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Subject[PATCH 04/73] VFS: Make lookup_hash() return a struct path [ver #2]
Date
Signed-off-by: Jan Blunck <jblunck@suse.de> (Original author)
Signed-off-by: Valerie Aurora <vaurora@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com> (Forward porting)
---
fs/namei.c | 121 +++++++++++++++++++++++++++++++-----------------------------
1 files changed, 62 insertions(+), 59 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 4dc0e1d..2d983f7 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1766,9 +1766,20 @@ static struct dentry *__lookup_hash(struct qstr *name,
* needs parent already locked. Doesn't follow mounts.
* SMP-safe.
*/
-static struct dentry *lookup_hash(struct nameidata *nd)
+static int lookup_hash(struct nameidata *nd, struct qstr *name,
+ struct path *path)
{
- return __lookup_hash(&nd->last, nd->path.dentry, nd);
+ struct dentry *result;
+
+ result = __lookup_hash(name, nd->path.dentry, nd);
+ if (IS_ERR(result)) {
+ path->mnt = NULL;
+ path->dentry = NULL;
+ return PTR_ERR(result);
+ }
+ path->mnt = nd->path.mnt;
+ path->dentry = result;
+ return 0;
}

/**
@@ -2098,7 +2109,6 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
const struct open_flags *op, const char *pathname)
{
struct dentry *dir = nd->path.dentry;
- struct dentry *dentry;
int open_flag = op->open_flag;
int will_truncate = open_flag & O_TRUNC;
int want_write = 0;
@@ -2178,18 +2188,14 @@ static struct file *do_last(struct nameidata *nd, struct path *path,

mutex_lock(&dir->d_inode->i_mutex);

- dentry = lookup_hash(nd);
- error = PTR_ERR(dentry);
- if (IS_ERR(dentry)) {
+ error = lookup_hash(nd, &nd->last, path);
+ if (error) {
mutex_unlock(&dir->d_inode->i_mutex);
goto exit;
}

- path->dentry = dentry;
- path->mnt = nd->path.mnt;
-
/* Negative dentry, just create the file */
- if (!dentry->d_inode) {
+ if (!path->dentry->d_inode) {
umode_t mode = op->mode;
if (!IS_POSIXACL(dir->d_inode))
mode &= ~current_umask();
@@ -2208,15 +2214,15 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
open_flag &= ~O_TRUNC;
will_truncate = 0;
acc_mode = MAY_OPEN;
- error = security_path_mknod(&nd->path, dentry, mode, 0);
+ error = security_path_mknod(&nd->path, path->dentry, mode, 0);
if (error)
goto exit_mutex_unlock;
- error = vfs_create(dir->d_inode, dentry, mode, nd);
+ error = vfs_create(dir->d_inode, path->dentry, mode, nd);
if (error)
goto exit_mutex_unlock;
mutex_unlock(&dir->d_inode->i_mutex);
dput(nd->path.dentry);
- nd->path.dentry = dentry;
+ nd->path.dentry = path->dentry;
goto common;
}

@@ -2395,8 +2401,8 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,

struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path, int is_dir)
{
- struct dentry *dentry = ERR_PTR(-EEXIST);
struct nameidata nd;
+ struct path new_path;
int error = do_path_lookup(dfd, pathname, LOOKUP_PARENT, &nd);
if (error)
return ERR_PTR(error);
@@ -2405,6 +2411,7 @@ struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path
* Yucky last component or no last component at all?
* (foo/., foo/.., /////)
*/
+ error = -EEXIST;
if (nd.last_type != LAST_NORM)
goto out;
nd.flags &= ~LOOKUP_PARENT;
@@ -2415,11 +2422,11 @@ struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path
* Do the final lookup.
*/
mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
- dentry = lookup_hash(&nd);
- if (IS_ERR(dentry))
+ error = lookup_hash(&nd, &nd.last, &new_path);
+ if (error)
goto fail;

- if (dentry->d_inode)
+ if (new_path.dentry->d_inode)
goto eexist;
/*
* Special case - lookup gave negative, but... we had foo/bar/
@@ -2428,20 +2435,20 @@ struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path
* been asking for (non-existent) directory. -ENOENT for you.
*/
if (unlikely(!is_dir && nd.last.name[nd.last.len])) {
- dput(dentry);
- dentry = ERR_PTR(-ENOENT);
- goto fail;
+ error = -ENOENT;
+ goto fail_do_put;
}
*path = nd.path;
- return dentry;
+ return new_path.dentry;
eexist:
- dput(dentry);
- dentry = ERR_PTR(-EEXIST);
+ error = -EEXIST;
+fail_do_put:
+ dput(new_path.dentry);
fail:
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
out:
path_put(&nd.path);
- return dentry;
+ return ERR_PTR(error);
}
EXPORT_SYMBOL(kern_path_create);

@@ -2673,7 +2680,7 @@ static long do_rmdir(int dfd, const char __user *pathname)
{
int error = 0;
char * name;
- struct dentry *dentry;
+ struct path path;
struct nameidata nd;

error = user_path_parent(dfd, pathname, &nd, &name);
@@ -2695,25 +2702,24 @@ static long do_rmdir(int dfd, const char __user *pathname)
nd.flags &= ~LOOKUP_PARENT;

mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
- dentry = lookup_hash(&nd);
- error = PTR_ERR(dentry);
- if (IS_ERR(dentry))
+ error = lookup_hash(&nd, &nd.last, &path);
+ if (error)
goto exit2;
- if (!dentry->d_inode) {
+ if (!path.dentry->d_inode) {
error = -ENOENT;
goto exit3;
}
error = mnt_want_write(nd.path.mnt);
if (error)
goto exit3;
- error = security_path_rmdir(&nd.path, dentry);
+ error = security_path_rmdir(&nd.path, path.dentry);
if (error)
goto exit4;
- error = vfs_rmdir(nd.path.dentry->d_inode, dentry);
+ error = vfs_rmdir(nd.path.dentry->d_inode, path.dentry);
exit4:
mnt_drop_write(nd.path.mnt);
exit3:
- dput(dentry);
+ path_put_conditional(&path, &nd);
exit2:
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
exit1:
@@ -2769,7 +2775,7 @@ static long do_unlinkat(int dfd, const char __user *pathname)
{
int error;
char *name;
- struct dentry *dentry;
+ struct path path;
struct nameidata nd;
struct inode *inode = NULL;

@@ -2784,27 +2790,26 @@ static long do_unlinkat(int dfd, const char __user *pathname)
nd.flags &= ~LOOKUP_PARENT;

mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
- dentry = lookup_hash(&nd);
- error = PTR_ERR(dentry);
- if (!IS_ERR(dentry)) {
+ error = lookup_hash(&nd, &nd.last, &path);
+ if (!error) {
/* Why not before? Because we want correct error value */
if (nd.last.name[nd.last.len])
goto slashes;
- inode = dentry->d_inode;
+ inode = path.dentry->d_inode;
if (!inode)
goto slashes;
ihold(inode);
error = mnt_want_write(nd.path.mnt);
if (error)
goto exit2;
- error = security_path_unlink(&nd.path, dentry);
+ error = security_path_unlink(&nd.path, path.dentry);
if (error)
goto exit3;
- error = vfs_unlink(nd.path.dentry->d_inode, dentry);
+ error = vfs_unlink(nd.path.dentry->d_inode, path.dentry);
exit3:
mnt_drop_write(nd.path.mnt);
exit2:
- dput(dentry);
+ path_put_conditional(&path, &nd);
}
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
if (inode)
@@ -2815,8 +2820,8 @@ exit1:
return error;

slashes:
- error = !dentry->d_inode ? -ENOENT :
- S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR;
+ error = !path.dentry->d_inode ? -ENOENT :
+ S_ISDIR(path.dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR;
goto exit2;
}

@@ -3156,7 +3161,7 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
int, newdfd, const char __user *, newname)
{
struct dentry *old_dir, *new_dir;
- struct dentry *old_dentry, *new_dentry;
+ struct path old, new;
struct dentry *trap;
struct nameidata oldnd, newnd;
char *from;
@@ -3190,16 +3195,15 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,

trap = lock_rename(new_dir, old_dir);

- old_dentry = lookup_hash(&oldnd);
- error = PTR_ERR(old_dentry);
- if (IS_ERR(old_dentry))
+ error = lookup_hash(&oldnd, &oldnd.last, &old);
+ if (error)
goto exit3;
/* source must exist */
error = -ENOENT;
- if (!old_dentry->d_inode)
+ if (!old.dentry->d_inode)
goto exit4;
/* unless the source is a directory trailing slashes give -ENOTDIR */
- if (!S_ISDIR(old_dentry->d_inode->i_mode)) {
+ if (!S_ISDIR(old.dentry->d_inode->i_mode)) {
error = -ENOTDIR;
if (oldnd.last.name[oldnd.last.len])
goto exit4;
@@ -3208,32 +3212,31 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
}
/* source should not be ancestor of target */
error = -EINVAL;
- if (old_dentry == trap)
+ if (old.dentry == trap)
goto exit4;
- new_dentry = lookup_hash(&newnd);
- error = PTR_ERR(new_dentry);
- if (IS_ERR(new_dentry))
+ error = lookup_hash(&newnd, &newnd.last, &new);
+ if (error)
goto exit4;
/* target should not be an ancestor of source */
error = -ENOTEMPTY;
- if (new_dentry == trap)
+ if (new.dentry == trap)
goto exit5;

error = mnt_want_write(oldnd.path.mnt);
if (error)
goto exit5;
- error = security_path_rename(&oldnd.path, old_dentry,
- &newnd.path, new_dentry);
+ error = security_path_rename(&oldnd.path, old.dentry,
+ &newnd.path, new.dentry);
if (error)
goto exit6;
- error = vfs_rename(old_dir->d_inode, old_dentry,
- new_dir->d_inode, new_dentry);
+ error = vfs_rename(old_dir->d_inode, old.dentry,
+ new_dir->d_inode, new.dentry);
exit6:
mnt_drop_write(oldnd.path.mnt);
exit5:
- dput(new_dentry);
+ path_put_conditional(&new, &newnd);
exit4:
- dput(old_dentry);
+ path_put_conditional(&old, &oldnd);
exit3:
unlock_rename(new_dir, old_dir);
exit2:


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