Merge branch 'master' of /home/tglx/work/mtd/git/linux-2.6.git/

1 files changed, 145 insertions, 70 deletions

diff --git a/fs/open.c b/fs/open.c
index 32bf05e2996d..8d06ec911fd9 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -24,6 +24,7 @@
 #include <linux/personality.h>
 #include <linux/pagemap.h>
 #include <linux/syscalls.h>
+#include <linux/rcupdate.h>
 
 #include <asm/unistd.h>
 
@@ -737,52 +738,16 @@ asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group)
         return error;
 }
 
-/*
- * Note that while the flag value (low two bits) for sys_open means:
- *      00 - read-only
- *      01 - write-only
- *      10 - read-write
- *      11 - special
- * it is changed into
- *      00 - no permissions needed
- *      01 - read-permission
- *      10 - write-permission
- *      11 - read-write
- * for the internal routines (ie open_namei()/follow_link() etc). 00 is
- * used by symlinks.
- */
-struct file *filp_open(const char * filename, int flags, int mode)
-{
-        int namei_flags, error;
-        struct nameidata nd;
-
-        namei_flags = flags;
-        if ((namei_flags+1) & O_ACCMODE)
-                namei_flags++;
-        if (namei_flags & O_TRUNC)
-                namei_flags |= 2;
-
-        error = open_namei(filename, namei_flags, mode, &nd);
-        if (!error)
-                return dentry_open(nd.dentry, nd.mnt, flags);
-
-        return ERR_PTR(error);
-}
-
-EXPORT_SYMBOL(filp_open);
-
-struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
+static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
+                                        int flags, struct file *f,
+                                        int (*open)(struct inode *, struct file *))
 {
-        struct file * f;
         struct inode *inode;
         int error;
 
-        error = -ENFILE;
-        f = get_empty_filp();
-        if (!f)
-                goto cleanup_dentry;
         f->f_flags = flags;
-        f->f_mode = ((flags+1) & O_ACCMODE) | FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE;
+        f->f_mode = ((flags+1) & O_ACCMODE) | FMODE_LSEEK |
+                                FMODE_PREAD | FMODE_PWRITE;
         inode = dentry->d_inode;
         if (f->f_mode & FMODE_WRITE) {
                 error = get_write_access(inode);
@@ -797,11 +762,14 @@ struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
         f->f_op = fops_get(inode->i_fop);
         file_move(f, &inode->i_sb->s_files);
 
-        if (f->f_op && f->f_op->open) {
-                error = f->f_op->open(inode,f);
+        if (!open && f->f_op)
+                open = f->f_op->open;
+        if (open) {
+                error = open(inode, f);
                 if (error)
                         goto cleanup_all;
         }
+
         f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
 
         file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
@@ -827,12 +795,110 @@ cleanup_all:
         f->f_vfsmnt = NULL;
 cleanup_file:
         put_filp(f);
-cleanup_dentry:
         dput(dentry);
         mntput(mnt);
         return ERR_PTR(error);
 }
 
+/*
+ * Note that while the flag value (low two bits) for sys_open means:
+ *      00 - read-only
+ *      01 - write-only
+ *      10 - read-write
+ *      11 - special
+ * it is changed into
+ *      00 - no permissions needed
+ *      01 - read-permission
+ *      10 - write-permission
+ *      11 - read-write
+ * for the internal routines (ie open_namei()/follow_link() etc). 00 is
+ * used by symlinks.
+ */
+struct file *filp_open(const char * filename, int flags, int mode)
+{
+        int namei_flags, error;
+        struct nameidata nd;
+
+        namei_flags = flags;
+        if ((namei_flags+1) & O_ACCMODE)
+                namei_flags++;
+
+        error = open_namei(filename, namei_flags, mode, &nd);
+        if (!error)
+                return nameidata_to_filp(&nd, flags);
+
+        return ERR_PTR(error);
+}
+EXPORT_SYMBOL(filp_open);
+
+/**
+ * lookup_instantiate_filp - instantiates the open intent filp
+ * @nd: pointer to nameidata
+ * @dentry: pointer to dentry
+ * @open: open callback
+ *
+ * Helper for filesystems that want to use lookup open intents and pass back
+ * a fully instantiated struct file to the caller.
+ * This function is meant to be called from within a filesystem's
+ * lookup method.
+ * Note that in case of error, nd->intent.open.file is destroyed, but the
+ * path information remains valid.
+ * If the open callback is set to NULL, then the standard f_op->open()
+ * filesystem callback is substituted.
+ */
+struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
+                int (*open)(struct inode *, struct file *))
+{
+        if (IS_ERR(nd->intent.open.file))
+                goto out;
+        if (IS_ERR(dentry))
+                goto out_err;
+        nd->intent.open.file = __dentry_open(dget(dentry), mntget(nd->mnt),
+                                             nd->intent.open.flags - 1,
+                                             nd->intent.open.file,
+                                             open);
+out:
+        return nd->intent.open.file;
+out_err:
+        release_open_intent(nd);
+        nd->intent.open.file = (struct file *)dentry;
+        goto out;
+}
+EXPORT_SYMBOL_GPL(lookup_instantiate_filp);
+
+/**
+ * nameidata_to_filp - convert a nameidata to an open filp.
+ * @nd: pointer to nameidata
+ * @flags: open flags
+ *
+ * Note that this function destroys the original nameidata
+ */
+struct file *nameidata_to_filp(struct nameidata *nd, int flags)
+{
+        struct file *filp;
+
+        /* Pick up the filp from the open intent */
+        filp = nd->intent.open.file;
+        /* Has the filesystem initialised the file for us? */
+        if (filp->f_dentry == NULL)
+                filp = __dentry_open(nd->dentry, nd->mnt, flags, filp, NULL);
+        else
+                path_release(nd);
+        return filp;
+}
+
+struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
+{
+        int error;
+        struct file *f;
+
+        error = -ENFILE;
+        f = get_empty_filp();
+        if (f == NULL)
+                return ERR_PTR(error);
+
+        return __dentry_open(dentry, mnt, flags, f, NULL);
+}
 EXPORT_SYMBOL(dentry_open);
 
 /*
@@ -842,14 +908,16 @@ int get_unused_fd(void)
 {
         struct files_struct * files = current->files;
         int fd, error;
+        struct fdtable *fdt;
 
         error = -EMFILE;
         spin_lock(&files->file_lock);
 
 repeat:
-        fd = find_next_zero_bit(files->open_fds->fds_bits, 
-                                files->max_fdset, 
-                                files->next_fd);
+        fdt = files_fdtable(files);
+        fd = find_next_zero_bit(fdt->open_fds->fds_bits,
+                                fdt->max_fdset,
+                                fdt->next_fd);
 
         /*
          * N.B. For clone tasks sharing a files structure, this test
@@ -872,14 +940,14 @@ repeat:
                 goto repeat;
         }
 
-        FD_SET(fd, files->open_fds);
-        FD_CLR(fd, files->close_on_exec);
-        files->next_fd = fd + 1;
+        FD_SET(fd, fdt->open_fds);
+        FD_CLR(fd, fdt->close_on_exec);
+        fdt->next_fd = fd + 1;
 #if 1
         /* Sanity check */
-        if (files->fd[fd] != NULL) {
+        if (fdt->fd[fd] != NULL) {
                 printk(KERN_WARNING "get_unused_fd: slot %d not NULL!\n", fd);
-                files->fd[fd] = NULL;
+                fdt->fd[fd] = NULL;
         }
 #endif
         error = fd;
@@ -893,9 +961,10 @@ EXPORT_SYMBOL(get_unused_fd);
 
 static inline void __put_unused_fd(struct files_struct *files, unsigned int fd)
 {
-        __FD_CLR(fd, files->open_fds);
-        if (fd < files->next_fd)
-                files->next_fd = fd;
+        struct fdtable *fdt = files_fdtable(files);
+        __FD_CLR(fd, fdt->open_fds);
+        if (fd < fdt->next_fd)
+                fdt->next_fd = fd;
 }
 
 void fastcall put_unused_fd(unsigned int fd)
@@ -924,25 +993,21 @@ EXPORT_SYMBOL(put_unused_fd);
 void fastcall fd_install(unsigned int fd, struct file * file)
 {
         struct files_struct *files = current->files;
+        struct fdtable *fdt;
         spin_lock(&files->file_lock);
-        if (unlikely(files->fd[fd] != NULL))
-                BUG();
-        files->fd[fd] = file;
+        fdt = files_fdtable(files);
+        BUG_ON(fdt->fd[fd] != NULL);
+        rcu_assign_pointer(fdt->fd[fd], file);
         spin_unlock(&files->file_lock);
 }
 
 EXPORT_SYMBOL(fd_install);
 
-asmlinkage long sys_open(const char __user * filename, int flags, int mode)
+long do_sys_open(const char __user *filename, int flags, int mode)
 {
-        char * tmp;
-        int fd;
-
-        if (force_o_largefile())
-                flags |= O_LARGEFILE;
+        char *tmp = getname(filename);
+        int fd = PTR_ERR(tmp);
 
-        tmp = getname(filename);
-        fd = PTR_ERR(tmp);
         if (!IS_ERR(tmp)) {
                 fd = get_unused_fd();
                 if (fd >= 0) {
@@ -959,6 +1024,14 @@ asmlinkage long sys_open(const char __user * filename, int flags, int mode)
         }
         return fd;
 }
+
+asmlinkage long sys_open(const char __user *filename, int flags, int mode)
+{
+        if (force_o_largefile())
+                flags |= O_LARGEFILE;
+
+        return do_sys_open(filename, flags, mode);
+}
 EXPORT_SYMBOL_GPL(sys_open);
 
 #ifndef __alpha__
@@ -1007,15 +1080,17 @@ asmlinkage long sys_close(unsigned int fd)
 {
         struct file * filp;
         struct files_struct *files = current->files;
+        struct fdtable *fdt;
 
         spin_lock(&files->file_lock);
-        if (fd >= files->max_fds)
+        fdt = files_fdtable(files);
+        if (fd >= fdt->max_fds)
                 goto out_unlock;
-        filp = files->fd[fd];
+        filp = fdt->fd[fd];
         if (!filp)
                 goto out_unlock;
-        files->fd[fd] = NULL;
-        FD_CLR(fd, files->close_on_exec);
+        rcu_assign_pointer(fdt->fd[fd], NULL);
+        FD_CLR(fd, fdt->close_on_exec);
         __put_unused_fd(files, fd);
         spin_unlock(&files->file_lock);
         return filp_close(filp, files);