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[readdir] introduce ->iterate(), ctx->pos, dir_emit()

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New method - ->iterate(file, ctx).  That's the replacement for ->readdir();
it takes callback from ctx->actor, uses ctx->pos instead of file->f_pos and
calls dir_emit(ctx, ...) instead of filldir(data, ...).  It does *not*
update file->f_pos (or look at it, for that matter); iterate_dir() does the
update.

Note that dir_emit() takes the offset from ctx->pos (and eventually
filldir_t will lose that argument).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
2013-05-15 18:49:12 -04:00
parent 5c0ba4e076
commit bb6f619b3a
7 changed files with 47 additions and 18 deletions
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15
fs/readdir.c
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@@ -24,7 +24,7 @@ int iterate_dir(struct file *file, struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
int res = -ENOTDIR;
if (!file->f_op || !file->f_op->readdir)
if (!file->f_op || (!file->f_op->readdir && !file->f_op->iterate))
goto out;
res = security_file_permission(file, MAY_READ);
@@ -37,7 +37,14 @@ int iterate_dir(struct file *file, struct dir_context *ctx)
res = -ENOENT;
if (!IS_DEADDIR(inode)) {
res = file->f_op->readdir(file, ctx, ctx->actor);
if (file->f_op->iterate) {
ctx->pos = file->f_pos;
res = file->f_op->iterate(file, ctx);
file->f_pos = ctx->pos;
} else {
res = file->f_op->readdir(file, ctx, ctx->actor);
ctx->pos = file->f_pos;
}
file_accessed(file);
}
mutex_unlock(&inode->i_mutex);
@@ -214,7 +221,7 @@ SYSCALL_DEFINE3(getdents, unsigned int, fd,
error = buf.error;
lastdirent = buf.previous;
if (lastdirent) {
if (put_user(f.file->f_pos, &lastdirent->d_off))
if (put_user(buf.ctx.pos, &lastdirent->d_off))
error = -EFAULT;
else
error = count - buf.count;
@@ -296,7 +303,7 @@ SYSCALL_DEFINE3(getdents64, unsigned int, fd,
error = buf.error;
lastdirent = buf.previous;
if (lastdirent) {
typeof(lastdirent->d_off) d_off = f.file->f_pos;
typeof(lastdirent->d_off) d_off = buf.ctx.pos;
if (__put_user(d_off, &lastdirent->d_off))
error = -EFAULT;
else