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authorAmir Goldstein <amir73il@gmail.com>2017-01-17 06:34:57 +0200
committerMiklos Szeredi <mszeredi@redhat.com>2017-02-07 15:47:14 +0100
commit01ad3eb8a07385bc8849f0ee7c800e7c8bd7287e (patch)
treedd56100b213de1a7983f2f1a2597ed169dd31d62 /fs
parent39d3d60a54df05a1a32fa71159d7a26a530dee6c (diff)
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ovl: concurrent copy up of regular files
Now that copy up of regular file is done using O_TMPFILE, we don't need to hold rename_lock throughout copy up. Use the copy up waitqueue to synchronize concurrent copy up of the same file. Different regular files can be copied up concurrently. The upper dir inode_lock is taken instead of rename_lock, because it is needed for lookup and later for linking the temp file, but it is released while copying up data. 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>
Diffstat (limited to 'fs')
-rw-r--r--fs/overlayfs/copy_up.c35
1 files changed, 31 insertions, 4 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 6e39e90b5605..48eb8812ac5b 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -291,7 +291,16 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
BUG_ON(upperpath.dentry != NULL);
upperpath.dentry = temp;
- err = ovl_copy_up_data(lowerpath, &upperpath, stat->size);
+ if (tmpfile) {
+ inode_unlock(udir);
+ err = ovl_copy_up_data(lowerpath, &upperpath,
+ stat->size);
+ inode_lock_nested(udir, I_MUTEX_PARENT);
+ } else {
+ err = ovl_copy_up_data(lowerpath, &upperpath,
+ stat->size);
+ }
+
if (err)
goto out_cleanup;
}
@@ -353,8 +362,6 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *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;
@@ -374,6 +381,25 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
return PTR_ERR(link);
}
+ /* Should we copyup with O_TMPFILE or with workdir? */
+ if (S_ISREG(stat->mode) && ofs->tmpfile) {
+ err = ovl_copy_up_start(dentry);
+ /* err < 0: interrupted, err > 0: raced with another copy-up */
+ if (unlikely(err)) {
+ pr_debug("ovl_copy_up_start(%pd2) = %i\n", dentry, err);
+ if (err > 0)
+ err = 0;
+ goto out_done;
+ }
+
+ inode_lock_nested(upperdir->d_inode, I_MUTEX_PARENT);
+ err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath,
+ stat, link, &pstat, true);
+ inode_unlock(upperdir->d_inode);
+ ovl_copy_up_end(dentry);
+ goto out_done;
+ }
+
err = -EIO;
if (lock_rename(workdir, upperdir) != NULL) {
pr_err("overlayfs: failed to lock workdir+upperdir\n");
@@ -386,9 +412,10 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
}
err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath,
- stat, link, &pstat, tmpfile);
+ stat, link, &pstat, false);
out_unlock:
unlock_rename(workdir, upperdir);
+out_done:
do_delayed_call(&done);
return err;