evie/android_kernel_oneplus_msm8998
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f2fs: avoid abnormal behavior on broken symlink

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When f2fs_symlink was triggered and checkpoint was done before syncing its
link path, f2fs can get broken symlink like "xxx -> \0\0\0".
This incurs abnormal path_walk by VFS.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Jaegeuk Kim 2015-04-15 13:49:55 -07:00
parent d0cae97cb6
commit feb7cbb079
1 changed files with 19 additions and 1 deletions
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20
fs/f2fs/namei.c
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@ -14,6 +14,7 @@
#include <linux/sched.h> #include <linux/sched.h>
#include <linux/ctype.h> #include <linux/ctype.h>
#include <linux/dcache.h> #include <linux/dcache.h>
#include <linux/namei.h>
#include "f2fs.h" #include "f2fs.h"
#include "node.h" #include "node.h"
@ -295,6 +296,23 @@ fail:
return err; return err;
} }
static void *f2fs_follow_link(struct dentry *dentry, struct nameidata *nd)
{
struct page *page;
page = page_follow_link_light(dentry, nd);
if (IS_ERR(page))
return page;
/* this is broken symlink case */
if (*nd_get_link(nd) == 0) {
kunmap(page);
page_cache_release(page);
return ERR_PTR(-ENOENT);
}
return page;
}
static int f2fs_symlink(struct inode *dir, struct dentry *dentry, static int f2fs_symlink(struct inode *dir, struct dentry *dentry,
const char *symname) const char *symname)
{ {
@ -790,7 +808,7 @@ const struct inode_operations f2fs_dir_inode_operations = {
const struct inode_operations f2fs_symlink_inode_operations = { const struct inode_operations f2fs_symlink_inode_operations = {
.readlink = generic_readlink, .readlink = generic_readlink,
.follow_link = page_follow_link_light, .follow_link = f2fs_follow_link,
.put_link = page_put_link, .put_link = page_put_link,
.getattr = f2fs_getattr, .getattr = f2fs_getattr,
.setattr = f2fs_setattr, .setattr = f2fs_setattr,