This first patch here is an updated version of Antonios Motakis' original 4-patch set, merged to one patch:
https://lists.gnu.org/archive/html/qemu-devel/2018-02/msg02283.html * Updated to latest git master, specifically to new qht interface. * Merged the original 4 patches to this single patch. Signed-off-by: Christian Schoenebeck <qemu_...@crudebyte.com> --- fsdev/9p-marshal.h | 4 +- hw/9pfs/9p.c | 200 ++++++++++++++++++++++++++++++++++++++++++++++++----- hw/9pfs/9p.h | 21 ++++++ 3 files changed, 204 insertions(+), 21 deletions(-) diff --git a/fsdev/9p-marshal.h b/fsdev/9p-marshal.h index c8823d878f..d1ad3645c4 100644 --- a/fsdev/9p-marshal.h +++ b/fsdev/9p-marshal.h @@ -10,8 +10,8 @@ typedef struct V9fsString typedef struct V9fsQID { int8_t type; - int32_t version; - int64_t path; + uint32_t version; + uint64_t path; } V9fsQID; typedef struct V9fsStat diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index 55821343e5..b9bbdcbaee 100644 --- a/hw/9pfs/9p.c +++ b/hw/9pfs/9p.c @@ -25,6 +25,7 @@ #include "trace.h" #include "migration/blocker.h" #include "sysemu/qtest.h" +#include "qemu/xxhash.h" int open_fd_hw; int total_open_fd; @@ -571,14 +572,135 @@ static void coroutine_fn virtfs_reset(V9fsPDU *pdu) P9_STAT_MODE_NAMED_PIPE | \ P9_STAT_MODE_SOCKET) -/* This is the algorithm from ufs in spfs */ -static void stat_to_qid(const struct stat *stbuf, V9fsQID *qidp) + +/* creative abuse of qemu_xxhash7, which is based on xxhash */ +static uint32_t qpp_hash(QppEntry e) { - size_t size; + return qemu_xxhash7(e.ino_prefix, e.dev, 0, 0, 0); +} + +static uint32_t qpf_hash(QpfEntry e) +{ + return qemu_xxhash7(e.ino, e.dev, 0, 0, 0); +} + +static bool qpp_cmp_func(const void *obj, const void *userp) +{ + const QppEntry *e1 = obj, *e2 = userp; + return (e1->dev == e2->dev) && (e1->ino_prefix == e2->ino_prefix); +} + +static bool qpf_cmp_func(const void *obj, const void *userp) +{ + const QpfEntry *e1 = obj, *e2 = userp; + return (e1->dev == e2->dev) && (e1->ino == e2->ino); +} + +static void qp_table_remove(void *p, uint32_t h, void *up) +{ + g_free(p); +} + +static void qp_table_destroy(struct qht *ht) +{ + qht_iter(ht, qp_table_remove, NULL); + qht_destroy(ht); +} + +static int qid_path_fullmap(V9fsPDU *pdu, const struct stat *stbuf, + uint64_t *path) +{ + QpfEntry lookup = { + .dev = stbuf->st_dev, + .ino = stbuf->st_ino + }, *val; + uint32_t hash = qpf_hash(lookup); + + /* most users won't need the fullmap, so init the table lazily */ + if (!pdu->s->qpf_table.map) { + qht_init(&pdu->s->qpf_table, qpf_cmp_func, 1 << 16, QHT_MODE_AUTO_RESIZE); + } + + val = qht_lookup(&pdu->s->qpf_table, &lookup, hash); + + if (!val) { + if (pdu->s->qp_fullpath_next == 0) { + /* no more files can be mapped :'( */ + return -ENFILE; + } + + val = g_malloc0(sizeof(QppEntry)); + if (!val) { + return -ENOMEM; + } + *val = lookup; + + /* new unique inode and device combo */ + val->path = pdu->s->qp_fullpath_next++; + pdu->s->qp_fullpath_next &= QPATH_INO_MASK; + qht_insert(&pdu->s->qpf_table, val, hash, NULL); + } + + *path = val->path; + return 0; +} + +/* stat_to_qid needs to map inode number (64 bits) and device id (32 bits) + * to a unique QID path (64 bits). To avoid having to map and keep track + * of up to 2^64 objects, we map only the 16 highest bits of the inode plus + * the device id to the 16 highest bits of the QID path. The 48 lowest bits + * of the QID path equal to the lowest bits of the inode number. + * + * This takes advantage of the fact that inode number are usually not + * random but allocated sequentially, so we have fewer items to keep + * track of. + */ +static int qid_path_prefixmap(V9fsPDU *pdu, const struct stat *stbuf, + uint64_t *path) +{ + QppEntry lookup = { + .dev = stbuf->st_dev, + .ino_prefix = (uint16_t) (stbuf->st_ino >> 48) + }, *val; + uint32_t hash = qpp_hash(lookup); + + val = qht_lookup(&pdu->s->qpp_table, &lookup, hash); + + if (!val) { + if (pdu->s->qp_prefix_next == 0) { + /* we ran out of prefixes */ + return -ENFILE; + } + + val = g_malloc0(sizeof(QppEntry)); + if (!val) { + return -ENOMEM; + } + *val = lookup; + + /* new unique inode prefix and device combo */ + val->qp_prefix = pdu->s->qp_prefix_next++; + qht_insert(&pdu->s->qpp_table, val, hash, NULL); + } + + *path = ((uint64_t)val->qp_prefix << 48) | (stbuf->st_ino & QPATH_INO_MASK); + return 0; +} + +static int stat_to_qid(V9fsPDU *pdu, const struct stat *stbuf, V9fsQID *qidp) +{ + int err; + + /* map inode+device to qid path (fast path) */ + err = qid_path_prefixmap(pdu, stbuf, &qidp->path); + if (err == -ENFILE) { + /* fast path didn't work, fal back to full map */ + err = qid_path_fullmap(pdu, stbuf, &qidp->path); + } + if (err) { + return err; + } - memset(&qidp->path, 0, sizeof(qidp->path)); - size = MIN(sizeof(stbuf->st_ino), sizeof(qidp->path)); - memcpy(&qidp->path, &stbuf->st_ino, size); qidp->version = stbuf->st_mtime ^ (stbuf->st_size << 8); qidp->type = 0; if (S_ISDIR(stbuf->st_mode)) { @@ -587,6 +709,8 @@ static void stat_to_qid(const struct stat *stbuf, V9fsQID *qidp) if (S_ISLNK(stbuf->st_mode)) { qidp->type |= P9_QID_TYPE_SYMLINK; } + + return 0; } static int coroutine_fn fid_to_qid(V9fsPDU *pdu, V9fsFidState *fidp, @@ -599,7 +723,10 @@ static int coroutine_fn fid_to_qid(V9fsPDU *pdu, V9fsFidState *fidp, if (err < 0) { return err; } - stat_to_qid(&stbuf, qidp); + err = stat_to_qid(pdu, &stbuf, qidp); + if (err < 0) { + return err; + } return 0; } @@ -830,7 +957,10 @@ static int coroutine_fn stat_to_v9stat(V9fsPDU *pdu, V9fsPath *path, memset(v9stat, 0, sizeof(*v9stat)); - stat_to_qid(stbuf, &v9stat->qid); + err = stat_to_qid(pdu, stbuf, &v9stat->qid); + if (err < 0) { + return err; + } v9stat->mode = stat_to_v9mode(stbuf); v9stat->atime = stbuf->st_atime; v9stat->mtime = stbuf->st_mtime; @@ -891,7 +1021,7 @@ static int coroutine_fn stat_to_v9stat(V9fsPDU *pdu, V9fsPath *path, #define P9_STATS_ALL 0x00003fffULL /* Mask for All fields above */ -static void stat_to_v9stat_dotl(V9fsState *s, const struct stat *stbuf, +static int stat_to_v9stat_dotl(V9fsPDU *pdu, const struct stat *stbuf, V9fsStatDotl *v9lstat) { memset(v9lstat, 0, sizeof(*v9lstat)); @@ -913,7 +1043,7 @@ static void stat_to_v9stat_dotl(V9fsState *s, const struct stat *stbuf, /* Currently we only support BASIC fields in stat */ v9lstat->st_result_mask = P9_STATS_BASIC; - stat_to_qid(stbuf, &v9lstat->qid); + return stat_to_qid(pdu, stbuf, &v9lstat->qid); } static void print_sg(struct iovec *sg, int cnt) @@ -1115,7 +1245,6 @@ static void coroutine_fn v9fs_getattr(void *opaque) uint64_t request_mask; V9fsStatDotl v9stat_dotl; V9fsPDU *pdu = opaque; - V9fsState *s = pdu->s; retval = pdu_unmarshal(pdu, offset, "dq", &fid, &request_mask); if (retval < 0) { @@ -1136,7 +1265,10 @@ static void coroutine_fn v9fs_getattr(void *opaque) if (retval < 0) { goto out; } - stat_to_v9stat_dotl(s, &stbuf, &v9stat_dotl); + retval = stat_to_v9stat_dotl(pdu, &stbuf, &v9stat_dotl); + if (retval < 0) { + goto out; + } /* fill st_gen if requested and supported by underlying fs */ if (request_mask & P9_STATS_GEN) { @@ -1381,7 +1513,10 @@ static void coroutine_fn v9fs_walk(void *opaque) if (err < 0) { goto out; } - stat_to_qid(&stbuf, &qid); + err = stat_to_qid(pdu, &stbuf, &qid); + if (err < 0) { + goto out; + } v9fs_path_copy(&dpath, &path); } memcpy(&qids[name_idx], &qid, sizeof(qid)); @@ -1483,7 +1618,10 @@ static void coroutine_fn v9fs_open(void *opaque) if (err < 0) { goto out; } - stat_to_qid(&stbuf, &qid); + err = stat_to_qid(pdu, &stbuf, &qid); + if (err < 0) { + goto out; + } if (S_ISDIR(stbuf.st_mode)) { err = v9fs_co_opendir(pdu, fidp); if (err < 0) { @@ -1593,7 +1731,10 @@ static void coroutine_fn v9fs_lcreate(void *opaque) fidp->flags |= FID_NON_RECLAIMABLE; } iounit = get_iounit(pdu, &fidp->path); - stat_to_qid(&stbuf, &qid); + err = stat_to_qid(pdu, &stbuf, &qid); + if (err < 0) { + goto out; + } err = pdu_marshal(pdu, offset, "Qd", &qid, iounit); if (err < 0) { goto out; @@ -2327,7 +2468,10 @@ static void coroutine_fn v9fs_create(void *opaque) } } iounit = get_iounit(pdu, &fidp->path); - stat_to_qid(&stbuf, &qid); + err = stat_to_qid(pdu, &stbuf, &qid); + if (err < 0) { + goto out; + } err = pdu_marshal(pdu, offset, "Qd", &qid, iounit); if (err < 0) { goto out; @@ -2384,7 +2528,10 @@ static void coroutine_fn v9fs_symlink(void *opaque) if (err < 0) { goto out; } - stat_to_qid(&stbuf, &qid); + err = stat_to_qid(pdu, &stbuf, &qid); + if (err < 0) { + goto out; + } err = pdu_marshal(pdu, offset, "Q", &qid); if (err < 0) { goto out; @@ -3064,7 +3211,10 @@ static void coroutine_fn v9fs_mknod(void *opaque) if (err < 0) { goto out; } - stat_to_qid(&stbuf, &qid); + err = stat_to_qid(pdu, &stbuf, &qid); + if (err < 0) { + goto out; + } err = pdu_marshal(pdu, offset, "Q", &qid); if (err < 0) { goto out; @@ -3222,7 +3372,10 @@ static void coroutine_fn v9fs_mkdir(void *opaque) if (err < 0) { goto out; } - stat_to_qid(&stbuf, &qid); + err = stat_to_qid(pdu, &stbuf, &qid); + if (err < 0) { + goto out; + } err = pdu_marshal(pdu, offset, "Q", &qid); if (err < 0) { goto out; @@ -3633,6 +3786,11 @@ int v9fs_device_realize_common(V9fsState *s, const V9fsTransport *t, goto out; } + /* QID path hash table. 1 entry ought to be enough for anybody ;) */ + qht_init(&s->qpp_table, qpp_cmp_func, 1, QHT_MODE_AUTO_RESIZE); + s->qp_prefix_next = 1; /* reserve 0 to detect overflow */ + s->qp_fullpath_next = 1; + s->ctx.fst = &fse->fst; fsdev_throttle_init(s->ctx.fst); @@ -3646,6 +3804,8 @@ out: } g_free(s->tag); g_free(s->ctx.fs_root); + qp_table_destroy(&s->qpp_table); + qp_table_destroy(&s->qpf_table); v9fs_path_free(&path); } return rc; @@ -3658,6 +3818,8 @@ void v9fs_device_unrealize_common(V9fsState *s, Error **errp) } fsdev_throttle_cleanup(s->ctx.fst); g_free(s->tag); + qp_table_destroy(&s->qpp_table); + qp_table_destroy(&s->qpf_table); g_free(s->ctx.fs_root); } diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h index 8883761b2c..44112ea97f 100644 --- a/hw/9pfs/9p.h +++ b/hw/9pfs/9p.h @@ -8,6 +8,7 @@ #include "fsdev/9p-iov-marshal.h" #include "qemu/thread.h" #include "qemu/coroutine.h" +#include "qemu/qht.h" enum { P9_TLERROR = 6, @@ -235,6 +236,22 @@ struct V9fsFidState V9fsFidState *rclm_lst; }; +#define QPATH_INO_MASK (((unsigned long)1 << 48) - 1) + +/* QID path prefix entry, see stat_to_qid */ +typedef struct { + dev_t dev; + uint16_t ino_prefix; + uint16_t qp_prefix; +} QppEntry; + +/* QID path full entry, as above */ +typedef struct { + dev_t dev; + ino_t ino; + uint64_t path; +} QpfEntry; + struct V9fsState { QLIST_HEAD(, V9fsPDU) free_list; @@ -256,6 +273,10 @@ struct V9fsState Error *migration_blocker; V9fsConf fsconf; V9fsQID root_qid; + struct qht qpp_table; + struct qht qpf_table; + uint16_t qp_prefix_next; + uint64_t qp_fullpath_next; }; /* 9p2000.L open flags */ -- 2.11.0
