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ovl: split out ovl_get_lowerstack() from ovl_fill_super() 

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Miklos Szeredi 2017-11-09 10:23:28 +01:00
parent 87ad447a9d
commit 53dbb0b478
1 changed files with 72 additions and 50 deletions
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122
fs/overlayfs/super.c
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@ -895,6 +895,75 @@ static int ovl_get_workpath(struct ovl_fs *ufs, struct path *upperpath,
return err;
}
static int ovl_get_lowerstack(struct super_block *sb, struct ovl_fs *ufs,
struct path **stackp, unsigned int *stacklenp)
{
int err;
char *lowertmp, *lower;
struct path *stack;
unsigned int stacklen, numlower, i;
bool remote = false;
err = -ENOMEM;
lowertmp = kstrdup(ufs->config.lowerdir, GFP_KERNEL);
if (!lowertmp)
goto out;
err = -EINVAL;
stacklen = ovl_split_lowerdirs(lowertmp);
if (stacklen > OVL_MAX_STACK) {
pr_err("overlayfs: too many lower directories, limit is %d\n",
OVL_MAX_STACK);
goto out;
} else if (!ufs->config.upperdir && stacklen == 1) {
pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n");
goto out;
}
err = -ENOMEM;
stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL);
if (!stack)
goto out;
err = -EINVAL;
lower = lowertmp;
for (numlower = 0; numlower < stacklen; numlower++) {
err = ovl_lower_dir(lower, &stack[numlower], ufs,
&sb->s_stack_depth, &remote);
if (err)
goto out_free_stack;
lower = strchr(lower, '\0') + 1;
}
err = -EINVAL;
sb->s_stack_depth++;
if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
pr_err("overlayfs: maximum fs stacking depth exceeded\n");
goto out_free_stack;
}
*stackp = stack;
*stacklenp = numlower;
if (remote)
sb->s_d_op = &ovl_reval_dentry_operations;
else
sb->s_d_op = &ovl_dentry_operations;
err = 0;
out:
kfree(lowertmp);
return err;
out_free_stack:
for (i = 0; i < numlower; i++)
path_put(&stack[i]);
kfree(stack);
goto out;
}
static int ovl_fill_super(struct super_block *sb, void *data, int silent)
{
struct path upperpath = { };
@ -903,12 +972,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
struct ovl_entry *oe;
struct ovl_fs *ufs;
struct path *stack = NULL;
char *lowertmp;
char *lower;
unsigned int numlower;
unsigned int stacklen = 0;
unsigned int numlower = 0;
unsigned int i;
bool remote = false;
struct cred *cred;
int err;
@ -948,45 +1013,10 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
sb->s_stack_depth = upperpath.mnt->mnt_sb->s_stack_depth;
}
err = -ENOMEM;
lowertmp = kstrdup(ufs->config.lowerdir, GFP_KERNEL);
if (!lowertmp)
err = ovl_get_lowerstack(sb, ufs, &stack, &numlower);
if (err)
goto out_unlock_workdentry;
err = -EINVAL;
stacklen = ovl_split_lowerdirs(lowertmp);
if (stacklen > OVL_MAX_STACK) {
pr_err("overlayfs: too many lower directories, limit is %d\n",
OVL_MAX_STACK);
goto out_free_lowertmp;
} else if (!ufs->config.upperdir && stacklen == 1) {
pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n");
goto out_free_lowertmp;
}
err = -ENOMEM;
stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL);
if (!stack)
goto out_free_lowertmp;
err = -EINVAL;
lower = lowertmp;
for (numlower = 0; numlower < stacklen; numlower++) {
err = ovl_lower_dir(lower, &stack[numlower], ufs,
&sb->s_stack_depth, &remote);
if (err)
goto out_put_lowerpath;
lower = strchr(lower, '\0') + 1;
}
err = -EINVAL;
sb->s_stack_depth++;
if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
pr_err("overlayfs: maximum fs stacking depth exceeded\n");
goto out_put_lowerpath;
}
if (ufs->config.upperdir) {
ufs->upper_mnt = clone_private_mount(&upperpath);
err = PTR_ERR(ufs->upper_mnt);
@ -1145,11 +1175,6 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
if (!ufs->indexdir)
ufs->config.index = false;
if (remote)
sb->s_d_op = &ovl_reval_dentry_operations;
else
sb->s_d_op = &ovl_dentry_operations;
err = -ENOMEM;
ufs->creator_cred = cred = prepare_creds();
if (!cred)
@ -1173,7 +1198,6 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
mntput(stack[i].mnt);
kfree(stack);
mntput(workpath.mnt);
kfree(lowertmp);
if (upperpath.dentry) {
oe->has_upper = true;
@ -1212,8 +1236,6 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
for (i = 0; i < numlower; i++)
path_put(&stack[i]);
kfree(stack);
out_free_lowertmp:
kfree(lowertmp);
out_unlock_workdentry:
if (ufs->workdir_locked)
ovl_inuse_unlock(workpath.dentry);