[PATCH v6 12/22] erofs: add cookie context helper functions

Jeffle Xu
2022-03-25T12:23:54Z

Introduce "struct erofs_fscache" for managing cookie for backinig file,
and helper functions for initializing and cleaning up this context
structure.

Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
---
fs/erofs/fscache.c | 61 +++++++++++++++++++++++++++++++++++++++++++++
fs/erofs/internal.h | 14 +++++++++++
2 files changed, 75 insertions(+)

diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
index 08cf570a0810..73235fd43bf6 100644
--- a/fs/erofs/fscache.c
+++ b/fs/erofs/fscache.c
@@ -7,6 +7,67 @@

static struct fscache_volume *volume;

+static int erofs_fscache_init_cookie(struct erofs_fscache *ctx, char *path)
+{
+ struct fscache_cookie *cookie;
+
+ cookie = fscache_acquire_cookie(volume, FSCACHE_ADV_WANT_CACHE_SIZE,
+ path, strlen(path),
+ NULL, 0, 0);
+ if (!cookie)
+ return -EINVAL;
+
+ fscache_use_cookie(cookie, false);
+ ctx->cookie = cookie;
+ return 0;
+}
+
+static inline void erofs_fscache_cleanup_cookie(struct erofs_fscache *ctx)
+{
+ struct fscache_cookie *cookie = ctx->cookie;
+
+ fscache_unuse_cookie(cookie, NULL, NULL);
+ fscache_relinquish_cookie(cookie, false);
+ ctx->cookie = NULL;
+}
+
+/*
+ * erofs_fscache_get - create an fscache context for blob file
+ * @sb: superblock
+ * @path: name of blob file
+ *
+ * Return: fscache context on success, ERR_PTR() on failure.
+ */
+struct erofs_fscache *erofs_fscache_get(struct super_block *sb, char *path)
+{
+ struct erofs_fscache *ctx;
+ int ret;
+
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return ERR_PTR(-ENOMEM);
+
+ ret = erofs_fscache_init_cookie(ctx, path);
+ if (ret) {
+ erofs_err(sb, "failed to init cookie");
+ goto err;
+ }
+
+ return ctx;
+err:
+ kfree(ctx);
+ return ERR_PTR(ret);
+}
+
+void erofs_fscache_put(struct erofs_fscache *ctx)
+{
+ if (!ctx)
+ return;
+
+ erofs_fscache_cleanup_cookie(ctx);
+ kfree(ctx);
+}
+
int __init erofs_init_fscache(void)
{
volume = fscache_acquire_volume("erofs", NULL, NULL, 0);
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 45b8b0dd8a27..d4f2b43cedae 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -96,6 +96,10 @@ struct erofs_sb_lz4_info {
u16 max_pclusterblks;
};

+struct erofs_fscache {
+ struct fscache_cookie *cookie;
+};
+
struct erofs_sb_info {
struct erofs_mount_opts opt; /* options */
#ifdef CONFIG_EROFS_FS_ZIP
@@ -620,9 +624,19 @@ static inline int z_erofs_load_lzma_config(struct super_block *sb,
#ifdef CONFIG_EROFS_FS_ONDEMAND
int erofs_init_fscache(void);
void erofs_exit_fscache(void);
+
+struct erofs_fscache *erofs_fscache_get(struct super_block *sb, char *path);
+void erofs_fscache_put(struct erofs_fscache *ctx);
#else
static inline int erofs_init_fscache(void) { return 0; }
static inline void erofs_exit_fscache(void) {}
+
+static inline struct erofs_fscache *erofs_fscache_get(struct super_block *sb,
+ char *path)
+{
+ return ERR_PTR(-EOPNOTSUPP);
+}
+static inline void erofs_fscache_put(struct erofs_fscache *ctx) {}
#endif

#define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */
--
2.27.0