search for: cow_pwrite

...22,7 @@ static struct nbdkit_filter filter = { .can_write = cow_can_write, .can_flush = cow_can_flush, .can_trim = cow_can_trim, + .can_extents = cow_can_extents, .can_fua = cow_can_fua, .pread = cow_pread, .pwrite = cow_pwrite, -- 2.20.1

...blknum++; + } + + /* Unaligned tail */ + if (count) { + assert (block); + ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&lock); + r = blk_read (next_ops, nxdata, blknum, block, err); + if (r == -1) + return -1; + + memcpy (buf, block, count); } return 0; @@ -197,27 +230,29 @@ cow_pwrite (struct nbdkit_next_ops *next_ops, void *nxdata, uint32_t flags, int *err) { CLEANUP_FREE uint8_t *block = NULL; + uint64_t blknum, blkoffs; + int r; - block = malloc (BLKSIZE); - if (block == NULL) { - *err = errno; - nbdkit_error ("malloc: %m"); - return -...

.../* max bytes we can read from this block */ + blknum = offset / BLKSIZE; /* block number */ + blkoffs = offset % BLKSIZE; /* offset within the block */ + n = BLKSIZE - blkoffs; /* max bytes we can read from this block */ if (n > count) n = count; @@ -304,7 +345,7 @@ cow_pwrite (struct nbdkit_next_ops *next_ops, void *nxdata, { uint8_t *block; - block = malloc (blksize); + block = malloc (BLKSIZE); if (block == NULL) { nbdkit_error ("malloc: %m"); return -1; @@ -313,9 +354,9 @@ cow_pwrite (struct nbdkit_next_ops *next_ops, void *nxdata, w...

Eric, you'll probably find the design "interesting" ... It does work, for me at least. Rich.

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

...s we can read from this block */ + if (n > count) + n = count; + + if (blk_read (next_ops, nxdata, blknum) == -1) + return -1; + + memcpy (buf, &block[blkoffs], n); + + buf += n; + count -= n; + offset += n; + } + + return 0; +} + +/* Write data. */ +static int +cow_pwrite (struct nbdkit_next_ops *next_ops, void *nxdata, + void *handle, const void *buf, uint32_t count, uint64_t offset) +{ + while (count > 0) { + uint64_t blknum, blkoffs, n; + + blknum = offset / blksize; /* block number */ + blkoffs = offset % blksize; /* offset within the bl...

..._lock (&lock); - r = blk_read (next_ops, nxdata, blknum, block, err); - pthread_mutex_unlock (&lock); + { + ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&lock); + r = blk_read (next_ops, nxdata, blknum, block, err); + } if (r == -1) return -1; @@ -218,13 +218,12 @@ cow_pwrite (struct nbdkit_next_ops *next_ops, void *nxdata, /* Do a read-modify-write operation on the current block. * Hold the lock over the whole operation. */ - pthread_mutex_lock (&lock); + ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&lock); r = blk_read (next_ops, nxdata, blknum,...

...a, if (n > count) n = count; - if (blk_read (next_ops, nxdata, blknum, block) == -1) { + r = blk_read (next_ops, nxdata, blknum, block); + if (r) { free (block); - return -1; + return r; } memcpy (buf, &block[blkoffs], n); @@ -351,6 +353,7 @@ cow_pwrite (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle, const void *buf, uint32_t count, uint64_t offset) { uint8_t *block; + int r; block = malloc (BLKSIZE); if (block == NULL) { @@ -368,14 +371,16 @@ cow_pwrite (struct nbdkit_next_ops *next_ops, void *nxdata,...

I do have a question about whether patch 2 is right, or whether I've exposed a bigger problem in the truncate (and possibly other) filter, but the rest seem fairly straightforward. Eric Blake (4): server: Check for pthread lock failures truncate: Factor out reading real_size under mutex plugins: Check for mutex failures filters: Check for mutex failures filters/cache/cache.c

Here's what I'm currently playing with; I'm not ready to commit anything until I rebase my FUA work on top of this, as I only want to break filter ABI once between releases. Eric Blake (2): backend: Rework internal/filter error return semantics filters: Add log filter TODO | 2 - docs/nbdkit-filter.pod | 84 +++++++-- docs/nbdkit.pod

Since v1: add the blocksize filter, add testsuite coverage of the log filter, several fixes to the log filter based on what adding tests revealed I'm still working on FUA flag support patches on top of this; the patches should all be committed in the same release, as we want to minimize the number of releases that cause a filter ABI/API bump Eric Blake (3): backend: Rework internal/filter

After more than a month since v2 [1], I've finally got my FUA support series polished. This is all of my outstanding patches, even though some of them were originally posted in separate threads from the original FUA post [2], [3] [1] https://www.redhat.com/archives/libguestfs/2018-January/msg00113.html [2] https://www.redhat.com/archives/libguestfs/2018-January/msg00219.html [3]

I'm not sure exactly which version we're up to, but let's say it's version 4. I'm a lot happier with this version: - all filters have been reviewed and changed where I think that's necessary - can_extents is properly defined and implemented now - NBD protocol is followed - I believe it addresses all previous review points where possible The "only" thing

Since v1: - rework .can_cache to be tri-state, with default of no advertisement (ripple effect through other patches) - add a lot more patches in order to round out filter support And in the meantime, Rich pushed NBD_CMD_CACHE support into libnbd, so in theory we now have a way to test cache commands through the entire stack. Eric Blake (24): server: Internal hooks for implementing

This has already been pushed upstream. I am simply posting these here so we have a reference in the mailing list in case we find bugs later (as I'm sure we will - it's a complex patch series). Great thanks to Eric Blake for tireless review on this one. It also seems to have identified a few minor bugs in qemu along the way. Rich.

This is a cover letter to a series of patches being proposed in tandem to four different projects: - nbd: Document a new NBD_CMD_FLAG_FAST_ZERO command flag - qemu: Implement the flag for both clients and server - libnbd: Implement the flag for clients - nbdkit: Implement the flag for servers, including the nbd passthrough client If you want to test the patches together, I've pushed a