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Message-ID: <176169812097.1426649.18124588891237135091.stgit@frogsfrogsfrogs>
Date: Tue, 28 Oct 2025 17:56:26 -0700
From: "Darrick J. Wong" <djwong@...nel.org>
To: djwong@...nel.org, miklos@...redi.hu
Cc: joannelkoong@...il.com, bernd@...ernd.com, neal@...pa.dev,
linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH 01/10] fuse: cache iomaps
From: Darrick J. Wong <djwong@...nel.org>
Cache iomaps to a file so that we don't have to upcall the server.
Signed-off-by: "Darrick J. Wong" <djwong@...nel.org>
---
fs/fuse/fuse_i.h | 39 +
fs/fuse/iomap_i.h | 135 ++++
include/uapi/linux/fuse.h | 5
fs/fuse/Makefile | 2
fs/fuse/file_iomap.c | 21 +
fs/fuse/iomap_cache.c | 1629 +++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 1825 insertions(+), 6 deletions(-)
create mode 100644 fs/fuse/iomap_cache.c
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index b4c62e51dec9ea..c38bc8c239665b 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -122,6 +122,24 @@ struct fuse_backing {
struct rcu_head rcu;
};
+#if IS_ENABLED(CONFIG_FUSE_IOMAP)
+/*
+ * File incore extent information, present for each of data & attr forks.
+ */
+struct fuse_ifork {
+ int64_t if_bytes; /* bytes in if_data */
+ void *if_data; /* extent tree root */
+ int if_height; /* height of the extent tree */
+};
+
+struct fuse_iomap_cache {
+ struct fuse_ifork im_read;
+ struct fuse_ifork *im_write;
+ uint64_t im_seq; /* validity counter */
+ struct rw_semaphore im_lock; /* mapping lock */
+};
+#endif
+
/** FUSE inode */
struct fuse_inode {
/** Inode data */
@@ -187,6 +205,9 @@ struct fuse_inode {
spinlock_t ioend_lock;
struct work_struct ioend_work;
struct list_head ioend_list;
+
+ /* cached iomap mappings */
+ struct fuse_iomap_cache cache;
#endif
};
@@ -268,6 +289,11 @@ enum {
FUSE_I_IOMAP,
/* Enable untorn writes */
FUSE_I_ATOMIC,
+ /*
+ * Cache iomaps in the kernel. This is required for any filesystem
+ * that needs to synchronize pagecache write and writeback.
+ */
+ FUSE_I_IOMAP_CACHE,
};
struct fuse_conn;
@@ -1819,6 +1845,18 @@ int fuse_iomap_dev_inval(struct fuse_conn *fc,
const struct fuse_iomap_dev_inval_out *arg);
int fuse_iomap_fadvise(struct file *file, loff_t start, loff_t end, int advice);
+
+static inline bool fuse_inode_caches_iomaps(const struct inode *inode)
+{
+ const struct fuse_inode *fi = get_fuse_inode(inode);
+
+ return test_bit(FUSE_I_IOMAP_CACHE, &fi->state);
+}
+
+enum fuse_iomap_iodir {
+ READ_MAPPING,
+ WRITE_MAPPING,
+};
#else
# define fuse_iomap_enabled(...) (false)
# define fuse_has_iomap(...) (false)
@@ -1846,6 +1884,7 @@ int fuse_iomap_fadvise(struct file *file, loff_t start, loff_t end, int advice);
# define fuse_dev_ioctl_iomap_support(...) (-EOPNOTSUPP)
# define fuse_iomap_dev_inval(...) (-ENOSYS)
# define fuse_iomap_fadvise NULL
+# define fuse_inode_caches_iomaps(...) (false)
#endif
#endif /* _FS_FUSE_I_H */
diff --git a/fs/fuse/iomap_i.h b/fs/fuse/iomap_i.h
index 3615ec76c0dec0..7430cb2d278261 100644
--- a/fs/fuse/iomap_i.h
+++ b/fs/fuse/iomap_i.h
@@ -1,5 +1,9 @@
// SPDX-License-Identifier: GPL-2.0
/*
+ * The fuse_iext code comes from xfs_iext_tree.[ch] and is:
+ * Copyright (c) 2017 Christoph Hellwig.
+ *
+ * Everything else is:
* Copyright (C) 2025 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <djwong@...nel.org>
*/
@@ -40,13 +44,134 @@ while (static_branch_unlikely(&fuse_iomap_debug)) { \
})
#endif /* CONFIG_FUSE_IOMAP_DEBUG */
-enum fuse_iomap_iodir {
- READ_MAPPING,
- WRITE_MAPPING,
-};
-
#define EFSCORRUPTED EUCLEAN
+void fuse_iomap_cache_lock(struct inode *inode);
+void fuse_iomap_cache_unlock(struct inode *inode);
+void fuse_iomap_cache_lock_shared(struct inode *inode);
+void fuse_iomap_cache_unlock_shared(struct inode *inode);
+
+struct fuse_iext_leaf;
+
+struct fuse_iext_cursor {
+ struct fuse_iext_leaf *leaf;
+ int pos;
+};
+
+#define FUSE_IEXT_LEFT_CONTIG (1u << 0)
+#define FUSE_IEXT_RIGHT_CONTIG (1u << 1)
+#define FUSE_IEXT_LEFT_FILLING (1u << 2)
+#define FUSE_IEXT_RIGHT_FILLING (1u << 3)
+#define FUSE_IEXT_LEFT_VALID (1u << 4)
+#define FUSE_IEXT_RIGHT_VALID (1u << 5)
+#define FUSE_IEXT_WRITE_MAPPING (1u << 6)
+
+struct fuse_ifork *fuse_iext_state_to_fork(struct fuse_iomap_cache *ip,
+ unsigned int state);
+
+uint64_t fuse_iext_count(const struct fuse_ifork *ifp);
+void fuse_iext_insert_raw(struct fuse_iomap_cache *ip,
+ struct fuse_ifork *ifp,
+ struct fuse_iext_cursor *cur,
+ const struct fuse_iomap_io *irec);
+void fuse_iext_insert(struct fuse_iomap_cache *,
+ struct fuse_iext_cursor *cur,
+ const struct fuse_iomap_io *, int);
+void fuse_iext_remove(struct fuse_iomap_cache *,
+ struct fuse_iext_cursor *,
+ int);
+void fuse_iext_destroy(struct fuse_ifork *);
+
+bool fuse_iext_lookup_extent(struct fuse_iomap_cache *ip,
+ struct fuse_ifork *ifp, loff_t bno,
+ struct fuse_iext_cursor *cur,
+ struct fuse_iomap_io *gotp);
+bool fuse_iext_lookup_extent_before(struct fuse_iomap_cache *ip,
+ struct fuse_ifork *ifp, loff_t *end,
+ struct fuse_iext_cursor *cur,
+ struct fuse_iomap_io *gotp);
+bool fuse_iext_get_extent(const struct fuse_ifork *ifp,
+ const struct fuse_iext_cursor *cur,
+ struct fuse_iomap_io *gotp);
+void fuse_iext_update_extent(struct fuse_iomap_cache *ip, int state,
+ struct fuse_iext_cursor *cur,
+ struct fuse_iomap_io *gotp);
+
+void fuse_iext_first(struct fuse_ifork *, struct fuse_iext_cursor *);
+void fuse_iext_last(struct fuse_ifork *, struct fuse_iext_cursor *);
+void fuse_iext_next(struct fuse_ifork *, struct fuse_iext_cursor *);
+void fuse_iext_prev(struct fuse_ifork *, struct fuse_iext_cursor *);
+
+static inline bool fuse_iext_next_extent(struct fuse_ifork *ifp,
+ struct fuse_iext_cursor *cur, struct fuse_iomap_io *gotp)
+{
+ fuse_iext_next(ifp, cur);
+ return fuse_iext_get_extent(ifp, cur, gotp);
+}
+
+static inline bool fuse_iext_prev_extent(struct fuse_ifork *ifp,
+ struct fuse_iext_cursor *cur, struct fuse_iomap_io *gotp)
+{
+ fuse_iext_prev(ifp, cur);
+ return fuse_iext_get_extent(ifp, cur, gotp);
+}
+
+/*
+ * Return the extent after cur in gotp without updating the cursor.
+ */
+static inline bool fuse_iext_peek_next_extent(struct fuse_ifork *ifp,
+ struct fuse_iext_cursor *cur, struct fuse_iomap_io *gotp)
+{
+ struct fuse_iext_cursor ncur = *cur;
+
+ fuse_iext_next(ifp, &ncur);
+ return fuse_iext_get_extent(ifp, &ncur, gotp);
+}
+
+/*
+ * Return the extent before cur in gotp without updating the cursor.
+ */
+static inline bool fuse_iext_peek_prev_extent(struct fuse_ifork *ifp,
+ struct fuse_iext_cursor *cur, struct fuse_iomap_io *gotp)
+{
+ struct fuse_iext_cursor ncur = *cur;
+
+ fuse_iext_prev(ifp, &ncur);
+ return fuse_iext_get_extent(ifp, &ncur, gotp);
+}
+
+#define for_each_fuse_iext(ifp, ext, got) \
+ for (fuse_iext_first((ifp), (ext)); \
+ fuse_iext_get_extent((ifp), (ext), (got)); \
+ fuse_iext_next((ifp), (ext)))
+
+static inline uint64_t fuse_iext_read_seq(struct fuse_iomap_cache *ip)
+{
+ return (uint64_t)READ_ONCE(ip->im_seq);
+}
+
+int fuse_iomap_cache_remove(struct inode *inode, enum fuse_iomap_iodir iodir,
+ loff_t off, uint64_t len);
+
+int fuse_iomap_cache_upsert(struct inode *inode, enum fuse_iomap_iodir iodir,
+ const struct fuse_iomap_io *map);
+
+enum fuse_iomap_lookup_result {
+ LOOKUP_HIT,
+ LOOKUP_MISS,
+ LOOKUP_NOFORK,
+};
+
+struct fuse_iomap_lookup {
+ struct fuse_iomap_io map; /* cached mapping */
+ uint64_t validity_cookie; /* used with .iomap_valid() */
+};
+
+enum fuse_iomap_lookup_result
+fuse_iomap_cache_lookup(struct inode *inode, enum fuse_iomap_iodir iodir,
+ loff_t off, uint64_t len,
+ struct fuse_iomap_lookup *mval);
+
#endif /* CONFIG_FUSE_IOMAP */
#endif /* _FS_FUSE_IOMAP_I_H */
diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
index 6061238f08f210..dd87e48ca3105d 100644
--- a/include/uapi/linux/fuse.h
+++ b/include/uapi/linux/fuse.h
@@ -1388,6 +1388,8 @@ struct fuse_uring_cmd_req {
/* fuse-specific mapping type indicating that writes use the read mapping */
#define FUSE_IOMAP_TYPE_PURE_OVERWRITE (255)
+/* fuse-specific mapping type saying the server has populated the cache */
+#define FUSE_IOMAP_TYPE_RETRY_CACHE (254)
#define FUSE_IOMAP_DEV_NULL (0U) /* null device cookie */
@@ -1535,4 +1537,7 @@ struct fuse_iomap_dev_inval_out {
uint64_t length;
};
+/* invalidate all cached iomap mappings up to EOF */
+#define FUSE_IOMAP_INVAL_TO_EOF (~0ULL)
+
#endif /* _LINUX_FUSE_H */
diff --git a/fs/fuse/Makefile b/fs/fuse/Makefile
index 27be39317701d6..e3ed1da6cfb6e7 100644
--- a/fs/fuse/Makefile
+++ b/fs/fuse/Makefile
@@ -18,6 +18,6 @@ fuse-$(CONFIG_FUSE_PASSTHROUGH) += passthrough.o
fuse-$(CONFIG_FUSE_BACKING) += backing.o
fuse-$(CONFIG_SYSCTL) += sysctl.o
fuse-$(CONFIG_FUSE_IO_URING) += dev_uring.o
-fuse-$(CONFIG_FUSE_IOMAP) += file_iomap.o
+fuse-$(CONFIG_FUSE_IOMAP) += file_iomap.o iomap_cache.o
virtiofs-y := virtio_fs.o
diff --git a/fs/fuse/file_iomap.c b/fs/fuse/file_iomap.c
index 53c907dbba2a05..fe1f430686807b 100644
--- a/fs/fuse/file_iomap.c
+++ b/fs/fuse/file_iomap.c
@@ -1130,6 +1130,19 @@ static inline void fuse_inode_clear_atomic(struct inode *inode)
clear_bit(FUSE_I_ATOMIC, &fi->state);
}
+static inline void fuse_iomap_clear_cache(struct inode *inode)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+
+ clear_bit(FUSE_I_IOMAP_CACHE, &fi->state);
+
+ fuse_iext_destroy(&fi->cache.im_read);
+ if (fi->cache.im_write) {
+ fuse_iext_destroy(fi->cache.im_write);
+ kfree(fi->cache.im_write);
+ }
+}
+
void fuse_iomap_init_nonreg_inode(struct inode *inode, unsigned attr_flags)
{
struct fuse_conn *conn = get_fuse_conn(inode);
@@ -1167,6 +1180,8 @@ void fuse_iomap_evict_inode(struct inode *inode)
trace_fuse_iomap_evict_inode(inode);
+ if (fuse_inode_caches_iomaps(inode))
+ fuse_iomap_clear_cache(inode);
if (fuse_inode_has_atomic(inode))
fuse_inode_clear_atomic(inode);
if (fuse_inode_has_iomap(inode))
@@ -1850,6 +1865,12 @@ static inline void fuse_inode_set_iomap(struct inode *inode)
min_order = inode->i_blkbits - PAGE_SHIFT;
mapping_set_folio_min_order(inode->i_mapping, min_order);
+
+ memset(&fi->cache.im_read, 0, sizeof(fi->cache.im_read));
+ fi->cache.im_seq = 0;
+ fi->cache.im_write = NULL;
+
+ init_rwsem(&fi->cache.im_lock);
set_bit(FUSE_I_IOMAP, &fi->state);
}
diff --git a/fs/fuse/iomap_cache.c b/fs/fuse/iomap_cache.c
new file mode 100644
index 00000000000000..d1b0b545b1185e
--- /dev/null
+++ b/fs/fuse/iomap_cache.c
@@ -0,0 +1,1629 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fuse_iext* code adapted from xfs_iext_tree.c:
+ * Copyright (c) 2017 Christoph Hellwig.
+ *
+ * fuse_iomap_cache*lock* code adapted from xfs_inode.c:
+ * Copyright (c) 2000-2006 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ *
+ * Copyright (C) 2025 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@...nel.org>
+ */
+#include "fuse_i.h"
+#include "fuse_trace.h"
+#include "iomap_i.h"
+#include <linux/iomap.h>
+
+/* maximum length of a mapping that we're willing to cache */
+#define FUSE_IOMAP_MAX_LEN ((loff_t)(1ULL << 63))
+
+void fuse_iomap_cache_lock_shared(struct inode *inode)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_iomap_cache *ip = &fi->cache;
+
+ down_read(&ip->im_lock);
+}
+
+void fuse_iomap_cache_unlock_shared(struct inode *inode)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_iomap_cache *ip = &fi->cache;
+
+ up_read(&ip->im_lock);
+}
+
+void fuse_iomap_cache_lock(struct inode *inode)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_iomap_cache *ip = &fi->cache;
+
+ down_write(&ip->im_lock);
+}
+
+void fuse_iomap_cache_unlock(struct inode *inode)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_iomap_cache *ip = &fi->cache;
+
+ up_write(&ip->im_lock);
+}
+
+static inline void assert_cache_locked_shared(struct fuse_iomap_cache *ip)
+{
+ rwsem_assert_held(&ip->im_lock);
+}
+
+static inline void assert_cache_locked(struct fuse_iomap_cache *ip)
+{
+ rwsem_assert_held_write_nolockdep(&ip->im_lock);
+}
+
+static inline struct fuse_inode *FUSE_I(struct fuse_iomap_cache *ip)
+{
+ return container_of(ip, struct fuse_inode, cache);
+}
+
+static inline struct inode *VFS_I(struct fuse_iomap_cache *ip)
+{
+ struct fuse_inode *fi = FUSE_I(ip);
+
+ return &fi->inode;
+}
+
+static inline uint32_t
+fuse_iomap_fork_to_state(const struct fuse_iomap_cache *ip,
+ const struct fuse_ifork *ifp)
+{
+ ASSERT(ifp == ip->im_write || ifp == &ip->im_read);
+
+ if (ifp == ip->im_write)
+ return FUSE_IEXT_WRITE_MAPPING;
+ return 0;
+}
+
+/* Convert bmap state flags to an inode fork. */
+struct fuse_ifork *
+fuse_iext_state_to_fork(
+ struct fuse_iomap_cache *ip,
+ unsigned int state)
+{
+ if (state & FUSE_IEXT_WRITE_MAPPING)
+ return ip->im_write;
+ return &ip->im_read;
+}
+
+/* The internal iext tree record is a struct fuse_iomap_io */
+
+static bool fuse_iext_rec_is_empty(const struct fuse_iomap_io *rec)
+{
+ return rec->length == 0;
+}
+
+static inline void fuse_iext_rec_clear(struct fuse_iomap_io *rec)
+{
+ memset(rec, 0, sizeof(*rec));
+}
+
+static void
+fuse_iext_set(
+ struct fuse_iomap_io *rec,
+ const struct fuse_iomap_io *irec)
+{
+ ASSERT(irec->length > 0);
+
+ *rec = *irec;
+}
+
+static void
+fuse_iext_get(
+ struct fuse_iomap_io *irec,
+ const struct fuse_iomap_io *rec)
+{
+ *irec = *rec;
+}
+
+enum {
+ NODE_SIZE = 256,
+ KEYS_PER_NODE = NODE_SIZE / (sizeof(uint64_t) + sizeof(void *)),
+ RECS_PER_LEAF = (NODE_SIZE - (2 * sizeof(struct fuse_iext_leaf *))) /
+ sizeof(struct fuse_iomap_io),
+};
+
+/*
+ * In-core extent btree block layout:
+ *
+ * There are two types of blocks in the btree: leaf and inner (non-leaf) blocks.
+ *
+ * The leaf blocks are made up by %KEYS_PER_NODE extent records, which each
+ * contain the startoffset, blockcount, startblock and unwritten extent flag.
+ * See above for the exact format, followed by pointers to the previous and next
+ * leaf blocks (if there are any).
+ *
+ * The inner (non-leaf) blocks first contain KEYS_PER_NODE lookup keys, followed
+ * by an equal number of pointers to the btree blocks at the next lower level.
+ *
+ * +-------+-------+-------+-------+-------+----------+----------+
+ * Leaf: | rec 1 | rec 2 | rec 3 | rec 4 | rec N | prev-ptr | next-ptr |
+ * +-------+-------+-------+-------+-------+----------+----------+
+ *
+ * +-------+-------+-------+-------+-------+-------+------+-------+
+ * Inner: | key 1 | key 2 | key 3 | key N | ptr 1 | ptr 2 | ptr3 | ptr N |
+ * +-------+-------+-------+-------+-------+-------+------+-------+
+ */
+struct fuse_iext_node {
+ uint64_t keys[KEYS_PER_NODE];
+#define FUSE_IEXT_KEY_INVALID (1ULL << 63)
+ void *ptrs[KEYS_PER_NODE];
+};
+
+struct fuse_iext_leaf {
+ struct fuse_iomap_io recs[RECS_PER_LEAF];
+ struct fuse_iext_leaf *prev;
+ struct fuse_iext_leaf *next;
+};
+
+inline uint64_t fuse_iext_count(const struct fuse_ifork *ifp)
+{
+ return ifp->if_bytes / sizeof(struct fuse_iomap_io);
+}
+
+static inline int fuse_iext_max_recs(const struct fuse_ifork *ifp)
+{
+ if (ifp->if_height == 1)
+ return fuse_iext_count(ifp);
+ return RECS_PER_LEAF;
+}
+
+static inline struct fuse_iomap_io *cur_rec(const struct fuse_iext_cursor *cur)
+{
+ return &cur->leaf->recs[cur->pos];
+}
+
+static inline bool fuse_iext_valid(const struct fuse_ifork *ifp,
+ const struct fuse_iext_cursor *cur)
+{
+ if (!cur->leaf)
+ return false;
+ if (cur->pos < 0 || cur->pos >= fuse_iext_max_recs(ifp))
+ return false;
+ if (fuse_iext_rec_is_empty(cur_rec(cur)))
+ return false;
+ return true;
+}
+
+static void *
+fuse_iext_find_first_leaf(
+ struct fuse_ifork *ifp)
+{
+ struct fuse_iext_node *node = ifp->if_data;
+ int height;
+
+ if (!ifp->if_height)
+ return NULL;
+
+ for (height = ifp->if_height; height > 1; height--) {
+ node = node->ptrs[0];
+ ASSERT(node);
+ }
+
+ return node;
+}
+
+static void *
+fuse_iext_find_last_leaf(
+ struct fuse_ifork *ifp)
+{
+ struct fuse_iext_node *node = ifp->if_data;
+ int height, i;
+
+ if (!ifp->if_height)
+ return NULL;
+
+ for (height = ifp->if_height; height > 1; height--) {
+ for (i = 1; i < KEYS_PER_NODE; i++)
+ if (!node->ptrs[i])
+ break;
+ node = node->ptrs[i - 1];
+ ASSERT(node);
+ }
+
+ return node;
+}
+
+void
+fuse_iext_first(
+ struct fuse_ifork *ifp,
+ struct fuse_iext_cursor *cur)
+{
+ cur->pos = 0;
+ cur->leaf = fuse_iext_find_first_leaf(ifp);
+}
+
+void
+fuse_iext_last(
+ struct fuse_ifork *ifp,
+ struct fuse_iext_cursor *cur)
+{
+ int i;
+
+ cur->leaf = fuse_iext_find_last_leaf(ifp);
+ if (!cur->leaf) {
+ cur->pos = 0;
+ return;
+ }
+
+ for (i = 1; i < fuse_iext_max_recs(ifp); i++) {
+ if (fuse_iext_rec_is_empty(&cur->leaf->recs[i]))
+ break;
+ }
+ cur->pos = i - 1;
+}
+
+void
+fuse_iext_next(
+ struct fuse_ifork *ifp,
+ struct fuse_iext_cursor *cur)
+{
+ if (!cur->leaf) {
+ ASSERT(cur->pos <= 0 || cur->pos >= RECS_PER_LEAF);
+ fuse_iext_first(ifp, cur);
+ return;
+ }
+
+ ASSERT(cur->pos >= 0);
+ ASSERT(cur->pos < fuse_iext_max_recs(ifp));
+
+ cur->pos++;
+ if (ifp->if_height > 1 && !fuse_iext_valid(ifp, cur) &&
+ cur->leaf->next) {
+ cur->leaf = cur->leaf->next;
+ cur->pos = 0;
+ }
+}
+
+void
+fuse_iext_prev(
+ struct fuse_ifork *ifp,
+ struct fuse_iext_cursor *cur)
+{
+ if (!cur->leaf) {
+ ASSERT(cur->pos <= 0 || cur->pos >= RECS_PER_LEAF);
+ fuse_iext_last(ifp, cur);
+ return;
+ }
+
+ ASSERT(cur->pos >= 0);
+ ASSERT(cur->pos <= RECS_PER_LEAF);
+
+recurse:
+ do {
+ cur->pos--;
+ if (fuse_iext_valid(ifp, cur))
+ return;
+ } while (cur->pos > 0);
+
+ if (ifp->if_height > 1 && cur->leaf->prev) {
+ cur->leaf = cur->leaf->prev;
+ cur->pos = RECS_PER_LEAF;
+ goto recurse;
+ }
+}
+
+static inline int
+fuse_iext_key_cmp(
+ struct fuse_iext_node *node,
+ int n,
+ loff_t offset)
+{
+ if (node->keys[n] > offset)
+ return 1;
+ if (node->keys[n] < offset)
+ return -1;
+ return 0;
+}
+
+static inline int
+fuse_iext_rec_cmp(
+ struct fuse_iomap_io *rec,
+ loff_t offset)
+{
+ if (rec->offset > offset)
+ return 1;
+ if (rec->offset + rec->length <= offset)
+ return -1;
+ return 0;
+}
+
+static void *
+fuse_iext_find_level(
+ struct fuse_ifork *ifp,
+ loff_t offset,
+ int level)
+{
+ struct fuse_iext_node *node = ifp->if_data;
+ int height, i;
+
+ if (!ifp->if_height)
+ return NULL;
+
+ for (height = ifp->if_height; height > level; height--) {
+ for (i = 1; i < KEYS_PER_NODE; i++)
+ if (fuse_iext_key_cmp(node, i, offset) > 0)
+ break;
+
+ node = node->ptrs[i - 1];
+ if (!node)
+ break;
+ }
+
+ return node;
+}
+
+static int
+fuse_iext_node_pos(
+ struct fuse_iext_node *node,
+ loff_t offset)
+{
+ int i;
+
+ for (i = 1; i < KEYS_PER_NODE; i++) {
+ if (fuse_iext_key_cmp(node, i, offset) > 0)
+ break;
+ }
+
+ return i - 1;
+}
+
+static int
+fuse_iext_node_insert_pos(
+ struct fuse_iext_node *node,
+ loff_t offset)
+{
+ int i;
+
+ for (i = 0; i < KEYS_PER_NODE; i++) {
+ if (fuse_iext_key_cmp(node, i, offset) > 0)
+ return i;
+ }
+
+ return KEYS_PER_NODE;
+}
+
+static int
+fuse_iext_node_nr_entries(
+ struct fuse_iext_node *node,
+ int start)
+{
+ int i;
+
+ for (i = start; i < KEYS_PER_NODE; i++) {
+ if (node->keys[i] == FUSE_IEXT_KEY_INVALID)
+ break;
+ }
+
+ return i;
+}
+
+static int
+fuse_iext_leaf_nr_entries(
+ struct fuse_ifork *ifp,
+ struct fuse_iext_leaf *leaf,
+ int start)
+{
+ int i;
+
+ for (i = start; i < fuse_iext_max_recs(ifp); i++) {
+ if (fuse_iext_rec_is_empty(&leaf->recs[i]))
+ break;
+ }
+
+ return i;
+}
+
+static inline uint64_t
+fuse_iext_leaf_key(
+ struct fuse_iext_leaf *leaf,
+ int n)
+{
+ return leaf->recs[n].offset;
+}
+
+static inline void *
+fuse_iext_alloc_node(
+ int size)
+{
+ return kzalloc(size, GFP_KERNEL | __GFP_NOLOCKDEP | __GFP_NOFAIL);
+}
+
+static void
+fuse_iext_grow(
+ struct fuse_ifork *ifp)
+{
+ struct fuse_iext_node *node = fuse_iext_alloc_node(NODE_SIZE);
+ int i;
+
+ if (ifp->if_height == 1) {
+ struct fuse_iext_leaf *prev = ifp->if_data;
+
+ node->keys[0] = fuse_iext_leaf_key(prev, 0);
+ node->ptrs[0] = prev;
+ } else {
+ struct fuse_iext_node *prev = ifp->if_data;
+
+ ASSERT(ifp->if_height > 1);
+
+ node->keys[0] = prev->keys[0];
+ node->ptrs[0] = prev;
+ }
+
+ for (i = 1; i < KEYS_PER_NODE; i++)
+ node->keys[i] = FUSE_IEXT_KEY_INVALID;
+
+ ifp->if_data = node;
+ ifp->if_height++;
+}
+
+static void
+fuse_iext_update_node(
+ struct fuse_ifork *ifp,
+ loff_t old_offset,
+ loff_t new_offset,
+ int level,
+ void *ptr)
+{
+ struct fuse_iext_node *node = ifp->if_data;
+ int height, i;
+
+ for (height = ifp->if_height; height > level; height--) {
+ for (i = 0; i < KEYS_PER_NODE; i++) {
+ if (i > 0 && fuse_iext_key_cmp(node, i, old_offset) > 0)
+ break;
+ if (node->keys[i] == old_offset)
+ node->keys[i] = new_offset;
+ }
+ node = node->ptrs[i - 1];
+ ASSERT(node);
+ }
+
+ ASSERT(node == ptr);
+}
+
+static struct fuse_iext_node *
+fuse_iext_split_node(
+ struct fuse_iext_node **nodep,
+ int *pos,
+ int *nr_entries)
+{
+ struct fuse_iext_node *node = *nodep;
+ struct fuse_iext_node *new = fuse_iext_alloc_node(NODE_SIZE);
+ const int nr_move = KEYS_PER_NODE / 2;
+ int nr_keep = nr_move + (KEYS_PER_NODE & 1);
+ int i = 0;
+
+ /* for sequential append operations just spill over into the new node */
+ if (*pos == KEYS_PER_NODE) {
+ *nodep = new;
+ *pos = 0;
+ *nr_entries = 0;
+ goto done;
+ }
+
+
+ for (i = 0; i < nr_move; i++) {
+ new->keys[i] = node->keys[nr_keep + i];
+ new->ptrs[i] = node->ptrs[nr_keep + i];
+
+ node->keys[nr_keep + i] = FUSE_IEXT_KEY_INVALID;
+ node->ptrs[nr_keep + i] = NULL;
+ }
+
+ if (*pos >= nr_keep) {
+ *nodep = new;
+ *pos -= nr_keep;
+ *nr_entries = nr_move;
+ } else {
+ *nr_entries = nr_keep;
+ }
+done:
+ for (; i < KEYS_PER_NODE; i++)
+ new->keys[i] = FUSE_IEXT_KEY_INVALID;
+ return new;
+}
+
+static void
+fuse_iext_insert_node(
+ struct fuse_ifork *ifp,
+ uint64_t offset,
+ void *ptr,
+ int level)
+{
+ struct fuse_iext_node *node, *new;
+ int i, pos, nr_entries;
+
+again:
+ if (ifp->if_height < level)
+ fuse_iext_grow(ifp);
+
+ new = NULL;
+ node = fuse_iext_find_level(ifp, offset, level);
+ pos = fuse_iext_node_insert_pos(node, offset);
+ nr_entries = fuse_iext_node_nr_entries(node, pos);
+
+ ASSERT(pos >= nr_entries || fuse_iext_key_cmp(node, pos, offset) != 0);
+ ASSERT(nr_entries <= KEYS_PER_NODE);
+
+ if (nr_entries == KEYS_PER_NODE)
+ new = fuse_iext_split_node(&node, &pos, &nr_entries);
+
+ /*
+ * Update the pointers in higher levels if the first entry changes
+ * in an existing node.
+ */
+ if (node != new && pos == 0 && nr_entries > 0)
+ fuse_iext_update_node(ifp, node->keys[0], offset, level, node);
+
+ for (i = nr_entries; i > pos; i--) {
+ node->keys[i] = node->keys[i - 1];
+ node->ptrs[i] = node->ptrs[i - 1];
+ }
+ node->keys[pos] = offset;
+ node->ptrs[pos] = ptr;
+
+ if (new) {
+ offset = new->keys[0];
+ ptr = new;
+ level++;
+ goto again;
+ }
+}
+
+static struct fuse_iext_leaf *
+fuse_iext_split_leaf(
+ struct fuse_iext_cursor *cur,
+ int *nr_entries)
+{
+ struct fuse_iext_leaf *leaf = cur->leaf;
+ struct fuse_iext_leaf *new = fuse_iext_alloc_node(NODE_SIZE);
+ const int nr_move = RECS_PER_LEAF / 2;
+ int nr_keep = nr_move + (RECS_PER_LEAF & 1);
+ int i;
+
+ /* for sequential append operations just spill over into the new node */
+ if (cur->pos == RECS_PER_LEAF) {
+ cur->leaf = new;
+ cur->pos = 0;
+ *nr_entries = 0;
+ goto done;
+ }
+
+ for (i = 0; i < nr_move; i++) {
+ new->recs[i] = leaf->recs[nr_keep + i];
+ fuse_iext_rec_clear(&leaf->recs[nr_keep + i]);
+ }
+
+ if (cur->pos >= nr_keep) {
+ cur->leaf = new;
+ cur->pos -= nr_keep;
+ *nr_entries = nr_move;
+ } else {
+ *nr_entries = nr_keep;
+ }
+done:
+ if (leaf->next)
+ leaf->next->prev = new;
+ new->next = leaf->next;
+ new->prev = leaf;
+ leaf->next = new;
+ return new;
+}
+
+static void
+fuse_iext_alloc_root(
+ struct fuse_ifork *ifp,
+ struct fuse_iext_cursor *cur)
+{
+ ASSERT(ifp->if_bytes == 0);
+
+ ifp->if_data = fuse_iext_alloc_node(sizeof(struct fuse_iomap_io));
+ ifp->if_height = 1;
+
+ /* now that we have a node step into it */
+ cur->leaf = ifp->if_data;
+ cur->pos = 0;
+}
+
+static void
+fuse_iext_realloc_root(
+ struct fuse_ifork *ifp,
+ struct fuse_iext_cursor *cur)
+{
+ int64_t new_size = ifp->if_bytes + sizeof(struct fuse_iomap_io);
+ void *new;
+
+ /* account for the prev/next pointers */
+ if (new_size / sizeof(struct fuse_iomap_io) == RECS_PER_LEAF)
+ new_size = NODE_SIZE;
+
+ new = krealloc(ifp->if_data, new_size,
+ GFP_KERNEL | __GFP_NOLOCKDEP | __GFP_NOFAIL);
+ memset(new + ifp->if_bytes, 0, new_size - ifp->if_bytes);
+ ifp->if_data = new;
+ cur->leaf = new;
+}
+
+/*
+ * Increment the sequence counter on extent tree changes. We use WRITE_ONCE
+ * here to ensure the update to the sequence counter is seen before the
+ * modifications to the extent tree itself take effect.
+ */
+static inline void fuse_iext_inc_seq(struct fuse_iomap_cache *ip)
+{
+ WRITE_ONCE(ip->im_seq, READ_ONCE(ip->im_seq) + 1);
+}
+
+void
+fuse_iext_insert_raw(
+ struct fuse_iomap_cache *ip,
+ struct fuse_ifork *ifp,
+ struct fuse_iext_cursor *cur,
+ const struct fuse_iomap_io *irec)
+{
+ loff_t offset = irec->offset;
+ struct fuse_iext_leaf *new = NULL;
+ int nr_entries, i;
+
+ fuse_iext_inc_seq(ip);
+
+ if (ifp->if_height == 0)
+ fuse_iext_alloc_root(ifp, cur);
+ else if (ifp->if_height == 1)
+ fuse_iext_realloc_root(ifp, cur);
+
+ nr_entries = fuse_iext_leaf_nr_entries(ifp, cur->leaf, cur->pos);
+ ASSERT(nr_entries <= RECS_PER_LEAF);
+ ASSERT(cur->pos >= nr_entries ||
+ fuse_iext_rec_cmp(cur_rec(cur), irec->offset) != 0);
+
+ if (nr_entries == RECS_PER_LEAF)
+ new = fuse_iext_split_leaf(cur, &nr_entries);
+
+ /*
+ * Update the pointers in higher levels if the first entry changes
+ * in an existing node.
+ */
+ if (cur->leaf != new && cur->pos == 0 && nr_entries > 0) {
+ fuse_iext_update_node(ifp, fuse_iext_leaf_key(cur->leaf, 0),
+ offset, 1, cur->leaf);
+ }
+
+ for (i = nr_entries; i > cur->pos; i--)
+ cur->leaf->recs[i] = cur->leaf->recs[i - 1];
+ fuse_iext_set(cur_rec(cur), irec);
+ ifp->if_bytes += sizeof(struct fuse_iomap_io);
+
+ if (new)
+ fuse_iext_insert_node(ifp, fuse_iext_leaf_key(new, 0), new, 2);
+}
+
+void
+fuse_iext_insert(
+ struct fuse_iomap_cache *ip,
+ struct fuse_iext_cursor *cur,
+ const struct fuse_iomap_io *irec,
+ int state)
+{
+ struct fuse_ifork *ifp = fuse_iext_state_to_fork(ip, state);
+
+ fuse_iext_insert_raw(ip, ifp, cur, irec);
+}
+
+static struct fuse_iext_node *
+fuse_iext_rebalance_node(
+ struct fuse_iext_node *parent,
+ int *pos,
+ struct fuse_iext_node *node,
+ int nr_entries)
+{
+ /*
+ * If the neighbouring nodes are completely full, or have different
+ * parents, we might never be able to merge our node, and will only
+ * delete it once the number of entries hits zero.
+ */
+ if (nr_entries == 0)
+ return node;
+
+ if (*pos > 0) {
+ struct fuse_iext_node *prev = parent->ptrs[*pos - 1];
+ int nr_prev = fuse_iext_node_nr_entries(prev, 0), i;
+
+ if (nr_prev + nr_entries <= KEYS_PER_NODE) {
+ for (i = 0; i < nr_entries; i++) {
+ prev->keys[nr_prev + i] = node->keys[i];
+ prev->ptrs[nr_prev + i] = node->ptrs[i];
+ }
+ return node;
+ }
+ }
+
+ if (*pos + 1 < fuse_iext_node_nr_entries(parent, *pos)) {
+ struct fuse_iext_node *next = parent->ptrs[*pos + 1];
+ int nr_next = fuse_iext_node_nr_entries(next, 0), i;
+
+ if (nr_entries + nr_next <= KEYS_PER_NODE) {
+ /*
+ * Merge the next node into this node so that we don't
+ * have to do an additional update of the keys in the
+ * higher levels.
+ */
+ for (i = 0; i < nr_next; i++) {
+ node->keys[nr_entries + i] = next->keys[i];
+ node->ptrs[nr_entries + i] = next->ptrs[i];
+ }
+
+ ++*pos;
+ return next;
+ }
+ }
+
+ return NULL;
+}
+
+static void
+fuse_iext_remove_node(
+ struct fuse_ifork *ifp,
+ loff_t offset,
+ void *victim)
+{
+ struct fuse_iext_node *node, *parent;
+ int level = 2, pos, nr_entries, i;
+
+ ASSERT(level <= ifp->if_height);
+ node = fuse_iext_find_level(ifp, offset, level);
+ pos = fuse_iext_node_pos(node, offset);
+again:
+ ASSERT(node->ptrs[pos]);
+ ASSERT(node->ptrs[pos] == victim);
+ kfree(victim);
+
+ nr_entries = fuse_iext_node_nr_entries(node, pos) - 1;
+ offset = node->keys[0];
+ for (i = pos; i < nr_entries; i++) {
+ node->keys[i] = node->keys[i + 1];
+ node->ptrs[i] = node->ptrs[i + 1];
+ }
+ node->keys[nr_entries] = FUSE_IEXT_KEY_INVALID;
+ node->ptrs[nr_entries] = NULL;
+
+ if (pos == 0 && nr_entries > 0) {
+ fuse_iext_update_node(ifp, offset, node->keys[0], level, node);
+ offset = node->keys[0];
+ }
+
+ if (nr_entries >= KEYS_PER_NODE / 2)
+ return;
+
+ if (level < ifp->if_height) {
+ /*
+ * If we aren't at the root yet try to find a neighbour node to
+ * merge with (or delete the node if it is empty), and then
+ * recurse up to the next level.
+ */
+ level++;
+ parent = fuse_iext_find_level(ifp, offset, level);
+ pos = fuse_iext_node_pos(parent, offset);
+
+ ASSERT(pos != KEYS_PER_NODE);
+ ASSERT(parent->ptrs[pos] == node);
+
+ node = fuse_iext_rebalance_node(parent, &pos, node, nr_entries);
+ if (node) {
+ victim = node;
+ node = parent;
+ goto again;
+ }
+ } else if (nr_entries == 1) {
+ /*
+ * If we are at the root and only one entry is left we can just
+ * free this node and update the root pointer.
+ */
+ ASSERT(node == ifp->if_data);
+ ifp->if_data = node->ptrs[0];
+ ifp->if_height--;
+ kfree(node);
+ }
+}
+
+static void
+fuse_iext_rebalance_leaf(
+ struct fuse_ifork *ifp,
+ struct fuse_iext_cursor *cur,
+ struct fuse_iext_leaf *leaf,
+ loff_t offset,
+ int nr_entries)
+{
+ /*
+ * If the neighbouring nodes are completely full we might never be able
+ * to merge our node, and will only delete it once the number of
+ * entries hits zero.
+ */
+ if (nr_entries == 0)
+ goto remove_node;
+
+ if (leaf->prev) {
+ int nr_prev = fuse_iext_leaf_nr_entries(ifp, leaf->prev, 0), i;
+
+ if (nr_prev + nr_entries <= RECS_PER_LEAF) {
+ for (i = 0; i < nr_entries; i++)
+ leaf->prev->recs[nr_prev + i] = leaf->recs[i];
+
+ if (cur->leaf == leaf) {
+ cur->leaf = leaf->prev;
+ cur->pos += nr_prev;
+ }
+ goto remove_node;
+ }
+ }
+
+ if (leaf->next) {
+ int nr_next = fuse_iext_leaf_nr_entries(ifp, leaf->next, 0), i;
+
+ if (nr_entries + nr_next <= RECS_PER_LEAF) {
+ /*
+ * Merge the next node into this node so that we don't
+ * have to do an additional update of the keys in the
+ * higher levels.
+ */
+ for (i = 0; i < nr_next; i++) {
+ leaf->recs[nr_entries + i] =
+ leaf->next->recs[i];
+ }
+
+ if (cur->leaf == leaf->next) {
+ cur->leaf = leaf;
+ cur->pos += nr_entries;
+ }
+
+ offset = fuse_iext_leaf_key(leaf->next, 0);
+ leaf = leaf->next;
+ goto remove_node;
+ }
+ }
+
+ return;
+remove_node:
+ if (leaf->prev)
+ leaf->prev->next = leaf->next;
+ if (leaf->next)
+ leaf->next->prev = leaf->prev;
+ fuse_iext_remove_node(ifp, offset, leaf);
+}
+
+static void
+fuse_iext_free_last_leaf(
+ struct fuse_ifork *ifp)
+{
+ ifp->if_height--;
+ kfree(ifp->if_data);
+ ifp->if_data = NULL;
+}
+
+void
+fuse_iext_remove(
+ struct fuse_iomap_cache *ip,
+ struct fuse_iext_cursor *cur,
+ int state)
+{
+ struct fuse_ifork *ifp = fuse_iext_state_to_fork(ip, state);
+ struct fuse_iext_leaf *leaf = cur->leaf;
+ loff_t offset = fuse_iext_leaf_key(leaf, 0);
+ int i, nr_entries;
+
+ ASSERT(ifp->if_height > 0);
+ ASSERT(ifp->if_data != NULL);
+ ASSERT(fuse_iext_valid(ifp, cur));
+
+ fuse_iext_inc_seq(ip);
+
+ nr_entries = fuse_iext_leaf_nr_entries(ifp, leaf, cur->pos) - 1;
+ for (i = cur->pos; i < nr_entries; i++)
+ leaf->recs[i] = leaf->recs[i + 1];
+ fuse_iext_rec_clear(&leaf->recs[nr_entries]);
+ ifp->if_bytes -= sizeof(struct fuse_iomap_io);
+
+ if (cur->pos == 0 && nr_entries > 0) {
+ fuse_iext_update_node(ifp, offset, fuse_iext_leaf_key(leaf, 0), 1,
+ leaf);
+ offset = fuse_iext_leaf_key(leaf, 0);
+ } else if (cur->pos == nr_entries) {
+ if (ifp->if_height > 1 && leaf->next)
+ cur->leaf = leaf->next;
+ else
+ cur->leaf = NULL;
+ cur->pos = 0;
+ }
+
+ if (nr_entries >= RECS_PER_LEAF / 2)
+ return;
+
+ if (ifp->if_height > 1)
+ fuse_iext_rebalance_leaf(ifp, cur, leaf, offset, nr_entries);
+ else if (nr_entries == 0)
+ fuse_iext_free_last_leaf(ifp);
+}
+
+/*
+ * Lookup the extent covering offset.
+ *
+ * If there is an extent covering offset return the extent index, and store the
+ * expanded extent structure in *gotp, and the extent cursor in *cur.
+ * If there is no extent covering offset, but there is an extent after it (e.g.
+ * it lies in a hole) return that extent in *gotp and its cursor in *cur
+ * instead.
+ * If offset is beyond the last extent return false, and return an invalid
+ * cursor value.
+ */
+bool
+fuse_iext_lookup_extent(
+ struct fuse_iomap_cache *ip,
+ struct fuse_ifork *ifp,
+ loff_t offset,
+ struct fuse_iext_cursor *cur,
+ struct fuse_iomap_io *gotp)
+{
+ cur->leaf = fuse_iext_find_level(ifp, offset, 1);
+ if (!cur->leaf) {
+ cur->pos = 0;
+ return false;
+ }
+
+ for (cur->pos = 0; cur->pos < fuse_iext_max_recs(ifp); cur->pos++) {
+ struct fuse_iomap_io *rec = cur_rec(cur);
+
+ if (fuse_iext_rec_is_empty(rec))
+ break;
+ if (fuse_iext_rec_cmp(rec, offset) >= 0)
+ goto found;
+ }
+
+ /* Try looking in the next node for an entry > offset */
+ if (ifp->if_height == 1 || !cur->leaf->next)
+ return false;
+ cur->leaf = cur->leaf->next;
+ cur->pos = 0;
+ if (!fuse_iext_valid(ifp, cur))
+ return false;
+found:
+ fuse_iext_get(gotp, cur_rec(cur));
+ return true;
+}
+
+/*
+ * Returns the last extent before end, and if this extent doesn't cover
+ * end, update end to the end of the extent.
+ */
+bool
+fuse_iext_lookup_extent_before(
+ struct fuse_iomap_cache *ip,
+ struct fuse_ifork *ifp,
+ loff_t *end,
+ struct fuse_iext_cursor *cur,
+ struct fuse_iomap_io *gotp)
+{
+ /* could be optimized to not even look up the next on a match.. */
+ if (fuse_iext_lookup_extent(ip, ifp, *end - 1, cur, gotp) &&
+ gotp->offset <= *end - 1)
+ return true;
+ if (!fuse_iext_prev_extent(ifp, cur, gotp))
+ return false;
+ *end = gotp->offset + gotp->length;
+ return true;
+}
+
+void
+fuse_iext_update_extent(
+ struct fuse_iomap_cache *ip,
+ int state,
+ struct fuse_iext_cursor *cur,
+ struct fuse_iomap_io *new)
+{
+ struct fuse_ifork *ifp = fuse_iext_state_to_fork(ip, state);
+
+ fuse_iext_inc_seq(ip);
+
+ if (cur->pos == 0) {
+ struct fuse_iomap_io old;
+
+ fuse_iext_get(&old, cur_rec(cur));
+ if (new->offset != old.offset) {
+ fuse_iext_update_node(ifp, old.offset,
+ new->offset, 1, cur->leaf);
+ }
+ }
+
+ fuse_iext_set(cur_rec(cur), new);
+}
+
+/*
+ * Return true if the cursor points at an extent and return the extent structure
+ * in gotp. Else return false.
+ */
+bool
+fuse_iext_get_extent(
+ const struct fuse_ifork *ifp,
+ const struct fuse_iext_cursor *cur,
+ struct fuse_iomap_io *gotp)
+{
+ if (!fuse_iext_valid(ifp, cur))
+ return false;
+ fuse_iext_get(gotp, cur_rec(cur));
+ return true;
+}
+
+/*
+ * This is a recursive function, because of that we need to be extremely
+ * careful with stack usage.
+ */
+static void
+fuse_iext_destroy_node(
+ struct fuse_iext_node *node,
+ int level)
+{
+ int i;
+
+ if (level > 1) {
+ for (i = 0; i < KEYS_PER_NODE; i++) {
+ if (node->keys[i] == FUSE_IEXT_KEY_INVALID)
+ break;
+ fuse_iext_destroy_node(node->ptrs[i], level - 1);
+ }
+ }
+
+ kfree(node);
+}
+
+void
+fuse_iext_destroy(
+ struct fuse_ifork *ifp)
+{
+ fuse_iext_destroy_node(ifp->if_data, ifp->if_height);
+
+ ifp->if_bytes = 0;
+ ifp->if_height = 0;
+ ifp->if_data = NULL;
+}
+
+static inline struct fuse_ifork *
+fuse_iomap_fork_ptr(
+ struct fuse_iomap_cache *ip,
+ enum fuse_iomap_iodir iodir)
+{
+ switch (iodir) {
+ case READ_MAPPING:
+ return &ip->im_read;
+ case WRITE_MAPPING:
+ return ip->im_write;
+ default:
+ ASSERT(0);
+ return NULL;
+ }
+}
+
+static inline bool fuse_iomap_addrs_adjacent(const struct fuse_iomap_io *left,
+ const struct fuse_iomap_io *right)
+{
+ switch (left->type) {
+ case FUSE_IOMAP_TYPE_MAPPED:
+ case FUSE_IOMAP_TYPE_UNWRITTEN:
+ return left->addr + left->length == right->addr;
+ default:
+ return left->addr == FUSE_IOMAP_NULL_ADDR &&
+ right->addr == FUSE_IOMAP_NULL_ADDR;
+ }
+}
+
+static inline bool fuse_iomap_can_merge(const struct fuse_iomap_io *left,
+ const struct fuse_iomap_io *right)
+{
+ return (left->dev == right->dev &&
+ left->offset + left->length == right->offset &&
+ left->type == right->type &&
+ fuse_iomap_addrs_adjacent(left, right) &&
+ left->flags == right->flags &&
+ left->length + right->length <= FUSE_IOMAP_MAX_LEN);
+}
+
+static inline bool fuse_iomap_can_merge3(const struct fuse_iomap_io *left,
+ const struct fuse_iomap_io *new,
+ const struct fuse_iomap_io *right)
+{
+ return left->length + new->length + right->length <= FUSE_IOMAP_MAX_LEN;
+}
+
+#if IS_ENABLED(CONFIG_FUSE_IOMAP_DEBUG)
+static void fuse_iext_check_mappings(struct inode *inode,
+ struct fuse_iomap_cache *ip,
+ struct fuse_ifork *ifp)
+{
+ struct fuse_inode *fi = FUSE_I(ip);
+ struct fuse_iext_cursor icur;
+ struct fuse_iomap_io prev, got;
+ unsigned long long nr = 0;
+
+ if (!ifp || !static_branch_unlikely(&fuse_iomap_debug))
+ return;
+
+ fuse_iext_first(ifp, &icur);
+ if (!fuse_iext_get_extent(ifp, &icur, &prev))
+ return;
+ nr++;
+
+ fuse_iext_next(ifp, &icur);
+ while (fuse_iext_get_extent(ifp, &icur, &got)) {
+ if (got.length == 0 ||
+ got.offset < prev.offset + prev.length ||
+ fuse_iomap_can_merge(&prev, &got)) {
+ printk(KERN_ERR "FUSE IOMAP CORRUPTION ino=%llu nr=%llu",
+ fi->orig_ino, nr);
+ printk(KERN_ERR "prev: offset=%llu length=%llu type=%u flags=0x%x dev=%u addr=%llu\n",
+ prev.offset, prev.length, prev.type, prev.flags,
+ prev.dev, prev.addr);
+ printk(KERN_ERR "curr: offset=%llu length=%llu type=%u flags=0x%x dev=%u addr=%llu\n",
+ got.offset, got.length, got.type, got.flags,
+ got.dev, got.addr);
+ }
+
+ prev = got;
+ nr++;
+ fuse_iext_next(ifp, &icur);
+ }
+}
+#else
+# define fuse_iext_check_mappings(...) ((void)0)
+#endif
+
+static void
+fuse_iext_del_mapping(
+ struct fuse_iomap_cache *ip,
+ struct fuse_ifork *ifp,
+ struct fuse_iext_cursor *icur,
+ struct fuse_iomap_io *got, /* current extent entry */
+ struct fuse_iomap_io *del) /* data to remove from extents */
+{
+ struct fuse_iomap_io new; /* new record to be inserted */
+ /* first addr (fsblock aligned) past del */
+ uint64_t del_endaddr;
+ /* first offset (fsblock aligned) past del */
+ uint64_t del_endoff = del->offset + del->length;
+ /* first offset (fsblock aligned) past got */
+ uint64_t got_endoff = got->offset + got->length;
+ uint32_t state = fuse_iomap_fork_to_state(ip, ifp);
+
+ ASSERT(del->length > 0);
+ ASSERT(got->offset <= del->offset);
+ ASSERT(got_endoff >= del_endoff);
+
+ switch (del->type) {
+ case FUSE_IOMAP_TYPE_MAPPED:
+ case FUSE_IOMAP_TYPE_UNWRITTEN:
+ del_endaddr = del->addr + del->length;
+ break;
+ default:
+ del_endaddr = FUSE_IOMAP_NULL_ADDR;
+ break;
+ }
+
+ if (got->offset == del->offset)
+ state |= FUSE_IEXT_LEFT_FILLING;
+ if (got_endoff == del_endoff)
+ state |= FUSE_IEXT_RIGHT_FILLING;
+
+ switch (state & (FUSE_IEXT_LEFT_FILLING | FUSE_IEXT_RIGHT_FILLING)) {
+ case FUSE_IEXT_LEFT_FILLING | FUSE_IEXT_RIGHT_FILLING:
+ /*
+ * Matches the whole extent. Delete the entry.
+ */
+ fuse_iext_remove(ip, icur, state);
+ fuse_iext_prev(ifp, icur);
+ break;
+ case FUSE_IEXT_LEFT_FILLING:
+ /*
+ * Deleting the first part of the extent.
+ */
+ got->offset = del_endoff;
+ got->addr = del_endaddr;
+ got->length -= del->length;
+ fuse_iext_update_extent(ip, state, icur, got);
+ break;
+ case FUSE_IEXT_RIGHT_FILLING:
+ /*
+ * Deleting the last part of the extent.
+ */
+ got->length -= del->length;
+ fuse_iext_update_extent(ip, state, icur, got);
+ break;
+ case 0:
+ /*
+ * Deleting the middle of the extent.
+ */
+ got->length = del->offset - got->offset;
+ fuse_iext_update_extent(ip, state, icur, got);
+
+ new.offset = del_endoff;
+ new.length = got_endoff - del_endoff;
+ new.type = got->type;
+ new.flags = got->flags;
+ new.addr = del_endaddr;
+ new.dev = got->dev;
+
+ fuse_iext_next(ifp, icur);
+ fuse_iext_insert(ip, icur, &new, state);
+ break;
+ }
+}
+
+int
+fuse_iomap_cache_remove(
+ struct inode *inode,
+ enum fuse_iomap_iodir iodir,
+ loff_t start, /* first file offset deleted */
+ uint64_t len) /* length to unmap */
+{
+ struct fuse_iext_cursor icur;
+ struct fuse_iomap_io got; /* current extent record */
+ struct fuse_iomap_io del; /* extent being deleted */
+ loff_t end;
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_iomap_cache *ip = &fi->cache;
+ struct fuse_ifork *ifp = fuse_iomap_fork_ptr(ip, iodir);
+ bool wasreal;
+ bool done = false;
+ int ret = 0;
+
+ assert_cache_locked(ip);
+
+ if (!ifp || fuse_iext_count(ifp) == 0)
+ return 0;
+
+ /* Fast shortcut if the caller wants to erase everything */
+ if (start == 0 && len >= inode->i_sb->s_maxbytes) {
+ fuse_iext_destroy(ifp);
+ return 0;
+ }
+
+ if (!len)
+ goto out;
+
+ /*
+ * If the caller wants us to remove everything to EOF, we set the end
+ * of the removal range to the maximum file offset. We don't support
+ * unsigned file offsets.
+ */
+ if (len == FUSE_IOMAP_INVAL_TO_EOF) {
+ const unsigned int blocksize = i_blocksize(inode);
+
+ len = round_up(inode->i_sb->s_maxbytes, blocksize) - start;
+ }
+
+ /*
+ * Now that we've settled len, look up the extent before the end of the
+ * range.
+ */
+ end = start + len;
+ if (!fuse_iext_lookup_extent_before(ip, ifp, &end, &icur, &got))
+ goto out;
+ end--;
+
+ while (end != -1 && end >= start) {
+ /*
+ * Is the found extent after a hole in which end lives?
+ * Just back up to the previous extent, if so.
+ */
+ if (got.offset > end &&
+ !fuse_iext_prev_extent(ifp, &icur, &got)) {
+ done = true;
+ break;
+ }
+ /*
+ * Is the last block of this extent before the range
+ * we're supposed to delete? If so, we're done.
+ */
+ end = min_t(loff_t, end, got.offset + got.length - 1);
+ if (end < start)
+ break;
+ /*
+ * Then deal with the (possibly delayed) allocated space
+ * we found.
+ */
+ del = got;
+ switch (del.type) {
+ case FUSE_IOMAP_TYPE_DELALLOC:
+ case FUSE_IOMAP_TYPE_HOLE:
+ case FUSE_IOMAP_TYPE_INLINE:
+ case FUSE_IOMAP_TYPE_PURE_OVERWRITE:
+ wasreal = false;
+ break;
+ case FUSE_IOMAP_TYPE_MAPPED:
+ case FUSE_IOMAP_TYPE_UNWRITTEN:
+ wasreal = true;
+ break;
+ default:
+ ASSERT(0);
+ ret = -EFSCORRUPTED;
+ goto out;
+ }
+
+ if (got.offset < start) {
+ del.offset = start;
+ del.length -= start - got.offset;
+ if (wasreal)
+ del.addr += start - got.offset;
+ }
+ if (del.offset + del.length > end + 1)
+ del.length = end + 1 - del.offset;
+
+ fuse_iext_del_mapping(ip, ifp, &icur, &got, &del);
+ end = del.offset - 1;
+
+ /*
+ * If not done go on to the next (previous) record.
+ */
+ if (end != -1 && end >= start) {
+ if (!fuse_iext_get_extent(ifp, &icur, &got) ||
+ (got.offset > end &&
+ !fuse_iext_prev_extent(ifp, &icur, &got))) {
+ done = true;
+ break;
+ }
+ }
+ }
+
+ /* Should have removed everything */
+ if (len == 0 || done || end == (loff_t)-1 || end < start)
+ ret = 0;
+ else
+ ret = -EFSCORRUPTED;
+
+out:
+ fuse_iext_check_mappings(inode, ip, ifp);
+ return ret;
+}
+
+static void
+fuse_iext_add_mapping(
+ struct fuse_iomap_cache *ip,
+ struct fuse_ifork *ifp,
+ struct fuse_iext_cursor *icur,
+ const struct fuse_iomap_io *new) /* new extent entry */
+{
+ struct fuse_iomap_io left; /* left neighbor extent entry */
+ struct fuse_iomap_io right; /* right neighbor extent entry */
+ uint32_t state = fuse_iomap_fork_to_state(ip, ifp);
+
+ /*
+ * Check and set flags if this segment has a left neighbor.
+ */
+ if (fuse_iext_peek_prev_extent(ifp, icur, &left))
+ state |= FUSE_IEXT_LEFT_VALID;
+
+ /*
+ * Check and set flags if this segment has a current value.
+ * Not true if we're inserting into the "hole" at eof.
+ */
+ if (fuse_iext_get_extent(ifp, icur, &right))
+ state |= FUSE_IEXT_RIGHT_VALID;
+
+ /*
+ * We're inserting a real allocation between "left" and "right".
+ * Set the contiguity flags. Don't let extents get too large.
+ */
+ if ((state & FUSE_IEXT_LEFT_VALID) && fuse_iomap_can_merge(&left, new))
+ state |= FUSE_IEXT_LEFT_CONTIG;
+
+ if ((state & FUSE_IEXT_RIGHT_VALID) &&
+ fuse_iomap_can_merge(new, &right) &&
+ (!(state & FUSE_IEXT_LEFT_CONTIG) ||
+ fuse_iomap_can_merge3(&left, new, &right)))
+ state |= FUSE_IEXT_RIGHT_CONTIG;
+
+ /*
+ * Select which case we're in here, and implement it.
+ */
+ switch (state & (FUSE_IEXT_LEFT_CONTIG | FUSE_IEXT_RIGHT_CONTIG)) {
+ case FUSE_IEXT_LEFT_CONTIG | FUSE_IEXT_RIGHT_CONTIG:
+ /*
+ * New allocation is contiguous with real allocations on the
+ * left and on the right.
+ * Merge all three into a single extent record.
+ */
+ left.length += new->length + right.length;
+
+ fuse_iext_remove(ip, icur, state);
+ fuse_iext_prev(ifp, icur);
+ fuse_iext_update_extent(ip, state, icur, &left);
+ break;
+
+ case FUSE_IEXT_LEFT_CONTIG:
+ /*
+ * New allocation is contiguous with a real allocation
+ * on the left.
+ * Merge the new allocation with the left neighbor.
+ */
+ left.length += new->length;
+
+ fuse_iext_prev(ifp, icur);
+ fuse_iext_update_extent(ip, state, icur, &left);
+ break;
+
+ case FUSE_IEXT_RIGHT_CONTIG:
+ /*
+ * New allocation is contiguous with a real allocation
+ * on the right.
+ * Merge the new allocation with the right neighbor.
+ */
+ right.offset = new->offset;
+ right.addr = new->addr;
+ right.length += new->length;
+ fuse_iext_update_extent(ip, state, icur, &right);
+ break;
+
+ case 0:
+ /*
+ * New allocation is not contiguous with another
+ * real allocation.
+ * Insert a new entry.
+ */
+ fuse_iext_insert(ip, icur, new, state);
+ break;
+ }
+}
+
+static int
+fuse_iomap_cache_add(
+ struct inode *inode,
+ enum fuse_iomap_iodir iodir,
+ const struct fuse_iomap_io *new)
+{
+ struct fuse_iext_cursor icur;
+ struct fuse_iomap_io got;
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_iomap_cache *ip = &fi->cache;
+ struct fuse_ifork *ifp = fuse_iomap_fork_ptr(ip, iodir);
+
+ assert_cache_locked(ip);
+ ASSERT(new->length > 0);
+ ASSERT(new->offset < inode->i_sb->s_maxbytes);
+
+ if (!ifp) {
+ ifp = kzalloc(sizeof(struct fuse_ifork),
+ GFP_KERNEL | __GFP_NOFAIL);
+ if (!ifp)
+ return -ENOMEM;
+
+ ip->im_write = ifp;
+ }
+
+ if (fuse_iext_lookup_extent(ip, ifp, new->offset, &icur, &got)) {
+ /* make sure we only add into a hole. */
+ ASSERT(got.offset > new->offset);
+ ASSERT(got.offset - new->offset >= new->length);
+
+ if (got.offset <= new->offset ||
+ got.offset - new->offset < new->length)
+ return -EFSCORRUPTED;
+ }
+
+ fuse_iext_add_mapping(ip, ifp, &icur, new);
+ fuse_iext_check_mappings(inode, ip, ifp);
+ return 0;
+}
+
+int
+fuse_iomap_cache_upsert(
+ struct inode *inode,
+ enum fuse_iomap_iodir iodir,
+ const struct fuse_iomap_io *map)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_iomap_cache *ip = &fi->cache;
+ int err;
+
+ /*
+ * We interpret no write fork to mean that all writes are pure
+ * overwrites. Avoid wasting memory if we're trying to upsert a
+ * pure overwrite.
+ */
+ if (iodir == WRITE_MAPPING &&
+ map->type == FUSE_IOMAP_TYPE_PURE_OVERWRITE &&
+ ip->im_write == NULL)
+ return 0;
+
+ err = fuse_iomap_cache_remove(inode, iodir, map->offset, map->length);
+ if (err)
+ return err;
+
+ return fuse_iomap_cache_add(inode, iodir, map);
+}
+
+/*
+ * Trim the returned map to the required bounds
+ */
+static void
+fuse_iomap_trim(
+ struct fuse_inode *fi,
+ struct fuse_iomap_lookup *mval,
+ const struct fuse_iomap_io *got,
+ loff_t off,
+ loff_t len)
+{
+ struct fuse_iomap_cache *ip = &fi->cache;
+ const unsigned int blocksize = i_blocksize(&fi->inode);
+ const loff_t aligned_off = round_down(off, blocksize);
+ const loff_t aligned_end = round_up(off + len, blocksize);
+ const loff_t aligned_len = aligned_end - aligned_off;
+
+ ASSERT(aligned_off >= got->offset);
+
+ switch (got->type) {
+ case FUSE_IOMAP_TYPE_MAPPED:
+ case FUSE_IOMAP_TYPE_UNWRITTEN:
+ mval->map.addr = got->addr + (aligned_off - got->offset);
+ break;
+ default:
+ mval->map.addr = FUSE_IOMAP_NULL_ADDR;
+ break;
+ }
+ mval->map.offset = aligned_off;
+ mval->map.length = min_t(loff_t, aligned_len,
+ got->length - (aligned_off - got->offset));
+ mval->map.type = got->type;
+ mval->map.flags = got->flags;
+ mval->map.dev = got->dev;
+ mval->validity_cookie = fuse_iext_read_seq(ip);
+}
+
+enum fuse_iomap_lookup_result
+fuse_iomap_cache_lookup(
+ struct inode *inode,
+ enum fuse_iomap_iodir iodir,
+ loff_t off,
+ uint64_t len,
+ struct fuse_iomap_lookup *mval)
+{
+ struct fuse_iomap_io got;
+ struct fuse_iext_cursor icur;
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_iomap_cache *ip = &fi->cache;
+ struct fuse_ifork *ifp = fuse_iomap_fork_ptr(ip, iodir);
+
+ assert_cache_locked_shared(ip);
+
+ if (!ifp) {
+ /*
+ * No write fork at all means this filesystem doesn't do out of
+ * place writes.
+ */
+ return LOOKUP_NOFORK;
+ }
+
+ if (!fuse_iext_lookup_extent(ip, ifp, off, &icur, &got)) {
+ /*
+ * Write fork does not contain a mapping at or beyond off,
+ * which is a cache miss.
+ */
+ return LOOKUP_MISS;
+ }
+
+ if (got.offset > off) {
+ /*
+ * Found a mapping, but it doesn't cover the start of the
+ * range, which is effectively a miss.
+ */
+ return LOOKUP_MISS;
+ }
+
+ /* Found a mapping in the cache, return it */
+ fuse_iomap_trim(fi, mval, &got, off, len);
+ return LOOKUP_HIT;
+}
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