summaryrefslogtreecommitdiff
path: root/fs/ceph/dir.c
diff options
context:
space:
mode:
authorYan, Zheng <zyan@redhat.com>2015-06-16 20:48:56 +0800
committerIlya Dryomov <idryomov@gmail.com>2015-06-25 11:49:32 +0300
commitfdd4e15838e59c394a1ec4963b57c22c12608685 (patch)
treeb5486f7b0f12abf9ed670d187f4841dfdb2aa13e /fs/ceph/dir.c
parentb459be739f97e2062b2ba77cfe8ea198dbd58904 (diff)
ceph: rework dcache readdir
Previously our dcache readdir code relies on that child dentries in directory dentry's d_subdir list are sorted by dentry's offset in descending order. When adding dentries to the dcache, if a dentry already exists, our readdir code moves it to head of directory dentry's d_subdir list. This design relies on dcache internals. Al Viro suggests using ncpfs's approach: keeping array of pointers to dentries in page cache of directory inode. the validity of those pointers are presented by directory inode's complete and ordered flags. When a dentry gets pruned, we clear directory inode's complete flag in the d_prune() callback. Before moving a dentry to other directory, we clear the ordered flag for both old and new directory. Signed-off-by: Yan, Zheng <zyan@redhat.com>
Diffstat (limited to 'fs/ceph/dir.c')
-rw-r--r--fs/ceph/dir.c313
1 files changed, 161 insertions, 152 deletions
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index b99f2ff8189d..9314b4ea2375 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -107,6 +107,27 @@ static int fpos_cmp(loff_t l, loff_t r)
}
/*
+ * make note of the last dentry we read, so we can
+ * continue at the same lexicographical point,
+ * regardless of what dir changes take place on the
+ * server.
+ */
+static int note_last_dentry(struct ceph_file_info *fi, const char *name,
+ int len, unsigned next_offset)
+{
+ char *buf = kmalloc(len+1, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+ kfree(fi->last_name);
+ fi->last_name = buf;
+ memcpy(fi->last_name, name, len);
+ fi->last_name[len] = 0;
+ fi->next_offset = next_offset;
+ dout("note_last_dentry '%s'\n", fi->last_name);
+ return 0;
+}
+
+/*
* When possible, we try to satisfy a readdir by peeking at the
* dcache. We make this work by carefully ordering dentries on
* d_child when we initially get results back from the MDS, and
@@ -123,123 +144,113 @@ static int __dcache_readdir(struct file *file, struct dir_context *ctx,
struct ceph_file_info *fi = file->private_data;
struct dentry *parent = file->f_path.dentry;
struct inode *dir = d_inode(parent);
- struct list_head *p;
- struct dentry *dentry, *last;
+ struct dentry *dentry, *last = NULL;
struct ceph_dentry_info *di;
+ unsigned nsize = PAGE_CACHE_SIZE / sizeof(struct dentry *);
int err = 0;
+ loff_t ptr_pos = 0;
+ struct ceph_readdir_cache_control cache_ctl = {};
- /* claim ref on last dentry we returned */
- last = fi->dentry;
- fi->dentry = NULL;
-
- dout("__dcache_readdir %p v%u at %llu (last %p)\n",
- dir, shared_gen, ctx->pos, last);
-
- spin_lock(&parent->d_lock);
+ dout("__dcache_readdir %p v%u at %llu\n", dir, shared_gen, ctx->pos);
- /* start at beginning? */
- if (ctx->pos == 2 || last == NULL ||
- fpos_cmp(ctx->pos, ceph_dentry(last)->offset) < 0) {
- if (list_empty(&parent->d_subdirs))
- goto out_unlock;
- p = parent->d_subdirs.prev;
- dout(" initial p %p/%p\n", p->prev, p->next);
- } else {
- p = last->d_child.prev;
+ /* we can calculate cache index for the first dirfrag */
+ if (ceph_frag_is_leftmost(fpos_frag(ctx->pos))) {
+ cache_ctl.index = fpos_off(ctx->pos) - 2;
+ BUG_ON(cache_ctl.index < 0);
+ ptr_pos = cache_ctl.index * sizeof(struct dentry *);
}
-more:
- dentry = list_entry(p, struct dentry, d_child);
- di = ceph_dentry(dentry);
- while (1) {
- dout(" p %p/%p %s d_subdirs %p/%p\n", p->prev, p->next,
- d_unhashed(dentry) ? "!hashed" : "hashed",
- parent->d_subdirs.prev, parent->d_subdirs.next);
- if (p == &parent->d_subdirs) {
+ while (true) {
+ pgoff_t pgoff;
+ bool emit_dentry;
+
+ if (ptr_pos >= i_size_read(dir)) {
fi->flags |= CEPH_F_ATEND;
- goto out_unlock;
+ err = 0;
+ break;
}
- spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
+
+ err = -EAGAIN;
+ pgoff = ptr_pos >> PAGE_CACHE_SHIFT;
+ if (!cache_ctl.page || pgoff != page_index(cache_ctl.page)) {
+ ceph_readdir_cache_release(&cache_ctl);
+ cache_ctl.page = find_lock_page(&dir->i_data, pgoff);
+ if (!cache_ctl.page) {
+ dout(" page %lu not found\n", pgoff);
+ break;
+ }
+ /* reading/filling the cache are serialized by
+ * i_mutex, no need to use page lock */
+ unlock_page(cache_ctl.page);
+ cache_ctl.dentries = kmap(cache_ctl.page);
+ }
+
+ rcu_read_lock();
+ spin_lock(&parent->d_lock);
+ /* check i_size again here, because empty directory can be
+ * marked as complete while not holding the i_mutex. */
+ if (ceph_dir_is_complete_ordered(dir) &&
+ ptr_pos < i_size_read(dir))
+ dentry = cache_ctl.dentries[cache_ctl.index % nsize];
+ else
+ dentry = NULL;
+ spin_unlock(&parent->d_lock);
+ if (dentry && !lockref_get_not_dead(&dentry->d_lockref))
+ dentry = NULL;
+ rcu_read_unlock();
+ if (!dentry)
+ break;
+
+ emit_dentry = false;
+ di = ceph_dentry(dentry);
+ spin_lock(&dentry->d_lock);
if (di->lease_shared_gen == shared_gen &&
- !d_unhashed(dentry) && d_really_is_positive(dentry) &&
+ d_really_is_positive(dentry) &&
ceph_snap(d_inode(dentry)) != CEPH_SNAPDIR &&
ceph_ino(d_inode(dentry)) != CEPH_INO_CEPH &&
- fpos_cmp(ctx->pos, di->offset) <= 0)
- break;
- dout(" skipping %p %pd at %llu (%llu)%s%s\n", dentry,
- dentry, di->offset,
- ctx->pos, d_unhashed(dentry) ? " unhashed" : "",
- !d_inode(dentry) ? " null" : "");
+ fpos_cmp(ctx->pos, di->offset) <= 0) {
+ emit_dentry = true;
+ }
spin_unlock(&dentry->d_lock);
- p = p->prev;
- dentry = list_entry(p, struct dentry, d_child);
- di = ceph_dentry(dentry);
- }
-
- dget_dlock(dentry);
- spin_unlock(&dentry->d_lock);
- spin_unlock(&parent->d_lock);
- /* make sure a dentry wasn't dropped while we didn't have parent lock */
- if (!ceph_dir_is_complete_ordered(dir)) {
- dout(" lost dir complete on %p; falling back to mds\n", dir);
- dput(dentry);
- err = -EAGAIN;
- goto out;
- }
+ if (emit_dentry) {
+ dout(" %llu (%llu) dentry %p %pd %p\n", di->offset, ctx->pos,
+ dentry, dentry, d_inode(dentry));
+ ctx->pos = di->offset;
+ if (!dir_emit(ctx, dentry->d_name.name,
+ dentry->d_name.len,
+ ceph_translate_ino(dentry->d_sb,
+ d_inode(dentry)->i_ino),
+ d_inode(dentry)->i_mode >> 12)) {
+ dput(dentry);
+ err = 0;
+ break;
+ }
+ ctx->pos++;
- dout(" %llu (%llu) dentry %p %pd %p\n", di->offset, ctx->pos,
- dentry, dentry, d_inode(dentry));
- if (!dir_emit(ctx, dentry->d_name.name,
- dentry->d_name.len,
- ceph_translate_ino(dentry->d_sb, d_inode(dentry)->i_ino),
- d_inode(dentry)->i_mode >> 12)) {
- if (last) {
- /* remember our position */
- fi->dentry = last;
- fi->next_offset = fpos_off(di->offset);
+ if (last)
+ dput(last);
+ last = dentry;
+ } else {
+ dput(dentry);
}
- dput(dentry);
- return 0;
- }
-
- ctx->pos = di->offset + 1;
-
- if (last)
- dput(last);
- last = dentry;
-
- spin_lock(&parent->d_lock);
- p = p->prev; /* advance to next dentry */
- goto more;
-out_unlock:
- spin_unlock(&parent->d_lock);
-out:
- if (last)
+ cache_ctl.index++;
+ ptr_pos += sizeof(struct dentry *);
+ }
+ ceph_readdir_cache_release(&cache_ctl);
+ if (last) {
+ int ret;
+ di = ceph_dentry(last);
+ ret = note_last_dentry(fi, last->d_name.name, last->d_name.len,
+ fpos_off(di->offset) + 1);
+ if (ret < 0)
+ err = ret;
dput(last);
+ }
return err;
}
-/*
- * make note of the last dentry we read, so we can
- * continue at the same lexicographical point,
- * regardless of what dir changes take place on the
- * server.
- */
-static int note_last_dentry(struct ceph_file_info *fi, const char *name,
- int len)
-{
- kfree(fi->last_name);
- fi->last_name = kmalloc(len+1, GFP_KERNEL);
- if (!fi->last_name)
- return -ENOMEM;
- memcpy(fi->last_name, name, len);
- fi->last_name[len] = 0;
- dout("note_last_dentry '%s'\n", fi->last_name);
- return 0;
-}
-
static int ceph_readdir(struct file *file, struct dir_context *ctx)
{
struct ceph_file_info *fi = file->private_data;
@@ -280,8 +291,7 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
/* can we use the dcache? */
spin_lock(&ci->i_ceph_lock);
- if ((ctx->pos == 2 || fi->dentry) &&
- ceph_test_mount_opt(fsc, DCACHE) &&
+ if (ceph_test_mount_opt(fsc, DCACHE) &&
!ceph_test_mount_opt(fsc, NOASYNCREADDIR) &&
ceph_snap(inode) != CEPH_SNAPDIR &&
__ceph_dir_is_complete_ordered(ci) &&
@@ -296,24 +306,8 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
} else {
spin_unlock(&ci->i_ceph_lock);
}
- if (fi->dentry) {
- err = note_last_dentry(fi, fi->dentry->d_name.name,
- fi->dentry->d_name.len);
- if (err)
- return err;
- dput(fi->dentry);
- fi->dentry = NULL;
- }
/* proceed with a normal readdir */
-
- if (ctx->pos == 2) {
- /* note dir version at start of readdir so we can tell
- * if any dentries get dropped */
- fi->dir_release_count = atomic_read(&ci->i_release_count);
- fi->dir_ordered_count = ci->i_ordered_count;
- }
-
more:
/* do we have the correct frag content buffered? */
if (fi->frag != frag || fi->last_readdir == NULL) {
@@ -348,6 +342,9 @@ more:
return -ENOMEM;
}
}
+ req->r_dir_release_cnt = fi->dir_release_count;
+ req->r_dir_ordered_cnt = fi->dir_ordered_count;
+ req->r_readdir_cache_idx = fi->readdir_cache_idx;
req->r_readdir_offset = fi->next_offset;
req->r_args.readdir.frag = cpu_to_le32(frag);
@@ -364,26 +361,38 @@ more:
(int)req->r_reply_info.dir_end,
(int)req->r_reply_info.dir_complete);
- if (!req->r_did_prepopulate) {
- dout("readdir !did_prepopulate");
- /* preclude from marking dir complete */
- fi->dir_release_count--;
- }
/* note next offset and last dentry name */
rinfo = &req->r_reply_info;
if (le32_to_cpu(rinfo->dir_dir->frag) != frag) {
frag = le32_to_cpu(rinfo->dir_dir->frag);
- if (ceph_frag_is_leftmost(frag))
- fi->next_offset = 2;
- else
- fi->next_offset = 0;
- off = fi->next_offset;
+ off = req->r_readdir_offset;
+ fi->next_offset = off;
}
+
fi->frag = frag;
fi->offset = fi->next_offset;
fi->last_readdir = req;
+ if (req->r_did_prepopulate) {
+ fi->readdir_cache_idx = req->r_readdir_cache_idx;
+ if (fi->readdir_cache_idx < 0) {
+ /* preclude from marking dir ordered */
+ fi->dir_ordered_count = 0;
+ } else if (ceph_frag_is_leftmost(frag) && off == 2) {
+ /* note dir version at start of readdir so
+ * we can tell if any dentries get dropped */
+ fi->dir_release_count = req->r_dir_release_cnt;
+ fi->dir_ordered_count = req->r_dir_ordered_cnt;
+ }
+ } else {
+ dout("readdir !did_prepopulate");
+ /* disable readdir cache */
+ fi->readdir_cache_idx = -1;
+ /* preclude from marking dir complete */
+ fi->dir_release_count = 0;
+ }
+
if (req->r_reply_info.dir_end) {
kfree(fi->last_name);
fi->last_name = NULL;
@@ -394,10 +403,10 @@ more:
} else {
err = note_last_dentry(fi,
rinfo->dir_dname[rinfo->dir_nr-1],
- rinfo->dir_dname_len[rinfo->dir_nr-1]);
+ rinfo->dir_dname_len[rinfo->dir_nr-1],
+ fi->next_offset + rinfo->dir_nr);
if (err)
return err;
- fi->next_offset += rinfo->dir_nr;
}
}
@@ -453,16 +462,22 @@ more:
* were released during the whole readdir, and we should have
* the complete dir contents in our cache.
*/
- spin_lock(&ci->i_ceph_lock);
- if (atomic_read(&ci->i_release_count) == fi->dir_release_count) {
- if (ci->i_ordered_count == fi->dir_ordered_count)
+ if (atomic64_read(&ci->i_release_count) == fi->dir_release_count) {
+ spin_lock(&ci->i_ceph_lock);
+ if (fi->dir_ordered_count == atomic64_read(&ci->i_ordered_count)) {
dout(" marking %p complete and ordered\n", inode);
- else
+ /* use i_size to track number of entries in
+ * readdir cache */
+ BUG_ON(fi->readdir_cache_idx < 0);
+ i_size_write(inode, fi->readdir_cache_idx *
+ sizeof(struct dentry*));
+ } else {
dout(" marking %p complete\n", inode);
+ }
__ceph_dir_set_complete(ci, fi->dir_release_count,
fi->dir_ordered_count);
+ spin_unlock(&ci->i_ceph_lock);
}
- spin_unlock(&ci->i_ceph_lock);
dout("readdir %p file %p done.\n", inode, file);
return 0;
@@ -476,14 +491,12 @@ static void reset_readdir(struct ceph_file_info *fi, unsigned frag)
}
kfree(fi->last_name);
fi->last_name = NULL;
+ fi->dir_release_count = 0;
+ fi->readdir_cache_idx = -1;
if (ceph_frag_is_leftmost(frag))
fi->next_offset = 2; /* compensate for . and .. */
else
fi->next_offset = 0;
- if (fi->dentry) {
- dput(fi->dentry);
- fi->dentry = NULL;
- }
fi->flags &= ~CEPH_F_ATEND;
}
@@ -497,13 +510,12 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
mutex_lock(&inode->i_mutex);
retval = -EINVAL;
switch (whence) {
- case SEEK_END:
- offset += inode->i_size + 2; /* FIXME */
- break;
case SEEK_CUR:
offset += file->f_pos;
case SEEK_SET:
break;
+ case SEEK_END:
+ retval = -EOPNOTSUPP;
default:
goto out;
}
@@ -516,20 +528,18 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
}
retval = offset;
- /*
- * discard buffered readdir content on seekdir(0), or
- * seek to new frag, or seek prior to current chunk.
- */
if (offset == 0 ||
fpos_frag(offset) != fi->frag ||
fpos_off(offset) < fi->offset) {
+ /* discard buffered readdir content on seekdir(0), or
+ * seek to new frag, or seek prior to current chunk */
dout("dir_llseek dropping %p content\n", file);
reset_readdir(fi, fpos_frag(offset));
+ } else if (fpos_cmp(offset, old_offset) > 0) {
+ /* reset dir_release_count if we did a forward seek */
+ fi->dir_release_count = 0;
+ fi->readdir_cache_idx = -1;
}
-
- /* bump dir_release_count if we did a forward seek */
- if (fpos_cmp(offset, old_offset) > 0)
- fi->dir_release_count--;
}
out:
mutex_unlock(&inode->i_mutex);
@@ -985,16 +995,15 @@ static int ceph_rename(struct inode *old_dir, struct dentry *old_dentry,
* to do it here.
*/
+ /* d_move screws up sibling dentries' offsets */
+ ceph_dir_clear_complete(old_dir);
+ ceph_dir_clear_complete(new_dir);
+
d_move(old_dentry, new_dentry);
/* ensure target dentry is invalidated, despite
rehashing bug in vfs_rename_dir */
ceph_invalidate_dentry_lease(new_dentry);
-
- /* d_move screws up sibling dentries' offsets */
- ceph_dir_clear_complete(old_dir);
- ceph_dir_clear_complete(new_dir);
-
}
ceph_mdsc_put_request(req);
return err;