ext4: Add support for blocksize < pagesize in dioread_nolock
This patch adds the support for blocksize < pagesize for
dioread_nolock feature.
Since in case of blocksize < pagesize, we can have multiple
small buffers of page as unwritten extents, we need to
maintain a vector of these unwritten extents which needs
the conversion after the IO is complete. Thus, we maintain
a list of tuple <offset, size> pair (io_end_vec) for this &
traverse this list to do the unwritten to written conversion.
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/20191016073711.4141-5-riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 3ccf54a..893913d 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -31,18 +31,56 @@
#include "acl.h"
static struct kmem_cache *io_end_cachep;
+static struct kmem_cache *io_end_vec_cachep;
int __init ext4_init_pageio(void)
{
io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT);
if (io_end_cachep == NULL)
return -ENOMEM;
+
+ io_end_vec_cachep = KMEM_CACHE(ext4_io_end_vec, 0);
+ if (io_end_vec_cachep == NULL) {
+ kmem_cache_destroy(io_end_cachep);
+ return -ENOMEM;
+ }
return 0;
}
void ext4_exit_pageio(void)
{
kmem_cache_destroy(io_end_cachep);
+ kmem_cache_destroy(io_end_vec_cachep);
+}
+
+struct ext4_io_end_vec *ext4_alloc_io_end_vec(ext4_io_end_t *io_end)
+{
+ struct ext4_io_end_vec *io_end_vec;
+
+ io_end_vec = kmem_cache_zalloc(io_end_vec_cachep, GFP_NOFS);
+ if (!io_end_vec)
+ return ERR_PTR(-ENOMEM);
+ INIT_LIST_HEAD(&io_end_vec->list);
+ list_add_tail(&io_end_vec->list, &io_end->list_vec);
+ return io_end_vec;
+}
+
+static void ext4_free_io_end_vec(ext4_io_end_t *io_end)
+{
+ struct ext4_io_end_vec *io_end_vec, *tmp;
+
+ if (list_empty(&io_end->list_vec))
+ return;
+ list_for_each_entry_safe(io_end_vec, tmp, &io_end->list_vec, list) {
+ list_del(&io_end_vec->list);
+ kmem_cache_free(io_end_vec_cachep, io_end_vec);
+ }
+}
+
+struct ext4_io_end_vec *ext4_last_io_end_vec(ext4_io_end_t *io_end)
+{
+ BUG_ON(list_empty(&io_end->list_vec));
+ return list_last_entry(&io_end->list_vec, struct ext4_io_end_vec, list);
}
/*
@@ -125,6 +163,7 @@ static void ext4_release_io_end(ext4_io_end_t *io_end)
ext4_finish_bio(bio);
bio_put(bio);
}
+ ext4_free_io_end_vec(io_end);
kmem_cache_free(io_end_cachep, io_end);
}
@@ -139,8 +178,6 @@ static void ext4_release_io_end(ext4_io_end_t *io_end)
static int ext4_end_io_end(ext4_io_end_t *io_end)
{
struct inode *inode = io_end->inode;
- loff_t offset = io_end->offset;
- ssize_t size = io_end->size;
handle_t *handle = io_end->handle;
int ret = 0;
@@ -154,8 +191,7 @@ static int ext4_end_io_end(ext4_io_end_t *io_end)
ext4_msg(inode->i_sb, KERN_EMERG,
"failed to convert unwritten extents to written "
"extents -- potential data loss! "
- "(inode %lu, offset %llu, size %zd, error %d)",
- inode->i_ino, offset, size, ret);
+ "(inode %lu, error %d)", inode->i_ino, ret);
}
ext4_clear_io_unwritten_flag(io_end);
ext4_release_io_end(io_end);
@@ -247,6 +283,7 @@ ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)
if (io_end) {
io_end->inode = inode;
INIT_LIST_HEAD(&io_end->list);
+ INIT_LIST_HEAD(&io_end->list_vec);
atomic_set(&io_end->count, 1);
}
return io_end;
@@ -255,7 +292,8 @@ ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)
void ext4_put_io_end_defer(ext4_io_end_t *io_end)
{
if (atomic_dec_and_test(&io_end->count)) {
- if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) || !io_end->size) {
+ if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) ||
+ list_empty(&io_end->list_vec)) {
ext4_release_io_end(io_end);
return;
}
@@ -307,10 +345,8 @@ static void ext4_end_bio(struct bio *bio)
struct inode *inode = io_end->inode;
ext4_warning(inode->i_sb, "I/O error %d writing to inode %lu "
- "(offset %llu size %ld starting block %llu)",
+ "starting block %llu)",
bio->bi_status, inode->i_ino,
- (unsigned long long) io_end->offset,
- (long) io_end->size,
(unsigned long long)
bi_sector >> (inode->i_blkbits - 9));
mapping_set_error(inode->i_mapping,