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Make sure that highmem pages are not added to symlink page cache

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inode_nohighmem() is sufficient to make sure that page_get_link()
won't try to allocate a highmem page.  Moreover, it is sufficient
to make sure that page_symlink/__page_symlink won't do the same
thing.  However, any filesystem that manually preseeds the symlink's
page cache upon symlink(2) needs to make sure that the page it
inserts there won't be a highmem one.

Fortunately, only nfs and shmem have run afoul of that...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
2016-01-14 17:52:59 -05:00
parent 60b7eca1dc
commit e8ecde25f5
3 changed files with 8 additions and 5 deletions
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5
fs/nfs/dir.c
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@@ -1894,15 +1894,14 @@ int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
attr.ia_mode = S_IFLNK | S_IRWXUGO;
attr.ia_valid = ATTR_MODE;
page = alloc_page(GFP_HIGHUSER);
page = alloc_page(GFP_USER);
if (!page)
return -ENOMEM;
kaddr = kmap_atomic(page);
kaddr = page_address(page);
memcpy(kaddr, symname, pathlen);
if (pathlen < PAGE_SIZE)
memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen);
kunmap_atomic(kaddr);
trace_nfs_symlink_enter(dir, dentry);
error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr);