From e7848683ae7ded0a4a8964122a47da9104a98337 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 12 Jun 2012 16:20:32 +0200 Subject: btrfs: Push mnt_want_write() outside of i_mutex When mnt_want_write() starts to handle freezing it will get a full lock semantics requiring proper lock ordering. So push mnt_want_write() call consistently outside of i_mutex. CC: Chris Mason CC: linux-btrfs@vger.kernel.org Signed-off-by: Jan Kara Signed-off-by: Al Viro --- fs/btrfs/ioctl.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) (limited to 'fs/btrfs') diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 1e9f6c019ad..cd93eb530b7 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -193,6 +193,10 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg) if (!inode_owner_or_capable(inode)) return -EACCES; + ret = mnt_want_write_file(file); + if (ret) + return ret; + mutex_lock(&inode->i_mutex); ip_oldflags = ip->flags; @@ -207,10 +211,6 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg) } } - ret = mnt_want_write_file(file); - if (ret) - goto out_unlock; - if (flags & FS_SYNC_FL) ip->flags |= BTRFS_INODE_SYNC; else @@ -273,9 +273,9 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg) inode->i_flags = i_oldflags; } - mnt_drop_write_file(file); out_unlock: mutex_unlock(&inode->i_mutex); + mnt_drop_write_file(file); return ret; } @@ -641,6 +641,10 @@ static noinline int btrfs_mksubvol(struct path *parent, struct dentry *dentry; int error; + error = mnt_want_write(parent->mnt); + if (error) + return error; + mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT); dentry = lookup_one_len(name, parent->dentry, namelen); @@ -652,13 +656,9 @@ static noinline int btrfs_mksubvol(struct path *parent, if (dentry->d_inode) goto out_dput; - error = mnt_want_write(parent->mnt); - if (error) - goto out_dput; - error = btrfs_may_create(dir, dentry); if (error) - goto out_drop_write; + goto out_dput; down_read(&BTRFS_I(dir)->root->fs_info->subvol_sem); @@ -676,12 +676,11 @@ static noinline int btrfs_mksubvol(struct path *parent, fsnotify_mkdir(dir, dentry); out_up_read: up_read(&BTRFS_I(dir)->root->fs_info->subvol_sem); -out_drop_write: - mnt_drop_write(parent->mnt); out_dput: dput(dentry); out_unlock: mutex_unlock(&dir->i_mutex); + mnt_drop_write(parent->mnt); return error; } -- cgit v1.2.3-18-g5258 From b2b5ef5c8e89f19b68c174bf246f3ca212dbf0bc Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 12 Jun 2012 16:20:45 +0200 Subject: btrfs: Convert to new freezing mechanism We convert btrfs_file_aio_write() to use new freeze check. We also add proper freeze protection to btrfs_page_mkwrite(). We also add freeze protection to the transaction mechanism to avoid starting transactions on frozen filesystem. At minimum this is necessary to stop iput() of unlinked file to change frozen filesystem during truncation. Checks in cleaner_kthread() and transaction_kthread() can be safely removed since btrfs_freeze() will lock the mutexes and thus block the threads (and they shouldn't have anything to do anyway). CC: linux-btrfs@vger.kernel.org CC: Chris Mason Signed-off-by: Jan Kara Signed-off-by: Al Viro --- fs/btrfs/disk-io.c | 3 --- fs/btrfs/file.c | 3 ++- fs/btrfs/inode.c | 6 +++++- fs/btrfs/transaction.c | 7 +++++++ 4 files changed, 14 insertions(+), 5 deletions(-) (limited to 'fs/btrfs') diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 2936ca49b3b..20c49b16b75 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1533,8 +1533,6 @@ static int cleaner_kthread(void *arg) struct btrfs_root *root = arg; do { - vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE); - if (!(root->fs_info->sb->s_flags & MS_RDONLY) && mutex_trylock(&root->fs_info->cleaner_mutex)) { btrfs_run_delayed_iputs(root); @@ -1566,7 +1564,6 @@ static int transaction_kthread(void *arg) do { cannot_commit = false; delay = HZ * 30; - vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE); mutex_lock(&root->fs_info->transaction_kthread_mutex); spin_lock(&root->fs_info->trans_lock); diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 9aa01ec2138..5caf285c6e4 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1379,7 +1379,7 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb, ssize_t err = 0; size_t count, ocount; - vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); + sb_start_write(inode->i_sb); mutex_lock(&inode->i_mutex); @@ -1469,6 +1469,7 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb, num_written = err; } out: + sb_end_write(inode->i_sb); current->backing_dev_info = NULL; return num_written ? num_written : err; } diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index fb8d671d00e..f4d901786b3 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -6620,6 +6620,7 @@ int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) u64 page_start; u64 page_end; + sb_start_pagefault(inode->i_sb); ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE); if (!ret) { ret = file_update_time(vma->vm_file); @@ -6709,12 +6710,15 @@ again: unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS); out_unlock: - if (!ret) + if (!ret) { + sb_end_pagefault(inode->i_sb); return VM_FAULT_LOCKED; + } unlock_page(page); out: btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE); out_noreserve: + sb_end_pagefault(inode->i_sb); return ret; } diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index b72b068183e..fa67ba51516 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -329,6 +329,8 @@ again: if (!h) return ERR_PTR(-ENOMEM); + sb_start_intwrite(root->fs_info->sb); + if (may_wait_transaction(root, type)) wait_current_trans(root); @@ -339,6 +341,7 @@ again: } while (ret == -EBUSY); if (ret < 0) { + sb_end_intwrite(root->fs_info->sb); kmem_cache_free(btrfs_trans_handle_cachep, h); return ERR_PTR(ret); } @@ -528,6 +531,8 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, count++; } + sb_end_intwrite(root->fs_info->sb); + if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) && should_end_transaction(trans, root)) { trans->transaction->blocked = 1; @@ -1517,6 +1522,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, put_transaction(cur_trans); put_transaction(cur_trans); + sb_end_intwrite(root->fs_info->sb); + trace_btrfs_transaction_commit(root); btrfs_scrub_continue(root); -- cgit v1.2.3-18-g5258