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| author | David Howells <dhowells@redhat.com> | 2021-10-20 14:06:34 +0100 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2022-01-07 13:40:33 +0000 |
| commit | 16a96bdf92d5af06f9fa6a01a4b08e2fdfed2e5b (patch) | |
| tree | 656b9af20d052cbd2687e3b1bfbf40d284105fd5 /fs/fscache | |
| parent | 1f67e6d0b18853c641d861a671f46a4964a88510 (diff) | |
| download | lwn-16a96bdf92d5af06f9fa6a01a4b08e2fdfed2e5b.tar.gz lwn-16a96bdf92d5af06f9fa6a01a4b08e2fdfed2e5b.zip | |
fscache: Provide a function to resize a cookie
Provide a function to change the size of the storage attached to a cookie,
to match the size of the file being cached when it's changed by truncate or
fallocate:
void fscache_resize_cookie(struct fscache_cookie *cookie,
loff_t new_size);
This acts synchronously and is expected to run under the inode lock of the
caller.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819621839.215744.7895597119803515402.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906922387.143852.16394459879816147793.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967128998.1823006.10740669081985775576.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021527861.640689.3466382085497236267.stgit@warthog.procyon.org.uk/ # v4
Diffstat (limited to 'fs/fscache')
| -rw-r--r-- | fs/fscache/internal.h | 3 | ||||
| -rw-r--r-- | fs/fscache/io.c | 25 | ||||
| -rw-r--r-- | fs/fscache/stats.c | 9 |
3 files changed, 35 insertions, 2 deletions
diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h index 017bf3d346a4..f121c21590dc 100644 --- a/fs/fscache/internal.h +++ b/fs/fscache/internal.h @@ -122,6 +122,9 @@ extern atomic_t fscache_n_relinquishes; extern atomic_t fscache_n_relinquishes_retire; extern atomic_t fscache_n_relinquishes_dropped; +extern atomic_t fscache_n_resizes; +extern atomic_t fscache_n_resizes_null; + static inline void fscache_stat(atomic_t *stat) { atomic_inc(stat); diff --git a/fs/fscache/io.c b/fs/fscache/io.c index e9e5d6758ea8..bed7628a5a9d 100644 --- a/fs/fscache/io.c +++ b/fs/fscache/io.c @@ -291,3 +291,28 @@ abandon: term_func(term_func_priv, ret, false); } EXPORT_SYMBOL(__fscache_write_to_cache); + +/* + * Change the size of a backing object. + */ +void __fscache_resize_cookie(struct fscache_cookie *cookie, loff_t new_size) +{ + struct netfs_cache_resources cres; + + trace_fscache_resize(cookie, new_size); + if (fscache_begin_operation(&cres, cookie, FSCACHE_WANT_WRITE, + fscache_access_io_resize) == 0) { + fscache_stat(&fscache_n_resizes); + set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &cookie->flags); + + /* We cannot defer a resize as we need to do it inside the + * netfs's inode lock so that we're serialised with respect to + * writes. + */ + cookie->volume->cache->ops->resize_cookie(&cres, new_size); + fscache_end_operation(&cres); + } else { + fscache_stat(&fscache_n_resizes_null); + } +} +EXPORT_SYMBOL(__fscache_resize_cookie); diff --git a/fs/fscache/stats.c b/fs/fscache/stats.c index db42beb1ba3f..798ee68b3e9d 100644 --- a/fs/fscache/stats.c +++ b/fs/fscache/stats.c @@ -35,6 +35,9 @@ atomic_t fscache_n_relinquishes; atomic_t fscache_n_relinquishes_retire; atomic_t fscache_n_relinquishes_dropped; +atomic_t fscache_n_resizes; +atomic_t fscache_n_resizes_null; + atomic_t fscache_n_read; EXPORT_SYMBOL(fscache_n_read); atomic_t fscache_n_write; @@ -69,8 +72,10 @@ int fscache_stats_show(struct seq_file *m, void *v) seq_printf(m, "Invals : n=%u\n", atomic_read(&fscache_n_invalidates)); - seq_printf(m, "Updates: n=%u\n", - atomic_read(&fscache_n_updates)); + seq_printf(m, "Updates: n=%u rsz=%u rsn=%u\n", + atomic_read(&fscache_n_updates), + atomic_read(&fscache_n_resizes), + atomic_read(&fscache_n_resizes_null)); seq_printf(m, "Relinqs: n=%u rtr=%u drop=%u\n", atomic_read(&fscache_n_relinquishes), |