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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Browse source 
Pull vfs pile 2 (of many) from Al Viro:
 "Mostly Miklos' series this time"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  constify dcache.c inlined helpers where possible
  fuse: drop dentry on failed revalidate
  fuse: clean up return in fuse_dentry_revalidate()
  fuse: use d_materialise_unique()
  sysfs: use check_submounts_and_drop()
  nfs: use check_submounts_and_drop()
  gfs2: use check_submounts_and_drop()
  afs: use check_submounts_and_drop()
  vfs: check unlinked ancestors before mount
  vfs: check submounts and drop atomically
  vfs: add d_walk()
  vfs: restructure d_genocide()
This commit is contained in:
Linus Torvalds 2013-09-07 14:36:57 -07:00
commit dc0755cdb1
9 changed files with 326 additions and 261 deletions
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10
fs/afs/dir.c
View file

@ -685,16 +685,12 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags)
spin_unlock(&dentry->d_lock);
out_bad:
if (dentry->d_inode) {
/* don't unhash if we have submounts */
if (have_submounts(dentry))
goto out_skip;
}
/* don't unhash if we have submounts */
if (check_submounts_and_drop(dentry) != 0)
goto out_skip;
_debug("dropping dentry %s/%s",
parent->d_name.name, dentry->d_name.name);
shrink_dcache_parent(dentry);
d_drop(dentry);
dput(parent);
key_put(key);

417
fs/dcache.c
View file

@ -1031,34 +1031,56 @@ static struct dentry *try_to_ascend(struct dentry *old, int locked, unsigned seq
return new;
}
/*
* 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.
*/
/**
* have_submounts - check for mounts over a dentry
* @parent: dentry to check.
*
* Return true if the parent or its subdirectories contain
* a mount point
* enum d_walk_ret - action to talke during tree walk
* @D_WALK_CONTINUE: contrinue walk
* @D_WALK_QUIT: quit walk
* @D_WALK_NORETRY: quit when retry is needed
* @D_WALK_SKIP: skip this dentry and its children
*/
int have_submounts(struct dentry *parent)
enum d_walk_ret {
D_WALK_CONTINUE,
D_WALK_QUIT,
D_WALK_NORETRY,
D_WALK_SKIP,
};
/**
* d_walk - walk the dentry tree
* @parent: start of walk
* @data: data passed to @enter() and @finish()
* @enter: callback when first entering the dentry
* @finish: callback when successfully finished the walk
*
* The @enter() and @finish() callbacks are called with d_lock held.
*/
static void d_walk(struct dentry *parent, void *data,
enum d_walk_ret (*enter)(void *, struct dentry *),
void (*finish)(void *))
{
struct dentry *this_parent;
struct list_head *next;
unsigned seq;
int locked = 0;
enum d_walk_ret ret;
bool retry = true;
seq = read_seqbegin(&rename_lock);
again:
this_parent = parent;
if (d_mountpoint(parent))
goto positive;
spin_lock(&this_parent->d_lock);
ret = enter(data, this_parent);
switch (ret) {
case D_WALK_CONTINUE:
break;
case D_WALK_QUIT:
case D_WALK_SKIP:
goto out_unlock;
case D_WALK_NORETRY:
retry = false;
break;
}
repeat:
next = this_parent->d_subdirs.next;
resume:
@ -1068,12 +1090,22 @@ int have_submounts(struct dentry *parent)
next = tmp->next;
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
/* Have we found a mount point ? */
if (d_mountpoint(dentry)) {
ret = enter(data, dentry);
switch (ret) {
case D_WALK_CONTINUE:
break;
case D_WALK_QUIT:
spin_unlock(&dentry->d_lock);
spin_unlock(&this_parent->d_lock);
goto positive;
goto out_unlock;
case D_WALK_NORETRY:
retry = false;
break;
case D_WALK_SKIP:
spin_unlock(&dentry->d_lock);
continue;
}
if (!list_empty(&dentry->d_subdirs)) {
spin_unlock(&this_parent->d_lock);
spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_);
@ -1094,28 +1126,96 @@ int have_submounts(struct dentry *parent)
next = child->d_u.d_child.next;
goto resume;
}
if (!locked && read_seqretry(&rename_lock, seq)) {
spin_unlock(&this_parent->d_lock);
goto rename_retry;
}
if (finish)
finish(data);
out_unlock:
spin_unlock(&this_parent->d_lock);
if (!locked && read_seqretry(&rename_lock, seq))
goto rename_retry;
if (locked)
write_sequnlock(&rename_lock);
return 0; /* No mount points found in tree */
positive:
if (!locked && read_seqretry(&rename_lock, seq))
goto rename_retry;
if (locked)
write_sequnlock(&rename_lock);
return 1;
return;
rename_retry:
if (!retry)
return;
if (locked)
goto again;
locked = 1;
write_seqlock(&rename_lock);
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.
*/
/**
* have_submounts - check for mounts over a dentry
* @parent: dentry to check.
*
* Return true if the parent or its subdirectories contain
* a mount point
*/
static enum d_walk_ret check_mount(void *data, struct dentry *dentry)
{
int *ret = data;
if (d_mountpoint(dentry)) {
*ret = 1;
return D_WALK_QUIT;
}
return D_WALK_CONTINUE;
}
int have_submounts(struct dentry *parent)
{
int ret = 0;
d_walk(parent, &ret, check_mount, NULL);
return ret;
}
EXPORT_SYMBOL(have_submounts);
/*
* Called by mount code to set a mountpoint and check if the mountpoint is
* reachable (e.g. NFS can unhash a directory dentry and then the complete
* subtree can become unreachable).
*
* Only one of check_submounts_and_drop() and d_set_mounted() must succeed. For
* this reason take rename_lock and d_lock on dentry and ancestors.
*/
int d_set_mounted(struct dentry *dentry)
{
struct dentry *p;
int ret = -ENOENT;
write_seqlock(&rename_lock);
for (p = dentry->d_parent; !IS_ROOT(p); p = p->d_parent) {
/* Need exclusion wrt. check_submounts_and_drop() */
spin_lock(&p->d_lock);
if (unlikely(d_unhashed(p))) {
spin_unlock(&p->d_lock);
goto out;
}
spin_unlock(&p->d_lock);
}
spin_lock(&dentry->d_lock);
if (!d_unlinked(dentry)) {
dentry->d_flags |= DCACHE_MOUNTED;
ret = 0;
}
spin_unlock(&dentry->d_lock);
out:
write_sequnlock(&rename_lock);
return ret;
}
/*
* Search the dentry child list of the specified parent,
* and move any unused dentries to the end of the unused
@ -1130,93 +1230,46 @@ EXPORT_SYMBOL(have_submounts);
* drop the lock and return early due to latency
* constraints.
*/
static int select_parent(struct dentry *parent, struct list_head *dispose)
struct select_data {
struct dentry *start;
struct list_head dispose;
int found;
};
static enum d_walk_ret select_collect(void *_data, struct dentry *dentry)
{
struct dentry *this_parent;
struct list_head *next;
unsigned seq;
int found = 0;
int locked = 0;
struct select_data *data = _data;
enum d_walk_ret ret = D_WALK_CONTINUE;
seq = read_seqbegin(&rename_lock);
again:
this_parent = parent;
spin_lock(&this_parent->d_lock);
repeat:
next = this_parent->d_subdirs.next;
resume:
while (next != &this_parent->d_subdirs) {
struct list_head *tmp = next;
struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
next = tmp->next;
if (data->start == dentry)
goto out;
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
/*
* move only zero ref count dentries to the dispose list.
*
* Those which are presently on the shrink list, being processed
* by shrink_dentry_list(), shouldn't be moved. Otherwise the
* loop in shrink_dcache_parent() might not make any progress
* and loop forever.
*/
if (dentry->d_lockref.count) {
dentry_lru_del(dentry);
} else if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) {
dentry_lru_move_list(dentry, dispose);
dentry->d_flags |= DCACHE_SHRINK_LIST;
found++;
}
/*
* We can return to the caller if we have found some (this
* ensures forward progress). We'll be coming back to find
* the rest.
*/
if (found && need_resched()) {
spin_unlock(&dentry->d_lock);
goto out;
}
/*
* Descend a level if the d_subdirs list is non-empty.
*/
if (!list_empty(&dentry->d_subdirs)) {
spin_unlock(&this_parent->d_lock);
spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_);
this_parent = dentry;
spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_);
goto repeat;
}
spin_unlock(&dentry->d_lock);
/*
* move only zero ref count dentries to the dispose list.
*
* Those which are presently on the shrink list, being processed
* by shrink_dentry_list(), shouldn't be moved. Otherwise the
* loop in shrink_dcache_parent() might not make any progress
* and loop forever.
*/
if (dentry->d_lockref.count) {
dentry_lru_del(dentry);
} else if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) {
dentry_lru_move_list(dentry, &data->dispose);
dentry->d_flags |= DCACHE_SHRINK_LIST;
data->found++;
ret = D_WALK_NORETRY;
}
/*
* All done at this level ... ascend and resume the search.
* We can return to the caller if we have found some (this
* ensures forward progress). We'll be coming back to find
* the rest.
*/
if (this_parent != parent) {
struct dentry *child = this_parent;
this_parent = try_to_ascend(this_parent, locked, seq);
if (!this_parent)
goto rename_retry;
next = child->d_u.d_child.next;
goto resume;
}
if (data->found && need_resched())
ret = D_WALK_QUIT;
out:
spin_unlock(&this_parent->d_lock);
if (!locked && read_seqretry(&rename_lock, seq))
goto rename_retry;
if (locked)
write_sequnlock(&rename_lock);
return found;
rename_retry:
if (found)
return found;
if (locked)
goto again;
locked = 1;
write_seqlock(&rename_lock);
goto again;
return ret;
}
/**
@ -1225,18 +1278,90 @@ static int select_parent(struct dentry *parent, struct list_head *dispose)
*
* Prune the dcache to remove unused children of the parent dentry.
*/
void shrink_dcache_parent(struct dentry * parent)
void shrink_dcache_parent(struct dentry *parent)
{
LIST_HEAD(dispose);
int found;
for (;;) {
struct select_data data;
while ((found = select_parent(parent, &dispose)) != 0) {
shrink_dentry_list(&dispose);
INIT_LIST_HEAD(&data.dispose);
data.start = parent;
data.found = 0;
d_walk(parent, &data, select_collect, NULL);
if (!data.found)
break;
shrink_dentry_list(&data.dispose);
cond_resched();
}
}
EXPORT_SYMBOL(shrink_dcache_parent);
static enum d_walk_ret check_and_collect(void *_data, struct dentry *dentry)
{
struct select_data *data = _data;
if (d_mountpoint(dentry)) {
data->found = -EBUSY;
return D_WALK_QUIT;
}
return select_collect(_data, dentry);
}
static void check_and_drop(void *_data)
{
struct select_data *data = _data;
if (d_mountpoint(data->start))
data->found = -EBUSY;
if (!data->found)
__d_drop(data->start);
}
/**
* check_submounts_and_drop - prune dcache, check for submounts and drop
*
* All done as a single atomic operation relative to has_unlinked_ancestor().
* Returns 0 if successfully unhashed @parent. If there were submounts then
* return -EBUSY.
*
* @dentry: dentry to prune and drop
*/
int check_submounts_and_drop(struct dentry *dentry)
{
int ret = 0;
/* Negative dentries can be dropped without further checks */
if (!dentry->d_inode) {
d_drop(dentry);
goto out;
}
for (;;) {
struct select_data data;
INIT_LIST_HEAD(&data.dispose);
data.start = dentry;
data.found = 0;
d_walk(dentry, &data, check_and_collect, check_and_drop);
ret = data.found;
if (!list_empty(&data.dispose))
shrink_dentry_list(&data.dispose);
if (ret <= 0)
break;
cond_resched();
}
out:
return ret;
}
EXPORT_SYMBOL(check_submounts_and_drop);
/**
* __d_alloc - allocate a dcache entry
* @sb: filesystem it will belong to
@ -2928,68 +3053,24 @@ int is_subdir(struct dentry *new_dentry, struct dentry *old_dentry)
return result;
}
void d_genocide(struct dentry *root)
static enum d_walk_ret d_genocide_kill(void *data, struct dentry *dentry)
{
struct dentry *this_parent;
struct list_head *next;
unsigned seq;
int locked = 0;
struct dentry *root = data;
if (dentry != root) {
if (d_unhashed(dentry) || !dentry->d_inode)
return D_WALK_SKIP;
seq = read_seqbegin(&rename_lock);
again:
this_parent = root;
spin_lock(&this_parent->d_lock);
repeat:
next = this_parent->d_subdirs.next;
resume:
while (next != &this_parent->d_subdirs) {
struct list_head *tmp = next;
struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
next = tmp->next;
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
if (d_unhashed(dentry) || !dentry->d_inode) {
spin_unlock(&dentry->d_lock);
continue;
}
if (!list_empty(&dentry->d_subdirs)) {
spin_unlock(&this_parent->d_lock);
spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_);
this_parent = dentry;
spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_);
goto repeat;
}
if (!(dentry->d_flags & DCACHE_GENOCIDE)) {
dentry->d_flags |= DCACHE_GENOCIDE;
dentry->d_lockref.count--;
}
spin_unlock(&dentry->d_lock);
}
if (this_parent != root) {
struct dentry *child = this_parent;
if (!(this_parent->d_flags & DCACHE_GENOCIDE)) {
this_parent->d_flags |= DCACHE_GENOCIDE;
this_parent->d_lockref.count--;
}
this_parent = try_to_ascend(this_parent, locked, seq);
if (!this_parent)
goto rename_retry;
next = child->d_u.d_child.next;
goto resume;
}
spin_unlock(&this_parent->d_lock);
if (!locked && read_seqretry(&rename_lock, seq))
goto rename_retry;
if (locked)
write_sequnlock(&rename_lock);
return;
return D_WALK_CONTINUE;
}
rename_retry:
if (locked)
goto again;
locked = 1;
write_seqlock(&rename_lock);
goto again;
void d_genocide(struct dentry *parent)
{
d_walk(parent, parent, d_genocide_kill, NULL);
}
void d_tmpfile(struct dentry *dentry, struct inode *inode)

97
fs/fuse/dir.c
View file

@ -182,10 +182,11 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
struct inode *inode;
struct dentry *parent;
struct fuse_conn *fc;
int ret;
inode = ACCESS_ONCE(entry->d_inode);
if (inode && is_bad_inode(inode))
return 0;
goto invalid;
else if (fuse_dentry_time(entry) < get_jiffies_64()) {
int err;
struct fuse_entry_out outarg;
@ -195,20 +196,23 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
/* For negative dentries, always do a fresh lookup */
if (!inode)
return 0;
goto invalid;
ret = -ECHILD;
if (flags & LOOKUP_RCU)
return -ECHILD;
goto out;
fc = get_fuse_conn(inode);
req = fuse_get_req_nopages(fc);
ret = PTR_ERR(req);
if (IS_ERR(req))
return 0;
goto out;
forget = fuse_alloc_forget();
if (!forget) {
fuse_put_request(fc, req);
return 0;
ret = -ENOMEM;
goto out;
}
attr_version = fuse_get_attr_version(fc);
@ -227,7 +231,7 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
struct fuse_inode *fi = get_fuse_inode(inode);
if (outarg.nodeid != get_node_id(inode)) {
fuse_queue_forget(fc, forget, outarg.nodeid, 1);
return 0;
goto invalid;
}
spin_lock(&fc->lock);
fi->nlookup++;
@ -235,7 +239,7 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
}
kfree(forget);
if (err || (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
return 0;
goto invalid;
fuse_change_attributes(inode, &outarg.attr,
entry_attr_timeout(&outarg),
@ -249,7 +253,15 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
dput(parent);
}
}
return 1;
ret = 1;
out:
return ret;
invalid:
ret = 0;
if (check_submounts_and_drop(entry) != 0)
ret = 1;
goto out;
}
static int invalid_nodeid(u64 nodeid)
@ -267,26 +279,6 @@ int fuse_valid_type(int m)
S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
}
/*
* Add a directory inode to a dentry, ensuring that no other dentry
* refers to this inode. Called with fc->inst_mutex.
*/
static struct dentry *fuse_d_add_directory(struct dentry *entry,
struct inode *inode)
{
struct dentry *alias = d_find_alias(inode);
if (alias && !(alias->d_flags & DCACHE_DISCONNECTED)) {
/* This tries to shrink the subtree below alias */
fuse_invalidate_entry(alias);
dput(alias);
if (!hlist_empty(&inode->i_dentry))
return ERR_PTR(-EBUSY);
} else {
dput(alias);
}
return d_splice_alias(inode, entry);
}
int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
struct fuse_entry_out *outarg, struct inode **inode)
{
@ -345,6 +337,24 @@ int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
return err;
}
static struct dentry *fuse_materialise_dentry(struct dentry *dentry,
struct inode *inode)
{
struct dentry *newent;
if (inode && S_ISDIR(inode->i_mode)) {
struct fuse_conn *fc = get_fuse_conn(inode);
mutex_lock(&fc->inst_mutex);
newent = d_materialise_unique(dentry, inode);
mutex_unlock(&fc->inst_mutex);
} else {
newent = d_materialise_unique(dentry, inode);
}
return newent;
}
static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
unsigned int flags)
{
@ -352,7 +362,6 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
struct fuse_entry_out outarg;
struct inode *inode;
struct dentry *newent;
struct fuse_conn *fc = get_fuse_conn(dir);
bool outarg_valid = true;
err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,
@ -368,16 +377,10 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
if (inode && get_node_id(inode) == FUSE_ROOT_ID)
goto out_iput;
if (inode && S_ISDIR(inode->i_mode)) {
mutex_lock(&fc->inst_mutex);
newent = fuse_d_add_directory(entry, inode);
mutex_unlock(&fc->inst_mutex);
err = PTR_ERR(newent);
if (IS_ERR(newent))
goto out_iput;
} else {
newent = d_splice_alias(inode, entry);
}
newent = fuse_materialise_dentry(entry, inode);
err = PTR_ERR(newent);
if (IS_ERR(newent))
goto out_err;
entry = newent ? newent : entry;
if (outarg_valid)
@ -1275,18 +1278,10 @@ static int fuse_direntplus_link(struct file *file,
if (!inode)
goto out;
if (S_ISDIR(inode->i_mode)) {
mutex_lock(&fc->inst_mutex);
alias = fuse_d_add_directory(dentry, inode);
mutex_unlock(&fc->inst_mutex);
err = PTR_ERR(alias);
if (IS_ERR(alias)) {
iput(inode);
goto out;
}
} else {
alias = d_splice_alias(inode, dentry);
}
alias = fuse_materialise_dentry(dentry, inode);
err = PTR_ERR(alias);
if (IS_ERR(alias))
goto out;
if (alias) {
dput(dentry);

9
fs/gfs2/dentry.c
View file

@ -93,12 +93,9 @@ static int gfs2_drevalidate(struct dentry *dentry, unsigned int flags)
if (!had_lock)
gfs2_glock_dq_uninit(&d_gh);
invalid:
if (inode && S_ISDIR(inode->i_mode)) {
if (have_submounts(dentry))
goto valid;
shrink_dcache_parent(dentry);
}
d_drop(dentry);
if (check_submounts_and_drop(dentry) != 0)
goto valid;
dput(parent);
return 0;

1
fs/internal.h
View file

@ -126,6 +126,7 @@ extern int invalidate_inodes(struct super_block *, bool);
* dcache.c
*/
extern struct dentry *__d_alloc(struct super_block *, const struct qstr *);
extern int d_set_mounted(struct dentry *dentry);
/*
* read_write.c

11
fs/namespace.c
View file

@ -611,6 +611,7 @@ static struct mountpoint *new_mountpoint(struct dentry *dentry)
{
struct list_head *chain = mountpoint_hashtable + hash(NULL, dentry);
struct mountpoint *mp;
int ret;
list_for_each_entry(mp, chain, m_hash) {
if (mp->m_dentry == dentry) {
@ -626,14 +627,12 @@ static struct mountpoint *new_mountpoint(struct dentry *dentry)
if (!mp)
return ERR_PTR(-ENOMEM);
spin_lock(&dentry->d_lock);
if (d_unlinked(dentry)) {
spin_unlock(&dentry->d_lock);
ret = d_set_mounted(dentry);
if (ret) {
kfree(mp);
return ERR_PTR(-ENOENT);
return ERR_PTR(ret);
}
dentry->d_flags |= DCACHE_MOUNTED;
spin_unlock(&dentry->d_lock);
mp->m_dentry = dentry;
mp->m_count = 1;
list_add(&mp->m_hash, chain);

9
fs/nfs/dir.c
View file

@ -1135,14 +1135,13 @@ static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
if (inode && S_ISDIR(inode->i_mode)) {
/* Purge readdir caches. */
nfs_zap_caches(inode);
/* If we have submounts, don't unhash ! */
if (have_submounts(dentry))
goto out_valid;
if (dentry->d_flags & DCACHE_DISCONNECTED)
goto out_valid;
shrink_dcache_parent(dentry);
}
d_drop(dentry);
/* If we have submounts, don't unhash ! */
if (check_submounts_and_drop(dentry) != 0)
goto out_valid;
dput(parent);
dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is invalid\n",
__func__, dentry->d_parent->d_name.name,

20
fs/sysfs/dir.c
View file

@ -297,7 +297,6 @@ static int sysfs_dentry_delete(const struct dentry *dentry)
static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
{
struct sysfs_dirent *sd;
int is_dir;
int type;
if (flags & LOOKUP_RCU)
@ -341,18 +340,15 @@ static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
* is performed at its new name the dentry will be readded
* to the dcache hashes.
*/
is_dir = (sysfs_type(sd) == SYSFS_DIR);
mutex_unlock(&sysfs_mutex);
if (is_dir) {
/* If we have submounts we must allow the vfs caches
* to lie about the state of the filesystem to prevent
* leaks and other nasty things.
*/
if (have_submounts(dentry))
goto out_valid;
shrink_dcache_parent(dentry);
}
d_drop(dentry);
/* If we have submounts we must allow the vfs caches
* to lie about the state of the filesystem to prevent
* leaks and other nasty things.
*/
if (check_submounts_and_drop(dentry) != 0)
goto out_valid;
return 0;
}

13
include/linux/dcache.h
View file

@ -212,7 +212,7 @@ struct dentry_operations {
extern seqlock_t rename_lock;
static inline int dname_external(struct dentry *dentry)
static inline int dname_external(const struct dentry *dentry)
{
return dentry->d_name.name != dentry->d_iname;
}
@ -253,6 +253,7 @@ 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 check_submounts_and_drop(struct dentry *);
/*
* This adds the entry to the hash queues.
@ -357,17 +358,17 @@ extern struct dentry *dget_parent(struct dentry *dentry);
* Returns true if the dentry passed is not currently hashed.
*/
static inline int d_unhashed(struct dentry *dentry)
static inline int d_unhashed(const struct dentry *dentry)
{
return hlist_bl_unhashed(&dentry->d_hash);
}
static inline int d_unlinked(struct dentry *dentry)
static inline int d_unlinked(const struct dentry *dentry)
{
return d_unhashed(dentry) && !IS_ROOT(dentry);
}
static inline int cant_mount(struct dentry *dentry)
static inline int cant_mount(const struct dentry *dentry)
{
return (dentry->d_flags & DCACHE_CANT_MOUNT);
}
@ -381,12 +382,12 @@ static inline void dont_mount(struct dentry *dentry)
extern void dput(struct dentry *);
static inline bool d_managed(struct dentry *dentry)
static inline bool d_managed(const struct dentry *dentry)
{
return dentry->d_flags & DCACHE_MANAGED_DENTRY;
}
static inline bool d_mountpoint(struct dentry *dentry)
static inline bool d_mountpoint(const struct dentry *dentry)
{
return dentry->d_flags & DCACHE_MOUNTED;
}