EXPORT_SYMBOL(invalidate_partition); + +/* + * Disk events - monitor disk events like media change and eject request. + */ +struct disk_events { + struct list_head node; /* all disk_event's */ + struct gendisk *disk; /* the associated disk */ + spinlock_t lock; + + int block; /* event blocking depth */ + unsigned int pending; /* events already sent out */ + unsigned int clearing; /* events being cleared */ + + long poll_msecs; /* interval, -1 for default */ + struct delayed_work dwork; +}; + +static const char *disk_events_strs[] = { + [ilog2(DISK_EVENT_MEDIA_CHANGE)] = "media_change", + [ilog2(DISK_EVENT_EJECT_REQUEST)] = "eject_request", +}; + +static char *disk_uevents[] = { + [ilog2(DISK_EVENT_MEDIA_CHANGE)] = "DISK_MEDIA_CHANGE=1", + [ilog2(DISK_EVENT_EJECT_REQUEST)] = "DISK_EJECT_REQUEST=1", +}; + +/* list of all disk_events */ +static DEFINE_MUTEX(disk_events_mutex); +static LIST_HEAD(disk_events); + +/* disable in-kernel polling by default */ +static unsigned long disk_events_dfl_poll_msecs = 0; + +static unsigned long disk_events_poll_jiffies(struct gendisk *disk) +{ + struct disk_events *ev = disk->ev; + long intv_msecs = 0; + + /* + * If device-specific poll interval is set, always use it. If + * the default is being used, poll iff there are events which + * can't be monitored asynchronously. + */ + if (ev->poll_msecs >= 0) + intv_msecs = ev->poll_msecs; + else if (disk->events & ~disk->async_events) + intv_msecs = disk_events_dfl_poll_msecs; + + return msecs_to_jiffies(intv_msecs); +} + +static void __disk_block_events(struct gendisk *disk, bool sync) +{ + struct disk_events *ev = disk->ev; + unsigned long flags; + bool cancel; + + spin_lock_irqsave(&ev->lock, flags); + cancel = !ev->block++; + spin_unlock_irqrestore(&ev->lock, flags); + + if (cancel) { + if (sync) + cancel_delayed_work_sync(&disk->ev->dwork); + else + cancel_delayed_work(&disk->ev->dwork); + } +} + +static void __disk_unblock_events(struct gendisk *disk, bool check_now) +{ + struct disk_events *ev = disk->ev; + unsigned long intv; + unsigned long flags; + + spin_lock_irqsave(&ev->lock, flags); + + if (WARN_ON_ONCE(ev->block <= 0)) + goto out_unlock; + + if (--ev->block) + goto out_unlock; + + /* + * Not exactly a latency critical operation, set poll timer + * slack to 25% and kick event check. + */ + intv = disk_events_poll_jiffies(disk); + set_timer_slack(&ev->dwork.timer, intv / 4); + if (check_now) + queue_delayed_work(system_nrt_wq, &ev->dwork, 0); + else if (intv) + queue_delayed_work(system_nrt_wq, &ev->dwork, intv); +out_unlock: + spin_unlock_irqrestore(&ev->lock, flags); +} + +/** + * disk_block_events - block and flush disk event checking + * @disk: disk to block events for + * + * On return from this function, it is guaranteed that event checking + * isn't in progress and won't happen until unblocked by + * disk_unblock_events(). Events blocking is counted and the actual + * unblocking happens after the matching number of unblocks are done. + * + * Note that this intentionally does not block event checking from + * disk_clear_events(). + * + * CONTEXT: + * Might sleep. + */ +void disk_block_events(struct gendisk *disk) +{ + if (disk->ev) + __disk_block_events(disk, true); +} + +/** + * disk_unblock_events - unblock disk event checking + * @disk: disk to unblock events for + * + * Undo disk_block_events(). When the block count reaches zero, it + * starts events polling if configured. + * + * CONTEXT: + * Don't care. Safe to call from irq context. + */ +void disk_unblock_events(struct gendisk *disk) +{ + if (disk->ev) + __disk_unblock_events(disk, true); +} + +/** + * disk_check_events - schedule immediate event checking + * @disk: disk to check events for + * + * Schedule immediate event checking on @disk if not blocked. + * + * CONTEXT: + * Don't care. Safe to call from irq context. + */ +void disk_check_events(struct gendisk *disk) +{ + if (disk->ev) { + __disk_block_events(disk, false); + __disk_unblock_events(disk, true); + } +} +EXPORT_SYMBOL_GPL(disk_check_events); + +/** + * disk_clear_events - synchronously check, clear and return pending events + * @disk: disk to fetch and clear events from + * @mask: mask of events to be fetched and clearted + * + * Disk events are synchronously checked and pending events in @mask + * are cleared and returned. This ignores the block count. + * + * CONTEXT: + * Might sleep. + */ +unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask) +{ + const struct block_device_operations *bdops = disk->fops; + struct disk_events *ev = disk->ev; + unsigned int pending; + + if (!ev) { + /* for drivers still using the old ->media_changed method */ + if ((mask & DISK_EVENT_MEDIA_CHANGE) && + bdops->media_changed && bdops->media_changed(disk)) + return DISK_EVENT_MEDIA_CHANGE; + return 0; + } + + /* tell the workfn about the events being cleared */ + spin_lock_irq(&ev->lock); + ev->clearing |= mask; + spin_unlock_irq(&ev->lock); + + /* uncondtionally schedule event check and wait for it to finish */ + __disk_block_events(disk, true); + queue_delayed_work(system_nrt_wq, &ev->dwork, 0); + flush_delayed_work(&ev->dwork); + __disk_unblock_events(disk, false); + + /* then, fetch and clear pending events */ + spin_lock_irq(&ev->lock); + WARN_ON_ONCE(ev->clearing & mask); /* cleared by workfn */ + pending = ev->pending & mask; + ev->pending &= ~mask; + spin_unlock_irq(&ev->lock); + + return pending; +} + +static void disk_events_workfn(struct work_struct *work) +{ + struct delayed_work *dwork = to_delayed_work(work); + struct disk_events *ev = container_of(dwork, struct disk_events, dwork); + struct gendisk *disk = ev->disk; + char *envp[ARRAY_SIZE(disk_uevents) + 1] = { }; + unsigned int clearing = ev->clearing; + unsigned int events; + unsigned long intv; + int nr_events = 0, i; + + /* check events */ + events = disk->fops->check_events(disk, clearing); + + /* accumulate pending events and schedule next poll if necessary */ + spin_lock_irq(&ev->lock); + + events &= ~ev->pending; + ev->pending |= events; + ev->clearing &= ~clearing; + + intv = disk_events_poll_jiffies(disk); + if (!ev->block && intv) + queue_delayed_work(system_nrt_wq, &ev->dwork, intv); + + spin_unlock_irq(&ev->lock); + + /* tell userland about new events */ + for (i = 0; i < ARRAY_SIZE(disk_uevents); i++) + if (events & (1 << i)) + envp[nr_events++] = disk_uevents[i]; + + if (nr_events) + kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp); +} + +/* + * A disk events enabled device has the following sysfs nodes under + * its /sys/block/X/ directory. + * + * events : list of all supported events + * events_async : list of events which can be detected w/o polling + * events_poll_msecs : polling interval, 0: disable, -1: system default + */ +static ssize_t __disk_events_show(unsigned int events, char *buf) +{ + const char *delim = ""; + ssize_t pos = 0; + int i; + + for (i = 0; i < ARRAY_SIZE(disk_events_strs); i++) + if (events & (1 << i)) { + pos += sprintf(buf + pos, "%s%s", + delim, disk_events_strs[i]); + delim = " "; + } + if (pos) + pos += sprintf(buf + pos, "\n"); + return pos; +} + +static ssize_t disk_events_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return __disk_events_show(disk->events, buf); +} + +static ssize_t disk_events_async_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return __disk_events_show(disk->async_events, buf); +} + +static ssize_t disk_events_poll_msecs_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%ld\n", disk->ev->poll_msecs); +} + +static ssize_t disk_events_poll_msecs_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct gendisk *disk = dev_to_disk(dev); + long intv; + + if (!count || !sscanf(buf, "%ld", &intv)) + return -EINVAL; + + if (intv < 0 && intv != -1) + return -EINVAL; + + __disk_block_events(disk, true); + disk->ev->poll_msecs = intv; + __disk_unblock_events(disk, true); + + return count; +} + +static const DEVICE_ATTR(events, S_IRUGO, disk_events_show, NULL); +static const DEVICE_ATTR(events_async, S_IRUGO, disk_events_async_show, NULL); +static const DEVICE_ATTR(events_poll_msecs, S_IRUGO|S_IWUSR, + disk_events_poll_msecs_show, + disk_events_poll_msecs_store); + +static const struct attribute *disk_events_attrs[] = { + &dev_attr_events.attr, + &dev_attr_events_async.attr, + &dev_attr_events_poll_msecs.attr, + NULL, +}; + +/* + * The default polling interval can be specified by the kernel + * parameter block.events_dfl_poll_msecs which defaults to 0 + * (disable). This can also be modified runtime by writing to + * /sys/module/block/events_dfl_poll_msecs. + */ +static int disk_events_set_dfl_poll_msecs(const char *val, + const struct kernel_param *kp) +{ + struct disk_events *ev; + int ret; + + ret = param_set_ulong(val, kp); + if (ret < 0) + return ret; + + mutex_lock(&disk_events_mutex); + + list_for_each_entry(ev, &disk_events, node) + disk_check_events(ev->disk); + + mutex_unlock(&disk_events_mutex); + + return 0; +} + +static const struct kernel_param_ops disk_events_dfl_poll_msecs_param_ops = { + .set = disk_events_set_dfl_poll_msecs, + .get = param_get_ulong, +}; + +#undef MODULE_PARAM_PREFIX +#define MODULE_PARAM_PREFIX "block." + +module_param_cb(events_dfl_poll_msecs, &disk_events_dfl_poll_msecs_param_ops, + &disk_events_dfl_poll_msecs, 0644); + +/* + * disk_{add|del|release}_events - initialize and destroy disk_events. + */ +static void disk_add_events(struct gendisk *disk) +{ + struct disk_events *ev; + + if (!disk->fops->check_events || !(disk->events | disk->async_events)) + return; + + ev = kzalloc(sizeof(*ev), GFP_KERNEL); + if (!ev) { + pr_warn("%s: failed to initialize events\n", disk->disk_name); + return; + } + + if (sysfs_create_files(&disk_to_dev(disk)->kobj, + disk_events_attrs) < 0) { + pr_warn("%s: failed to create sysfs files for events\n", + disk->disk_name); + kfree(ev); + return; + } + + disk->ev = ev; + + INIT_LIST_HEAD(&ev->node); + ev->disk = disk; + spin_lock_init(&ev->lock); + ev->block = 1; + ev->poll_msecs = -1; + INIT_DELAYED_WORK(&ev->dwork, disk_events_workfn); + + mutex_lock(&disk_events_mutex); + list_add_tail(&ev->node, &disk_events); + mutex_unlock(&disk_events_mutex); + + /* + * Block count is initialized to 1 and the following initial + * unblock kicks it into action. + */ + __disk_unblock_events(disk, true); +} + +static void disk_del_events(struct gendisk *disk) +{ + if (!disk->ev) + return; + + __disk_block_events(disk, true); + + mutex_lock(&disk_events_mutex); + list_del_init(&disk->ev->node); + mutex_unlock(&disk_events_mutex); + + sysfs_remove_files(&disk_to_dev(disk)->kobj, disk_events_attrs); +} + +static void disk_release_events(struct gendisk *disk) +{ + /* the block count should be 1 from disk_del_events() */ + WARN_ON_ONCE(disk->ev && disk->ev->block != 1); + kfree(disk->ev); +} diff --git a/fs/block_dev.c b/fs/block_dev.c index c1c1b8c3fb99..6017389711ee 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -948,10 +948,11 @@ int check_disk_change(struct block_device *bdev) { struct gendisk *disk = bdev->bd_disk; const struct block_device_operations *bdops = disk->fops; + unsigned int events; - if (!bdops->media_changed) - return 0; - if (!bdops->media_changed(bdev->bd_disk)) + events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE | + DISK_EVENT_EJECT_REQUEST); + if (!(events & DISK_EVENT_MEDIA_CHANGE)) return 0; flush_disk(bdev); @@ -1158,9 +1159,10 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) if (whole) { /* finish claiming */ + mutex_lock(&bdev->bd_mutex); spin_lock(&bdev_lock); - if (res == 0) { + if (!res) { BUG_ON(!bd_may_claim(bdev, whole, holder)); /* * Note that for a whole device bd_holders @@ -1180,6 +1182,20 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) wake_up_bit(&whole->bd_claiming, 0); spin_unlock(&bdev_lock); + + /* + * Block event polling for write claims. Any write + * holder makes the write_holder state stick until all + * are released. This is good enough and tracking + * individual writeable reference is too fragile given + * the way @mode is used in blkdev_get/put(). + */ + if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder) { + bdev->bd_write_holder = true; + disk_block_events(bdev->bd_disk); + } + + mutex_unlock(&bdev->bd_mutex); bdput(whole); } @@ -1353,12 +1369,23 @@ int blkdev_put(struct block_device *bdev, fmode_t mode) spin_unlock(&bdev_lock); - /* if this was the last claim, holder link should go too */ - if (bdev_free) + /* + * If this was the last claim, remove holder link and + * unblock evpoll if it was a write holder. + */ + if (bdev_free) { bd_unlink_disk_holder(bdev); + if (bdev->bd_write_holder) { + disk_unblock_events(bdev->bd_disk); + bdev->bd_write_holder = false; + } else + disk_check_events(bdev->bd_disk); + } mutex_unlock(&bdev->bd_mutex); - } + } else + disk_check_events(bdev->bd_disk); + return __blkdev_put(bdev, mode, 0); } EXPORT_SYMBOL(blkdev_put); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 83031bcf8366..05667e6989f1 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1251,6 +1251,9 @@ struct block_device_operations { int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long); int (*direct_access) (struct block_device *, sector_t, void **, unsigned long *); + unsigned int (*check_events) (struct gendisk *disk, + unsigned int clearing); + /* ->media_changed() is DEPRECATED, use ->check_events() instead */ int (*media_changed) (struct gendisk *); void (*unlock_native_capacity) (struct gendisk *); int (*revalidate_disk) (struct gendisk *); diff --git a/include/linux/fs.h b/include/linux/fs.h index f48501563917..997d22efdef0 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -662,6 +662,7 @@ struct block_device { void * bd_claiming; void * bd_holder; int bd_holders; + bool bd_write_holder; #ifdef CONFIG_SYSFS struct gendisk * bd_holder_disk; /* for sysfs slave linkng */ #endif diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 56e17ed24816..13893aa2ac9d 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -127,6 +127,11 @@ struct hd_struct { #define GENHD_FL_EXT_DEVT 64 /* allow extended devt */ #define GENHD_FL_NATIVE_CAPACITY 128 +enum { + DISK_EVENT_MEDIA_CHANGE = 1 << 0, /* media changed */ + DISK_EVENT_EJECT_REQUEST = 1 << 1, /* eject requested */ +}; + #define BLK_SCSI_MAX_CMDS (256) #define BLK_SCSI_CMD_PER_LONG (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8)) @@ -143,6 +148,8 @@ struct disk_part_tbl { struct hd_struct __rcu *part[]; }; +struct disk_events; + struct gendisk { /* major, first_minor and minors are input parameters only, * don't use directly. Use disk_devt() and disk_max_parts(). @@ -154,6 +161,10 @@ struct gendisk { char disk_name[DISK_NAME_LEN]; /* name of major driver */ char *(*devnode)(struct gendisk *gd, mode_t *mode); + + unsigned int events; /* supported events */ + unsigned int async_events; /* async events, subset of all */ + /* Array of pointers to partitions indexed by partno. * Protected with matching bdev lock but stat and other * non-critical accesses use RCU. Always access through @@ -171,8 +182,8 @@ struct gendisk { struct kobject *slave_dir; struct timer_rand_state *random; - atomic_t sync_io; /* RAID */ + struct disk_events *ev; #ifdef CONFIG_BLK_DEV_INTEGRITY struct blk_integrity *integrity; #endif @@ -405,6 +416,11 @@ static inline int get_disk_ro(struct gendisk *disk) return disk->part0.policy; } +extern void disk_block_events(struct gendisk *disk); +extern void disk_unblock_events(struct gendisk *disk); +extern void disk_check_events(struct gendisk *disk); +extern unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask); + /* drivers/char/random.c */ extern void add_disk_randomness(struct gendisk *disk); extern void rand_initialize_disk(struct gendisk *disk); -- cgit v1.2.3