diff options
Diffstat (limited to 'fs/buffer.c')
| -rw-r--r-- | fs/buffer.c | 39 |
1 files changed, 20 insertions, 19 deletions
diff --git a/fs/buffer.c b/fs/buffer.c index d1f1b54d3108..1ad674fd348c 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -180,7 +180,7 @@ int fsync_bdev(struct block_device *bdev) * freeze_bdev -- lock a filesystem and force it into a consistent state * @bdev: blockdevice to lock * - * This takes the block device bd_mount_mutex to make sure no new mounts + * This takes the block device bd_mount_sem to make sure no new mounts * 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. @@ -189,7 +189,7 @@ struct super_block *freeze_bdev(struct block_device *bdev) { struct super_block *sb; - mutex_lock(&bdev->bd_mount_mutex); + down(&bdev->bd_mount_sem); sb = get_super(bdev); if (sb && !(sb->s_flags & MS_RDONLY)) { sb->s_frozen = SB_FREEZE_WRITE; @@ -231,7 +231,7 @@ void thaw_bdev(struct block_device *bdev, struct super_block *sb) drop_super(sb); } - mutex_unlock(&bdev->bd_mount_mutex); + up(&bdev->bd_mount_sem); } EXPORT_SYMBOL(thaw_bdev); @@ -2844,23 +2844,24 @@ int try_to_free_buffers(struct page *page) spin_lock(&mapping->private_lock); ret = drop_buffers(page, &buffers_to_free); + + /* + * If the filesystem writes its buffers by hand (eg ext3) + * then we can have clean buffers against a dirty page. We + * clean the page here; otherwise the VM will never notice + * that the filesystem did any IO at all. + * + * Also, during truncate, discard_buffer will have marked all + * the page's buffers clean. We discover that here and clean + * the page also. + * + * private_lock must be held over this entire operation in order + * to synchronise against __set_page_dirty_buffers and prevent the + * dirty bit from being lost. + */ + if (ret) + cancel_dirty_page(page, PAGE_CACHE_SIZE); spin_unlock(&mapping->private_lock); - if (ret) { - /* - * If the filesystem writes its buffers by hand (eg ext3) - * then we can have clean buffers against a dirty page. We - * clean the page here; otherwise later reattachment of buffers - * could encounter a non-uptodate page, which is unresolvable. - * This only applies in the rare case where try_to_free_buffers - * succeeds but the page is not freed. - * - * Also, during truncate, discard_buffer will have marked all - * the page's buffers clean. We discover that here and clean - * the page also. - */ - if (test_clear_page_dirty(page)) - task_io_account_cancelled_write(PAGE_CACHE_SIZE); - } out: if (buffers_to_free) { struct buffer_head *bh = buffers_to_free; |