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-rw-r--r--fs/buffer.c104
1 files changed, 80 insertions, 24 deletions
diff --git a/fs/buffer.c b/fs/buffer.c
index c26da785938a..891e1c78e4f1 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -203,10 +203,25 @@ int fsync_bdev(struct block_device *bdev)
* happen on bdev until thaw_bdev() is called.
* 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.
*/
struct super_block *freeze_bdev(struct block_device *bdev)
{
struct super_block *sb;
+ int error = 0;
+
+ mutex_lock(&bdev->bd_fsfreeze_mutex);
+ if (bdev->bd_fsfreeze_count > 0) {
+ bdev->bd_fsfreeze_count++;
+ sb = get_super(bdev);
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+ return sb;
+ }
+ bdev->bd_fsfreeze_count++;
down(&bdev->bd_mount_sem);
sb = get_super(bdev);
@@ -221,11 +236,24 @@ struct super_block *freeze_bdev(struct block_device *bdev)
sync_blockdev(sb->s_bdev);
- if (sb->s_op->write_super_lockfs)
- sb->s_op->write_super_lockfs(sb);
+ if (sb->s_op->freeze_fs) {
+ error = sb->s_op->freeze_fs(sb);
+ if (error) {
+ printk(KERN_ERR
+ "VFS:Filesystem freeze failed\n");
+ sb->s_frozen = SB_UNFROZEN;
+ drop_super(sb);
+ up(&bdev->bd_mount_sem);
+ bdev->bd_fsfreeze_count--;
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+ return ERR_PTR(error);
+ }
+ }
}
sync_blockdev(bdev);
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+
return sb; /* thaw_bdev releases s->s_umount and bd_mount_sem */
}
EXPORT_SYMBOL(freeze_bdev);
@@ -237,20 +265,48 @@ EXPORT_SYMBOL(freeze_bdev);
*
* Unlocks the filesystem and marks it writeable again after freeze_bdev().
*/
-void thaw_bdev(struct block_device *bdev, struct super_block *sb)
+int thaw_bdev(struct block_device *bdev, struct super_block *sb)
{
+ int error = 0;
+
+ mutex_lock(&bdev->bd_fsfreeze_mutex);
+ if (!bdev->bd_fsfreeze_count) {
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+ return -EINVAL;
+ }
+
+ bdev->bd_fsfreeze_count--;
+ if (bdev->bd_fsfreeze_count > 0) {
+ if (sb)
+ drop_super(sb);
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+ return 0;
+ }
+
if (sb) {
BUG_ON(sb->s_bdev != bdev);
-
- if (sb->s_op->unlockfs)
- sb->s_op->unlockfs(sb);
- sb->s_frozen = SB_UNFROZEN;
- smp_wmb();
- wake_up(&sb->s_wait_unfrozen);
+ if (!(sb->s_flags & MS_RDONLY)) {
+ if (sb->s_op->unfreeze_fs) {
+ error = sb->s_op->unfreeze_fs(sb);
+ if (error) {
+ printk(KERN_ERR
+ "VFS:Filesystem thaw failed\n");
+ sb->s_frozen = SB_FREEZE_TRANS;
+ bdev->bd_fsfreeze_count++;
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+ return error;
+ }
+ }
+ sb->s_frozen = SB_UNFROZEN;
+ smp_wmb();
+ wake_up(&sb->s_wait_unfrozen);
+ }
drop_super(sb);
}
up(&bdev->bd_mount_sem);
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+ return 0;
}
EXPORT_SYMBOL(thaw_bdev);
@@ -704,15 +760,9 @@ EXPORT_SYMBOL(mark_buffer_dirty_inode);
* If warn is true, then emit a warning if the page is not uptodate and has
* not been truncated.
*/
-static int __set_page_dirty(struct page *page,
+static void __set_page_dirty(struct page *page,
struct address_space *mapping, int warn)
{
- if (unlikely(!mapping))
- return !TestSetPageDirty(page);
-
- if (TestSetPageDirty(page))
- return 0;
-
spin_lock_irq(&mapping->tree_lock);
if (page->mapping) { /* Race with truncate? */
WARN_ON_ONCE(warn && !PageUptodate(page));
@@ -721,6 +771,7 @@ static int __set_page_dirty(struct page *page,
__inc_zone_page_state(page, NR_FILE_DIRTY);
__inc_bdi_stat(mapping->backing_dev_info,
BDI_RECLAIMABLE);
+ task_dirty_inc(current);
task_io_account_write(PAGE_CACHE_SIZE);
}
radix_tree_tag_set(&mapping->page_tree,
@@ -728,8 +779,6 @@ static int __set_page_dirty(struct page *page,
}
spin_unlock_irq(&mapping->tree_lock);
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
-
- return 1;
}
/*
@@ -759,6 +808,7 @@ static int __set_page_dirty(struct page *page,
*/
int __set_page_dirty_buffers(struct page *page)
{
+ int newly_dirty;
struct address_space *mapping = page_mapping(page);
if (unlikely(!mapping))
@@ -774,9 +824,12 @@ int __set_page_dirty_buffers(struct page *page)
bh = bh->b_this_page;
} while (bh != head);
}
+ newly_dirty = !TestSetPageDirty(page);
spin_unlock(&mapping->private_lock);
- return __set_page_dirty(page, mapping, 1);
+ if (newly_dirty)
+ __set_page_dirty(page, mapping, 1);
+ return newly_dirty;
}
EXPORT_SYMBOL(__set_page_dirty_buffers);
@@ -1205,8 +1258,11 @@ void mark_buffer_dirty(struct buffer_head *bh)
return;
}
- if (!test_set_buffer_dirty(bh))
- __set_page_dirty(bh->b_page, page_mapping(bh->b_page), 0);
+ if (!test_set_buffer_dirty(bh)) {
+ struct page *page = bh->b_page;
+ if (!TestSetPageDirty(page))
+ __set_page_dirty(page, page_mapping(page), 0);
+ }
}
/*
@@ -2632,7 +2688,7 @@ int nobh_write_end(struct file *file, struct address_space *mapping,
struct buffer_head *bh;
BUG_ON(fsdata != NULL && page_has_buffers(page));
- if (unlikely(copied < len) && !page_has_buffers(page))
+ if (unlikely(copied < len) && head)
attach_nobh_buffers(page, head);
if (page_has_buffers(page))
return generic_write_end(file, mapping, pos, len,
@@ -3052,7 +3108,7 @@ int sync_dirty_buffer(struct buffer_head *bh)
if (test_clear_buffer_dirty(bh)) {
get_bh(bh);
bh->b_end_io = end_buffer_write_sync;
- ret = submit_bh(WRITE_SYNC, bh);
+ ret = submit_bh(WRITE, bh);
wait_on_buffer(bh);
if (buffer_eopnotsupp(bh)) {
clear_buffer_eopnotsupp(bh);
@@ -3187,7 +3243,7 @@ void block_sync_page(struct page *page)
* Use of bdflush() is deprecated and will be removed in a future kernel.
* The `pdflush' kernel threads fully replace bdflush daemons and this call.
*/
-asmlinkage long sys_bdflush(int func, long data)
+SYSCALL_DEFINE2(bdflush, int, func, long, data)
{
static int msg_count;
generated by cgit v1.2.3 (git 2.39.0) at 2024-10-19 18:35:07 +0300