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author | Al Viro <viro@zeniv.linux.org.uk> | 2018-12-23 22:02:47 +0100 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2019-02-28 09:29:27 +0100 |
commit | 0b52075ee62301dd150c9f2c3ddd0035ed894cde (patch) | |
tree | bb5b54d2fee0e0e37f73635030dc0e25e93c9aa5 /fs/fs_context.c | |
parent | convenience helpers: vfs_get_super() and sget_fc() (diff) | |
download | linux-0b52075ee62301dd150c9f2c3ddd0035ed894cde.tar.xz linux-0b52075ee62301dd150c9f2c3ddd0035ed894cde.zip |
introduce cloning of fs_context
new primitive: vfs_dup_fs_context(). Comes with fs_context
method (->dup()) for copying the filesystem-specific parts
of fs_context, along with LSM one (->fs_context_dup()) for
doing the same to LSM parts.
[needs better commit message, and change of Author:, anyway]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/fs_context.c')
-rw-r--r-- | fs/fs_context.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/fs/fs_context.c b/fs/fs_context.c index aa7e0ffb591a..57f61833ac83 100644 --- a/fs/fs_context.c +++ b/fs/fs_context.c @@ -338,6 +338,47 @@ void fc_drop_locked(struct fs_context *fc) static void legacy_fs_context_free(struct fs_context *fc); /** + * vfs_dup_fc_config: Duplicate a filesystem context. + * @src_fc: The context to copy. + */ +struct fs_context *vfs_dup_fs_context(struct fs_context *src_fc) +{ + struct fs_context *fc; + int ret; + + if (!src_fc->ops->dup) + return ERR_PTR(-EOPNOTSUPP); + + fc = kmemdup(src_fc, sizeof(struct fs_context), GFP_KERNEL); + if (!fc) + return ERR_PTR(-ENOMEM); + + fc->fs_private = NULL; + fc->s_fs_info = NULL; + fc->source = NULL; + fc->security = NULL; + get_filesystem(fc->fs_type); + get_net(fc->net_ns); + get_user_ns(fc->user_ns); + get_cred(fc->cred); + + /* Can't call put until we've called ->dup */ + ret = fc->ops->dup(fc, src_fc); + if (ret < 0) + goto err_fc; + + ret = security_fs_context_dup(fc, src_fc); + if (ret < 0) + goto err_fc; + return fc; + +err_fc: + put_fs_context(fc); + return ERR_PTR(ret); +} +EXPORT_SYMBOL(vfs_dup_fs_context); + +/** * put_fs_context - Dispose of a superblock configuration context. * @fc: The context to dispose of. */ @@ -381,6 +422,31 @@ static void legacy_fs_context_free(struct fs_context *fc) } /* + * Duplicate a legacy config. + */ +static int legacy_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc) +{ + struct legacy_fs_context *ctx; + struct legacy_fs_context *src_ctx = src_fc->fs_private; + + ctx = kmemdup(src_ctx, sizeof(*src_ctx), GFP_KERNEL); + if (!ctx) + return -ENOMEM; + + if (ctx->param_type == LEGACY_FS_INDIVIDUAL_PARAMS) { + ctx->legacy_data = kmemdup(src_ctx->legacy_data, + src_ctx->data_size, GFP_KERNEL); + if (!ctx->legacy_data) { + kfree(ctx); + return -ENOMEM; + } + } + + fc->fs_private = ctx; + return 0; +} + +/* * Add a parameter to a legacy config. We build up a comma-separated list of * options. */ @@ -514,6 +580,7 @@ static int legacy_reconfigure(struct fs_context *fc) const struct fs_context_operations legacy_fs_context_ops = { .free = legacy_fs_context_free, + .dup = legacy_fs_context_dup, .parse_param = legacy_parse_param, .parse_monolithic = legacy_parse_monolithic, .get_tree = legacy_get_tree, |