]> www.pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - fs/autofs4/root.c
autofs4: don't make expiring dentry negative
[linux-2.6-omap-h63xx.git] / fs / autofs4 / root.c
index edf5b6bddb528a43bb85e51eb834ecbdb14a7877..9ead2279df4fad5b70306074ab50a2e7d66b8874 100644 (file)
@@ -493,10 +493,10 @@ void autofs4_dentry_release(struct dentry *de)
                struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb);
 
                if (sbi) {
-                       spin_lock(&sbi->rehash_lock);
-                       if (!list_empty(&inf->rehash))
-                               list_del(&inf->rehash);
-                       spin_unlock(&sbi->rehash_lock);
+                       spin_lock(&sbi->lookup_lock);
+                       if (!list_empty(&inf->expiring))
+                               list_del(&inf->expiring);
+                       spin_unlock(&sbi->lookup_lock);
                }
 
                inf->dentry = NULL;
@@ -518,7 +518,7 @@ static struct dentry_operations autofs4_dentry_operations = {
        .d_release      = autofs4_dentry_release,
 };
 
-static struct dentry *autofs4_lookup_unhashed(struct autofs_sb_info *sbi, struct dentry *parent, struct qstr *name)
+static struct dentry *autofs4_lookup_expiring(struct autofs_sb_info *sbi, struct dentry *parent, struct qstr *name)
 {
        unsigned int len = name->len;
        unsigned int hash = name->hash;
@@ -526,14 +526,14 @@ static struct dentry *autofs4_lookup_unhashed(struct autofs_sb_info *sbi, struct
        struct list_head *p, *head;
 
        spin_lock(&dcache_lock);
-       spin_lock(&sbi->rehash_lock);
-       head = &sbi->rehash_list;
+       spin_lock(&sbi->lookup_lock);
+       head = &sbi->expiring_list;
        list_for_each(p, head) {
                struct autofs_info *ino;
                struct dentry *dentry;
                struct qstr *qstr;
 
-               ino = list_entry(p, struct autofs_info, rehash);
+               ino = list_entry(p, struct autofs_info, expiring);
                dentry = ino->dentry;
 
                spin_lock(&dentry->d_lock);
@@ -555,33 +555,16 @@ static struct dentry *autofs4_lookup_unhashed(struct autofs_sb_info *sbi, struct
                        goto next;
 
                if (d_unhashed(dentry)) {
-                       struct inode *inode = dentry->d_inode;
-
-                       ino = autofs4_dentry_ino(dentry);
-                       list_del_init(&ino->rehash);
                        dget(dentry);
-                       /*
-                        * Make the rehashed dentry negative so the VFS
-                        * behaves as it should.
-                        */
-                       if (inode) {
-                               dentry->d_inode = NULL;
-                               list_del_init(&dentry->d_alias);
-                               spin_unlock(&dentry->d_lock);
-                               spin_unlock(&sbi->rehash_lock);
-                               spin_unlock(&dcache_lock);
-                               iput(inode);
-                               return dentry;
-                       }
                        spin_unlock(&dentry->d_lock);
-                       spin_unlock(&sbi->rehash_lock);
+                       spin_unlock(&sbi->lookup_lock);
                        spin_unlock(&dcache_lock);
                        return dentry;
                }
 next:
                spin_unlock(&dentry->d_lock);
        }
-       spin_unlock(&sbi->rehash_lock);
+       spin_unlock(&sbi->lookup_lock);
        spin_unlock(&dcache_lock);
 
        return NULL;
@@ -591,7 +574,7 @@ next:
 static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 {
        struct autofs_sb_info *sbi;
-       struct dentry *unhashed;
+       struct dentry *expiring;
        int oz_mode;
 
        DPRINTK("name = %.*s",
@@ -607,44 +590,44 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s
        DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
                 current->pid, task_pgrp_nr(current), sbi->catatonic, oz_mode);
 
-       unhashed = autofs4_lookup_unhashed(sbi, dentry->d_parent, &dentry->d_name);
-       if (!unhashed) {
-               /*
-                * Mark the dentry incomplete but don't hash it. We do this
-                * to serialize our inode creation operations (symlink and
-                * mkdir) which prevents deadlock during the callback to
-                * the daemon. Subsequent user space lookups for the same
-                * dentry are placed on the wait queue while the daemon
-                * itself is allowed passage unresticted so the create
-                * operation itself can then hash the dentry. Finally,
-                * we check for the hashed dentry and return the newly
-                * hashed dentry.
-                */
-               dentry->d_op = &autofs4_root_dentry_operations;
-
-               dentry->d_fsdata = NULL;
-               d_instantiate(dentry, NULL);
-       } else {
-               struct autofs_info *ino = autofs4_dentry_ino(unhashed);
-               DPRINTK("rehash %p with %p", dentry, unhashed);
+       expiring = autofs4_lookup_expiring(sbi, dentry->d_parent, &dentry->d_name);
+       if (expiring) {
+               struct autofs_info *ino = autofs4_dentry_ino(expiring);
                /*
                 * If we are racing with expire the request might not
                 * be quite complete but the directory has been removed
                 * so it must have been successful, so just wait for it.
-                * We need to ensure the AUTOFS_INF_EXPIRING flag is clear
-                * before continuing as revalidate may fail when calling
-                * try_to_fill_dentry (returning EAGAIN) if we don't.
                 */
                while (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
                        DPRINTK("wait for incomplete expire %p name=%.*s",
-                               unhashed, unhashed->d_name.len,
-                               unhashed->d_name.name);
-                       autofs4_wait(sbi, unhashed, NFY_NONE);
+                               expiring, expiring->d_name.len,
+                               expiring->d_name.name);
+                       autofs4_wait(sbi, expiring, NFY_NONE);
                        DPRINTK("request completed");
                }
-               dentry = unhashed;
+               spin_lock(&sbi->lookup_lock);
+               if (!list_empty(&ino->expiring))
+                       list_del_init(&ino->expiring);
+               spin_unlock(&sbi->lookup_lock);
+               dput(expiring);
        }
 
+       /*
+        * Mark the dentry incomplete but don't hash it. We do this
+        * to serialize our inode creation operations (symlink and
+        * mkdir) which prevents deadlock during the callback to
+        * the daemon. Subsequent user space lookups for the same
+        * dentry are placed on the wait queue while the daemon
+        * itself is allowed passage unresticted so the create
+        * operation itself can then hash the dentry. Finally,
+        * we check for the hashed dentry and return the newly
+        * hashed dentry.
+        */
+       dentry->d_op = &autofs4_root_dentry_operations;
+
+       dentry->d_fsdata = NULL;
+       d_instantiate(dentry, NULL);
+
        if (!oz_mode) {
                spin_lock(&dentry->d_lock);
                dentry->d_flags |= DCACHE_AUTOFS_PENDING;
@@ -668,8 +651,6 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s
                        if (sigismember (sigset, SIGKILL) ||
                            sigismember (sigset, SIGQUIT) ||
                            sigismember (sigset, SIGINT)) {
-                           if (unhashed)
-                               dput(unhashed);
                            return ERR_PTR(-ERESTARTNOINTR);
                        }
                }
@@ -699,15 +680,9 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s
                else
                        dentry = ERR_PTR(-ENOENT);
 
-               if (unhashed)
-                       dput(unhashed);
-
                return dentry;
        }
 
-       if (unhashed)
-               return dentry;
-
        return NULL;
 }
 
@@ -769,9 +744,8 @@ static int autofs4_dir_symlink(struct inode *dir,
  * that the file no longer exists. However, doing that means that the
  * VFS layer can turn the dentry into a negative dentry.  We don't want
  * this, because the unlink is probably the result of an expire.
- * We simply d_drop it and add it to a rehash candidates list in the
- * super block, which allows the dentry lookup to reuse it retaining
- * the flags, such as expire in progress, in case we're racing with expire.
+ * We simply d_drop it and add it to a expiring list in the super block,
+ * which allows the dentry lookup to check for an incomplete expire.
  *
  * If a process is blocked on the dentry waiting for the expire to finish,
  * it will invalidate the dentry and try to mount with a new one.
@@ -801,9 +775,9 @@ static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
        dir->i_mtime = CURRENT_TIME;
 
        spin_lock(&dcache_lock);
-       spin_lock(&sbi->rehash_lock);
-       list_add(&ino->rehash, &sbi->rehash_list);
-       spin_unlock(&sbi->rehash_lock);
+       spin_lock(&sbi->lookup_lock);
+       list_add(&ino->expiring, &sbi->expiring_list);
+       spin_unlock(&sbi->lookup_lock);
        spin_lock(&dentry->d_lock);
        __d_drop(dentry);
        spin_unlock(&dentry->d_lock);
@@ -829,9 +803,9 @@ static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
                spin_unlock(&dcache_lock);
                return -ENOTEMPTY;
        }
-       spin_lock(&sbi->rehash_lock);
-       list_add(&ino->rehash, &sbi->rehash_list);
-       spin_unlock(&sbi->rehash_lock);
+       spin_lock(&sbi->lookup_lock);
+       list_add(&ino->expiring, &sbi->expiring_list);
+       spin_unlock(&sbi->lookup_lock);
        spin_lock(&dentry->d_lock);
        __d_drop(dentry);
        spin_unlock(&dentry->d_lock);