diff options
Diffstat (limited to 'module')
| -rw-r--r-- | module/zfs/dbuf.c | 80 |
1 files changed, 37 insertions, 43 deletions
diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c index 43909cd59..f7376875a 100644 --- a/module/zfs/dbuf.c +++ b/module/zfs/dbuf.c @@ -148,7 +148,7 @@ dbuf_stats_t dbuf_stats = { continue; \ } -struct dbuf_hold_impl_data { +typedef struct dbuf_hold_arg { /* Function arguments */ dnode_t *dh_dn; uint8_t dh_level; @@ -163,14 +163,13 @@ struct dbuf_hold_impl_data { blkptr_t *dh_bp; int dh_err; dbuf_dirty_record_t *dh_dr; - int dh_depth; -}; +} dbuf_hold_arg_t; -static void __dbuf_hold_impl_init(struct dbuf_hold_impl_data *dh, - dnode_t *dn, uint8_t level, uint64_t blkid, boolean_t fail_sparse, - boolean_t fail_uncached, - void *tag, dmu_buf_impl_t **dbp, int depth); -static int __dbuf_hold_impl(struct dbuf_hold_impl_data *dh); +static dbuf_hold_arg_t *dbuf_hold_arg_create(dnode_t *dn, uint8_t level, + uint64_t blkid, boolean_t fail_sparse, boolean_t fail_uncached, + void *tag, dmu_buf_impl_t **dbp); +static int dbuf_hold_impl_arg(dbuf_hold_arg_t *dh); +static void dbuf_hold_arg_destroy(dbuf_hold_arg_t *dh); static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx); static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx); @@ -2622,7 +2621,7 @@ dbuf_destroy(dmu_buf_impl_t *db) __attribute__((always_inline)) static inline int dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse, - dmu_buf_impl_t **parentp, blkptr_t **bpp, struct dbuf_hold_impl_data *dh) + dmu_buf_impl_t **parentp, blkptr_t **bpp) { *parentp = NULL; *bpp = NULL; @@ -2676,15 +2675,10 @@ dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse, } else if (level < nlevels-1) { /* this block is referenced from an indirect block */ int err; - if (dh == NULL) { - err = dbuf_hold_impl(dn, level+1, - blkid >> epbs, fail_sparse, FALSE, NULL, parentp); - } else { - __dbuf_hold_impl_init(dh + 1, dn, dh->dh_level + 1, - blkid >> epbs, fail_sparse, FALSE, NULL, - parentp, dh->dh_depth + 1); - err = __dbuf_hold_impl(dh + 1); - } + dbuf_hold_arg_t *dh = dbuf_hold_arg_create(dn, level + 1, + blkid >> epbs, fail_sparse, FALSE, NULL, parentp); + err = dbuf_hold_impl_arg(dh); + dbuf_hold_arg_destroy(dh); if (err) return (err); err = dbuf_read(*parentp, NULL, @@ -3057,15 +3051,15 @@ dbuf_prefetch(dnode_t *dn, int64_t level, uint64_t blkid, zio_priority_t prio, #define DBUF_HOLD_IMPL_MAX_DEPTH 20 /* - * Helper function for __dbuf_hold_impl() to copy a buffer. Handles + * Helper function for dbuf_hold_impl_arg() to copy a buffer. Handles * the case of encrypted, compressed and uncompressed buffers by * allocating the new buffer, respectively, with arc_alloc_raw_buf(), * arc_alloc_compressed_buf() or arc_alloc_buf().* * - * NOTE: Declared noinline to avoid stack bloat in __dbuf_hold_impl(). + * NOTE: Declared noinline to avoid stack bloat in dbuf_hold_impl_arg(). */ noinline static void -dbuf_hold_copy(struct dbuf_hold_impl_data *dh) +dbuf_hold_copy(struct dbuf_hold_arg *dh) { dnode_t *dn = dh->dh_dn; dmu_buf_impl_t *db = dh->dh_db; @@ -3102,9 +3096,8 @@ dbuf_hold_copy(struct dbuf_hold_impl_data *dh) * Note: dn_struct_rwlock must be held. */ static int -__dbuf_hold_impl(struct dbuf_hold_impl_data *dh) +dbuf_hold_impl_arg(struct dbuf_hold_arg *dh) { - ASSERT3S(dh->dh_depth, <, DBUF_HOLD_IMPL_MAX_DEPTH); dh->dh_parent = NULL; ASSERT(dh->dh_blkid != DMU_BONUS_BLKID); @@ -3125,7 +3118,7 @@ __dbuf_hold_impl(struct dbuf_hold_impl_data *dh) ASSERT3P(dh->dh_parent, ==, NULL); dh->dh_err = dbuf_findbp(dh->dh_dn, dh->dh_level, dh->dh_blkid, - dh->dh_fail_sparse, &dh->dh_parent, &dh->dh_bp, dh); + dh->dh_fail_sparse, &dh->dh_parent, &dh->dh_bp); if (dh->dh_fail_sparse) { if (dh->dh_err == 0 && dh->dh_bp && BP_IS_HOLE(dh->dh_bp)) @@ -3207,38 +3200,33 @@ __dbuf_hold_impl(struct dbuf_hold_impl_data *dh) } /* - * The following code preserves the recursive function dbuf_hold_impl() - * but moves the local variables AND function arguments to the heap to - * minimize the stack frame size. Enough space is initially allocated - * on the stack for 20 levels of recursion. + * dbuf_hold_impl_arg() is called recursively, via dbuf_findbp(). There can + * be as many recursive calls as there are levels of on-disk indirect blocks, + * but typically only 0-2 recursive calls. To minimize the stack frame size, + * the recursive function's arguments and "local variables" are allocated on + * the heap as the dbuf_hold_arg_t. */ int dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, boolean_t fail_sparse, boolean_t fail_uncached, void *tag, dmu_buf_impl_t **dbp) { - struct dbuf_hold_impl_data *dh; - int error; + dbuf_hold_arg_t *dh = dbuf_hold_arg_create(dn, level, blkid, + fail_sparse, fail_uncached, tag, dbp); - dh = kmem_alloc(sizeof (struct dbuf_hold_impl_data) * - DBUF_HOLD_IMPL_MAX_DEPTH, KM_SLEEP); - __dbuf_hold_impl_init(dh, dn, level, blkid, fail_sparse, - fail_uncached, tag, dbp, 0); + int error = dbuf_hold_impl_arg(dh); - error = __dbuf_hold_impl(dh); - - kmem_free(dh, sizeof (struct dbuf_hold_impl_data) * - DBUF_HOLD_IMPL_MAX_DEPTH); + dbuf_hold_arg_destroy(dh); return (error); } -static void -__dbuf_hold_impl_init(struct dbuf_hold_impl_data *dh, - dnode_t *dn, uint8_t level, uint64_t blkid, +static dbuf_hold_arg_t * +dbuf_hold_arg_create(dnode_t *dn, uint8_t level, uint64_t blkid, boolean_t fail_sparse, boolean_t fail_uncached, - void *tag, dmu_buf_impl_t **dbp, int depth) + void *tag, dmu_buf_impl_t **dbp) { + dbuf_hold_arg_t *dh = kmem_alloc(sizeof (*dh), KM_SLEEP); dh->dh_dn = dn; dh->dh_level = level; dh->dh_blkid = blkid; @@ -3255,7 +3243,13 @@ __dbuf_hold_impl_init(struct dbuf_hold_impl_data *dh, dh->dh_err = 0; dh->dh_dr = NULL; - dh->dh_depth = depth; + return (dh); +} + +static void +dbuf_hold_arg_destroy(dbuf_hold_arg_t *dh) +{ + kmem_free(dh, sizeof (*dh)); } dmu_buf_impl_t * |