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authorDavid Howells <dhowells@redhat.com>2021-10-20 14:06:34 +0100
committerDavid Howells <dhowells@redhat.com>2022-01-07 13:40:33 +0000
commit16a96bdf92d5af06f9fa6a01a4b08e2fdfed2e5b (patch)
tree656b9af20d052cbd2687e3b1bfbf40d284105fd5 /fs/fscache
parent1f67e6d0b18853c641d861a671f46a4964a88510 (diff)
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.h3
-rw-r--r--fs/fscache/io.c25
-rw-r--r--fs/fscache/stats.c9
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),