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ovl: copy up regular file using O_TMPFILE 

In preparation for concurrent copy up, implement copy up
of regular file as O_TMPFILE that is linked to upperdir
instead of a file in workdir that is moved to upperdir.

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 2017-01-17 06:34:55 +02:00 committed by Miklos Szeredi
parent 42f269b925
commit d8514d8edb
1 changed files with 20 additions and 7 deletions
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27
fs/overlayfs/copy_up.c
View File

@ -20,6 +20,7 @@
#include <linux/fdtable.h>
#include <linux/ratelimit.h>
#include "overlayfs.h"
#include "ovl_entry.h"
#define OVL_COPY_UP_CHUNK_SIZE (1 << 20)
@ -233,7 +234,7 @@ int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat)
static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
struct dentry *dentry, struct path *lowerpath,
struct kstat *stat, const char *link,
struct kstat *pstat)
struct kstat *pstat, bool tmpfile)
{
struct inode *wdir = workdir->d_inode;
struct inode *udir = upperdir->d_inode;
@ -263,12 +264,17 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
if (new_creds)
old_creds = override_creds(new_creds);
temp = ovl_lookup_temp(workdir, dentry);
if (tmpfile)
temp = ovl_do_tmpfile(upperdir, stat->mode);
else
temp = ovl_lookup_temp(workdir, dentry);
err = PTR_ERR(temp);
if (IS_ERR(temp))
goto out1;
err = ovl_create_real(wdir, temp, &cattr, NULL, true);
err = 0;
if (!tmpfile)
err = ovl_create_real(wdir, temp, &cattr, NULL, true);
if (new_creds) {
revert_creds(old_creds);
@ -300,11 +306,14 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
if (err)
goto out_cleanup;
err = ovl_do_rename(wdir, temp, udir, upper, 0);
if (tmpfile)
err = ovl_do_link(temp, udir, upper, true);
else
err = ovl_do_rename(wdir, temp, udir, upper, 0);
if (err)
goto out_cleanup;
newdentry = dget(temp);
newdentry = dget(tmpfile ? upper : temp);
ovl_dentry_update(dentry, newdentry);
ovl_inode_update(d_inode(dentry), d_inode(newdentry));
@ -318,7 +327,8 @@ out:
return err;
out_cleanup:
ovl_cleanup(wdir, temp);
if (!tmpfile)
ovl_cleanup(wdir, temp);
goto out2;
}
@ -342,6 +352,9 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
struct dentry *lowerdentry = lowerpath->dentry;
struct dentry *upperdir;
const char *link = NULL;
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
/* Should we copyup with O_TMPFILE or with workdir? */
bool tmpfile = S_ISREG(stat->mode) && ofs->tmpfile;
if (WARN_ON(!workdir))
return -EROFS;
@ -373,7 +386,7 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
}
err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath,
stat, link, &pstat);
stat, link, &pstat, tmpfile);
out_unlock:
unlock_rename(workdir, upperdir);
do_delayed_call(&done);