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From: Gerhard Heift <gerhard@heift.name>
To: linux-btrfs@vger.kernel.org
Subject: [PATCH RFCv4 4/7] btrfs: tree_search, copy_to_sk: return needed size on EOVERFLOW
Date: Thu, 30 Jan 2014 16:24:00 +0100	[thread overview]
Message-ID: <1391095443-20287-5-git-send-email-Gerhard@Heift.Name> (raw)
In-Reply-To: <1391095443-20287-1-git-send-email-Gerhard@Heift.Name>

If an item in tree_search is too large to be stored in the given buffer, return
the needed size (including the header).

Signed-off-by: Gerhard Heift <Gerhard@Heift.Name>
---
 fs/btrfs/ioctl.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 4e32ac2..1180293 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1854,7 +1854,7 @@ static noinline int copy_to_sk(struct btrfs_root *root,
 			       struct btrfs_path *path,
 			       struct btrfs_key *key,
 			       struct btrfs_ioctl_search_key *sk,
-			       size_t buf_size,
+			       size_t *buf_size,
 			       char *buf,
 			       unsigned long *sk_offset,
 			       int *num_found)
@@ -1887,7 +1887,7 @@ static noinline int copy_to_sk(struct btrfs_root *root,
 		if (!key_in_sk(key, sk))
 			continue;
 
-		if (sizeof(sh) + item_len > buf_size) {
+		if (sizeof(sh) + item_len > *buf_size) {
 			if (*num_found) {
 				ret = 1;
 				goto out;
@@ -1898,11 +1898,12 @@ static noinline int copy_to_sk(struct btrfs_root *root,
 			 * handle -EOVERFLOW
 			 */
 
+			*buf_size = sizeof(sh) + item_len;
 			item_len = 0;
 			ret = -EOVERFLOW;
 		}
 
-		if (sizeof(sh) + item_len + *sk_offset > buf_size) {
+		if (sizeof(sh) + item_len + *sk_offset > *buf_size) {
 			ret = 1;
 			goto out;
 		}
@@ -1953,7 +1954,7 @@ out:
 
 static noinline int search_ioctl(struct inode *inode,
 				 struct btrfs_ioctl_search_key *sk,
-				 size_t buf_size,
+				 size_t *buf_size,
 				 char *buf)
 {
 	struct btrfs_root *root;
@@ -1964,8 +1965,10 @@ static noinline int search_ioctl(struct inode *inode,
 	int num_found = 0;
 	unsigned long sk_offset = 0;
 
-	if (buf_size < sizeof(struct btrfs_ioctl_search_header))
+	if (*buf_size < sizeof(struct btrfs_ioctl_search_header)) {
+		*buf_size = sizeof(struct btrfs_ioctl_search_header);
 		return -EOVERFLOW;
+	}
 
 	path = btrfs_alloc_path();
 	if (!path)
@@ -2018,9 +2021,10 @@ err:
 static noinline int btrfs_ioctl_tree_search(struct file *file,
 					   void __user *argp)
 {
-	 struct btrfs_ioctl_search_args *args;
-	 struct inode *inode;
-	 int ret;
+	struct btrfs_ioctl_search_args *args;
+	struct inode *inode;
+	int ret;
+	size_t buf_size;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
@@ -2029,8 +2033,10 @@ static noinline int btrfs_ioctl_tree_search(struct file *file,
 	if (IS_ERR(args))
 		return PTR_ERR(args);
 
+	buf_size = sizeof(args->buf);
+
 	inode = file_inode(file);
-	ret = search_ioctl(inode, &args->key, sizeof(args->buf), args->buf);
+	ret = search_ioctl(inode, &args->key, &buf_size, args->buf);
 
 	/*
 	 * In the origin implementation an overflow is handled by returning a
-- 
1.8.5.3


  parent reply	other threads:[~2014-01-30 15:24 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-30 15:23 [PATCH RFCv4] new ioctl TREE_SEARCH_V2 Gerhard Heift
2014-01-30 15:23 ` [PATCH RFCv4 1/7] btrfs: tree_search: eliminate redundant nr_items check Gerhard Heift
2014-01-30 15:23 ` [PATCH RFCv4 2/7] btrfs: tree_search, search_ioctl: accept varying buffer Gerhard Heift
2014-01-30 15:23 ` [PATCH RFCv4 3/7] btrfs: tree_search, copy_to_sk: return EOVERFLOW for too small buffer Gerhard Heift
2014-01-30 15:24 ` Gerhard Heift [this message]
2014-01-30 15:24 ` [PATCH RFCv4 5/7] btrfs: new function read_extent_buffer_to_user Gerhard Heift
2014-01-30 15:24 ` [PATCH RFCv4 6/7] btrfs: tree_search, search_ioctl: direct copy to userspace Gerhard Heift
2014-01-30 15:24 ` [PATCH RFCv4 7/7] btrfs: new ioctl TREE_SEARCH_V2 Gerhard Heift
2014-01-31 17:40 ` [PATCH RFCv4] " David Sterba
2014-04-04 11:36 ` David Sterba

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