diff --git a/fs/fuse/dax.c b/fs/fuse/dax.c index c21305409191..efc1a8ef5639 100644 --- a/fs/fuse/dax.c +++ b/fs/fuse/dax.c @@ -495,6 +495,47 @@ static const struct iomap_ops fuse_iomap_ops = { .iomap_end = fuse_iomap_end, }; +static void fuse_wait_dax_page(struct inode *inode) +{ + struct fuse_inode *fi = get_fuse_inode(inode); + + up_write(&fi->i_mmap_sem); + schedule(); + down_write(&fi->i_mmap_sem); +} + +/* Should be called with fi->i_mmap_sem lock held exclusively */ +static int __fuse_dax_break_layouts(struct inode *inode, bool *retry, + loff_t start, loff_t end) +{ + struct page *page; + + page = dax_layout_busy_page_range(inode->i_mapping, start, end); + if (!page) + return 0; + + *retry = true; + return ___wait_var_event(&page->_refcount, + atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE, + 0, 0, fuse_wait_dax_page(inode)); +} + +/* dmap_end == 0 leads to unmapping of whole file */ +int fuse_dax_break_layouts(struct inode *inode, u64 dmap_start, + u64 dmap_end) +{ + bool retry; + int ret; + + do { + retry = false; + ret = __fuse_dax_break_layouts(inode, &retry, dmap_start, + dmap_end); + } while (ret == 0 && retry); + + return ret; +} + ssize_t fuse_dax_read_iter(struct kiocb *iocb, struct iov_iter *to) { struct inode *inode = file_inode(iocb->ki_filp); @@ -596,10 +637,18 @@ static vm_fault_t __fuse_dax_fault(struct vm_fault *vmf, if (write) sb_start_pagefault(sb); + /* + * We need to serialize against not only truncate but also against + * fuse dax memory range reclaim. While a range is being reclaimed, + * we do not want any read/write/mmap to make progress and try + * to populate page cache or access memory we are trying to free. + */ + down_read(&get_fuse_inode(inode)->i_mmap_sem); ret = dax_iomap_fault(vmf, pe_size, &pfn, NULL, &fuse_iomap_ops); if (ret & VM_FAULT_NEEDDSYNC) ret = dax_finish_sync_fault(vmf, pe_size, pfn); + up_read(&get_fuse_inode(inode)->i_mmap_sem); if (write) sb_end_pagefault(sb); diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index 26f028bc760b..c4a01290aec6 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -1501,6 +1501,7 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr, loff_t oldsize; int err; bool trust_local_cmtime = is_wb && S_ISREG(inode->i_mode); + bool fault_blocked = false; if (!fc->default_permissions) attr->ia_valid |= ATTR_FORCE; @@ -1509,6 +1510,22 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr, if (err) return err; + if (attr->ia_valid & ATTR_SIZE) { + if (WARN_ON(!S_ISREG(inode->i_mode))) + return -EIO; + is_truncate = true; + } + + if (FUSE_IS_DAX(inode) && is_truncate) { + down_write(&fi->i_mmap_sem); + fault_blocked = true; + err = fuse_dax_break_layouts(inode, 0, 0); + if (err) { + up_write(&fi->i_mmap_sem); + return err; + } + } + if (attr->ia_valid & ATTR_OPEN) { /* This is coming from open(..., ... | O_TRUNC); */ WARN_ON(!(attr->ia_valid & ATTR_SIZE)); @@ -1521,17 +1538,11 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr, */ i_size_write(inode, 0); truncate_pagecache(inode, 0); - return 0; + goto out; } file = NULL; } - if (attr->ia_valid & ATTR_SIZE) { - if (WARN_ON(!S_ISREG(inode->i_mode))) - return -EIO; - is_truncate = true; - } - /* Flush dirty data/metadata before non-truncate SETATTR */ if (is_wb && S_ISREG(inode->i_mode) && attr->ia_valid & @@ -1614,6 +1625,10 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr, } clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); +out: + if (fault_blocked) + up_write(&fi->i_mmap_sem); + return 0; error: @@ -1621,6 +1636,9 @@ error: fuse_release_nowrite(inode); clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); + + if (fault_blocked) + up_write(&fi->i_mmap_sem); return err; } diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 2aac787464bc..172a0b1aa634 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -221,22 +221,34 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir) bool is_wb_truncate = (file->f_flags & O_TRUNC) && fc->atomic_o_trunc && fc->writeback_cache; + bool dax_truncate = (file->f_flags & O_TRUNC) && + fc->atomic_o_trunc && FUSE_IS_DAX(inode); err = generic_file_open(inode, file); if (err) return err; - if (is_wb_truncate) { + if (is_wb_truncate || dax_truncate) { inode_lock(inode); fuse_set_nowrite(inode); } - err = fuse_do_open(fc, get_node_id(inode), file, isdir); + if (dax_truncate) { + down_write(&get_fuse_inode(inode)->i_mmap_sem); + err = fuse_dax_break_layouts(inode, 0, 0); + if (err) + goto out; + } + err = fuse_do_open(fc, get_node_id(inode), file, isdir); if (!err) fuse_finish_open(inode, file); - if (is_wb_truncate) { +out: + if (dax_truncate) + up_write(&get_fuse_inode(inode)->i_mmap_sem); + + if (is_wb_truncate | dax_truncate) { fuse_release_nowrite(inode); inode_unlock(inode); } @@ -3221,6 +3233,8 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset, bool lock_inode = !(mode & FALLOC_FL_KEEP_SIZE) || (mode & FALLOC_FL_PUNCH_HOLE); + bool block_faults = FUSE_IS_DAX(inode) && lock_inode; + if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) return -EOPNOTSUPP; @@ -3229,6 +3243,13 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset, if (lock_inode) { inode_lock(inode); + if (block_faults) { + down_write(&fi->i_mmap_sem); + err = fuse_dax_break_layouts(inode, 0, 0); + if (err) + goto out; + } + if (mode & FALLOC_FL_PUNCH_HOLE) { loff_t endbyte = offset + length - 1; @@ -3278,6 +3299,9 @@ out: if (!(mode & FALLOC_FL_KEEP_SIZE)) clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); + if (block_faults) + up_write(&fi->i_mmap_sem); + if (lock_inode) inode_unlock(inode); diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 2d2bdd596194..32c935f1e1b0 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -149,6 +149,13 @@ struct fuse_inode { /** Lock to protect write related fields */ spinlock_t lock; + /** + * Can't take inode lock in fault path (leads to circular dependency). + * Introduce another semaphore which can be taken in fault path and + * then other filesystem paths can take this to block faults. + */ + struct rw_semaphore i_mmap_sem; + #ifdef CONFIG_FUSE_DAX /* * Dax specific inode data @@ -1116,6 +1123,7 @@ void fuse_free_conn(struct fuse_conn *fc); ssize_t fuse_dax_read_iter(struct kiocb *iocb, struct iov_iter *to); ssize_t fuse_dax_write_iter(struct kiocb *iocb, struct iov_iter *from); int fuse_dax_mmap(struct file *file, struct vm_area_struct *vma); +int fuse_dax_break_layouts(struct inode *inode, u64 dmap_start, u64 dmap_end); int fuse_dax_conn_alloc(struct fuse_conn *fc, struct dax_device *dax_dev); void fuse_dax_conn_free(struct fuse_conn *fc); bool fuse_dax_inode_alloc(struct super_block *sb, struct fuse_inode *fi); diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index cab4239bd78a..d252237219bf 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -85,6 +85,7 @@ static struct inode *fuse_alloc_inode(struct super_block *sb) fi->orig_ino = 0; fi->state = 0; mutex_init(&fi->mutex); + init_rwsem(&fi->i_mmap_sem); spin_lock_init(&fi->lock); fi->forget = fuse_alloc_forget(); if (!fi->forget)