search for: cache_zero

...lock, err); + if (r != -1) { + memcpy (&block[blkoffs], buf, n); + r = blk_write (next_ops, nxdata, blknum, block, flags, err); + } } + else + r = blk_write (next_ops, nxdata, blknum, buf, flags, err); if (r == -1) return -1; @@ -334,6 +345,7 @@ cache_zero (struct nbdkit_next_ops *next_ops, void *nxdata, { CLEANUP_FREE uint8_t *block = NULL; bool need_flush = false; + bool clean = false; block = malloc (blksize); if (block == NULL) { @@ -350,7 +362,7 @@ cache_zero (struct nbdkit_next_ops *next_ops, void *nxdata, } while (count &g...

...ite (next_ops, nxdata, blknum, block, flags, err); } - memcpy (&block[blkoffs], buf, n); - if (blk_write (next_ops, nxdata, blknum, block, flags, err) == -1) { + pthread_mutex_unlock (&lock); + if (r == -1) { free (block); return -1; } @@ -278,6 +297,7 @@ cache_zero (struct nbdkit_next_ops *next_ops, void *nxdata, } while (count > 0) { uint64_t blknum, blkoffs, n; + int r; blknum = offset / BLKSIZE; /* block number */ blkoffs = offset % BLKSIZE; /* offset within the block */ @@ -285,12 +305,17 @@ cache_zero (struct nbdkit_next_ops...

...FOR_CURRENT_SCOPE (&lock); + r = blk_read (next_ops, nxdata, blknum, block, err); + if (r != -1) { + memcpy (block, buf, count); + r = blk_write (next_ops, nxdata, blknum, block, flags, err); + } + if (r == -1) + return -1; } if (need_flush) @@ -333,6 +390,8 @@ cache_zero (struct nbdkit_next_ops *next_ops, void *nxdata, int *err) { CLEANUP_FREE uint8_t *block = NULL; + uint64_t blknum, blkoffs; + int r; bool need_flush = false; block = malloc (blksize); @@ -348,15 +407,13 @@ cache_zero (struct nbdkit_next_ops *next_ops, void *nxdata, f...

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

This adds a cache filter, which works like the COW filter in reverse. For realistic use it needs a bit more work, especially to add limits on the size of the cache, a more sensible cache replacement policy, and perhaps some kind of background worker to write dirty blocks out. Rich.

...k); r = blk_read (next_ops, nxdata, blknum, block, err); if (r != -1) { memcpy (&block[blkoffs], buf, n); r = blk_write (next_ops, nxdata, blknum, block, flags, err); } - pthread_mutex_unlock (&lock); if (r == -1) return -1; @@ -371,13 +370,12 @@ cache_zero (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,...

...return r; } memcpy (&block[blkoffs], buf, n); - if (blk_writeback (next_ops, nxdata, blknum, block) == -1) { + r = blk_writeback (next_ops, nxdata, blknum, block); + if (r) { free (block); - return -1; + return r; } buf += n; @@ -421,6 +428,7 @@ cache_zero (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle, uint32_t count, uint64_t offset, int may_trim) { uint8_t *block; + int r; block = malloc (BLKSIZE); if (block == NULL) { @@ -437,14 +445,16 @@ cache_zero (struct nbdkit_next_ops *next_ops, void *nxdata, if...

...* 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; @@ -278,14 +344,14 @@ cache_zero (struct nbdkit_next_ops *next_ops, void *nxdata, uint8_t *block; bool need_flush = false; - block = malloc (BLKSIZE); + block = malloc (blksize); if (block == NULL) { *err = errno; nbdkit_error ("malloc: %m"); return -1; } - flags &= ~NBDKIT_FLAG_MAY_...

v4: https://www.redhat.com/archives/libguestfs/2019-January/msg00032.html v5: - Now we set the block size at run time. I'd like to say that I was able to test this change, but unfortunately I couldn't find any easy way to create a filesystem on x86-64 with a block size > 4K. Ext4 doesn't support it at all, and XFS doesn't support block size > page size (and I

This patch series enhances the cache filter in a few ways, primarily adding a "cache-on-read" feature (similar to qemu's copyonread); and adding the ability to limit the cache size and the antecedent of that which is having a method to reclaim cache blocks. As the cache is stored as a sparse temporary file, reclaiming cache blocks simply means punching holes in the temporary file.

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

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]

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

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

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