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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-18 18:50:12 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-18 18:50:12 +0000
commit8665bd53f2f2e27e5511d90428cb3f60e6d0ce15 (patch)
tree8d58900dc0ebd4a3011f92c128d2fe45bc7c4bf2 /block/bdev.c
parentAdding debian version 6.7.12-1. (diff)
downloadlinux-8665bd53f2f2e27e5511d90428cb3f60e6d0ce15.tar.xz
linux-8665bd53f2f2e27e5511d90428cb3f60e6d0ce15.zip
Merging upstream version 6.8.9.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'block/bdev.c')
-rw-r--r--block/bdev.c287
1 files changed, 170 insertions, 117 deletions
diff --git a/block/bdev.c b/block/bdev.c
index 750aec178b..812872cdc0 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -30,6 +30,9 @@
#include "../fs/internal.h"
#include "blk.h"
+/* Should we allow writing to mounted block devices? */
+static bool bdev_allow_write_mounted = IS_ENABLED(CONFIG_BLK_DEV_WRITE_MOUNTED);
+
struct bdev_inode {
struct block_device bdev;
struct inode vfs_inode;
@@ -207,85 +210,88 @@ int sync_blockdev_range(struct block_device *bdev, loff_t lstart, loff_t lend)
EXPORT_SYMBOL(sync_blockdev_range);
/**
- * freeze_bdev - lock a filesystem and force it into a consistent state
+ * bdev_freeze - 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
+ * freeze requests arrive simultaneously. It counts up in bdev_freeze() and
+ * count down in bdev_thaw(). When it becomes 0, thaw_bdev() will unfreeze
* actually.
+ *
+ * Return: On success zero is returned, negative error code on failure.
*/
-int freeze_bdev(struct block_device *bdev)
+int bdev_freeze(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, FREEZE_HOLDER_USERSPACE);
- else
- error = freeze_super(sb, FREEZE_HOLDER_USERSPACE);
- deactivate_super(sb);
- if (error) {
- bdev->bd_fsfreeze_count--;
- goto done;
+ if (atomic_inc_return(&bdev->bd_fsfreeze_count) > 1) {
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+ return 0;
}
- bdev->bd_fsfreeze_sb = sb;
-sync:
- sync_blockdev(bdev);
-done:
+ mutex_lock(&bdev->bd_holder_lock);
+ if (bdev->bd_holder_ops && bdev->bd_holder_ops->freeze) {
+ error = bdev->bd_holder_ops->freeze(bdev);
+ lockdep_assert_not_held(&bdev->bd_holder_lock);
+ } else {
+ mutex_unlock(&bdev->bd_holder_lock);
+ error = sync_blockdev(bdev);
+ }
+
+ if (error)
+ atomic_dec(&bdev->bd_fsfreeze_count);
+
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return error;
}
-EXPORT_SYMBOL(freeze_bdev);
+EXPORT_SYMBOL(bdev_freeze);
/**
- * thaw_bdev - unlock filesystem
+ * bdev_thaw - unlock filesystem
* @bdev: blockdevice to unlock
*
- * Unlocks the filesystem and marks it writeable again after freeze_bdev().
+ * Unlocks the filesystem and marks it writeable again after bdev_freeze().
+ *
+ * Return: On success zero is returned, negative error code on failure.
*/
-int thaw_bdev(struct block_device *bdev)
+int bdev_thaw(struct block_device *bdev)
{
- struct super_block *sb;
- int error = -EINVAL;
+ int error = -EINVAL, nr_freeze;
mutex_lock(&bdev->bd_fsfreeze_mutex);
- if (!bdev->bd_fsfreeze_count)
+
+ /*
+ * If this returns < 0 it means that @bd_fsfreeze_count was
+ * already 0 and no decrement was performed.
+ */
+ nr_freeze = atomic_dec_if_positive(&bdev->bd_fsfreeze_count);
+ if (nr_freeze < 0)
goto out;
error = 0;
- if (--bdev->bd_fsfreeze_count > 0)
+ if (nr_freeze > 0)
goto out;
- sb = bdev->bd_fsfreeze_sb;
- if (!sb)
- goto out;
+ mutex_lock(&bdev->bd_holder_lock);
+ if (bdev->bd_holder_ops && bdev->bd_holder_ops->thaw) {
+ error = bdev->bd_holder_ops->thaw(bdev);
+ lockdep_assert_not_held(&bdev->bd_holder_lock);
+ } else {
+ mutex_unlock(&bdev->bd_holder_lock);
+ }
- if (sb->s_op->thaw_super)
- error = sb->s_op->thaw_super(sb, FREEZE_HOLDER_USERSPACE);
- else
- error = thaw_super(sb, FREEZE_HOLDER_USERSPACE);
if (error)
- bdev->bd_fsfreeze_count++;
- else
- bdev->bd_fsfreeze_sb = NULL;
+ atomic_inc(&bdev->bd_fsfreeze_count);
out:
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return error;
}
-EXPORT_SYMBOL(thaw_bdev);
+EXPORT_SYMBOL(bdev_thaw);
/*
* pseudo-fs
@@ -633,6 +639,14 @@ static void blkdev_flush_mapping(struct block_device *bdev)
bdev_write_inode(bdev);
}
+static void blkdev_put_whole(struct block_device *bdev)
+{
+ if (atomic_dec_and_test(&bdev->bd_openers))
+ blkdev_flush_mapping(bdev);
+ if (bdev->bd_disk->fops->release)
+ bdev->bd_disk->fops->release(bdev->bd_disk);
+}
+
static int blkdev_get_whole(struct block_device *bdev, blk_mode_t mode)
{
struct gendisk *disk = bdev->bd_disk;
@@ -651,20 +665,21 @@ static int blkdev_get_whole(struct block_device *bdev, blk_mode_t mode)
if (!atomic_read(&bdev->bd_openers))
set_init_blocksize(bdev);
- if (test_bit(GD_NEED_PART_SCAN, &disk->state))
- bdev_disk_changed(disk, false);
atomic_inc(&bdev->bd_openers);
+ if (test_bit(GD_NEED_PART_SCAN, &disk->state)) {
+ /*
+ * Only return scanning errors if we are called from contexts
+ * that explicitly want them, e.g. the BLKRRPART ioctl.
+ */
+ ret = bdev_disk_changed(disk, false);
+ if (ret && (mode & BLK_OPEN_STRICT_SCAN)) {
+ blkdev_put_whole(bdev);
+ return ret;
+ }
+ }
return 0;
}
-static void blkdev_put_whole(struct block_device *bdev)
-{
- if (atomic_dec_and_test(&bdev->bd_openers))
- blkdev_flush_mapping(bdev);
- if (bdev->bd_disk->fops->release)
- bdev->bd_disk->fops->release(bdev->bd_disk);
-}
-
static int blkdev_get_part(struct block_device *part, blk_mode_t mode)
{
struct gendisk *disk = part->bd_disk;
@@ -729,9 +744,60 @@ void blkdev_put_no_open(struct block_device *bdev)
{
put_device(&bdev->bd_device);
}
-
+
+static bool bdev_writes_blocked(struct block_device *bdev)
+{
+ return bdev->bd_writers < 0;
+}
+
+static void bdev_block_writes(struct block_device *bdev)
+{
+ bdev->bd_writers--;
+}
+
+static void bdev_unblock_writes(struct block_device *bdev)
+{
+ bdev->bd_writers++;
+}
+
+static bool bdev_may_open(struct block_device *bdev, blk_mode_t mode)
+{
+ if (bdev_allow_write_mounted)
+ return true;
+ /* Writes blocked? */
+ if (mode & BLK_OPEN_WRITE && bdev_writes_blocked(bdev))
+ return false;
+ if (mode & BLK_OPEN_RESTRICT_WRITES && bdev->bd_writers > 0)
+ return false;
+ return true;
+}
+
+static void bdev_claim_write_access(struct block_device *bdev, blk_mode_t mode)
+{
+ if (bdev_allow_write_mounted)
+ return;
+
+ /* Claim exclusive or shared write access. */
+ if (mode & BLK_OPEN_RESTRICT_WRITES)
+ bdev_block_writes(bdev);
+ else if (mode & BLK_OPEN_WRITE)
+ bdev->bd_writers++;
+}
+
+static void bdev_yield_write_access(struct block_device *bdev, blk_mode_t mode)
+{
+ if (bdev_allow_write_mounted)
+ return;
+
+ /* Yield exclusive or shared write access. */
+ if (mode & BLK_OPEN_RESTRICT_WRITES)
+ bdev_unblock_writes(bdev);
+ else if (mode & BLK_OPEN_WRITE)
+ bdev->bd_writers--;
+}
+
/**
- * blkdev_get_by_dev - open a block device by device number
+ * bdev_open_by_dev - open a block device by device number
* @dev: device number of block device to open
* @mode: open mode (BLK_OPEN_*)
* @holder: exclusive holder identifier
@@ -743,32 +809,46 @@ void blkdev_put_no_open(struct block_device *bdev)
*
* 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().
+ * number. Everything else should use bdev_open_by_path().
*
* CONTEXT:
* Might sleep.
*
* RETURNS:
- * Reference to the block_device on success, ERR_PTR(-errno) on failure.
+ * Handle with a reference to the block_device on success, ERR_PTR(-errno) on
+ * failure.
*/
-struct block_device *blkdev_get_by_dev(dev_t dev, blk_mode_t mode, void *holder,
- const struct blk_holder_ops *hops)
+struct bdev_handle *bdev_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
+ const struct blk_holder_ops *hops)
{
- bool unblock_events = true;
+ struct bdev_handle *handle = kmalloc(sizeof(struct bdev_handle),
+ GFP_KERNEL);
struct block_device *bdev;
+ bool unblock_events = true;
struct gendisk *disk;
int ret;
+ if (!handle)
+ return ERR_PTR(-ENOMEM);
+
ret = devcgroup_check_permission(DEVCG_DEV_BLOCK,
MAJOR(dev), MINOR(dev),
((mode & BLK_OPEN_READ) ? DEVCG_ACC_READ : 0) |
((mode & BLK_OPEN_WRITE) ? DEVCG_ACC_WRITE : 0));
if (ret)
- return ERR_PTR(ret);
+ goto free_handle;
+
+ /* Blocking writes requires exclusive opener */
+ if (mode & BLK_OPEN_RESTRICT_WRITES && !holder) {
+ ret = -EINVAL;
+ goto free_handle;
+ }
bdev = blkdev_get_no_open(dev);
- if (!bdev)
- return ERR_PTR(-ENXIO);
+ if (!bdev) {
+ ret = -ENXIO;
+ goto free_handle;
+ }
disk = bdev->bd_disk;
if (holder) {
@@ -791,12 +871,16 @@ struct block_device *blkdev_get_by_dev(dev_t dev, blk_mode_t mode, void *holder,
goto abort_claiming;
if (!try_module_get(disk->fops->owner))
goto abort_claiming;
+ ret = -EBUSY;
+ if (!bdev_may_open(bdev, mode))
+ goto put_module;
if (bdev_is_partition(bdev))
ret = blkdev_get_part(bdev, mode);
else
ret = blkdev_get_whole(bdev, mode);
if (ret)
goto put_module;
+ bdev_claim_write_access(bdev, mode);
if (holder) {
bd_finish_claiming(bdev, holder, hops);
@@ -817,7 +901,10 @@ struct block_device *blkdev_get_by_dev(dev_t dev, blk_mode_t mode, void *holder,
if (unblock_events)
disk_unblock_events(disk);
- return bdev;
+ handle->bdev = bdev;
+ handle->holder = holder;
+ handle->mode = mode;
+ return handle;
put_module:
module_put(disk->fops->owner);
abort_claiming:
@@ -827,34 +914,14 @@ abort_claiming:
disk_unblock_events(disk);
put_blkdev:
blkdev_put_no_open(bdev);
+free_handle:
+ kfree(handle);
return ERR_PTR(ret);
}
-EXPORT_SYMBOL(blkdev_get_by_dev);
-
-struct bdev_handle *bdev_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
- const struct blk_holder_ops *hops)
-{
- struct bdev_handle *handle = kmalloc(sizeof(*handle), GFP_KERNEL);
- struct block_device *bdev;
-
- if (!handle)
- return ERR_PTR(-ENOMEM);
- bdev = blkdev_get_by_dev(dev, mode, holder, hops);
- if (IS_ERR(bdev)) {
- kfree(handle);
- return ERR_CAST(bdev);
- }
- handle->bdev = bdev;
- handle->holder = holder;
- if (holder)
- mode |= BLK_OPEN_EXCL;
- handle->mode = mode;
- return handle;
-}
EXPORT_SYMBOL(bdev_open_by_dev);
/**
- * blkdev_get_by_path - open a block device by name
+ * bdev_open_by_path - open a block device by name
* @path: path to the block device to open
* @mode: open mode (BLK_OPEN_*)
* @holder: exclusive holder identifier
@@ -868,29 +935,9 @@ EXPORT_SYMBOL(bdev_open_by_dev);
* Might sleep.
*
* RETURNS:
- * Reference to the block_device on success, ERR_PTR(-errno) on failure.
+ * Handle with a reference to the block_device on success, ERR_PTR(-errno) on
+ * failure.
*/
-struct block_device *blkdev_get_by_path(const char *path, blk_mode_t mode,
- void *holder, const struct blk_holder_ops *hops)
-{
- 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, hops);
- if (!IS_ERR(bdev) && (mode & BLK_OPEN_WRITE) && bdev_read_only(bdev)) {
- blkdev_put(bdev, holder);
- return ERR_PTR(-EACCES);
- }
-
- return bdev;
-}
-EXPORT_SYMBOL(blkdev_get_by_path);
-
struct bdev_handle *bdev_open_by_path(const char *path, blk_mode_t mode,
void *holder, const struct blk_holder_ops *hops)
{
@@ -913,8 +960,9 @@ struct bdev_handle *bdev_open_by_path(const char *path, blk_mode_t mode,
}
EXPORT_SYMBOL(bdev_open_by_path);
-void blkdev_put(struct block_device *bdev, void *holder)
+void bdev_release(struct bdev_handle *handle)
{
+ struct block_device *bdev = handle->bdev;
struct gendisk *disk = bdev->bd_disk;
/*
@@ -928,8 +976,10 @@ void blkdev_put(struct block_device *bdev, void *holder)
sync_blockdev(bdev);
mutex_lock(&disk->open_mutex);
- if (holder)
- bd_end_claim(bdev, holder);
+ bdev_yield_write_access(bdev, handle->mode);
+
+ if (handle->holder)
+ bd_end_claim(bdev, handle->holder);
/*
* Trigger event checking and tell drivers to flush MEDIA_CHANGE
@@ -946,12 +996,6 @@ void blkdev_put(struct block_device *bdev, void *holder)
module_put(disk->fops->owner);
blkdev_put_no_open(bdev);
-}
-EXPORT_SYMBOL(blkdev_put);
-
-void bdev_release(struct bdev_handle *handle)
-{
- blkdev_put(handle->bdev, handle->holder);
kfree(handle);
}
EXPORT_SYMBOL(bdev_release);
@@ -1102,3 +1146,12 @@ void bdev_statx_dioalign(struct inode *inode, struct kstat *stat)
blkdev_put_no_open(bdev);
}
+
+static int __init setup_bdev_allow_write_mounted(char *str)
+{
+ if (kstrtobool(str, &bdev_allow_write_mounted))
+ pr_warn("Invalid option string for bdev_allow_write_mounted:"
+ " '%s'\n", str);
+ return 1;
+}
+__setup("bdev_allow_write_mounted=", setup_bdev_allow_write_mounted);