From: Theodore Ts'o <tytso@xxxxxxx> commit c9af28fdd44922a6c10c9f8315718408af98e315 upstream. [Please apply to 4.4-stable. This fixes a bug which has caused problems on both Android and Chrome OS, and this fix has already been included in a number of ext4 encryption backports.] We don't want the writeback triggered from the journal commit (in data=writeback mode) to cause the journal to abort due to generic_writepages() returning an ENOMEM error. In addition, if fsync() fails with ENOMEM, most applications will probably not do the right thing. So if we are doing a data integrity sync, and ext4_encrypt() returns ENOMEM, we will submit any queued I/O to date, and then retry the allocation using GFP_NOFAIL. Google-Bug-Id: 27641567 Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx> --- fs/ext4/crypto.c | 37 +++++++++++++++++++++---------------- fs/ext4/ext4.h | 6 ++++-- fs/ext4/page-io.c | 14 +++++++++++++- fs/ext4/readpage.c | 2 +- 4 files changed, 39 insertions(+), 20 deletions(-) diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c index 9d6c2dcf1bd0..f240cef8b326 100644 --- a/fs/ext4/crypto.c +++ b/fs/ext4/crypto.c @@ -94,7 +94,8 @@ void ext4_release_crypto_ctx(struct ext4_crypto_ctx *ctx) * Return: An allocated and initialized encryption context on success; error * value or NULL otherwise. */ -struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode) +struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode, + gfp_t gfp_flags) { struct ext4_crypto_ctx *ctx = NULL; int res = 0; @@ -121,7 +122,7 @@ struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode) list_del(&ctx->free_list); spin_unlock_irqrestore(&ext4_crypto_ctx_lock, flags); if (!ctx) { - ctx = kmem_cache_zalloc(ext4_crypto_ctx_cachep, GFP_NOFS); + ctx = kmem_cache_zalloc(ext4_crypto_ctx_cachep, gfp_flags); if (!ctx) { res = -ENOMEM; goto out; @@ -258,7 +259,8 @@ static int ext4_page_crypto(struct inode *inode, ext4_direction_t rw, pgoff_t index, struct page *src_page, - struct page *dest_page) + struct page *dest_page, + gfp_t gfp_flags) { u8 xts_tweak[EXT4_XTS_TWEAK_SIZE]; @@ -269,7 +271,7 @@ static int ext4_page_crypto(struct inode *inode, struct crypto_ablkcipher *tfm = ci->ci_ctfm; int res = 0; - req = ablkcipher_request_alloc(tfm, GFP_NOFS); + req = ablkcipher_request_alloc(tfm, gfp_flags); if (!req) { printk_ratelimited(KERN_ERR "%s: crypto_request_alloc() failed\n", @@ -310,9 +312,10 @@ static int ext4_page_crypto(struct inode *inode, return 0; } -static struct page *alloc_bounce_page(struct ext4_crypto_ctx *ctx) +static struct page *alloc_bounce_page(struct ext4_crypto_ctx *ctx, + gfp_t gfp_flags) { - ctx->w.bounce_page = mempool_alloc(ext4_bounce_page_pool, GFP_NOWAIT); + ctx->w.bounce_page = mempool_alloc(ext4_bounce_page_pool, gfp_flags); if (ctx->w.bounce_page == NULL) return ERR_PTR(-ENOMEM); ctx->flags |= EXT4_WRITE_PATH_FL; @@ -335,7 +338,8 @@ static struct page *alloc_bounce_page(struct ext4_crypto_ctx *ctx) * error value or NULL. */ struct page *ext4_encrypt(struct inode *inode, - struct page *plaintext_page) + struct page *plaintext_page, + gfp_t gfp_flags) { struct ext4_crypto_ctx *ctx; struct page *ciphertext_page = NULL; @@ -343,17 +347,17 @@ struct page *ext4_encrypt(struct inode *inode, BUG_ON(!PageLocked(plaintext_page)); - ctx = ext4_get_crypto_ctx(inode); + ctx = ext4_get_crypto_ctx(inode, gfp_flags); if (IS_ERR(ctx)) return (struct page *) ctx; /* The encryption operation will require a bounce page. */ - ciphertext_page = alloc_bounce_page(ctx); + ciphertext_page = alloc_bounce_page(ctx, gfp_flags); if (IS_ERR(ciphertext_page)) goto errout; ctx->w.control_page = plaintext_page; err = ext4_page_crypto(inode, EXT4_ENCRYPT, plaintext_page->index, - plaintext_page, ciphertext_page); + plaintext_page, ciphertext_page, gfp_flags); if (err) { ciphertext_page = ERR_PTR(err); errout: @@ -381,8 +385,8 @@ int ext4_decrypt(struct page *page) { BUG_ON(!PageLocked(page)); - return ext4_page_crypto(page->mapping->host, - EXT4_DECRYPT, page->index, page, page); + return ext4_page_crypto(page->mapping->host, EXT4_DECRYPT, + page->index, page, page, GFP_NOFS); } int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex) @@ -403,11 +407,11 @@ int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex) BUG_ON(inode->i_sb->s_blocksize != PAGE_CACHE_SIZE); - ctx = ext4_get_crypto_ctx(inode); + ctx = ext4_get_crypto_ctx(inode, GFP_NOFS); if (IS_ERR(ctx)) return PTR_ERR(ctx); - ciphertext_page = alloc_bounce_page(ctx); + ciphertext_page = alloc_bounce_page(ctx, GFP_NOWAIT); if (IS_ERR(ciphertext_page)) { err = PTR_ERR(ciphertext_page); goto errout; @@ -415,11 +419,12 @@ int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex) while (len--) { err = ext4_page_crypto(inode, EXT4_ENCRYPT, lblk, - ZERO_PAGE(0), ciphertext_page); + ZERO_PAGE(0), ciphertext_page, + GFP_NOFS); if (err) goto errout; - bio = bio_alloc(GFP_KERNEL, 1); + bio = bio_alloc(GFP_NOWAIT, 1); if (!bio) { err = -ENOMEM; goto errout; diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 3de9bb357b4f..c8ad14c697c4 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2261,11 +2261,13 @@ extern struct kmem_cache *ext4_crypt_info_cachep; bool ext4_valid_contents_enc_mode(uint32_t mode); uint32_t ext4_validate_encryption_key_size(uint32_t mode, uint32_t size); extern struct workqueue_struct *ext4_read_workqueue; -struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode); +struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode, + gfp_t gfp_flags); void ext4_release_crypto_ctx(struct ext4_crypto_ctx *ctx); void ext4_restore_control_page(struct page *data_page); struct page *ext4_encrypt(struct inode *inode, - struct page *plaintext_page); + struct page *plaintext_page, + gfp_t gfp_flags); int ext4_decrypt(struct page *page); int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex); extern const struct dentry_operations ext4_encrypted_d_ops; diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c index 17fbe3882b8e..5c72ae5d62a6 100644 --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -23,6 +23,7 @@ #include <linux/kernel.h> #include <linux/slab.h> #include <linux/mm.h> +#include <linux/backing-dev.h> #include "ext4_jbd2.h" #include "xattr.h" @@ -485,9 +486,20 @@ int ext4_bio_write_page(struct ext4_io_submit *io, if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode) && nr_to_submit) { - data_page = ext4_encrypt(inode, page); + gfp_t gfp_flags = GFP_NOFS; + + retry_encrypt: + data_page = ext4_encrypt(inode, page, gfp_flags); if (IS_ERR(data_page)) { ret = PTR_ERR(data_page); + if (ret == ENOMEM && wbc->sync_mode == WB_SYNC_ALL) { + if (io->io_bio) { + ext4_io_submit(io); + congestion_wait(BLK_RW_ASYNC, HZ/50); + } + gfp_flags |= __GFP_NOFAIL; + goto retry_encrypt; + } data_page = NULL; goto out; } diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c index 5dc5e95063de..bc7642f57dc8 100644 --- a/fs/ext4/readpage.c +++ b/fs/ext4/readpage.c @@ -279,7 +279,7 @@ int ext4_mpage_readpages(struct address_space *mapping, if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode)) { - ctx = ext4_get_crypto_ctx(inode); + ctx = ext4_get_crypto_ctx(inode, GFP_NOFS); if (IS_ERR(ctx)) goto set_error_page; } -- 2.13.0.303.g4ebf302169-goog