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namei: explicitly pass seq number to unlazy_walk() when dentry != NULL 

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2015-05-05 09:26:05 -04:00
Родитель 3595e2346c
Коммит 6e9918b7b3
1 изменённых файлов: 8 добавлений и 7 удалений
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15
fs/namei.c
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@ -567,13 +567,14 @@ static inline int nd_alloc_stack(struct nameidata *nd)
* unlazy_walk - try to switch to ref-walk mode. * unlazy_walk - try to switch to ref-walk mode.
* @nd: nameidata pathwalk data * @nd: nameidata pathwalk data
* @dentry: child of nd->path.dentry or NULL * @dentry: child of nd->path.dentry or NULL
* @seq: seq number to check dentry against
* Returns: 0 on success, -ECHILD on failure * Returns: 0 on success, -ECHILD on failure
* *
* unlazy_walk attempts to legitimize the current nd->path, nd->root and dentry * unlazy_walk attempts to legitimize the current nd->path, nd->root and dentry
* for ref-walk mode. @dentry must be a path found by a do_lookup call on * for ref-walk mode. @dentry must be a path found by a do_lookup call on
* @nd or NULL. Must be called from rcu-walk context. * @nd or NULL. Must be called from rcu-walk context.
*/ */
static int unlazy_walk(struct nameidata *nd, struct dentry *dentry) static int unlazy_walk(struct nameidata *nd, struct dentry *dentry, unsigned seq)
{ {
struct fs_struct *fs = current->fs; struct fs_struct *fs = current->fs;
struct dentry *parent = nd->path.dentry; struct dentry *parent = nd->path.dentry;
@ -615,7 +616,7 @@ static int unlazy_walk(struct nameidata *nd, struct dentry *dentry)
} else { } else {
if (!lockref_get_not_dead(&dentry->d_lockref)) if (!lockref_get_not_dead(&dentry->d_lockref))
goto out; goto out;
if (read_seqcount_retry(&dentry->d_seq, nd->seq)) if (read_seqcount_retry(&dentry->d_seq, seq))
goto drop_dentry; goto drop_dentry;
} }
@ -671,7 +672,7 @@ static int complete_walk(struct nameidata *nd)
if (nd->flags & LOOKUP_RCU) { if (nd->flags & LOOKUP_RCU) {
if (!(nd->flags & LOOKUP_ROOT)) if (!(nd->flags & LOOKUP_ROOT))
nd->root.mnt = NULL; nd->root.mnt = NULL;
if (unlikely(unlazy_walk(nd, NULL))) if (unlikely(unlazy_walk(nd, NULL, 0)))
return -ECHILD; return -ECHILD;
} }
@ -1451,7 +1452,7 @@ static int lookup_fast(struct nameidata *nd,
if (likely(__follow_mount_rcu(nd, path, inode))) if (likely(__follow_mount_rcu(nd, path, inode)))
return 0; return 0;
unlazy: unlazy:
if (unlazy_walk(nd, dentry)) if (unlazy_walk(nd, dentry, nd->seq))
return -ECHILD; return -ECHILD;
} else { } else {
dentry = __d_lookup(parent, &nd->last); dentry = __d_lookup(parent, &nd->last);
@ -1511,7 +1512,7 @@ static inline int may_lookup(struct nameidata *nd)
int err = inode_permission(nd->inode, MAY_EXEC|MAY_NOT_BLOCK); int err = inode_permission(nd->inode, MAY_EXEC|MAY_NOT_BLOCK);
if (err != -ECHILD) if (err != -ECHILD)
return err; return err;
if (unlazy_walk(nd, NULL)) if (unlazy_walk(nd, NULL, 0))
return -ECHILD; return -ECHILD;
} }
return inode_permission(nd->inode, MAY_EXEC); return inode_permission(nd->inode, MAY_EXEC);
@ -1552,7 +1553,7 @@ static int pick_link(struct nameidata *nd, struct path *link)
} }
if (nd->flags & LOOKUP_RCU) { if (nd->flags & LOOKUP_RCU) {
if (unlikely(nd->path.mnt != link->mnt || if (unlikely(nd->path.mnt != link->mnt ||
unlazy_walk(nd, link->dentry))) { unlazy_walk(nd, link->dentry, nd->seq))) {
return -ECHILD; return -ECHILD;
} }
} }
@ -2297,7 +2298,7 @@ mountpoint_last(struct nameidata *nd, struct path *path)
/* If we're in rcuwalk, drop out of it to handle last component */ /* If we're in rcuwalk, drop out of it to handle last component */
if (nd->flags & LOOKUP_RCU) { if (nd->flags & LOOKUP_RCU) {
if (unlazy_walk(nd, NULL)) if (unlazy_walk(nd, NULL, 0))
return -ECHILD; return -ECHILD;
} }