| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Vivek Goyal | 4973 | 85.68% | 7 | 11.67% |
| Miklos Szeredi | 333 | 5.74% | 17 | 28.33% |
| Stefan Hajnoczi | 233 | 4.01% | 4 | 6.67% |
| Jeffle Xu | 123 | 2.12% | 6 | 10.00% |
| Jan Kara | 29 | 0.50% | 1 | 1.67% |
| Matthew Wilcox | 17 | 0.29% | 3 | 5.00% |
| Tejun Heo | 16 | 0.28% | 2 | 3.33% |
| Anand V. Avati | 16 | 0.28% | 1 | 1.67% |
| Max Reitz | 10 | 0.17% | 1 | 1.67% |
| Niels de Vos | 9 | 0.16% | 1 | 1.67% |
| Hangyu Hua | 6 | 0.10% | 1 | 1.67% |
| Darrick J. Wong | 6 | 0.10% | 2 | 3.33% |
| Pavel Emelyanov | 5 | 0.09% | 1 | 1.67% |
| Suren Baghdasaryan | 4 | 0.07% | 1 | 1.67% |
| Li Wang | 4 | 0.07% | 1 | 1.67% |
| Zheng Yongjun | 3 | 0.05% | 1 | 1.67% |
| David Howells | 3 | 0.05% | 1 | 1.67% |
| Brian Foster | 2 | 0.03% | 1 | 1.67% |
| Jane Chu | 2 | 0.03% | 1 | 1.67% |
| Yan Zheng | 2 | 0.03% | 1 | 1.67% |
| Ira Weiny | 2 | 0.03% | 1 | 1.67% |
| Al Viro | 2 | 0.03% | 1 | 1.67% |
| Khazhismel Kumykov | 1 | 0.02% | 1 | 1.67% |
| Christoph Hellwig | 1 | 0.02% | 1 | 1.67% |
| Maxim Patlasov | 1 | 0.02% | 1 | 1.67% |
| Anatol Pomozov | 1 | 0.02% | 1 | 1.67% |
| Total | 5804 | 60 |
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// SPDX-License-Identifier: GPL-2.0 /* * dax: direct host memory access * Copyright (C) 2020 Red Hat, Inc. */ #include "fuse_i.h" #include <linux/delay.h> #include <linux/dax.h> #include <linux/uio.h> #include <linux/pagemap.h> #include <linux/pfn_t.h> #include <linux/iomap.h> #include <linux/interval_tree.h> /* * Default memory range size. A power of 2 so it agrees with common FUSE_INIT * map_alignment values 4KB and 64KB. */ #define FUSE_DAX_SHIFT 21 #define FUSE_DAX_SZ (1 << FUSE_DAX_SHIFT) #define FUSE_DAX_PAGES (FUSE_DAX_SZ / PAGE_SIZE) /* Number of ranges reclaimer will try to free in one invocation */ #define FUSE_DAX_RECLAIM_CHUNK (10) /* * Dax memory reclaim threshold in percetage of total ranges. When free * number of free ranges drops below this threshold, reclaim can trigger * Default is 20% */ #define FUSE_DAX_RECLAIM_THRESHOLD (20) /** Translation information for file offsets to DAX window offsets */ struct fuse_dax_mapping { /* Pointer to inode where this memory range is mapped */ struct inode *inode; /* Will connect in fcd->free_ranges to keep track of free memory */ struct list_head list; /* For interval tree in file/inode */ struct interval_tree_node itn; /* Will connect in fc->busy_ranges to keep track busy memory */ struct list_head busy_list; /** Position in DAX window */ u64 window_offset; /** Length of mapping, in bytes */ loff_t length; /* Is this mapping read-only or read-write */ bool writable; /* reference count when the mapping is used by dax iomap. */ refcount_t refcnt; }; /* Per-inode dax map */ struct fuse_inode_dax { /* Semaphore to protect modifications to the dmap tree */ struct rw_semaphore sem; /* Sorted rb tree of struct fuse_dax_mapping elements */ struct rb_root_cached tree; unsigned long nr; }; struct fuse_conn_dax { /* DAX device */ struct dax_device *dev; /* Lock protecting accessess to members of this structure */ spinlock_t lock; /* List of memory ranges which are busy */ unsigned long nr_busy_ranges; struct list_head busy_ranges; /* Worker to free up memory ranges */ struct delayed_work free_work; /* Wait queue for a dax range to become free */ wait_queue_head_t range_waitq; /* DAX Window Free Ranges */ long nr_free_ranges; struct list_head free_ranges; unsigned long nr_ranges; }; static inline struct fuse_dax_mapping * node_to_dmap(struct interval_tree_node *node) { if (!node) return NULL; return container_of(node, struct fuse_dax_mapping, itn); } static struct fuse_dax_mapping * alloc_dax_mapping_reclaim(struct fuse_conn_dax *fcd, struct inode *inode); static void __kick_dmap_free_worker(struct fuse_conn_dax *fcd, unsigned long delay_ms) { unsigned long free_threshold; /* If number of free ranges are below threshold, start reclaim */ free_threshold = max_t(unsigned long, fcd->nr_ranges * FUSE_DAX_RECLAIM_THRESHOLD / 100, 1); if (fcd->nr_free_ranges < free_threshold) queue_delayed_work(system_long_wq, &fcd->free_work, msecs_to_jiffies(delay_ms)); } static void kick_dmap_free_worker(struct fuse_conn_dax *fcd, unsigned long delay_ms) { spin_lock(&fcd->lock); __kick_dmap_free_worker(fcd, delay_ms); spin_unlock(&fcd->lock); } static struct fuse_dax_mapping *alloc_dax_mapping(struct fuse_conn_dax *fcd) { struct fuse_dax_mapping *dmap; spin_lock(&fcd->lock); dmap = list_first_entry_or_null(&fcd->free_ranges, struct fuse_dax_mapping, list); if (dmap) { list_del_init(&dmap->list); WARN_ON(fcd->nr_free_ranges <= 0); fcd->nr_free_ranges--; } __kick_dmap_free_worker(fcd, 0); spin_unlock(&fcd->lock); return dmap; } /* This assumes fcd->lock is held */ static void __dmap_remove_busy_list(struct fuse_conn_dax *fcd, struct fuse_dax_mapping *dmap) { list_del_init(&dmap->busy_list); WARN_ON(fcd->nr_busy_ranges == 0); fcd->nr_busy_ranges--; } static void dmap_remove_busy_list(struct fuse_conn_dax *fcd, struct fuse_dax_mapping *dmap) { spin_lock(&fcd->lock); __dmap_remove_busy_list(fcd, dmap); spin_unlock(&fcd->lock); } /* This assumes fcd->lock is held */ static void __dmap_add_to_free_pool(struct fuse_conn_dax *fcd, struct fuse_dax_mapping *dmap) { list_add_tail(&dmap->list, &fcd->free_ranges); fcd->nr_free_ranges++; wake_up(&fcd->range_waitq); } static void dmap_add_to_free_pool(struct fuse_conn_dax *fcd, struct fuse_dax_mapping *dmap) { /* Return fuse_dax_mapping to free list */ spin_lock(&fcd->lock); __dmap_add_to_free_pool(fcd, dmap); spin_unlock(&fcd->lock); } static int fuse_setup_one_mapping(struct inode *inode, unsigned long start_idx, struct fuse_dax_mapping *dmap, bool writable, bool upgrade) { struct fuse_mount *fm = get_fuse_mount(inode); struct fuse_conn_dax *fcd = fm->fc->dax; struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_setupmapping_in inarg; loff_t offset = start_idx << FUSE_DAX_SHIFT; FUSE_ARGS(args); ssize_t err; WARN_ON(fcd->nr_free_ranges < 0); /* Ask fuse daemon to setup mapping */ memset(&inarg, 0, sizeof(inarg)); inarg.foffset = offset; inarg.fh = -1; inarg.moffset = dmap->window_offset; inarg.len = FUSE_DAX_SZ; inarg.flags |= FUSE_SETUPMAPPING_FLAG_READ; if (writable) inarg.flags |= FUSE_SETUPMAPPING_FLAG_WRITE; args.opcode = FUSE_SETUPMAPPING; args.nodeid = fi->nodeid; args.in_numargs = 1; args.in_args[0].size = sizeof(inarg); args.in_args[0].value = &inarg; err = fuse_simple_request(fm, &args); if (err < 0) return err; dmap->writable = writable; if (!upgrade) { /* * We don't take a reference on inode. inode is valid right now * and when inode is going away, cleanup logic should first * cleanup dmap entries. */ dmap->inode = inode; dmap->itn.start = dmap->itn.last = start_idx; /* Protected by fi->dax->sem */ interval_tree_insert(&dmap->itn, &fi->dax->tree); fi->dax->nr++; spin_lock(&fcd->lock); list_add_tail(&dmap->busy_list, &fcd->busy_ranges); fcd->nr_busy_ranges++; spin_unlock(&fcd->lock); } return 0; } static int fuse_send_removemapping(struct inode *inode, struct fuse_removemapping_in *inargp, struct fuse_removemapping_one *remove_one) { struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_mount *fm = get_fuse_mount(inode); FUSE_ARGS(args); args.opcode = FUSE_REMOVEMAPPING; args.nodeid = fi->nodeid; args.in_numargs = 2; args.in_args[0].size = sizeof(*inargp); args.in_args[0].value = inargp; args.in_args[1].size = inargp->count * sizeof(*remove_one); args.in_args[1].value = remove_one; return fuse_simple_request(fm, &args); } static int dmap_removemapping_list(struct inode *inode, unsigned int num, struct list_head *to_remove) { struct fuse_removemapping_one *remove_one, *ptr; struct fuse_removemapping_in inarg; struct fuse_dax_mapping *dmap; int ret, i = 0, nr_alloc; nr_alloc = min_t(unsigned int, num, FUSE_REMOVEMAPPING_MAX_ENTRY); remove_one = kmalloc_array(nr_alloc, sizeof(*remove_one), GFP_NOFS); if (!remove_one) return -ENOMEM; ptr = remove_one; list_for_each_entry(dmap, to_remove, list) { ptr->moffset = dmap->window_offset; ptr->len = dmap->length; ptr++; i++; num--; if (i >= nr_alloc || num == 0) { memset(&inarg, 0, sizeof(inarg)); inarg.count = i; ret = fuse_send_removemapping(inode, &inarg, remove_one); if (ret) goto out; ptr = remove_one; i = 0; } } out: kfree(remove_one); return ret; } /* * Cleanup dmap entry and add back to free list. This should be called with * fcd->lock held. */ static void dmap_reinit_add_to_free_pool(struct fuse_conn_dax *fcd, struct fuse_dax_mapping *dmap) { pr_debug("fuse: freeing memory range start_idx=0x%lx end_idx=0x%lx window_offset=0x%llx length=0x%llx\n", dmap->itn.start, dmap->itn.last, dmap->window_offset, dmap->length); __dmap_remove_busy_list(fcd, dmap); dmap->inode = NULL; dmap->itn.start = dmap->itn.last = 0; __dmap_add_to_free_pool(fcd, dmap); } /* * Free inode dmap entries whose range falls inside [start, end]. * Does not take any locks. At this point of time it should only be * called from evict_inode() path where we know all dmap entries can be * reclaimed. */ static void inode_reclaim_dmap_range(struct fuse_conn_dax *fcd, struct inode *inode, loff_t start, loff_t end) { struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_dax_mapping *dmap, *n; int err, num = 0; LIST_HEAD(to_remove); unsigned long start_idx = start >> FUSE_DAX_SHIFT; unsigned long end_idx = end >> FUSE_DAX_SHIFT; struct interval_tree_node *node; while (1) { node = interval_tree_iter_first(&fi->dax->tree, start_idx, end_idx); if (!node) break; dmap = node_to_dmap(node); /* inode is going away. There should not be any users of dmap */ WARN_ON(refcount_read(&dmap->refcnt) > 1); interval_tree_remove(&dmap->itn, &fi->dax->tree); num++; list_add(&dmap->list, &to_remove); } /* Nothing to remove */ if (list_empty(&to_remove)) return; WARN_ON(fi->dax->nr < num); fi->dax->nr -= num; err = dmap_removemapping_list(inode, num, &to_remove); if (err && err != -ENOTCONN) { pr_warn("Failed to removemappings. start=0x%llx end=0x%llx\n", start, end); } spin_lock(&fcd->lock); list_for_each_entry_safe(dmap, n, &to_remove, list) { list_del_init(&dmap->list); dmap_reinit_add_to_free_pool(fcd, dmap); } spin_unlock(&fcd->lock); } static int dmap_removemapping_one(struct inode *inode, struct fuse_dax_mapping *dmap) { struct fuse_removemapping_one forget_one; struct fuse_removemapping_in inarg; memset(&inarg, 0, sizeof(inarg)); inarg.count = 1; memset(&forget_one, 0, sizeof(forget_one)); forget_one.moffset = dmap->window_offset; forget_one.len = dmap->length; return fuse_send_removemapping(inode, &inarg, &forget_one); } /* * It is called from evict_inode() and by that time inode is going away. So * this function does not take any locks like fi->dax->sem for traversing * that fuse inode interval tree. If that lock is taken then lock validator * complains of deadlock situation w.r.t fs_reclaim lock. */ void fuse_dax_inode_cleanup(struct inode *inode) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); /* * fuse_evict_inode() has already called truncate_inode_pages_final() * before we arrive here. So we should not have to worry about any * pages/exception entries still associated with inode. */ inode_reclaim_dmap_range(fc->dax, inode, 0, -1); WARN_ON(fi->dax->nr); } static void fuse_fill_iomap_hole(struct iomap *iomap, loff_t length) { iomap->addr = IOMAP_NULL_ADDR; iomap->length = length; iomap->type = IOMAP_HOLE; } static void fuse_fill_iomap(struct inode *inode, loff_t pos, loff_t length, struct iomap *iomap, struct fuse_dax_mapping *dmap, unsigned int flags) { loff_t offset, len; loff_t i_size = i_size_read(inode); offset = pos - (dmap->itn.start << FUSE_DAX_SHIFT); len = min(length, dmap->length - offset); /* If length is beyond end of file, truncate further */ if (pos + len > i_size) len = i_size - pos; if (len > 0) { iomap->addr = dmap->window_offset + offset; iomap->length = len; if (flags & IOMAP_FAULT) iomap->length = ALIGN(len, PAGE_SIZE); iomap->type = IOMAP_MAPPED; /* * increace refcnt so that reclaim code knows this dmap is in * use. This assumes fi->dax->sem mutex is held either * shared/exclusive. */ refcount_inc(&dmap->refcnt); /* iomap->private should be NULL */ WARN_ON_ONCE(iomap->private); iomap->private = dmap; } else { /* Mapping beyond end of file is hole */ fuse_fill_iomap_hole(iomap, length); } } static int fuse_setup_new_dax_mapping(struct inode *inode, loff_t pos, loff_t length, unsigned int flags, struct iomap *iomap) { struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_conn_dax *fcd = fc->dax; struct fuse_dax_mapping *dmap, *alloc_dmap = NULL; int ret; bool writable = flags & IOMAP_WRITE; unsigned long start_idx = pos >> FUSE_DAX_SHIFT; struct interval_tree_node *node; /* * Can't do inline reclaim in fault path. We call * dax_layout_busy_page() before we free a range. And * fuse_wait_dax_page() drops mapping->invalidate_lock and requires it. * In fault path we enter with mapping->invalidate_lock held and can't * drop it. Also in fault path we hold mapping->invalidate_lock shared * and not exclusive, so that creates further issues with * fuse_wait_dax_page(). Hence return -EAGAIN and fuse_dax_fault() * will wait for a memory range to become free and retry. */ if (flags & IOMAP_FAULT) { alloc_dmap = alloc_dax_mapping(fcd); if (!alloc_dmap) return -EAGAIN; } else { alloc_dmap = alloc_dax_mapping_reclaim(fcd, inode); if (IS_ERR(alloc_dmap)) return PTR_ERR(alloc_dmap); } /* If we are here, we should have memory allocated */ if (WARN_ON(!alloc_dmap)) return -EIO; /* * Take write lock so that only one caller can try to setup mapping * and other waits. */ down_write(&fi->dax->sem); /* * We dropped lock. Check again if somebody else setup * mapping already. */ node = interval_tree_iter_first(&fi->dax->tree, start_idx, start_idx); if (node) { dmap = node_to_dmap(node); fuse_fill_iomap(inode, pos, length, iomap, dmap, flags); dmap_add_to_free_pool(fcd, alloc_dmap); up_write(&fi->dax->sem); return 0; } /* Setup one mapping */ ret = fuse_setup_one_mapping(inode, pos >> FUSE_DAX_SHIFT, alloc_dmap, writable, false); if (ret < 0) { dmap_add_to_free_pool(fcd, alloc_dmap); up_write(&fi->dax->sem); return ret; } fuse_fill_iomap(inode, pos, length, iomap, alloc_dmap, flags); up_write(&fi->dax->sem); return 0; } static int fuse_upgrade_dax_mapping(struct inode *inode, loff_t pos, loff_t length, unsigned int flags, struct iomap *iomap) { struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_dax_mapping *dmap; int ret; unsigned long idx = pos >> FUSE_DAX_SHIFT; struct interval_tree_node *node; /* * Take exclusive lock so that only one caller can try to setup * mapping and others wait. */ down_write(&fi->dax->sem); node = interval_tree_iter_first(&fi->dax->tree, idx, idx); /* We are holding either inode lock or invalidate_lock, and that should * ensure that dmap can't be truncated. We are holding a reference * on dmap and that should make sure it can't be reclaimed. So dmap * should still be there in tree despite the fact we dropped and * re-acquired the fi->dax->sem lock. */ ret = -EIO; if (WARN_ON(!node)) goto out_err; dmap = node_to_dmap(node); /* We took an extra reference on dmap to make sure its not reclaimd. * Now we hold fi->dax->sem lock and that reference is not needed * anymore. Drop it. */ if (refcount_dec_and_test(&dmap->refcnt)) { /* refcount should not hit 0. This object only goes * away when fuse connection goes away */ WARN_ON_ONCE(1); } /* Maybe another thread already upgraded mapping while we were not * holding lock. */ if (dmap->writable) { ret = 0; goto out_fill_iomap; } ret = fuse_setup_one_mapping(inode, pos >> FUSE_DAX_SHIFT, dmap, true, true); if (ret < 0) goto out_err; out_fill_iomap: fuse_fill_iomap(inode, pos, length, iomap, dmap, flags); out_err: up_write(&fi->dax->sem); return ret; } /* This is just for DAX and the mapping is ephemeral, do not use it for other * purposes since there is no block device with a permanent mapping. */ static int fuse_iomap_begin(struct inode *inode, loff_t pos, loff_t length, unsigned int flags, struct iomap *iomap, struct iomap *srcmap) { struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_dax_mapping *dmap; bool writable = flags & IOMAP_WRITE; unsigned long start_idx = pos >> FUSE_DAX_SHIFT; struct interval_tree_node *node; /* We don't support FIEMAP */ if (WARN_ON(flags & IOMAP_REPORT)) return -EIO; iomap->offset = pos; iomap->flags = 0; iomap->bdev = NULL; iomap->dax_dev = fc->dax->dev; /* * Both read/write and mmap path can race here. So we need something * to make sure if we are setting up mapping, then other path waits * * For now, use a semaphore for this. It probably needs to be * optimized later. */ down_read(&fi->dax->sem); node = interval_tree_iter_first(&fi->dax->tree, start_idx, start_idx); if (node) { dmap = node_to_dmap(node); if (writable && !dmap->writable) { /* Upgrade read-only mapping to read-write. This will * require exclusive fi->dax->sem lock as we don't want * two threads to be trying to this simultaneously * for same dmap. So drop shared lock and acquire * exclusive lock. * * Before dropping fi->dax->sem lock, take reference * on dmap so that its not freed by range reclaim. */ refcount_inc(&dmap->refcnt); up_read(&fi->dax->sem); pr_debug("%s: Upgrading mapping at offset 0x%llx length 0x%llx\n", __func__, pos, length); return fuse_upgrade_dax_mapping(inode, pos, length, flags, iomap); } else { fuse_fill_iomap(inode, pos, length, iomap, dmap, flags); up_read(&fi->dax->sem); return 0; } } else { up_read(&fi->dax->sem); pr_debug("%s: no mapping at offset 0x%llx length 0x%llx\n", __func__, pos, length); if (pos >= i_size_read(inode)) goto iomap_hole; return fuse_setup_new_dax_mapping(inode, pos, length, flags, iomap); } /* * If read beyond end of file happens, fs code seems to return * it as hole */ iomap_hole: fuse_fill_iomap_hole(iomap, length); pr_debug("%s returning hole mapping. pos=0x%llx length_asked=0x%llx length_returned=0x%llx\n", __func__, pos, length, iomap->length); return 0; } static int fuse_iomap_end(struct inode *inode, loff_t pos, loff_t length, ssize_t written, unsigned int flags, struct iomap *iomap) { struct fuse_dax_mapping *dmap = iomap->private; if (dmap) { if (refcount_dec_and_test(&dmap->refcnt)) { /* refcount should not hit 0. This object only goes * away when fuse connection goes away */ WARN_ON_ONCE(1); } } /* DAX writes beyond end-of-file aren't handled using iomap, so the * file size is unchanged and there is nothing to do here. */ return 0; } static const struct iomap_ops fuse_iomap_ops = { .iomap_begin = fuse_iomap_begin, .iomap_end = fuse_iomap_end, }; static void fuse_wait_dax_page(struct inode *inode) { filemap_invalidate_unlock(inode->i_mapping); schedule(); filemap_invalidate_lock(inode->i_mapping); } /* Should be called with mapping->invalidate_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); ssize_t ret; if (iocb->ki_flags & IOCB_NOWAIT) { if (!inode_trylock_shared(inode)) return -EAGAIN; } else { inode_lock_shared(inode); } ret = dax_iomap_rw(iocb, to, &fuse_iomap_ops); inode_unlock_shared(inode); /* TODO file_accessed(iocb->f_filp) */ return ret; } static bool file_extending_write(struct kiocb *iocb, struct iov_iter *from) { struct inode *inode = file_inode(iocb->ki_filp); return (iov_iter_rw(from) == WRITE && ((iocb->ki_pos) >= i_size_read(inode) || (iocb->ki_pos + iov_iter_count(from) > i_size_read(inode)))); } static ssize_t fuse_dax_direct_write(struct kiocb *iocb, struct iov_iter *from) { struct inode *inode = file_inode(iocb->ki_filp); struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb); ssize_t ret; ret = fuse_direct_io(&io, from, &iocb->ki_pos, FUSE_DIO_WRITE); fuse_write_update_attr(inode, iocb->ki_pos, ret); return ret; } ssize_t fuse_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct inode *inode = file_inode(iocb->ki_filp); ssize_t ret; if (iocb->ki_flags & IOCB_NOWAIT) { if (!inode_trylock(inode)) return -EAGAIN; } else { inode_lock(inode); } ret = generic_write_checks(iocb, from); if (ret <= 0) goto out; ret = file_remove_privs(iocb->ki_filp); if (ret) goto out; /* TODO file_update_time() but we don't want metadata I/O */ /* Do not use dax for file extending writes as write and on * disk i_size increase are not atomic otherwise. */ if (file_extending_write(iocb, from)) ret = fuse_dax_direct_write(iocb, from); else ret = dax_iomap_rw(iocb, from, &fuse_iomap_ops); out: inode_unlock(inode); if (ret > 0) ret = generic_write_sync(iocb, ret); return ret; } static vm_fault_t __fuse_dax_fault(struct vm_fault *vmf, unsigned int order, bool write) { vm_fault_t ret; struct inode *inode = file_inode(vmf->vma->vm_file); struct super_block *sb = inode->i_sb; pfn_t pfn; int error = 0; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_conn_dax *fcd = fc->dax; bool retry = false; if (write) sb_start_pagefault(sb); retry: if (retry && !(fcd->nr_free_ranges > 0)) wait_event(fcd->range_waitq, (fcd->nr_free_ranges > 0)); /* * 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. */ filemap_invalidate_lock_shared(inode->i_mapping); ret = dax_iomap_fault(vmf, order, &pfn, &error, &fuse_iomap_ops); if ((ret & VM_FAULT_ERROR) && error == -EAGAIN) { error = 0; retry = true; filemap_invalidate_unlock_shared(inode->i_mapping); goto retry; } if (ret & VM_FAULT_NEEDDSYNC) ret = dax_finish_sync_fault(vmf, order, pfn); filemap_invalidate_unlock_shared(inode->i_mapping); if (write) sb_end_pagefault(sb); return ret; } static vm_fault_t fuse_dax_fault(struct vm_fault *vmf) { return __fuse_dax_fault(vmf, 0, vmf->flags & FAULT_FLAG_WRITE); } static vm_fault_t fuse_dax_huge_fault(struct vm_fault *vmf, unsigned int order) { return __fuse_dax_fault(vmf, order, vmf->flags & FAULT_FLAG_WRITE); } static vm_fault_t fuse_dax_page_mkwrite(struct vm_fault *vmf) { return __fuse_dax_fault(vmf, 0, true); } static vm_fault_t fuse_dax_pfn_mkwrite(struct vm_fault *vmf) { return __fuse_dax_fault(vmf, 0, true); } static const struct vm_operations_struct fuse_dax_vm_ops = { .fault = fuse_dax_fault, .huge_fault = fuse_dax_huge_fault, .page_mkwrite = fuse_dax_page_mkwrite, .pfn_mkwrite = fuse_dax_pfn_mkwrite, }; int fuse_dax_mmap(struct file *file, struct vm_area_struct *vma) { file_accessed(file); vma->vm_ops = &fuse_dax_vm_ops; vm_flags_set(vma, VM_MIXEDMAP | VM_HUGEPAGE); return 0; } static int dmap_writeback_invalidate(struct inode *inode, struct fuse_dax_mapping *dmap) { int ret; loff_t start_pos = dmap->itn.start << FUSE_DAX_SHIFT; loff_t end_pos = (start_pos + FUSE_DAX_SZ - 1); ret = filemap_fdatawrite_range(inode->i_mapping, start_pos, end_pos); if (ret) { pr_debug("fuse: filemap_fdatawrite_range() failed. err=%d start_pos=0x%llx, end_pos=0x%llx\n", ret, start_pos, end_pos); return ret; } ret = invalidate_inode_pages2_range(inode->i_mapping, start_pos >> PAGE_SHIFT, end_pos >> PAGE_SHIFT); if (ret) pr_debug("fuse: invalidate_inode_pages2_range() failed err=%d\n", ret); return ret; } static int reclaim_one_dmap_locked(struct inode *inode, struct fuse_dax_mapping *dmap) { int ret; struct fuse_inode *fi = get_fuse_inode(inode); /* * igrab() was done to make sure inode won't go under us, and this * further avoids the race with evict(). */ ret = dmap_writeback_invalidate(inode, dmap); if (ret) return ret; /* Remove dax mapping from inode interval tree now */ interval_tree_remove(&dmap->itn, &fi->dax->tree); fi->dax->nr--; /* It is possible that umount/shutdown has killed the fuse connection * and worker thread is trying to reclaim memory in parallel. Don't * warn in that case. */ ret = dmap_removemapping_one(inode, dmap); if (ret && ret != -ENOTCONN) { pr_warn("Failed to remove mapping. offset=0x%llx len=0x%llx ret=%d\n", dmap->window_offset, dmap->length, ret); } return 0; } /* Find first mapped dmap for an inode and return file offset. Caller needs * to hold fi->dax->sem lock either shared or exclusive. */ static struct fuse_dax_mapping *inode_lookup_first_dmap(struct inode *inode) { struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_dax_mapping *dmap; struct interval_tree_node *node; for (node = interval_tree_iter_first(&fi->dax->tree, 0, -1); node; node = interval_tree_iter_next(node, 0, -1)) { dmap = node_to_dmap(node); /* still in use. */ if (refcount_read(&dmap->refcnt) > 1) continue; return dmap; } return NULL; } /* * Find first mapping in the tree and free it and return it. Do not add * it back to free pool. */ static struct fuse_dax_mapping * inode_inline_reclaim_one_dmap(struct fuse_conn_dax *fcd, struct inode *inode, bool *retry) { struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_dax_mapping *dmap; u64 dmap_start, dmap_end; unsigned long start_idx; int ret; struct interval_tree_node *node; filemap_invalidate_lock(inode->i_mapping); /* Lookup a dmap and corresponding file offset to reclaim. */ down_read(&fi->dax->sem); dmap = inode_lookup_first_dmap(inode); if (dmap) { start_idx = dmap->itn.start; dmap_start = start_idx << FUSE_DAX_SHIFT; dmap_end = dmap_start + FUSE_DAX_SZ - 1; } up_read(&fi->dax->sem); if (!dmap) goto out_mmap_sem; /* * Make sure there are no references to inode pages using * get_user_pages() */ ret = fuse_dax_break_layouts(inode, dmap_start, dmap_end); if (ret) { pr_debug("fuse: fuse_dax_break_layouts() failed. err=%d\n", ret); dmap = ERR_PTR(ret); goto out_mmap_sem; } down_write(&fi->dax->sem); node = interval_tree_iter_first(&fi->dax->tree, start_idx, start_idx); /* Range already got reclaimed by somebody else */ if (!node) { if (retry) *retry = true; goto out_write_dmap_sem; } dmap = node_to_dmap(node); /* still in use. */ if (refcount_read(&dmap->refcnt) > 1) { dmap = NULL; if (retry) *retry = true; goto out_write_dmap_sem; } ret = reclaim_one_dmap_locked(inode, dmap); if (ret < 0) { dmap = ERR_PTR(ret); goto out_write_dmap_sem; } /* Clean up dmap. Do not add back to free list */ dmap_remove_busy_list(fcd, dmap); dmap->inode = NULL; dmap->itn.start = dmap->itn.last = 0; pr_debug("fuse: %s: inline reclaimed memory range. inode=%p, window_offset=0x%llx, length=0x%llx\n", __func__, inode, dmap->window_offset, dmap->length); out_write_dmap_sem: up_write(&fi->dax->sem); out_mmap_sem: filemap_invalidate_unlock(inode->i_mapping); return dmap; } static struct fuse_dax_mapping * alloc_dax_mapping_reclaim(struct fuse_conn_dax *fcd, struct inode *inode) { struct fuse_dax_mapping *dmap; struct fuse_inode *fi = get_fuse_inode(inode); while (1) { bool retry = false; dmap = alloc_dax_mapping(fcd); if (dmap) return dmap; dmap = inode_inline_reclaim_one_dmap(fcd, inode, &retry); /* * Either we got a mapping or it is an error, return in both * the cases. */ if (dmap) return dmap; /* If we could not reclaim a mapping because it * had a reference or some other temporary failure, * Try again. We want to give up inline reclaim only * if there is no range assigned to this node. Otherwise * if a deadlock is possible if we sleep with * mapping->invalidate_lock held and worker to free memory * can't make progress due to unavailability of * mapping->invalidate_lock. So sleep only if fi->dax->nr=0 */ if (retry) continue; /* * There are no mappings which can be reclaimed. Wait for one. * We are not holding fi->dax->sem. So it is possible * that range gets added now. But as we are not holding * mapping->invalidate_lock, worker should still be able to * free up a range and wake us up. */ if (!fi->dax->nr && !(fcd->nr_free_ranges > 0)) { if (wait_event_killable_exclusive(fcd->range_waitq, (fcd->nr_free_ranges > 0))) { return ERR_PTR(-EINTR); } } } } static int lookup_and_reclaim_dmap_locked(struct fuse_conn_dax *fcd, struct inode *inode, unsigned long start_idx) { int ret; struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_dax_mapping *dmap; struct interval_tree_node *node; /* Find fuse dax mapping at file offset inode. */ node = interval_tree_iter_first(&fi->dax->tree, start_idx, start_idx); /* Range already got cleaned up by somebody else */ if (!node) return 0; dmap = node_to_dmap(node); /* still in use. */ if (refcount_read(&dmap->refcnt) > 1) return 0; ret = reclaim_one_dmap_locked(inode, dmap); if (ret < 0) return ret; /* Cleanup dmap entry and add back to free list */ spin_lock(&fcd->lock); dmap_reinit_add_to_free_pool(fcd, dmap); spin_unlock(&fcd->lock); return ret; } /* * Free a range of memory. * Locking: * 1. Take mapping->invalidate_lock to block dax faults. * 2. Take fi->dax->sem to protect interval tree and also to make sure * read/write can not reuse a dmap which we might be freeing. */ static int lookup_and_reclaim_dmap(struct fuse_conn_dax *fcd, struct inode *inode, unsigned long start_idx, unsigned long end_idx) { int ret; struct fuse_inode *fi = get_fuse_inode(inode); loff_t dmap_start = start_idx << FUSE_DAX_SHIFT; loff_t dmap_end = (dmap_start + FUSE_DAX_SZ) - 1; filemap_invalidate_lock(inode->i_mapping); ret = fuse_dax_break_layouts(inode, dmap_start, dmap_end); if (ret) { pr_debug("virtio_fs: fuse_dax_break_layouts() failed. err=%d\n", ret); goto out_mmap_sem; } down_write(&fi->dax->sem); ret = lookup_and_reclaim_dmap_locked(fcd, inode, start_idx); up_write(&fi->dax->sem); out_mmap_sem: filemap_invalidate_unlock(inode->i_mapping); return ret; } static int try_to_free_dmap_chunks(struct fuse_conn_dax *fcd, unsigned long nr_to_free) { struct fuse_dax_mapping *dmap, *pos, *temp; int ret, nr_freed = 0; unsigned long start_idx = 0, end_idx = 0; struct inode *inode = NULL; /* Pick first busy range and free it for now*/ while (1) { if (nr_freed >= nr_to_free) break; dmap = NULL; spin_lock(&fcd->lock); if (!fcd->nr_busy_ranges) { spin_unlock(&fcd->lock); return 0; } list_for_each_entry_safe(pos, temp, &fcd->busy_ranges, busy_list) { /* skip this range if it's in use. */ if (refcount_read(&pos->refcnt) > 1) continue; inode = igrab(pos->inode); /* * This inode is going away. That will free * up all the ranges anyway, continue to * next range. */ if (!inode) continue; /* * Take this element off list and add it tail. If * this element can't be freed, it will help with * selecting new element in next iteration of loop. */ dmap = pos; list_move_tail(&dmap->busy_list, &fcd->busy_ranges); start_idx = end_idx = dmap->itn.start; break; } spin_unlock(&fcd->lock); if (!dmap) return 0; ret = lookup_and_reclaim_dmap(fcd, inode, start_idx, end_idx); iput(inode); if (ret) return ret; nr_freed++; } return 0; } static void fuse_dax_free_mem_worker(struct work_struct *work) { int ret; struct fuse_conn_dax *fcd = container_of(work, struct fuse_conn_dax, free_work.work); ret = try_to_free_dmap_chunks(fcd, FUSE_DAX_RECLAIM_CHUNK); if (ret) { pr_debug("fuse: try_to_free_dmap_chunks() failed with err=%d\n", ret); } /* If number of free ranges are still below threshold, requeue */ kick_dmap_free_worker(fcd, 1); } static void fuse_free_dax_mem_ranges(struct list_head *mem_list) { struct fuse_dax_mapping *range, *temp; /* Free All allocated elements */ list_for_each_entry_safe(range, temp, mem_list, list) { list_del(&range->list); if (!list_empty(&range->busy_list)) list_del(&range->busy_list); kfree(range); } } void fuse_dax_conn_free(struct fuse_conn *fc) { if (fc->dax) { fuse_free_dax_mem_ranges(&fc->dax->free_ranges); kfree(fc->dax); fc->dax = NULL; } } static int fuse_dax_mem_range_init(struct fuse_conn_dax *fcd) { long nr_pages, nr_ranges; struct fuse_dax_mapping *range; int ret, id; size_t dax_size = -1; unsigned long i; init_waitqueue_head(&fcd->range_waitq); INIT_LIST_HEAD(&fcd->free_ranges); INIT_LIST_HEAD(&fcd->busy_ranges); INIT_DELAYED_WORK(&fcd->free_work, fuse_dax_free_mem_worker); id = dax_read_lock(); nr_pages = dax_direct_access(fcd->dev, 0, PHYS_PFN(dax_size), DAX_ACCESS, NULL, NULL); dax_read_unlock(id); if (nr_pages < 0) { pr_debug("dax_direct_access() returned %ld\n", nr_pages); return nr_pages; } nr_ranges = nr_pages/FUSE_DAX_PAGES; pr_debug("%s: dax mapped %ld pages. nr_ranges=%ld\n", __func__, nr_pages, nr_ranges); for (i = 0; i < nr_ranges; i++) { range = kzalloc(sizeof(struct fuse_dax_mapping), GFP_KERNEL); ret = -ENOMEM; if (!range) goto out_err; /* TODO: This offset only works if virtio-fs driver is not * having some memory hidden at the beginning. This needs * better handling */ range->window_offset = i * FUSE_DAX_SZ; range->length = FUSE_DAX_SZ; INIT_LIST_HEAD(&range->busy_list); refcount_set(&range->refcnt, 1); list_add_tail(&range->list, &fcd->free_ranges); } fcd->nr_free_ranges = nr_ranges; fcd->nr_ranges = nr_ranges; return 0; out_err: /* Free All allocated elements */ fuse_free_dax_mem_ranges(&fcd->free_ranges); return ret; } int fuse_dax_conn_alloc(struct fuse_conn *fc, enum fuse_dax_mode dax_mode, struct dax_device *dax_dev) { struct fuse_conn_dax *fcd; int err; fc->dax_mode = dax_mode; if (!dax_dev) return 0; fcd = kzalloc(sizeof(*fcd), GFP_KERNEL); if (!fcd) return -ENOMEM; spin_lock_init(&fcd->lock); fcd->dev = dax_dev; err = fuse_dax_mem_range_init(fcd); if (err) { kfree(fcd); return err; } fc->dax = fcd; return 0; } bool fuse_dax_inode_alloc(struct super_block *sb, struct fuse_inode *fi) { struct fuse_conn *fc = get_fuse_conn_super(sb); fi->dax = NULL; if (fc->dax) { fi->dax = kzalloc(sizeof(*fi->dax), GFP_KERNEL_ACCOUNT); if (!fi->dax) return false; init_rwsem(&fi->dax->sem); fi->dax->tree = RB_ROOT_CACHED; } return true; } static const struct address_space_operations fuse_dax_file_aops = { .direct_IO = noop_direct_IO, .dirty_folio = noop_dirty_folio, }; static bool fuse_should_enable_dax(struct inode *inode, unsigned int flags) { struct fuse_conn *fc = get_fuse_conn(inode); enum fuse_dax_mode dax_mode = fc->dax_mode; if (dax_mode == FUSE_DAX_NEVER) return false; /* * fc->dax may be NULL in 'inode' mode when filesystem device doesn't * support DAX, in which case it will silently fallback to 'never' mode. */ if (!fc->dax) return false; if (dax_mode == FUSE_DAX_ALWAYS) return true; /* dax_mode is FUSE_DAX_INODE* */ return fc->inode_dax && (flags & FUSE_ATTR_DAX); } void fuse_dax_inode_init(struct inode *inode, unsigned int flags) { if (!fuse_should_enable_dax(inode, flags)) return; inode->i_flags |= S_DAX; inode->i_data.a_ops = &fuse_dax_file_aops; } void fuse_dax_dontcache(struct inode *inode, unsigned int flags) { struct fuse_conn *fc = get_fuse_conn(inode); if (fuse_is_inode_dax_mode(fc->dax_mode) && ((bool) IS_DAX(inode) != (bool) (flags & FUSE_ATTR_DAX))) d_mark_dontcache(inode); } bool fuse_dax_check_alignment(struct fuse_conn *fc, unsigned int map_alignment) { if (fc->dax && (map_alignment > FUSE_DAX_SHIFT)) { pr_warn("FUSE: map_alignment %u incompatible with dax mem range size %u\n", map_alignment, FUSE_DAX_SZ); return false; } return true; } void fuse_dax_cancel_work(struct fuse_conn *fc) { struct fuse_conn_dax *fcd = fc->dax; if (fcd) cancel_delayed_work_sync(&fcd->free_work); } EXPORT_SYMBOL_GPL(fuse_dax_cancel_work);
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