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ovl: don't use a temp buf for encoding real fh

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We can allocate maximum fh size and encode into it directly.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Amir Goldstein 2019-11-15 13:33:04 +02:00 committed by Miklos Szeredi
parent cbe7fba8ed
commit ec7bbb53d3
1 changed files with 16 additions and 21 deletions
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37
fs/overlayfs/copy_up.c
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@ -227,13 +227,17 @@ int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat)
struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper)
{
struct ovl_fh *fh;
int fh_type, fh_len, dwords;
void *buf;
int fh_type, dwords;
int buflen = MAX_HANDLE_SZ;
uuid_t *uuid = &real->d_sb->s_uuid;
int err;
buf = kmalloc(buflen, GFP_KERNEL);
if (!buf)
/* Make sure the real fid stays 32bit aligned */
BUILD_BUG_ON(OVL_FH_FID_OFFSET % 4);
BUILD_BUG_ON(MAX_HANDLE_SZ + OVL_FH_FID_OFFSET > 255);
fh = kzalloc(buflen + OVL_FH_FID_OFFSET, GFP_KERNEL);
if (!fh)
return ERR_PTR(-ENOMEM);
/*
@ -242,24 +246,14 @@ struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper)
* the price or reconnecting the dentry.
*/
dwords = buflen >> 2;
fh_type = exportfs_encode_fh(real, buf, &dwords, 0);
fh_type = exportfs_encode_fh(real, (void *)fh->fb.fid, &dwords, 0);
buflen = (dwords << 2);
fh = ERR_PTR(-EIO);
err = -EIO;
if (WARN_ON(fh_type < 0) ||
WARN_ON(buflen > MAX_HANDLE_SZ) ||
WARN_ON(fh_type == FILEID_INVALID))
goto out;
/* Make sure the real fid stays 32bit aligned */
BUILD_BUG_ON(OVL_FH_FID_OFFSET % 4);
BUILD_BUG_ON(MAX_HANDLE_SZ + OVL_FH_FID_OFFSET > 255);
fh_len = OVL_FH_FID_OFFSET + buflen;
fh = kzalloc(fh_len, GFP_KERNEL);
if (!fh) {
fh = ERR_PTR(-ENOMEM);
goto out;
}
goto out_err;
fh->fb.version = OVL_FH_VERSION;
fh->fb.magic = OVL_FH_MAGIC;
@ -273,13 +267,14 @@ struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper)
*/
if (is_upper)
fh->fb.flags |= OVL_FH_FLAG_PATH_UPPER;
fh->fb.len = fh_len - OVL_FH_WIRE_OFFSET;
fh->fb.len = sizeof(fh->fb) + buflen;
fh->fb.uuid = *uuid;
memcpy(fh->fb.fid, buf, buflen);
out:
kfree(buf);
return fh;
out_err:
kfree(fh);
return ERR_PTR(err);
}
int ovl_set_origin(struct dentry *dentry, struct dentry *lower,