[readdir] introduce iterate_dir() and dir_context

iterate_dir(): new helper, replacing vfs_readdir().

struct dir_context: contains the readdir callback (and will get more stuff
in it), embedded into whatever data that callback wants to deal with;
eventually, we'll be passing it to ->readdir() replacement instead of
(data,filldir) pair.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

6 files changed, 40 insertions, 18 deletions

diff --git a/fs/compat.c b/fs/compat.c
index fc3b55dce184..2279b59e81f2 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -832,6 +832,7 @@ struct compat_old_linux_dirent {
 };
 
 struct compat_readdir_callback {
+        struct dir_context ctx;
         struct compat_old_linux_dirent __user *dirent;
         int result;
 };
@@ -880,8 +881,9 @@ asmlinkage long compat_sys_old_readdir(unsigned int fd,
 
         buf.result = 0;
         buf.dirent = dirent;
+        buf.ctx.actor = compat_fillonedir;
 
-        error = vfs_readdir(f.file, compat_fillonedir, &buf);
+        error = iterate_dir(f.file, &buf.ctx);
         if (buf.result)
                 error = buf.result;
 
@@ -897,6 +899,7 @@ struct compat_linux_dirent {
 };
 
 struct compat_getdents_callback {
+        struct dir_context ctx;
         struct compat_linux_dirent __user *current_dir;
         struct compat_linux_dirent __user *previous;
         int count;
@@ -965,8 +968,9 @@ asmlinkage long compat_sys_getdents(unsigned int fd,
         buf.previous = NULL;
         buf.count = count;
         buf.error = 0;
+        buf.ctx.actor = compat_filldir;
 
-        error = vfs_readdir(f.file, compat_filldir, &buf);
+        error = iterate_dir(f.file, &buf.ctx);
         if (error >= 0)
                 error = buf.error;
         lastdirent = buf.previous;
@@ -983,6 +987,7 @@ asmlinkage long compat_sys_getdents(unsigned int fd,
 #ifndef __ARCH_OMIT_COMPAT_SYS_GETDENTS64
 
 struct compat_getdents_callback64 {
+        struct dir_context ctx;
         struct linux_dirent64 __user *current_dir;
         struct linux_dirent64 __user *previous;
         int count;
@@ -1050,8 +1055,9 @@ asmlinkage long compat_sys_getdents64(unsigned int fd,
         buf.previous = NULL;
         buf.count = count;
         buf.error = 0;
+        buf.ctx.actor = compat_filldir64;
 
-        error = vfs_readdir(f.file, compat_filldir64, &buf);
+        error = iterate_dir(f.file, &buf.ctx);
         if (error >= 0)
                 error = buf.error;
         lastdirent = buf.previous;
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index a7abbea2c096..041379a646b3 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -68,6 +68,7 @@ static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
 }
 
 struct ecryptfs_getdents_callback {
+        struct dir_context ctx;
         void *dirent;
         struct dentry *dentry;
         filldir_t filldir;
@@ -126,7 +127,8 @@ static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir)
         buf.filldir = filldir;
         buf.filldir_called = 0;
         buf.entries_written = 0;
-        rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
+        buf.ctx.actor = ecryptfs_filldir;
+        rc = iterate_dir(lower_file, &buf.ctx);
         file->f_pos = lower_file->f_pos;
         if (rc < 0)
                 goto out;
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index 262fc9940982..7cb190426cec 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -212,6 +212,7 @@ reconnect_path(struct vfsmount *mnt, struct dentry *target_dir, char *nbuf)
 }
 
 struct getdents_callback {
+        struct dir_context ctx;
         char *name;             /* name that was found. It already points to a
                                    buffer NAME_MAX+1 is size */
         unsigned long ino;      /* the inum we are looking for */
@@ -278,10 +279,11 @@ static int get_name(const struct path *path, char *name, struct dentry *child)
         buffer.ino = child->d_inode->i_ino;
         buffer.found = 0;
         buffer.sequence = 0;
+        buffer.ctx.actor = filldir_one;
         while (1) {
                 int old_seq = buffer.sequence;
 
-                error = vfs_readdir(file, filldir_one, &buffer);
+                error = iterate_dir(file, &buffer.ctx);
                 if (buffer.found) {
                         error = 0;
                         break;
diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 4e9a21db867a..4f8cc6ba7c28 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -263,7 +263,10 @@ nfsd4_list_rec_dir(recdir_func *f, struct nfsd_net *nn)
 {
         const struct cred *original_cred;
         struct dentry *dir = nn->rec_file->f_path.dentry;
-        LIST_HEAD(names);
+        struct {
+                struct dir_context ctx;
+                struct list_head names;
+        } ctx;
         int status;
 
         status = nfs4_save_creds(&original_cred);
@@ -276,11 +279,13 @@ nfsd4_list_rec_dir(recdir_func *f, struct nfsd_net *nn)
                 return status;
         }
 
-        status = vfs_readdir(nn->rec_file, nfsd4_build_namelist, &names);
+        INIT_LIST_HEAD(&ctx.names);     
+        ctx.ctx.actor = nfsd4_build_namelist;
+        status = iterate_dir(nn->rec_file, &ctx.ctx);
         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
-        while (!list_empty(&names)) {
+        while (!list_empty(&ctx.names)) {
                 struct name_list *entry;
-                entry = list_entry(names.next, struct name_list, list);
+                entry = list_entry(ctx.names.next, struct name_list, list);
                 if (!status) {
                         struct dentry *dentry;
                         dentry = lookup_one_len(entry->name, dir, HEXDIR_LEN-1);
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 84ce601d8063..f939ba9bf8e8 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1912,6 +1912,7 @@ struct buffered_dirent {
 };
 
 struct readdir_data {
+        struct dir_context ctx;
         char            *dirent;
         size_t          used;
         int             full;
@@ -1949,6 +1950,7 @@ static __be32 nfsd_buffered_readdir(struct file *file, filldir_t func,
         int size;
         loff_t offset;
 
+        buf.ctx.actor = nfsd_buffered_filldir;
         buf.dirent = (void *)__get_free_page(GFP_KERNEL);
         if (!buf.dirent)
                 return nfserrno(-ENOMEM);
@@ -1963,7 +1965,7 @@ static __be32 nfsd_buffered_readdir(struct file *file, filldir_t func,
                 buf.used = 0;
                 buf.full = 0;
 
-                host_err = vfs_readdir(file, nfsd_buffered_filldir, &buf);
+                host_err = iterate_dir(file, &buf.ctx);
                 if (buf.full)
                         host_err = 0;
 
diff --git a/fs/readdir.c b/fs/readdir.c
index fee38e04fae4..5b620a2b45e6 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c
@@ -20,7 +20,7 @@
 
 #include <asm/uaccess.h>
 
-int vfs_readdir(struct file *file, filldir_t filler, void *buf)
+int iterate_dir(struct file *file, struct dir_context *ctx)
 {
         struct inode *inode = file_inode(file);
         int res = -ENOTDIR;
@@ -37,15 +37,14 @@ int vfs_readdir(struct file *file, filldir_t filler, void *buf)
 
         res = -ENOENT;
         if (!IS_DEADDIR(inode)) {
-                res = file->f_op->readdir(file, buf, filler);
+                res = file->f_op->readdir(file, ctx, ctx->actor);
                 file_accessed(file);
         }
         mutex_unlock(&inode->i_mutex);
 out:
         return res;
 }
-
-EXPORT_SYMBOL(vfs_readdir);
+EXPORT_SYMBOL(iterate_dir);
 
 /*
  * Traditional linux readdir() handling..
@@ -66,6 +65,7 @@ struct old_linux_dirent {
 };
 
 struct readdir_callback {
+        struct dir_context ctx;
         struct old_linux_dirent __user * dirent;
         int result;
 };
@@ -73,7 +73,7 @@ struct readdir_callback {
 static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset,
                       u64 ino, unsigned int d_type)
 {
-        struct readdir_callback * buf = (struct readdir_callback *) __buf;
+        struct readdir_callback *buf = (struct readdir_callback *) __buf;
         struct old_linux_dirent __user * dirent;
         unsigned long d_ino;
 
@@ -112,10 +112,11 @@ SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
         if (!f.file)
                 return -EBADF;
 
+        buf.ctx.actor = fillonedir;
         buf.result = 0;
         buf.dirent = dirent;
 
-        error = vfs_readdir(f.file, fillonedir, &buf);
+        error = iterate_dir(f.file, &buf.ctx);
         if (buf.result)
                 error = buf.result;
 
@@ -137,6 +138,7 @@ struct linux_dirent {
 };
 
 struct getdents_callback {
+        struct dir_context ctx;
         struct linux_dirent __user * current_dir;
         struct linux_dirent __user * previous;
         int count;
@@ -205,8 +207,9 @@ SYSCALL_DEFINE3(getdents, unsigned int, fd,
         buf.previous = NULL;
         buf.count = count;
         buf.error = 0;
+        buf.ctx.actor = filldir;
 
-        error = vfs_readdir(f.file, filldir, &buf);
+        error = iterate_dir(f.file, &buf.ctx);
         if (error >= 0)
                 error = buf.error;
         lastdirent = buf.previous;
@@ -221,6 +224,7 @@ SYSCALL_DEFINE3(getdents, unsigned int, fd,
 }
 
 struct getdents_callback64 {
+        struct dir_context ctx;
         struct linux_dirent64 __user * current_dir;
         struct linux_dirent64 __user * previous;
         int count;
@@ -285,8 +289,9 @@ SYSCALL_DEFINE3(getdents64, unsigned int, fd,
         buf.previous = NULL;
         buf.count = count;
         buf.error = 0;
+        buf.ctx.actor = filldir64;
 
-        error = vfs_readdir(f.file, filldir64, &buf);
+        error = iterate_dir(f.file, &buf.ctx);
         if (error >= 0)
                 error = buf.error;
         lastdirent = buf.previous;