From: Al Viro <viro@zeniv.linux.org.uk>
Date: Thu, 9 Apr 2015 16:55:47 +0000 (-0400)
Subject: switch generic_write_checks() to iocb and iter
X-Git-Tag: omap-for-v4.2/o2_dc~106^2~11
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3309dd04cbcd2cdad168485af5cf3576b5051e49;p=pandora-kernel.git

switch generic_write_checks() to iocb and iter

... returning -E... upon error and amount of data left in iter after
(possible) truncation upon success.  Note, that normal case gives
a non-zero (positive) return value, so any tests for != 0 _must_ be
updated.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Conflicts:
	fs/ext4/file.c
---

diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index b5b020ace1b3..2a9dd37dc426 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -404,21 +404,16 @@ static ssize_t
 v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
-	ssize_t retval = 0;
-	loff_t origin = iocb->ki_pos;
-	size_t count = iov_iter_count(from);
+	ssize_t retval;
+	loff_t origin;
 	int err = 0;
 
-	retval = generic_write_checks(file, &origin, &count);
-	if (retval)
+	retval = generic_write_checks(iocb, from);
+	if (retval <= 0)
 		return retval;
 
-	iov_iter_truncate(from, count);
-
-	if (!count)
-		return 0;
-
-	retval = p9_client_write(file->private_data, origin, from, &err);
+	origin = iocb->ki_pos;
+	retval = p9_client_write(file->private_data, iocb->ki_pos, from, &err);
 	if (retval > 0) {
 		struct inode *inode = file_inode(file);
 		loff_t i_size;
@@ -428,12 +423,11 @@ v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		if (inode->i_mapping && inode->i_mapping->nrpages)
 			invalidate_inode_pages2_range(inode->i_mapping,
 						      pg_start, pg_end);
-		origin += retval;
+		iocb->ki_pos += retval;
 		i_size = i_size_read(inode);
-		iocb->ki_pos = origin;
-		if (origin > i_size) {
-			inode_add_bytes(inode, origin - i_size);
-			i_size_write(inode, origin);
+		if (iocb->ki_pos > i_size) {
+			inode_add_bytes(inode, iocb->ki_pos - i_size);
+			i_size_write(inode, iocb->ki_pos);
 		}
 		return retval;
 	}
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 691a84a81e09..c64d11c41eeb 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1739,27 +1739,19 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
 	u64 start_pos;
 	u64 end_pos;
 	ssize_t num_written = 0;
-	ssize_t err = 0;
-	size_t count = iov_iter_count(from);
 	bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
-	loff_t pos = iocb->ki_pos;
+	ssize_t err;
+	loff_t pos;
+	size_t count;
 
 	mutex_lock(&inode->i_mutex);
-
-	current->backing_dev_info = inode_to_bdi(inode);
-	err = generic_write_checks(file, &pos, &count);
-	if (err) {
+	err = generic_write_checks(iocb, from);
+	if (err <= 0) {
 		mutex_unlock(&inode->i_mutex);
-		goto out;
-	}
-
-	if (count == 0) {
-		mutex_unlock(&inode->i_mutex);
-		goto out;
+		return err;
 	}
 
-	iov_iter_truncate(from, count);
-
+	current->backing_dev_info = inode_to_bdi(inode);
 	err = file_remove_suid(file);
 	if (err) {
 		mutex_unlock(&inode->i_mutex);
@@ -1786,6 +1778,8 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
 	 */
 	update_time_for_write(inode);
 
+	pos = iocb->ki_pos;
+	count = iov_iter_count(from);
 	start_pos = round_down(pos, root->sectorsize);
 	if (start_pos > i_size_read(inode)) {
 		/* Expand hole size to cover write data, preventing empty gap */
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 761841903160..3f0b9339d823 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -941,9 +941,9 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_osd_client *osdc =
 		&ceph_sb_to_client(inode->i_sb)->client->osdc;
-	ssize_t count = iov_iter_count(from), written = 0;
+	ssize_t count, written = 0;
 	int err, want, got;
-	loff_t pos = iocb->ki_pos;
+	loff_t pos;
 
 	if (ceph_snap(inode) != CEPH_NOSNAP)
 		return -EROFS;
@@ -953,14 +953,12 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	/* We can write back this queue in page reclaim */
 	current->backing_dev_info = inode_to_bdi(inode);
 
-	err = generic_write_checks(file, &pos, &count);
-	if (err)
-		goto out;
-
-	if (count == 0)
+	err = generic_write_checks(iocb, from);
+	if (err <= 0)
 		goto out;
-	iov_iter_truncate(from, count);
 
+	pos = iocb->ki_pos;
+	count = iov_iter_count(from);
 	err = file_remove_suid(file);
 	if (err)
 		goto out;
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 4202e74b2db5..ca2bc5406306 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2563,7 +2563,6 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
 ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
-	size_t len;
 	ssize_t total_written = 0;
 	struct cifsFileInfo *open_file;
 	struct cifs_tcon *tcon;
@@ -2579,16 +2578,10 @@ ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
 	 * write request.
 	 */
 
-	len = iov_iter_count(from);
-	rc = generic_write_checks(file, &iocb->ki_pos, &len);
-	if (rc)
+	rc = generic_write_checks(iocb, from);
+	if (rc <= 0)
 		return rc;
 
-	if (!len)
-		return 0;
-
-	iov_iter_truncate(from, len);
-
 	INIT_LIST_HEAD(&wdata_list);
 	cifs_sb = CIFS_FILE_SB(file);
 	open_file = file->private_data;
@@ -2599,8 +2592,8 @@ ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
 
 	memcpy(&saved_from, from, sizeof(struct iov_iter));
 
-	rc = cifs_write_from_iter(iocb->ki_pos, len, from, open_file, cifs_sb,
-				  &wdata_list);
+	rc = cifs_write_from_iter(iocb->ki_pos, iov_iter_count(from), from,
+				  open_file, cifs_sb, &wdata_list);
 
 	/*
 	 * If at least one write was successfully sent, then discard any rc
@@ -2674,7 +2667,6 @@ cifs_writev(struct kiocb *iocb, struct iov_iter *from)
 	struct cifsInodeInfo *cinode = CIFS_I(inode);
 	struct TCP_Server_Info *server = tlink_tcon(cfile->tlink)->ses->server;
 	ssize_t rc;
-	size_t count;
 
 	/*
 	 * We need to hold the sem to be sure nobody modifies lock list
@@ -2683,16 +2675,10 @@ cifs_writev(struct kiocb *iocb, struct iov_iter *from)
 	down_read(&cinode->lock_sem);
 	mutex_lock(&inode->i_mutex);
 
-	count = iov_iter_count(from);
-	rc = generic_write_checks(file, &iocb->ki_pos, &count);
-	if (rc)
+	rc = generic_write_checks(iocb, from);
+	if (rc <= 0)
 		goto out;
 
-	if (count == 0)
-		goto out;
-
-	iov_iter_truncate(from, count);
-
 	if (!cifs_find_lock_conflict(cfile, iocb->ki_pos, iov_iter_count(from),
 				     server->vals->exclusive_lock_type, NULL,
 				     CIFS_WRITE_OP))
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