.readdir = autofs4_dir_readdir,
};
-struct inode_operations autofs4_indirect_root_inode_operations = {
+const struct inode_operations autofs4_indirect_root_inode_operations = {
.lookup = autofs4_lookup,
.unlink = autofs4_dir_unlink,
.symlink = autofs4_dir_symlink,
.rmdir = autofs4_dir_rmdir,
};
-struct inode_operations autofs4_direct_root_inode_operations = {
+const struct inode_operations autofs4_direct_root_inode_operations = {
.lookup = autofs4_lookup,
.unlink = autofs4_dir_unlink,
.mkdir = autofs4_dir_mkdir,
.follow_link = autofs4_follow_link,
};
-struct inode_operations autofs4_dir_inode_operations = {
+const struct inode_operations autofs4_dir_inode_operations = {
.lookup = autofs4_lookup,
.unlink = autofs4_dir_unlink,
.symlink = autofs4_dir_symlink,
*/
status = d_invalidate(dentry);
if (status != -EBUSY)
- return -ENOENT;
+ return -EAGAIN;
}
DPRINTK("dentry=%p %.*s ino=%p",
*/
status = try_to_fill_dentry(dentry, flags);
if (status == 0)
- return 1;
+ return 1;
+
+ /*
+ * A status of EAGAIN here means that the dentry has gone
+ * away while waiting for an expire to complete. If we are
+ * racing with expire lookup will wait for it so this must
+ * be a revalidate and we need to send it to lookup.
+ */
+ if (status == -EAGAIN)
+ return 0;
return status;
}
de->d_fsdata = NULL;
if (inf) {
+ struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb);
+
inf->dentry = NULL;
inf->inode = NULL;
+ if (sbi) {
+ spin_lock(&sbi->rehash_lock);
+ if (!list_empty(&inf->rehash))
+ list_del(&inf->rehash);
+ spin_unlock(&sbi->rehash_lock);
+ }
+
autofs4_free_ino(inf);
}
}
.d_release = autofs4_dentry_release,
};
+static struct dentry *autofs4_lookup_unhashed(struct autofs_sb_info *sbi, struct dentry *parent, struct qstr *name)
+{
+ unsigned int len = name->len;
+ unsigned int hash = name->hash;
+ const unsigned char *str = name->name;
+ struct list_head *p, *head;
+
+ spin_lock(&dcache_lock);
+ spin_lock(&sbi->rehash_lock);
+ head = &sbi->rehash_list;
+ list_for_each(p, head) {
+ struct autofs_info *ino;
+ struct dentry *dentry;
+ struct qstr *qstr;
+
+ ino = list_entry(p, struct autofs_info, rehash);
+ dentry = ino->dentry;
+
+ spin_lock(&dentry->d_lock);
+
+ /* Bad luck, we've already been dentry_iput */
+ if (!dentry->d_inode)
+ goto next;
+
+ qstr = &dentry->d_name;
+
+ if (dentry->d_name.hash != hash)
+ goto next;
+ if (dentry->d_parent != parent)
+ goto next;
+
+ if (qstr->len != len)
+ goto next;
+ if (memcmp(qstr->name, str, len))
+ goto next;
+
+ if (d_unhashed(dentry)) {
+ struct autofs_info *ino = autofs4_dentry_ino(dentry);
+ struct inode *inode = dentry->d_inode;
+
+ 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(&dcache_lock);
+ return dentry;
+ }
+next:
+ spin_unlock(&dentry->d_lock);
+ }
+ spin_unlock(&sbi->rehash_lock);
+ spin_unlock(&dcache_lock);
+
+ return NULL;
+}
+
/* Lookups in the root directory */
static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
{
struct autofs_sb_info *sbi;
+ struct dentry *unhashed;
int oz_mode;
DPRINTK("name = %.*s",
DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
current->pid, process_group(current), sbi->catatonic, oz_mode);
- /*
- * Mark the dentry incomplete, but add it. This is needed so
- * that the VFS layer knows about the dentry, and we can count
- * on catching any lookups through the revalidate.
- *
- * Let all the hard work be done by the revalidate function that
- * needs to be able to do this anyway..
- *
- * We need to do this before we release the directory semaphore.
- */
- dentry->d_op = &autofs4_root_dentry_operations;
+ unhashed = autofs4_lookup_unhashed(sbi, dentry->d_parent, &dentry->d_name);
+ if (!unhashed) {
+ /*
+ * Mark the dentry incomplete, but add it. This is needed so
+ * that the VFS layer knows about the dentry, and we can count
+ * on catching any lookups through the revalidate.
+ *
+ * Let all the hard work be done by the revalidate function that
+ * needs to be able to do this anyway..
+ *
+ * We need to do this before we release the directory semaphore.
+ */
+ dentry->d_op = &autofs4_root_dentry_operations;
+
+ dentry->d_fsdata = NULL;
+ d_add(dentry, NULL);
+ } else {
+ struct autofs_info *ino = autofs4_dentry_ino(unhashed);
+ DPRINTK("rehash %p with %p", dentry, unhashed);
+ /*
+ * 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.
+ */
+ if (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);
+ DPRINTK("request completed");
+ }
+ d_rehash(unhashed);
+ dentry = unhashed;
+ }
if (!oz_mode) {
spin_lock(&dentry->d_lock);
dentry->d_flags |= DCACHE_AUTOFS_PENDING;
spin_unlock(&dentry->d_lock);
}
- dentry->d_fsdata = NULL;
- d_add(dentry, NULL);
if (dentry->d_op && dentry->d_op->d_revalidate) {
mutex_unlock(&dir->i_mutex);
if (sigismember (sigset, SIGKILL) ||
sigismember (sigset, SIGQUIT) ||
sigismember (sigset, SIGINT)) {
+ if (unhashed)
+ dput(unhashed);
return ERR_PTR(-ERESTARTNOINTR);
}
}
/*
* If this dentry is unhashed, then we shouldn't honour this
- * lookup even if the dentry is positive. Returning ENOENT here
- * doesn't do the right thing for all system calls, but it should
- * be OK for the operations we permit from an autofs.
+ * lookup. Returning ENOENT here doesn't do the right thing
+ * for all system calls, but it should be OK for the operations
+ * we permit from an autofs.
*/
- if (dentry->d_inode && d_unhashed(dentry))
- return ERR_PTR(-ENOENT);
+ if (dentry->d_inode && d_unhashed(dentry)) {
+ /*
+ * A user space application can (and has done in the past)
+ * remove and re-create this directory during the callback.
+ * This can leave us with an unhashed dentry, but a
+ * successful mount! So we need to perform another
+ * cached lookup in case the dentry now exists.
+ */
+ struct dentry *parent = dentry->d_parent;
+ struct dentry *new = d_lookup(parent, &dentry->d_name);
+ if (new != NULL)
+ dentry = new;
+ else
+ dentry = ERR_PTR(-ENOENT);
+
+ if (unhashed)
+ dput(unhashed);
+
+ return dentry;
+ }
+
+ if (unhashed)
+ return dentry;
return NULL;
}
* Normal filesystems would do a "d_delete()" to tell the VFS dcache
* 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 since the unlink is probably the result of an expire.
- * We simply d_drop it, which allows the dentry lookup to remount it
- * if necessary.
+ * 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.
*
* 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.
dir->i_mtime = CURRENT_TIME;
- d_drop(dentry);
+ spin_lock(&dcache_lock);
+ spin_lock(&sbi->rehash_lock);
+ list_add(&ino->rehash, &sbi->rehash_list);
+ spin_unlock(&sbi->rehash_lock);
+ spin_lock(&dentry->d_lock);
+ __d_drop(dentry);
+ spin_unlock(&dentry->d_lock);
+ spin_unlock(&dcache_lock);
return 0;
}
struct autofs_info *ino = autofs4_dentry_ino(dentry);
struct autofs_info *p_ino;
+ DPRINTK("dentry %p, removing %.*s",
+ dentry, dentry->d_name.len, dentry->d_name.name);
+
if (!autofs4_oz_mode(sbi))
return -EACCES;
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(&dentry->d_lock);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
git.samba.org / sfrench / cifs-2.6.git / blobdiff