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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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2
arch/parisc/hpux/fs.c
View File

@ -129,7 +129,7 @@ int hpux_getdents(unsigned int fd, struct hpux_dirent __user *dirent, unsigned i
error = buf.error;
lastdirent = buf.previous;
if (lastdirent) {
if (put_user(arg.file->f_pos, &lastdirent->d_off))
if (put_user(buf.ctx.pos, &lastdirent->d_off))
error = -EFAULT;
else
error = count - buf.count;

19
fs/coda/dir.c
View File

@ -391,8 +391,7 @@ static int coda_readdir(struct file *coda_file, void *buf, filldir_t filldir)
if (!host_file->f_op)
return -ENOTDIR;
if (host_file->f_op->readdir)
{
if (host_file->f_op->readdir) {
/* potemkin case: we were handed a directory inode.
* We can't use vfs_readdir because we have to keep the file
* position in sync between the coda_file and the host_file.
@ -410,8 +409,20 @@ static int coda_readdir(struct file *coda_file, void *buf, filldir_t filldir)
coda_file->f_pos = host_file->f_pos;
mutex_unlock(&host_inode->i_mutex);
}
else /* Venus: we must read Venus dirents from a file */
} else if (host_file->f_op->iterate) {
struct inode *host_inode = file_inode(host_file);
struct dir_context *ctx = buf;
mutex_lock(&host_inode->i_mutex);
ret = -ENOENT;
if (!IS_DEADDIR(host_inode)) {
ret = host_file->f_op->iterate(host_file, ctx);
file_accessed(host_file);
}
mutex_unlock(&host_inode->i_mutex);
coda_file->f_pos = ctx->pos;
} else /* Venus: we must read Venus dirents from a file */
ret = coda_venus_readdir(coda_file, buf, filldir);
return ret;

4
fs/compat.c
View File

@ -975,7 +975,7 @@ asmlinkage long compat_sys_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;
@ -1062,7 +1062,7 @@ asmlinkage long compat_sys_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_unaligned(d_off, &lastdirent->d_off))
error = -EFAULT;
else

2
fs/exportfs/expfs.c
View File

@ -272,7 +272,7 @@ static int get_name(const struct path *path, char *name, struct dentry *child)
goto out;
error = -EINVAL;
if (!file->f_op->readdir)
if (!file->f_op->readdir && !file->f_op->iterate)
goto out_close;
buffer.name = name;

14
fs/nfsd/nfs4recover.c
View File

@ -240,11 +240,16 @@ struct name_list {
struct list_head list;
};
struct nfs4_dir_ctx {
struct dir_context ctx;
struct list_head names;
};
static int
nfsd4_build_namelist(void *arg, const char *name, int namlen,
loff_t offset, u64 ino, unsigned int d_type)
{
struct list_head *names = arg;
struct nfs4_dir_ctx *ctx = arg;
struct name_list *entry;
if (namlen != HEXDIR_LEN - 1)
@ -254,7 +259,7 @@ nfsd4_build_namelist(void *arg, const char *name, int namlen,
return -ENOMEM;
memcpy(entry->name, name, HEXDIR_LEN - 1);
entry->name[HEXDIR_LEN - 1] = '\0';
list_add(&entry->list, names);
list_add(&entry->list, &ctx->names);
return 0;
}
@ -263,10 +268,7 @@ 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;
struct {
struct dir_context ctx;
struct list_head names;
} ctx;
struct nfs4_dir_ctx ctx;
int status;
status = nfs4_save_creds(&original_cred);

15
fs/readdir.c
View File

@ -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

9
include/linux/fs.h
View File

@ -1508,7 +1508,15 @@ int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);
typedef int (*filldir_t)(void *, const char *, int, loff_t, u64, unsigned);
struct dir_context {
filldir_t actor;
loff_t pos;
};
static inline bool dir_emit(struct dir_context *ctx,
const char *name, int namelen,
u64 ino, unsigned type)
{
return ctx->actor(ctx, name, namelen, ctx->pos, ino, type) == 0;
}
struct block_device_operations;
/* These macros are for out of kernel modules to test that
@ -1525,6 +1533,7 @@ struct file_operations {
ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
int (*readdir) (struct file *, void *, filldir_t);
int (*iterate) (struct file *, struct dir_context *);
unsigned int (*poll) (struct file *, struct poll_table_struct *);
long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
long (*compat_ioctl) (struct file *, unsigned int, unsigned long);