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-rw-r--r--fs/open.c211
1 files changed, 65 insertions, 146 deletions
diff --git a/fs/open.c b/fs/open.c
index 1540632..1e914b3 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -537,25 +537,6 @@ static int chown_common(struct path *path, uid_t user, gid_t group)
return error;
}
-SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
-{
- struct path path;
- int error;
-
- error = user_path(filename, &path);
- if (error)
- goto out;
- error = mnt_want_write(path.mnt);
- if (error)
- goto out_release;
- error = chown_common(&path, user, group);
- mnt_drop_write(path.mnt);
-out_release:
- path_put(&path);
-out:
- return error;
-}
-
SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
gid_t, group, int, flag)
{
@@ -583,23 +564,15 @@ out:
return error;
}
-SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
+SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
{
- struct path path;
- int error;
+ return sys_fchownat(AT_FDCWD, filename, user, group, 0);
+}
- error = user_lpath(filename, &path);
- if (error)
- goto out;
- error = mnt_want_write(path.mnt);
- if (error)
- goto out_release;
- error = chown_common(&path, user, group);
- mnt_drop_write(path.mnt);
-out_release:
- path_put(&path);
-out:
- return error;
+SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
+{
+ return sys_fchownat(AT_FDCWD, filename, user, group,
+ AT_SYMLINK_NOFOLLOW);
}
SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
@@ -667,10 +640,9 @@ int open_check_o_direct(struct file *f)
return 0;
}
-static struct file *do_dentry_open(struct dentry *dentry, struct vfsmount *mnt,
- struct file *f,
- int (*open)(struct inode *, struct file *),
- const struct cred *cred)
+static int do_dentry_open(struct file *f,
+ int (*open)(struct inode *, struct file *),
+ const struct cred *cred)
{
static const struct file_operations empty_fops = {};
struct inode *inode;
@@ -682,9 +654,9 @@ static struct file *do_dentry_open(struct dentry *dentry, struct vfsmount *mnt,
if (unlikely(f->f_flags & O_PATH))
f->f_mode = FMODE_PATH;
- inode = dentry->d_inode;
+ inode = f->f_path.dentry->d_inode;
if (f->f_mode & FMODE_WRITE) {
- error = __get_file_write_access(inode, mnt);
+ error = __get_file_write_access(inode, f->f_path.mnt);
if (error)
goto cleanup_file;
if (!special_file(inode->i_mode))
@@ -692,14 +664,12 @@ static struct file *do_dentry_open(struct dentry *dentry, struct vfsmount *mnt,
}
f->f_mapping = inode->i_mapping;
- f->f_path.dentry = dentry;
- f->f_path.mnt = mnt;
f->f_pos = 0;
file_sb_list_add(f, inode->i_sb);
if (unlikely(f->f_mode & FMODE_PATH)) {
f->f_op = &empty_fops;
- return f;
+ return 0;
}
f->f_op = fops_get(inode->i_fop);
@@ -726,10 +696,11 @@ static struct file *do_dentry_open(struct dentry *dentry, struct vfsmount *mnt,
file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
- return f;
+ return 0;
cleanup_all:
fops_put(f->f_op);
+ file_sb_list_del(f);
if (f->f_mode & FMODE_WRITE) {
put_write_access(inode);
if (!special_file(inode->i_mode)) {
@@ -740,124 +711,62 @@ cleanup_all:
* here, so just reset the state.
*/
file_reset_write(f);
- mnt_drop_write(mnt);
+ mnt_drop_write(f->f_path.mnt);
}
}
- file_sb_list_del(f);
- f->f_path.dentry = NULL;
- f->f_path.mnt = NULL;
cleanup_file:
- dput(dentry);
- mntput(mnt);
- return ERR_PTR(error);
-}
-
-static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
- struct file *f,
- int (*open)(struct inode *, struct file *),
- const struct cred *cred)
-{
- struct file *res = do_dentry_open(dentry, mnt, f, open, cred);
- if (!IS_ERR(res)) {
- int error = open_check_o_direct(f);
- if (error) {
- fput(res);
- res = ERR_PTR(error);
- }
- } else {
- put_filp(f);
- }
- return res;
+ path_put(&f->f_path);
+ f->f_path.mnt = NULL;
+ f->f_path.dentry = NULL;
+ return error;
}
/**
- * lookup_instantiate_filp - instantiates the open intent filp
- * @nd: pointer to nameidata
+ * finish_open - finish opening a file
+ * @od: opaque open data
* @dentry: pointer to dentry
* @open: open callback
*
- * Helper for filesystems that want to use lookup open intents and pass back
- * a fully instantiated struct file to the caller.
- * This function is meant to be called from within a filesystem's
- * lookup method.
- * Beware of calling it for non-regular files! Those ->open methods might block
- * (e.g. in fifo_open), leaving you with parent locked (and in case of fifo,
- * leading to a deadlock, as nobody can open that fifo anymore, because
- * another process to open fifo will block on locked parent when doing lookup).
- * Note that in case of error, nd->intent.open.file is destroyed, but the
- * path information remains valid.
+ * This can be used to finish opening a file passed to i_op->atomic_open().
+ *
* If the open callback is set to NULL, then the standard f_op->open()
* filesystem callback is substituted.
*/
-struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
- int (*open)(struct inode *, struct file *))
+int finish_open(struct file *file, struct dentry *dentry,
+ int (*open)(struct inode *, struct file *),
+ int *opened)
{
- const struct cred *cred = current_cred();
+ int error;
+ BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
- if (IS_ERR(nd->intent.open.file))
- goto out;
- if (IS_ERR(dentry))
- goto out_err;
- nd->intent.open.file = __dentry_open(dget(dentry), mntget(nd->path.mnt),
- nd->intent.open.file,
- open, cred);
-out:
- return nd->intent.open.file;
-out_err:
- release_open_intent(nd);
- nd->intent.open.file = ERR_CAST(dentry);
- goto out;
+ mntget(file->f_path.mnt);
+ file->f_path.dentry = dget(dentry);
+
+ error = do_dentry_open(file, open, current_cred());
+ if (!error)
+ *opened |= FILE_OPENED;
+
+ return error;
}
-EXPORT_SYMBOL_GPL(lookup_instantiate_filp);
+EXPORT_SYMBOL(finish_open);
/**
- * nameidata_to_filp - convert a nameidata to an open filp.
- * @nd: pointer to nameidata
- * @flags: open flags
+ * finish_no_open - finish ->atomic_open() without opening the file
+ *
+ * @od: opaque open data
+ * @dentry: dentry or NULL (as returned from ->lookup())
*
- * Note that this function destroys the original nameidata
+ * This can be used to set the result of a successful lookup in ->atomic_open().
+ * The filesystem's atomic_open() method shall return NULL after calling this.
*/
-struct file *nameidata_to_filp(struct nameidata *nd)
+int finish_no_open(struct file *file, struct dentry *dentry)
{
- const struct cred *cred = current_cred();
- struct file *filp;
-
- /* Pick up the filp from the open intent */
- filp = nd->intent.open.file;
-
- /* Has the filesystem initialised the file for us? */
- if (filp->f_path.dentry != NULL) {
- nd->intent.open.file = NULL;
- } else {
- struct file *res;
-
- path_get(&nd->path);
- res = do_dentry_open(nd->path.dentry, nd->path.mnt,
- filp, NULL, cred);
- if (!IS_ERR(res)) {
- int error;
-
- nd->intent.open.file = NULL;
- BUG_ON(res != filp);
-
- error = open_check_o_direct(filp);
- if (error) {
- fput(filp);
- filp = ERR_PTR(error);
- }
- } else {
- /* Allow nd->intent.open.file to be recycled */
- filp = res;
- }
- }
- return filp;
+ file->f_path.dentry = dentry;
+ return 1;
}
+EXPORT_SYMBOL(finish_no_open);
-/*
- * dentry_open() will have done dput(dentry) and mntput(mnt) if it returns an
- * error.
- */
-struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags,
+struct file *dentry_open(const struct path *path, int flags,
const struct cred *cred)
{
int error;
@@ -866,18 +775,28 @@ struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags,
validate_creds(cred);
/* We must always pass in a valid mount pointer. */
- BUG_ON(!mnt);
+ BUG_ON(!path->mnt);
error = -ENFILE;
f = get_empty_filp();
- if (f == NULL) {
- dput(dentry);
- mntput(mnt);
+ if (f == NULL)
return ERR_PTR(error);
- }
f->f_flags = flags;
- return __dentry_open(dentry, mnt, f, NULL, cred);
+ f->f_path = *path;
+ path_get(&f->f_path);
+ error = do_dentry_open(f, NULL, cred);
+ if (!error) {
+ error = open_check_o_direct(f);
+ if (error) {
+ fput(f);
+ f = ERR_PTR(error);
+ }
+ } else {
+ put_filp(f);
+ f = ERR_PTR(error);
+ }
+ return f;
}
EXPORT_SYMBOL(dentry_open);
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