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-rw-r--r--fs/namei.c126
1 files changed, 62 insertions, 64 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 0c3974cd3ecd..3c909aebef70 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -505,13 +505,13 @@ struct nameidata {
int total_link_count;
struct saved {
struct path link;
- void *cookie;
+ struct delayed_call done;
const char *name;
- struct inode *inode;
unsigned seq;
} *stack, internal[EMBEDDED_LEVELS];
struct filename *name;
struct nameidata *saved;
+ struct inode *link_inode;
unsigned root_seq;
int dfd;
};
@@ -592,11 +592,8 @@ static void drop_links(struct nameidata *nd)
int i = nd->depth;
while (i--) {
struct saved *last = nd->stack + i;
- struct inode *inode = last->inode;
- if (last->cookie && inode->i_op->put_link) {
- inode->i_op->put_link(inode, last->cookie);
- last->cookie = NULL;
- }
+ do_delayed_call(&last->done);
+ clear_delayed_call(&last->done);
}
}
@@ -842,7 +839,7 @@ static inline void path_to_nameidata(const struct path *path,
}
/*
- * Helper to directly jump to a known parsed path from ->follow_link,
+ * Helper to directly jump to a known parsed path from ->get_link,
* caller must have taken a reference to path beforehand.
*/
void nd_jump_link(struct path *path)
@@ -858,9 +855,7 @@ void nd_jump_link(struct path *path)
static inline void put_link(struct nameidata *nd)
{
struct saved *last = nd->stack + --nd->depth;
- struct inode *inode = last->inode;
- if (last->cookie && inode->i_op->put_link)
- inode->i_op->put_link(inode, last->cookie);
+ do_delayed_call(&last->done);
if (!(nd->flags & LOOKUP_RCU))
path_put(&last->link);
}
@@ -892,7 +887,7 @@ static inline int may_follow_link(struct nameidata *nd)
return 0;
/* Allowed if owner and follower match. */
- inode = nd->stack[0].inode;
+ inode = nd->link_inode;
if (uid_eq(current_cred()->fsuid, inode->i_uid))
return 0;
@@ -983,7 +978,7 @@ const char *get_link(struct nameidata *nd)
{
struct saved *last = nd->stack + nd->depth - 1;
struct dentry *dentry = last->link.dentry;
- struct inode *inode = last->inode;
+ struct inode *inode = nd->link_inode;
int error;
const char *res;
@@ -1004,15 +999,21 @@ const char *get_link(struct nameidata *nd)
nd->last_type = LAST_BIND;
res = inode->i_link;
if (!res) {
+ const char * (*get)(struct dentry *, struct inode *,
+ struct delayed_call *);
+ get = inode->i_op->get_link;
if (nd->flags & LOOKUP_RCU) {
- if (unlikely(unlazy_walk(nd, NULL, 0)))
- return ERR_PTR(-ECHILD);
+ res = get(NULL, inode, &last->done);
+ if (res == ERR_PTR(-ECHILD)) {
+ if (unlikely(unlazy_walk(nd, NULL, 0)))
+ return ERR_PTR(-ECHILD);
+ res = get(dentry, inode, &last->done);
+ }
+ } else {
+ res = get(dentry, inode, &last->done);
}
- res = inode->i_op->follow_link(dentry, &last->cookie);
- if (IS_ERR_OR_NULL(res)) {
- last->cookie = NULL;
+ if (IS_ERR_OR_NULL(res))
return res;
- }
}
if (*res == '/') {
if (nd->flags & LOOKUP_RCU) {
@@ -1691,8 +1692,8 @@ static int pick_link(struct nameidata *nd, struct path *link,
last = nd->stack + nd->depth++;
last->link = *link;
- last->cookie = NULL;
- last->inode = inode;
+ clear_delayed_call(&last->done);
+ nd->link_inode = inode;
last->seq = seq;
return 1;
}
@@ -4495,72 +4496,73 @@ EXPORT_SYMBOL(readlink_copy);
/*
* A helper for ->readlink(). This should be used *ONLY* for symlinks that
- * have ->follow_link() touching nd only in nd_set_link(). Using (or not
- * using) it for any given inode is up to filesystem.
+ * have ->get_link() not calling nd_jump_link(). Using (or not using) it
+ * for any given inode is up to filesystem.
*/
int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)
{
- void *cookie;
+ DEFINE_DELAYED_CALL(done);
struct inode *inode = d_inode(dentry);
const char *link = inode->i_link;
int res;
if (!link) {
- link = inode->i_op->follow_link(dentry, &cookie);
+ link = inode->i_op->get_link(dentry, inode, &done);
if (IS_ERR(link))
return PTR_ERR(link);
}
res = readlink_copy(buffer, buflen, link);
- if (inode->i_op->put_link)
- inode->i_op->put_link(inode, cookie);
+ do_delayed_call(&done);
return res;
}
EXPORT_SYMBOL(generic_readlink);
/* get the link contents into pagecache */
-static char *page_getlink(struct dentry * dentry, struct page **ppage)
+const char *page_get_link(struct dentry *dentry, struct inode *inode,
+ struct delayed_call *callback)
{
char *kaddr;
struct page *page;
- struct address_space *mapping = dentry->d_inode->i_mapping;
- page = read_mapping_page(mapping, 0, NULL);
- if (IS_ERR(page))
- return (char*)page;
- *ppage = page;
- kaddr = kmap(page);
- nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1);
+ struct address_space *mapping = inode->i_mapping;
+
+ if (!dentry) {
+ page = find_get_page(mapping, 0);
+ if (!page)
+ return ERR_PTR(-ECHILD);
+ if (!PageUptodate(page)) {
+ put_page(page);
+ return ERR_PTR(-ECHILD);
+ }
+ } else {
+ page = read_mapping_page(mapping, 0, NULL);
+ if (IS_ERR(page))
+ return (char*)page;
+ }
+ set_delayed_call(callback, page_put_link, page);
+ BUG_ON(mapping_gfp_mask(mapping) & __GFP_HIGHMEM);
+ kaddr = page_address(page);
+ nd_terminate_link(kaddr, inode->i_size, PAGE_SIZE - 1);
return kaddr;
}
-int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)
-{
- struct page *page = NULL;
- int res = readlink_copy(buffer, buflen, page_getlink(dentry, &page));
- if (page) {
- kunmap(page);
- page_cache_release(page);
- }
- return res;
-}
-EXPORT_SYMBOL(page_readlink);
+EXPORT_SYMBOL(page_get_link);
-const char *page_follow_link_light(struct dentry *dentry, void **cookie)
+void page_put_link(void *arg)
{
- struct page *page = NULL;
- char *res = page_getlink(dentry, &page);
- if (!IS_ERR(res))
- *cookie = page;
- return res;
+ put_page(arg);
}
-EXPORT_SYMBOL(page_follow_link_light);
+EXPORT_SYMBOL(page_put_link);
-void page_put_link(struct inode *unused, void *cookie)
+int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)
{
- struct page *page = cookie;
- kunmap(page);
- page_cache_release(page);
+ DEFINE_DELAYED_CALL(done);
+ int res = readlink_copy(buffer, buflen,
+ page_get_link(dentry, d_inode(dentry),
+ &done));
+ do_delayed_call(&done);
+ return res;
}
-EXPORT_SYMBOL(page_put_link);
+EXPORT_SYMBOL(page_readlink);
/*
* The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS
@@ -4571,7 +4573,6 @@ int __page_symlink(struct inode *inode, const char *symname, int len, int nofs)
struct page *page;
void *fsdata;
int err;
- char *kaddr;
unsigned int flags = AOP_FLAG_UNINTERRUPTIBLE;
if (nofs)
flags |= AOP_FLAG_NOFS;
@@ -4582,9 +4583,7 @@ retry:
if (err)
goto fail;
- kaddr = kmap_atomic(page);
- memcpy(kaddr, symname, len-1);
- kunmap_atomic(kaddr);
+ memcpy(page_address(page), symname, len-1);
err = pagecache_write_end(NULL, mapping, 0, len-1, len-1,
page, fsdata);
@@ -4609,7 +4608,6 @@ EXPORT_SYMBOL(page_symlink);
const struct inode_operations page_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
- .put_link = page_put_link,
+ .get_link = page_get_link,
};
EXPORT_SYMBOL(page_symlink_inode_operations);
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-12 10:08:16 +0000