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ext4 crypto: don't let data integrity writebacks fail with ENOMEM
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@mit.edu>
This commit is contained in:
Theodore Ts'o
parent
9e92f48c34
commit
c9af28fdd4
@ -91,7 +91,8 @@ void ext4_release_crypto_ctx(struct ext4_crypto_ctx *ctx)
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* Return: An allocated and initialized encryption context on success; error
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* value or NULL otherwise.
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*/
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struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode)
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struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode,
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gfp_t gfp_flags)
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{
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struct ext4_crypto_ctx *ctx = NULL;
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int res = 0;
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@ -118,7 +119,7 @@ struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode)
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list_del(&ctx->free_list);
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spin_unlock_irqrestore(&ext4_crypto_ctx_lock, flags);
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if (!ctx) {
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ctx = kmem_cache_zalloc(ext4_crypto_ctx_cachep, GFP_NOFS);
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ctx = kmem_cache_zalloc(ext4_crypto_ctx_cachep, gfp_flags);
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if (!ctx) {
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res = -ENOMEM;
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goto out;
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@ -255,7 +256,8 @@ static int ext4_page_crypto(struct inode *inode,
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ext4_direction_t rw,
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pgoff_t index,
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struct page *src_page,
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struct page *dest_page)
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struct page *dest_page,
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gfp_t gfp_flags)
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{
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u8 xts_tweak[EXT4_XTS_TWEAK_SIZE];
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@ -266,7 +268,7 @@ static int ext4_page_crypto(struct inode *inode,
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struct crypto_skcipher *tfm = ci->ci_ctfm;
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int res = 0;
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req = skcipher_request_alloc(tfm, GFP_NOFS);
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req = skcipher_request_alloc(tfm, gfp_flags);
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if (!req) {
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printk_ratelimited(KERN_ERR
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"%s: crypto_request_alloc() failed\n",
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@ -307,9 +309,10 @@ static int ext4_page_crypto(struct inode *inode,
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return 0;
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}
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static struct page *alloc_bounce_page(struct ext4_crypto_ctx *ctx)
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static struct page *alloc_bounce_page(struct ext4_crypto_ctx *ctx,
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gfp_t gfp_flags)
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{
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ctx->w.bounce_page = mempool_alloc(ext4_bounce_page_pool, GFP_NOWAIT);
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ctx->w.bounce_page = mempool_alloc(ext4_bounce_page_pool, gfp_flags);
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if (ctx->w.bounce_page == NULL)
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return ERR_PTR(-ENOMEM);
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ctx->flags |= EXT4_WRITE_PATH_FL;
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@ -332,7 +335,8 @@ static struct page *alloc_bounce_page(struct ext4_crypto_ctx *ctx)
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* error value or NULL.
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*/
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struct page *ext4_encrypt(struct inode *inode,
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struct page *plaintext_page)
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struct page *plaintext_page,
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gfp_t gfp_flags)
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{
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struct ext4_crypto_ctx *ctx;
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struct page *ciphertext_page = NULL;
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@ -340,17 +344,17 @@ struct page *ext4_encrypt(struct inode *inode,
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BUG_ON(!PageLocked(plaintext_page));
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ctx = ext4_get_crypto_ctx(inode);
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ctx = ext4_get_crypto_ctx(inode, gfp_flags);
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if (IS_ERR(ctx))
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return (struct page *) ctx;
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/* The encryption operation will require a bounce page. */
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ciphertext_page = alloc_bounce_page(ctx);
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ciphertext_page = alloc_bounce_page(ctx, gfp_flags);
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if (IS_ERR(ciphertext_page))
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goto errout;
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ctx->w.control_page = plaintext_page;
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err = ext4_page_crypto(inode, EXT4_ENCRYPT, plaintext_page->index,
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plaintext_page, ciphertext_page);
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plaintext_page, ciphertext_page, gfp_flags);
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if (err) {
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ciphertext_page = ERR_PTR(err);
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errout:
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@ -378,8 +382,8 @@ int ext4_decrypt(struct page *page)
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{
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BUG_ON(!PageLocked(page));
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return ext4_page_crypto(page->mapping->host,
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EXT4_DECRYPT, page->index, page, page);
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return ext4_page_crypto(page->mapping->host, EXT4_DECRYPT,
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page->index, page, page, GFP_NOFS);
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}
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int ext4_encrypted_zeroout(struct inode *inode, ext4_lblk_t lblk,
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@ -398,11 +402,11 @@ int ext4_encrypted_zeroout(struct inode *inode, ext4_lblk_t lblk,
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BUG_ON(inode->i_sb->s_blocksize != PAGE_CACHE_SIZE);
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ctx = ext4_get_crypto_ctx(inode);
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ctx = ext4_get_crypto_ctx(inode, GFP_NOFS);
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if (IS_ERR(ctx))
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return PTR_ERR(ctx);
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ciphertext_page = alloc_bounce_page(ctx);
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ciphertext_page = alloc_bounce_page(ctx, GFP_NOWAIT);
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if (IS_ERR(ciphertext_page)) {
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err = PTR_ERR(ciphertext_page);
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goto errout;
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@ -410,11 +414,12 @@ int ext4_encrypted_zeroout(struct inode *inode, ext4_lblk_t lblk,
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while (len--) {
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err = ext4_page_crypto(inode, EXT4_ENCRYPT, lblk,
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ZERO_PAGE(0), ciphertext_page);
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ZERO_PAGE(0), ciphertext_page,
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GFP_NOFS);
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if (err)
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goto errout;
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bio = bio_alloc(GFP_KERNEL, 1);
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bio = bio_alloc(GFP_NOWAIT, 1);
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if (!bio) {
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err = -ENOMEM;
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goto errout;
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@ -2282,11 +2282,13 @@ extern struct kmem_cache *ext4_crypt_info_cachep;
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bool ext4_valid_contents_enc_mode(uint32_t mode);
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uint32_t ext4_validate_encryption_key_size(uint32_t mode, uint32_t size);
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extern struct workqueue_struct *ext4_read_workqueue;
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struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode);
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struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode,
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gfp_t gfp_flags);
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void ext4_release_crypto_ctx(struct ext4_crypto_ctx *ctx);
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void ext4_restore_control_page(struct page *data_page);
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struct page *ext4_encrypt(struct inode *inode,
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struct page *plaintext_page);
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struct page *plaintext_page,
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gfp_t gfp_flags);
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int ext4_decrypt(struct page *page);
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int ext4_encrypted_zeroout(struct inode *inode, ext4_lblk_t lblk,
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ext4_fsblk_t pblk, ext4_lblk_t len);
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@ -23,6 +23,7 @@
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <linux/backing-dev.h>
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#include "ext4_jbd2.h"
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#include "xattr.h"
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@ -470,9 +471,20 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
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if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode) &&
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nr_to_submit) {
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data_page = ext4_encrypt(inode, page);
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gfp_t gfp_flags = GFP_NOFS;
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retry_encrypt:
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data_page = ext4_encrypt(inode, page, gfp_flags);
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if (IS_ERR(data_page)) {
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ret = PTR_ERR(data_page);
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if (ret == ENOMEM && wbc->sync_mode == WB_SYNC_ALL) {
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if (io->io_bio) {
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ext4_io_submit(io);
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congestion_wait(BLK_RW_ASYNC, HZ/50);
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}
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gfp_flags |= __GFP_NOFAIL;
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goto retry_encrypt;
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}
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data_page = NULL;
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goto out;
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}
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@ -279,7 +279,7 @@ int ext4_mpage_readpages(struct address_space *mapping,
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if (ext4_encrypted_inode(inode) &&
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S_ISREG(inode->i_mode)) {
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ctx = ext4_get_crypto_ctx(inode);
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ctx = ext4_get_crypto_ctx(inode, GFP_NOFS);
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if (IS_ERR(ctx))
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goto set_error_page;
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}
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