From 67894d6086f073ef0663c4e12ad8c812ef3a9686 Mon Sep 17 00:00:00 2001 From: Andreas Dilger Date: Tue, 29 Apr 2014 02:57:21 -0600 Subject: [PATCH] LU-4974 lod: add comments for lod_pool.c functions Fix up GPL header block to reference proper GPLv2 license URL. Remove mention of contacting Sun, since they don't exist anymore. Add introductory comment block for the lod_pool.c file. Add function comment blocks to all functions in the lod_pool.c file. Minor cleanup of variable and function names for consistency, since they affect the code comments. Other code changes for issues found during commenting will be in separate follow-on patches. This patch specifically excludes changing cfs_list_t->struct list_head and similar cleanups, since they would touch too many lines of code in the patch to review easily. Signed-off-by: Andreas Dilger Change-Id: Id914f54bd67138d36041b5867541703a5a500c1e Reviewed-on: http://review.whamcloud.com/10145 Tested-by: Jenkins Reviewed-by: Ned Bass Reviewed-by: Dmitry Eremin Tested-by: Maloo Reviewed-by: Alexey Lyashkov Reviewed-by: Oleg Drokin --- lustre/lod/lod_pool.c | 461 ++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 370 insertions(+), 91 deletions(-) diff --git a/lustre/lod/lod_pool.c b/lustre/lod/lod_pool.c index f1a8059..6eaa6d7 100644 --- a/lustre/lod/lod_pool.c +++ b/lustre/lod/lod_pool.c @@ -14,12 +14,8 @@ * in the LICENSE file that accompanied this code). * * You should have received a copy of the GNU General Public License - * version 2 along with this program; If not, see [sun.com URL with a - * copy of GPLv2]. - * - * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, - * CA 95054 USA or visit www.sun.com if you need additional information or - * have any questions. + * version 2 along with this program; If not, see + * http://www.gnu.org/licenses/gpl-2.0.html * * GPL HEADER END */ @@ -27,16 +23,33 @@ * Copyright 2008 Sun Microsystems, Inc. All rights reserved * Use is subject to license terms. * - * Copyright (c) 2012, 2013, Intel Corporation. + * Copyright (c) 2012, 2014 Intel Corporation. */ /* * This file is part of Lustre, http://www.lustre.org/ * Lustre is a trademark of Sun Microsystems, Inc. - * + */ +/* * lustre/lod/lod_pool.c * * OST pool methods * + * This file provides code related to the Logical Object Device (LOD) + * handling of OST Pools on the MDT. Pools are named lists of targets + * that allow userspace to group targets that share a particlar property + * together so that users or kernel helpers can make decisions about file + * allocation based on these properties. For example, pools could be + * defined based on fault domains (e.g. separate racks of server nodes) so + * that RAID-1 mirroring could select targets from independent fault + * domains, or pools could define target performance characteristics so + * that applicatins could select IOP-optimized storage or stream-optimized + * storage for a particular output file. + * + * This file handles creation, lookup, and removal of pools themselves, as + * well as adding and removing targets to pools. It also handles lprocfs + * display of configured pool. The pools are accessed by name in the pool + * hash, and are refcounted to ensure proper pool structure lifetimes. + * * Author: Jacques-Charles LAFOUCRIERE * Author: Alex Lyashkov * Author: Nathaniel Rutman @@ -48,15 +61,37 @@ #include #include "lod_internal.h" -#define pool_tgt(_p, _i) \ - OST_TGT(lu2lod_dev((_p)->pool_lobd->obd_lu_dev),(_p)->pool_obds.op_array[_i]) +#define pool_tgt(_p, _i) OST_TGT(lu2lod_dev((_p)->pool_lobd->obd_lu_dev), \ + (_p)->pool_obds.op_array[_i]) -static void lod_pool_getref(struct pool_desc *pool) +/** + * Get a reference on the specified pool. + * + * To ensure the pool descriptor is not freed before the caller is finished + * with it. Any process that is accessing \a pool directly needs to hold + * reference on it, including /proc since a userspace thread may be holding + * the /proc file open and busy in the kernel. + * + * \param[in] pool pool descriptor on which to gain reference + */ +static void pool_getref(struct pool_desc *pool) { CDEBUG(D_INFO, "pool %p\n", pool); atomic_inc(&pool->pool_refcount); } +/** + * Drop a reference on the specified pool and free its memory if needed. + * + * One reference is held by the LOD OBD device while it is configured, from + * the time the configuration log defines the pool until the time when it is + * dropped when the LOD OBD is cleaned up or the pool is deleted. This means + * that the pool will not be freed while the LOD device is configured, unless + * it is explicitly destroyed by the sysadmin. The pool structure is freed + * after the last reference on the structure is released. + * + * \param[in] pool pool descriptor to drop reference on and possibly free + */ void lod_pool_putref(struct pool_desc *pool) { CDEBUG(D_INFO, "pool %p\n", pool); @@ -71,7 +106,17 @@ void lod_pool_putref(struct pool_desc *pool) } } -void lod_pool_putref_locked(struct pool_desc *pool) +/** + * Drop the refcount in cases where the caller holds a spinlock. + * + * This is needed if the caller cannot be blocked while freeing memory. + * It assumes that there is some other known refcount held on the \a pool + * and the memory cannot actually be freed, but the refcounting needs to + * be kept accurate. + * + * \param[in] pool pool descriptor on which to drop reference + */ +static void pool_putref_locked(struct pool_desc *pool) { CDEBUG(D_INFO, "pool %p\n", pool); LASSERT(atomic_read(&pool->pool_refcount) > 1); @@ -79,13 +124,25 @@ void lod_pool_putref_locked(struct pool_desc *pool) atomic_dec(&pool->pool_refcount); } - /* + * Group of functions needed for cfs_hash implementation. This + * includes pool lookup, refcounting, and cleanup. + */ + +/** + * Hash the pool name for use by the cfs_hash handlers. + * * hash function using a Rotating Hash algorithm * Knuth, D. The Art of Computer Programming, * Volume 3: Sorting and Searching, * Chapter 6.4. * Addison Wesley, 1973 + * + * \param[in] hash_body hash structure where this key is embedded (unused) + * \param[in] key key to be hashed (in this case the pool name) + * \param[in] mask bitmask to limit the hash value to the desired size + * + * \retval computed hash value from \a key and limited by \a mask */ static __u32 pool_hashfn(cfs_hash_t *hash_body, const void *key, unsigned mask) { @@ -98,19 +155,40 @@ static __u32 pool_hashfn(cfs_hash_t *hash_body, const void *key, unsigned mask) for (i = 0; i < LOV_MAXPOOLNAME; i++) { if (poolname[i] == '\0') break; - result = (result << 4)^(result >> 28) ^ poolname[i]; + result = (result << 4) ^ (result >> 28) ^ poolname[i]; } - return (result % mask); + return result % mask; } +/** + * Return the actual key (pool name) from the hashed \a hnode. + * + * Allows extracting the key name when iterating over all hash entries. + * + * \param[in] hnode hash node found by lookup or iteration + * + * \retval char array referencing the pool name (no refcount) + */ static void *pool_key(cfs_hlist_node_t *hnode) { struct pool_desc *pool; pool = cfs_hlist_entry(hnode, struct pool_desc, pool_hash); - return (pool->pool_name); + return pool->pool_name; } +/** + * Check if the specified hash key matches the hash node. + * + * This is needed in case there is a hash key collision, allowing the hash + * table lookup/iteration to distinguish between the two entries. + * + * \param[in] key key (pool name) being searched for + * \param[in] compared current entry being compared + * + * \retval 0 if \a key is the same as the key of \a compared + * \retval 1 if \a key is different from the key of \a compared + */ static int pool_hashkey_keycmp(const void *key, cfs_hlist_node_t *compared_hnode) { char *pool_name; @@ -121,6 +199,17 @@ static int pool_hashkey_keycmp(const void *key, cfs_hlist_node_t *compared_hnode return !strncmp(pool_name, pool->pool_name, LOV_MAXPOOLNAME); } +/** + * Return the actual pool data structure from the hash table entry. + * + * Once the hash table entry is found, extract the pool data from it. + * The return type of this function is void * because it needs to be + * assigned to the generic hash operations table. + * + * \param[in] hnode hash table entry + * + * \retval struct pool_desc for the specified \a hnode + */ static void *pool_hashobject(cfs_hlist_node_t *hnode) { return cfs_hlist_entry(hnode, struct pool_desc, pool_hash); @@ -131,48 +220,57 @@ static void pool_hashrefcount_get(cfs_hash_t *hs, cfs_hlist_node_t *hnode) struct pool_desc *pool; pool = cfs_hlist_entry(hnode, struct pool_desc, pool_hash); - lod_pool_getref(pool); + pool_getref(pool); } static void pool_hashrefcount_put_locked(cfs_hash_t *hs, - cfs_hlist_node_t *hnode) + cfs_hlist_node_t *hnode) { struct pool_desc *pool; pool = cfs_hlist_entry(hnode, struct pool_desc, pool_hash); - lod_pool_putref_locked(pool); + pool_putref_locked(pool); } cfs_hash_ops_t pool_hash_operations = { - .hs_hash = pool_hashfn, - .hs_key = pool_key, - .hs_keycmp = pool_hashkey_keycmp, - .hs_object = pool_hashobject, - .hs_get = pool_hashrefcount_get, + .hs_hash = pool_hashfn, + .hs_key = pool_key, + .hs_keycmp = pool_hashkey_keycmp, + .hs_object = pool_hashobject, + .hs_get = pool_hashrefcount_get, .hs_put_locked = pool_hashrefcount_put_locked, }; -#ifdef LPROCFS -/* ifdef needed for liblustre support */ -/* - * pool /proc seq_file methods - */ /* - * iterator is used to go through the target pool entries - * index is the current entry index in the lp_array[] array - * index >= pos returned to the seq_file interface - * pos is from 0 to (pool->pool_obds.op_count - 1) + * Methods for /proc seq_file iteration of the defined pools. */ + #define POOL_IT_MAGIC 0xB001CEA0 struct lod_pool_iterator { - int lpi_magic; + int lpi_magic; /* POOL_IT_MAGIC */ int lpi_idx; /* from 0 to pool_tgt_size - 1 */ struct pool_desc *lpi_pool; }; -static void *pool_proc_next(struct seq_file *s, void *v, loff_t *pos) +/** + * Return the next configured target within one pool for seq_file iteration. + * + * Iterator is used to go through the target entries of a single pool + * (i.e. the list of OSTs configured for a named pool). + * lpi_idx is the current target index in the pool's op_array[]. + * + * The return type is a void * because this function is one of the + * struct seq_operations methods and must match the function template. + * + * \param[in] seq /proc sequence file iteration tracking structure + * \param[in] v unused + * \param[in] pos position within iteration; 0 to number of targets - 1 + * + * \retval struct pool_iterator of the next pool descriptor + */ +static void *pool_proc_next(struct seq_file *seq, void *v, loff_t *pos) { - struct lod_pool_iterator *iter = s->private; + struct lod_pool_iterator *iter = seq->private; int prev_idx; LASSERTF(iter->lpi_magic == POOL_IT_MAGIC, "%08X\n", iter->lpi_magic); @@ -196,12 +294,27 @@ static void *pool_proc_next(struct seq_file *s, void *v, loff_t *pos) return iter; } -static void *pool_proc_start(struct seq_file *s, loff_t *pos) +/** + * Start seq_file iteration via /proc for a single pool. + * + * The \a pos parameter may be non-zero, indicating that the iteration + * is starting at some offset in the target list. Use the seq_file + * private field to memorize the iterator so we can free it at stop(). + * Need to restore the private pointer to the pool before freeing it. + * + * \param[in] seq new sequence file structure to initialize + * \param[in] pos initial target number at which to start iteration + * + * \retval initialized pool iterator private structure + * \retval NULL if \a pos exceeds the number of targets in \a pool + * \retval negative error number on failure + */ +static void *pool_proc_start(struct seq_file *seq, loff_t *pos) { - struct pool_desc *pool = s->private; + struct pool_desc *pool = seq->private; struct lod_pool_iterator *iter; - lod_pool_getref(pool); + pool_getref(pool); if ((pool_tgt_count(pool) == 0) || (*pos >= pool_tgt_count(pool))) { /* iter is not created, so stop() has no way to @@ -211,79 +324,105 @@ static void *pool_proc_start(struct seq_file *s, loff_t *pos) } OBD_ALLOC_PTR(iter); - if (!iter) + if (iter == NULL) return ERR_PTR(-ENOMEM); iter->lpi_magic = POOL_IT_MAGIC; iter->lpi_pool = pool; iter->lpi_idx = 0; - /* we use seq_file private field to memorized iterator so - * we can free it at stop() */ - /* /!\ do not forget to restore it to pool before freeing it */ - s->private = iter; + seq->private = iter; if (*pos > 0) { loff_t i; void *ptr; i = 0; do { - ptr = pool_proc_next(s, &iter, &i); + ptr = pool_proc_next(seq, &iter, &i); } while ((i < *pos) && (ptr != NULL)); + return ptr; } + return iter; } -static void pool_proc_stop(struct seq_file *s, void *v) +/** + * Finish seq_file iteration for a single pool. + * + * Once iteration has been completed, the pool_iterator struct must be + * freed, and the seq_file private pointer restored to the pool, as it + * was initially when pool_proc_start() was called. + * + * In some cases the stop() method may be called 2 times, without calling + * the start() method (see seq_read() from fs/seq_file.c). We have to free + * the private iterator struct only if seq->private points to the iterator. + * + * \param[in] seq sequence file structure to clean up + * \param[in] v (unused) + */ +static void pool_proc_stop(struct seq_file *seq, void *v) { - struct lod_pool_iterator *iter = s->private; - - /* in some cases stop() method is called 2 times, without - * calling start() method (see seq_read() from fs/seq_file.c) - * we have to free only if s->private is an iterator */ - if (iter != NULL && (iter->lpi_magic == POOL_IT_MAGIC)) { - /* we restore s->private so next call to pool_proc_start() - * will work */ - s->private = iter->lpi_pool; + struct lod_pool_iterator *iter = seq->private; + + if (iter != NULL && iter->lpi_magic == POOL_IT_MAGIC) { + seq->private = iter->lpi_pool; lod_pool_putref(iter->lpi_pool); OBD_FREE_PTR(iter); } - return; } -static int pool_proc_show(struct seq_file *s, void *v) +/** + * Print out one target entry from the pool for seq_file iteration. + * + * The currently referenced pool target is given by op_array[lpi_idx]. + * + * \param[in] seq new sequence file structure to initialize + * \param[in] v (unused) + */ +static int pool_proc_show(struct seq_file *seq, void *v) { struct lod_pool_iterator *iter = v; - struct lod_tgt_desc *osc_desc; + struct lod_tgt_desc *tgt; LASSERTF(iter->lpi_magic == POOL_IT_MAGIC, "%08X\n", iter->lpi_magic); LASSERT(iter->lpi_pool != NULL); LASSERT(iter->lpi_idx <= pool_tgt_count(iter->lpi_pool)); down_read(&pool_tgt_rw_sem(iter->lpi_pool)); - osc_desc = pool_tgt(iter->lpi_pool, iter->lpi_idx); + tgt = pool_tgt(iter->lpi_pool, iter->lpi_idx); up_read(&pool_tgt_rw_sem(iter->lpi_pool)); - if (osc_desc) - seq_printf(s, "%s\n", obd_uuid2str(&(osc_desc->ltd_uuid))); + if (tgt != NULL) + seq_printf(seq, "%s\n", obd_uuid2str(&(tgt->ltd_uuid))); return 0; } -static struct seq_operations pool_proc_ops = { +static const struct seq_operations pool_proc_ops = { .start = pool_proc_start, .next = pool_proc_next, .stop = pool_proc_stop, .show = pool_proc_show, }; +/** + * Open a new /proc file for seq_file iteration of targets in one pool. + * + * Initialize the seq_file private pointer to reference the pool. + * + * \param inode inode to store iteration state for /proc + * \param file file descriptor to store iteration methods + * + * \retval 0 for success + * \retval negative error number on failure + */ static int pool_proc_open(struct inode *inode, struct file *file) { int rc; rc = seq_open(file, &pool_proc_ops); if (!rc) { - struct seq_file *s = file->private_data; - s->private = PDE_DATA(inode); + struct seq_file *seq = file->private_data; + seq->private = PDE_DATA(inode); } return rc; } @@ -294,13 +433,25 @@ static struct file_operations pool_proc_operations = { .llseek = seq_lseek, .release = seq_release, }; -#endif /* LPROCFS */ +/** + * Dump the pool target list into the Lustre debug log. + * + * This is a debugging function to allow dumping the list of targets + * in \a pool to the Lustre kernel debug log at the given \a level. + * + * This is not currently called by any existing code, but can be called + * from within gdb/crash to display the contents of the pool, or from + * code under development. + * + * \param[in] level Lustre debug level (D_INFO, D_WARN, D_ERROR, etc) + * \param[in] pool pool descriptor to be dumped + */ void lod_dump_pool(int level, struct pool_desc *pool) { int i; - lod_pool_getref(pool); + pool_getref(pool); CDEBUG(level, "pool "LOV_POOLNAMEF" has %d members\n", pool->pool_name, pool->pool_obds.op_count); @@ -318,13 +469,27 @@ void lod_dump_pool(int level, struct pool_desc *pool) lod_pool_putref(pool); } -#define LOD_POOL_INIT_COUNT 2 +/** + * Initialize the pool data structures at startup. + * + * Allocate and initialize the pool data structures with the specified + * array size. If pool count is not specified (\a count == 0), then + * POOL_INIT_COUNT will be used. Allocating a non-zero initial array + * size avoids the need to reallocate as new pools are added. + * + * \param[in] op pool structure + * \param[in] count initial size of the target op_array[] array + * + * \retval 0 indicates successful pool initialization + * \retval negative error number on failure + */ +#define POOL_INIT_COUNT 2 int lod_ost_pool_init(struct ost_pool *op, unsigned int count) { ENTRY; if (count == 0) - count = LOD_POOL_INIT_COUNT; + count = POOL_INIT_COUNT; op->op_array = NULL; op->op_count = 0; init_rwsem(&op->op_rw_sem); @@ -338,7 +503,19 @@ int lod_ost_pool_init(struct ost_pool *op, unsigned int count) return 0; } -/* Caller must hold write op_rwlock */ +/** + * Increase the op_array size to hold more targets in this pool. + * + * The size is increased to at least \a min_count, but may be larger + * for an existing pool since ->op_array[] is growing exponentially. + * Caller must hold write op_rwlock. + * + * \param[in] op pool structure + * \param[in] min_count minimum number of entries to handle + * + * \retval 0 on success + * \retval negative error number on failure. + */ int lod_ost_pool_extend(struct ost_pool *op, unsigned int min_count) { __u32 *new; @@ -359,9 +536,23 @@ int lod_ost_pool_extend(struct ost_pool *op, unsigned int min_count) OBD_FREE(op->op_array, op->op_size * sizeof(op->op_array[0])); op->op_array = new; op->op_size = new_size; + return 0; } +/** + * Add a new target to an existing pool. + * + * Add a new target device to the pool previously created and returned by + * lod_pool_new(). Each target can only be in each pool at most one time. + * + * \param[in] op target pool to add new entry + * \param[in] idx pool index number to add to the \a op array + * \param[in] min_count minimum number of entries to expect in the pool + * + * \retval 0 if target could be added to the pool + * \retval negative error if target \a idx was not added + */ int lod_ost_pool_add(struct ost_pool *op, __u32 idx, unsigned int min_count) { int rc = 0, i; @@ -387,6 +578,20 @@ out: return rc; } +/** + * Remove an existing pool from the system. + * + * The specified pool must have previously been allocated by + * lod_pool_new() and not have any target members in the pool. + * If the removed target is not the last, compact the array + * to remove empty spaces. + * + * \param[in] op pointer to the original data structure + * \param[in] idx target index to be removed + * + * \retval 0 on success + * \retval negative error number on failure + */ int lod_ost_pool_remove(struct ost_pool *op, __u32 idx) { int i; @@ -397,7 +602,8 @@ int lod_ost_pool_remove(struct ost_pool *op, __u32 idx) for (i = 0; i < op->op_count; i++) { if (op->op_array[i] == idx) { memmove(&op->op_array[i], &op->op_array[i + 1], - (op->op_count - i - 1) * sizeof(op->op_array[0])); + (op->op_count - i - 1) * + sizeof(op->op_array[0])); op->op_count--; up_write(&op->op_rw_sem); EXIT; @@ -409,6 +615,17 @@ int lod_ost_pool_remove(struct ost_pool *op, __u32 idx) RETURN(-EINVAL); } +/** + * Free the pool after it was emptied and removed from /proc. + * + * Note that all of the child/target entries referenced by this pool + * must have been removed by lod_ost_pool_remove() before it can be + * deleted from memory. + * + * \param[in] op pool to be freed. + * + * \retval 0 on success or if pool was already freed + */ int lod_ost_pool_free(struct ost_pool *op) { ENTRY; @@ -427,6 +644,20 @@ int lod_ost_pool_free(struct ost_pool *op) RETURN(0); } +/** + * Allocate a new pool for the specified device. + * + * Allocate a new pool_desc structure for the specified \a new_pool + * device to create a pool with the given \a poolname. The new pool + * structure is created with a single reference, and is freed when the + * reference count drops to zero. + * + * \param[in] obd Lustre OBD device on which to add a pool iterator + * \param[in] poolname the name of the pool to be created + * + * \retval 0 in case of success + * \retval negative error code in case of error + */ int lod_pool_new(struct obd_device *obd, char *poolname) { struct lod_device *lod = lu2lod_dev(obd->obd_lu_dev); @@ -443,9 +674,6 @@ int lod_pool_new(struct obd_device *obd, char *poolname) strlcpy(new_pool->pool_name, poolname, sizeof(new_pool->pool_name)); new_pool->pool_lobd = obd; - /* ref count init to 1 because when created a pool is always used - * up to deletion - */ atomic_set(&new_pool->pool_refcount, 1); rc = lod_ost_pool_init(&new_pool->pool_obds, 0); if (rc) @@ -459,7 +687,7 @@ int lod_pool_new(struct obd_device *obd, char *poolname) INIT_HLIST_NODE(&new_pool->pool_hash); #ifdef LPROCFS - lod_pool_getref(new_pool); + pool_getref(new_pool); new_pool->pool_proc_entry = lprocfs_add_simple(lod->lod_pool_proc_entry, poolname, #ifndef HAVE_ONLY_PROCFS_SEQ @@ -508,6 +736,15 @@ out_free_pool_obds: return rc; } +/** + * Remove the named pool from the OBD device. + * + * \param[in] obd OBD device on which pool was previously created + * \param[in] poolname name of pool to remove from \a obd + * + * \retval 0 on successfully removing the pool + * \retval negative error numbers for failures + */ int lod_pool_del(struct obd_device *obd, char *poolname) { struct lod_device *lod = lu2lod_dev(obd->obd_lu_dev); @@ -536,14 +773,25 @@ int lod_pool_del(struct obd_device *obd, char *poolname) RETURN(0); } - +/** + * Add a single target device to the named pool. + * + * Add the target specified by \a ostname to the specified \a poolname. + * + * \param[in] obd OBD device on which to add the pool + * \param[in] poolname name of the pool to which to add the target \a ostname + * \param[in] ostname name of the target device to be added + * + * \retval 0 if \a ostname was (previously) added to the named pool + * \retval negative error number on failure + */ int lod_pool_add(struct obd_device *obd, char *poolname, char *ostname) { - struct lod_device *lod = lu2lod_dev(obd->obd_lu_dev); - struct obd_uuid ost_uuid; - struct pool_desc *pool; - unsigned int idx; - int rc = -EINVAL; + struct lod_device *lod = lu2lod_dev(obd->obd_lu_dev); + struct obd_uuid ost_uuid; + struct pool_desc *pool; + unsigned int idx; + int rc = -EINVAL; ENTRY; pool = cfs_hash_lookup(lod->lod_pools_hash_body, poolname); @@ -580,13 +828,27 @@ out: return rc; } +/** + * Remove the named target from the specified pool. + * + * Remove one target named \a ostname from \a poolname. The \a ostname + * is searched for in the lod_device lod_ost_bitmap array, to ensure the + * specified name actually exists in the pool. + * + * \param[in] obd OBD device from which to remove \a poolname + * \param[in] poolname name of the pool to be changed + * \param[in] ostname name of the target to remove from \a poolname + * + * \retval 0 on successfully removing \a ostname from the pool + * \retval negative number on error (e.g. \a ostname not in pool) + */ int lod_pool_remove(struct obd_device *obd, char *poolname, char *ostname) { - struct lod_device *lod = lu2lod_dev(obd->obd_lu_dev); - struct obd_uuid ost_uuid; - struct pool_desc *pool; - unsigned int idx; - int rc = -EINVAL; + struct lod_device *lod = lu2lod_dev(obd->obd_lu_dev); + struct obd_uuid ost_uuid; + struct pool_desc *pool; + unsigned int idx; + int rc = -EINVAL; ENTRY; pool = cfs_hash_lookup(lod->lod_pools_hash_body, poolname); @@ -596,7 +858,6 @@ int lod_pool_remove(struct obd_device *obd, char *poolname, char *ostname) obd_str2uuid(&ost_uuid, ostname); lod_getref(&lod->lod_ost_descs); - /* search ost in lod array, to get index */ cfs_foreach_bit(lod->lod_ost_bitmap, idx) { if (obd_uuid_equals(&ost_uuid, &OST_TGT(lod, idx)->ltd_uuid)) { rc = 0; @@ -622,16 +883,24 @@ out: return rc; } +/** + * Check if the specified target exists in the pool. + * + * The caller may not have a reference on \a pool if it got the pool without + * calling lod_find_pool() (e.g. directly from the lod pool list) + * + * \param[in] idx Target index to check + * \param[in] pool Pool in which to check if target is added. + * + * \retval 0 successfully found index in \a pool + * \retval negative error if device not found in \a pool + */ int lod_check_index_in_pool(__u32 idx, struct pool_desc *pool) { int i, rc; ENTRY; - /* caller may no have a ref on pool if it got the pool - * without calling lod_find_pool() (e.g. go through the lod pool - * list) - */ - lod_pool_getref(pool); + pool_getref(pool); down_read(&pool_tgt_rw_sem(pool)); @@ -648,6 +917,16 @@ out: return rc; } +/** + * Find the pool descriptor for the specified pool and return it with a + * reference to the caller if found. + * + * \param[in] lod LOD on which the pools are configured + * \param[in] poolname NUL-terminated name of the pool + * + * \retval pointer to pool descriptor on success + * \retval NULL if \a poolname could not be found or poolname is empty + */ struct pool_desc *lod_find_pool(struct lod_device *lod, char *poolname) { struct pool_desc *pool; -- 1.8.3.1