diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/filemap.c | 145 | ||||
| -rw-r--r-- | mm/madvise.c | 2 | ||||
| -rw-r--r-- | mm/memory-failure.c | 2 | ||||
| -rw-r--r-- | mm/readahead.c | 2 | ||||
| -rw-r--r-- | mm/rmap.c | 41 | ||||
| -rw-r--r-- | mm/shmem.c | 20 | ||||
| -rw-r--r-- | mm/truncate.c | 9 |
7 files changed, 162 insertions, 59 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index d1458ecf2f51..0fad08331cf4 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -76,8 +76,9 @@ * ->swap_lock (exclusive_swap_page, others) * ->i_pages lock * - * ->i_mutex - * ->i_mmap_rwsem (truncate->unmap_mapping_range) + * ->i_rwsem + * ->invalidate_lock (acquired by fs in truncate path) + * ->i_mmap_rwsem (truncate->unmap_mapping_range) * * ->mmap_lock * ->i_mmap_rwsem @@ -85,9 +86,10 @@ * ->i_pages lock (arch-dependent flush_dcache_mmap_lock) * * ->mmap_lock - * ->lock_page (access_process_vm) + * ->invalidate_lock (filemap_fault) + * ->lock_page (filemap_fault, access_process_vm) * - * ->i_mutex (generic_perform_write) + * ->i_rwsem (generic_perform_write) * ->mmap_lock (fault_in_pages_readable->do_page_fault) * * bdi->wb.list_lock @@ -1008,6 +1010,44 @@ EXPORT_SYMBOL(__page_cache_alloc); #endif /* + * filemap_invalidate_lock_two - lock invalidate_lock for two mappings + * + * Lock exclusively invalidate_lock of any passed mapping that is not NULL. + * + * @mapping1: the first mapping to lock + * @mapping2: the second mapping to lock + */ +void filemap_invalidate_lock_two(struct address_space *mapping1, + struct address_space *mapping2) +{ + if (mapping1 > mapping2) + swap(mapping1, mapping2); + if (mapping1) + down_write(&mapping1->invalidate_lock); + if (mapping2 && mapping1 != mapping2) + down_write_nested(&mapping2->invalidate_lock, 1); +} +EXPORT_SYMBOL(filemap_invalidate_lock_two); + +/* + * filemap_invalidate_unlock_two - unlock invalidate_lock for two mappings + * + * Unlock exclusive invalidate_lock of any passed mapping that is not NULL. + * + * @mapping1: the first mapping to unlock + * @mapping2: the second mapping to unlock + */ +void filemap_invalidate_unlock_two(struct address_space *mapping1, + struct address_space *mapping2) +{ + if (mapping1) + up_write(&mapping1->invalidate_lock); + if (mapping2 && mapping1 != mapping2) + up_write(&mapping2->invalidate_lock); +} +EXPORT_SYMBOL(filemap_invalidate_unlock_two); + +/* * In order to wait for pages to become available there must be * waitqueues associated with pages. By using a hash table of * waitqueues where the bucket discipline is to maintain all @@ -2368,20 +2408,30 @@ static int filemap_update_page(struct kiocb *iocb, { int error; + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!filemap_invalidate_trylock_shared(mapping)) + return -EAGAIN; + } else { + filemap_invalidate_lock_shared(mapping); + } + if (!trylock_page(page)) { + error = -EAGAIN; if (iocb->ki_flags & (IOCB_NOWAIT | IOCB_NOIO)) - return -EAGAIN; + goto unlock_mapping; if (!(iocb->ki_flags & IOCB_WAITQ)) { + filemap_invalidate_unlock_shared(mapping); put_and_wait_on_page_locked(page, TASK_KILLABLE); return AOP_TRUNCATED_PAGE; } error = __lock_page_async(page, iocb->ki_waitq); if (error) - return error; + goto unlock_mapping; } + error = AOP_TRUNCATED_PAGE; if (!page->mapping) - goto truncated; + goto unlock; error = 0; if (filemap_range_uptodate(mapping, iocb->ki_pos, iter, page)) @@ -2392,15 +2442,13 @@ static int filemap_update_page(struct kiocb *iocb, goto unlock; error = filemap_read_page(iocb->ki_filp, mapping, page); - if (error == AOP_TRUNCATED_PAGE) - put_page(page); - return error; -truncated: - unlock_page(page); - put_page(page); - return AOP_TRUNCATED_PAGE; + goto unlock_mapping; unlock: unlock_page(page); +unlock_mapping: + filemap_invalidate_unlock_shared(mapping); + if (error == AOP_TRUNCATED_PAGE) + put_page(page); return error; } @@ -2415,6 +2463,19 @@ static int filemap_create_page(struct file *file, if (!page) return -ENOMEM; + /* + * Protect against truncate / hole punch. Grabbing invalidate_lock here + * assures we cannot instantiate and bring uptodate new pagecache pages + * after evicting page cache during truncate and before actually + * freeing blocks. Note that we could release invalidate_lock after + * inserting the page into page cache as the locked page would then be + * enough to synchronize with hole punching. But there are code paths + * such as filemap_update_page() filling in partially uptodate pages or + * ->readpages() that need to hold invalidate_lock while mapping blocks + * for IO so let's hold the lock here as well to keep locking rules + * simple. + */ + filemap_invalidate_lock_shared(mapping); error = add_to_page_cache_lru(page, mapping, index, mapping_gfp_constraint(mapping, GFP_KERNEL)); if (error == -EEXIST) @@ -2426,9 +2487,11 @@ static int filemap_create_page(struct file *file, if (error) goto error; + filemap_invalidate_unlock_shared(mapping); pagevec_add(pvec, page); return 0; error: + filemap_invalidate_unlock_shared(mapping); put_page(page); return error; } @@ -2967,6 +3030,7 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) pgoff_t max_off; struct page *page; vm_fault_t ret = 0; + bool mapping_locked = false; max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); if (unlikely(offset >= max_off)) @@ -2976,25 +3040,39 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) * Do we have something in the page cache already? */ page = find_get_page(mapping, offset); - if (likely(page) && !(vmf->flags & FAULT_FLAG_TRIED)) { + if (likely(page)) { /* - * We found the page, so try async readahead before - * waiting for the lock. + * We found the page, so try async readahead before waiting for + * the lock. */ - fpin = do_async_mmap_readahead(vmf, page); - } else if (!page) { + if (!(vmf->flags & FAULT_FLAG_TRIED)) + fpin = do_async_mmap_readahead(vmf, page); + if (unlikely(!PageUptodate(page))) { + filemap_invalidate_lock_shared(mapping); + mapping_locked = true; + } + } else { /* No page in the page cache at all */ count_vm_event(PGMAJFAULT); count_memcg_event_mm(vmf->vma->vm_mm, PGMAJFAULT); ret = VM_FAULT_MAJOR; fpin = do_sync_mmap_readahead(vmf); retry_find: + /* + * See comment in filemap_create_page() why we need + * invalidate_lock + */ + if (!mapping_locked) { + filemap_invalidate_lock_shared(mapping); + mapping_locked = true; + } page = pagecache_get_page(mapping, offset, FGP_CREAT|FGP_FOR_MMAP, vmf->gfp_mask); if (!page) { if (fpin) goto out_retry; + filemap_invalidate_unlock_shared(mapping); return VM_FAULT_OOM; } } @@ -3014,8 +3092,20 @@ retry_find: * We have a locked page in the page cache, now we need to check * that it's up-to-date. If not, it is going to be due to an error. */ - if (unlikely(!PageUptodate(page))) + if (unlikely(!PageUptodate(page))) { + /* + * The page was in cache and uptodate and now it is not. + * Strange but possible since we didn't hold the page lock all + * the time. Let's drop everything get the invalidate lock and + * try again. + */ + if (!mapping_locked) { + unlock_page(page); + put_page(page); + goto retry_find; + } goto page_not_uptodate; + } /* * We've made it this far and we had to drop our mmap_lock, now is the @@ -3026,6 +3116,8 @@ retry_find: unlock_page(page); goto out_retry; } + if (mapping_locked) + filemap_invalidate_unlock_shared(mapping); /* * Found the page and have a reference on it. @@ -3056,6 +3148,7 @@ page_not_uptodate: if (!error || error == AOP_TRUNCATED_PAGE) goto retry_find; + filemap_invalidate_unlock_shared(mapping); return VM_FAULT_SIGBUS; @@ -3067,6 +3160,8 @@ out_retry: */ if (page) put_page(page); + if (mapping_locked) + filemap_invalidate_unlock_shared(mapping); if (fpin) fput(fpin); return ret | VM_FAULT_RETRY; @@ -3437,6 +3532,8 @@ out: * * If the page does not get brought uptodate, return -EIO. * + * The function expects mapping->invalidate_lock to be already held. + * * Return: up to date page on success, ERR_PTR() on failure. */ struct page *read_cache_page(struct address_space *mapping, @@ -3460,6 +3557,8 @@ EXPORT_SYMBOL(read_cache_page); * * If the page does not get brought uptodate, return -EIO. * + * The function expects mapping->invalidate_lock to be already held. + * * Return: up to date page on success, ERR_PTR() on failure. */ struct page *read_cache_page_gfp(struct address_space *mapping, @@ -3704,12 +3803,12 @@ EXPORT_SYMBOL(generic_perform_write); * modification times and calls proper subroutines depending on whether we * do direct IO or a standard buffered write. * - * It expects i_mutex to be grabbed unless we work on a block device or similar + * It expects i_rwsem to be grabbed unless we work on a block device or similar * object which does not need locking at all. * * This function does *not* take care of syncing data in case of O_SYNC write. * A caller has to handle it. This is mainly due to the fact that we want to - * avoid syncing under i_mutex. + * avoid syncing under i_rwsem. * * Return: * * number of bytes written, even for truncated writes @@ -3797,7 +3896,7 @@ EXPORT_SYMBOL(__generic_file_write_iter); * * This is a wrapper around __generic_file_write_iter() to be used by most * filesystems. It takes care of syncing the file in case of O_SYNC file - * and acquires i_mutex as needed. + * and acquires i_rwsem as needed. * Return: * * negative error code if no data has been written at all of * vfs_fsync_range() failed for a synchronous write diff --git a/mm/madvise.c b/mm/madvise.c index 5c065bc8b5f6..56324a3dbc4e 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -912,7 +912,7 @@ static long madvise_remove(struct vm_area_struct *vma, + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); /* - * Filesystem's fallocate may need to take i_mutex. We need to + * Filesystem's fallocate may need to take i_rwsem. We need to * explicitly grab a reference because the vma (and hence the * vma's reference to the file) can go away as soon as we drop * mmap_lock. diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 470400cc7513..e1f87cf13235 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -866,7 +866,7 @@ static int me_pagecache_clean(struct page *p, unsigned long pfn) /* * Truncation is a bit tricky. Enable it per file system for now. * - * Open: to take i_mutex or not for this? Right now we don't. + * Open: to take i_rwsem or not for this? Right now we don't. */ ret = truncate_error_page(p, pfn, mapping); out: diff --git a/mm/readahead.c b/mm/readahead.c index d589f147f4c2..41b75d76d36e 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -192,6 +192,7 @@ void page_cache_ra_unbounded(struct readahead_control *ractl, */ unsigned int nofs = memalloc_nofs_save(); + filemap_invalidate_lock_shared(mapping); /* * Preallocate as many pages as we will need. */ @@ -236,6 +237,7 @@ void page_cache_ra_unbounded(struct readahead_control *ractl, * will then handle the error. */ read_pages(ractl, &page_pool, false); + filemap_invalidate_unlock_shared(mapping); memalloc_nofs_restore(nofs); } EXPORT_SYMBOL_GPL(page_cache_ra_unbounded); diff --git a/mm/rmap.c b/mm/rmap.c index b9eb5c12f3fe..2d29a57d29e8 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -20,28 +20,29 @@ /* * Lock ordering in mm: * - * inode->i_mutex (while writing or truncating, not reading or faulting) + * inode->i_rwsem (while writing or truncating, not reading or faulting) * mm->mmap_lock - * page->flags PG_locked (lock_page) * (see huegtlbfs below) - * hugetlbfs_i_mmap_rwsem_key (in huge_pmd_share) - * mapping->i_mmap_rwsem - * hugetlb_fault_mutex (hugetlbfs specific page fault mutex) - * anon_vma->rwsem - * mm->page_table_lock or pte_lock - * swap_lock (in swap_duplicate, swap_info_get) - * mmlist_lock (in mmput, drain_mmlist and others) - * mapping->private_lock (in __set_page_dirty_buffers) - * lock_page_memcg move_lock (in __set_page_dirty_buffers) - * i_pages lock (widely used) - * lruvec->lru_lock (in lock_page_lruvec_irq) - * inode->i_lock (in set_page_dirty's __mark_inode_dirty) - * bdi.wb->list_lock (in set_page_dirty's __mark_inode_dirty) - * sb_lock (within inode_lock in fs/fs-writeback.c) - * i_pages lock (widely used, in set_page_dirty, - * in arch-dependent flush_dcache_mmap_lock, - * within bdi.wb->list_lock in __sync_single_inode) + * mapping->invalidate_lock (in filemap_fault) + * page->flags PG_locked (lock_page) * (see hugetlbfs below) + * hugetlbfs_i_mmap_rwsem_key (in huge_pmd_share) + * mapping->i_mmap_rwsem + * hugetlb_fault_mutex (hugetlbfs specific page fault mutex) + * anon_vma->rwsem + * mm->page_table_lock or pte_lock + * swap_lock (in swap_duplicate, swap_info_get) + * mmlist_lock (in mmput, drain_mmlist and others) + * mapping->private_lock (in __set_page_dirty_buffers) + * lock_page_memcg move_lock (in __set_page_dirty_buffers) + * i_pages lock (widely used) + * lruvec->lru_lock (in lock_page_lruvec_irq) + * inode->i_lock (in set_page_dirty's __mark_inode_dirty) + * bdi.wb->list_lock (in set_page_dirty's __mark_inode_dirty) + * sb_lock (within inode_lock in fs/fs-writeback.c) + * i_pages lock (widely used, in set_page_dirty, + * in arch-dependent flush_dcache_mmap_lock, + * within bdi.wb->list_lock in __sync_single_inode) * - * anon_vma->rwsem,mapping->i_mutex (memory_failure, collect_procs_anon) + * anon_vma->rwsem,mapping->i_mmap_rwsem (memory_failure, collect_procs_anon) * ->tasklist_lock * pte map lock * diff --git a/mm/shmem.c b/mm/shmem.c index dacda7463d54..3107acee4f71 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -96,7 +96,7 @@ static struct vfsmount *shm_mnt; /* * shmem_fallocate communicates with shmem_fault or shmem_writepage via - * inode->i_private (with i_mutex making sure that it has only one user at + * inode->i_private (with i_rwsem making sure that it has only one user at * a time): we would prefer not to enlarge the shmem inode just for that. */ struct shmem_falloc { @@ -774,7 +774,7 @@ static int shmem_free_swap(struct address_space *mapping, * Determine (in bytes) how many of the shmem object's pages mapped by the * given offsets are swapped out. * - * This is safe to call without i_mutex or the i_pages lock thanks to RCU, + * This is safe to call without i_rwsem or the i_pages lock thanks to RCU, * as long as the inode doesn't go away and racy results are not a problem. */ unsigned long shmem_partial_swap_usage(struct address_space *mapping, @@ -806,7 +806,7 @@ unsigned long shmem_partial_swap_usage(struct address_space *mapping, * Determine (in bytes) how many of the shmem object's pages mapped by the * given vma is swapped out. * - * This is safe to call without i_mutex or the i_pages lock thanks to RCU, + * This is safe to call without i_rwsem or the i_pages lock thanks to RCU, * as long as the inode doesn't go away and racy results are not a problem. */ unsigned long shmem_swap_usage(struct vm_area_struct *vma) @@ -1069,7 +1069,7 @@ static int shmem_setattr(struct user_namespace *mnt_userns, loff_t oldsize = inode->i_size; loff_t newsize = attr->ia_size; - /* protected by i_mutex */ + /* protected by i_rwsem */ if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) || (newsize > oldsize && (info->seals & F_SEAL_GROW))) return -EPERM; @@ -2059,7 +2059,7 @@ static vm_fault_t shmem_fault(struct vm_fault *vmf) /* * Trinity finds that probing a hole which tmpfs is punching can * prevent the hole-punch from ever completing: which in turn - * locks writers out with its hold on i_mutex. So refrain from + * locks writers out with its hold on i_rwsem. So refrain from * faulting pages into the hole while it's being punched. Although * shmem_undo_range() does remove the additions, it may be unable to * keep up, as each new page needs its own unmap_mapping_range() call, @@ -2070,7 +2070,7 @@ static vm_fault_t shmem_fault(struct vm_fault *vmf) * we just need to make racing faults a rare case. * * The implementation below would be much simpler if we just used a - * standard mutex or completion: but we cannot take i_mutex in fault, + * standard mutex or completion: but we cannot take i_rwsem in fault, * and bloating every shmem inode for this unlikely case would be sad. */ if (unlikely(inode->i_private)) { @@ -2470,7 +2470,7 @@ shmem_write_begin(struct file *file, struct address_space *mapping, struct shmem_inode_info *info = SHMEM_I(inode); pgoff_t index = pos >> PAGE_SHIFT; - /* i_mutex is held by caller */ + /* i_rwsem is held by caller */ if (unlikely(info->seals & (F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_FUTURE_WRITE))) { if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) @@ -2570,7 +2570,7 @@ static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to) /* * We must evaluate after, since reads (unlike writes) - * are called without i_mutex protection against truncate + * are called without i_rwsem protection against truncate */ nr = PAGE_SIZE; i_size = i_size_read(inode); @@ -2640,7 +2640,7 @@ static loff_t shmem_file_llseek(struct file *file, loff_t offset, int whence) return -ENXIO; inode_lock(inode); - /* We're holding i_mutex so we can access i_size directly */ + /* We're holding i_rwsem so we can access i_size directly */ offset = mapping_seek_hole_data(mapping, offset, inode->i_size, whence); if (offset >= 0) offset = vfs_setpos(file, offset, MAX_LFS_FILESIZE); @@ -2669,7 +2669,7 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset, loff_t unmap_end = round_down(offset + len, PAGE_SIZE) - 1; DECLARE_WAIT_QUEUE_HEAD_ONSTACK(shmem_falloc_waitq); - /* protected by i_mutex */ + /* protected by i_rwsem */ if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) { error = -EPERM; goto out; diff --git a/mm/truncate.c b/mm/truncate.c index 234ddd879caa..44ad5e515140 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -412,7 +412,8 @@ EXPORT_SYMBOL(truncate_inode_pages_range); * @mapping: mapping to truncate * @lstart: offset from which to truncate * - * Called under (and serialised by) inode->i_mutex. + * Called under (and serialised by) inode->i_rwsem and + * mapping->invalidate_lock. * * Note: When this function returns, there can be a page in the process of * deletion (inside __delete_from_page_cache()) in the specified range. Thus @@ -429,7 +430,7 @@ EXPORT_SYMBOL(truncate_inode_pages); * truncate_inode_pages_final - truncate *all* pages before inode dies * @mapping: mapping to truncate * - * Called under (and serialized by) inode->i_mutex. + * Called under (and serialized by) inode->i_rwsem. * * Filesystems have to use this in the .evict_inode path to inform the * VM that this is the final truncate and the inode is going away. @@ -748,7 +749,7 @@ EXPORT_SYMBOL(truncate_pagecache); * setattr function when ATTR_SIZE is passed in. * * Must be called with a lock serializing truncates and writes (generally - * i_mutex but e.g. xfs uses a different lock) and before all filesystem + * i_rwsem but e.g. xfs uses a different lock) and before all filesystem * specific block truncation has been performed. */ void truncate_setsize(struct inode *inode, loff_t newsize) @@ -777,7 +778,7 @@ EXPORT_SYMBOL(truncate_setsize); * * The function must be called after i_size is updated so that page fault * coming after we unlock the page will already see the new i_size. - * The function must be called while we still hold i_mutex - this not only + * The function must be called while we still hold i_rwsem - this not only * makes sure i_size is stable but also that userspace cannot observe new * i_size value before we are prepared to store mmap writes at new inode size. */ |