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fuse-overlayfs: use renameat2(RENAME_WHITEOUT) when possible

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Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
This commit is contained in:
Giuseppe Scrivano 2018-07-11 18:29:48 +02:00
parent 81c939f350
commit 616119093a
No known key found for this signature in database
GPG Key ID: E4730F97F60286ED
1 changed files with 61 additions and 20 deletions
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81
main.c
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@ -50,6 +50,8 @@
#include <sys/xattr.h>
#include <linux/fs.h>
#ifndef RENAME_EXCHANGE
# define RENAME_EXCHANGE (1 << 1)
# define RENAME_NOREPLACE (1 << 2)
@ -347,12 +349,14 @@ hide_node (struct ovl_data *lo, struct ovl_node *node, bool unlink_src)
return -1;
}
assert (node->layer == get_upper_layer (lo));
/* Might be leftover from a previous run. */
unlinkat (lo->workdir_fd, newpath, 0);
if (unlink_src)
if (! unlink_src)
{
if (renameat (node_dirfd (node), node->path, lo->workdir_fd, newpath) < 0)
if (linkat (node_dirfd (node), node->path, lo->workdir_fd, newpath, 0) < 0)
{
free (newpath);
return -1;
@ -360,10 +364,20 @@ hide_node (struct ovl_data *lo, struct ovl_node *node, bool unlink_src)
}
else
{
if (linkat (node_dirfd (node), node->path, lo->workdir_fd, newpath, 0) < 0)
/* If the atomic rename+mknod failed, then fallback into doing it in two steps. */
if (syscall (SYS_renameat2, node_dirfd (node), node->path, lo->workdir_fd,
newpath, RENAME_WHITEOUT) < 0)
{
free (newpath);
return -1;
if (renameat (node_dirfd (node), node->path, lo->workdir_fd, newpath) < 0)
{
free (newpath);
return -1;
}
if (node->parent)
{
if (create_whiteout (lo, node->parent, node->name) < 0)
return -1;
}
}
}
node->hidden_dirfd = lo->workdir_fd;
@ -1631,6 +1645,16 @@ do_rm (fuse_req_t req, fuse_ino_t parent, const char *name, bool dirp)
return;
}
/* If the node is still accessible then be sure we,
can write to it. Fix it to be done when a write is
really done, not now. */
node = get_node_up (lo, node);
if (node == NULL)
{
fuse_reply_err (req, errno);
return;
}
key.name = (char *) name;
rm = hash_delete (pnode->children, &key);
if (rm)
@ -1645,13 +1669,6 @@ do_rm (fuse_req_t req, fuse_ino_t parent, const char *name, bool dirp)
node_free (rm);
}
ret = create_whiteout (lo, pnode, name);
if (ret < 0)
{
fuse_reply_err (req, errno);
return;
}
fuse_reply_err (req, ret);
}
@ -2421,20 +2438,33 @@ ovl_rename (fuse_req_t req, fuse_ino_t parent, const char *name,
rm = NULL;
}
if (rm && hide_node (lo, rm, false) < 0)
goto error;
if (rm)
{
/* If the node is still accessible then be sure we
can write to it. Fix it to be done when a write is
really done, not now. */
rm = get_node_up (lo, rm);
if (rm == NULL)
{
fuse_reply_err (req, errno);
return;
}
if (hide_node (lo, rm, false) < 0)
goto error;
}
}
}
ret = syscall (SYS_renameat2, srcfd, name, destfd, newname, flags);
if (ret < 0)
goto error;
if (flags & RENAME_EXCHANGE)
{
struct ovl_node *rm1, *rm2;
char *tmp;
ret = syscall (SYS_renameat2, srcfd, name, destfd, newname, flags);
if (ret < 0)
goto error;
rm1 = hash_delete (destpnode->children, destnode);
rm2 = hash_delete (pnode->children, node);
@ -2465,8 +2495,19 @@ ovl_rename (fuse_req_t req, fuse_ino_t parent, const char *name,
}
else
{
if (create_whiteout (lo, pnode, name) < 0)
goto error;
/* Try to create the whiteout atomically, if it fails do the
rename+mknod separately. */
ret = syscall (SYS_renameat2, srcfd, name, destfd,
newname, flags|RENAME_WHITEOUT);
if (ret < 0)
{
ret = syscall (SYS_renameat2, srcfd, name, destfd, newname, flags);
if (ret < 0)
goto error;
if (create_whiteout (lo, pnode, name) < 0)
goto error;
}
hash_delete (pnode->children, node);