.. kernel-doc:: block/genhd.c
:export:
+.. kernel-doc:: block/bdev.c
+ :export:
+
Char devices
============
.. kernel-doc:: fs/fs-writeback.c
:export:
-.. kernel-doc:: fs/block_dev.c
- :export:
-
.. kernel-doc:: fs/anon_inodes.c
:export:
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
# 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 \
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
+ * Copyright (C) 2016 - 2020 Christoph Hellwig
+ */
+
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/kmod.h>
+#include <linux/major.h>
+#include <linux/device_cgroup.h>
+#include <linux/blkdev.h>
+#include <linux/backing-dev.h>
+#include <linux/module.h>
+#include <linux/blkpg.h>
+#include <linux/magic.h>
+#include <linux/buffer_head.h>
+#include <linux/swap.h>
+#include <linux/writeback.h>
+#include <linux/mount.h>
+#include <linux/pseudo_fs.h>
+#include <linux/uio.h>
+#include <linux/namei.h>
+#include <linux/cleancache.h>
+#include <linux/part_stat.h>
+#include <linux/uaccess.h>
+#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);
+}
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
+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Copyright (C) 1991, 1992 Linus Torvalds
- * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
- * Copyright (C) 2016 - 2020 Christoph Hellwig
- */
-
-#include <linux/init.h>
-#include <linux/mm.h>
-#include <linux/slab.h>
-#include <linux/kmod.h>
-#include <linux/major.h>
-#include <linux/device_cgroup.h>
-#include <linux/blkdev.h>
-#include <linux/backing-dev.h>
-#include <linux/module.h>
-#include <linux/blkpg.h>
-#include <linux/magic.h>
-#include <linux/buffer_head.h>
-#include <linux/swap.h>
-#include <linux/writeback.h>
-#include <linux/mount.h>
-#include <linux/pseudo_fs.h>
-#include <linux/uio.h>
-#include <linux/namei.h>
-#include <linux/cleancache.h>
-#include <linux/part_stat.h>
-#include <linux/uaccess.h>
-#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);
-}
struct pipe_inode_info;
/*
- * block_dev.c
+ * block/bdev.c
*/
#ifdef CONFIG_BLOCK
extern void __init bdev_cache_init(void);
projects / linux-2.6-microblaze.git / commitdiff