search for: nxdata

Future patches want to allow a filter to pass a single opaque parameter into another framework (such as ext2fs_open) or even spawn a helper thread, which requires that nxdata be stable for the entire life of the connection between .open and .close. Our current approach of creating a stack-allocated nxdata for every call does not play nicely with that scheme, so rework things into using a malloc'd pointer. In fact, if we use struct b_conn as our filter handle, and...

This was previously used as ‘nxdata’ and stored a tuple of ’b->next’ and the real filter handle. However after recent changes we don't need it. We can use ‘b->next’ as nxdata, and the handle is passed to us by the calling functions. Inspired by Eric Blakes observations in this email: https://www.redhat.com/archives/libgu...

With our recent cleanups to nxdata, the only remaining difference between functions like backend_open() and next_open() was the signature (one used void*, the other struct backend *); the API is compatible. All of our filters are in-tree, and we don't promise API/ABI stability, but it is still a lot of files to touch, so the si...

It's confusing to use the same terminology for a single backend as for the linked list of backends. In particular it's often not clear if we're calling the next backend or the whole chain of backends. --- server/internal.h | 14 ++++++++++-- server/connections.c | 20 ++++++++--------- server/locks.c | 2 +- server/main.c

...++++++++++++++++++++++++++++++----- 1 file changed, 52 insertions(+), 6 deletions(-) diff --git a/filters/retry/retry.c b/filters/retry/retry.c index 59e7d4b8..00dbd091 100644 --- a/filters/retry/retry.c +++ b/filters/retry/retry.c @@ -106,6 +106,7 @@ retry_config (nbdkit_next_config *next, void *nxdata, struct retry_handle { int readonly; /* Save original readonly setting. */ + unsigned reopens; }; static void * @@ -123,6 +124,7 @@ retry_open (nbdkit_next_open *next, void *nxdata, int readonly) } h->readonly = readonly; + h->reopens = 0; return h; } @@...

...3..cf8f5246 100644 > --- a/filters/retry/retry.c > +++ b/filters/retry/retry.c > @@ -148,6 +148,17 @@ struct retry_data { > int delay; /* Seconds to wait before retrying. */ > }; > > +static bool > +valid_range (struct nbdkit_next_ops *next_ops, void *nxdata, > + uint32_t count, uint64_t offset, bool is_write, int *err) > +{ > + if ((int64_t) offset + count > next_ops->get_size (nxdata)) { > + *err = is_write ? ENOSPC : EIO; > + return false; > + } > + return true; > +} > + > static bool > d...

....c b/filters/retry/retry.c index 840d7383..cf8f5246 100644 --- a/filters/retry/retry.c +++ b/filters/retry/retry.c @@ -148,6 +148,17 @@ struct retry_data { int delay; /* Seconds to wait before retrying. */ }; +static bool +valid_range (struct nbdkit_next_ops *next_ops, void *nxdata, + uint32_t count, uint64_t offset, bool is_write, int *err) +{ + if ((int64_t) offset + count > next_ops->get_size (nxdata)) { + *err = is_write ? ENOSPC : EIO; + return false; + } + return true; +} + static bool do_retry (struct retry_handle *h, struct retr...

...49,13 +49,13 @@ struct backend_filter { struct nbdkit_filter filter; }; -/* Literally a backend, a connection pointer, and the filter's handle. +/* Literally a backend and the filter's handle. + * * This is the implementation of our handle in .open, and serves as * a stable ‘void *nxdata’ in the filter API. */ -struct b_conn { +struct b_h { struct backend *b; - struct connection *conn; void *handle; }; @@ -186,22 +186,22 @@ filter_config_complete (struct backend *b) static int next_preconnect (void *nxdata, int readonly) { - struct b_conn *b_conn = nxdata; - return...

...Makefile.am @@ -32,4 +32,5 @@ SUBDIRS = \ delay \ - offset + offset \ + partition diff --git a/filters/delay/delay.c b/filters/delay/delay.c index c8d9ef2..66b7e56 100644 --- a/filters/delay/delay.c +++ b/filters/delay/delay.c @@ -121,30 +121,30 @@ delay_config (nbdkit_next_config *next, void *nxdata, /* Read data. */ static int -delay_pread (struct nbdkit_next *next, void *nxdata, +delay_pread (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle, void *buf, uint32_t count, uint64_t offset) { read_delay (); - return next->pread (nxdata, buf, count, offset); +...

v1 was here: https://www.redhat.com/archives/libguestfs/2020-February/msg00081.html v2 replaces struct connection *conn = GET_CONN; with GET_CONN; which sets conn implicitly and asserts that it is non-NULL. If we actually want to test if conn is non-NULL or behave differently, then you must use threadlocal_get_conn() instead, and some existing uses do that. Rich.

...ey (f->backend.next); + return b->next->magic_config_key (b->next); } static int @@ -236,7 +230,7 @@ static int filter_open (struct backend *b, struct connection *conn, int readonly) { struct backend_filter *f = container_of (b, struct backend_filter, backend); - struct b_conn nxdata = { .b = f->backend.next, .conn = conn }; + struct b_conn nxdata = { .b = b->next, .conn = conn }; void *handle; debug ("%s: open readonly=%d", f->name, readonly); @@ -245,24 +239,24 @@ filter_open (struct backend *b, struct connection *conn, int readonly) handle = f...

The third patch is a large but mechanical change which gets rid of passing around struct connection * entirely within the server, preferring instead to reference the connection through thread-local storage. I hope this is a gateway to simplifying other parts of the code. Rich.

...akefile.am | 5 ++++- 8 files changed, 40 insertions(+), 48 deletions(-) diff --git a/filters/cache/cache.c b/filters/cache/cache.c index 6a9966e..b3fef42 100644 --- a/filters/cache/cache.c +++ b/filters/cache/cache.c @@ -209,9 +209,8 @@ cache_get_size (struct nbdkit_next_ops *next_ops, void *nxdata, nbdkit_debug ("cache: underlying file size: %" PRIi64, size); - pthread_mutex_lock (&lock); + ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&lock); r = blk_set_size (size); - pthread_mutex_unlock (&lock); if (r == -1) return -1; @@ -266,9 +265,10 @@ cache_pread (struct...

Based on Rich's review of my v1 that touched only cache.c, I have now tried to bring all three filters with alignment rounding in line with one another. There is definitely room for future improvements once we teach nbdkit to let filters and plugins advertise block sizes, but I'm hoping to get NBD_CMD_CACHE implemented first. Eric Blake (2): blocksize: Process requests in linear order

...arantee, and nbdkit may refuse to use a filter that was compiled +against a different version rather than risk misbehavior. =head1 C<nbdkit-filter.h> @@ -320,11 +325,15 @@ error message and return C<-1>. =head2 C<.pread> int (*pread) (struct nbdkit_next_ops *next_ops, void *nxdata, - void *handle, void *buf, uint32_t count, uint64_t offset); + void *handle, void *buf, uint32_t count, uint64_t offset, + uint32_t flags); This intercepts the plugin C<.pread> method and can be used to read or modify data read by the plugin. +At...

...b/docs/nbdkit-filter.pod index 55dfab1..0f81684 100644 --- a/docs/nbdkit-filter.pod +++ b/docs/nbdkit-filter.pod @@ -413,6 +413,10 @@ cached value. =head2 C<.can_cache> +=head2 C<.init_sparse> + +=head2 C<.init_zero> + int (*can_write) (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle); int (*can_flush) (struct nbdkit_next_ops *next_ops, void *nxdata, @@ -434,6 +438,10 @@ cached value. void *handle); int (*can_cache) (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle); + int (*init_spar...

...*addr, socklen_t *addrlen); extern void nbdkit_shutdown (void); diff --git a/include/nbdkit-filter.h b/include/nbdkit-filter.h index 229a54b4..cec12db7 100644 --- a/include/nbdkit-filter.h +++ b/include/nbdkit-filter.h @@ -65,13 +65,14 @@ typedef int nbdkit_next_config_complete (nbdkit_backend *nxdata); typedef int nbdkit_next_get_ready (nbdkit_backend *nxdata); typedef int nbdkit_next_after_fork (nbdkit_backend *nxdata); typedef int nbdkit_next_preconnect (nbdkit_backend *nxdata, int readonly); -typedef int nbdkit_next_open (nbdkit_backend *nxdata, int readonly); +typedef int nbdkit_next_ope...

...--git a/docs/nbdkit-filter.pod b/docs/nbdkit-filter.pod index b6ed5504..32db0938 100644 --- a/docs/nbdkit-filter.pod +++ b/docs/nbdkit-filter.pod @@ -298,11 +298,18 @@ with an error message and return C<-1>. =head2 C<.get_ready> - int (*get_ready) (nbdkit_next_get_ready *next, void *nxdata); + int (*get_ready) (nbdkit_next_get_ready *next, void *nxdata, + int thread_model); This intercepts the plugin C<.get_ready> method and can be used by the filter to get ready to serve requests. +The C<thread_model> parameter informs the filter about the final +th...

...requests safely, this lock must be held + * when calling any blk_* functions. + */ +static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER; enum cache_mode cache_mode = CACHE_MODE_WRITEBACK; bool cache_on_read = false; @@ -132,6 +138,7 @@ cache_get_size (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle) { int64_t size; + int r; size = next_ops->get_size (nxdata); if (size == -1) @@ -139,7 +146,10 @@ cache_get_size (struct nbdkit_next_ops *next_ops, void *nxdata, nbdkit_debug ("cache: underlying file size: %" PRIi64, size); - if (blk_s...

...75ac2c4c..7ad4a005 100644 --- a/filters/ext2/ext2.c +++ b/filters/ext2/ext2.c @@ -294,6 +294,25 @@ static int ext2_thread_model (void) return NBDKIT_THREAD_MODEL_SERIALIZE_CONNECTIONS; } +/* Description. */ +static const char * +ext2_export_description (struct nbdkit_next_ops *next_ops, void *nxdata, + void *handle) +{ + struct handle *h = handle; + const char *fname = file ?: h->exportname; + const char *slash = fname[0] == '/' ? "" : "/"; + const char *base = next_ops->export_description (nxdata); + CLEANUP_FREE char *desc = NULL...