From d03382ce9a89dbe27cba25130f0b90c0d631d5c5 Mon Sep 17 00:00:00 2001 From: Suresh Jayaraman Date: Mon, 5 Jul 2010 18:12:27 +0530 Subject: cifs: define superblock-level cache index objects and register them Define superblock-level cache index objects (managed by cifsTconInfo structs). Each superblock object is created in a server-level index object and in itself an index into which inode-level objects are inserted. The superblock object is keyed by sharename. The UniqueId/IndexNumber is used to validate that the exported share is the same since we accessed it last time. Signed-off-by: Suresh Jayaraman Signed-off-by: Steve French --- fs/cifs/cache.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 109 insertions(+) (limited to 'fs/cifs/cache.c') diff --git a/fs/cifs/cache.c b/fs/cifs/cache.c index f46468fb6a9..15532abdac1 100644 --- a/fs/cifs/cache.c +++ b/fs/cifs/cache.c @@ -106,3 +106,112 @@ const struct fscache_cookie_def cifs_fscache_server_index_def = { .type = FSCACHE_COOKIE_TYPE_INDEX, .get_key = cifs_server_get_key, }; + +/* + * Auxiliary data attached to CIFS superblock within the cache + */ +struct cifs_fscache_super_auxdata { + u64 resource_id; /* unique server resource id */ +}; + +static char *extract_sharename(const char *treename) +{ + const char *src; + char *delim, *dst; + int len; + + /* skip double chars at the beginning */ + src = treename + 2; + + /* share name is always preceded by '\\' now */ + delim = strchr(src, '\\'); + if (!delim) + return ERR_PTR(-EINVAL); + delim++; + len = strlen(delim); + + /* caller has to free the memory */ + dst = kstrndup(delim, len, GFP_KERNEL); + if (!dst) + return ERR_PTR(-ENOMEM); + + return dst; +} + +/* + * Superblock object currently keyed by share name + */ +static uint16_t cifs_super_get_key(const void *cookie_netfs_data, void *buffer, + uint16_t maxbuf) +{ + const struct cifsTconInfo *tcon = cookie_netfs_data; + char *sharename; + uint16_t len; + + sharename = extract_sharename(tcon->treeName); + if (IS_ERR(sharename)) { + cFYI(1, "CIFS: couldn't extract sharename\n"); + sharename = NULL; + return 0; + } + + len = strlen(sharename); + if (len > maxbuf) + return 0; + + memcpy(buffer, sharename, len); + + kfree(sharename); + + return len; +} + +static uint16_t +cifs_fscache_super_get_aux(const void *cookie_netfs_data, void *buffer, + uint16_t maxbuf) +{ + struct cifs_fscache_super_auxdata auxdata; + const struct cifsTconInfo *tcon = cookie_netfs_data; + + memset(&auxdata, 0, sizeof(auxdata)); + auxdata.resource_id = tcon->resource_id; + + if (maxbuf > sizeof(auxdata)) + maxbuf = sizeof(auxdata); + + memcpy(buffer, &auxdata, maxbuf); + + return maxbuf; +} + +static enum +fscache_checkaux cifs_fscache_super_check_aux(void *cookie_netfs_data, + const void *data, + uint16_t datalen) +{ + struct cifs_fscache_super_auxdata auxdata; + const struct cifsTconInfo *tcon = cookie_netfs_data; + + if (datalen != sizeof(auxdata)) + return FSCACHE_CHECKAUX_OBSOLETE; + + memset(&auxdata, 0, sizeof(auxdata)); + auxdata.resource_id = tcon->resource_id; + + if (memcmp(data, &auxdata, datalen) != 0) + return FSCACHE_CHECKAUX_OBSOLETE; + + return FSCACHE_CHECKAUX_OKAY; +} + +/* + * Superblock object for FS-Cache + */ +const struct fscache_cookie_def cifs_fscache_super_index_def = { + .name = "CIFS.super", + .type = FSCACHE_COOKIE_TYPE_INDEX, + .get_key = cifs_super_get_key, + .get_aux = cifs_fscache_super_get_aux, + .check_aux = cifs_fscache_super_check_aux, +}; + -- cgit v1.2.3