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Subject[PATCH v3 002/110] 9p: don't bother with __getname() in ->follow_link()
Date
From: Al Viro <viro@zeniv.linux.org.uk>

We copy there a kmalloc'ed string and proceed to kfree that string immediately
after that. Easier to just feed that string to nd_set_link() and _not_
kfree it until ->put_link() (which becomes kfree_put_link() in that case).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/9p/v9fs.h | 2 --
fs/9p/vfs_inode.c | 93 ++++++++++----------------------------------------
fs/9p/vfs_inode_dotl.c | 31 +++++------------
3 files changed, 26 insertions(+), 100 deletions(-)

diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index fb9ffcb..0923f2c 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -149,8 +149,6 @@ extern int v9fs_vfs_unlink(struct inode *i, struct dentry *d);
extern int v9fs_vfs_rmdir(struct inode *i, struct dentry *d);
extern int v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry);
-extern void v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd,
- void *p);
extern struct inode *v9fs_inode_from_fid(struct v9fs_session_info *v9ses,
struct p9_fid *fid,
struct super_block *sb, int new);
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index cda68f7..0ba1171 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -1224,103 +1224,46 @@ ino_t v9fs_qid2ino(struct p9_qid *qid)
}

/**
- * v9fs_readlink - read a symlink's location (internal version)
+ * v9fs_vfs_follow_link - follow a symlink path
* @dentry: dentry for symlink
- * @buffer: buffer to load symlink location into
- * @buflen: length of buffer
+ * @nd: nameidata
*
*/

-static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
+static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
{
- int retval;
-
- struct v9fs_session_info *v9ses;
- struct p9_fid *fid;
+ struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry);
+ struct p9_fid *fid = v9fs_fid_lookup(dentry);
struct p9_wstat *st;

- p9_debug(P9_DEBUG_VFS, " %pd\n", dentry);
- retval = -EPERM;
- v9ses = v9fs_dentry2v9ses(dentry);
- fid = v9fs_fid_lookup(dentry);
+ p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
+
if (IS_ERR(fid))
- return PTR_ERR(fid);
+ return ERR_CAST(fid);

if (!v9fs_proto_dotu(v9ses))
- return -EBADF;
+ return ERR_PTR(-EBADF);

st = p9_client_stat(fid);
if (IS_ERR(st))
- return PTR_ERR(st);
+ return ERR_CAST(st);

if (!(st->mode & P9_DMSYMLINK)) {
- retval = -EINVAL;
- goto done;
+ p9stat_free(st);
+ kfree(st);
+ return ERR_PTR(-EINVAL);
}
+ if (strlen(st->extension) >= PATH_MAX)
+ st->extension[PATH_MAX - 1] = '\0';

- /* copy extension buffer into buffer */
- retval = min(strlen(st->extension)+1, (size_t)buflen);
- memcpy(buffer, st->extension, retval);
-
- p9_debug(P9_DEBUG_VFS, "%pd -> %s (%.*s)\n",
- dentry, st->extension, buflen, buffer);
-
-done:
+ nd_set_link(nd, st->extension);
+ st->extension = NULL;
p9stat_free(st);
kfree(st);
- return retval;
-}
-
-/**
- * v9fs_vfs_follow_link - follow a symlink path
- * @dentry: dentry for symlink
- * @nd: nameidata
- *
- */
-
-static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
-{
- int len = 0;
- char *link = __getname();
-
- p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
-
- if (!link)
- link = ERR_PTR(-ENOMEM);
- else {
- len = v9fs_readlink(dentry, link, PATH_MAX);
-
- if (len < 0) {
- __putname(link);
- link = ERR_PTR(len);
- } else
- link[min(len, PATH_MAX-1)] = 0;
- }
- nd_set_link(nd, link);
-
return NULL;
}

/**
- * v9fs_vfs_put_link - release a symlink path
- * @dentry: dentry for symlink
- * @nd: nameidata
- * @p: unused
- *
- */
-
-void
-v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
-{
- char *s = nd_get_link(nd);
-
- p9_debug(P9_DEBUG_VFS, " %pd %s\n",
- dentry, IS_ERR(s) ? "<error>" : s);
- if (!IS_ERR(s))
- __putname(s);
-}
-
-/**
* v9fs_vfs_mkspecial - create a special file
* @dir: inode to create special file in
* @dentry: dentry to create
@@ -1514,7 +1457,7 @@ static const struct inode_operations v9fs_file_inode_operations = {
static const struct inode_operations v9fs_symlink_inode_operations = {
.readlink = generic_readlink,
.follow_link = v9fs_vfs_follow_link,
- .put_link = v9fs_vfs_put_link,
+ .put_link = kfree_put_link,
.getattr = v9fs_vfs_getattr,
.setattr = v9fs_vfs_setattr,
};
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index 9861c7c..bc2a91f 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -912,33 +912,18 @@ error:
static void *
v9fs_vfs_follow_link_dotl(struct dentry *dentry, struct nameidata *nd)
{
- int retval;
- struct p9_fid *fid;
- char *link = __getname();
+ struct p9_fid *fid = v9fs_fid_lookup(dentry);
char *target;
+ int retval;

p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);

- if (!link) {
- link = ERR_PTR(-ENOMEM);
- goto ndset;
- }
- fid = v9fs_fid_lookup(dentry);
- if (IS_ERR(fid)) {
- __putname(link);
- link = ERR_CAST(fid);
- goto ndset;
- }
+ if (IS_ERR(fid))
+ return ERR_CAST(fid);
retval = p9_client_readlink(fid, &target);
- if (!retval) {
- strcpy(link, target);
- kfree(target);
- goto ndset;
- }
- __putname(link);
- link = ERR_PTR(retval);
-ndset:
- nd_set_link(nd, link);
+ if (retval)
+ return ERR_PTR(retval);
+ nd_set_link(nd, target);
return NULL;
}

@@ -1006,7 +991,7 @@ const struct inode_operations v9fs_file_inode_operations_dotl = {
const struct inode_operations v9fs_symlink_inode_operations_dotl = {
.readlink = generic_readlink,
.follow_link = v9fs_vfs_follow_link_dotl,
- .put_link = v9fs_vfs_put_link,
+ .put_link = kfree_put_link,
.getattr = v9fs_vfs_getattr_dotl,
.setattr = v9fs_vfs_setattr_dotl,
.setxattr = generic_setxattr,
--
2.1.4


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