Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com> --- hw/9pfs/virtio-9p.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++++-- 1 files changed, 95 insertions(+), 4 deletions(-)
diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c index a9f52c6..811ac38 100644 --- a/hw/9pfs/virtio-9p.c +++ b/hw/9pfs/virtio-9p.c @@ -20,6 +20,7 @@ #include "virtio-9p-xattr.h" int debug_9p_pdu; +static void v9fs_reclaim_fd(V9fsState *s); enum { Oread = 0x00, @@ -107,7 +108,12 @@ static int v9fs_do_closedir(V9fsState *s, DIR *dir) static int v9fs_do_open(V9fsState *s, V9fsString *path, int flags) { - return s->ops->open(&s->ctx, path->data, flags); + int fd; + fd = s->ops->open(&s->ctx, path->data, flags); + if (fd > P9_FD_RECLAIM_THRES) { + v9fs_reclaim_fd(s); + } + return fd; } static DIR *v9fs_do_opendir(V9fsState *s, V9fsString *path) @@ -188,6 +194,7 @@ static int v9fs_do_fstat(V9fsState *s, int fd, struct stat *stbuf) static int v9fs_do_open2(V9fsState *s, char *fullname, uid_t uid, gid_t gid, int flags, int mode) { + int fd; FsCred cred; cred_init(&cred); @@ -196,7 +203,11 @@ static int v9fs_do_open2(V9fsState *s, char *fullname, uid_t uid, gid_t gid, cred.fc_mode = mode & 07777; flags = flags; - return s->ops->open2(&s->ctx, fullname, flags, &cred); + fd = s->ops->open2(&s->ctx, fullname, flags, &cred); + if (fd > P9_FD_RECLAIM_THRES) { + v9fs_reclaim_fd(s); + } + return fd; } static int v9fs_do_symlink(V9fsState *s, V9fsFidState *fidp, @@ -434,6 +445,23 @@ static V9fsFidState *lookup_fid(V9fsState *s, int32_t fid) for (f = s->fid_list; f; f = f->next) { if (f->fid == fid) { + /* + * check whether we need to reopen the + * file. We might have closed the fd + * while trying to free up some file + * descriptors. + */ + if (f->fsmap.fid_type == P9_FID_FILE) { + /* FIXME!! should we remember the open flags ?*/ + if (f->fsmap.fs.fd == -1) { + f->fsmap.fs.fd = v9fs_do_open(s, &f->fsmap.path, O_RDWR); + } + } + /* + * Mark the fid as referenced so that the LRU + * reclaim won't close the file descriptor + */ + f->fsmap.flags |= FID_REFERENCED; return f; } } @@ -461,6 +489,62 @@ static V9fsFidState *alloc_fid(V9fsState *s, int32_t fid) return f; } +static void v9fs_reclaim_fd(V9fsState *s) +{ + int reclaim_count = 0; + V9fsFidState *f; + + for (f = s->fid_list; f; f = f->next) { + /* + * Unlink fids cannot be reclaimed. Check + * for them and skip them + */ + if (f->fsmap.flags & FID_NON_RECLAIMABLE) { + continue; + } + /* + * if it is a recently referenced fid + * we leave the fid untouched and clear the + * reference bit. We come back to it later + * in the next iteration. (a simple LRU without + * moving list elements around) + */ + if (f->fsmap.flags & FID_REFERENCED) { + f->fsmap.flags &= ~FID_REFERENCED; + continue; + } + /* + * reclaim fd, by closing the file descriptors + */ + if (f->fsmap.fid_type == P9_FID_FILE) { + if (f->fsmap.fs.fd != -1) { + v9fs_do_close(s, f->fsmap.fs.fd); + f->fsmap.fs.fd = -1; + reclaim_count++; + } + } + if (reclaim_count >= P9_FD_RECLAIM_THRES/2) { + break; + } + } +} + +static void v9fs_mark_fids_unreclaim(V9fsState *s, V9fsString *str) +{ + V9fsFidState *fidp; + for (fidp = s->fid_list; fidp; fidp = fidp->next) { + if (!strcmp(fidp->fsmap.path.data, str->data)) { + /* Mark the fid non reclaimable. */ + fidp->fsmap.flags |= FID_NON_RECLAIMABLE; + /* reopen the file if already closed */ + if (fidp->fsmap.fs.fd == -1) { + fidp->fsmap.fs.fd = v9fs_do_open(s, &fidp->fsmap.path, O_RDWR); + } + } + } +} + + static int v9fs_xattr_fid_clunk(V9fsState *s, V9fsFidState *fidp) { int retval = 0; @@ -516,7 +600,10 @@ static int free_fid(V9fsState *s, int32_t fid) *fidpp = fidp->next; if (fidp->fsmap.fid_type == P9_FID_FILE) { - v9fs_do_close(s, fidp->fsmap.fs.fd); + /* I we reclaimed the fd no need to close */ + if (fidp->fsmap.fs.fd != -1) { + v9fs_do_close(s, fidp->fsmap.fs.fd); + } } else if (fidp->fsmap.fid_type == P9_FID_DIR) { v9fs_do_closedir(s, fidp->fsmap.fs.dir); } else if (fidp->fsmap.fid_type == P9_FID_XATTR) { @@ -2719,7 +2806,11 @@ static void v9fs_remove(V9fsState *s, V9fsPDU *pdu) err = -EINVAL; goto out; } - + /* + * IF the file is unlinked, we cannot reopen + * the file later. So don't reclaim fd + */ + v9fs_mark_fids_unreclaim(s, &vs->fidp->fsmap.path); err = v9fs_do_remove(s, &vs->fidp->fsmap.path); v9fs_remove_post_remove(s, vs, err); return; -- 1.7.1