#include <linux/fsnotify.h>
#include <linux/slab.h>
#include <linux/init.h>
-#include <linux/smp_lock.h>
#include <linux/hash.h>
#include <linux/cache.h>
#include <linux/module.h>
EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure);
__cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_lock);
-static __cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock);
+__cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock);
EXPORT_SYMBOL(dcache_lock);
if (dentry->d_op && dentry->d_op->d_release)
dentry->d_op->d_release(dentry);
/* if dentry was never inserted into hash, immediate free is OK */
- if (dentry->d_hash.pprev == NULL)
+ if (hlist_unhashed(&dentry->d_hash))
__d_free(dentry);
else
call_rcu(&dentry->d_u.d_rcu, d_callback);
}
+static void dentry_lru_remove(struct dentry *dentry)
+{
+ if (!list_empty(&dentry->d_lru)) {
+ list_del_init(&dentry->d_lru);
+ dentry_stat.nr_unused--;
+ }
+}
+
/*
* Release the dentry's inode, using the filesystem
* d_iput() operation if defined.
unhash_it:
__d_drop(dentry);
kill_it:
- /* If dentry was on d_lru list
- * delete it from there
- */
- if (!list_empty(&dentry->d_lru)) {
- list_del(&dentry->d_lru);
- dentry_stat.nr_unused--;
- }
+ dentry_lru_remove(dentry);
dentry = d_kill(dentry);
if (dentry)
goto repeat;
static inline struct dentry * __dget_locked(struct dentry *dentry)
{
atomic_inc(&dentry->d_count);
- if (!list_empty(&dentry->d_lru)) {
- dentry_stat.nr_unused--;
- list_del_init(&dentry->d_lru);
- }
+ dentry_lru_remove(dentry);
return dentry;
}
* Throw away a dentry - free the inode, dput the parent. This requires that
* the LRU list has already been removed.
*
- * If prune_parents is true, try to prune ancestors as well.
+ * Try to prune ancestors as well. This is necessary to prevent
+ * quadratic behavior of shrink_dcache_parent(), but is also expected
+ * to be beneficial in reducing dentry cache fragmentation.
*
* Called with dcache_lock, drops it and then regains.
* Called with dentry->d_lock held, drops it.
*/
-static void prune_one_dentry(struct dentry * dentry, int prune_parents)
+static void prune_one_dentry(struct dentry * dentry)
{
__d_drop(dentry);
dentry = d_kill(dentry);
- if (!prune_parents) {
- dput(dentry);
- spin_lock(&dcache_lock);
- return;
- }
/*
* Prune ancestors. Locking is simpler than in dput(),
if (dentry->d_op && dentry->d_op->d_delete)
dentry->d_op->d_delete(dentry);
- if (!list_empty(&dentry->d_lru)) {
- list_del(&dentry->d_lru);
- dentry_stat.nr_unused--;
- }
+ dentry_lru_remove(dentry);
__d_drop(dentry);
dentry = d_kill(dentry);
spin_lock(&dcache_lock);
* @count: number of entries to try and free
* @sb: if given, ignore dentries for other superblocks
* which are being unmounted.
- * @prune_parents: if true, try to prune ancestors as well in one go
*
* Shrink the dcache. This is done when we need
* more memory, or simply when we need to unmount
* all the dentries are in use.
*/
-static void prune_dcache(int count, struct super_block *sb, int prune_parents)
+static void prune_dcache(int count, struct super_block *sb)
{
spin_lock(&dcache_lock);
for (; count ; count--) {
* without taking the s_umount lock (I already hold it).
*/
if (sb && dentry->d_sb == sb) {
- prune_one_dentry(dentry, prune_parents);
+ prune_one_dentry(dentry);
continue;
}
/*
s_umount = &dentry->d_sb->s_umount;
if (down_read_trylock(s_umount)) {
if (dentry->d_sb->s_root != NULL) {
- prune_one_dentry(dentry, prune_parents);
+ prune_one_dentry(dentry);
up_read(s_umount);
continue;
}
* superblock to the most recent end of the unused list.
*/
spin_lock(&dcache_lock);
- list_for_each_safe(tmp, next, &dentry_unused) {
+ list_for_each_prev_safe(tmp, next, &dentry_unused) {
dentry = list_entry(tmp, struct dentry, d_lru);
if (dentry->d_sb != sb)
continue;
- list_move(tmp, &dentry_unused);
+ list_move_tail(tmp, &dentry_unused);
}
/*
* Pass two ... free the dentries for this superblock.
*/
repeat:
- list_for_each_safe(tmp, next, &dentry_unused) {
+ list_for_each_prev_safe(tmp, next, &dentry_unused) {
dentry = list_entry(tmp, struct dentry, d_lru);
if (dentry->d_sb != sb)
continue;
spin_unlock(&dentry->d_lock);
continue;
}
- prune_one_dentry(dentry, 1);
+ prune_one_dentry(dentry);
cond_resched_lock(&dcache_lock);
goto repeat;
}
/* detach this root from the system */
spin_lock(&dcache_lock);
- if (!list_empty(&dentry->d_lru)) {
- dentry_stat.nr_unused--;
- list_del_init(&dentry->d_lru);
- }
+ dentry_lru_remove(dentry);
__d_drop(dentry);
spin_unlock(&dcache_lock);
spin_lock(&dcache_lock);
list_for_each_entry(loop, &dentry->d_subdirs,
d_u.d_child) {
- if (!list_empty(&loop->d_lru)) {
- dentry_stat.nr_unused--;
- list_del_init(&loop->d_lru);
- }
-
+ dentry_lru_remove(loop);
__d_drop(loop);
cond_resched_lock(&dcache_lock);
}
struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
next = tmp->next;
- if (!list_empty(&dentry->d_lru)) {
- dentry_stat.nr_unused--;
- list_del_init(&dentry->d_lru);
- }
+ dentry_lru_remove(dentry);
/*
* move only zero ref count dentries to the end
* of the unused list for prune_dcache
int found;
while ((found = select_parent(parent)) != 0)
- prune_dcache(found, parent->d_sb, 1);
+ prune_dcache(found, parent->d_sb);
}
/*
if (nr) {
if (!(gfp_mask & __GFP_FS))
return -1;
- prune_dcache(nr, NULL, 0);
+ prune_dcache(nr, NULL);
}
return (dentry_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
}
+static struct shrinker dcache_shrinker = {
+ .shrink = shrink_dcache_memory,
+ .seeks = DEFAULT_SEEKS,
+};
+
/**
* d_alloc - allocate a dcache entry
* @parent: parent of entry to allocate
struct dentry *dentry;
char *dname;
- dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL);
+ dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL);
if (!dentry)
return NULL;
if (atomic_read(&dentry->d_count) == 1) {
dentry_iput(dentry);
fsnotify_nameremove(dentry, isdir);
-
- /* remove this and other inotify debug checks after 2.6.18 */
- dentry->d_flags &= ~DCACHE_INOTIFY_PARENT_WATCHED;
return;
}
* dentry:internal, target:external. Steal target's
* storage and make target internal.
*/
+ memcpy(target->d_iname, dentry->d_name.name,
+ dentry->d_name.len + 1);
dentry->d_name.name = target->d_name.name;
target->d_name.name = target->d_iname;
}
* This forceful removal will result in ugly /proc output if
* somebody holds a file open that got deleted due to a rename.
* We could be nicer about the deleted file, and let it show
- * up under the name it got deleted rather than the name that
- * deleted it.
+ * up under the name it had before it was deleted rather than
+ * under the original name of the file that was moved on top of it.
*/
/*
}
/* Move the dentry to the target hash queue, if on different bucket */
- if (dentry->d_flags & DCACHE_UNHASHED)
+ if (d_unhashed(dentry))
goto already_unhashed;
hlist_del_rcu(&dentry->d_hash);
goto shouldnt_be_hashed;
}
+static int prepend(char **buffer, int *buflen, const char *str,
+ int namelen)
+{
+ *buflen -= namelen;
+ if (*buflen < 0)
+ return -ENAMETOOLONG;
+ *buffer -= namelen;
+ memcpy(*buffer, str, namelen);
+ return 0;
+}
+
/**
* d_path - return the path of a dentry
- * @dentry: dentry to report
- * @vfsmnt: vfsmnt to which the dentry belongs
- * @root: root dentry
- * @rootmnt: vfsmnt to which the root dentry belongs
+ * @path: the dentry/vfsmount to report
+ * @root: root vfsmnt/dentry (may be modified by this function)
* @buffer: buffer to return value in
* @buflen: buffer length
*
* Returns the buffer or an error code if the path was too long.
*
* "buflen" should be positive. Caller holds the dcache_lock.
+ *
+ * If path is not reachable from the supplied root, then the value of
+ * root is changed (without modifying refcounts).
*/
-static char * __d_path( struct dentry *dentry, struct vfsmount *vfsmnt,
- struct dentry *root, struct vfsmount *rootmnt,
- char *buffer, int buflen)
+char *__d_path(const struct path *path, struct path *root,
+ char *buffer, int buflen)
{
+ struct dentry *dentry = path->dentry;
+ struct vfsmount *vfsmnt = path->mnt;
char * end = buffer+buflen;
char * retval;
- int namelen;
-
- *--end = '\0';
- buflen--;
- if (!IS_ROOT(dentry) && d_unhashed(dentry)) {
- buflen -= 10;
- end -= 10;
- if (buflen < 0)
+
+ prepend(&end, &buflen, "\0", 1);
+ if (!IS_ROOT(dentry) && d_unhashed(dentry) &&
+ (prepend(&end, &buflen, " (deleted)", 10) != 0))
goto Elong;
- memcpy(end, " (deleted)", 10);
- }
if (buflen < 1)
goto Elong;
for (;;) {
struct dentry * parent;
- if (dentry == root && vfsmnt == rootmnt)
+ if (dentry == root->dentry && vfsmnt == root->mnt)
break;
if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) {
/* Global root? */
}
parent = dentry->d_parent;
prefetch(parent);
- namelen = dentry->d_name.len;
- buflen -= namelen + 1;
- if (buflen < 0)
+ if ((prepend(&end, &buflen, dentry->d_name.name,
+ dentry->d_name.len) != 0) ||
+ (prepend(&end, &buflen, "/", 1) != 0))
goto Elong;
- end -= namelen;
- memcpy(end, dentry->d_name.name, namelen);
- *--end = '/';
retval = end;
dentry = parent;
}
return retval;
global_root:
- namelen = dentry->d_name.len;
- buflen -= namelen;
- if (buflen < 0)
+ retval += 1; /* hit the slash */
+ if (prepend(&retval, &buflen, dentry->d_name.name,
+ dentry->d_name.len) != 0)
goto Elong;
- retval -= namelen-1; /* hit the slash */
- memcpy(retval, dentry->d_name.name, namelen);
+ root->mnt = vfsmnt;
+ root->dentry = dentry;
return retval;
Elong:
return ERR_PTR(-ENAMETOOLONG);
}
-/* write full pathname into buffer and return start of pathname */
-char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt,
- char *buf, int buflen)
+/**
+ * d_path - return the path of a dentry
+ * @path: path to report
+ * @buf: buffer to return value in
+ * @buflen: buffer length
+ *
+ * Convert a dentry into an ASCII path name. If the entry has been deleted
+ * the string " (deleted)" is appended. Note that this is ambiguous.
+ *
+ * Returns the buffer or an error code if the path was too long.
+ *
+ * "buflen" should be positive. Caller holds the dcache_lock.
+ */
+char *d_path(struct path *path, char *buf, int buflen)
{
char *res;
- struct vfsmount *rootmnt;
- struct dentry *root;
+ struct path root;
+ struct path tmp;
+
+ /*
+ * We have various synthetic filesystems that never get mounted. On
+ * these filesystems dentries are never used for lookup purposes, and
+ * thus don't need to be hashed. They also don't need a name until a
+ * user wants to identify the object in /proc/pid/fd/. The little hack
+ * below allows us to generate a name for these objects on demand:
+ */
+ if (path->dentry->d_op && path->dentry->d_op->d_dname)
+ return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
read_lock(¤t->fs->lock);
- rootmnt = mntget(current->fs->rootmnt);
- root = dget(current->fs->root);
+ root = current->fs->root;
+ path_get(&root);
read_unlock(¤t->fs->lock);
spin_lock(&dcache_lock);
- res = __d_path(dentry, vfsmnt, root, rootmnt, buf, buflen);
+ tmp = root;
+ res = __d_path(path, &tmp, buf, buflen);
spin_unlock(&dcache_lock);
- dput(root);
- mntput(rootmnt);
+ path_put(&root);
return res;
}
/*
+ * Helper function for dentry_operations.d_dname() members
+ */
+char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen,
+ const char *fmt, ...)
+{
+ va_list args;
+ char temp[64];
+ int sz;
+
+ va_start(args, fmt);
+ sz = vsnprintf(temp, sizeof(temp), fmt, args) + 1;
+ va_end(args);
+
+ if (sz > sizeof(temp) || sz > buflen)
+ return ERR_PTR(-ENAMETOOLONG);
+
+ buffer += buflen - sz;
+ return memcpy(buffer, temp, sz);
+}
+
+/*
+ * Write full pathname from the root of the filesystem into the buffer.
+ */
+char *dentry_path(struct dentry *dentry, char *buf, int buflen)
+{
+ char *end = buf + buflen;
+ char *retval;
+
+ spin_lock(&dcache_lock);
+ prepend(&end, &buflen, "\0", 1);
+ if (!IS_ROOT(dentry) && d_unhashed(dentry) &&
+ (prepend(&end, &buflen, "//deleted", 9) != 0))
+ goto Elong;
+ if (buflen < 1)
+ goto Elong;
+ /* Get '/' right */
+ retval = end-1;
+ *retval = '/';
+
+ for (;;) {
+ struct dentry *parent;
+ if (IS_ROOT(dentry))
+ break;
+
+ parent = dentry->d_parent;
+ prefetch(parent);
+
+ if ((prepend(&end, &buflen, dentry->d_name.name,
+ dentry->d_name.len) != 0) ||
+ (prepend(&end, &buflen, "/", 1) != 0))
+ goto Elong;
+
+ retval = end;
+ dentry = parent;
+ }
+ spin_unlock(&dcache_lock);
+ return retval;
+Elong:
+ spin_unlock(&dcache_lock);
+ return ERR_PTR(-ENAMETOOLONG);
+}
+
+/*
* NOTE! The user-level library version returns a
* character pointer. The kernel system call just
* returns the length of the buffer filled (which
asmlinkage long sys_getcwd(char __user *buf, unsigned long size)
{
int error;
- struct vfsmount *pwdmnt, *rootmnt;
- struct dentry *pwd, *root;
+ struct path pwd, root;
char *page = (char *) __get_free_page(GFP_USER);
if (!page)
return -ENOMEM;
read_lock(¤t->fs->lock);
- pwdmnt = mntget(current->fs->pwdmnt);
- pwd = dget(current->fs->pwd);
- rootmnt = mntget(current->fs->rootmnt);
- root = dget(current->fs->root);
+ pwd = current->fs->pwd;
+ path_get(&pwd);
+ root = current->fs->root;
+ path_get(&root);
read_unlock(¤t->fs->lock);
error = -ENOENT;
/* Has the current directory has been unlinked? */
spin_lock(&dcache_lock);
- if (pwd->d_parent == pwd || !d_unhashed(pwd)) {
+ if (pwd.dentry->d_parent == pwd.dentry || !d_unhashed(pwd.dentry)) {
unsigned long len;
+ struct path tmp = root;
char * cwd;
- cwd = __d_path(pwd, pwdmnt, root, rootmnt, page, PAGE_SIZE);
+ cwd = __d_path(&pwd, &tmp, page, PAGE_SIZE);
spin_unlock(&dcache_lock);
error = PTR_ERR(cwd);
spin_unlock(&dcache_lock);
out:
- dput(pwd);
- mntput(pwdmnt);
- dput(root);
- mntput(rootmnt);
+ path_put(&pwd);
+ path_put(&root);
free_page((unsigned long) page);
return error;
}
INIT_HLIST_HEAD(&dentry_hashtable[loop]);
}
-static void __init dcache_init(unsigned long mempages)
+static void __init dcache_init(void)
{
int loop;
dentry_cache = KMEM_CACHE(dentry,
SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD);
- set_shrinker(DEFAULT_SEEKS, shrink_dcache_memory);
+ register_shrinker(&dcache_shrinker);
/* Hash may have been set up in dcache_init_early */
if (!hashdist)
mempages -= reserve;
names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0,
- SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
+ SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0,
- SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
+ SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
- dcache_init(mempages);
- inode_init(mempages);
+ dcache_init();
+ inode_init();
files_init(mempages);
- mnt_init(mempages);
+ mnt_init();
bdev_cache_init();
chrdev_init();
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff