[RFC PATCH 4/5] Directory seek support
Directory seek support.
Define the seek behaviour on the stored cache of dirents.
Signed-off-by: Bharata B Rao <[EMAIL PROTECTED]>
---
fs/read_write.c | 11 ---
fs/union.c| 171 +-
include/linux/fs.h|8 ++
include/linux/union.h | 25 +++
4 files changed, 205 insertions(+), 10 deletions(-)
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -16,6 +16,7 @@
#include
#include
#include
+#include
#include "read_write.h"
#include
@@ -116,15 +117,7 @@ EXPORT_SYMBOL(default_llseek);
loff_t vfs_llseek(struct file *file, loff_t offset, int origin)
{
- loff_t (*fn)(struct file *, loff_t, int);
-
- fn = no_llseek;
- if (file->f_mode & FMODE_LSEEK) {
- fn = default_llseek;
- if (file->f_op && file->f_op->llseek)
- fn = file->f_op->llseek;
- }
- return fn(file, offset, origin);
+ return do_llseek(file, offset, origin);
}
EXPORT_SYMBOL(vfs_llseek);
--- a/fs/union.c
+++ b/fs/union.c
@@ -614,6 +614,7 @@ static int rdcache_add_entry(struct rdst
this->dtype = d_type;
INIT_LIST_HEAD(>list);
list_add_tail(>list, list);
+ r->cur_dirent = this;
return 0;
}
@@ -636,18 +637,96 @@ static int filldir_union(void *buf, cons
if (rdcache_find_entry(>dirent_cache, name, namlen))
return 0;
- err = cb->filldir(cb->buf, name, namlen, r->cur_off,
+ /* We come here with NULL cb->filldir from lseek path */
+ if (cb->filldir)
+ err = cb->filldir(cb->buf, name, namlen, r->cur_off,
ino, d_type);
if (err >= 0) {
rdcache_add_entry(r, >dirent_cache,
name, namlen, offset, ino, d_type);
r->cur_off = ++r->last_off;
r->nr_dirents++;
+ if (r->cur_off == r->fill_off) {
+ /* We filled up to the required seek offset */
+ r->fill_off = 0;
+ err = -EINVAL;
+ }
}
cb->error = err;
return err;
}
+/*
+ * This is called when current offset in rdcache gets changed and when
+ * we need to change the current underlying directory in the rdstate
+ * to match the current offset.
+ */
+static void update_rdstate(struct file *file)
+{
+ struct rdstate *r = file->f_rdstate;
+ loff_t off = r->cur_off;
+ struct union_mount *um;
+
+ if (!(r->flags & RDSTATE_NEED_UPDATE))
+ return;
+
+ spin_lock(_lock);
+ um = union_lookup(file->f_path.dentry, file->f_path.mnt);
+ spin_unlock(_lock);
+ if (!um)
+ goto out;
+ off -= um->nr_dirents;
+ path_put(>cur_path);
+ r->cur_path = file->f_path;
+ path_get(>cur_path);
+
+ while (off > 0) {
+ spin_lock(_lock);
+ um = union_lookup(r->cur_path.dentry, r->cur_path.mnt);
+ spin_unlock(_lock);
+ if (!um)
+ goto out;
+ off -= um->nr_dirents;
+ path_put(>cur_path);
+ r->cur_path = um->u_next;
+ path_get(>cur_path);
+ }
+out:
+ r->file_off = r->cur_dirent->off;
+}
+
+/*
+ * Returns dirents from rdcache to userspace.
+ */
+static int readdir_rdcache(struct file *file, struct rdcache_callback *cb)
+{
+ struct rdstate *r = cb->rdstate;
+ struct rdcache_entry *tmp = r->cur_dirent;
+ int err = 0;
+
+ BUG_ON(r->cur_off > r->last_off);
+
+ /* If offsets already uptodate, just return */
+ if (likely(r->cur_off == r->last_off))
+ return 0;
+
+ /*
+* return the entries from cur_off till last_off from rdcache to
+* user space.
+*/
+ list_for_each_entry_from(tmp, >dirent_cache, list) {
+ err = cb->filldir(cb->buf, tmp->name.name, tmp->name.len,
+ r->cur_off, tmp->ino, tmp->dtype);
+ r->cur_dirent = tmp;
+ if (err < 0)
+ break;
+ r->cur_off++;
+ r->flags |= RDSTATE_NEED_UPDATE;
+ }
+ update_rdstate(file);
+ return err;
+}
+
/* Called from last fput() */
void put_rdstate(struct rdstate *rdstate)
{
@@ -710,6 +789,10 @@ int readdir_union(struct file *file, voi
cb.rdstate = rdstate;
cb.error = 0;
+ err = readdir_rdcache(file, );
+ if (err)
+ return err;
+
offset = rdstate->file_off;
/* Read from the topmost directory */
@@ -796,6 +879,92 @@ out:
return err;
}
+static void rdcache_rewind(struct file *file, struct rdstate *r, loff_t offset)
+{
+ struct rdcache_entry *tmp = r->cur_dirent;
+
+ list_for_each_entry_reverse_from(tmp, >dirent_cache, list) {
+ if (r->cur_off == offset)
+
[RFC PATCH 4/5] Directory seek support
Directory seek support.
Define the seek behaviour on the stored cache of dirents.
Signed-off-by: Bharata B Rao [EMAIL PROTECTED]
---
fs/read_write.c | 11 ---
fs/union.c| 171 +-
include/linux/fs.h|8 ++
include/linux/union.h | 25 +++
4 files changed, 205 insertions(+), 10 deletions(-)
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -16,6 +16,7 @@
#include linux/syscalls.h
#include linux/pagemap.h
#include linux/splice.h
+#include linux/union.h
#include read_write.h
#include asm/uaccess.h
@@ -116,15 +117,7 @@ EXPORT_SYMBOL(default_llseek);
loff_t vfs_llseek(struct file *file, loff_t offset, int origin)
{
- loff_t (*fn)(struct file *, loff_t, int);
-
- fn = no_llseek;
- if (file-f_mode FMODE_LSEEK) {
- fn = default_llseek;
- if (file-f_op file-f_op-llseek)
- fn = file-f_op-llseek;
- }
- return fn(file, offset, origin);
+ return do_llseek(file, offset, origin);
}
EXPORT_SYMBOL(vfs_llseek);
--- a/fs/union.c
+++ b/fs/union.c
@@ -614,6 +614,7 @@ static int rdcache_add_entry(struct rdst
this-dtype = d_type;
INIT_LIST_HEAD(this-list);
list_add_tail(this-list, list);
+ r-cur_dirent = this;
return 0;
}
@@ -636,18 +637,96 @@ static int filldir_union(void *buf, cons
if (rdcache_find_entry(r-dirent_cache, name, namlen))
return 0;
- err = cb-filldir(cb-buf, name, namlen, r-cur_off,
+ /* We come here with NULL cb-filldir from lseek path */
+ if (cb-filldir)
+ err = cb-filldir(cb-buf, name, namlen, r-cur_off,
ino, d_type);
if (err = 0) {
rdcache_add_entry(r, r-dirent_cache,
name, namlen, offset, ino, d_type);
r-cur_off = ++r-last_off;
r-nr_dirents++;
+ if (r-cur_off == r-fill_off) {
+ /* We filled up to the required seek offset */
+ r-fill_off = 0;
+ err = -EINVAL;
+ }
}
cb-error = err;
return err;
}
+/*
+ * This is called when current offset in rdcache gets changed and when
+ * we need to change the current underlying directory in the rdstate
+ * to match the current offset.
+ */
+static void update_rdstate(struct file *file)
+{
+ struct rdstate *r = file-f_rdstate;
+ loff_t off = r-cur_off;
+ struct union_mount *um;
+
+ if (!(r-flags RDSTATE_NEED_UPDATE))
+ return;
+
+ spin_lock(union_lock);
+ um = union_lookup(file-f_path.dentry, file-f_path.mnt);
+ spin_unlock(union_lock);
+ if (!um)
+ goto out;
+ off -= um-nr_dirents;
+ path_put(r-cur_path);
+ r-cur_path = file-f_path;
+ path_get(r-cur_path);
+
+ while (off 0) {
+ spin_lock(union_lock);
+ um = union_lookup(r-cur_path.dentry, r-cur_path.mnt);
+ spin_unlock(union_lock);
+ if (!um)
+ goto out;
+ off -= um-nr_dirents;
+ path_put(r-cur_path);
+ r-cur_path = um-u_next;
+ path_get(r-cur_path);
+ }
+out:
+ r-file_off = r-cur_dirent-off;
+}
+
+/*
+ * Returns dirents from rdcache to userspace.
+ */
+static int readdir_rdcache(struct file *file, struct rdcache_callback *cb)
+{
+ struct rdstate *r = cb-rdstate;
+ struct rdcache_entry *tmp = r-cur_dirent;
+ int err = 0;
+
+ BUG_ON(r-cur_off r-last_off);
+
+ /* If offsets already uptodate, just return */
+ if (likely(r-cur_off == r-last_off))
+ return 0;
+
+ /*
+* return the entries from cur_off till last_off from rdcache to
+* user space.
+*/
+ list_for_each_entry_from(tmp, r-dirent_cache, list) {
+ err = cb-filldir(cb-buf, tmp-name.name, tmp-name.len,
+ r-cur_off, tmp-ino, tmp-dtype);
+ r-cur_dirent = tmp;
+ if (err 0)
+ break;
+ r-cur_off++;
+ r-flags |= RDSTATE_NEED_UPDATE;
+ }
+ update_rdstate(file);
+ return err;
+}
+
/* Called from last fput() */
void put_rdstate(struct rdstate *rdstate)
{
@@ -710,6 +789,10 @@ int readdir_union(struct file *file, voi
cb.rdstate = rdstate;
cb.error = 0;
+ err = readdir_rdcache(file, cb);
+ if (err)
+ return err;
+
offset = rdstate-file_off;
/* Read from the topmost directory */
@@ -796,6 +879,92 @@ out:
return err;
}
+static void rdcache_rewind(struct file *file, struct rdstate *r, loff_t offset)
+{
+ struct rdcache_entry *tmp = r-cur_dirent;
+
+ list_for_each_entry_reverse_from(tmp, r-dirent_cache, list) {
+
