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authorAndrew Morton <akpm@linux-foundation.org>2022-09-09 22:57:41 +0200
committerAndrew Morton <akpm@linux-foundation.org>2022-10-03 23:21:43 +0200
commit5ca14835dc429c09fefb290f60343fe266382760 (patch)
tree72946ee6f4e14a6e359a36ae9451ed7362a69a40 /fs/libfs.c
parentfirmware: google: test spinlock on panic path to avoid lockups (diff)
downloadlinux-5ca14835dc429c09fefb290f60343fe266382760.tar.xz
linux-5ca14835dc429c09fefb290f60343fe266382760.zip
fs: uninline inode_maybe_inc_iversion()
It has many callsites and is large. text data bss dec hex filename 91796 15984 512 108292 1a704 mm/shmem.o-before 91180 15984 512 107676 1a49c mm/shmem.o-after Acked-by: Jeff Layton <jlayton@kernel.org> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/libfs.c')
-rw-r--r--fs/libfs.c46
1 files changed, 46 insertions, 0 deletions
diff --git a/fs/libfs.c b/fs/libfs.c
index 31b0ddf01c31..682d56345a1c 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -15,6 +15,7 @@
#include <linux/mutex.h>
#include <linux/namei.h>
#include <linux/exportfs.h>
+#include <linux/iversion.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h> /* sync_mapping_buffers */
#include <linux/fs_context.h>
@@ -1520,3 +1521,48 @@ void generic_set_encrypted_ci_d_ops(struct dentry *dentry)
#endif
}
EXPORT_SYMBOL(generic_set_encrypted_ci_d_ops);
+
+/**
+ * inode_maybe_inc_iversion - increments i_version
+ * @inode: inode with the i_version that should be updated
+ * @force: increment the counter even if it's not necessary?
+ *
+ * Every time the inode is modified, the i_version field must be seen to have
+ * changed by any observer.
+ *
+ * If "force" is set or the QUERIED flag is set, then ensure that we increment
+ * the value, and clear the queried flag.
+ *
+ * In the common case where neither is set, then we can return "false" without
+ * updating i_version.
+ *
+ * If this function returns false, and no other metadata has changed, then we
+ * can avoid logging the metadata.
+ */
+bool inode_maybe_inc_iversion(struct inode *inode, bool force)
+{
+ u64 cur, new;
+
+ /*
+ * The i_version field is not strictly ordered with any other inode
+ * information, but the legacy inode_inc_iversion code used a spinlock
+ * to serialize increments.
+ *
+ * Here, we add full memory barriers to ensure that any de-facto
+ * ordering with other info is preserved.
+ *
+ * This barrier pairs with the barrier in inode_query_iversion()
+ */
+ smp_mb();
+ cur = inode_peek_iversion_raw(inode);
+ do {
+ /* If flag is clear then we needn't do anything */
+ if (!force && !(cur & I_VERSION_QUERIED))
+ return false;
+
+ /* Since lowest bit is flag, add 2 to avoid it */
+ new = (cur & ~I_VERSION_QUERIED) + I_VERSION_INCREMENT;
+ } while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new));
+ return true;
+}
+EXPORT_SYMBOL(inode_maybe_inc_iversion);