static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
static void *autofs4_follow_link(struct dentry *, struct nameidata *);
+#define TRIGGER_FLAGS (LOOKUP_CONTINUE | LOOKUP_DIRECTORY)
+#define TRIGGER_INTENTS (LOOKUP_OPEN | LOOKUP_CREATE)
+
const struct file_operations autofs4_root_operations = {
.open = dcache_dir_open,
.release = dcache_dir_close,
{
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
- struct dentry *new;
int status;
/* Block on any pending expiry here; invalidate the dentry
return status;
}
/* Trigger mount for path component or follow link */
- } else if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) ||
+ } else if (flags & (TRIGGER_FLAGS | TRIGGER_INTENTS) ||
current->link_count) {
DPRINTK("waiting for mount name=%.*s",
dentry->d_name.len, dentry->d_name.name);
dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
spin_unlock(&dentry->d_lock);
- /*
- * The dentry that is passed in from lookup may not be the one
- * we end up using, as mkdir can create a new one. If this
- * happens, and another process tries the lookup at the same time,
- * it will set the PENDING flag on this new dentry, but add itself
- * to our waitq. Then, if after the lookup succeeds, the first
- * process that requested the mount performs another lookup of the
- * same directory, it will show up as still pending! So, we need
- * to redo the lookup here and clear pending on that dentry.
- */
- if (d_unhashed(dentry)) {
- new = d_lookup(dentry->d_parent, &dentry->d_name);
- if (new) {
- spin_lock(&new->d_lock);
- new->d_flags &= ~DCACHE_AUTOFS_PENDING;
- spin_unlock(&new->d_lock);
- dput(new);
- }
- }
-
return 0;
}
nd->flags);
/* If it's our master or we shouldn't trigger a mount we're done */
- lookup_type = nd->flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY);
+ lookup_type = nd->flags & (TRIGGER_FLAGS | TRIGGER_INTENTS);
if (oz_mode || !lookup_type)
goto done;
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->active))
+ list_del(&inf->active);
+ if (!list_empty(&inf->expiring))
+ list_del(&inf->expiring);
+ spin_unlock(&sbi->lookup_lock);
}
inf->dentry = NULL;
.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_active(struct autofs_sb_info *sbi, struct dentry *parent, struct qstr *name)
{
unsigned int len = name->len;
unsigned int hash = name->hash;
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->active_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, active);
+ dentry = ino->dentry;
+
+ spin_lock(&dentry->d_lock);
+
+ /* Already gone? */
+ if (atomic_read(&dentry->d_count) == 0)
+ 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)) {
+ dget(dentry);
+ spin_unlock(&dentry->d_lock);
+ spin_unlock(&sbi->lookup_lock);
+ spin_unlock(&dcache_lock);
+ return dentry;
+ }
+next:
+ spin_unlock(&dentry->d_lock);
+ }
+ spin_unlock(&sbi->lookup_lock);
+ spin_unlock(&dcache_lock);
+
+ return NULL;
+}
+
+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;
+ const unsigned char *str = name->name;
+ struct list_head *p, *head;
+
+ spin_lock(&dcache_lock);
+ 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, expiring);
dentry = ino->dentry;
spin_lock(&dentry->d_lock);
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;
static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
{
struct autofs_sb_info *sbi;
- struct dentry *unhashed;
+ struct autofs_info *ino;
+ struct dentry *expiring, *unhashed;
int oz_mode;
DPRINTK("name = %.*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) {
+ expiring = autofs4_lookup_expiring(sbi, dentry->d_parent, &dentry->d_name);
+ if (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.
+ */
+ ino = autofs4_dentry_ino(expiring);
+ while (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
+ DPRINTK("wait for incomplete expire %p name=%.*s",
+ expiring, expiring->d_name.len,
+ expiring->d_name.name);
+ autofs4_wait(sbi, expiring, NFY_NONE);
+ DPRINTK("request completed");
+ }
+ spin_lock(&sbi->lookup_lock);
+ if (!list_empty(&ino->expiring))
+ list_del_init(&ino->expiring);
+ spin_unlock(&sbi->lookup_lock);
+ dput(expiring);
+ }
+
+ unhashed = autofs4_lookup_active(sbi, dentry->d_parent, &dentry->d_name);
+ if (unhashed)
+ dentry = unhashed;
+ else {
/*
* Mark the dentry incomplete but don't hash it. We do this
* to serialize our inode creation operations (symlink and
*/
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);
/*
- * 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.
+ * And we need to ensure that the same dentry is used for
+ * all following lookup calls until it is hashed so that
+ * the dentry flags are persistent throughout the request.
*/
- 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);
- DPRINTK("request completed");
- }
- dentry = unhashed;
+ ino = autofs4_init_ino(NULL, sbi, 0555);
+ if (!ino)
+ return ERR_PTR(-ENOMEM);
+
+ dentry->d_fsdata = ino;
+ ino->dentry = dentry;
+
+ spin_lock(&sbi->lookup_lock);
+ list_add(&ino->active, &sbi->active_list);
+ spin_unlock(&sbi->lookup_lock);
+
+ d_instantiate(dentry, NULL);
}
if (!oz_mode) {
spin_lock(&dentry->d_lock);
dentry->d_flags |= DCACHE_AUTOFS_PENDING;
spin_unlock(&dentry->d_lock);
- }
-
- if (dentry->d_op && dentry->d_op->d_revalidate) {
- mutex_unlock(&dir->i_mutex);
- (dentry->d_op->d_revalidate)(dentry, nd);
- mutex_lock(&dir->i_mutex);
+ if (dentry->d_op && dentry->d_op->d_revalidate) {
+ mutex_unlock(&dir->i_mutex);
+ (dentry->d_op->d_revalidate)(dentry, nd);
+ mutex_lock(&dir->i_mutex);
+ }
}
/*
return ERR_PTR(-ERESTARTNOINTR);
}
}
- spin_lock(&dentry->d_lock);
- dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
- spin_unlock(&dentry->d_lock);
+ if (!oz_mode) {
+ spin_lock(&dentry->d_lock);
+ dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
+ spin_unlock(&dentry->d_lock);
+ }
}
/*
}
if (unhashed)
- return dentry;
+ return unhashed;
return NULL;
}
return -EACCES;
ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
- if (ino == NULL)
- return -ENOSPC;
+ if (!ino)
+ return -ENOMEM;
- ino->size = strlen(symname);
- ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL);
+ spin_lock(&sbi->lookup_lock);
+ if (!list_empty(&ino->active))
+ list_del_init(&ino->active);
+ spin_unlock(&sbi->lookup_lock);
- if (cp == NULL) {
- kfree(ino);
- return -ENOSPC;
+ ino->size = strlen(symname);
+ cp = kmalloc(ino->size + 1, GFP_KERNEL);
+ if (!cp) {
+ if (!dentry->d_fsdata)
+ kfree(ino);
+ return -ENOMEM;
}
strcpy(cp, symname);
inode = autofs4_get_inode(dir->i_sb, ino);
+ if (!inode) {
+ kfree(cp);
+ if (!dentry->d_fsdata)
+ kfree(ino);
+ return -ENOMEM;
+ }
d_add(dentry, inode);
if (dir == dir->i_sb->s_root->d_inode)
atomic_inc(&p_ino->count);
ino->inode = inode;
+ ino->u.symlink = cp;
dir->i_mtime = CURRENT_TIME;
return 0;
* 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.
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);
+ if (list_empty(&ino->expiring))
+ 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);
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);
+ if (list_empty(&ino->expiring))
+ 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);
dentry, dentry->d_name.len, dentry->d_name.name);
ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
- if (ino == NULL)
- return -ENOSPC;
+ if (!ino)
+ return -ENOMEM;
+
+ spin_lock(&sbi->lookup_lock);
+ if (!list_empty(&ino->active))
+ list_del_init(&ino->active);
+ spin_unlock(&sbi->lookup_lock);
inode = autofs4_get_inode(dir->i_sb, ino);
+ if (!inode) {
+ if (!dentry->d_fsdata)
+ kfree(ino);
+ return -ENOMEM;
+ }
d_add(dentry, inode);
if (dir == dir->i_sb->s_root->d_inode)
projects / linux-2.6-omap-h63xx.git / blobdiff