From e99b0ea39354cf308423588df5daf69c42dbd735 Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Tue, 25 Oct 2016 10:51:55 +0800 Subject: [PATCH] ceph: try getting buffer capability for readahead/fadvise commit 2b1ac852eb67a6e95595e576371d23519105559f upstream. For readahead/fadvise cases, caller of ceph_readpages does not hold buffer capability. Pages can be added to page cache while there is no buffer capability. This can cause data integrity issue. Signed-off-by: Yan, Zheng Signed-off-by: Greg Kroah-Hartman --- fs/ceph/addr.c | 58 ++++++++++++++++++++++++++++++++++++++++--------- fs/ceph/caps.c | 21 ++++++++++++++++++ fs/ceph/file.c | 3 ++- fs/ceph/super.h | 2 ++ 4 files changed, 73 insertions(+), 11 deletions(-) diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c index 1e643c718917..18dc18f8af2c 100644 --- a/fs/ceph/addr.c +++ b/fs/ceph/addr.c @@ -315,7 +315,32 @@ static int start_read(struct inode *inode, struct list_head *page_list, int max) struct page **pages; pgoff_t next_index; int nr_pages = 0; - int ret; + int got = 0; + int ret = 0; + + if (!current->journal_info) { + /* caller of readpages does not hold buffer and read caps + * (fadvise, madvise and readahead cases) */ + int want = CEPH_CAP_FILE_CACHE; + ret = ceph_try_get_caps(ci, CEPH_CAP_FILE_RD, want, &got); + if (ret < 0) { + dout("start_read %p, error getting cap\n", inode); + } else if (!(got & want)) { + dout("start_read %p, no cache cap\n", inode); + ret = 0; + } + if (ret <= 0) { + if (got) + ceph_put_cap_refs(ci, got); + while (!list_empty(page_list)) { + page = list_entry(page_list->prev, + struct page, lru); + list_del(&page->lru); + put_page(page); + } + return ret; + } + } off = (u64) page_offset(page); @@ -338,15 +363,18 @@ static int start_read(struct inode *inode, struct list_head *page_list, int max) CEPH_OSD_FLAG_READ, NULL, ci->i_truncate_seq, ci->i_truncate_size, false); - if (IS_ERR(req)) - return PTR_ERR(req); + if (IS_ERR(req)) { + ret = PTR_ERR(req); + goto out; + } /* build page vector */ nr_pages = calc_pages_for(0, len); pages = kmalloc(sizeof(*pages) * nr_pages, GFP_KERNEL); - ret = -ENOMEM; - if (!pages) - goto out; + if (!pages) { + ret = -ENOMEM; + goto out_put; + } for (i = 0; i < nr_pages; ++i) { page = list_entry(page_list->prev, struct page, lru); BUG_ON(PageLocked(page)); @@ -379,6 +407,12 @@ static int start_read(struct inode *inode, struct list_head *page_list, int max) if (ret < 0) goto out_pages; ceph_osdc_put_request(req); + + /* After adding locked pages to page cache, the inode holds cache cap. + * So we can drop our cap refs. */ + if (got) + ceph_put_cap_refs(ci, got); + return nr_pages; out_pages: @@ -387,8 +421,11 @@ out_pages: unlock_page(pages[i]); } ceph_put_page_vector(pages, nr_pages, false); -out: +out_put: ceph_osdc_put_request(req); +out: + if (got) + ceph_put_cap_refs(ci, got); return ret; } @@ -425,7 +462,6 @@ static int ceph_readpages(struct file *file, struct address_space *mapping, rc = start_read(inode, page_list, max); if (rc < 0) goto out; - BUG_ON(rc == 0); } out: ceph_fscache_readpages_cancel(inode, page_list); @@ -1372,9 +1408,11 @@ static int ceph_filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) inode, off, (size_t)PAGE_SIZE, ceph_cap_string(got)); if ((got & (CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO)) || - ci->i_inline_version == CEPH_INLINE_NONE) + ci->i_inline_version == CEPH_INLINE_NONE) { + current->journal_info = vma->vm_file; ret = filemap_fault(vma, vmf); - else + current->journal_info = NULL; + } else ret = -EAGAIN; dout("filemap_fault %p %llu~%zd dropping cap refs on %s ret %d\n", diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index f3f21105b860..03951f90ecf7 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -2479,6 +2479,27 @@ static void check_max_size(struct inode *inode, loff_t endoff) ceph_check_caps(ci, CHECK_CAPS_AUTHONLY, NULL); } +int ceph_try_get_caps(struct ceph_inode_info *ci, int need, int want, int *got) +{ + int ret, err = 0; + + BUG_ON(need & ~CEPH_CAP_FILE_RD); + BUG_ON(want & ~(CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)); + ret = ceph_pool_perm_check(ci, need); + if (ret < 0) + return ret; + + ret = try_get_cap_refs(ci, need, want, 0, true, got, &err); + if (ret) { + if (err == -EAGAIN) { + ret = 0; + } else if (err < 0) { + ret = err; + } + } + return ret; +} + /* * Wait for caps, and take cap references. If we can't get a WR cap * due to a small max_size, make sure we check_max_size (and possibly diff --git a/fs/ceph/file.c b/fs/ceph/file.c index f995e3528a33..ca3f630db90f 100644 --- a/fs/ceph/file.c +++ b/fs/ceph/file.c @@ -1249,8 +1249,9 @@ again: dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n", inode, ceph_vinop(inode), iocb->ki_pos, (unsigned)len, ceph_cap_string(got)); - + current->journal_info = filp; ret = generic_file_read_iter(iocb, to); + current->journal_info = NULL; } dout("aio_read %p %llx.%llx dropping cap refs on %s = %d\n", inode, ceph_vinop(inode), ceph_cap_string(got), (int)ret); diff --git a/fs/ceph/super.h b/fs/ceph/super.h index 3e3fa9163059..622d5dd9f616 100644 --- a/fs/ceph/super.h +++ b/fs/ceph/super.h @@ -905,6 +905,8 @@ extern int ceph_encode_dentry_release(void **p, struct dentry *dn, extern int ceph_get_caps(struct ceph_inode_info *ci, int need, int want, loff_t endoff, int *got, struct page **pinned_page); +extern int ceph_try_get_caps(struct ceph_inode_info *ci, + int need, int want, int *got); /* for counting open files by mode */ extern void __ceph_get_fmode(struct ceph_inode_info *ci, int mode);