From 7f59b277f79e8aacaa2ec7e549be6c27985c27f2 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 4 Jan 2021 22:33:02 -0800 Subject: f2fs: clean up post-read processing Rework the post-read processing logic to be much easier to understand. At least one bug is fixed by this: if an I/O error occurred when reading from disk, decryption and verity would be performed on the uninitialized data, causing misleading messages in the kernel log. Signed-off-by: Eric Biggers Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/compress.c | 149 ++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 108 insertions(+), 41 deletions(-) (limited to 'fs/f2fs/compress.c') diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index a345a41e2119..1696f9183ff5 100644 --- a/fs/f2fs/compress.c +++ b/fs/f2fs/compress.c @@ -756,38 +756,27 @@ out: return ret; } -void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity) +static void f2fs_decompress_cluster(struct decompress_io_ctx *dic) { - struct decompress_io_ctx *dic = - (struct decompress_io_ctx *)page_private(page); struct f2fs_sb_info *sbi = F2FS_I_SB(dic->inode); - struct f2fs_inode_info *fi= F2FS_I(dic->inode); + struct f2fs_inode_info *fi = F2FS_I(dic->inode); const struct f2fs_compress_ops *cops = f2fs_cops[fi->i_compress_algorithm]; int ret; int i; - dec_page_count(sbi, F2FS_RD_DATA); - - if (bio->bi_status || PageError(page)) - dic->failed = true; - - if (atomic_dec_return(&dic->pending_pages)) - return; - trace_f2fs_decompress_pages_start(dic->inode, dic->cluster_idx, dic->cluster_size, fi->i_compress_algorithm); - /* submit partial compressed pages */ if (dic->failed) { ret = -EIO; - goto out_free_dic; + goto out_end_io; } dic->tpages = page_array_alloc(dic->inode, dic->cluster_size); if (!dic->tpages) { ret = -ENOMEM; - goto out_free_dic; + goto out_end_io; } for (i = 0; i < dic->cluster_size; i++) { @@ -799,20 +788,20 @@ void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity) dic->tpages[i] = f2fs_compress_alloc_page(); if (!dic->tpages[i]) { ret = -ENOMEM; - goto out_free_dic; + goto out_end_io; } } if (cops->init_decompress_ctx) { ret = cops->init_decompress_ctx(dic); if (ret) - goto out_free_dic; + goto out_end_io; } dic->rbuf = f2fs_vmap(dic->tpages, dic->cluster_size); if (!dic->rbuf) { ret = -ENOMEM; - goto destroy_decompress_ctx; + goto out_destroy_decompress_ctx; } dic->cbuf = f2fs_vmap(dic->cpages, dic->nr_cpages); @@ -851,18 +840,34 @@ out_vunmap_cbuf: vm_unmap_ram(dic->cbuf, dic->nr_cpages); out_vunmap_rbuf: vm_unmap_ram(dic->rbuf, dic->cluster_size); -destroy_decompress_ctx: +out_destroy_decompress_ctx: if (cops->destroy_decompress_ctx) cops->destroy_decompress_ctx(dic); -out_free_dic: - if (!verity) - f2fs_decompress_end_io(dic->rpages, dic->cluster_size, - ret, false); - +out_end_io: trace_f2fs_decompress_pages_end(dic->inode, dic->cluster_idx, dic->clen, ret); - if (!verity) - f2fs_free_dic(dic); + f2fs_decompress_end_io(dic, ret); +} + +/* + * This is called when a page of a compressed cluster has been read from disk + * (or failed to be read from disk). It checks whether this page was the last + * page being waited on in the cluster, and if so, it decompresses the cluster + * (or in the case of a failure, cleans up without actually decompressing). + */ +void f2fs_end_read_compressed_page(struct page *page, bool failed) +{ + struct decompress_io_ctx *dic = + (struct decompress_io_ctx *)page_private(page); + struct f2fs_sb_info *sbi = F2FS_I_SB(dic->inode); + + dec_page_count(sbi, F2FS_RD_DATA); + + if (failed) + WRITE_ONCE(dic->failed, true); + + if (atomic_dec_and_test(&dic->remaining_pages)) + f2fs_decompress_cluster(dic); } static bool is_page_in_cluster(struct compress_ctx *cc, pgoff_t index) @@ -1529,6 +1534,8 @@ destroy_out: return err; } +static void f2fs_free_dic(struct decompress_io_ctx *dic); + struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc) { struct decompress_io_ctx *dic; @@ -1547,12 +1554,14 @@ struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc) dic->magic = F2FS_COMPRESSED_PAGE_MAGIC; dic->inode = cc->inode; - atomic_set(&dic->pending_pages, cc->nr_cpages); + atomic_set(&dic->remaining_pages, cc->nr_cpages); dic->cluster_idx = cc->cluster_idx; dic->cluster_size = cc->cluster_size; dic->log_cluster_size = cc->log_cluster_size; dic->nr_cpages = cc->nr_cpages; + refcount_set(&dic->refcnt, 1); dic->failed = false; + dic->need_verity = f2fs_need_verity(cc->inode, start_idx); for (i = 0; i < dic->cluster_size; i++) dic->rpages[i] = cc->rpages[i]; @@ -1581,7 +1590,7 @@ out_free: return ERR_PTR(-ENOMEM); } -void f2fs_free_dic(struct decompress_io_ctx *dic) +static void f2fs_free_dic(struct decompress_io_ctx *dic) { int i; @@ -1609,30 +1618,88 @@ void f2fs_free_dic(struct decompress_io_ctx *dic) kmem_cache_free(dic_entry_slab, dic); } -void f2fs_decompress_end_io(struct page **rpages, - unsigned int cluster_size, bool err, bool verity) +static void f2fs_put_dic(struct decompress_io_ctx *dic) +{ + if (refcount_dec_and_test(&dic->refcnt)) + f2fs_free_dic(dic); +} + +/* + * Update and unlock the cluster's pagecache pages, and release the reference to + * the decompress_io_ctx that was being held for I/O completion. + */ +static void __f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed) { int i; - for (i = 0; i < cluster_size; i++) { - struct page *rpage = rpages[i]; + for (i = 0; i < dic->cluster_size; i++) { + struct page *rpage = dic->rpages[i]; if (!rpage) continue; - if (err || PageError(rpage)) - goto clear_uptodate; - - if (!verity || fsverity_verify_page(rpage)) { + /* PG_error was set if verity failed. */ + if (failed || PageError(rpage)) { + ClearPageUptodate(rpage); + /* will re-read again later */ + ClearPageError(rpage); + } else { SetPageUptodate(rpage); - goto unlock; } -clear_uptodate: - ClearPageUptodate(rpage); - ClearPageError(rpage); -unlock: unlock_page(rpage); } + + f2fs_put_dic(dic); +} + +static void f2fs_verify_cluster(struct work_struct *work) +{ + struct decompress_io_ctx *dic = + container_of(work, struct decompress_io_ctx, verity_work); + int i; + + /* Verify the cluster's decompressed pages with fs-verity. */ + for (i = 0; i < dic->cluster_size; i++) { + struct page *rpage = dic->rpages[i]; + + if (rpage && !fsverity_verify_page(rpage)) + SetPageError(rpage); + } + + __f2fs_decompress_end_io(dic, false); +} + +/* + * This is called when a compressed cluster has been decompressed + * (or failed to be read and/or decompressed). + */ +void f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed) +{ + if (!failed && dic->need_verity) { + /* + * Note that to avoid deadlocks, the verity work can't be done + * on the decompression workqueue. This is because verifying + * the data pages can involve reading metadata pages from the + * file, and these metadata pages may be compressed. + */ + INIT_WORK(&dic->verity_work, f2fs_verify_cluster); + fsverity_enqueue_verify_work(&dic->verity_work); + } else { + __f2fs_decompress_end_io(dic, failed); + } +} + +/* + * Put a reference to a compressed page's decompress_io_ctx. + * + * This is called when the page is no longer needed and can be freed. + */ +void f2fs_put_page_dic(struct page *page) +{ + struct decompress_io_ctx *dic = + (struct decompress_io_ctx *)page_private(page); + + f2fs_put_dic(dic); } int f2fs_init_page_array_cache(struct f2fs_sb_info *sbi) -- cgit v1.2.3