diff options
Diffstat (limited to 'fs/overlayfs/copy_up.c')
-rw-r--r-- | fs/overlayfs/copy_up.c | 188 |
1 files changed, 160 insertions, 28 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index eb3b8d39fb61..d855f508fa20 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -232,13 +232,13 @@ int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat) return err; } -struct ovl_fh *ovl_encode_fh(struct dentry *lower, bool is_upper) +struct ovl_fh *ovl_encode_fh(struct dentry *real, bool is_upper) { struct ovl_fh *fh; int fh_type, fh_len, dwords; void *buf; int buflen = MAX_HANDLE_SZ; - uuid_t *uuid = &lower->d_sb->s_uuid; + uuid_t *uuid = &real->d_sb->s_uuid; buf = kmalloc(buflen, GFP_KERNEL); if (!buf) @@ -250,7 +250,7 @@ struct ovl_fh *ovl_encode_fh(struct dentry *lower, bool is_upper) * the price or reconnecting the dentry. */ dwords = buflen >> 2; - fh_type = exportfs_encode_fh(lower, buf, &dwords, 0); + fh_type = exportfs_encode_fh(real, buf, &dwords, 0); buflen = (dwords << 2); fh = ERR_PTR(-EIO); @@ -288,8 +288,8 @@ out: return fh; } -static int ovl_set_origin(struct dentry *dentry, struct dentry *lower, - struct dentry *upper) +int ovl_set_origin(struct dentry *dentry, struct dentry *lower, + struct dentry *upper) { const struct ovl_fh *fh = NULL; int err; @@ -315,6 +315,94 @@ static int ovl_set_origin(struct dentry *dentry, struct dentry *lower, return err; } +/* Store file handle of @upper dir in @index dir entry */ +static int ovl_set_upper_fh(struct dentry *upper, struct dentry *index) +{ + const struct ovl_fh *fh; + int err; + + fh = ovl_encode_fh(upper, true); + if (IS_ERR(fh)) + return PTR_ERR(fh); + + err = ovl_do_setxattr(index, OVL_XATTR_UPPER, fh, fh->len, 0); + + kfree(fh); + return err; +} + +/* + * Create and install index entry. + * + * Caller must hold i_mutex on indexdir. + */ +static int ovl_create_index(struct dentry *dentry, struct dentry *origin, + struct dentry *upper) +{ + struct dentry *indexdir = ovl_indexdir(dentry->d_sb); + struct inode *dir = d_inode(indexdir); + struct dentry *index = NULL; + struct dentry *temp = NULL; + struct qstr name = { }; + int err; + + /* + * For now this is only used for creating index entry for directories, + * because non-dir are copied up directly to index and then hardlinked + * to upper dir. + * + * TODO: implement create index for non-dir, so we can call it when + * encoding file handle for non-dir in case index does not exist. + */ + if (WARN_ON(!d_is_dir(dentry))) + return -EIO; + + /* Directory not expected to be indexed before copy up */ + if (WARN_ON(ovl_test_flag(OVL_INDEX, d_inode(dentry)))) + return -EIO; + + err = ovl_get_index_name(origin, &name); + if (err) + return err; + + temp = ovl_lookup_temp(indexdir); + if (IS_ERR(temp)) + goto temp_err; + + err = ovl_do_mkdir(dir, temp, S_IFDIR, true); + if (err) + goto out; + + err = ovl_set_upper_fh(upper, temp); + if (err) + goto out_cleanup; + + index = lookup_one_len(name.name, indexdir, name.len); + if (IS_ERR(index)) { + err = PTR_ERR(index); + } else { + err = ovl_do_rename(dir, temp, dir, index, 0); + dput(index); + } + + if (err) + goto out_cleanup; + +out: + dput(temp); + kfree(name.name); + return err; + +temp_err: + err = PTR_ERR(temp); + temp = NULL; + goto out; + +out_cleanup: + ovl_cleanup(dir, temp); + goto out; +} + struct ovl_copy_up_ctx { struct dentry *parent; struct dentry *dentry; @@ -327,6 +415,7 @@ struct ovl_copy_up_ctx { struct dentry *workdir; bool tmpfile; bool origin; + bool indexed; }; static int ovl_link_up(struct ovl_copy_up_ctx *c) @@ -361,7 +450,10 @@ static int ovl_link_up(struct ovl_copy_up_ctx *c) } } inode_unlock(udir); - ovl_set_nlink_upper(c->dentry); + if (err) + return err; + + err = ovl_set_nlink_upper(c->dentry); return err; } @@ -498,6 +590,12 @@ static int ovl_copy_up_locked(struct ovl_copy_up_ctx *c) if (err) goto out_cleanup; + if (S_ISDIR(c->stat.mode) && c->indexed) { + err = ovl_create_index(c->dentry, c->lowerpath.dentry, temp); + if (err) + goto out_cleanup; + } + if (c->tmpfile) { inode_lock_nested(udir, I_MUTEX_PARENT); err = ovl_install_temp(c, temp, &newdentry); @@ -536,20 +634,33 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) { int err; struct ovl_fs *ofs = c->dentry->d_sb->s_fs_info; - bool indexed = false; + bool to_index = false; - if (ovl_indexdir(c->dentry->d_sb) && !S_ISDIR(c->stat.mode) && - c->stat.nlink > 1) - indexed = true; + /* + * Indexed non-dir is copied up directly to the index entry and then + * hardlinked to upper dir. Indexed dir is copied up to indexdir, + * then index entry is created and then copied up dir installed. + * Copying dir up to indexdir instead of workdir simplifies locking. + */ + if (ovl_need_index(c->dentry)) { + c->indexed = true; + if (S_ISDIR(c->stat.mode)) + c->workdir = ovl_indexdir(c->dentry->d_sb); + else + to_index = true; + } - if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || indexed) + if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || to_index) c->origin = true; - if (indexed) { + if (to_index) { c->destdir = ovl_indexdir(c->dentry->d_sb); err = ovl_get_index_name(c->lowerpath.dentry, &c->destname); if (err) return err; + } else if (WARN_ON(!c->parent)) { + /* Disconnected dentry must be copied up to index dir */ + return -EIO; } else { /* * Mark parent "impure" because it may now contain non-pure @@ -572,11 +683,17 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) } } - if (indexed) { - if (!err) - ovl_set_flag(OVL_INDEX, d_inode(c->dentry)); - kfree(c->destname.name); - } else if (!err) { + + if (err) + goto out; + + if (c->indexed) + ovl_set_flag(OVL_INDEX, d_inode(c->dentry)); + + if (to_index) { + /* Initialize nlink for copy up of disconnected dentry */ + err = ovl_set_nlink_upper(c->dentry); + } else { struct inode *udir = d_inode(c->destdir); /* Restore timestamps on parent (best effort) */ @@ -587,6 +704,9 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) ovl_dentry_set_upper_alias(c->dentry); } +out: + if (to_index) + kfree(c->destname.name); return err; } @@ -611,14 +731,17 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, if (err) return err; - ovl_path_upper(parent, &parentpath); - ctx.destdir = parentpath.dentry; - ctx.destname = dentry->d_name; + if (parent) { + ovl_path_upper(parent, &parentpath); + ctx.destdir = parentpath.dentry; + ctx.destname = dentry->d_name; - err = vfs_getattr(&parentpath, &ctx.pstat, - STATX_ATIME | STATX_MTIME, AT_STATX_SYNC_AS_STAT); - if (err) - return err; + err = vfs_getattr(&parentpath, &ctx.pstat, + STATX_ATIME | STATX_MTIME, + AT_STATX_SYNC_AS_STAT); + if (err) + return err; + } /* maybe truncate regular file. this has no effect on dirs */ if (flags & O_TRUNC) @@ -639,7 +762,7 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, } else { if (!ovl_dentry_upper(dentry)) err = ovl_do_copy_up(&ctx); - if (!err && !ovl_dentry_has_upper_alias(dentry)) + if (!err && parent && !ovl_dentry_has_upper_alias(dentry)) err = ovl_link_up(&ctx); ovl_copy_up_end(dentry); } @@ -652,10 +775,19 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags) { int err = 0; const struct cred *old_cred = ovl_override_creds(dentry->d_sb); + bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED); + + /* + * With NFS export, copy up can get called for a disconnected non-dir. + * In this case, we will copy up lower inode to index dir without + * linking it to upper dir. + */ + if (WARN_ON(disconnected && d_is_dir(dentry))) + return -EIO; while (!err) { struct dentry *next; - struct dentry *parent; + struct dentry *parent = NULL; /* * Check if copy-up has happened as well as for upper alias (in @@ -671,12 +803,12 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags) * with rename. */ if (ovl_dentry_upper(dentry) && - ovl_dentry_has_upper_alias(dentry)) + (ovl_dentry_has_upper_alias(dentry) || disconnected)) break; next = dget(dentry); /* find the topmost dentry not yet copied up */ - for (;;) { + for (; !disconnected;) { parent = dget_parent(next); if (ovl_dentry_upper(parent)) |