Merge tag 'sound-3.17-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai...

[pandora-kernel.git] / fs / namei.c

diff --git a/fs/namei.c b/fs/namei.c
index a996bb4..a7b05bf 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -34,6 +34,7 @@
 #include <linux/device_cgroup.h>
 #include <linux/fs_struct.h>
 #include <linux/posix_acl.h>
+#include <linux/hash.h>
 #include <asm/uaccess.h>
 
 #include "internal.h"
@@ -643,24 +644,22 @@ static int complete_walk(struct nameidata *nd)
 
 static __always_inline void set_root(struct nameidata *nd)
 {
-       if (!nd->root.mnt)
-               get_fs_root(current->fs, &nd->root);
+       get_fs_root(current->fs, &nd->root);
 }
 
 static int link_path_walk(const char *, struct nameidata *);
 
-static __always_inline void set_root_rcu(struct nameidata *nd)
+static __always_inline unsigned set_root_rcu(struct nameidata *nd)
 {
-       if (!nd->root.mnt) {
-               struct fs_struct *fs = current->fs;
-               unsigned seq;
+       struct fs_struct *fs = current->fs;
+       unsigned seq, res;
 
-               do {
-                       seq = read_seqcount_begin(&fs->seq);
-                       nd->root = fs->root;
-                       nd->seq = __read_seqcount_begin(&nd->root.dentry->d_seq);
-               } while (read_seqcount_retry(&fs->seq, seq));
-       }
+       do {
+               seq = read_seqcount_begin(&fs->seq);
+               nd->root = fs->root;
+               res = __read_seqcount_begin(&nd->root.dentry->d_seq);
+       } while (read_seqcount_retry(&fs->seq, seq));
+       return res;
 }
 
 static void path_put_conditional(struct path *path, struct nameidata *nd)
@@ -860,7 +859,8 @@ follow_link(struct path *link, struct nameidata *nd, void **p)
                        return PTR_ERR(s);
                }
                if (*s == '/') {
-                       set_root(nd);
+                       if (!nd->root.mnt)
+                               set_root(nd);
                        path_put(&nd->path);
                        nd->path = nd->root;
                        path_get(&nd->root);
@@ -1137,13 +1137,15 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
                 */
                *inode = path->dentry->d_inode;
        }
-       return read_seqretry(&mount_lock, nd->m_seq) &&
+       return !read_seqretry(&mount_lock, nd->m_seq) &&
                !(path->dentry->d_flags & DCACHE_NEED_AUTOMOUNT);
 }
 
 static int follow_dotdot_rcu(struct nameidata *nd)
 {
-       set_root_rcu(nd);
+       struct inode *inode = nd->inode;
+       if (!nd->root.mnt)
+               set_root_rcu(nd);
 
        while (1) {
                if (nd->path.dentry == nd->root.dentry &&
@@ -1155,6 +1157,7 @@ static int follow_dotdot_rcu(struct nameidata *nd)
                        struct dentry *parent = old->d_parent;
                        unsigned seq;
 
+                       inode = parent->d_inode;
                        seq = read_seqcount_begin(&parent->d_seq);
                        if (read_seqcount_retry(&old->d_seq, nd->seq))
                                goto failed;
@@ -1164,6 +1167,7 @@ static int follow_dotdot_rcu(struct nameidata *nd)
                }
                if (!follow_up_rcu(&nd->path))
                        break;
+               inode = nd->path.dentry->d_inode;
                nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
        }
        while (d_mountpoint(nd->path.dentry)) {
@@ -1173,11 +1177,12 @@ static int follow_dotdot_rcu(struct nameidata *nd)
                        break;
                nd->path.mnt = &mounted->mnt;
                nd->path.dentry = mounted->mnt.mnt_root;
+               inode = nd->path.dentry->d_inode;
                nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
-               if (!read_seqretry(&mount_lock, nd->m_seq))
+               if (read_seqretry(&mount_lock, nd->m_seq))
                        goto failed;
        }
-       nd->inode = nd->path.dentry->d_inode;
+       nd->inode = inode;
        return 0;
 
 failed:
@@ -1256,7 +1261,8 @@ static void follow_mount(struct path *path)
 
 static void follow_dotdot(struct nameidata *nd)
 {
-       set_root(nd);
+       if (!nd->root.mnt)
+               set_root(nd);
 
        while(1) {
                struct dentry *old = nd->path.dentry;
@@ -1634,8 +1640,7 @@ static inline int nested_symlink(struct path *path, struct nameidata *nd)
 
 static inline unsigned int fold_hash(unsigned long hash)
 {
-       hash += hash >> (8*sizeof(int));
-       return hash;
+       return hash_64(hash, 32);
 }
 
 #else  /* 32-bit case */
@@ -1669,9 +1674,9 @@ EXPORT_SYMBOL(full_name_hash);
 
 /*
  * Calculate the length and hash of the path component, and
- * return the length of the component;
+ * return the "hash_len" as the result.
  */
-static inline unsigned long hash_name(const char *name, unsigned int *hashp)
+static inline u64 hash_name(const char *name)
 {
        unsigned long a, b, adata, bdata, mask, hash, len;
        const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
@@ -1691,9 +1696,8 @@ static inline unsigned long hash_name(const char *name, unsigned int *hashp)
        mask = create_zero_mask(adata | bdata);
 
        hash += a & zero_bytemask(mask);
-       *hashp = fold_hash(hash);
-
-       return len + find_zero(mask);
+       len += find_zero(mask);
+       return hashlen_create(fold_hash(hash), len);
 }
 
 #else
@@ -1711,7 +1715,7 @@ EXPORT_SYMBOL(full_name_hash);
  * We know there's a real path component here of at least
  * one character.
  */
-static inline unsigned long hash_name(const char *name, unsigned int *hashp)
+static inline u64 hash_name(const char *name)
 {
        unsigned long hash = init_name_hash();
        unsigned long len = 0, c;
@@ -1722,8 +1726,7 @@ static inline unsigned long hash_name(const char *name, unsigned int *hashp)
                hash = partial_name_hash(c, hash);
                c = (unsigned char)name[len];
        } while (c && c != '/');
-       *hashp = end_name_hash(hash);
-       return len;
+       return hashlen_create(end_name_hash(hash), len);
 }
 
 #endif
@@ -1748,20 +1751,17 @@ static int link_path_walk(const char *name, struct nameidata *nd)
 
        /* At this point we know we have a real path component. */
        for(;;) {
-               struct qstr this;
-               long len;
+               u64 hash_len;
                int type;
 
                err = may_lookup(nd);
                if (err)
                        break;
 
-               len = hash_name(name, &this.hash);
-               this.name = name;
-               this.len = len;
+               hash_len = hash_name(name);
 
                type = LAST_NORM;
-               if (name[0] == '.') switch (len) {
+               if (name[0] == '.') switch (hashlen_len(hash_len)) {
                        case 2:
                                if (name[1] == '.') {
                                        type = LAST_DOTDOT;
@@ -1775,29 +1775,32 @@ static int link_path_walk(const char *name, struct nameidata *nd)
                        struct dentry *parent = nd->path.dentry;
                        nd->flags &= ~LOOKUP_JUMPED;
                        if (unlikely(parent->d_flags & DCACHE_OP_HASH)) {
+                               struct qstr this = { { .hash_len = hash_len }, .name = name };
                                err = parent->d_op->d_hash(parent, &this);
                                if (err < 0)
                                        break;
+                               hash_len = this.hash_len;
+                               name = this.name;
                        }
                }
 
-               nd->last = this;
+               nd->last.hash_len = hash_len;
+               nd->last.name = name;
                nd->last_type = type;
 
-               if (!name[len])
+               name += hashlen_len(hash_len);
+               if (!*name)
                        return 0;
                /*
                 * If it wasn't NUL, we know it was '/'. Skip that
                 * slash, and continue until no more slashes.
                 */
                do {
-                       len++;
-               } while (unlikely(name[len] == '/'));
-               if (!name[len])
+                       name++;
+               } while (unlikely(*name == '/'));
+               if (!*name)
                        return 0;
 
-               name += len;
-
                err = walk_component(nd, &next, LOOKUP_FOLLOW);
                if (err < 0)
                        return err;
@@ -1852,7 +1855,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
        if (*name=='/') {
                if (flags & LOOKUP_RCU) {
                        rcu_read_lock();
-                       set_root_rcu(nd);
+                       nd->seq = set_root_rcu(nd);
                } else {
                        set_root(nd);
                        path_get(&nd->root);
@@ -1903,7 +1906,14 @@ static int path_init(int dfd, const char *name, unsigned int flags,
        }
 
        nd->inode = nd->path.dentry->d_inode;
-       return 0;
+       if (!(flags & LOOKUP_RCU))
+               return 0;
+       if (likely(!read_seqcount_retry(&nd->path.dentry->d_seq, nd->seq)))
+               return 0;
+       if (!(nd->flags & LOOKUP_ROOT))
+               nd->root.mnt = NULL;
+       rcu_read_unlock();
+       return -ECHILD;
 }
 
 static inline int lookup_last(struct nameidata *nd, struct path *path)