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-rw-r--r--Documentation/filesystems/Locking2
-rw-r--r--Documentation/filesystems/vfs.txt2
-rw-r--r--fs/autofs4/autofs_i.h5
-rw-r--r--fs/autofs4/dev-ioctl.c4
-rw-r--r--fs/autofs4/expire.c25
-rw-r--r--fs/autofs4/root.c61
-rw-r--r--fs/autofs4/waitq.c13
-rw-r--r--fs/dcache.c40
-rw-r--r--fs/mount.h6
-rw-r--r--fs/namei.c13
-rw-r--r--fs/namespace.c29
-rw-r--r--include/linux/dcache.h4
-rw-r--r--include/linux/mount.h2
13 files changed, 131 insertions, 75 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 1b5f15653b1b..4ca3a8d1349d 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -20,7 +20,7 @@ prototypes:
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)((struct dentry *dentry, char *buffer, int buflen);
struct vfsmount *(*d_automount)(struct path *path);
- int (*d_manage)(struct dentry *, bool);
+ int (*d_manage)(const struct path *, bool);
struct dentry *(*d_real)(struct dentry *, const struct inode *,
unsigned int);
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index b5039a00caaf..3893f4d44cd4 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -948,7 +948,7 @@ struct dentry_operations {
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)(struct dentry *, char *, int);
struct vfsmount *(*d_automount)(struct path *);
- int (*d_manage)(struct dentry *, bool);
+ int (*d_manage)(const struct path *, bool);
struct dentry *(*d_real)(struct dentry *, const struct inode *,
unsigned int);
};
diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index a1fba4285277..c885daae68c8 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -145,7 +145,7 @@ void autofs4_free_ino(struct autofs_info *);
/* Expiration */
int is_autofs4_dentry(struct dentry *);
-int autofs4_expire_wait(struct dentry *dentry, int rcu_walk);
+int autofs4_expire_wait(const struct path *path, int rcu_walk);
int autofs4_expire_run(struct super_block *, struct vfsmount *,
struct autofs_sb_info *,
struct autofs_packet_expire __user *);
@@ -217,7 +217,8 @@ static inline int autofs_prepare_pipe(struct file *pipe)
/* Queue management functions */
-int autofs4_wait(struct autofs_sb_info *, struct dentry *, enum autofs_notify);
+int autofs4_wait(struct autofs_sb_info *,
+ const struct path *, enum autofs_notify);
int autofs4_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
void autofs4_catatonic_mode(struct autofs_sb_info *);
diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
index dfc6f49ee597..6f48d670c941 100644
--- a/fs/autofs4/dev-ioctl.c
+++ b/fs/autofs4/dev-ioctl.c
@@ -468,7 +468,7 @@ static int autofs_dev_ioctl_requester(struct file *fp,
ino = autofs4_dentry_ino(path.dentry);
if (ino) {
err = 0;
- autofs4_expire_wait(path.dentry, 0);
+ autofs4_expire_wait(&path, 0);
spin_lock(&sbi->fs_lock);
param->requester.uid =
from_kuid_munged(current_user_ns(), ino->uid);
@@ -575,7 +575,7 @@ static int autofs_dev_ioctl_ismountpoint(struct file *fp,
devid = new_encode_dev(dev);
- err = have_submounts(path.dentry);
+ err = path_has_submounts(&path);
if (follow_down_one(&path))
magic = path.dentry->d_sb->s_magic;
diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index d8e6d421c27f..57725d4a8c59 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -310,26 +310,29 @@ struct dentry *autofs4_expire_direct(struct super_block *sb,
now = jiffies;
timeout = sbi->exp_timeout;
- spin_lock(&sbi->fs_lock);
- ino = autofs4_dentry_ino(root);
- /* No point expiring a pending mount */
- if (ino->flags & AUTOFS_INF_PENDING)
- goto out;
if (!autofs4_direct_busy(mnt, root, timeout, do_now)) {
+ spin_lock(&sbi->fs_lock);
+ ino = autofs4_dentry_ino(root);
+ /* No point expiring a pending mount */
+ if (ino->flags & AUTOFS_INF_PENDING) {
+ spin_unlock(&sbi->fs_lock);
+ goto out;
+ }
ino->flags |= AUTOFS_INF_WANT_EXPIRE;
spin_unlock(&sbi->fs_lock);
synchronize_rcu();
- spin_lock(&sbi->fs_lock);
if (!autofs4_direct_busy(mnt, root, timeout, do_now)) {
+ spin_lock(&sbi->fs_lock);
ino->flags |= AUTOFS_INF_EXPIRING;
init_completion(&ino->expire_complete);
spin_unlock(&sbi->fs_lock);
return root;
}
+ spin_lock(&sbi->fs_lock);
ino->flags &= ~AUTOFS_INF_WANT_EXPIRE;
+ spin_unlock(&sbi->fs_lock);
}
out:
- spin_unlock(&sbi->fs_lock);
dput(root);
return NULL;
@@ -495,8 +498,9 @@ found:
return expired;
}
-int autofs4_expire_wait(struct dentry *dentry, int rcu_walk)
+int autofs4_expire_wait(const struct path *path, int rcu_walk)
{
+ struct dentry *dentry = path->dentry;
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
int status;
@@ -525,7 +529,7 @@ retry:
pr_debug("waiting for expire %p name=%pd\n", dentry, dentry);
- status = autofs4_wait(sbi, dentry, NFY_NONE);
+ status = autofs4_wait(sbi, path, NFY_NONE);
wait_for_completion(&ino->expire_complete);
pr_debug("expire done status=%d\n", status);
@@ -592,11 +596,12 @@ int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
if (dentry) {
struct autofs_info *ino = autofs4_dentry_ino(dentry);
+ const struct path path = { .mnt = mnt, .dentry = dentry };
/* This is synchronous because it makes the daemon a
* little easier
*/
- ret = autofs4_wait(sbi, dentry, NFY_EXPIRE);
+ ret = autofs4_wait(sbi, &path, NFY_EXPIRE);
spin_lock(&sbi->fs_lock);
/* avoid rapid-fire expire attempts if expiry fails */
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index a11f73174877..82e8f6edfb48 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -32,7 +32,7 @@ static int autofs4_dir_open(struct inode *inode, struct file *file);
static struct dentry *autofs4_lookup(struct inode *,
struct dentry *, unsigned int);
static struct vfsmount *autofs4_d_automount(struct path *);
-static int autofs4_d_manage(struct dentry *, bool);
+static int autofs4_d_manage(const struct path *, bool);
static void autofs4_dentry_release(struct dentry *);
const struct file_operations autofs4_root_operations = {
@@ -123,7 +123,7 @@ static int autofs4_dir_open(struct inode *inode, struct file *file)
* it.
*/
spin_lock(&sbi->lookup_lock);
- if (!d_mountpoint(dentry) && simple_empty(dentry)) {
+ if (!path_is_mountpoint(&file->f_path) && simple_empty(dentry)) {
spin_unlock(&sbi->lookup_lock);
return -ENOENT;
}
@@ -269,39 +269,41 @@ next:
return NULL;
}
-static int autofs4_mount_wait(struct dentry *dentry, bool rcu_walk)
+static int autofs4_mount_wait(const struct path *path, bool rcu_walk)
{
- struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
- struct autofs_info *ino = autofs4_dentry_ino(dentry);
+ struct autofs_sb_info *sbi = autofs4_sbi(path->dentry->d_sb);
+ struct autofs_info *ino = autofs4_dentry_ino(path->dentry);
int status = 0;
if (ino->flags & AUTOFS_INF_PENDING) {
if (rcu_walk)
return -ECHILD;
- pr_debug("waiting for mount name=%pd\n", dentry);
- status = autofs4_wait(sbi, dentry, NFY_MOUNT);
+ pr_debug("waiting for mount name=%pd\n", path->dentry);
+ status = autofs4_wait(sbi, path, NFY_MOUNT);
pr_debug("mount wait done status=%d\n", status);
}
ino->last_used = jiffies;
return status;
}
-static int do_expire_wait(struct dentry *dentry, bool rcu_walk)
+static int do_expire_wait(const struct path *path, bool rcu_walk)
{
+ struct dentry *dentry = path->dentry;
struct dentry *expiring;
expiring = autofs4_lookup_expiring(dentry, rcu_walk);
if (IS_ERR(expiring))
return PTR_ERR(expiring);
if (!expiring)
- return autofs4_expire_wait(dentry, rcu_walk);
+ return autofs4_expire_wait(path, rcu_walk);
else {
+ const struct path this = { .mnt = path->mnt, .dentry = 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, just wait for it.
*/
- autofs4_expire_wait(expiring, 0);
+ autofs4_expire_wait(&this, 0);
autofs4_del_expiring(expiring);
dput(expiring);
}
@@ -354,7 +356,7 @@ static struct vfsmount *autofs4_d_automount(struct path *path)
* and the directory was removed, so just go ahead and try
* the mount.
*/
- status = do_expire_wait(dentry, 0);
+ status = do_expire_wait(path, 0);
if (status && status != -EAGAIN)
return NULL;
@@ -362,7 +364,7 @@ static struct vfsmount *autofs4_d_automount(struct path *path)
spin_lock(&sbi->fs_lock);
if (ino->flags & AUTOFS_INF_PENDING) {
spin_unlock(&sbi->fs_lock);
- status = autofs4_mount_wait(dentry, 0);
+ status = autofs4_mount_wait(path, 0);
if (status)
return ERR_PTR(status);
goto done;
@@ -370,28 +372,28 @@ static struct vfsmount *autofs4_d_automount(struct path *path)
/*
* If the dentry is a symlink it's equivalent to a directory
- * having d_mountpoint() true, so there's no need to call back
- * to the daemon.
+ * having path_is_mountpoint() true, so there's no need to call
+ * back to the daemon.
*/
if (d_really_is_positive(dentry) && d_is_symlink(dentry)) {
spin_unlock(&sbi->fs_lock);
goto done;
}
- if (!d_mountpoint(dentry)) {
+ if (!path_is_mountpoint(path)) {
/*
* It's possible that user space hasn't removed directories
* after umounting a rootless multi-mount, although it
- * should. For v5 have_submounts() is sufficient to handle
- * this because the leaves of the directory tree under the
- * mount never trigger mounts themselves (they have an autofs
- * trigger mount mounted on them). But v4 pseudo direct mounts
- * do need the leaves to trigger mounts. In this case we
- * have no choice but to use the list_empty() check and
+ * should. For v5 path_has_submounts() is sufficient to
+ * handle this because the leaves of the directory tree under
+ * the mount never trigger mounts themselves (they have an
+ * autofs trigger mount mounted on them). But v4 pseudo direct
+ * mounts do need the leaves to trigger mounts. In this case
+ * we have no choice but to use the list_empty() check and
* require user space behave.
*/
if (sbi->version > 4) {
- if (have_submounts(dentry)) {
+ if (path_has_submounts(path)) {
spin_unlock(&sbi->fs_lock);
goto done;
}
@@ -403,7 +405,7 @@ static struct vfsmount *autofs4_d_automount(struct path *path)
}
ino->flags |= AUTOFS_INF_PENDING;
spin_unlock(&sbi->fs_lock);
- status = autofs4_mount_wait(dentry, 0);
+ status = autofs4_mount_wait(path, 0);
spin_lock(&sbi->fs_lock);
ino->flags &= ~AUTOFS_INF_PENDING;
if (status) {
@@ -421,8 +423,9 @@ done:
return NULL;
}
-static int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
+static int autofs4_d_manage(const struct path *path, bool rcu_walk)
{
+ struct dentry *dentry = path->dentry;
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
int status;
@@ -431,20 +434,20 @@ static int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
/* The daemon never waits. */
if (autofs4_oz_mode(sbi)) {
- if (!d_mountpoint(dentry))
+ if (!path_is_mountpoint(path))
return -EISDIR;
return 0;
}
/* Wait for pending expires */
- if (do_expire_wait(dentry, rcu_walk) == -ECHILD)
+ if (do_expire_wait(path, rcu_walk) == -ECHILD)
return -ECHILD;
/*
* This dentry may be under construction so wait on mount
* completion.
*/
- status = autofs4_mount_wait(dentry, rcu_walk);
+ status = autofs4_mount_wait(path, rcu_walk);
if (status)
return status;
@@ -460,7 +463,7 @@ static int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
if (ino->flags & AUTOFS_INF_WANT_EXPIRE)
return 0;
- if (d_mountpoint(dentry))
+ if (path_is_mountpoint(path))
return 0;
inode = d_inode_rcu(dentry);
if (inode && S_ISLNK(inode->i_mode))
@@ -487,7 +490,7 @@ static int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
* we can avoid needless calls ->d_automount() and avoid
* an incorrect ELOOP error return.
*/
- if ((!d_mountpoint(dentry) && !simple_empty(dentry)) ||
+ if ((!path_is_mountpoint(path) && !simple_empty(dentry)) ||
(d_really_is_positive(dentry) && d_is_symlink(dentry)))
status = -EISDIR;
}
diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
index e44271dfceb6..1278335ce366 100644
--- a/fs/autofs4/waitq.c
+++ b/fs/autofs4/waitq.c
@@ -250,8 +250,9 @@ autofs4_find_wait(struct autofs_sb_info *sbi, const struct qstr *qstr)
static int validate_request(struct autofs_wait_queue **wait,
struct autofs_sb_info *sbi,
const struct qstr *qstr,
- struct dentry *dentry, enum autofs_notify notify)
+ const struct path *path, enum autofs_notify notify)
{
+ struct dentry *dentry = path->dentry;
struct autofs_wait_queue *wq;
struct autofs_info *ino;
@@ -314,6 +315,7 @@ static int validate_request(struct autofs_wait_queue **wait,
*/
if (notify == NFY_MOUNT) {
struct dentry *new = NULL;
+ struct path this;
int valid = 1;
/*
@@ -333,7 +335,9 @@ static int validate_request(struct autofs_wait_queue **wait,
dentry = new;
}
}
- if (have_submounts(dentry))
+ this.mnt = path->mnt;
+ this.dentry = dentry;
+ if (path_has_submounts(&this))
valid = 0;
if (new)
@@ -345,8 +349,9 @@ static int validate_request(struct autofs_wait_queue **wait,
}
int autofs4_wait(struct autofs_sb_info *sbi,
- struct dentry *dentry, enum autofs_notify notify)
+ const struct path *path, enum autofs_notify notify)
{
+ struct dentry *dentry = path->dentry;
struct autofs_wait_queue *wq;
struct qstr qstr;
char *name;
@@ -405,7 +410,7 @@ int autofs4_wait(struct autofs_sb_info *sbi,
return -EINTR;
}
- ret = validate_request(&wq, sbi, &qstr, dentry, notify);
+ ret = validate_request(&wq, sbi, &qstr, path, notify);
if (ret <= 0) {
if (ret != -EINTR)
mutex_unlock(&sbi->wq_mutex);
diff --git a/fs/dcache.c b/fs/dcache.c
index 5c7cc953ac81..252378359a8f 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1273,38 +1273,44 @@ rename_retry:
goto again;
}
-/*
- * Search for at least 1 mount point in the dentry's subdirs.
- * We descend to the next level whenever the d_subdirs
- * list is non-empty and continue searching.
- */
+struct check_mount {
+ struct vfsmount *mnt;
+ unsigned int mounted;
+};
-static enum d_walk_ret check_mount(void *data, struct dentry *dentry)
+static enum d_walk_ret path_check_mount(void *data, struct dentry *dentry)
{
- int *ret = data;
- if (d_mountpoint(dentry)) {
- *ret = 1;
+ struct check_mount *info = data;
+ struct path path = { .mnt = info->mnt, .dentry = dentry };
+
+ if (likely(!d_mountpoint(dentry)))
+ return D_WALK_CONTINUE;
+ if (__path_is_mountpoint(&path)) {
+ info->mounted = 1;
return D_WALK_QUIT;
}
return D_WALK_CONTINUE;
}
/**
- * have_submounts - check for mounts over a dentry
- * @parent: dentry to check.
+ * path_has_submounts - check for mounts over a dentry in the
+ * current namespace.
+ * @parent: path to check.
*
* Return true if the parent or its subdirectories contain
- * a mount point
+ * a mount point in the current namespace.
*/
-int have_submounts(struct dentry *parent)
+int path_has_submounts(const struct path *parent)
{
- int ret = 0;
+ struct check_mount data = { .mnt = parent->mnt, .mounted = 0 };
- d_walk(parent, &ret, check_mount, NULL);
+ read_seqlock_excl(&mount_lock);
+ d_walk(parent->dentry, &data, path_check_mount, NULL);
+ read_sequnlock_excl(&mount_lock);
- return ret;
+ return data.mounted;
}
-EXPORT_SYMBOL(have_submounts);
+EXPORT_SYMBOL(path_has_submounts);
/*
* Called by mount code to set a mountpoint and check if the mountpoint is
diff --git a/fs/mount.h b/fs/mount.h
index d2e25d7b64b3..2c856fc47ae3 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -94,6 +94,12 @@ extern struct mount *__lookup_mnt_last(struct vfsmount *, struct dentry *);
extern int __legitimize_mnt(struct vfsmount *, unsigned);
extern bool legitimize_mnt(struct vfsmount *, unsigned);
+static inline bool __path_is_mountpoint(const struct path *path)
+{
+ struct mount *m = __lookup_mnt(path->mnt, path->dentry);
+ return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT));
+}
+
extern void __detach_mounts(struct dentry *dentry);
static inline void detach_mounts(struct dentry *dentry)
diff --git a/fs/namei.c b/fs/namei.c
index 1c8f4386b03f..47781b0d909d 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1200,7 +1200,7 @@ static int follow_managed(struct path *path, struct nameidata *nd)
if (managed & DCACHE_MANAGE_TRANSIT) {
BUG_ON(!path->dentry->d_op);
BUG_ON(!path->dentry->d_op->d_manage);
- ret = path->dentry->d_op->d_manage(path->dentry, false);
+ ret = path->dentry->d_op->d_manage(path, false);
if (ret < 0)
break;
}
@@ -1263,10 +1263,10 @@ int follow_down_one(struct path *path)
}
EXPORT_SYMBOL(follow_down_one);
-static inline int managed_dentry_rcu(struct dentry *dentry)
+static inline int managed_dentry_rcu(const struct path *path)
{
- return (dentry->d_flags & DCACHE_MANAGE_TRANSIT) ?
- dentry->d_op->d_manage(dentry, true) : 0;
+ return (path->dentry->d_flags & DCACHE_MANAGE_TRANSIT) ?
+ path->dentry->d_op->d_manage(path, true) : 0;
}
/*
@@ -1282,7 +1282,7 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
* Don't forget we might have a non-mountpoint managed dentry
* that wants to block transit.
*/
- switch (managed_dentry_rcu(path->dentry)) {
+ switch (managed_dentry_rcu(path)) {
case -ECHILD:
default:
return false;
@@ -1392,8 +1392,7 @@ int follow_down(struct path *path)
if (managed & DCACHE_MANAGE_TRANSIT) {
BUG_ON(!path->dentry->d_op);
BUG_ON(!path->dentry->d_op->d_manage);
- ret = path->dentry->d_op->d_manage(
- path->dentry, false);
+ ret = path->dentry->d_op->d_manage(path, false);
if (ret < 0)
return ret == -EISDIR ? 0 : ret;
}
diff --git a/fs/namespace.c b/fs/namespace.c
index 9ad88a45b3e3..f7e28f8ea04d 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1159,6 +1159,35 @@ struct vfsmount *mntget(struct vfsmount *mnt)
}
EXPORT_SYMBOL(mntget);
+/* path_is_mountpoint() - Check if path is a mount in the current
+ * namespace.
+ *
+ * d_mountpoint() can only be used reliably to establish if a dentry is
+ * not mounted in any namespace and that common case is handled inline.
+ * d_mountpoint() isn't aware of the possibility there may be multiple
+ * mounts using a given dentry in a different namespace. This function
+ * checks if the passed in path is a mountpoint rather than the dentry
+ * alone.
+ */
+bool path_is_mountpoint(const struct path *path)
+{
+ unsigned seq;
+ bool res;
+
+ if (!d_mountpoint(path->dentry))
+ return false;
+
+ rcu_read_lock();
+ do {
+ seq = read_seqbegin(&mount_lock);
+ res = __path_is_mountpoint(path);
+ } while (read_seqretry(&mount_lock, seq));
+ rcu_read_unlock();
+
+ return res;
+}
+EXPORT_SYMBOL(path_is_mountpoint);
+
struct vfsmount *mnt_clone_internal(const struct path *path)
{
struct mount *p;
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 5beed7b30561..c965e4469499 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -139,7 +139,7 @@ struct dentry_operations {
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)(struct dentry *, char *, int);
struct vfsmount *(*d_automount)(struct path *);
- int (*d_manage)(struct dentry *, bool);
+ int (*d_manage)(const struct path *, bool);
struct dentry *(*d_real)(struct dentry *, const struct inode *,
unsigned int);
} ____cacheline_aligned;
@@ -254,7 +254,7 @@ extern struct dentry *d_find_alias(struct inode *);
extern void d_prune_aliases(struct inode *);
/* test whether we have any submounts in a subdir tree */
-extern int have_submounts(struct dentry *);
+extern int path_has_submounts(const struct path *);
/*
* This adds the entry to the hash queues.
diff --git a/include/linux/mount.h b/include/linux/mount.h
index cf2b5784b649..c6f55158d5e5 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -98,4 +98,6 @@ extern dev_t name_to_dev_t(const char *name);
extern unsigned int sysctl_mount_max;
+extern bool path_is_mountpoint(const struct path *path);
+
#endif /* _LINUX_MOUNT_H */
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.