Al pointed out that we can just toss out the old name on a device and add a
new one arbitrarily, so anybody who uses device->name in printk could
possibly use free'd memory. Instead of adding locking around all of this he
suggested doing it with RCU, so I've introduced a struct rcu_string that
does just that and have gone through and protected all accesses to
device->name that aren't under the uuid_mutex with rcu_read_lock(). This
protects us and I will use it for dealing with removing the device that we
used to mount the file system in a later patch. Thanks,
Signed-off-by: Josef Bacik <jo...@redhat.com>
---
fs/btrfs/check-integrity.c | 11 ++++-
fs/btrfs/disk-io.c | 14 +++++-
fs/btrfs/extent_io.c | 7 +++-
fs/btrfs/ioctl.c | 14 +++++-
fs/btrfs/scrub.c | 39 ++++++++++++++---
fs/btrfs/volumes.c | 102 ++++++++++++++++++++++++++++++++------------
fs/btrfs/volumes.h | 2 +-
7 files changed, 147 insertions(+), 42 deletions(-)
diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index 9cebb1f..9f69855 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -93,6 +93,7 @@
#include "print-tree.h"
#include "locking.h"
#include "check-integrity.h"
+#include "rcu-string.h"
#define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
#define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
@@ -842,14 +843,20 @@ static int btrfsic_process_superblock_dev_mirror(
superblock_tmp->is_iodone = 1;
superblock_tmp->never_written = 0;
superblock_tmp->mirror_num = 1 + superblock_mirror_num;
- if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
+ if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE) {
+ struct rcu_string *name;
+
+ rcu_read_lock();
+ name = rcu_dereference(device->name);
printk(KERN_INFO "New initial S-block (bdev %p, %s)"
" @%llu (%s/%llu/%d)\n",
- superblock_bdev, device->name,
+ superblock_bdev, name->str,
(unsigned long long)dev_bytenr,
dev_state->name,
(unsigned long long)dev_bytenr,
superblock_mirror_num);
+ rcu_read_unlock();
+ }
list_add(&superblock_tmp->all_blocks_node,
&state->all_blocks_list);
btrfsic_block_hashtable_add(superblock_tmp,
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e39a3b9..c3fa508 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -44,6 +44,7 @@
#include "free-space-cache.h"
#include "inode-map.h"
#include "check-integrity.h"
+#include "rcu-string.h"
static struct extent_io_ops btree_extent_io_ops;
static void end_workqueue_fn(struct btrfs_work *work);
@@ -2574,12 +2575,16 @@ static void btrfs_end_buffer_write_sync(struct
buffer_head *bh, int uptodate)
} else {
struct btrfs_device *device = (struct btrfs_device *)
bh->b_private;
+ struct rcu_string *name;
+ rcu_read_lock();
+ name = rcu_dereference(device->name);
printk_ratelimited(KERN_WARNING "lost page write due to "
- "I/O error on %s\n", device->name);
+ "I/O error on %s\n", name->str);
/* note, we dont' set_buffer_write_io_error because we have
* our own ways of dealing with the IO errors
*/
+ rcu_read_unlock();
clear_buffer_uptodate(bh);
btrfs_dev_stat_inc_and_print(device, BTRFS_DEV_STAT_WRITE_ERRS);
}
@@ -2749,8 +2754,13 @@ static int write_dev_flush(struct btrfs_device *device,
int wait)
wait_for_completion(&device->flush_wait);
if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
+ struct rcu_string *name;
+
+ rcu_read_lock();
+ name = rcu_dereference(device->name);
printk("btrfs: disabling barriers on dev %s\n",
- device->name);
+ name->str);
+ rcu_read_unlock();
device->nobarriers = 1;
}
if (!bio_flagged(bio, BIO_UPTODATE)) {
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 2c8f7b2..d79a815 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -20,6 +20,7 @@
#include "volumes.h"
#include "check-integrity.h"
#include "locking.h"
+#include "rcu-string.h"
static struct kmem_cache *extent_state_cache;
static struct kmem_cache *extent_buffer_cache;
@@ -1874,6 +1875,7 @@ int repair_io_failure(struct btrfs_mapping_tree
*map_tree, u64 start,
{
struct bio *bio;
struct btrfs_device *dev;
+ struct rcu_string *name;
DECLARE_COMPLETION_ONSTACK(compl);
u64 map_length = 0;
u64 sector;
@@ -1917,9 +1919,12 @@ int repair_io_failure(struct btrfs_mapping_tree
*map_tree, u64 start,
return -EIO;
}
+ rcu_read_lock();
+ name = rcu_dereference(dev->name);
printk(KERN_INFO "btrfs read error corrected: ino %lu off %llu (dev %s "
"sector %llu)\n", page->mapping->host->i_ino, start,
- dev->name, sector);
+ name->str, sector);
+ rcu_read_unlock();
bio_put(bio);
return 0;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 24b776c..f4d01d9 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -52,6 +52,7 @@
#include "locking.h"
#include "inode-map.h"
#include "backref.h"
+#include "rcu-string.h"
/* Mask out flags that are inappropriate for the given type of inode. */
static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
@@ -1260,6 +1261,7 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root
*root,
struct btrfs_ioctl_vol_args *vol_args;
struct btrfs_trans_handle *trans;
struct btrfs_device *device = NULL;
+ struct rcu_string *name;
char *sizestr;
char *devstr = NULL;
int ret = 0;
@@ -1345,8 +1347,11 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root
*root,
do_div(new_size, root->sectorsize);
new_size *= root->sectorsize;
+ rcu_read_lock();
+ name = rcu_dereference(device->name);
printk(KERN_INFO "btrfs: new size for %s is %llu\n",
- device->name, (unsigned long long)new_size);
+ name->str, (unsigned long long)new_size);
+ rcu_read_unlock();
if (new_size > old_size) {
trans = btrfs_start_transaction(root, 0);
@@ -2264,7 +2269,12 @@ static long btrfs_ioctl_dev_info(struct btrfs_root
*root, void __user *arg)
di_args->total_bytes = dev->total_bytes;
memcpy(di_args->uuid, dev->uuid, sizeof(di_args->uuid));
if (dev->name) {
- strncpy(di_args->path, dev->name, sizeof(di_args->path));
+ struct rcu_string *name;
+
+ rcu_read_lock();
+ name = rcu_dereference(dev->name);
+ strncpy(di_args->path, name->str, sizeof(di_args->path));
+ rcu_read_unlock();
di_args->path[sizeof(di_args->path) - 1] = 0;
} else {
di_args->path[0] = '\0';
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index a38cfa4..42e3ecf 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -26,6 +26,7 @@
#include "backref.h"
#include "extent_io.h"
#include "check-integrity.h"
+#include "rcu-string.h"
/*
* This is only the first step towards a full-features scrub. It reads all
@@ -281,6 +282,7 @@ static int scrub_print_warning_inode(u64 inum, u64 offset,
u64 root, void *ctx)
struct inode_fs_paths *ipath = NULL;
struct btrfs_root *local_root;
struct btrfs_key root_key;
+ struct rcu_string *name;
root_key.objectid = root;
root_key.type = BTRFS_ROOT_ITEM_KEY;
@@ -319,24 +321,30 @@ static int scrub_print_warning_inode(u64 inum, u64
offset, u64 root, void *ctx)
* we deliberately ignore the bit ipath might have been too small to
* hold all of the paths here
*/
+ rcu_read_lock();
+ name = rcu_dereference(swarn->dev->name);
for (i = 0; i < ipath->fspath->elem_cnt; ++i)
printk(KERN_WARNING "btrfs: %s at logical %llu on dev "
"%s, sector %llu, root %llu, inode %llu, offset %llu, "
"length %llu, links %u (path: %s)\n", swarn->errstr,
- swarn->logical, swarn->dev->name,
+ swarn->logical, name->str,
(unsigned long long)swarn->sector, root, inum, offset,
min(isize - offset, (u64)PAGE_SIZE), nlink,
(char *)(unsigned long)ipath->fspath->val[i]);
+ rcu_read_unlock();
free_ipath(ipath);
return 0;
err:
+ rcu_read_lock();
+ name = rcu_dereference(swarn->dev->name);
printk(KERN_WARNING "btrfs: %s at logical %llu on dev "
"%s, sector %llu, root %llu, inode %llu, offset %llu: path "
"resolving failed with ret=%d\n", swarn->errstr,
- swarn->logical, swarn->dev->name,
+ swarn->logical, name->str,
(unsigned long long)swarn->sector, root, inum, offset, ret);
+ rcu_read_unlock();
free_ipath(ipath);
return 0;
@@ -388,16 +396,21 @@ static void scrub_print_warning(const char *errstr,
struct scrub_block *sblock)
if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
do {
+ struct rcu_string *name;
+
ret = tree_backref_for_extent(&ptr, eb, ei, item_size,
&ref_root, &ref_level);
+ rcu_read_lock();
+ name = rcu_dereference(dev->name);
printk(KERN_WARNING
"btrfs: %s at logical %llu on dev %s, "
"sector %llu: metadata %s (level %d) in tree "
- "%llu\n", errstr, swarn.logical, dev->name,
+ "%llu\n", errstr, swarn.logical, name->str,
(unsigned long long)swarn.sector,
ref_level ? "node" : "leaf",
ret < 0 ? -1 : ref_level,
ret < 0 ? -1 : ref_root);
+ rcu_read_unlock();
} while (ret != 1);
} else {
swarn.path = path;
@@ -577,12 +590,18 @@ out:
if (trans && !IS_ERR(trans))
btrfs_end_transaction(trans, fixup->root);
if (uncorrectable) {
+ struct rcu_string *name;
+
spin_lock(&sdev->stat_lock);
++sdev->stat.uncorrectable_errors;
spin_unlock(&sdev->stat_lock);
+
+ rcu_read_lock();
+ name = rcu_dereference(sdev->dev->name);
printk_ratelimited(KERN_ERR
"btrfs: unable to fixup (nodatasum) error at logical
%llu on dev %s\n",
- (unsigned long long)fixup->logical, sdev->dev->name);
+ (unsigned long long)fixup->logical, name->str);
+ rcu_read_unlock();
}
btrfs_free_path(path);
@@ -610,6 +629,7 @@ static int scrub_handle_errored_block(struct scrub_block
*sblock_to_check)
{
struct scrub_dev *sdev = sblock_to_check->sdev;
struct btrfs_fs_info *fs_info;
+ struct rcu_string *name;
u64 length;
u64 logical;
u64 generation;
@@ -936,18 +956,25 @@ corrected_error:
spin_lock(&sdev->stat_lock);
sdev->stat.corrected_errors++;
spin_unlock(&sdev->stat_lock);
+ rcu_read_lock();
+ name = rcu_dereference(sdev->dev->name);
printk_ratelimited(KERN_ERR
"btrfs: fixed up error at logical %llu on dev
%s\n",
- (unsigned long long)logical, sdev->dev->name);
+ (unsigned long long)logical, name->str);
+ rcu_read_unlock();
}
} else {
did_not_correct_error:
spin_lock(&sdev->stat_lock);
sdev->stat.uncorrectable_errors++;
spin_unlock(&sdev->stat_lock);
+ rcu_read_lock();
+ name = rcu_dereference(sdev->dev->name);
printk_ratelimited(KERN_ERR
"btrfs: unable to fixup (regular) error at logical %llu
on dev %s\n",
- (unsigned long long)logical, sdev->dev->name);
+ (unsigned long long)logical, name->str);
+ rcu_read_unlock();
+
}
out:
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 7782020..1eaa495 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -35,6 +35,7 @@
#include "volumes.h"
#include "async-thread.h"
#include "check-integrity.h"
+#include "rcu-string.h"
static int init_first_rw_device(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
@@ -64,7 +65,7 @@ static void free_fs_devices(struct btrfs_fs_devices
*fs_devices)
device = list_entry(fs_devices->devices.next,
struct btrfs_device, dev_list);
list_del(&device->dev_list);
- kfree(device->name);
+ rcu_string_free(device->name);
kfree(device);
}
kfree(fs_devices);
@@ -334,8 +335,8 @@ static noinline int device_list_add(const char *path,
{
struct btrfs_device *device;
struct btrfs_fs_devices *fs_devices;
+ struct rcu_string *name;
u64 found_transid = btrfs_super_generation(disk_super);
- char *name;
fs_devices = find_fsid(disk_super->fsid);
if (!fs_devices) {
@@ -369,11 +370,13 @@ static noinline int device_list_add(const char *path,
memcpy(device->uuid, disk_super->dev_item.uuid,
BTRFS_UUID_SIZE);
spin_lock_init(&device->io_lock);
- device->name = kstrdup(path, GFP_NOFS);
- if (!device->name) {
+
+ name = rcu_string_strdup(path, GFP_NOFS);
+ if (!name) {
kfree(device);
return -ENOMEM;
}
+ rcu_assign_pointer(device->name, name);
INIT_LIST_HEAD(&device->dev_alloc_list);
/* init readahead state */
@@ -390,12 +393,12 @@ static noinline int device_list_add(const char *path,
device->fs_devices = fs_devices;
fs_devices->num_devices++;
- } else if (!device->name || strcmp(device->name, path)) {
- name = kstrdup(path, GFP_NOFS);
+ } else if (!device->name || strcmp(device->name->str, path)) {
+ name = rcu_string_strdup(path, GFP_NOFS);
if (!name)
return -ENOMEM;
- kfree(device->name);
- device->name = name;
+ rcu_string_free(device->name);
+ rcu_assign_pointer(device->name, name);
if (device->missing) {
fs_devices->missing_devices--;
device->missing = 0;
@@ -415,6 +418,7 @@ static struct btrfs_fs_devices *clone_fs_devices(struct
btrfs_fs_devices *orig)
struct btrfs_fs_devices *fs_devices;
struct btrfs_device *device;
struct btrfs_device *orig_dev;
+ struct rcu_string *name;
fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
if (!fs_devices)
@@ -434,11 +438,16 @@ static struct btrfs_fs_devices *clone_fs_devices(struct
btrfs_fs_devices *orig)
if (!device)
goto error;
- device->name = kstrdup(orig_dev->name, GFP_NOFS);
- if (!device->name) {
+ /*
+ * This is ok to do without rcu read locked because we hold the
+ * uuid mutex so nothing we touch in here is going to disappear.
+ */
+ name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
+ if (!name) {
kfree(device);
goto error;
}
+ rcu_assign_pointer(device->name, name);
device->devid = orig_dev->devid;
device->work.func = pending_bios_fn;
@@ -491,7 +500,7 @@ again:
}
list_del_init(&device->dev_list);
fs_devices->num_devices--;
- kfree(device->name);
+ rcu_string_free(device->name);
kfree(device);
}
@@ -516,7 +525,7 @@ static void __free_device(struct work_struct *work)
if (device->bdev)
blkdev_put(device->bdev, device->mode);
- kfree(device->name);
+ rcu_string_free(device->name);
kfree(device);
}
@@ -533,6 +542,7 @@ static void free_device(struct rcu_head *head)
static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
{
struct btrfs_device *device;
+ struct rcu_string *name;
if (--fs_devices->opened > 0)
return 0;
@@ -555,8 +565,11 @@ static int __btrfs_close_devices(struct btrfs_fs_devices
*fs_devices)
new_device = kmalloc(sizeof(*new_device), GFP_NOFS);
BUG_ON(!new_device); /* -ENOMEM */
memcpy(new_device, device, sizeof(*new_device));
- new_device->name = kstrdup(device->name, GFP_NOFS);
- BUG_ON(device->name && !new_device->name); /* -ENOMEM */
+
+ /* Safe because we are under uuid_mutex */
+ name = rcu_string_strdup(device->name->str, GFP_NOFS);
+ BUG_ON(device->name && !name); /* -ENOMEM */
+ rcu_assign_pointer(new_device->name, name);
new_device->bdev = NULL;
new_device->writeable = 0;
new_device->in_fs_metadata = 0;
@@ -621,9 +634,9 @@ static int __btrfs_open_devices(struct btrfs_fs_devices
*fs_devices,
if (!device->name)
continue;
- bdev = blkdev_get_by_path(device->name, flags, holder);
+ bdev = blkdev_get_by_path(device->name->str, flags, holder);
if (IS_ERR(bdev)) {
- printk(KERN_INFO "open %s failed\n", device->name);
+ printk(KERN_INFO "open %s failed\n", device->name->str);
goto error;
}
filemap_write_and_wait(bdev->bd_inode->i_mapping);
@@ -1632,6 +1645,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char
*device_path)
struct block_device *bdev;
struct list_head *devices;
struct super_block *sb = root->fs_info->sb;
+ struct rcu_string *name;
u64 total_bytes;
int seeding_dev = 0;
int ret = 0;
@@ -1671,23 +1685,24 @@ int btrfs_init_new_device(struct btrfs_root *root, char
*device_path)
goto error;
}
- device->name = kstrdup(device_path, GFP_NOFS);
- if (!device->name) {
+ name = rcu_string_strdup(device_path, GFP_NOFS);
+ if (!name) {
kfree(device);
ret = -ENOMEM;
goto error;
}
+ rcu_assign_pointer(device->name, name);
ret = find_next_devid(root, &device->devid);
if (ret) {
- kfree(device->name);
+ rcu_string_free(device->name);
kfree(device);
goto error;
}
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans)) {
- kfree(device->name);
+ rcu_string_free(device->name);
kfree(device);
ret = PTR_ERR(trans);
goto error;
@@ -1796,7 +1811,7 @@ error_trans:
unlock_chunks(root);
btrfs_abort_transaction(trans, root, ret);
btrfs_end_transaction(trans, root);
- kfree(device->name);
+ rcu_string_free(device->name);
kfree(device);
error:
blkdev_put(bdev, FMODE_EXCL);
@@ -4204,10 +4219,17 @@ int btrfs_map_bio(struct btrfs_root *root, int rw,
struct bio *bio,
bio->bi_sector = bbio->stripes[dev_nr].physical >> 9;
dev = bbio->stripes[dev_nr].dev;
if (dev && dev->bdev && (rw != WRITE || dev->writeable)) {
+#ifdef DEBUG
+ struct rcu_string *name;
+
+ rcu_read_lock();
+ name = rcu_dereference(dev->name);
pr_debug("btrfs_map_bio: rw %d, secor=%llu, dev=%lu "
"(%s id %llu), size=%u\n", rw,
(u64)bio->bi_sector, (u_long)dev->bdev->bd_dev,
- dev->name, dev->devid, bio->bi_size);
+ name->str, dev->devid, bio->bi_size);
+ rcu_read_unlock();
+#endif
bio->bi_bdev = dev->bdev;
if (async_submit)
schedule_bio(root, dev, rw, bio);
@@ -4694,8 +4716,13 @@ int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
key.offset = device->devid;
ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
if (ret) {
+ struct rcu_string *name;
+
+ rcu_read_lock();
+ name = rcu_dereference(device->name);
printk(KERN_WARNING "btrfs: no dev_stats entry found
for device %s (devid %llu) (OK on first mount after mkfs)\n",
- device->name, (unsigned long long)device->devid);
+ name->str, (unsigned long long)device->devid);
+ rcu_read_unlock();
__btrfs_reset_dev_stats(device);
device->dev_stats_valid = 1;
btrfs_release_path(path);
@@ -4736,6 +4763,7 @@ static int update_dev_stat_item(struct btrfs_trans_handle
*trans,
struct btrfs_key key;
struct extent_buffer *eb;
struct btrfs_dev_stats_item *ptr;
+ struct rcu_string *name;
int ret;
int i;
@@ -4747,8 +4775,11 @@ static int update_dev_stat_item(struct
btrfs_trans_handle *trans,
BUG_ON(!path);
ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
if (ret < 0) {
+ rcu_read_lock();
+ name = rcu_dereference(device->name);
printk(KERN_WARNING "btrfs: error %d while searching for
dev_stats item for device %s!\n",
- ret, device->name);
+ ret, name->str);
+ rcu_read_unlock();
goto out;
}
@@ -4757,8 +4788,11 @@ static int update_dev_stat_item(struct
btrfs_trans_handle *trans,
/* need to delete old one and insert a new one */
ret = btrfs_del_item(trans, dev_root, path);
if (ret != 0) {
+ rcu_read_lock();
+ name = rcu_dereference(device->name);
printk(KERN_WARNING "btrfs: delete too small dev_stats
item for device %s failed %d!\n",
- device->name, ret);
+ name->str, ret);
+ rcu_read_unlock();
goto out;
}
ret = 1;
@@ -4770,8 +4804,11 @@ static int update_dev_stat_item(struct
btrfs_trans_handle *trans,
ret = btrfs_insert_empty_item(trans, dev_root, path,
&key, sizeof(*ptr));
if (ret < 0) {
+ rcu_read_lock();
+ name = rcu_dereference(device->name);
printk(KERN_WARNING "btrfs: insert dev_stats item for
device %s failed %d!\n",
- device->name, ret);
+ name->str, ret);
+ rcu_read_unlock();
goto out;
}
}
@@ -4821,11 +4858,14 @@ void btrfs_dev_stat_inc_and_print(struct btrfs_device
*dev, int index)
void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
{
+ struct rcu_string *name;
if (!dev->dev_stats_valid)
return;
+ rcu_read_lock();
+ name = rcu_dereference(dev->name);
printk_ratelimited(KERN_ERR
"btrfs: bdev %s errs: wr %u, rd %u, flush %u,
corrupt %u, gen %u\n",
- dev->name,
+ name->str,
btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
@@ -4833,17 +4873,23 @@ void btrfs_dev_stat_print_on_error(struct btrfs_device
*dev)
BTRFS_DEV_STAT_CORRUPTION_ERRS),
btrfs_dev_stat_read(dev,
BTRFS_DEV_STAT_GENERATION_ERRS));
+ rcu_read_unlock();
}
static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
{
+ struct rcu_string *name;
+
+ rcu_read_lock();
+ name = rcu_dereference(dev->name);
printk(KERN_INFO "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt
%u, gen %u\n",
- dev->name,
+ name->str,
btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
+ rcu_read_unlock();
}
int btrfs_get_dev_stats(struct btrfs_root *root,
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 3406a88..74366f2 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -58,7 +58,7 @@ struct btrfs_device {
/* the mode sent to blkdev_get */
fmode_t mode;
- char *name;
+ struct rcu_string *name;
/* the internal btrfs device id */
u64 devid;
--
1.7.7.6
--
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