fs: dcache scale d_unhashed
Protect d_unhashed(dentry) condition with d_lock. This means keeping DCACHE_UNHASHED bit in synch with hash manipulations. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
This commit is contained in:
29
fs/libfs.c
29
fs/libfs.c
@ -16,6 +16,11 @@
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#include <asm/uaccess.h>
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static inline int simple_positive(struct dentry *dentry)
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{
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return dentry->d_inode && !d_unhashed(dentry);
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}
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int simple_getattr(struct vfsmount *mnt, struct dentry *dentry,
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struct kstat *stat)
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{
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@ -100,8 +105,10 @@ loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin)
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while (n && p != &file->f_path.dentry->d_subdirs) {
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struct dentry *next;
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next = list_entry(p, struct dentry, d_u.d_child);
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if (!d_unhashed(next) && next->d_inode)
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spin_lock(&next->d_lock);
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if (simple_positive(next))
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n--;
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spin_unlock(&next->d_lock);
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p = p->next;
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}
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list_add_tail(&cursor->d_u.d_child, p);
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@ -155,9 +162,13 @@ int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
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for (p=q->next; p != &dentry->d_subdirs; p=p->next) {
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struct dentry *next;
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next = list_entry(p, struct dentry, d_u.d_child);
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if (d_unhashed(next) || !next->d_inode)
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spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
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if (!simple_positive(next)) {
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spin_unlock(&next->d_lock);
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continue;
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}
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spin_unlock(&next->d_lock);
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spin_unlock(&dcache_lock);
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if (filldir(dirent, next->d_name.name,
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next->d_name.len, filp->f_pos,
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@ -259,20 +270,20 @@ int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *den
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return 0;
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}
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static inline int simple_positive(struct dentry *dentry)
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{
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return dentry->d_inode && !d_unhashed(dentry);
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}
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int simple_empty(struct dentry *dentry)
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{
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struct dentry *child;
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int ret = 0;
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spin_lock(&dcache_lock);
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list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child)
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if (simple_positive(child))
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list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) {
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spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
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if (simple_positive(child)) {
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spin_unlock(&child->d_lock);
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goto out;
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}
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spin_unlock(&child->d_lock);
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}
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ret = 1;
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out:
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spin_unlock(&dcache_lock);
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