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https://github.com/ibm-s390-linux/s390-tools.git
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zdsfs: add online vtoc refresh
Enable zdsfs to access datasets that were created after zdsfs was mounted without the need to remount zdsfs. This is done by re-reading the VTOC with every readdir system call. To ensure a consistent VTOC state the DASD device is reserved for every VTOC read and released afterwards. Signed-off-by: Stefan Haberland <sth@linux.ibm.com> Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com> Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
This commit is contained in:
Stefan Haberland
committed by
Jan Höppner
Jan Höppner
parent
e9c030f202
commit
bc053a975a
+79
-105
@@ -22,8 +22,6 @@
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#include "lib/dasd_base.h"
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#include "lib/libzds.h"
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#include "lib/u2s.h"
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#include "lib/util_base.h"
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#include "lib/util_list.h"
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#include "lib/vtoc.h"
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/** @cond PRIVATE */
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@@ -70,42 +68,6 @@ struct errormsg {
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char text[ERRORMSG];
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};
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/**
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* As the VTOC is the data area on the DASD that describes all data sets,
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* this library will often have to refer to the various records in the VTOC.
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* To make this more efficiant, we will read the whole VTOC once and identify
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* all elements (DSCBs). The raw data of the VTOC tracks and the index to the
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* DSCBs is stored.
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*/
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struct raw_vtoc {
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/** @brief The raw track data */
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char *rawdata;
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/** @brief This size of the raw track data in bytes */
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unsigned long long rawdatasize;
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/** @brief An array with pointers to the various DSCBs in the rawdata */
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char **vtocindex;
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/** @brief Number of entries in the index */
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unsigned int vtocindexcount;
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/** @brief Number of records per VTOC track
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*
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* @note While the DS4DEVDT field in the format 4 DSCB names the number
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* if DSCBs per VTOC track, we count the records, which is DS4DEVDT + 1
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* for record 0.
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*/
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unsigned int vtoc_rec_per_track;
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/** @brief The track number in which the vtoc begins on the DASD */
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unsigned int vtoctrackoffset;
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/** @brief Start record of VTOC.
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*
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* The rawdata contains full tracks. This is the number of the first
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* record that actually belongs to the VTOC */
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unsigned int vtocrecno;
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/** @brief The DASD this vtoc was read from */
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struct dasd *dasd;
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/** @brief Detailed error messages in case of a problem */
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struct errorlog *log;
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};
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struct dscbiterator {
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/** @brief The raw_vtoc this iterator refers to */
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struct raw_vtoc *rawvtoc;
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@@ -113,31 +75,6 @@ struct dscbiterator {
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unsigned int i;
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};
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struct dasd {
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/** @brief List head used to store a list of DASDs in struct zdsroot */
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struct util_list_node list;
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/** @brief Name of the block device, e.g. /dev/dasde */
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char *device;
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/** @brief File descriptor for the block device.
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*
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* The device is kept open for as along as the library uses it.
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* This lets the system know that the device is still in use.
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*/
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int inusefd;
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/* @brief where to find the volume label */
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unsigned int label_block;
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/** @brief Device geometry. How many cylinders does the DASD have. */
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unsigned int cylinders;
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/** @brief Device geometry. How many heads does the DASD have. */
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unsigned int heads;
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/** @brief The VTOC data that has been read from this device */
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struct raw_vtoc *rawvtoc;
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/** @brief The volume label that has been read from this device */
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volume_label_t *vlabel;
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/** @brief Detailed error messages in case of a problem */
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struct errorlog *log;
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};
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struct dasdhandle {
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/** @brief The struct dasd this context relates to */
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struct dasd *dasd;
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@@ -412,6 +349,29 @@ int lzds_zdsroot_alloc(struct zdsroot **root)
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return 0;
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}
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/**
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* It should be noted that this frees all structures that are owned by the
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* root structure as well. For example, a pointer to a struct dasd that
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* has been returned by lzds_zdsroot_add_device is not valid anymore.
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*
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* @param[in] root Reference to the zdsroot structure that is to be freed.
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*/
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void lzds_dslist_free(struct zdsroot *root)
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{
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struct dataset *ds, *nextds;
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int i;
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util_list_iterate_safe(root->datasetlist, ds, nextds) {
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util_list_remove(root->datasetlist, ds);
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dataset_free_memberlist(ds);
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for (i = 0; i < MAXVOLUMESPERDS; ++i)
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free(ds->dsp[i]);
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errorlog_free(ds->log);
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free(ds);
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}
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}
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/**
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* It should be noted that this frees all structures that are owned by the
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* root structure as well. For example, a pointer to a struct dasd that
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@@ -422,8 +382,6 @@ int lzds_zdsroot_alloc(struct zdsroot **root)
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void lzds_zdsroot_free(struct zdsroot *root)
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{
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struct dasd *dasd, *nextdasd;
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struct dataset *ds, *nextds;
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int i;
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if (!root)
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return;
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@@ -433,15 +391,7 @@ void lzds_zdsroot_free(struct zdsroot *root)
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dasd_free(dasd);
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}
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util_list_free(root->dasdlist);
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util_list_iterate_safe(root->datasetlist, ds, nextds) {
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util_list_remove(root->datasetlist, ds);
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dataset_free_memberlist(ds);
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for (i = 0; i < MAXVOLUMESPERDS; ++i)
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free(ds->dsp[i]);
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errorlog_free(ds->log);
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free(ds);
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}
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lzds_dslist_free(root);
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util_list_free(root->datasetlist);
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errorlog_free(root->log);
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free(root);
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@@ -1443,7 +1393,7 @@ int lzds_raw_vtoc_get_dscb_from_cchhb(struct raw_vtoc *rv, cchhb_t *p,
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* - EPROTO The VTOC data is not in a valid format.
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* - EIO Other I/O error
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*/
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int lzds_dasd_read_rawvtoc(struct dasd *dasd)
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int lzds_dasd_read_rawvtoc(struct dasd *dasd, struct raw_vtoc *rawvtoc)
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{
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unsigned long long vtoctrckno, vtocrecno;
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unsigned int vtoctrack_start, vtoctrack_end, vtocindexsize;
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@@ -1455,26 +1405,11 @@ int lzds_dasd_read_rawvtoc(struct dasd *dasd)
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format4_label_t *f4;
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unsigned long long rawvtocsize;
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struct raw_vtoc *rawvtoc = NULL;
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volume_label_t *vlabel = NULL;
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char *trackdata = NULL;
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char vol1[] = {0xe5, 0xd6, 0xd3, 0xf1, 0x00}; /* "VOL1" in EBCDIC */
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errorlog_clear(dasd->log);
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/* cleanup the old rawvtoc structures before we read new ones */
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rawvtoc = dasd->rawvtoc;
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dasd->rawvtoc = NULL;
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if (rawvtoc) {
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free(rawvtoc->rawdata);
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free(rawvtoc->vtocindex);
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free(rawvtoc);
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}
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rawvtoc = malloc(sizeof(*rawvtoc));
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if (!rawvtoc)
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return ENOMEM;
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memset(rawvtoc, 0, sizeof(*rawvtoc));
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rawvtoc->dasd = dasd;
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rc = lzds_dasd_get_vlabel(dasd, &vlabel);
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if (rc) {
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@@ -1611,13 +1546,49 @@ int lzds_dasd_read_rawvtoc(struct dasd *dasd)
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++i;
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}
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dasd->rawvtoc = rawvtoc;
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return 0;
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cleanup:
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free(rawvtoc->vtocindex);
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free(trackdata);
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free(rawvtoc);
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return rc;
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}
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/**
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* @param[in] dasd The struct dasd that represents the device we want to read
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* the VTOC from.
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* @return 0 on success, otherwise one of the following error codes:
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* - ENOMEM Could not allocate internal structure due to lack of memory.
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* - EINVAL The volume label has not yet been read or it is not valid.
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* - EPROTO The VTOC data is not in a valid format.
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* - EIO Other I/O error
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*/
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int lzds_dasd_alloc_rawvtoc(struct dasd *dasd)
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{
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struct raw_vtoc *rawvtoc = NULL;
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int rc;
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/* cleanup the old rawvtoc structures before we read new ones */
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rawvtoc = dasd->rawvtoc;
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dasd->rawvtoc = NULL;
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if (rawvtoc) {
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free(rawvtoc->rawdata);
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free(rawvtoc->vtocindex);
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free(rawvtoc);
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}
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rawvtoc = malloc(sizeof(*rawvtoc));
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if (!rawvtoc)
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return ENOMEM;
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memset(rawvtoc, 0, sizeof(*rawvtoc));
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rawvtoc->dasd = dasd;
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rc = lzds_dasd_read_rawvtoc(dasd, rawvtoc);
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if (rc) {
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free(rawvtoc->vtocindex);
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free(rawvtoc);
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} else {
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dasd->rawvtoc = rawvtoc;
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}
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return rc;
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}
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@@ -2261,6 +2232,7 @@ out1:
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static int dataset_merge_dataset(struct dataset *baseds, struct dataset *newds)
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{
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int k, l, dspcount;
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for (k = 0; k < MAXVOLUMESPERDS; ++k) {
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/* if both datasets have a part in position k,
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* then something is wrong */
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@@ -2280,18 +2252,20 @@ static int dataset_merge_dataset(struct dataset *baseds, struct dataset *newds)
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* Since dsp[0] may not be set yet, we loop over the
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* base dsp array until we find an entry.
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*/
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for (l = 0; l < MAXVOLUMESPERDS; ++l)
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if (baseds->dsp[l]) {
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if (memcmp(baseds->dsp[l]->f1->DS1DSSN,
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newds->dsp[k]->f1->DS1DSSN,
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MAXVOLSER))
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return errorlog_add_message(
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&baseds->log, NULL, EPROTO,
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"merge dataset: part %d has incompatible"
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" base volume serial\n", k);
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else
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break;
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}
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for (l = 0; l < MAXVOLUMESPERDS; ++l) {
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if (!baseds->dsp[l])
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continue;
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if (memcmp(baseds->dsp[l]->f1->DS1DSSN,
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newds->dsp[k]->f1->DS1DSSN,
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MAXVOLSER))
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return errorlog_add_message(
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&baseds->log, NULL, EPROTO,
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"merge dataset: part %d has incompatible base volume serial\n",
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k);
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else
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break;
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}
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baseds->dsp[k] = newds->dsp[k];
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baseds->dspcount++;
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