platform: msm: fix PFT when using direct-io

When read/write a file using dircet-io (O_DIRECT),
we can't get the inode from a bio by walking the path
bio->bi_io_vec->bv_page->mapping->host
since the page is anonymous and not mapped.
On the other more typical cases when not using O_DIRECT,
the page cache is used and the bv_page is available.

Change-Id: I349cad54a978ed9919f960d55f0f95c1e53262e5
Signed-off-by: Amir Samuelov <amirs@codeaurora.org>

drivers/md/dm-req-crypt.c

@@ -85,7 +85,6 @@ static  bool req_crypt_should_encrypt(struct req_dm_crypt_io *req)
 	int ret;
 	bool should_encrypt = false;
 	struct bio *bio = NULL;
-	struct inode *inode = NULL;
 	u32 key_id = 0;
 	bool is_encrypted = false;
 	bool is_inplace = false;
@@ -95,13 +94,7 @@ static  bool req_crypt_should_encrypt(struct req_dm_crypt_io *req)
 
 	bio = req->cloned_request->bio;
 
-	if (!bio->bi_io_vec || !bio->bi_io_vec->bv_page ||
-	    !bio->bi_io_vec->bv_page->mapping)
-		return false;
-
-	inode = bio->bi_io_vec->bv_page->mapping->host;
-
-	ret = pft_get_key_index(inode, &key_id, &is_encrypted, &is_inplace);
+	ret = pft_get_key_index(bio, &key_id, &is_encrypted, &is_inplace);
 	/* req->key_id = key_id; @todo support more than 1 pfe key */
 	if ((ret == 0) && (is_encrypted || is_inplace)) {
 		should_encrypt = true;
@@ -119,7 +112,6 @@ static  bool req_crypt_should_deccrypt(struct req_dm_crypt_io *req)
 	int ret;
 	bool should_deccrypt = false;
 	struct bio *bio = NULL;
-	struct inode *inode = NULL;
 	u32 key_id = 0;
 	bool is_encrypted = false;
 	bool is_inplace = false;
@@ -129,13 +121,7 @@ static  bool req_crypt_should_deccrypt(struct req_dm_crypt_io *req)
 
 	bio = req->cloned_request->bio;
 
-	if (!bio->bi_io_vec || !bio->bi_io_vec->bv_page ||
-	    !bio->bi_io_vec->bv_page->mapping)
-		return false;
-
-	inode = bio->bi_io_vec->bv_page->mapping->host;
-
-	ret = pft_get_key_index(inode, &key_id, &is_encrypted, &is_inplace);
+	ret = pft_get_key_index(bio, &key_id, &is_encrypted, &is_inplace);
 	/* req->key_id = key_id; @todo support more than 1 pfe key */
 	if ((ret == 0) && (is_encrypted && !is_inplace)) {
 		should_deccrypt = true;

drivers/platform/msm/pft.c

@@ -162,6 +162,8 @@ struct pft_device {
 /* Device Driver State */
 static struct pft_device *pft_dev;
 
+static struct inode *pft_bio_get_inode(struct bio *bio);
+
 /**
  * pft_is_ready() - driver is initialized and ready.
  *
@@ -623,10 +625,11 @@ static inline bool pft_is_inplace_file(struct file *filp)
  *
  * Return: 0 on successe, negative value on failure.
  */
-int pft_get_key_index(struct inode *inode, u32 *key_index,
+int pft_get_key_index(struct bio *bio, u32 *key_index,
 		      bool *is_encrypted, bool *is_inplace)
 {
 	u32 tag = 0;
+	struct inode *inode = NULL;
 
 	if (!pft_is_ready())
 		return -ENODEV;
@@ -634,7 +637,7 @@ int pft_get_key_index(struct inode *inode, u32 *key_index,
 	if (!selinux_is_enabled())
 		return -ENODEV;
 
-	if (!inode)
+	if (!bio)
 		return -EPERM;
 
 	if (!is_encrypted) {
@@ -650,6 +653,10 @@ int pft_get_key_index(struct inode *inode, u32 *key_index,
 		return -EPERM;
 	}
 
+	inode = pft_bio_get_inode(bio);
+	if (!inode)
+		return -EINVAL;
+
 	if (!pft_is_tag_valid(inode)) {
 		pr_debug("file %s, Tag not valid\n", inode_to_filename(inode));
 		return -EINVAL;
@@ -685,8 +692,27 @@ EXPORT_SYMBOL(pft_get_key_index);
  */
 static struct inode *pft_bio_get_inode(struct bio *bio)
 {
-	if (!bio || !bio->bi_io_vec || !bio->bi_io_vec->bv_page ||
-	    !bio->bi_io_vec->bv_page->mapping)
+	if (!bio)
+		return NULL;
+	if (!bio->bi_io_vec)
+		return NULL;
+	if (!bio->bi_io_vec->bv_page)
+		return NULL;
+
+	if (PageAnon(bio->bi_io_vec->bv_page)) {
+		struct inode *inode;
+
+		/* Using direct-io (O_DIRECT) without page cache */
+		inode = dio_bio_get_inode(bio);
+		pr_debug("inode on direct-io, inode = 0x%x.\n", (int) inode);
+
+		return inode;
+	}
+
+	if (!bio->bi_io_vec->bv_page->mapping)
+		return NULL;
+
+	if (!bio->bi_io_vec->bv_page->mapping->host)
 		return NULL;
 
 	return bio->bi_io_vec->bv_page->mapping->host;
@@ -715,12 +741,12 @@ bool pft_allow_merge_bio(struct bio *bio1, struct bio *bio2)
 	if (!pft_is_ready())
 		return true;
 
-	ret = pft_get_key_index(pft_bio_get_inode(bio1), &key_index1,
+	ret = pft_get_key_index(bio1, &key_index1,
 				&is_encrypted1, &is_inplace);
 	if (ret)
 		is_encrypted1 = false;
 
-	ret = pft_get_key_index(pft_bio_get_inode(bio2), &key_index2,
+	ret = pft_get_key_index(bio2, &key_index2,
 				&is_encrypted2, &is_inplace);
 	if (ret)
 		is_encrypted2 = false;
@@ -929,6 +955,9 @@ int pft_file_open(struct file *filp, const struct cred *cred)
 	if (!pft_is_ready())
 		return 0;
 
+	if (filp->f_flags & O_DIRECT)
+		pr_debug("file %s using O_DIRECT.\n", file_to_filename(filp));
+
 	/* do nothing for non-encrypted files */
 	if (!pft_is_encrypted_file(filp->f_dentry))
 		return 0;

fs/bio.c

@@ -540,6 +540,7 @@ void __bio_clone(struct bio *bio, struct bio *bio_src)
 	bio->bi_vcnt = bio_src->bi_vcnt;
 	bio->bi_size = bio_src->bi_size;
 	bio->bi_idx = bio_src->bi_idx;
+	bio->bi_dio_inode = bio_src->bi_dio_inode;
 }
 EXPORT_SYMBOL(__bio_clone);
 

fs/direct-io.c

@@ -380,6 +380,8 @@ static inline void dio_bio_submit(struct dio *dio, struct dio_submit *sdio)
 	if (dio->is_async && dio->rw == READ)
 		bio_set_pages_dirty(bio);
 
+	bio->bi_dio_inode = dio->inode;
+
 	if (sdio->submit_io)
 		sdio->submit_io(dio->rw, bio, dio->inode,
 			       sdio->logical_offset_in_bio);
@@ -391,6 +393,19 @@ static inline void dio_bio_submit(struct dio *dio, struct dio_submit *sdio)
 	sdio->logical_offset_in_bio = 0;
 }
 
+struct inode *dio_bio_get_inode(struct bio *bio)
+{
+	struct inode *inode = NULL;
+
+	if (bio == NULL)
+		return NULL;
+
+	inode = bio->bi_dio_inode;
+
+	return inode;
+}
+EXPORT_SYMBOL(dio_bio_get_inode);
+
 /*
  * Release any resources in case of a failure
  */

include/linux/blk_types.h

@@ -74,6 +74,13 @@ struct bio {
 	struct bio_integrity_payload *bi_integrity;  /* data integrity */
 #endif
 
+	/*
+	 * When using dircet-io (O_DIRECT), we can't get the inode from a bio
+	 * by walking bio->bi_io_vec->bv_page->mapping->host
+	 * since the page is anon.
+	 */
+	struct inode		*bi_dio_inode;
+
 	/*
 	 * Everything starting with bi_max_vecs will be preserved by bio_reset()
 	 */

include/linux/fs.h

@@ -2455,6 +2455,7 @@ enum {
 
 void dio_end_io(struct bio *bio, int error);
 
+
 ssize_t __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 	struct block_device *bdev, const struct iovec *iov, loff_t offset,
 	unsigned long nr_segs, get_block_t get_block, dio_iodone_t end_io,
@@ -2472,6 +2473,7 @@ static inline ssize_t blockdev_direct_IO(int rw, struct kiocb *iocb,
 
 void inode_dio_wait(struct inode *inode);
 void inode_dio_done(struct inode *inode);
+struct inode *dio_bio_get_inode(struct bio *bio);
 
 extern const struct file_operations generic_ro_fops;
 

include/linux/pft.h

@@ -15,11 +15,12 @@
 
 #include <linux/types.h>
 #include <linux/fs.h>
+#include <linux/bio.h>
 
 #ifdef CONFIG_PFT
 
 /* dm-req-crypt API */
-int pft_get_key_index(struct inode *inode, u32 *key_index,
+int pft_get_key_index(struct bio *bio, u32 *key_index,
 		      bool *is_encrypted, bool *is_inplace);
 
 /* block layer API */
@@ -49,7 +50,7 @@ int pft_inode_set_xattr(struct dentry *dentry, const char *name);
 
 
 #else
-static inline int pft_get_key_index(struct inode *inode, u32 *key_index,
+static inline int pft_get_key_index(struct bio *bio, u32 *key_index,
 				    bool *is_encrypted, bool *is_inplace)
 { return -ENODEV; }