From aff959c2840858d55d9ee155d555b3aa7e068b32 Mon Sep 17 00:00:00 2001 From: Chaitanya Kulkarni Date: Sun, 5 Sep 2021 19:26:01 -0700 Subject: nvme: update MAINTAINERS email address Update the MAINTAINERS file email address. Signed-off-by: Chaitanya Kulkarni Signed-off-by: Christoph Hellwig --- MAINTAINERS | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'MAINTAINERS') diff --git a/MAINTAINERS b/MAINTAINERS index 2f298429a5e9..64bf202c8c62 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -13367,7 +13367,7 @@ F: include/linux/nvme-fc.h NVM EXPRESS TARGET DRIVER M: Christoph Hellwig M: Sagi Grimberg -M: Chaitanya Kulkarni +M: Chaitanya Kulkarni L: linux-nvme@lists.infradead.org S: Supported W: http://git.infradead.org/nvme.git -- cgit v1.2.3-59-g8ed1b From 0dca4462ed0681649fdcd5700a6ddfbaa65fa178 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 7 Sep 2021 16:13:03 +0200 Subject: block: move fs/block_dev.c to block/bdev.c Move it together with the rest of the block layer. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20210907141303.1371844-3-hch@lst.de Signed-off-by: Jens Axboe --- Documentation/core-api/kernel-api.rst | 3 + Documentation/filesystems/api-summary.rst | 3 - MAINTAINERS | 1 - block/Makefile | 2 +- block/bdev.c | 1058 +++++++++++++++++++++++++++++ fs/Makefile | 2 +- fs/block_dev.c | 1058 ----------------------------- fs/internal.h | 2 +- 8 files changed, 1064 insertions(+), 1065 deletions(-) create mode 100644 block/bdev.c delete mode 100644 fs/block_dev.c (limited to 'MAINTAINERS') diff --git a/Documentation/core-api/kernel-api.rst b/Documentation/core-api/kernel-api.rst index 2a7444e3a4c2..2e7186805148 100644 --- a/Documentation/core-api/kernel-api.rst +++ b/Documentation/core-api/kernel-api.rst @@ -315,6 +315,9 @@ Block Devices .. kernel-doc:: block/genhd.c :export: +.. kernel-doc:: block/bdev.c + :export: + Char devices ============ diff --git a/Documentation/filesystems/api-summary.rst b/Documentation/filesystems/api-summary.rst index 7e5c04c98619..98db2ea5fa12 100644 --- a/Documentation/filesystems/api-summary.rst +++ b/Documentation/filesystems/api-summary.rst @@ -71,9 +71,6 @@ Other Functions .. kernel-doc:: fs/fs-writeback.c :export: -.. kernel-doc:: fs/block_dev.c - :export: - .. kernel-doc:: fs/anon_inodes.c :export: diff --git a/MAINTAINERS b/MAINTAINERS index 64bf202c8c62..2f0d830d549f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3300,7 +3300,6 @@ S: Maintained T: git git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git F: block/ F: drivers/block/ -F: fs/block_dev.c F: include/linux/blk* F: kernel/trace/blktrace.c F: lib/sbitmap.c diff --git a/block/Makefile b/block/Makefile index a4d8d149670b..c03b92d8a4bc 100644 --- a/block/Makefile +++ b/block/Makefile @@ -3,7 +3,7 @@ # Makefile for the kernel block layer # -obj-$(CONFIG_BLOCK) := fops.o bio.o elevator.o blk-core.o blk-sysfs.o \ +obj-$(CONFIG_BLOCK) := bdev.o fops.o bio.o elevator.o blk-core.o blk-sysfs.o \ blk-flush.o blk-settings.o blk-ioc.o blk-map.o \ blk-exec.o blk-merge.o blk-timeout.o \ blk-lib.o blk-mq.o blk-mq-tag.o blk-stat.o \ diff --git a/block/bdev.c b/block/bdev.c new file mode 100644 index 000000000000..cf2780cb44a7 --- /dev/null +++ b/block/bdev.c @@ -0,0 +1,1058 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright (C) 2001 Andrea Arcangeli SuSE + * Copyright (C) 2016 - 2020 Christoph Hellwig + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "../fs/internal.h" +#include "blk.h" + +struct bdev_inode { + struct block_device bdev; + struct inode vfs_inode; +}; + +static inline struct bdev_inode *BDEV_I(struct inode *inode) +{ + return container_of(inode, struct bdev_inode, vfs_inode); +} + +struct block_device *I_BDEV(struct inode *inode) +{ + return &BDEV_I(inode)->bdev; +} +EXPORT_SYMBOL(I_BDEV); + +static void bdev_write_inode(struct block_device *bdev) +{ + struct inode *inode = bdev->bd_inode; + int ret; + + spin_lock(&inode->i_lock); + while (inode->i_state & I_DIRTY) { + spin_unlock(&inode->i_lock); + ret = write_inode_now(inode, true); + if (ret) { + char name[BDEVNAME_SIZE]; + pr_warn_ratelimited("VFS: Dirty inode writeback failed " + "for block device %s (err=%d).\n", + bdevname(bdev, name), ret); + } + spin_lock(&inode->i_lock); + } + spin_unlock(&inode->i_lock); +} + +/* Kill _all_ buffers and pagecache , dirty or not.. */ +static void kill_bdev(struct block_device *bdev) +{ + struct address_space *mapping = bdev->bd_inode->i_mapping; + + if (mapping_empty(mapping)) + return; + + invalidate_bh_lrus(); + truncate_inode_pages(mapping, 0); +} + +/* Invalidate clean unused buffers and pagecache. */ +void invalidate_bdev(struct block_device *bdev) +{ + struct address_space *mapping = bdev->bd_inode->i_mapping; + + if (mapping->nrpages) { + invalidate_bh_lrus(); + lru_add_drain_all(); /* make sure all lru add caches are flushed */ + invalidate_mapping_pages(mapping, 0, -1); + } + /* 99% of the time, we don't need to flush the cleancache on the bdev. + * But, for the strange corners, lets be cautious + */ + cleancache_invalidate_inode(mapping); +} +EXPORT_SYMBOL(invalidate_bdev); + +/* + * Drop all buffers & page cache for given bdev range. This function bails + * with error if bdev has other exclusive owner (such as filesystem). + */ +int truncate_bdev_range(struct block_device *bdev, fmode_t mode, + loff_t lstart, loff_t lend) +{ + /* + * If we don't hold exclusive handle for the device, upgrade to it + * while we discard the buffer cache to avoid discarding buffers + * under live filesystem. + */ + if (!(mode & FMODE_EXCL)) { + int err = bd_prepare_to_claim(bdev, truncate_bdev_range); + if (err) + goto invalidate; + } + + truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend); + if (!(mode & FMODE_EXCL)) + bd_abort_claiming(bdev, truncate_bdev_range); + return 0; + +invalidate: + /* + * Someone else has handle exclusively open. Try invalidating instead. + * The 'end' argument is inclusive so the rounding is safe. + */ + return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping, + lstart >> PAGE_SHIFT, + lend >> PAGE_SHIFT); +} + +static void set_init_blocksize(struct block_device *bdev) +{ + unsigned int bsize = bdev_logical_block_size(bdev); + loff_t size = i_size_read(bdev->bd_inode); + + while (bsize < PAGE_SIZE) { + if (size & bsize) + break; + bsize <<= 1; + } + bdev->bd_inode->i_blkbits = blksize_bits(bsize); +} + +int set_blocksize(struct block_device *bdev, int size) +{ + /* Size must be a power of two, and between 512 and PAGE_SIZE */ + if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) + return -EINVAL; + + /* Size cannot be smaller than the size supported by the device */ + if (size < bdev_logical_block_size(bdev)) + return -EINVAL; + + /* Don't change the size if it is same as current */ + if (bdev->bd_inode->i_blkbits != blksize_bits(size)) { + sync_blockdev(bdev); + bdev->bd_inode->i_blkbits = blksize_bits(size); + kill_bdev(bdev); + } + return 0; +} + +EXPORT_SYMBOL(set_blocksize); + +int sb_set_blocksize(struct super_block *sb, int size) +{ + if (set_blocksize(sb->s_bdev, size)) + return 0; + /* If we get here, we know size is power of two + * and it's value is between 512 and PAGE_SIZE */ + sb->s_blocksize = size; + sb->s_blocksize_bits = blksize_bits(size); + return sb->s_blocksize; +} + +EXPORT_SYMBOL(sb_set_blocksize); + +int sb_min_blocksize(struct super_block *sb, int size) +{ + int minsize = bdev_logical_block_size(sb->s_bdev); + if (size < minsize) + size = minsize; + return sb_set_blocksize(sb, size); +} + +EXPORT_SYMBOL(sb_min_blocksize); + +int __sync_blockdev(struct block_device *bdev, int wait) +{ + if (!bdev) + return 0; + if (!wait) + return filemap_flush(bdev->bd_inode->i_mapping); + return filemap_write_and_wait(bdev->bd_inode->i_mapping); +} + +/* + * Write out and wait upon all the dirty data associated with a block + * device via its mapping. Does not take the superblock lock. + */ +int sync_blockdev(struct block_device *bdev) +{ + return __sync_blockdev(bdev, 1); +} +EXPORT_SYMBOL(sync_blockdev); + +/* + * Write out and wait upon all dirty data associated with this + * device. Filesystem data as well as the underlying block + * device. Takes the superblock lock. + */ +int fsync_bdev(struct block_device *bdev) +{ + struct super_block *sb = get_super(bdev); + if (sb) { + int res = sync_filesystem(sb); + drop_super(sb); + return res; + } + return sync_blockdev(bdev); +} +EXPORT_SYMBOL(fsync_bdev); + +/** + * freeze_bdev -- lock a filesystem and force it into a consistent state + * @bdev: blockdevice to lock + * + * If a superblock is found on this device, we take the s_umount semaphore + * on it to make sure nobody unmounts until the snapshot creation is done. + * The reference counter (bd_fsfreeze_count) guarantees that only the last + * unfreeze process can unfreeze the frozen filesystem actually when multiple + * freeze requests arrive simultaneously. It counts up in freeze_bdev() and + * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze + * actually. + */ +int freeze_bdev(struct block_device *bdev) +{ + struct super_block *sb; + int error = 0; + + mutex_lock(&bdev->bd_fsfreeze_mutex); + if (++bdev->bd_fsfreeze_count > 1) + goto done; + + sb = get_active_super(bdev); + if (!sb) + goto sync; + if (sb->s_op->freeze_super) + error = sb->s_op->freeze_super(sb); + else + error = freeze_super(sb); + deactivate_super(sb); + + if (error) { + bdev->bd_fsfreeze_count--; + goto done; + } + bdev->bd_fsfreeze_sb = sb; + +sync: + sync_blockdev(bdev); +done: + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return error; +} +EXPORT_SYMBOL(freeze_bdev); + +/** + * thaw_bdev -- unlock filesystem + * @bdev: blockdevice to unlock + * + * Unlocks the filesystem and marks it writeable again after freeze_bdev(). + */ +int thaw_bdev(struct block_device *bdev) +{ + struct super_block *sb; + int error = -EINVAL; + + mutex_lock(&bdev->bd_fsfreeze_mutex); + if (!bdev->bd_fsfreeze_count) + goto out; + + error = 0; + if (--bdev->bd_fsfreeze_count > 0) + goto out; + + sb = bdev->bd_fsfreeze_sb; + if (!sb) + goto out; + + if (sb->s_op->thaw_super) + error = sb->s_op->thaw_super(sb); + else + error = thaw_super(sb); + if (error) + bdev->bd_fsfreeze_count++; + else + bdev->bd_fsfreeze_sb = NULL; +out: + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return error; +} +EXPORT_SYMBOL(thaw_bdev); + +/** + * bdev_read_page() - Start reading a page from a block device + * @bdev: The device to read the page from + * @sector: The offset on the device to read the page to (need not be aligned) + * @page: The page to read + * + * On entry, the page should be locked. It will be unlocked when the page + * has been read. If the block driver implements rw_page synchronously, + * that will be true on exit from this function, but it need not be. + * + * Errors returned by this function are usually "soft", eg out of memory, or + * queue full; callers should try a different route to read this page rather + * than propagate an error back up the stack. + * + * Return: negative errno if an error occurs, 0 if submission was successful. + */ +int bdev_read_page(struct block_device *bdev, sector_t sector, + struct page *page) +{ + const struct block_device_operations *ops = bdev->bd_disk->fops; + int result = -EOPNOTSUPP; + + if (!ops->rw_page || bdev_get_integrity(bdev)) + return result; + + result = blk_queue_enter(bdev->bd_disk->queue, 0); + if (result) + return result; + result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, + REQ_OP_READ); + blk_queue_exit(bdev->bd_disk->queue); + return result; +} + +/** + * bdev_write_page() - Start writing a page to a block device + * @bdev: The device to write the page to + * @sector: The offset on the device to write the page to (need not be aligned) + * @page: The page to write + * @wbc: The writeback_control for the write + * + * On entry, the page should be locked and not currently under writeback. + * On exit, if the write started successfully, the page will be unlocked and + * under writeback. If the write failed already (eg the driver failed to + * queue the page to the device), the page will still be locked. If the + * caller is a ->writepage implementation, it will need to unlock the page. + * + * Errors returned by this function are usually "soft", eg out of memory, or + * queue full; callers should try a different route to write this page rather + * than propagate an error back up the stack. + * + * Return: negative errno if an error occurs, 0 if submission was successful. + */ +int bdev_write_page(struct block_device *bdev, sector_t sector, + struct page *page, struct writeback_control *wbc) +{ + int result; + const struct block_device_operations *ops = bdev->bd_disk->fops; + + if (!ops->rw_page || bdev_get_integrity(bdev)) + return -EOPNOTSUPP; + result = blk_queue_enter(bdev->bd_disk->queue, 0); + if (result) + return result; + + set_page_writeback(page); + result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, + REQ_OP_WRITE); + if (result) { + end_page_writeback(page); + } else { + clean_page_buffers(page); + unlock_page(page); + } + blk_queue_exit(bdev->bd_disk->queue); + return result; +} + +/* + * pseudo-fs + */ + +static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); +static struct kmem_cache * bdev_cachep __read_mostly; + +static struct inode *bdev_alloc_inode(struct super_block *sb) +{ + struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL); + + if (!ei) + return NULL; + memset(&ei->bdev, 0, sizeof(ei->bdev)); + return &ei->vfs_inode; +} + +static void bdev_free_inode(struct inode *inode) +{ + struct block_device *bdev = I_BDEV(inode); + + free_percpu(bdev->bd_stats); + kfree(bdev->bd_meta_info); + + if (!bdev_is_partition(bdev)) { + if (bdev->bd_disk && bdev->bd_disk->bdi) + bdi_put(bdev->bd_disk->bdi); + kfree(bdev->bd_disk); + } + + if (MAJOR(bdev->bd_dev) == BLOCK_EXT_MAJOR) + blk_free_ext_minor(MINOR(bdev->bd_dev)); + + kmem_cache_free(bdev_cachep, BDEV_I(inode)); +} + +static void init_once(void *data) +{ + struct bdev_inode *ei = data; + + inode_init_once(&ei->vfs_inode); +} + +static void bdev_evict_inode(struct inode *inode) +{ + truncate_inode_pages_final(&inode->i_data); + invalidate_inode_buffers(inode); /* is it needed here? */ + clear_inode(inode); +} + +static const struct super_operations bdev_sops = { + .statfs = simple_statfs, + .alloc_inode = bdev_alloc_inode, + .free_inode = bdev_free_inode, + .drop_inode = generic_delete_inode, + .evict_inode = bdev_evict_inode, +}; + +static int bd_init_fs_context(struct fs_context *fc) +{ + struct pseudo_fs_context *ctx = init_pseudo(fc, BDEVFS_MAGIC); + if (!ctx) + return -ENOMEM; + fc->s_iflags |= SB_I_CGROUPWB; + ctx->ops = &bdev_sops; + return 0; +} + +static struct file_system_type bd_type = { + .name = "bdev", + .init_fs_context = bd_init_fs_context, + .kill_sb = kill_anon_super, +}; + +struct super_block *blockdev_superblock __read_mostly; +EXPORT_SYMBOL_GPL(blockdev_superblock); + +void __init bdev_cache_init(void) +{ + int err; + static struct vfsmount *bd_mnt; + + bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), + 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| + SLAB_MEM_SPREAD|SLAB_ACCOUNT|SLAB_PANIC), + init_once); + err = register_filesystem(&bd_type); + if (err) + panic("Cannot register bdev pseudo-fs"); + bd_mnt = kern_mount(&bd_type); + if (IS_ERR(bd_mnt)) + panic("Cannot create bdev pseudo-fs"); + blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ +} + +struct block_device *bdev_alloc(struct gendisk *disk, u8 partno) +{ + struct block_device *bdev; + struct inode *inode; + + inode = new_inode(blockdev_superblock); + if (!inode) + return NULL; + inode->i_mode = S_IFBLK; + inode->i_rdev = 0; + inode->i_data.a_ops = &def_blk_aops; + mapping_set_gfp_mask(&inode->i_data, GFP_USER); + + bdev = I_BDEV(inode); + mutex_init(&bdev->bd_fsfreeze_mutex); + spin_lock_init(&bdev->bd_size_lock); + bdev->bd_disk = disk; + bdev->bd_partno = partno; + bdev->bd_inode = inode; + bdev->bd_stats = alloc_percpu(struct disk_stats); + if (!bdev->bd_stats) { + iput(inode); + return NULL; + } + return bdev; +} + +void bdev_add(struct block_device *bdev, dev_t dev) +{ + bdev->bd_dev = dev; + bdev->bd_inode->i_rdev = dev; + bdev->bd_inode->i_ino = dev; + insert_inode_hash(bdev->bd_inode); +} + +long nr_blockdev_pages(void) +{ + struct inode *inode; + long ret = 0; + + spin_lock(&blockdev_superblock->s_inode_list_lock); + list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) + ret += inode->i_mapping->nrpages; + spin_unlock(&blockdev_superblock->s_inode_list_lock); + + return ret; +} + +/** + * bd_may_claim - test whether a block device can be claimed + * @bdev: block device of interest + * @whole: whole block device containing @bdev, may equal @bdev + * @holder: holder trying to claim @bdev + * + * Test whether @bdev can be claimed by @holder. + * + * CONTEXT: + * spin_lock(&bdev_lock). + * + * RETURNS: + * %true if @bdev can be claimed, %false otherwise. + */ +static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, + void *holder) +{ + if (bdev->bd_holder == holder) + return true; /* already a holder */ + else if (bdev->bd_holder != NULL) + return false; /* held by someone else */ + else if (whole == bdev) + return true; /* is a whole device which isn't held */ + + 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 */ + else + return true; /* is a partition of an un-held device */ +} + +/** + * bd_prepare_to_claim - claim a block device + * @bdev: block device of interest + * @holder: holder trying to claim @bdev + * + * Claim @bdev. This function fails if @bdev is already claimed by another + * holder and waits if another claiming is in progress. return, the caller + * has ownership of bd_claiming and bd_holder[s]. + * + * RETURNS: + * 0 if @bdev can be claimed, -EBUSY otherwise. + */ +int bd_prepare_to_claim(struct block_device *bdev, void *holder) +{ + struct block_device *whole = bdev_whole(bdev); + + if (WARN_ON_ONCE(!holder)) + return -EINVAL; +retry: + spin_lock(&bdev_lock); + /* if someone else claimed, fail */ + if (!bd_may_claim(bdev, whole, holder)) { + spin_unlock(&bdev_lock); + return -EBUSY; + } + + /* if claiming is already in progress, wait for it to finish */ + if (whole->bd_claiming) { + wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0); + DEFINE_WAIT(wait); + + prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); + spin_unlock(&bdev_lock); + schedule(); + finish_wait(wq, &wait); + goto retry; + } + + /* yay, all mine */ + whole->bd_claiming = holder; + spin_unlock(&bdev_lock); + return 0; +} +EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */ + +static void bd_clear_claiming(struct block_device *whole, void *holder) +{ + lockdep_assert_held(&bdev_lock); + /* tell others that we're done */ + BUG_ON(whole->bd_claiming != holder); + whole->bd_claiming = NULL; + wake_up_bit(&whole->bd_claiming, 0); +} + +/** + * bd_finish_claiming - finish claiming of a block device + * @bdev: block device of interest + * @holder: holder that has claimed @bdev + * + * Finish exclusive open of a block device. Mark the device as exlusively + * open by the holder and wake up all waiters for exclusive open to finish. + */ +static void bd_finish_claiming(struct block_device *bdev, void *holder) +{ + struct block_device *whole = bdev_whole(bdev); + + spin_lock(&bdev_lock); + 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; + bd_clear_claiming(whole, holder); + spin_unlock(&bdev_lock); +} + +/** + * bd_abort_claiming - abort claiming of a block device + * @bdev: block device of interest + * @holder: holder that has claimed @bdev + * + * Abort claiming of a block device when the exclusive open failed. This can be + * also used when exclusive open is not actually desired and we just needed + * to block other exclusive openers for a while. + */ +void bd_abort_claiming(struct block_device *bdev, void *holder) +{ + spin_lock(&bdev_lock); + bd_clear_claiming(bdev_whole(bdev), holder); + spin_unlock(&bdev_lock); +} +EXPORT_SYMBOL(bd_abort_claiming); + +static void blkdev_flush_mapping(struct block_device *bdev) +{ + WARN_ON_ONCE(bdev->bd_holders); + sync_blockdev(bdev); + kill_bdev(bdev); + bdev_write_inode(bdev); +} + +static int blkdev_get_whole(struct block_device *bdev, fmode_t mode) +{ + struct gendisk *disk = bdev->bd_disk; + int ret = 0; + + if (disk->fops->open) { + ret = disk->fops->open(bdev, mode); + if (ret) { + /* avoid ghost partitions on a removed medium */ + if (ret == -ENOMEDIUM && + test_bit(GD_NEED_PART_SCAN, &disk->state)) + bdev_disk_changed(disk, true); + return ret; + } + } + + if (!bdev->bd_openers) + set_init_blocksize(bdev); + if (test_bit(GD_NEED_PART_SCAN, &disk->state)) + bdev_disk_changed(disk, false); + bdev->bd_openers++; + return 0;; +} + +static void blkdev_put_whole(struct block_device *bdev, fmode_t mode) +{ + if (!--bdev->bd_openers) + blkdev_flush_mapping(bdev); + if (bdev->bd_disk->fops->release) + bdev->bd_disk->fops->release(bdev->bd_disk, mode); +} + +static int blkdev_get_part(struct block_device *part, fmode_t mode) +{ + struct gendisk *disk = part->bd_disk; + int ret; + + if (part->bd_openers) + goto done; + + ret = blkdev_get_whole(bdev_whole(part), mode); + if (ret) + return ret; + + ret = -ENXIO; + if (!bdev_nr_sectors(part)) + goto out_blkdev_put; + + disk->open_partitions++; + set_init_blocksize(part); +done: + part->bd_openers++; + return 0; + +out_blkdev_put: + blkdev_put_whole(bdev_whole(part), mode); + return ret; +} + +static void blkdev_put_part(struct block_device *part, fmode_t mode) +{ + struct block_device *whole = bdev_whole(part); + + if (--part->bd_openers) + return; + blkdev_flush_mapping(part); + whole->bd_disk->open_partitions--; + blkdev_put_whole(whole, mode); +} + +struct block_device *blkdev_get_no_open(dev_t dev) +{ + struct block_device *bdev; + struct inode *inode; + + inode = ilookup(blockdev_superblock, dev); + if (!inode) { + blk_request_module(dev); + inode = ilookup(blockdev_superblock, dev); + if (!inode) + return NULL; + } + + /* switch from the inode reference to a device mode one: */ + bdev = &BDEV_I(inode)->bdev; + if (!kobject_get_unless_zero(&bdev->bd_device.kobj)) + bdev = NULL; + iput(inode); + + if (!bdev) + return NULL; + if ((bdev->bd_disk->flags & GENHD_FL_HIDDEN) || + !try_module_get(bdev->bd_disk->fops->owner)) { + put_device(&bdev->bd_device); + return NULL; + } + + return bdev; +} + +void blkdev_put_no_open(struct block_device *bdev) +{ + module_put(bdev->bd_disk->fops->owner); + put_device(&bdev->bd_device); +} + +/** + * 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 block device described by device number @dev. If @mode includes + * %FMODE_EXCL, the block device is opened with exclusive access. Specifying + * %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may nest for + * the same @holder. + * + * Use this interface ONLY if you really do not have anything better - i.e. when + * you are behind a truly sucky interface and all you are given is a device + * number. Everything else should use blkdev_get_by_path(). + * + * CONTEXT: + * Might sleep. + * + * RETURNS: + * Reference to the block_device on success, ERR_PTR(-errno) on failure. + */ +struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) +{ + bool unblock_events = true; + struct block_device *bdev; + struct gendisk *disk; + int ret; + + ret = devcgroup_check_permission(DEVCG_DEV_BLOCK, + MAJOR(dev), MINOR(dev), + ((mode & FMODE_READ) ? DEVCG_ACC_READ : 0) | + ((mode & FMODE_WRITE) ? DEVCG_ACC_WRITE : 0)); + if (ret) + return ERR_PTR(ret); + + bdev = blkdev_get_no_open(dev); + if (!bdev) + return ERR_PTR(-ENXIO); + disk = bdev->bd_disk; + + if (mode & FMODE_EXCL) { + ret = bd_prepare_to_claim(bdev, holder); + if (ret) + goto put_blkdev; + } + + disk_block_events(disk); + + mutex_lock(&disk->open_mutex); + ret = -ENXIO; + if (!disk_live(disk)) + goto abort_claiming; + if (bdev_is_partition(bdev)) + ret = blkdev_get_part(bdev, mode); + else + ret = blkdev_get_whole(bdev, mode); + if (ret) + goto abort_claiming; + if (mode & FMODE_EXCL) { + bd_finish_claiming(bdev, holder); + + /* + * Block event polling for write claims if requested. 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 ((mode & FMODE_WRITE) && !bdev->bd_write_holder && + (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) { + bdev->bd_write_holder = true; + unblock_events = false; + } + } + mutex_unlock(&disk->open_mutex); + + if (unblock_events) + disk_unblock_events(disk); + return bdev; + +abort_claiming: + if (mode & FMODE_EXCL) + bd_abort_claiming(bdev, holder); + mutex_unlock(&disk->open_mutex); + disk_unblock_events(disk); +put_blkdev: + blkdev_put_no_open(bdev); + return ERR_PTR(ret); +} +EXPORT_SYMBOL(blkdev_get_by_dev); + +/** + * 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 block device described by the device file at @path. If @mode + * includes %FMODE_EXCL, the block device is opened with exclusive access. + * Specifying %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may + * nest for the same @holder. + * + * CONTEXT: + * Might sleep. + * + * RETURNS: + * Reference to the block_device on success, ERR_PTR(-errno) on failure. + */ +struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, + void *holder) +{ + struct block_device *bdev; + dev_t dev; + int error; + + error = lookup_bdev(path, &dev); + if (error) + return ERR_PTR(error); + + bdev = blkdev_get_by_dev(dev, mode, holder); + if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) { + blkdev_put(bdev, mode); + return ERR_PTR(-EACCES); + } + + return bdev; +} +EXPORT_SYMBOL(blkdev_get_by_path); + +void blkdev_put(struct block_device *bdev, fmode_t mode) +{ + struct gendisk *disk = bdev->bd_disk; + + /* + * Sync early if it looks like we're the last one. If someone else + * opens the block device between now and the decrement of bd_openers + * then we did a sync that we didn't need to, but that's not the end + * of the world and we want to avoid long (could be several minute) + * syncs while holding the mutex. + */ + if (bdev->bd_openers == 1) + sync_blockdev(bdev); + + mutex_lock(&disk->open_mutex); + if (mode & FMODE_EXCL) { + struct block_device *whole = bdev_whole(bdev); + bool bdev_free; + + /* + * Release a claim on the device. The holder fields + * are protected with bdev_lock. open_mutex is to + * synchronize disk_holder unlinking. + */ + spin_lock(&bdev_lock); + + WARN_ON_ONCE(--bdev->bd_holders < 0); + WARN_ON_ONCE(--whole->bd_holders < 0); + + if ((bdev_free = !bdev->bd_holders)) + bdev->bd_holder = NULL; + if (!whole->bd_holders) + whole->bd_holder = NULL; + + spin_unlock(&bdev_lock); + + /* + * If this was the last claim, remove holder link and + * unblock evpoll if it was a write holder. + */ + if (bdev_free && bdev->bd_write_holder) { + disk_unblock_events(disk); + bdev->bd_write_holder = false; + } + } + + /* + * Trigger event checking and tell drivers to flush MEDIA_CHANGE + * event. This is to ensure detection of media removal commanded + * from userland - e.g. eject(1). + */ + disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE); + + if (bdev_is_partition(bdev)) + blkdev_put_part(bdev, mode); + else + blkdev_put_whole(bdev, mode); + mutex_unlock(&disk->open_mutex); + + blkdev_put_no_open(bdev); +} +EXPORT_SYMBOL(blkdev_put); + +/** + * lookup_bdev - lookup a struct block_device by name + * @pathname: special file representing the block device + * @dev: return value of the block device's dev_t + * + * Get a reference to the blockdevice at @pathname in the current + * namespace if possible and return it. Return ERR_PTR(error) + * otherwise. + */ +int lookup_bdev(const char *pathname, dev_t *dev) +{ + struct inode *inode; + struct path path; + int error; + + if (!pathname || !*pathname) + return -EINVAL; + + error = kern_path(pathname, LOOKUP_FOLLOW, &path); + if (error) + return error; + + inode = d_backing_inode(path.dentry); + error = -ENOTBLK; + if (!S_ISBLK(inode->i_mode)) + goto out_path_put; + error = -EACCES; + if (!may_open_dev(&path)) + goto out_path_put; + + *dev = inode->i_rdev; + error = 0; +out_path_put: + path_put(&path); + return error; +} +EXPORT_SYMBOL(lookup_bdev); + +int __invalidate_device(struct block_device *bdev, bool kill_dirty) +{ + struct super_block *sb = get_super(bdev); + int res = 0; + + if (sb) { + /* + * no need to lock the super, get_super holds the + * read mutex so the filesystem cannot go away + * under us (->put_super runs with the write lock + * hold). + */ + shrink_dcache_sb(sb); + res = invalidate_inodes(sb, kill_dirty); + drop_super(sb); + } + invalidate_bdev(bdev); + return res; +} +EXPORT_SYMBOL(__invalidate_device); + +void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg) +{ + struct inode *inode, *old_inode = NULL; + + spin_lock(&blockdev_superblock->s_inode_list_lock); + list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) { + struct address_space *mapping = inode->i_mapping; + struct block_device *bdev; + + spin_lock(&inode->i_lock); + if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) || + mapping->nrpages == 0) { + spin_unlock(&inode->i_lock); + continue; + } + __iget(inode); + spin_unlock(&inode->i_lock); + spin_unlock(&blockdev_superblock->s_inode_list_lock); + /* + * We hold a reference to 'inode' so it couldn't have been + * removed from s_inodes list while we dropped the + * s_inode_list_lock We cannot iput the inode now as we can + * be holding the last reference and we cannot iput it under + * s_inode_list_lock. So we keep the reference and iput it + * later. + */ + iput(old_inode); + old_inode = inode; + bdev = I_BDEV(inode); + + mutex_lock(&bdev->bd_disk->open_mutex); + if (bdev->bd_openers) + func(bdev, arg); + mutex_unlock(&bdev->bd_disk->open_mutex); + + spin_lock(&blockdev_superblock->s_inode_list_lock); + } + spin_unlock(&blockdev_superblock->s_inode_list_lock); + iput(old_inode); +} diff --git a/fs/Makefile b/fs/Makefile index 354e2ba3ee67..a1b89b1dc8fc 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -17,7 +17,7 @@ obj-y := open.o read_write.o file_table.o super.o \ kernel_read_file.o remap_range.o ifeq ($(CONFIG_BLOCK),y) -obj-y += buffer.o block_dev.o direct-io.o mpage.o +obj-y += buffer.o direct-io.o mpage.o else obj-y += no-block.o endif diff --git a/fs/block_dev.c b/fs/block_dev.c deleted file mode 100644 index 84c97e276047..000000000000 --- a/fs/block_dev.c +++ /dev/null @@ -1,1058 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -/* - * Copyright (C) 1991, 1992 Linus Torvalds - * Copyright (C) 2001 Andrea Arcangeli SuSE - * Copyright (C) 2016 - 2020 Christoph Hellwig - */ - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include "internal.h" -#include "../block/blk.h" - -struct bdev_inode { - struct block_device bdev; - struct inode vfs_inode; -}; - -static inline struct bdev_inode *BDEV_I(struct inode *inode) -{ - return container_of(inode, struct bdev_inode, vfs_inode); -} - -struct block_device *I_BDEV(struct inode *inode) -{ - return &BDEV_I(inode)->bdev; -} -EXPORT_SYMBOL(I_BDEV); - -static void bdev_write_inode(struct block_device *bdev) -{ - struct inode *inode = bdev->bd_inode; - int ret; - - spin_lock(&inode->i_lock); - while (inode->i_state & I_DIRTY) { - spin_unlock(&inode->i_lock); - ret = write_inode_now(inode, true); - if (ret) { - char name[BDEVNAME_SIZE]; - pr_warn_ratelimited("VFS: Dirty inode writeback failed " - "for block device %s (err=%d).\n", - bdevname(bdev, name), ret); - } - spin_lock(&inode->i_lock); - } - spin_unlock(&inode->i_lock); -} - -/* Kill _all_ buffers and pagecache , dirty or not.. */ -static void kill_bdev(struct block_device *bdev) -{ - struct address_space *mapping = bdev->bd_inode->i_mapping; - - if (mapping_empty(mapping)) - return; - - invalidate_bh_lrus(); - truncate_inode_pages(mapping, 0); -} - -/* Invalidate clean unused buffers and pagecache. */ -void invalidate_bdev(struct block_device *bdev) -{ - struct address_space *mapping = bdev->bd_inode->i_mapping; - - if (mapping->nrpages) { - invalidate_bh_lrus(); - lru_add_drain_all(); /* make sure all lru add caches are flushed */ - invalidate_mapping_pages(mapping, 0, -1); - } - /* 99% of the time, we don't need to flush the cleancache on the bdev. - * But, for the strange corners, lets be cautious - */ - cleancache_invalidate_inode(mapping); -} -EXPORT_SYMBOL(invalidate_bdev); - -/* - * Drop all buffers & page cache for given bdev range. This function bails - * with error if bdev has other exclusive owner (such as filesystem). - */ -int truncate_bdev_range(struct block_device *bdev, fmode_t mode, - loff_t lstart, loff_t lend) -{ - /* - * If we don't hold exclusive handle for the device, upgrade to it - * while we discard the buffer cache to avoid discarding buffers - * under live filesystem. - */ - if (!(mode & FMODE_EXCL)) { - int err = bd_prepare_to_claim(bdev, truncate_bdev_range); - if (err) - goto invalidate; - } - - truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend); - if (!(mode & FMODE_EXCL)) - bd_abort_claiming(bdev, truncate_bdev_range); - return 0; - -invalidate: - /* - * Someone else has handle exclusively open. Try invalidating instead. - * The 'end' argument is inclusive so the rounding is safe. - */ - return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping, - lstart >> PAGE_SHIFT, - lend >> PAGE_SHIFT); -} - -static void set_init_blocksize(struct block_device *bdev) -{ - unsigned int bsize = bdev_logical_block_size(bdev); - loff_t size = i_size_read(bdev->bd_inode); - - while (bsize < PAGE_SIZE) { - if (size & bsize) - break; - bsize <<= 1; - } - bdev->bd_inode->i_blkbits = blksize_bits(bsize); -} - -int set_blocksize(struct block_device *bdev, int size) -{ - /* Size must be a power of two, and between 512 and PAGE_SIZE */ - if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) - return -EINVAL; - - /* Size cannot be smaller than the size supported by the device */ - if (size < bdev_logical_block_size(bdev)) - return -EINVAL; - - /* Don't change the size if it is same as current */ - if (bdev->bd_inode->i_blkbits != blksize_bits(size)) { - sync_blockdev(bdev); - bdev->bd_inode->i_blkbits = blksize_bits(size); - kill_bdev(bdev); - } - return 0; -} - -EXPORT_SYMBOL(set_blocksize); - -int sb_set_blocksize(struct super_block *sb, int size) -{ - if (set_blocksize(sb->s_bdev, size)) - return 0; - /* If we get here, we know size is power of two - * and it's value is between 512 and PAGE_SIZE */ - sb->s_blocksize = size; - sb->s_blocksize_bits = blksize_bits(size); - return sb->s_blocksize; -} - -EXPORT_SYMBOL(sb_set_blocksize); - -int sb_min_blocksize(struct super_block *sb, int size) -{ - int minsize = bdev_logical_block_size(sb->s_bdev); - if (size < minsize) - size = minsize; - return sb_set_blocksize(sb, size); -} - -EXPORT_SYMBOL(sb_min_blocksize); - -int __sync_blockdev(struct block_device *bdev, int wait) -{ - if (!bdev) - return 0; - if (!wait) - return filemap_flush(bdev->bd_inode->i_mapping); - return filemap_write_and_wait(bdev->bd_inode->i_mapping); -} - -/* - * Write out and wait upon all the dirty data associated with a block - * device via its mapping. Does not take the superblock lock. - */ -int sync_blockdev(struct block_device *bdev) -{ - return __sync_blockdev(bdev, 1); -} -EXPORT_SYMBOL(sync_blockdev); - -/* - * Write out and wait upon all dirty data associated with this - * device. Filesystem data as well as the underlying block - * device. Takes the superblock lock. - */ -int fsync_bdev(struct block_device *bdev) -{ - struct super_block *sb = get_super(bdev); - if (sb) { - int res = sync_filesystem(sb); - drop_super(sb); - return res; - } - return sync_blockdev(bdev); -} -EXPORT_SYMBOL(fsync_bdev); - -/** - * freeze_bdev -- lock a filesystem and force it into a consistent state - * @bdev: blockdevice to lock - * - * If a superblock is found on this device, we take the s_umount semaphore - * on it to make sure nobody unmounts until the snapshot creation is done. - * The reference counter (bd_fsfreeze_count) guarantees that only the last - * unfreeze process can unfreeze the frozen filesystem actually when multiple - * freeze requests arrive simultaneously. It counts up in freeze_bdev() and - * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze - * actually. - */ -int freeze_bdev(struct block_device *bdev) -{ - struct super_block *sb; - int error = 0; - - mutex_lock(&bdev->bd_fsfreeze_mutex); - if (++bdev->bd_fsfreeze_count > 1) - goto done; - - sb = get_active_super(bdev); - if (!sb) - goto sync; - if (sb->s_op->freeze_super) - error = sb->s_op->freeze_super(sb); - else - error = freeze_super(sb); - deactivate_super(sb); - - if (error) { - bdev->bd_fsfreeze_count--; - goto done; - } - bdev->bd_fsfreeze_sb = sb; - -sync: - sync_blockdev(bdev); -done: - mutex_unlock(&bdev->bd_fsfreeze_mutex); - return error; -} -EXPORT_SYMBOL(freeze_bdev); - -/** - * thaw_bdev -- unlock filesystem - * @bdev: blockdevice to unlock - * - * Unlocks the filesystem and marks it writeable again after freeze_bdev(). - */ -int thaw_bdev(struct block_device *bdev) -{ - struct super_block *sb; - int error = -EINVAL; - - mutex_lock(&bdev->bd_fsfreeze_mutex); - if (!bdev->bd_fsfreeze_count) - goto out; - - error = 0; - if (--bdev->bd_fsfreeze_count > 0) - goto out; - - sb = bdev->bd_fsfreeze_sb; - if (!sb) - goto out; - - if (sb->s_op->thaw_super) - error = sb->s_op->thaw_super(sb); - else - error = thaw_super(sb); - if (error) - bdev->bd_fsfreeze_count++; - else - bdev->bd_fsfreeze_sb = NULL; -out: - mutex_unlock(&bdev->bd_fsfreeze_mutex); - return error; -} -EXPORT_SYMBOL(thaw_bdev); - -/** - * bdev_read_page() - Start reading a page from a block device - * @bdev: The device to read the page from - * @sector: The offset on the device to read the page to (need not be aligned) - * @page: The page to read - * - * On entry, the page should be locked. It will be unlocked when the page - * has been read. If the block driver implements rw_page synchronously, - * that will be true on exit from this function, but it need not be. - * - * Errors returned by this function are usually "soft", eg out of memory, or - * queue full; callers should try a different route to read this page rather - * than propagate an error back up the stack. - * - * Return: negative errno if an error occurs, 0 if submission was successful. - */ -int bdev_read_page(struct block_device *bdev, sector_t sector, - struct page *page) -{ - const struct block_device_operations *ops = bdev->bd_disk->fops; - int result = -EOPNOTSUPP; - - if (!ops->rw_page || bdev_get_integrity(bdev)) - return result; - - result = blk_queue_enter(bdev->bd_disk->queue, 0); - if (result) - return result; - result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, - REQ_OP_READ); - blk_queue_exit(bdev->bd_disk->queue); - return result; -} - -/** - * bdev_write_page() - Start writing a page to a block device - * @bdev: The device to write the page to - * @sector: The offset on the device to write the page to (need not be aligned) - * @page: The page to write - * @wbc: The writeback_control for the write - * - * On entry, the page should be locked and not currently under writeback. - * On exit, if the write started successfully, the page will be unlocked and - * under writeback. If the write failed already (eg the driver failed to - * queue the page to the device), the page will still be locked. If the - * caller is a ->writepage implementation, it will need to unlock the page. - * - * Errors returned by this function are usually "soft", eg out of memory, or - * queue full; callers should try a different route to write this page rather - * than propagate an error back up the stack. - * - * Return: negative errno if an error occurs, 0 if submission was successful. - */ -int bdev_write_page(struct block_device *bdev, sector_t sector, - struct page *page, struct writeback_control *wbc) -{ - int result; - const struct block_device_operations *ops = bdev->bd_disk->fops; - - if (!ops->rw_page || bdev_get_integrity(bdev)) - return -EOPNOTSUPP; - result = blk_queue_enter(bdev->bd_disk->queue, 0); - if (result) - return result; - - set_page_writeback(page); - result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, - REQ_OP_WRITE); - if (result) { - end_page_writeback(page); - } else { - clean_page_buffers(page); - unlock_page(page); - } - blk_queue_exit(bdev->bd_disk->queue); - return result; -} - -/* - * pseudo-fs - */ - -static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); -static struct kmem_cache * bdev_cachep __read_mostly; - -static struct inode *bdev_alloc_inode(struct super_block *sb) -{ - struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL); - - if (!ei) - return NULL; - memset(&ei->bdev, 0, sizeof(ei->bdev)); - return &ei->vfs_inode; -} - -static void bdev_free_inode(struct inode *inode) -{ - struct block_device *bdev = I_BDEV(inode); - - free_percpu(bdev->bd_stats); - kfree(bdev->bd_meta_info); - - if (!bdev_is_partition(bdev)) { - if (bdev->bd_disk && bdev->bd_disk->bdi) - bdi_put(bdev->bd_disk->bdi); - kfree(bdev->bd_disk); - } - - if (MAJOR(bdev->bd_dev) == BLOCK_EXT_MAJOR) - blk_free_ext_minor(MINOR(bdev->bd_dev)); - - kmem_cache_free(bdev_cachep, BDEV_I(inode)); -} - -static void init_once(void *data) -{ - struct bdev_inode *ei = data; - - inode_init_once(&ei->vfs_inode); -} - -static void bdev_evict_inode(struct inode *inode) -{ - truncate_inode_pages_final(&inode->i_data); - invalidate_inode_buffers(inode); /* is it needed here? */ - clear_inode(inode); -} - -static const struct super_operations bdev_sops = { - .statfs = simple_statfs, - .alloc_inode = bdev_alloc_inode, - .free_inode = bdev_free_inode, - .drop_inode = generic_delete_inode, - .evict_inode = bdev_evict_inode, -}; - -static int bd_init_fs_context(struct fs_context *fc) -{ - struct pseudo_fs_context *ctx = init_pseudo(fc, BDEVFS_MAGIC); - if (!ctx) - return -ENOMEM; - fc->s_iflags |= SB_I_CGROUPWB; - ctx->ops = &bdev_sops; - return 0; -} - -static struct file_system_type bd_type = { - .name = "bdev", - .init_fs_context = bd_init_fs_context, - .kill_sb = kill_anon_super, -}; - -struct super_block *blockdev_superblock __read_mostly; -EXPORT_SYMBOL_GPL(blockdev_superblock); - -void __init bdev_cache_init(void) -{ - int err; - static struct vfsmount *bd_mnt; - - bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), - 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| - SLAB_MEM_SPREAD|SLAB_ACCOUNT|SLAB_PANIC), - init_once); - err = register_filesystem(&bd_type); - if (err) - panic("Cannot register bdev pseudo-fs"); - bd_mnt = kern_mount(&bd_type); - if (IS_ERR(bd_mnt)) - panic("Cannot create bdev pseudo-fs"); - blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ -} - -struct block_device *bdev_alloc(struct gendisk *disk, u8 partno) -{ - struct block_device *bdev; - struct inode *inode; - - inode = new_inode(blockdev_superblock); - if (!inode) - return NULL; - inode->i_mode = S_IFBLK; - inode->i_rdev = 0; - inode->i_data.a_ops = &def_blk_aops; - mapping_set_gfp_mask(&inode->i_data, GFP_USER); - - bdev = I_BDEV(inode); - mutex_init(&bdev->bd_fsfreeze_mutex); - spin_lock_init(&bdev->bd_size_lock); - bdev->bd_disk = disk; - bdev->bd_partno = partno; - bdev->bd_inode = inode; - bdev->bd_stats = alloc_percpu(struct disk_stats); - if (!bdev->bd_stats) { - iput(inode); - return NULL; - } - return bdev; -} - -void bdev_add(struct block_device *bdev, dev_t dev) -{ - bdev->bd_dev = dev; - bdev->bd_inode->i_rdev = dev; - bdev->bd_inode->i_ino = dev; - insert_inode_hash(bdev->bd_inode); -} - -long nr_blockdev_pages(void) -{ - struct inode *inode; - long ret = 0; - - spin_lock(&blockdev_superblock->s_inode_list_lock); - list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) - ret += inode->i_mapping->nrpages; - spin_unlock(&blockdev_superblock->s_inode_list_lock); - - return ret; -} - -/** - * bd_may_claim - test whether a block device can be claimed - * @bdev: block device of interest - * @whole: whole block device containing @bdev, may equal @bdev - * @holder: holder trying to claim @bdev - * - * Test whether @bdev can be claimed by @holder. - * - * CONTEXT: - * spin_lock(&bdev_lock). - * - * RETURNS: - * %true if @bdev can be claimed, %false otherwise. - */ -static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, - void *holder) -{ - if (bdev->bd_holder == holder) - return true; /* already a holder */ - else if (bdev->bd_holder != NULL) - return false; /* held by someone else */ - else if (whole == bdev) - return true; /* is a whole device which isn't held */ - - 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 */ - else - return true; /* is a partition of an un-held device */ -} - -/** - * bd_prepare_to_claim - claim a block device - * @bdev: block device of interest - * @holder: holder trying to claim @bdev - * - * Claim @bdev. This function fails if @bdev is already claimed by another - * holder and waits if another claiming is in progress. return, the caller - * has ownership of bd_claiming and bd_holder[s]. - * - * RETURNS: - * 0 if @bdev can be claimed, -EBUSY otherwise. - */ -int bd_prepare_to_claim(struct block_device *bdev, void *holder) -{ - struct block_device *whole = bdev_whole(bdev); - - if (WARN_ON_ONCE(!holder)) - return -EINVAL; -retry: - spin_lock(&bdev_lock); - /* if someone else claimed, fail */ - if (!bd_may_claim(bdev, whole, holder)) { - spin_unlock(&bdev_lock); - return -EBUSY; - } - - /* if claiming is already in progress, wait for it to finish */ - if (whole->bd_claiming) { - wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0); - DEFINE_WAIT(wait); - - prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); - spin_unlock(&bdev_lock); - schedule(); - finish_wait(wq, &wait); - goto retry; - } - - /* yay, all mine */ - whole->bd_claiming = holder; - spin_unlock(&bdev_lock); - return 0; -} -EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */ - -static void bd_clear_claiming(struct block_device *whole, void *holder) -{ - lockdep_assert_held(&bdev_lock); - /* tell others that we're done */ - BUG_ON(whole->bd_claiming != holder); - whole->bd_claiming = NULL; - wake_up_bit(&whole->bd_claiming, 0); -} - -/** - * bd_finish_claiming - finish claiming of a block device - * @bdev: block device of interest - * @holder: holder that has claimed @bdev - * - * Finish exclusive open of a block device. Mark the device as exlusively - * open by the holder and wake up all waiters for exclusive open to finish. - */ -static void bd_finish_claiming(struct block_device *bdev, void *holder) -{ - struct block_device *whole = bdev_whole(bdev); - - spin_lock(&bdev_lock); - 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; - bd_clear_claiming(whole, holder); - spin_unlock(&bdev_lock); -} - -/** - * bd_abort_claiming - abort claiming of a block device - * @bdev: block device of interest - * @holder: holder that has claimed @bdev - * - * Abort claiming of a block device when the exclusive open failed. This can be - * also used when exclusive open is not actually desired and we just needed - * to block other exclusive openers for a while. - */ -void bd_abort_claiming(struct block_device *bdev, void *holder) -{ - spin_lock(&bdev_lock); - bd_clear_claiming(bdev_whole(bdev), holder); - spin_unlock(&bdev_lock); -} -EXPORT_SYMBOL(bd_abort_claiming); - -static void blkdev_flush_mapping(struct block_device *bdev) -{ - WARN_ON_ONCE(bdev->bd_holders); - sync_blockdev(bdev); - kill_bdev(bdev); - bdev_write_inode(bdev); -} - -static int blkdev_get_whole(struct block_device *bdev, fmode_t mode) -{ - struct gendisk *disk = bdev->bd_disk; - int ret = 0; - - if (disk->fops->open) { - ret = disk->fops->open(bdev, mode); - if (ret) { - /* avoid ghost partitions on a removed medium */ - if (ret == -ENOMEDIUM && - test_bit(GD_NEED_PART_SCAN, &disk->state)) - bdev_disk_changed(disk, true); - return ret; - } - } - - if (!bdev->bd_openers) - set_init_blocksize(bdev); - if (test_bit(GD_NEED_PART_SCAN, &disk->state)) - bdev_disk_changed(disk, false); - bdev->bd_openers++; - return 0;; -} - -static void blkdev_put_whole(struct block_device *bdev, fmode_t mode) -{ - if (!--bdev->bd_openers) - blkdev_flush_mapping(bdev); - if (bdev->bd_disk->fops->release) - bdev->bd_disk->fops->release(bdev->bd_disk, mode); -} - -static int blkdev_get_part(struct block_device *part, fmode_t mode) -{ - struct gendisk *disk = part->bd_disk; - int ret; - - if (part->bd_openers) - goto done; - - ret = blkdev_get_whole(bdev_whole(part), mode); - if (ret) - return ret; - - ret = -ENXIO; - if (!bdev_nr_sectors(part)) - goto out_blkdev_put; - - disk->open_partitions++; - set_init_blocksize(part); -done: - part->bd_openers++; - return 0; - -out_blkdev_put: - blkdev_put_whole(bdev_whole(part), mode); - return ret; -} - -static void blkdev_put_part(struct block_device *part, fmode_t mode) -{ - struct block_device *whole = bdev_whole(part); - - if (--part->bd_openers) - return; - blkdev_flush_mapping(part); - whole->bd_disk->open_partitions--; - blkdev_put_whole(whole, mode); -} - -struct block_device *blkdev_get_no_open(dev_t dev) -{ - struct block_device *bdev; - struct inode *inode; - - inode = ilookup(blockdev_superblock, dev); - if (!inode) { - blk_request_module(dev); - inode = ilookup(blockdev_superblock, dev); - if (!inode) - return NULL; - } - - /* switch from the inode reference to a device mode one: */ - bdev = &BDEV_I(inode)->bdev; - if (!kobject_get_unless_zero(&bdev->bd_device.kobj)) - bdev = NULL; - iput(inode); - - if (!bdev) - return NULL; - if ((bdev->bd_disk->flags & GENHD_FL_HIDDEN) || - !try_module_get(bdev->bd_disk->fops->owner)) { - put_device(&bdev->bd_device); - return NULL; - } - - return bdev; -} - -void blkdev_put_no_open(struct block_device *bdev) -{ - module_put(bdev->bd_disk->fops->owner); - put_device(&bdev->bd_device); -} - -/** - * 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 block device described by device number @dev. If @mode includes - * %FMODE_EXCL, the block device is opened with exclusive access. Specifying - * %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may nest for - * the same @holder. - * - * Use this interface ONLY if you really do not have anything better - i.e. when - * you are behind a truly sucky interface and all you are given is a device - * number. Everything else should use blkdev_get_by_path(). - * - * CONTEXT: - * Might sleep. - * - * RETURNS: - * Reference to the block_device on success, ERR_PTR(-errno) on failure. - */ -struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) -{ - bool unblock_events = true; - struct block_device *bdev; - struct gendisk *disk; - int ret; - - ret = devcgroup_check_permission(DEVCG_DEV_BLOCK, - MAJOR(dev), MINOR(dev), - ((mode & FMODE_READ) ? DEVCG_ACC_READ : 0) | - ((mode & FMODE_WRITE) ? DEVCG_ACC_WRITE : 0)); - if (ret) - return ERR_PTR(ret); - - bdev = blkdev_get_no_open(dev); - if (!bdev) - return ERR_PTR(-ENXIO); - disk = bdev->bd_disk; - - if (mode & FMODE_EXCL) { - ret = bd_prepare_to_claim(bdev, holder); - if (ret) - goto put_blkdev; - } - - disk_block_events(disk); - - mutex_lock(&disk->open_mutex); - ret = -ENXIO; - if (!disk_live(disk)) - goto abort_claiming; - if (bdev_is_partition(bdev)) - ret = blkdev_get_part(bdev, mode); - else - ret = blkdev_get_whole(bdev, mode); - if (ret) - goto abort_claiming; - if (mode & FMODE_EXCL) { - bd_finish_claiming(bdev, holder); - - /* - * Block event polling for write claims if requested. 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 ((mode & FMODE_WRITE) && !bdev->bd_write_holder && - (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) { - bdev->bd_write_holder = true; - unblock_events = false; - } - } - mutex_unlock(&disk->open_mutex); - - if (unblock_events) - disk_unblock_events(disk); - return bdev; - -abort_claiming: - if (mode & FMODE_EXCL) - bd_abort_claiming(bdev, holder); - mutex_unlock(&disk->open_mutex); - disk_unblock_events(disk); -put_blkdev: - blkdev_put_no_open(bdev); - return ERR_PTR(ret); -} -EXPORT_SYMBOL(blkdev_get_by_dev); - -/** - * 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 block device described by the device file at @path. If @mode - * includes %FMODE_EXCL, the block device is opened with exclusive access. - * Specifying %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may - * nest for the same @holder. - * - * CONTEXT: - * Might sleep. - * - * RETURNS: - * Reference to the block_device on success, ERR_PTR(-errno) on failure. - */ -struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, - void *holder) -{ - struct block_device *bdev; - dev_t dev; - int error; - - error = lookup_bdev(path, &dev); - if (error) - return ERR_PTR(error); - - bdev = blkdev_get_by_dev(dev, mode, holder); - if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) { - blkdev_put(bdev, mode); - return ERR_PTR(-EACCES); - } - - return bdev; -} -EXPORT_SYMBOL(blkdev_get_by_path); - -void blkdev_put(struct block_device *bdev, fmode_t mode) -{ - struct gendisk *disk = bdev->bd_disk; - - /* - * Sync early if it looks like we're the last one. If someone else - * opens the block device between now and the decrement of bd_openers - * then we did a sync that we didn't need to, but that's not the end - * of the world and we want to avoid long (could be several minute) - * syncs while holding the mutex. - */ - if (bdev->bd_openers == 1) - sync_blockdev(bdev); - - mutex_lock(&disk->open_mutex); - if (mode & FMODE_EXCL) { - struct block_device *whole = bdev_whole(bdev); - bool bdev_free; - - /* - * Release a claim on the device. The holder fields - * are protected with bdev_lock. open_mutex is to - * synchronize disk_holder unlinking. - */ - spin_lock(&bdev_lock); - - WARN_ON_ONCE(--bdev->bd_holders < 0); - WARN_ON_ONCE(--whole->bd_holders < 0); - - if ((bdev_free = !bdev->bd_holders)) - bdev->bd_holder = NULL; - if (!whole->bd_holders) - whole->bd_holder = NULL; - - spin_unlock(&bdev_lock); - - /* - * If this was the last claim, remove holder link and - * unblock evpoll if it was a write holder. - */ - if (bdev_free && bdev->bd_write_holder) { - disk_unblock_events(disk); - bdev->bd_write_holder = false; - } - } - - /* - * Trigger event checking and tell drivers to flush MEDIA_CHANGE - * event. This is to ensure detection of media removal commanded - * from userland - e.g. eject(1). - */ - disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE); - - if (bdev_is_partition(bdev)) - blkdev_put_part(bdev, mode); - else - blkdev_put_whole(bdev, mode); - mutex_unlock(&disk->open_mutex); - - blkdev_put_no_open(bdev); -} -EXPORT_SYMBOL(blkdev_put); - -/** - * lookup_bdev - lookup a struct block_device by name - * @pathname: special file representing the block device - * @dev: return value of the block device's dev_t - * - * Get a reference to the blockdevice at @pathname in the current - * namespace if possible and return it. Return ERR_PTR(error) - * otherwise. - */ -int lookup_bdev(const char *pathname, dev_t *dev) -{ - struct inode *inode; - struct path path; - int error; - - if (!pathname || !*pathname) - return -EINVAL; - - error = kern_path(pathname, LOOKUP_FOLLOW, &path); - if (error) - return error; - - inode = d_backing_inode(path.dentry); - error = -ENOTBLK; - if (!S_ISBLK(inode->i_mode)) - goto out_path_put; - error = -EACCES; - if (!may_open_dev(&path)) - goto out_path_put; - - *dev = inode->i_rdev; - error = 0; -out_path_put: - path_put(&path); - return error; -} -EXPORT_SYMBOL(lookup_bdev); - -int __invalidate_device(struct block_device *bdev, bool kill_dirty) -{ - struct super_block *sb = get_super(bdev); - int res = 0; - - if (sb) { - /* - * no need to lock the super, get_super holds the - * read mutex so the filesystem cannot go away - * under us (->put_super runs with the write lock - * hold). - */ - shrink_dcache_sb(sb); - res = invalidate_inodes(sb, kill_dirty); - drop_super(sb); - } - invalidate_bdev(bdev); - return res; -} -EXPORT_SYMBOL(__invalidate_device); - -void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg) -{ - struct inode *inode, *old_inode = NULL; - - spin_lock(&blockdev_superblock->s_inode_list_lock); - list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) { - struct address_space *mapping = inode->i_mapping; - struct block_device *bdev; - - spin_lock(&inode->i_lock); - if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) || - mapping->nrpages == 0) { - spin_unlock(&inode->i_lock); - continue; - } - __iget(inode); - spin_unlock(&inode->i_lock); - spin_unlock(&blockdev_superblock->s_inode_list_lock); - /* - * We hold a reference to 'inode' so it couldn't have been - * removed from s_inodes list while we dropped the - * s_inode_list_lock We cannot iput the inode now as we can - * be holding the last reference and we cannot iput it under - * s_inode_list_lock. So we keep the reference and iput it - * later. - */ - iput(old_inode); - old_inode = inode; - bdev = I_BDEV(inode); - - mutex_lock(&bdev->bd_disk->open_mutex); - if (bdev->bd_openers) - func(bdev, arg); - mutex_unlock(&bdev->bd_disk->open_mutex); - - spin_lock(&blockdev_superblock->s_inode_list_lock); - } - spin_unlock(&blockdev_superblock->s_inode_list_lock); - iput(old_inode); -} diff --git a/fs/internal.h b/fs/internal.h index 68a2ae029a27..3cd065c8a66b 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -18,7 +18,7 @@ struct user_namespace; struct pipe_inode_info; /* - * block_dev.c + * block/bdev.c */ #ifdef CONFIG_BLOCK extern void __init bdev_cache_init(void); -- cgit v1.2.3-59-g8ed1b