leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

ovl: consistent d_ino for non-samefs with xino

Browse Source 
When overlay layers are not all on the same fs, but all inode numbers
of underlying fs do not use the high 'xino' bits, overlay st_ino values
are constant and persistent.

In that case, relax non-samefs constraint for consistent d_ino and always
iterate non-merge dir using ovl_fill_real() actor so we can remap lower
inode numbers to unique lower fs range.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Amir Goldstein 2017-11-06 16:48:02 +02:00 committed by Miklos Szeredi
parent 12574a9f4c
commit adbf4f7ea8
1 changed files with 39 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
fs/overlayfs/readdir.c
View File

@ -120,6 +120,10 @@ static bool ovl_calc_d_ino(struct ovl_readdir_data *rdd,
if (!rdd->dentry)
return false;
/* Always recalc d_ino when remapping lower inode numbers */
if (ovl_xino_bits(rdd->dentry->d_sb))
return true;
/* Always recalc d_ino for parent */
if (strcmp(p->name, "..") == 0)
return true;
@ -435,6 +439,19 @@ static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry)
return cache;
}
/* Map inode number to lower fs unique range */
static u64 ovl_remap_lower_ino(u64 ino, int xinobits, int fsid,
const char *name, int namelen)
{
if (ino >> (64 - xinobits)) {
pr_warn_ratelimited("overlayfs: d_ino too big (%.*s, ino=%llu, xinobits=%d)\n",
namelen, name, ino, xinobits);
return ino;
}
return ino | ((u64)fsid) << (64 - xinobits);
}
/*
* Set d_ino for upper entries. Non-upper entries should always report
* the uppermost real inode ino and should not call this function.
@ -452,9 +469,10 @@ static int ovl_cache_update_ino(struct path *path, struct ovl_cache_entry *p)
struct dentry *this = NULL;
enum ovl_path_type type;
u64 ino = p->real_ino;
int xinobits = ovl_xino_bits(dir->d_sb);
int err = 0;
if (!ovl_same_sb(dir->d_sb))
if (!ovl_same_sb(dir->d_sb) && !xinobits)
goto out;
if (p->name[0] == '.') {
@ -491,6 +509,10 @@ get:
WARN_ON_ONCE(dir->d_sb->s_dev != stat.dev);
ino = stat.ino;
} else if (xinobits && !OVL_TYPE_UPPER(type)) {
ino = ovl_remap_lower_ino(ino, xinobits,
ovl_layer_lower(this)->fsid,
p->name, p->len);
}
out:
@ -618,6 +640,8 @@ struct ovl_readdir_translate {
struct ovl_dir_cache *cache;
struct dir_context ctx;
u64 parent_ino;
int fsid;
int xinobits;
};
static int ovl_fill_real(struct dir_context *ctx, const char *name,
@ -628,14 +652,17 @@ static int ovl_fill_real(struct dir_context *ctx, const char *name,
container_of(ctx, struct ovl_readdir_translate, ctx);
struct dir_context *orig_ctx = rdt->orig_ctx;
if (rdt->parent_ino && strcmp(name, "..") == 0)
if (rdt->parent_ino && strcmp(name, "..") == 0) {
ino = rdt->parent_ino;
else if (rdt->cache) {
} else if (rdt->cache) {
struct ovl_cache_entry *p;
p = ovl_cache_entry_find(&rdt->cache->root, name, namelen);
if (p)
ino = p->ino;
} else if (rdt->xinobits) {
ino = ovl_remap_lower_ino(ino, rdt->xinobits, rdt->fsid,
name, namelen);
}
return orig_ctx->actor(orig_ctx, name, namelen, offset, ino, d_type);
@ -646,11 +673,16 @@ static int ovl_iterate_real(struct file *file, struct dir_context *ctx)
int err;
struct ovl_dir_file *od = file->private_data;
struct dentry *dir = file->f_path.dentry;
struct ovl_layer *lower_layer = ovl_layer_lower(dir);
struct ovl_readdir_translate rdt = {
.ctx.actor = ovl_fill_real,
.orig_ctx = ctx,
.xinobits = ovl_xino_bits(dir->d_sb),
};
if (rdt.xinobits && lower_layer)
rdt.fsid = lower_layer->fsid;
if (OVL_TYPE_MERGE(ovl_path_type(dir->d_parent))) {
struct kstat stat;
struct path statpath = file->f_path;
@ -693,9 +725,10 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx)
* dir is impure then need to adjust d_ino for copied up
* entries.
*/
if (ovl_same_sb(dentry->d_sb) &&
(ovl_test_flag(OVL_IMPURE, d_inode(dentry)) ||
OVL_TYPE_MERGE(ovl_path_type(dentry->d_parent)))) {
if (ovl_xino_bits(dentry->d_sb) ||
(ovl_same_sb(dentry->d_sb) &&
(ovl_test_flag(OVL_IMPURE, d_inode(dentry)) ||
OVL_TYPE_MERGE(ovl_path_type(dentry->d_parent))))) {
return ovl_iterate_real(file, ctx);
}
return iterate_dir(od->realfile, ctx);