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ovl: decode lower file handles of unlinked but open files 

Lookup overlay inode in cache by origin inode, so we can decode a file
handle of an open file even if the index has a whiteout index entry to
mark this overlay inode was unlinked.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Amir Goldstein 2017-12-24 18:28:04 +02:00 committed by Miklos Szeredi
parent f71bd9cfb6
commit 9436a1a339
3 changed files with 38 additions and 2 deletions
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23
fs/overlayfs/export.c
View File

@ -443,14 +443,22 @@ static struct dentry *ovl_lower_fh_to_d(struct super_block *sb,
struct ovl_path *stack = &origin;
struct dentry *dentry = NULL;
struct dentry *index = NULL;
struct inode *inode = NULL;
bool is_deleted = false;
int err;
/* First lookup indexed upper by fh */
if (ofs->indexdir) {
index = ovl_get_index_fh(ofs, fh);
err = PTR_ERR(index);
if (IS_ERR(index))
return ERR_PTR(err);
if (IS_ERR(index)) {
if (err != -ESTALE)
return ERR_PTR(err);
/* Found a whiteout index - treat as deleted inode */
is_deleted = true;
index = NULL;
}
}
/* Then lookup origin by fh */
@ -461,6 +469,16 @@ static struct dentry *ovl_lower_fh_to_d(struct super_block *sb,
err = ovl_verify_origin(index, origin.dentry, false);
if (err)
goto out_err;
} else if (is_deleted) {
/* Lookup deleted non-dir by origin inode */
if (!d_is_dir(origin.dentry))
inode = ovl_lookup_inode(sb, origin.dentry);
err = -ESTALE;
if (!inode || atomic_read(&inode->i_count) == 1)
goto out_err;
/* Deleted but still open? */
index = dget(ovl_i_dentry_upper(inode));
}
dentry = ovl_get_dentry(sb, NULL, &origin, index);
@ -468,6 +486,7 @@ static struct dentry *ovl_lower_fh_to_d(struct super_block *sb,
out:
dput(origin.dentry);
dput(index);
iput(inode);
return dentry;
out_err:

16
fs/overlayfs/inode.c
View File

@ -645,6 +645,22 @@ static bool ovl_verify_inode(struct inode *inode, struct dentry *lowerdentry,
return true;
}
struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *origin)
{
struct inode *inode, *key = d_inode(origin);
inode = ilookup5(sb, (unsigned long) key, ovl_inode_test, key);
if (!inode)
return NULL;
if (!ovl_verify_inode(inode, origin, NULL)) {
iput(inode);
return ERR_PTR(-ESTALE);
}
return inode;
}
struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry,
struct dentry *lowerdentry, struct dentry *index,
unsigned int numlower)

1
fs/overlayfs/overlayfs.h
View File

@ -322,6 +322,7 @@ int ovl_update_time(struct inode *inode, struct timespec *ts, int flags);
bool ovl_is_private_xattr(const char *name);
struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *origin);
struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry,
struct dentry *lowerdentry, struct dentry *index,
unsigned int numlower);