From 8958a02daa3b4d376b41add399449df1371f2319 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 13 Nov 2021 12:03:03 -0800 Subject: [PATCH] Revert "mm: shmem: don't truncate page if memory failure happens" This reverts commit 4f3ccb3c0da7c8e03522ae9b8b960ff6661364ef. The error handling of that patch was fundamentally broken, and it needs to be entirely re-done. For example, in shmem_write_begin() it would call shmem_getpage(), then ignore the error return from that, and look at the page pointer contents instead. And in shmem_read_mapping_page_gfp(), the patch tested PageHWPoison() on a page pointer that two lines earlier had potentially been set as an error pointer. These issues could be individually fixed, but when it has this many issues, I'm just reverting it instead of waiting for fixes. Link: https://lore.kernel.org/linux-mm/20211111084617.6746-1-ajaygargnsit@gmail.com/ Reported-by: Ajay Garg Reported-by: Jens Axboe Cc: Yang Shi Cc: Arnd Bergmann Cc: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory-failure.c | 14 +++----------- mm/shmem.c | 38 +++----------------------------------- mm/userfaultfd.c | 5 ----- 3 files changed, 6 insertions(+), 51 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index f64ebb6226cbf..07c875fdeaf0c 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -58,7 +58,6 @@ #include #include #include -#include #include "internal.h" #include "ras/ras_event.h" @@ -868,7 +867,6 @@ static int me_pagecache_clean(struct page_state *ps, struct page *p) { int ret; struct address_space *mapping; - bool extra_pins; delete_from_lru_cache(p); @@ -897,24 +895,18 @@ static int me_pagecache_clean(struct page_state *ps, struct page *p) goto out; } - /* - * The shmem page is kept in page cache instead of truncating - * so is expected to have an extra refcount after error-handling. - */ - extra_pins = shmem_mapping(mapping); - /* * Truncation is a bit tricky. Enable it per file system for now. * * Open: to take i_rwsem or not for this? Right now we don't. */ ret = truncate_error_page(p, page_to_pfn(p), mapping); - if (has_extra_refcount(ps, p, extra_pins)) - ret = MF_FAILED; - out: unlock_page(p); + if (has_extra_refcount(ps, p, false)) + ret = MF_FAILED; + return ret; } diff --git a/mm/shmem.c b/mm/shmem.c index f0eee4e221a76..dc038ce78700c 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2456,7 +2456,6 @@ shmem_write_begin(struct file *file, struct address_space *mapping, struct inode *inode = mapping->host; struct shmem_inode_info *info = SHMEM_I(inode); pgoff_t index = pos >> PAGE_SHIFT; - int ret = 0; /* i_rwsem is held by caller */ if (unlikely(info->seals & (F_SEAL_GROW | @@ -2467,15 +2466,7 @@ shmem_write_begin(struct file *file, struct address_space *mapping, return -EPERM; } - ret = shmem_getpage(inode, index, pagep, SGP_WRITE); - - if (*pagep && PageHWPoison(*pagep)) { - unlock_page(*pagep); - put_page(*pagep); - ret = -EIO; - } - - return ret; + return shmem_getpage(inode, index, pagep, SGP_WRITE); } static int @@ -2562,12 +2553,6 @@ static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to) if (sgp == SGP_CACHE) set_page_dirty(page); unlock_page(page); - - if (PageHWPoison(page)) { - put_page(page); - error = -EIO; - break; - } } /* @@ -3107,8 +3092,7 @@ static const char *shmem_get_link(struct dentry *dentry, page = find_get_page(inode->i_mapping, 0); if (!page) return ERR_PTR(-ECHILD); - if (PageHWPoison(page) || - !PageUptodate(page)) { + if (!PageUptodate(page)) { put_page(page); return ERR_PTR(-ECHILD); } @@ -3116,11 +3100,6 @@ static const char *shmem_get_link(struct dentry *dentry, error = shmem_getpage(inode, 0, &page, SGP_READ); if (error) return ERR_PTR(error); - if (page && PageHWPoison(page)) { - unlock_page(page); - put_page(page); - return ERR_PTR(-ECHILD); - } unlock_page(page); } set_delayed_call(done, shmem_put_link, page); @@ -3771,13 +3750,6 @@ static void shmem_destroy_inodecache(void) kmem_cache_destroy(shmem_inode_cachep); } -/* Keep the page in page cache instead of truncating it */ -static int shmem_error_remove_page(struct address_space *mapping, - struct page *page) -{ - return 0; -} - const struct address_space_operations shmem_aops = { .writepage = shmem_writepage, .set_page_dirty = __set_page_dirty_no_writeback, @@ -3788,7 +3760,7 @@ const struct address_space_operations shmem_aops = { #ifdef CONFIG_MIGRATION .migratepage = migrate_page, #endif - .error_remove_page = shmem_error_remove_page, + .error_remove_page = generic_error_remove_page, }; EXPORT_SYMBOL(shmem_aops); @@ -4199,10 +4171,6 @@ struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, page = ERR_PTR(error); else unlock_page(page); - - if (PageHWPoison(page)) - page = ERR_PTR(-EIO); - return page; #else /* diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 0780c2a57ff11..ac6f036298cd6 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -232,11 +232,6 @@ static int mcontinue_atomic_pte(struct mm_struct *dst_mm, goto out; } - if (PageHWPoison(page)) { - ret = -EIO; - goto out_release; - } - ret = mfill_atomic_install_pte(dst_mm, dst_pmd, dst_vma, dst_addr, page, false, wp_copy); if (ret) -- 2.39.5