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-rw-r--r--fs/libfs.c96
-rw-r--r--include/linux/fs.h6
-rw-r--r--include/linux/maple_tree.h7
-rw-r--r--lib/maple_tree.c93
-rw-r--r--lib/test_maple_tree.c44
-rw-r--r--mm/shmem.c4
6 files changed, 215 insertions, 35 deletions
diff --git a/fs/libfs.c b/fs/libfs.c
index 6fb8244b259e..6182e2b03094 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -240,17 +240,22 @@ const struct inode_operations simple_dir_inode_operations = {
};
EXPORT_SYMBOL(simple_dir_inode_operations);
-static void offset_set(struct dentry *dentry, u32 offset)
+/* 0 is '.', 1 is '..', so always start with offset 2 or more */
+enum {
+ DIR_OFFSET_MIN = 2,
+};
+
+static void offset_set(struct dentry *dentry, long offset)
{
- dentry->d_fsdata = (void *)((uintptr_t)(offset));
+ dentry->d_fsdata = (void *)offset;
}
-static u32 dentry2offset(struct dentry *dentry)
+static long dentry2offset(struct dentry *dentry)
{
- return (u32)((uintptr_t)(dentry->d_fsdata));
+ return (long)dentry->d_fsdata;
}
-static struct lock_class_key simple_offset_xa_lock;
+static struct lock_class_key simple_offset_lock_class;
/**
* simple_offset_init - initialize an offset_ctx
@@ -259,11 +264,9 @@ static struct lock_class_key simple_offset_xa_lock;
*/
void simple_offset_init(struct offset_ctx *octx)
{
- xa_init_flags(&octx->xa, XA_FLAGS_ALLOC1);
- lockdep_set_class(&octx->xa.xa_lock, &simple_offset_xa_lock);
-
- /* 0 is '.', 1 is '..', so always start with offset 2 */
- octx->next_offset = 2;
+ mt_init_flags(&octx->mt, MT_FLAGS_ALLOC_RANGE);
+ lockdep_set_class(&octx->mt.ma_lock, &simple_offset_lock_class);
+ octx->next_offset = DIR_OFFSET_MIN;
}
/**
@@ -271,20 +274,19 @@ void simple_offset_init(struct offset_ctx *octx)
* @octx: directory offset ctx to be updated
* @dentry: new dentry being added
*
- * Returns zero on success. @so_ctx and the dentry offset are updated.
+ * Returns zero on success. @octx and the dentry's offset are updated.
* Otherwise, a negative errno value is returned.
*/
int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry)
{
- static const struct xa_limit limit = XA_LIMIT(2, U32_MAX);
- u32 offset;
+ unsigned long offset;
int ret;
if (dentry2offset(dentry) != 0)
return -EBUSY;
- ret = xa_alloc_cyclic(&octx->xa, &offset, dentry, limit,
- &octx->next_offset, GFP_KERNEL);
+ ret = mtree_alloc_cyclic(&octx->mt, &offset, dentry, DIR_OFFSET_MIN,
+ LONG_MAX, &octx->next_offset, GFP_KERNEL);
if (ret < 0)
return ret;
@@ -300,17 +302,49 @@ int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry)
*/
void simple_offset_remove(struct offset_ctx *octx, struct dentry *dentry)
{
- u32 offset;
+ long offset;
offset = dentry2offset(dentry);
if (offset == 0)
return;
- xa_erase(&octx->xa, offset);
+ mtree_erase(&octx->mt, offset);
offset_set(dentry, 0);
}
/**
+ * simple_offset_empty - Check if a dentry can be unlinked
+ * @dentry: dentry to be tested
+ *
+ * Returns 0 if @dentry is a non-empty directory; otherwise returns 1.
+ */
+int simple_offset_empty(struct dentry *dentry)
+{
+ struct inode *inode = d_inode(dentry);
+ struct offset_ctx *octx;
+ struct dentry *child;
+ unsigned long index;
+ int ret = 1;
+
+ if (!inode || !S_ISDIR(inode->i_mode))
+ return ret;
+
+ index = DIR_OFFSET_MIN;
+ octx = inode->i_op->get_offset_ctx(inode);
+ mt_for_each(&octx->mt, child, index, LONG_MAX) {
+ spin_lock(&child->d_lock);
+ if (simple_positive(child)) {
+ spin_unlock(&child->d_lock);
+ ret = 0;
+ break;
+ }
+ spin_unlock(&child->d_lock);
+ }
+
+ return ret;
+}
+
+/**
* simple_offset_rename_exchange - exchange rename with directory offsets
* @old_dir: parent of dentry being moved
* @old_dentry: dentry being moved
@@ -327,8 +361,8 @@ int simple_offset_rename_exchange(struct inode *old_dir,
{
struct offset_ctx *old_ctx = old_dir->i_op->get_offset_ctx(old_dir);
struct offset_ctx *new_ctx = new_dir->i_op->get_offset_ctx(new_dir);
- u32 old_index = dentry2offset(old_dentry);
- u32 new_index = dentry2offset(new_dentry);
+ long old_index = dentry2offset(old_dentry);
+ long new_index = dentry2offset(new_dentry);
int ret;
simple_offset_remove(old_ctx, old_dentry);
@@ -354,9 +388,9 @@ int simple_offset_rename_exchange(struct inode *old_dir,
out_restore:
offset_set(old_dentry, old_index);
- xa_store(&old_ctx->xa, old_index, old_dentry, GFP_KERNEL);
+ mtree_store(&old_ctx->mt, old_index, old_dentry, GFP_KERNEL);
offset_set(new_dentry, new_index);
- xa_store(&new_ctx->xa, new_index, new_dentry, GFP_KERNEL);
+ mtree_store(&new_ctx->mt, new_index, new_dentry, GFP_KERNEL);
return ret;
}
@@ -369,7 +403,7 @@ out_restore:
*/
void simple_offset_destroy(struct offset_ctx *octx)
{
- xa_destroy(&octx->xa);
+ mtree_destroy(&octx->mt);
}
/**
@@ -399,15 +433,16 @@ static loff_t offset_dir_llseek(struct file *file, loff_t offset, int whence)
/* In this case, ->private_data is protected by f_pos_lock */
file->private_data = NULL;
- return vfs_setpos(file, offset, U32_MAX);
+ return vfs_setpos(file, offset, LONG_MAX);
}
-static struct dentry *offset_find_next(struct xa_state *xas)
+static struct dentry *offset_find_next(struct offset_ctx *octx, loff_t offset)
{
+ MA_STATE(mas, &octx->mt, offset, offset);
struct dentry *child, *found = NULL;
rcu_read_lock();
- child = xas_next_entry(xas, U32_MAX);
+ child = mas_find(&mas, LONG_MAX);
if (!child)
goto out;
spin_lock(&child->d_lock);
@@ -421,8 +456,8 @@ out:
static bool offset_dir_emit(struct dir_context *ctx, struct dentry *dentry)
{
- u32 offset = dentry2offset(dentry);
struct inode *inode = d_inode(dentry);
+ long offset = dentry2offset(dentry);
return ctx->actor(ctx, dentry->d_name.name, dentry->d_name.len, offset,
inode->i_ino, fs_umode_to_dtype(inode->i_mode));
@@ -430,12 +465,11 @@ static bool offset_dir_emit(struct dir_context *ctx, struct dentry *dentry)
static void *offset_iterate_dir(struct inode *inode, struct dir_context *ctx)
{
- struct offset_ctx *so_ctx = inode->i_op->get_offset_ctx(inode);
- XA_STATE(xas, &so_ctx->xa, ctx->pos);
+ struct offset_ctx *octx = inode->i_op->get_offset_ctx(inode);
struct dentry *dentry;
while (true) {
- dentry = offset_find_next(&xas);
+ dentry = offset_find_next(octx, ctx->pos);
if (!dentry)
return ERR_PTR(-ENOENT);
@@ -444,8 +478,8 @@ static void *offset_iterate_dir(struct inode *inode, struct dir_context *ctx)
break;
}
+ ctx->pos = dentry2offset(dentry) + 1;
dput(dentry);
- ctx->pos = xas.xa_index + 1;
}
return NULL;
}
@@ -481,7 +515,7 @@ static int offset_readdir(struct file *file, struct dir_context *ctx)
return 0;
/* In this case, ->private_data is protected by f_pos_lock */
- if (ctx->pos == 2)
+ if (ctx->pos == DIR_OFFSET_MIN)
file->private_data = NULL;
else if (file->private_data == ERR_PTR(-ENOENT))
return 0;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 2e07cbbf92e3..d15d808e8e31 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -43,6 +43,7 @@
#include <linux/cred.h>
#include <linux/mnt_idmapping.h>
#include <linux/slab.h>
+#include <linux/maple_tree.h>
#include <asm/byteorder.h>
#include <uapi/linux/fs.h>
@@ -3288,13 +3289,14 @@ extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
const void __user *from, size_t count);
struct offset_ctx {
- struct xarray xa;
- u32 next_offset;
+ struct maple_tree mt;
+ unsigned long next_offset;
};
void simple_offset_init(struct offset_ctx *octx);
int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry);
void simple_offset_remove(struct offset_ctx *octx, struct dentry *dentry);
+int simple_offset_empty(struct dentry *dentry);
int simple_offset_rename_exchange(struct inode *old_dir,
struct dentry *old_dentry,
struct inode *new_dir,
diff --git a/include/linux/maple_tree.h b/include/linux/maple_tree.h
index b3d63123b945..a53ad4dabd7e 100644
--- a/include/linux/maple_tree.h
+++ b/include/linux/maple_tree.h
@@ -171,6 +171,7 @@ enum maple_type {
#define MT_FLAGS_LOCK_IRQ 0x100
#define MT_FLAGS_LOCK_BH 0x200
#define MT_FLAGS_LOCK_EXTERN 0x300
+#define MT_FLAGS_ALLOC_WRAPPED 0x0800
#define MAPLE_HEIGHT_MAX 31
@@ -319,6 +320,9 @@ int mtree_insert_range(struct maple_tree *mt, unsigned long first,
int mtree_alloc_range(struct maple_tree *mt, unsigned long *startp,
void *entry, unsigned long size, unsigned long min,
unsigned long max, gfp_t gfp);
+int mtree_alloc_cyclic(struct maple_tree *mt, unsigned long *startp,
+ void *entry, unsigned long range_lo, unsigned long range_hi,
+ unsigned long *next, gfp_t gfp);
int mtree_alloc_rrange(struct maple_tree *mt, unsigned long *startp,
void *entry, unsigned long size, unsigned long min,
unsigned long max, gfp_t gfp);
@@ -499,6 +503,9 @@ void *mas_find_range(struct ma_state *mas, unsigned long max);
void *mas_find_rev(struct ma_state *mas, unsigned long min);
void *mas_find_range_rev(struct ma_state *mas, unsigned long max);
int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp);
+int mas_alloc_cyclic(struct ma_state *mas, unsigned long *startp,
+ void *entry, unsigned long range_lo, unsigned long range_hi,
+ unsigned long *next, gfp_t gfp);
bool mas_nomem(struct ma_state *mas, gfp_t gfp);
void mas_pause(struct ma_state *mas);
diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 6f241bb38799..af0970288727 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4290,6 +4290,56 @@ exists:
}
+/**
+ * mas_alloc_cyclic() - Internal call to find somewhere to store an entry
+ * @mas: The maple state.
+ * @startp: Pointer to ID.
+ * @range_lo: Lower bound of range to search.
+ * @range_hi: Upper bound of range to search.
+ * @entry: The entry to store.
+ * @next: Pointer to next ID to allocate.
+ * @gfp: The GFP_FLAGS to use for allocations.
+ *
+ * Return: 0 if the allocation succeeded without wrapping, 1 if the
+ * allocation succeeded after wrapping, or -EBUSY if there are no
+ * free entries.
+ */
+int mas_alloc_cyclic(struct ma_state *mas, unsigned long *startp,
+ void *entry, unsigned long range_lo, unsigned long range_hi,
+ unsigned long *next, gfp_t gfp)
+{
+ unsigned long min = range_lo;
+ int ret = 0;
+
+ range_lo = max(min, *next);
+ ret = mas_empty_area(mas, range_lo, range_hi, 1);
+ if ((mas->tree->ma_flags & MT_FLAGS_ALLOC_WRAPPED) && ret == 0) {
+ mas->tree->ma_flags &= ~MT_FLAGS_ALLOC_WRAPPED;
+ ret = 1;
+ }
+ if (ret < 0 && range_lo > min) {
+ ret = mas_empty_area(mas, min, range_hi, 1);
+ if (ret == 0)
+ ret = 1;
+ }
+ if (ret < 0)
+ return ret;
+
+ do {
+ mas_insert(mas, entry);
+ } while (mas_nomem(mas, gfp));
+ if (mas_is_err(mas))
+ return xa_err(mas->node);
+
+ *startp = mas->index;
+ *next = *startp + 1;
+ if (*next == 0)
+ mas->tree->ma_flags |= MT_FLAGS_ALLOC_WRAPPED;
+
+ return ret;
+}
+EXPORT_SYMBOL(mas_alloc_cyclic);
+
static __always_inline void mas_rewalk(struct ma_state *mas, unsigned long index)
{
retry:
@@ -6443,6 +6493,49 @@ unlock:
}
EXPORT_SYMBOL(mtree_alloc_range);
+/**
+ * mtree_alloc_cyclic() - Find somewhere to store this entry in the tree.
+ * @mt: The maple tree.
+ * @startp: Pointer to ID.
+ * @range_lo: Lower bound of range to search.
+ * @range_hi: Upper bound of range to search.
+ * @entry: The entry to store.
+ * @next: Pointer to next ID to allocate.
+ * @gfp: The GFP_FLAGS to use for allocations.
+ *
+ * Finds an empty entry in @mt after @next, stores the new index into
+ * the @id pointer, stores the entry at that index, then updates @next.
+ *
+ * @mt must be initialized with the MT_FLAGS_ALLOC_RANGE flag.
+ *
+ * Context: Any context. Takes and releases the mt.lock. May sleep if
+ * the @gfp flags permit.
+ *
+ * Return: 0 if the allocation succeeded without wrapping, 1 if the
+ * allocation succeeded after wrapping, -ENOMEM if memory could not be
+ * allocated, -EINVAL if @mt cannot be used, or -EBUSY if there are no
+ * free entries.
+ */
+int mtree_alloc_cyclic(struct maple_tree *mt, unsigned long *startp,
+ void *entry, unsigned long range_lo, unsigned long range_hi,
+ unsigned long *next, gfp_t gfp)
+{
+ int ret;
+
+ MA_STATE(mas, mt, 0, 0);
+
+ if (!mt_is_alloc(mt))
+ return -EINVAL;
+ if (WARN_ON_ONCE(mt_is_reserved(entry)))
+ return -EINVAL;
+ mtree_lock(mt);
+ ret = mas_alloc_cyclic(&mas, startp, entry, range_lo, range_hi,
+ next, gfp);
+ mtree_unlock(mt);
+ return ret;
+}
+EXPORT_SYMBOL(mtree_alloc_cyclic);
+
int mtree_alloc_rrange(struct maple_tree *mt, unsigned long *startp,
void *entry, unsigned long size, unsigned long min,
unsigned long max, gfp_t gfp)
diff --git a/lib/test_maple_tree.c b/lib/test_maple_tree.c
index 29185ac5c727..399380db449c 100644
--- a/lib/test_maple_tree.c
+++ b/lib/test_maple_tree.c
@@ -3599,6 +3599,45 @@ static noinline void __init check_state_handling(struct maple_tree *mt)
mas_unlock(&mas);
}
+static noinline void __init alloc_cyclic_testing(struct maple_tree *mt)
+{
+ unsigned long location;
+ unsigned long next;
+ int ret = 0;
+ MA_STATE(mas, mt, 0, 0);
+
+ next = 0;
+ mtree_lock(mt);
+ for (int i = 0; i < 100; i++) {
+ mas_alloc_cyclic(&mas, &location, mt, 2, ULONG_MAX, &next, GFP_KERNEL);
+ MAS_BUG_ON(&mas, i != location - 2);
+ MAS_BUG_ON(&mas, mas.index != location);
+ MAS_BUG_ON(&mas, mas.last != location);
+ MAS_BUG_ON(&mas, i != next - 3);
+ }
+
+ mtree_unlock(mt);
+ mtree_destroy(mt);
+ next = 0;
+ mt_init_flags(mt, MT_FLAGS_ALLOC_RANGE);
+ for (int i = 0; i < 100; i++) {
+ mtree_alloc_cyclic(mt, &location, mt, 2, ULONG_MAX, &next, GFP_KERNEL);
+ MT_BUG_ON(mt, i != location - 2);
+ MT_BUG_ON(mt, i != next - 3);
+ MT_BUG_ON(mt, mtree_load(mt, location) != mt);
+ }
+
+ mtree_destroy(mt);
+ /* Overflow test */
+ next = ULONG_MAX - 1;
+ ret = mtree_alloc_cyclic(mt, &location, mt, 2, ULONG_MAX, &next, GFP_KERNEL);
+ MT_BUG_ON(mt, ret != 0);
+ ret = mtree_alloc_cyclic(mt, &location, mt, 2, ULONG_MAX, &next, GFP_KERNEL);
+ MT_BUG_ON(mt, ret != 0);
+ ret = mtree_alloc_cyclic(mt, &location, mt, 2, ULONG_MAX, &next, GFP_KERNEL);
+ MT_BUG_ON(mt, ret != 1);
+}
+
static DEFINE_MTREE(tree);
static int __init maple_tree_seed(void)
{
@@ -3880,6 +3919,11 @@ static int __init maple_tree_seed(void)
check_state_handling(&tree);
mtree_destroy(&tree);
+ mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE);
+ alloc_cyclic_testing(&tree);
+ mtree_destroy(&tree);
+
+
#if defined(BENCH)
skip:
#endif
diff --git a/mm/shmem.c b/mm/shmem.c
index d7c84ff62186..6fed524343cb 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -3374,7 +3374,7 @@ static int shmem_unlink(struct inode *dir, struct dentry *dentry)
static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
{
- if (!simple_empty(dentry))
+ if (!simple_offset_empty(dentry))
return -ENOTEMPTY;
drop_nlink(d_inode(dentry));
@@ -3431,7 +3431,7 @@ static int shmem_rename2(struct mnt_idmap *idmap,
return simple_offset_rename_exchange(old_dir, old_dentry,
new_dir, new_dentry);
- if (!simple_empty(new_dentry))
+ if (!simple_offset_empty(new_dentry))
return -ENOTEMPTY;
if (flags & RENAME_WHITEOUT) {
generated by cgit v1.2.3 (git 2.39.0) at 2024-08-20 15:53:31 +0300