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ovl: generalize the lower_layers[] array 

Rename lower_layers[] array to layers[], extend its size by one and
initialize layers[0] with upper layer values.  Lower layers are now
addressed with index 1..numlower.  layers[0] is reserved even with lower
only overlay.

[SzM: replace ofs->numlower with ofs->numlayer, the latter's value is
incremented by one]

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
alistair/sensors
Amir Goldstein 2019-11-15 14:12:40 +02:00 committed by Miklos Szeredi
parent b504c6540d
commit 94375f9d51
4 changed files with 35 additions and 31 deletions
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6
fs/overlayfs/export.c
View File

@ -424,7 +424,6 @@ static struct dentry *ovl_lookup_real_inode(struct super_block *sb,
struct ovl_layer *layer) struct ovl_layer *layer)
{ {
struct ovl_fs *ofs = sb->s_fs_info; struct ovl_fs *ofs = sb->s_fs_info;
struct ovl_layer upper_layer = { .mnt = ofs->upper_mnt };
struct dentry *index = NULL; struct dentry *index = NULL;
struct dentry *this = NULL; struct dentry *this = NULL;
struct inode *inode; struct inode *inode;
@ -466,7 +465,7 @@ static struct dentry *ovl_lookup_real_inode(struct super_block *sb,
* recursive call walks back from indexed upper to the topmost * recursive call walks back from indexed upper to the topmost
* connected/hashed upper parent (or up to root). * connected/hashed upper parent (or up to root).
*/ */
this = ovl_lookup_real(sb, upper, &upper_layer); this = ovl_lookup_real(sb, upper, &ofs->layers[0]);
dput(upper); dput(upper);
} }
@ -646,8 +645,7 @@ static struct dentry *ovl_get_dentry(struct super_block *sb,
struct dentry *index) struct dentry *index)
{ {
struct ovl_fs *ofs = sb->s_fs_info; struct ovl_fs *ofs = sb->s_fs_info;
struct ovl_layer upper_layer = { .mnt = ofs->upper_mnt }; struct ovl_layer *layer = upper ? &ofs->layers[0] : lowerpath->layer;
struct ovl_layer *layer = upper ? &upper_layer : lowerpath->layer;
struct dentry *real = upper ?: (index ?: lowerpath->dentry); struct dentry *real = upper ?: (index ?: lowerpath->dentry);
/* /*

12
fs/overlayfs/namei.c
View File

@ -322,16 +322,16 @@ int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
struct dentry *origin = NULL; struct dentry *origin = NULL;
int i; int i;
for (i = 0; i < ofs->numlower; i++) { for (i = 1; i < ofs->numlayer; i++) {
/* /*
* If lower fs uuid is not unique among lower fs we cannot match * If lower fs uuid is not unique among lower fs we cannot match
* fh->uuid to layer. * fh->uuid to layer.
*/ */
if (ofs->lower_layers[i].fsid && if (ofs->layers[i].fsid &&
ofs->lower_layers[i].fs->bad_uuid) ofs->layers[i].fs->bad_uuid)
continue; continue;
origin = ovl_decode_real_fh(fh, ofs->lower_layers[i].mnt, origin = ovl_decode_real_fh(fh, ofs->layers[i].mnt,
connected); connected);
if (origin) if (origin)
break; break;
@ -354,7 +354,7 @@ int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
} }
**stackp = (struct ovl_path){ **stackp = (struct ovl_path){
.dentry = origin, .dentry = origin,
.layer = &ofs->lower_layers[i] .layer = &ofs->layers[i]
}; };
return 0; return 0;
@ -885,7 +885,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
if (!d.stop && poe->numlower) { if (!d.stop && poe->numlower) {
err = -ENOMEM; err = -ENOMEM;
stack = kcalloc(ofs->numlower, sizeof(struct ovl_path), stack = kcalloc(ofs->numlayer - 1, sizeof(struct ovl_path),
GFP_KERNEL); GFP_KERNEL);
if (!stack) if (!stack)
goto out_put_upper; goto out_put_upper;

4
fs/overlayfs/ovl_entry.h
View File

@ -45,10 +45,10 @@ struct ovl_path {
/* private information held for overlayfs's superblock */ /* private information held for overlayfs's superblock */
struct ovl_fs { struct ovl_fs {
struct vfsmount *upper_mnt; struct vfsmount *upper_mnt;
unsigned int numlower; unsigned int numlayer;
/* Number of unique lower sb that differ from upper sb */ /* Number of unique lower sb that differ from upper sb */
unsigned int numlowerfs; unsigned int numlowerfs;
struct ovl_layer *lower_layers; struct ovl_layer *layers;
struct ovl_sb *lower_fs; struct ovl_sb *lower_fs;
/* workbasedir is the path at workdir= mount option */ /* workbasedir is the path at workdir= mount option */
struct dentry *workbasedir; struct dentry *workbasedir;

44
fs/overlayfs/super.c
View File

@ -224,13 +224,13 @@ static void ovl_free_fs(struct ovl_fs *ofs)
if (ofs->upperdir_locked) if (ofs->upperdir_locked)
ovl_inuse_unlock(ofs->upper_mnt->mnt_root); ovl_inuse_unlock(ofs->upper_mnt->mnt_root);
mntput(ofs->upper_mnt); mntput(ofs->upper_mnt);
for (i = 0; i < ofs->numlower; i++) { for (i = 1; i < ofs->numlayer; i++) {
iput(ofs->lower_layers[i].trap); iput(ofs->layers[i].trap);
mntput(ofs->lower_layers[i].mnt); mntput(ofs->layers[i].mnt);
} }
for (i = 0; i < ofs->numlowerfs; i++) for (i = 0; i < ofs->numlowerfs; i++)
free_anon_bdev(ofs->lower_fs[i].pseudo_dev); free_anon_bdev(ofs->lower_fs[i].pseudo_dev);
kfree(ofs->lower_layers); kfree(ofs->layers);
kfree(ofs->lower_fs); kfree(ofs->lower_fs);
kfree(ofs->config.lowerdir); kfree(ofs->config.lowerdir);
@ -1319,16 +1319,16 @@ static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path)
return ofs->numlowerfs; return ofs->numlowerfs;
} }
static int ovl_get_lower_layers(struct super_block *sb, struct ovl_fs *ofs, static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs,
struct path *stack, unsigned int numlower) struct path *stack, unsigned int numlower)
{ {
int err; int err;
unsigned int i; unsigned int i;
err = -ENOMEM; err = -ENOMEM;
ofs->lower_layers = kcalloc(numlower, sizeof(struct ovl_layer), ofs->layers = kcalloc(numlower + 1, sizeof(struct ovl_layer),
GFP_KERNEL); GFP_KERNEL);
if (ofs->lower_layers == NULL) if (ofs->layers == NULL)
goto out; goto out;
ofs->lower_fs = kcalloc(numlower, sizeof(struct ovl_sb), ofs->lower_fs = kcalloc(numlower, sizeof(struct ovl_sb),
@ -1336,6 +1336,12 @@ static int ovl_get_lower_layers(struct super_block *sb, struct ovl_fs *ofs,
if (ofs->lower_fs == NULL) if (ofs->lower_fs == NULL)
goto out; goto out;
/* idx 0 is reserved for upper fs even with lower only overlay */
ofs->layers[0].mnt = ofs->upper_mnt;
ofs->layers[0].idx = 0;
ofs->layers[0].fsid = 0;
ofs->numlayer = 1;
for (i = 0; i < numlower; i++) { for (i = 0; i < numlower; i++) {
struct vfsmount *mnt; struct vfsmount *mnt;
struct inode *trap; struct inode *trap;
@ -1369,15 +1375,15 @@ static int ovl_get_lower_layers(struct super_block *sb, struct ovl_fs *ofs,
*/ */
mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME;
ofs->lower_layers[ofs->numlower].trap = trap; ofs->layers[ofs->numlayer].trap = trap;
ofs->lower_layers[ofs->numlower].mnt = mnt; ofs->layers[ofs->numlayer].mnt = mnt;
ofs->lower_layers[ofs->numlower].idx = i + 1; ofs->layers[ofs->numlayer].idx = ofs->numlayer;
ofs->lower_layers[ofs->numlower].fsid = fsid; ofs->layers[ofs->numlayer].fsid = fsid;
if (fsid) { if (fsid) {
ofs->lower_layers[ofs->numlower].fs = ofs->layers[ofs->numlayer].fs =
&ofs->lower_fs[fsid - 1]; &ofs->lower_fs[fsid - 1];
} }
ofs->numlower++; ofs->numlayer++;
} }
/* /*
@ -1464,7 +1470,7 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb,
goto out_err; goto out_err;
} }
err = ovl_get_lower_layers(sb, ofs, stack, numlower); err = ovl_get_layers(sb, ofs, stack, numlower);
if (err) if (err)
goto out_err; goto out_err;
@ -1475,7 +1481,7 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb,
for (i = 0; i < numlower; i++) { for (i = 0; i < numlower; i++) {
oe->lowerstack[i].dentry = dget(stack[i].dentry); oe->lowerstack[i].dentry = dget(stack[i].dentry);
oe->lowerstack[i].layer = &ofs->lower_layers[i]; oe->lowerstack[i].layer = &ofs->layers[i+1];
} }
if (remote) if (remote)
@ -1556,9 +1562,9 @@ static int ovl_check_overlapping_layers(struct super_block *sb,
return err; return err;
} }
for (i = 0; i < ofs->numlower; i++) { for (i = 1; i < ofs->numlayer; i++) {
err = ovl_check_layer(sb, ofs, err = ovl_check_layer(sb, ofs,
ofs->lower_layers[i].mnt->mnt_root, ofs->layers[i].mnt->mnt_root,
"lowerdir"); "lowerdir");
if (err) if (err)
return err; return err;