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libnvdimm for v5.15

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- Fix a race condition in the teardown path of raw mode pmem namespaces.
 
 - Cleanup the code that filesystems use to detect filesystem-dax
   capabilities of their underlying block device.
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Merge tag 'libnvdimm-for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm updates from Dan Williams:

 - Fix a race condition in the teardown path of raw mode pmem
   namespaces.

 - Cleanup the code that filesystems use to detect filesystem-dax
   capabilities of their underlying block device.

* tag 'libnvdimm-for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  dax: remove bdev_dax_supported
  xfs: factor out a xfs_buftarg_is_dax helper
  dax: stub out dax_supported for !CONFIG_FS_DAX
  dax: remove __generic_fsdax_supported
  dax: move the dax_read_lock() locking into dax_supported
  dax: mark dax_get_by_host static
  dm: use fs_dax_get_by_bdev instead of dax_get_by_host
  dax: stop using bdevname
  fsdax: improve the FS_DAX Kconfig description and help text
  libnvdimm/pmem: Fix crash triggered when I/O in-flight during unbind
This commit is contained in:
Linus Torvalds 2021-09-09 11:39:57 -07:00
commit 2e5fd489a4
10 changed files with 120 additions and 172 deletions
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191
drivers/dax/super.c
View File

@ -17,6 +17,24 @@
#include <linux/fs.h>
#include "dax-private.h"
/**
* struct dax_device - anchor object for dax services
* @inode: core vfs
* @cdev: optional character interface for "device dax"
* @host: optional name for lookups where the device path is not available
* @private: dax driver private data
* @flags: state and boolean properties
*/
struct dax_device {
struct hlist_node list;
struct inode inode;
struct cdev cdev;
const char *host;
void *private;
unsigned long flags;
const struct dax_operations *ops;
};
static dev_t dax_devt;
DEFINE_STATIC_SRCU(dax_srcu);
static struct vfsmount *dax_mnt;
@ -40,6 +58,42 @@ void dax_read_unlock(int id)
}
EXPORT_SYMBOL_GPL(dax_read_unlock);
static int dax_host_hash(const char *host)
{
return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE;
}
/**
* dax_get_by_host() - temporary lookup mechanism for filesystem-dax
* @host: alternate name for the device registered by a dax driver
*/
static struct dax_device *dax_get_by_host(const char *host)
{
struct dax_device *dax_dev, *found = NULL;
int hash, id;
if (!host)
return NULL;
hash = dax_host_hash(host);
id = dax_read_lock();
spin_lock(&dax_host_lock);
hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) {
if (!dax_alive(dax_dev)
|| strcmp(host, dax_dev->host) != 0)
continue;
if (igrab(&dax_dev->inode))
found = dax_dev;
break;
}
spin_unlock(&dax_host_lock);
dax_read_unlock(id);
return found;
}
#ifdef CONFIG_BLOCK
#include <linux/blkdev.h>
@ -65,15 +119,13 @@ struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
return dax_get_by_host(bdev->bd_disk->disk_name);
}
EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev);
#endif
bool __generic_fsdax_supported(struct dax_device *dax_dev,
bool generic_fsdax_supported(struct dax_device *dax_dev,
struct block_device *bdev, int blocksize, sector_t start,
sector_t sectors)
{
bool dax_enabled = false;
pgoff_t pgoff, pgoff_end;
char buf[BDEVNAME_SIZE];
void *kaddr, *end_kaddr;
pfn_t pfn, end_pfn;
sector_t last_page;
@ -81,29 +133,25 @@ bool __generic_fsdax_supported(struct dax_device *dax_dev,
int err, id;
if (blocksize != PAGE_SIZE) {
pr_info("%s: error: unsupported blocksize for dax\n",
bdevname(bdev, buf));
pr_info("%pg: error: unsupported blocksize for dax\n", bdev);
return false;
}
if (!dax_dev) {
pr_debug("%s: error: dax unsupported by block device\n",
bdevname(bdev, buf));
pr_debug("%pg: error: dax unsupported by block device\n", bdev);
return false;
}
err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff);
if (err) {
pr_info("%s: error: unaligned partition for dax\n",
bdevname(bdev, buf));
pr_info("%pg: error: unaligned partition for dax\n", bdev);
return false;
}
last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512;
err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end);
if (err) {
pr_info("%s: error: unaligned partition for dax\n",
bdevname(bdev, buf));
pr_info("%pg: error: unaligned partition for dax\n", bdev);
return false;
}
@ -112,8 +160,8 @@ bool __generic_fsdax_supported(struct dax_device *dax_dev,
len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn);
if (len < 1 || len2 < 1) {
pr_info("%s: error: dax access failed (%ld)\n",
bdevname(bdev, buf), len < 1 ? len : len2);
pr_info("%pg: error: dax access failed (%ld)\n",
bdev, len < 1 ? len : len2);
dax_read_unlock(id);
return false;
}
@ -147,57 +195,32 @@ bool __generic_fsdax_supported(struct dax_device *dax_dev,
dax_read_unlock(id);
if (!dax_enabled) {
pr_info("%s: error: dax support not enabled\n",
bdevname(bdev, buf));
pr_info("%pg: error: dax support not enabled\n", bdev);
return false;
}
return true;
}
EXPORT_SYMBOL_GPL(__generic_fsdax_supported);
EXPORT_SYMBOL_GPL(generic_fsdax_supported);
/**
* __bdev_dax_supported() - Check if the device supports dax for filesystem
* @bdev: block device to check
* @blocksize: The block size of the device
*
* This is a library function for filesystems to check if the block device
* can be mounted with dax option.
*
* Return: true if supported, false if unsupported
*/
bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
int blocksize, sector_t start, sector_t len)
{
struct dax_device *dax_dev;
struct request_queue *q;
char buf[BDEVNAME_SIZE];
bool ret;
bool ret = false;
int id;
q = bdev_get_queue(bdev);
if (!q || !blk_queue_dax(q)) {
pr_debug("%s: error: request queue doesn't support dax\n",
bdevname(bdev, buf));
if (!dax_dev)
return false;
}
dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
if (!dax_dev) {
pr_debug("%s: error: device does not support dax\n",
bdevname(bdev, buf));
return false;
}
id = dax_read_lock();
ret = dax_supported(dax_dev, bdev, blocksize, 0,
i_size_read(bdev->bd_inode) / 512);
if (dax_alive(dax_dev) && dax_dev->ops->dax_supported)
ret = dax_dev->ops->dax_supported(dax_dev, bdev, blocksize,
start, len);
dax_read_unlock(id);
put_dax(dax_dev);
return ret;
}
EXPORT_SYMBOL_GPL(__bdev_dax_supported);
#endif
EXPORT_SYMBOL_GPL(dax_supported);
#endif /* CONFIG_FS_DAX */
#endif /* CONFIG_BLOCK */
enum dax_device_flags {
/* !alive + rcu grace period == no new operations / mappings */
@ -208,24 +231,6 @@ enum dax_device_flags {
DAXDEV_SYNC,
};
/**
* struct dax_device - anchor object for dax services
* @inode: core vfs
* @cdev: optional character interface for "device dax"
* @host: optional name for lookups where the device path is not available
* @private: dax driver private data
* @flags: state and boolean properties
*/
struct dax_device {
struct hlist_node list;
struct inode inode;
struct cdev cdev;
const char *host;
void *private;
unsigned long flags;
const struct dax_operations *ops;
};
static ssize_t write_cache_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@ -323,19 +328,6 @@ long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
}
EXPORT_SYMBOL_GPL(dax_direct_access);
bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
int blocksize, sector_t start, sector_t len)
{
if (!dax_dev)
return false;
if (!dax_alive(dax_dev))
return false;
return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len);
}
EXPORT_SYMBOL_GPL(dax_supported);
size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
size_t bytes, struct iov_iter *i)
{
@ -423,11 +415,6 @@ bool dax_alive(struct dax_device *dax_dev)
}
EXPORT_SYMBOL_GPL(dax_alive);
static int dax_host_hash(const char *host)
{
return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE;
}
/*
* Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring
* that any fault handlers or operations that might have seen
@ -624,38 +611,6 @@ void put_dax(struct dax_device *dax_dev)
}
EXPORT_SYMBOL_GPL(put_dax);
/**
* dax_get_by_host() - temporary lookup mechanism for filesystem-dax
* @host: alternate name for the device registered by a dax driver
*/
struct dax_device *dax_get_by_host(const char *host)
{
struct dax_device *dax_dev, *found = NULL;
int hash, id;
if (!host)
return NULL;
hash = dax_host_hash(host);
id = dax_read_lock();
spin_lock(&dax_host_lock);
hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) {
if (!dax_alive(dax_dev)
|| strcmp(host, dax_dev->host) != 0)
continue;
if (igrab(&dax_dev->inode))
found = dax_dev;
break;
}
spin_unlock(&dax_host_lock);
dax_read_unlock(id);
return found;
}
EXPORT_SYMBOL_GPL(dax_get_by_host);
/**
* inode_dax: convert a public inode into its dax_dev
* @inode: An inode with i_cdev pointing to a dax_dev

9
drivers/md/dm-table.c
View File

@ -809,14 +809,9 @@ EXPORT_SYMBOL_GPL(dm_table_set_type);
int device_not_dax_capable(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
int blocksize = *(int *) data, id;
bool rc;
int blocksize = *(int *) data;
id = dax_read_lock();
rc = !dax_supported(dev->dax_dev, dev->bdev, blocksize, start, len);
dax_read_unlock(id);
return rc;
return !dax_supported(dev->dax_dev, dev->bdev, blocksize, start, len);
}
/* Check devices support synchronous DAX */

2
drivers/md/dm.c
View File

@ -654,7 +654,7 @@ static int open_table_device(struct table_device *td, dev_t dev,
}
td->dm_dev.bdev = bdev;
td->dm_dev.dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
td->dm_dev.dax_dev = fs_dax_get_by_bdev(bdev);
return 0;
}

4
drivers/nvdimm/pmem.c
View File

@ -450,11 +450,11 @@ static int pmem_attach_disk(struct device *dev,
pmem->pfn_flags |= PFN_MAP;
bb_range = pmem->pgmap.range;
} else {
addr = devm_memremap(dev, pmem->phys_addr,
pmem->size, ARCH_MEMREMAP_PMEM);
if (devm_add_action_or_reset(dev, pmem_release_queue,
&pmem->pgmap))
return -ENOMEM;
addr = devm_memremap(dev, pmem->phys_addr,
pmem->size, ARCH_MEMREMAP_PMEM);
bb_range.start = res->start;
bb_range.end = res->end;
}

21
fs/Kconfig
View File

@ -43,7 +43,7 @@ source "fs/f2fs/Kconfig"
source "fs/zonefs/Kconfig"
config FS_DAX
bool "Direct Access (DAX) support"
bool "File system based Direct Access (DAX) support"
depends on MMU
depends on !(ARM || MIPS || SPARC)
select DEV_PAGEMAP_OPS if (ZONE_DEVICE && !FS_DAX_LIMITED)
@ -53,8 +53,23 @@ config FS_DAX
Direct Access (DAX) can be used on memory-backed block devices.
If the block device supports DAX and the filesystem supports DAX,
then you can avoid using the pagecache to buffer I/Os. Turning
on this option will compile in support for DAX; you will need to
mount the filesystem using the -o dax option.
on this option will compile in support for DAX.
For a DAX device to support file system access it needs to have
struct pages. For the nfit based NVDIMMs this can be enabled
using the ndctl utility:
# ndctl create-namespace --force --reconfig=namespace0.0 \
--mode=fsdax --map=mem
See the 'create-namespace' man page for details on the overhead of
--map=mem:
https://docs.pmem.io/ndctl-user-guide/ndctl-man-pages/ndctl-create-namespace
For ndctl to work CONFIG_DEV_DAX needs to be enabled as well. For most
file systems DAX support needs to be manually enabled globally or
per-inode using a mount option as well. See the file documentation in
Documentation/filesystems/dax.rst for details.
If you do not have a block device that is capable of using this,
or if unsure, say N. Saying Y will increase the size of the kernel

2
fs/erofs/super.c
View File

@ -546,7 +546,7 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
return err;
if (test_opt(ctx, DAX_ALWAYS) &&
!bdev_dax_supported(sb->s_bdev, EROFS_BLKSIZ)) {
!dax_supported(sbi->dax_dev, sb->s_bdev, EROFS_BLKSIZ, 0, bdev_nr_sectors(sb->s_bdev))) {
errorfc(fc, "DAX unsupported by block device. Turning off DAX.");
clear_opt(ctx, DAX_ALWAYS);
}

3
fs/ext2/super.c
View File

@ -946,7 +946,8 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
if (test_opt(sb, DAX)) {
if (!bdev_dax_supported(sb->s_bdev, blocksize)) {
if (!dax_supported(dax_dev, sb->s_bdev, blocksize, 0,
bdev_nr_sectors(sb->s_bdev))) {
ext2_msg(sb, KERN_ERR,
"DAX unsupported by block device. Turning off DAX.");
clear_opt(sbi->s_mount_opt, DAX);

3
fs/ext4/super.c
View File

@ -4287,7 +4287,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
goto failed_mount;
}
if (bdev_dax_supported(sb->s_bdev, blocksize))
if (dax_supported(dax_dev, sb->s_bdev, blocksize, 0,
bdev_nr_sectors(sb->s_bdev)))
set_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags);
if (sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS) {

16
fs/xfs/xfs_super.c
View File

@ -330,6 +330,15 @@ xfs_set_inode_alloc(
return xfs_is_inode32(mp) ? maxagi : agcount;
}
static bool
xfs_buftarg_is_dax(
struct super_block *sb,
struct xfs_buftarg *bt)
{
return dax_supported(bt->bt_daxdev, bt->bt_bdev, sb->s_blocksize, 0,
bdev_nr_sectors(bt->bt_bdev));
}
STATIC int
xfs_blkdev_get(
xfs_mount_t *mp,
@ -1588,11 +1597,10 @@ xfs_fs_fill_super(
xfs_warn(mp,
"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
datadev_is_dax = bdev_dax_supported(mp->m_ddev_targp->bt_bdev,
sb->s_blocksize);
datadev_is_dax = xfs_buftarg_is_dax(sb, mp->m_ddev_targp);
if (mp->m_rtdev_targp)
rtdev_is_dax = bdev_dax_supported(
mp->m_rtdev_targp->bt_bdev, sb->s_blocksize);
rtdev_is_dax = xfs_buftarg_is_dax(sb,
mp->m_rtdev_targp);
if (!rtdev_is_dax && !datadev_is_dax) {
xfs_alert(mp,
"DAX unsupported by block device. Turning off DAX.");

41
include/linux/dax.h
View File

@ -41,7 +41,6 @@ struct dax_operations {
extern struct attribute_group dax_attribute_group;
#if IS_ENABLED(CONFIG_DAX)
struct dax_device *dax_get_by_host(const char *host);
struct dax_device *alloc_dax(void *private, const char *host,
const struct dax_operations *ops, unsigned long flags);
void put_dax(struct dax_device *dax_dev);
@ -58,8 +57,6 @@ static inline void set_dax_synchronous(struct dax_device *dax_dev)
{
__set_dax_synchronous(dax_dev);
}
bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
int blocksize, sector_t start, sector_t len);
/*
* Check if given mapping is supported by the file / underlying device.
*/
@ -73,10 +70,6 @@ static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
return dax_synchronous(dax_dev);
}
#else
static inline struct dax_device *dax_get_by_host(const char *host)
{
return NULL;
}
static inline struct dax_device *alloc_dax(void *private, const char *host,
const struct dax_operations *ops, unsigned long flags)
{
@ -106,12 +99,6 @@ static inline bool dax_synchronous(struct dax_device *dax_dev)
static inline void set_dax_synchronous(struct dax_device *dax_dev)
{
}
static inline bool dax_supported(struct dax_device *dax_dev,
struct block_device *bdev, int blocksize, sector_t start,
sector_t len)
{
return false;
}
static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
struct dax_device *dax_dev)
{
@ -122,22 +109,12 @@ static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
struct writeback_control;
int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
#if IS_ENABLED(CONFIG_FS_DAX)
bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
{
return __bdev_dax_supported(bdev, blocksize);
}
bool __generic_fsdax_supported(struct dax_device *dax_dev,
bool generic_fsdax_supported(struct dax_device *dax_dev,
struct block_device *bdev, int blocksize, sector_t start,
sector_t sectors);
static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
struct block_device *bdev, int blocksize, sector_t start,
sector_t sectors)
{
return __generic_fsdax_supported(dax_dev, bdev, blocksize, start,
sectors);
}
bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
int blocksize, sector_t start, sector_t len);
static inline void fs_put_dax(struct dax_device *dax_dev)
{
@ -153,15 +130,11 @@ struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t st
dax_entry_t dax_lock_page(struct page *page);
void dax_unlock_page(struct page *page, dax_entry_t cookie);
#else
static inline bool bdev_dax_supported(struct block_device *bdev,
int blocksize)
{
return false;
}
#define generic_fsdax_supported NULL
static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
static inline bool dax_supported(struct dax_device *dax_dev,
struct block_device *bdev, int blocksize, sector_t start,
sector_t sectors)
sector_t len)
{
return false;
}