X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=fs%2Fblock_dev.c;h=028d9fb9c2d536dafad7563e36874c0e8c934d91;hb=0928d68056fa25456830b1de9f0ee89bc37447cd;hp=573fc8e0b67a01b5f8ce799768ea241daeace02d;hpb=a41622eaa97e40c811fb7756f403c0d4caa65654;p=linux-2.6 diff --git a/fs/block_dev.c b/fs/block_dev.c index 573fc8e0b6..028d9fb9c2 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -131,9 +131,10 @@ blkdev_get_block(struct inode *inode, sector_t iblock, static int blkdev_get_blocks(struct inode *inode, sector_t iblock, - unsigned long max_blocks, struct buffer_head *bh, int create) + struct buffer_head *bh, int create) { sector_t end_block = max_block(I_BDEV(inode)); + unsigned long max_blocks = bh->b_size >> inode->i_blkbits; if ((iblock + max_blocks) > end_block) { max_blocks = end_block - iblock; @@ -234,7 +235,7 @@ static int block_fsync(struct file *filp, struct dentry *dentry, int datasync) */ static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); -static kmem_cache_t * bdev_cachep; +static kmem_cache_t * bdev_cachep __read_mostly; static struct inode *bdev_alloc_inode(struct super_block *sb) { @@ -265,6 +266,9 @@ static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags) mutex_init(&bdev->bd_mount_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); } } @@ -296,10 +300,10 @@ static struct super_operations bdev_sops = { .clear_inode = bdev_clear_inode, }; -static struct super_block *bd_get_sb(struct file_system_type *fs_type, - int flags, const char *dev_name, void *data) +static int bd_get_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data, struct vfsmount *mnt) { - return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576); + return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576, mnt); } static struct file_system_type bd_type = { @@ -308,7 +312,7 @@ static struct file_system_type bd_type = { .kill_sb = kill_anon_super, }; -static struct vfsmount *bd_mnt; +static struct vfsmount *bd_mnt __read_mostly; struct super_block *blockdev_superblock; void __init bdev_cache_init(void) @@ -410,21 +414,31 @@ EXPORT_SYMBOL(bdput); static struct block_device *bd_acquire(struct inode *inode) { struct block_device *bdev; + spin_lock(&bdev_lock); bdev = inode->i_bdev; - if (bdev && igrab(bdev->bd_inode)) { + if (bdev) { + atomic_inc(&bdev->bd_inode->i_count); spin_unlock(&bdev_lock); return bdev; } spin_unlock(&bdev_lock); + bdev = bdget(inode->i_rdev); if (bdev) { spin_lock(&bdev_lock); - if (inode->i_bdev) - __bd_forget(inode); - inode->i_bdev = bdev; - inode->i_mapping = bdev->bd_inode->i_mapping; - list_add(&inode->i_devices, &bdev->bd_inodes); + if (!inode->i_bdev) { + /* + * We take an additional bd_inode->i_count for inode, + * and it's released in clear_inode() of inode. + * So, we can access it via ->i_mapping always + * without igrab(). + */ + atomic_inc(&bdev->bd_inode->i_count); + inode->i_bdev = bdev; + inode->i_mapping = bdev->bd_inode->i_mapping; + list_add(&inode->i_devices, &bdev->bd_inodes); + } spin_unlock(&bdev_lock); } return bdev; @@ -434,10 +448,18 @@ static struct block_device *bd_acquire(struct inode *inode) void bd_forget(struct inode *inode) { + struct block_device *bdev = NULL; + spin_lock(&bdev_lock); - if (inode->i_bdev) + if (inode->i_bdev) { + if (inode->i_sb != blockdev_superblock) + bdev = inode->i_bdev; __bd_forget(inode); + } spin_unlock(&bdev_lock); + + if (bdev) + iput(bdev->bd_inode); } int bd_claim(struct block_device *bdev, void *holder) @@ -489,6 +511,300 @@ 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 struct kobject *bdev_get_kobj(struct block_device *bdev) +{ + if (bdev->bd_contains != bdev) + return kobject_get(&bdev->bd_part->kobj); + else + return kobject_get(&bdev->bd_disk->kobj); +} + +static struct kobject *bdev_get_holder(struct block_device *bdev) +{ + if (bdev->bd_contains != bdev) + return kobject_get(bdev->bd_part->holder_dir); + else + return kobject_get(bdev->bd_disk->holder_dir); +} + +static void add_symlink(struct kobject *from, struct kobject *to) +{ + if (!from || !to) + 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 = bdev_get_kobj(bdev); + if (!bo->sdev) + goto fail_put_hdev; + + bo->hdir = bdev_get_holder(bdev); + 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); +} + +/** + * add_bd_holder - create sysfs symlinks for bd_claim() relationship + * + * @bdev: block device to be bd_claimed + * @bo: preallocated and initialized by alloc_bd_holder() + * + * If there is no matching entry with @bo in @bdev->bd_holder_list, + * add @bo to the list, create symlinks. + * + * Returns 1 if @bo was added to the list. + * Returns 0 if @bo wasn't used by any reason and should be freed. + */ +static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo) +{ + struct bd_holder *tmp; + + if (!bo) + return 0; + + list_for_each_entry(tmp, &bdev->bd_holder_list, list) { + if (tmp->sdir == bo->sdir) { + tmp->count++; + return 0; + } + } + + if (!bd_holder_grab_dirs(bdev, bo)) + return 0; + + add_symlink(bo->sdir, bo->sdev); + add_symlink(bo->hdir, bo->hdev); + list_add_tail(&bo->list, &bdev->bd_holder_list); + return 1; +} + +/** + * 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 + * + * 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. + * + * Returns 0 on success. (same as bd_claim()) + * Returns errno on failure. + */ +static int bd_claim_by_kobject(struct block_device *bdev, void *holder, + struct kobject *kobj) +{ + int res; + struct bd_holder *bo; + + if (!kobj) + return -EINVAL; + + bo = alloc_bd_holder(kobj); + if (!bo) + return -ENOMEM; + + mutex_lock(&bdev->bd_mutex); + res = bd_claim(bdev, holder); + if (res || !add_bd_holder(bdev, bo)) + free_bd_holder(bo); + mutex_unlock(&bdev->bd_mutex); + + return res; +} + +/** + * 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) +{ + struct bd_holder *bo; + + if (!kobj) + return; + + mutex_lock(&bdev->bd_mutex); + bd_release(bdev); + if ((bo = del_bd_holder(bdev, kobj))) + free_bd_holder(bo); + mutex_unlock(&bdev->bd_mutex); +} + +/** + * 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) +{ + return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir)); +} +EXPORT_SYMBOL_GPL(bd_claim_by_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); +} +EXPORT_SYMBOL_GPL(bd_release_from_disk); +#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 @@ -789,7 +1105,7 @@ struct address_space_operations def_blk_aops = { .direct_IO = blkdev_direct_IO, }; -struct file_operations def_blk_fops = { +const struct file_operations def_blk_fops = { .open = blkdev_open, .release = blkdev_close, .llseek = block_llseek, @@ -806,6 +1122,8 @@ struct file_operations def_blk_fops = { .readv = generic_file_readv, .writev = generic_file_write_nolock, .sendfile = generic_file_sendfile, + .splice_read = generic_file_splice_read, + .splice_write = generic_file_splice_write, }; int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg)