On 3/1/22 9:31 PM, Jeff Layton wrote:
On Tue, 2022-03-01 at 19:30 +0800, xiubli@xxxxxxxxxx wrote:From: Xiubo Li <xiubli@xxxxxxxxxx> Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx> --- fs/ceph/dir.c | 66 +++++++++++++++++++++----------------------- fs/ceph/inode.c | 15 ++++++++++ fs/ceph/mds_client.h | 1 + 3 files changed, 47 insertions(+), 35 deletions(-) diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c index 6be0c1f793c2..e3917b4426e8 100644 --- a/fs/ceph/dir.c +++ b/fs/ceph/dir.c @@ -316,8 +316,7 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx) int err; unsigned frag = -1; struct ceph_mds_reply_info_parsed *rinfo; - struct fscrypt_str tname = FSTR_INIT(NULL, 0); - struct fscrypt_str oname = FSTR_INIT(NULL, 0); + char *dentry_name = NULL;dout("readdir %p file %p pos %llx\n", inode, file, ctx->pos);if (dfi->file_info.flags & CEPH_F_ATEND) @@ -345,10 +344,6 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx) ctx->pos = 2; }- err = fscrypt_prepare_readdir(inode);- if (err) - goto out; -Why are you removing this? This is what ensures that the key is loaded if we're going to need it.
Since the dentry names are already decrypted in ceph_readdir_prepopulate(), and this patch is trying to avoid do the same thing again here after that.
Because in ceph_readdir() this isn't needed any more. And in other places such as build path it will do it when needed.
spin_lock(&ci->i_ceph_lock); /* request Fx cap. if have Fx, we don't need to release Fs cap * for later create/unlink. */ @@ -369,14 +364,6 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx) spin_unlock(&ci->i_ceph_lock); }- err = ceph_fname_alloc_buffer(inode, &tname);- if (err < 0) - goto out; - - err = ceph_fname_alloc_buffer(inode, &oname); - if (err < 0) - goto out; - /* proceed with a normal readdir */ more: /* do we have the correct frag content buffered? */ @@ -525,40 +512,49 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx) } } } + + dentry_name = kmalloc(280, GFP_KERNEL); + if (!dentry_name) { + err = -ENOMEM; + goto out; + } +Woah, what's up with the bare "280" here?
The long snap name in format of "_${ENCRYPTED-SNAP-NAME}_${INO}", the max length will be 1 +256 + 16.
for (; i < rinfo->dir_nr; i++) { struct ceph_mds_reply_dir_entry *rde = rinfo->dir_entries + i; - struct ceph_fname fname = { .dir = inode, - .name = rde->name, - .name_len = rde->name_len, - .ctext = rde->altname, - .ctext_len = rde->altname_len }; - u32 olen = oname.len; - - err = ceph_fname_to_usr(&fname, &tname, &oname, NULL); - if (err) { - pr_err("%s unable to decode %.*s, got %d\n", __func__, - rde->name_len, rde->name, err); - goto out; - }I may be missing something, but if you rip this out, where does the decryption happen?
In ceph_readdir_prepopulate(), and it will set the rde->dentry, and here we can get the name from the dentry directly instead of decrypt it again.
+ struct dentry *dn = rde->dentry; + int name_len;BUG_ON(rde->offset < ctx->pos);BUG_ON(!rde->inode.in); + BUG_ON(!rde->dentry);ctx->pos = rde->offset;- dout("readdir (%d/%d) -> %llx '%.*s' %p\n", - i, rinfo->dir_nr, ctx->pos, - rde->name_len, rde->name, &rde->inode.in);- if (!dir_emit(ctx, oname.name, oname.len,+ spin_lock(&dn->d_lock); + memcpy(dentry_name, dn->d_name.name, dn->d_name.len); + name_len = dn->d_name.len; + spin_unlock(&dn->d_lock); + + dentry_name[name_len] = '\0'; + dout("readdir (%d/%d) -> %llx '%s' %p\n", + i, rinfo->dir_nr, ctx->pos, dentry_name, &rde->inode.in); + + dput(dn); + rde->dentry = NULL; + + if (!dir_emit(ctx, dentry_name, name_len, ceph_present_ino(inode->i_sb, le64_to_cpu(rde->inode.in->ino)), le32_to_cpu(rde->inode.in->mode) >> 12)) { dout("filldir stopping us...\n"); err = 0; + for (; i < rinfo->dir_nr; i++) { + rde = rinfo->dir_entries + i; + dput(rde->dentry); + rde->dentry = NULL; + } goto out; }- /* Reset the lengths to their original allocated vals */- oname.len = olen; ctx->pos++; }@@ -616,8 +612,8 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)err = 0; dout("readdir %p file %p done.\n", inode, file); out: - ceph_fname_free_buffer(inode, &tname); - ceph_fname_free_buffer(inode, &oname); + if (dentry_name) + kfree(dentry_name); return err; }diff --git a/fs/ceph/inode.c b/fs/ceph/inode.cindex 2bc2f02b84e8..877e699fe43b 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -1903,6 +1903,7 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req, goto out; }+ rde->dentry = NULL;dname.name = oname.name; dname.len = oname.len; dname.hash = full_name_hash(parent, dname.name, dname.len); @@ -1963,6 +1964,12 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req, goto retry_lookup; }+ /*+ * ceph_readdir will use the dentry to get the name + * to avoid doing the dencrypt again there. + */ + rde->dentry = dget(dn); + /* inode */ if (d_really_is_positive(dn)) { in = d_inode(dn); @@ -2025,6 +2032,14 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req, dput(dn); } out: + if (err) { + for (; i >= 0; i--) { + struct ceph_mds_reply_dir_entry *rde; + + rde = rinfo->dir_entries + i; + dput(rde->dentry); + } + } if (err == 0 && skipped == 0) { set_bit(CEPH_MDS_R_DID_PREPOPULATE, &req->r_req_flags); req->r_readdir_cache_idx = cache_ctl.index; diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h index 0dfe24f94567..663d7754d57d 100644 --- a/fs/ceph/mds_client.h +++ b/fs/ceph/mds_client.h @@ -96,6 +96,7 @@ struct ceph_mds_reply_info_in { };struct ceph_mds_reply_dir_entry {+ struct dentry *dentry; char *name; u8 *altname; u32 name_len;NAK on this patch as it is...
