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path: root/fs/autofs4/root.c
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Diffstat (limited to 'fs/autofs4/root.c')
-rw-r--r--fs/autofs4/root.c169
1 files changed, 139 insertions, 30 deletions
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index 53dabe8d5b8..dbb70d5a488 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -473,6 +473,8 @@ void autofs4_dentry_release(struct dentry *de)
if (sbi) {
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);
@@ -497,6 +499,58 @@ static struct dentry_operations autofs4_dentry_operations = {
.d_release = autofs4_dentry_release,
};
+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;
+ const unsigned char *str = name->name;
+ struct list_head *p, *head;
+
+ spin_lock(&dcache_lock);
+ 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, 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;
@@ -553,7 +607,8 @@ next:
static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
{
struct autofs_sb_info *sbi;
- struct dentry *expiring;
+ struct autofs_info *ino;
+ struct dentry *expiring, *unhashed;
int oz_mode;
DPRINTK("name = %.*s",
@@ -571,12 +626,12 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s
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.
*/
+ 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,
@@ -591,21 +646,41 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s
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;
+ 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
+ * 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;
+
+ /*
+ * 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.
+ */
+ 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);
- dentry->d_fsdata = NULL;
- d_instantiate(dentry, NULL);
+ d_instantiate(dentry, NULL);
+ }
if (!oz_mode) {
spin_lock(&dentry->d_lock);
@@ -630,12 +705,16 @@ 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);
}
}
- 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);
+ }
}
/*
@@ -659,9 +738,15 @@ 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 unhashed;
+
return NULL;
}
@@ -682,20 +767,30 @@ static int autofs4_dir_symlink(struct inode *dir,
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;
+ 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)
@@ -711,6 +806,8 @@ static int autofs4_dir_symlink(struct inode *dir,
atomic_inc(&p_ino->count);
ino->inode = inode;
+ ino->size = strlen(symname);
+ ino->u.symlink = cp;
dir->i_mtime = CURRENT_TIME;
return 0;
@@ -755,7 +852,8 @@ static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
spin_lock(&dcache_lock);
spin_lock(&sbi->lookup_lock);
- list_add(&ino->expiring, &sbi->expiring_list);
+ 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);
@@ -783,7 +881,8 @@ static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
return -ENOTEMPTY;
}
spin_lock(&sbi->lookup_lock);
- list_add(&ino->expiring, &sbi->expiring_list);
+ 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);
@@ -819,10 +918,20 @@ static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
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)
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-11-23 07:38:16 +0000