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Diffstat (limited to 'fs/btrfs/extent_io.c')
-rw-r--r--fs/btrfs/extent_io.c387
1 files changed, 252 insertions, 135 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 8b4bef05e222..7441245b1ceb 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -14,7 +14,6 @@
#include <linux/pagevec.h>
#include <linux/prefetch.h>
#include <linux/fsverity.h>
-#include "misc.h"
#include "extent_io.h"
#include "extent-io-tree.h"
#include "extent_map.h"
@@ -22,7 +21,6 @@
#include "btrfs_inode.h"
#include "bio.h"
#include "locking.h"
-#include "rcu-string.h"
#include "backref.h"
#include "disk-io.h"
#include "subpage.h"
@@ -78,10 +76,11 @@ void btrfs_extent_buffer_leak_debug_check(struct btrfs_fs_info *fs_info)
eb = list_first_entry(&fs_info->allocated_ebs,
struct extent_buffer, leak_list);
pr_err(
- "BTRFS: buffer leak start %llu len %lu refs %d bflags %lu owner %llu\n",
+ "BTRFS: buffer leak start %llu len %u refs %d bflags %lu owner %llu\n",
eb->start, eb->len, atomic_read(&eb->refs), eb->bflags,
btrfs_header_owner(eb));
list_del(&eb->leak_list);
+ WARN_ON_ONCE(1);
kmem_cache_free(extent_buffer_cache, eb);
}
spin_unlock_irqrestore(&fs_info->eb_leak_lock, flags);
@@ -147,8 +146,8 @@ static void submit_write_bio(struct btrfs_bio_ctrl *bio_ctrl, int ret)
int __init extent_buffer_init_cachep(void)
{
extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
- sizeof(struct extent_buffer), 0,
- SLAB_MEM_SPREAD, NULL);
+ sizeof(struct extent_buffer), 0, 0,
+ NULL);
if (!extent_buffer_cache)
return -ENOMEM;
@@ -207,7 +206,7 @@ static void __process_pages_contig(struct address_space *mapping,
struct page *locked_page, u64 start, u64 end,
unsigned long page_ops)
{
- struct btrfs_fs_info *fs_info = btrfs_sb(mapping->host->i_sb);
+ struct btrfs_fs_info *fs_info = inode_to_fs_info(mapping->host);
pgoff_t start_index = start >> PAGE_SHIFT;
pgoff_t end_index = end >> PAGE_SHIFT;
pgoff_t index = start_index;
@@ -251,7 +250,7 @@ static noinline int lock_delalloc_pages(struct inode *inode,
u64 start,
u64 end)
{
- struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
struct address_space *mapping = inode->i_mapping;
pgoff_t start_index = start >> PAGE_SHIFT;
pgoff_t end_index = end >> PAGE_SHIFT;
@@ -323,7 +322,7 @@ noinline_for_stack bool find_lock_delalloc_range(struct inode *inode,
struct page *locked_page, u64 *start,
u64 *end)
{
- struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
const u64 orig_start = *start;
const u64 orig_end = *end;
@@ -433,7 +432,7 @@ static bool btrfs_verify_page(struct page *page, u64 start)
static void end_page_read(struct page *page, bool uptodate, u64 start, u32 len)
{
- struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
+ struct btrfs_fs_info *fs_info = page_to_fs_info(page);
struct folio *folio = page_folio(page);
ASSERT(page_offset(page) <= start &&
@@ -462,16 +461,15 @@ static void end_page_read(struct page *page, bool uptodate, u64 start, u32 len)
*/
static void end_bbio_data_write(struct btrfs_bio *bbio)
{
+ struct btrfs_fs_info *fs_info = bbio->fs_info;
struct bio *bio = &bbio->bio;
int error = blk_status_to_errno(bio->bi_status);
struct folio_iter fi;
+ const u32 sectorsize = fs_info->sectorsize;
ASSERT(!bio_flagged(bio, BIO_CLONED));
bio_for_each_folio_all(fi, bio) {
struct folio *folio = fi.folio;
- struct inode *inode = folio->mapping->host;
- struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
- const u32 sectorsize = fs_info->sectorsize;
u64 start = folio_pos(folio) + fi.offset;
u32 len = fi.length;
@@ -593,22 +591,17 @@ static void begin_page_read(struct btrfs_fs_info *fs_info, struct page *page)
*/
static void end_bbio_data_read(struct btrfs_bio *bbio)
{
+ struct btrfs_fs_info *fs_info = bbio->fs_info;
struct bio *bio = &bbio->bio;
struct processed_extent processed = { 0 };
struct folio_iter fi;
- /*
- * The offset to the beginning of a bio, since one bio can never be
- * larger than UINT_MAX, u32 here is enough.
- */
- u32 bio_offset = 0;
+ const u32 sectorsize = fs_info->sectorsize;
ASSERT(!bio_flagged(bio, BIO_CLONED));
bio_for_each_folio_all(fi, &bbio->bio) {
bool uptodate = !bio->bi_status;
struct folio *folio = fi.folio;
struct inode *inode = folio->mapping->host;
- struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
- const u32 sectorsize = fs_info->sectorsize;
u64 start;
u64 end;
u32 len;
@@ -667,10 +660,6 @@ static void end_bbio_data_read(struct btrfs_bio *bbio)
end_page_read(folio_page(folio, 0), uptodate, start, len);
endio_readpage_release_extent(&processed, BTRFS_I(inode),
start, end, uptodate);
-
- ASSERT(bio_offset + len > bio_offset);
- bio_offset += len;
-
}
/* Release the last extent */
endio_readpage_release_extent(&processed, NULL, 0, 0, false);
@@ -738,6 +727,8 @@ static int alloc_eb_folio_array(struct extent_buffer *eb, gfp_t extra_gfp)
for (int i = 0; i < num_pages; i++)
eb->folios[i] = page_folio(page_array[i]);
+ eb->folio_size = PAGE_SIZE;
+ eb->folio_shift = PAGE_SHIFT;
return 0;
}
@@ -827,7 +818,7 @@ static void submit_extent_page(struct btrfs_bio_ctrl *bio_ctrl,
u64 disk_bytenr, struct page *page,
size_t size, unsigned long pg_offset)
{
- struct btrfs_inode *inode = BTRFS_I(page->mapping->host);
+ struct btrfs_inode *inode = page_to_inode(page);
ASSERT(pg_offset + size <= PAGE_SIZE);
ASSERT(bio_ctrl->end_io_func);
@@ -936,17 +927,21 @@ static int attach_extent_buffer_folio(struct extent_buffer *eb,
int set_page_extent_mapped(struct page *page)
{
- struct folio *folio = page_folio(page);
+ return set_folio_extent_mapped(page_folio(page));
+}
+
+int set_folio_extent_mapped(struct folio *folio)
+{
struct btrfs_fs_info *fs_info;
- ASSERT(page->mapping);
+ ASSERT(folio->mapping);
if (folio_test_private(folio))
return 0;
- fs_info = btrfs_sb(page->mapping->host->i_sb);
+ fs_info = folio_to_fs_info(folio);
- if (btrfs_is_subpage(fs_info, page->mapping))
+ if (btrfs_is_subpage(fs_info, folio->mapping))
return btrfs_attach_subpage(fs_info, folio, BTRFS_SUBPAGE_DATA);
folio_attach_private(folio, (void *)EXTENT_FOLIO_PRIVATE);
@@ -963,20 +958,21 @@ void clear_page_extent_mapped(struct page *page)
if (!folio_test_private(folio))
return;
- fs_info = btrfs_sb(page->mapping->host->i_sb);
+ fs_info = page_to_fs_info(page);
if (btrfs_is_subpage(fs_info, page->mapping))
return btrfs_detach_subpage(fs_info, folio);
folio_detach_private(folio);
}
-static struct extent_map *
-__get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
+static struct extent_map *__get_extent_map(struct inode *inode, struct page *page,
u64 start, u64 len, struct extent_map **em_cached)
{
struct extent_map *em;
- if (em_cached && *em_cached) {
+ ASSERT(em_cached);
+
+ if (*em_cached) {
em = *em_cached;
if (extent_map_in_tree(em) && start >= em->start &&
start < extent_map_end(em)) {
@@ -988,8 +984,8 @@ __get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
*em_cached = NULL;
}
- em = btrfs_get_extent(BTRFS_I(inode), page, pg_offset, start, len);
- if (em_cached && !IS_ERR(em)) {
+ em = btrfs_get_extent(BTRFS_I(inode), page, start, len);
+ if (!IS_ERR(em)) {
BUG_ON(*em_cached);
refcount_inc(&em->refs);
*em_cached = em;
@@ -1007,7 +1003,7 @@ static int btrfs_do_readpage(struct page *page, struct extent_map **em_cached,
struct btrfs_bio_ctrl *bio_ctrl, u64 *prev_em_start)
{
struct inode *inode = page->mapping->host;
- struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
u64 start = page_offset(page);
const u64 end = start + PAGE_SIZE - 1;
u64 cur = start;
@@ -1018,7 +1014,7 @@ static int btrfs_do_readpage(struct page *page, struct extent_map **em_cached,
int ret = 0;
size_t pg_offset = 0;
size_t iosize;
- size_t blocksize = inode->i_sb->s_blocksize;
+ size_t blocksize = fs_info->sectorsize;
struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
ret = set_page_extent_mapped(page);
@@ -1051,8 +1047,7 @@ static int btrfs_do_readpage(struct page *page, struct extent_map **em_cached,
end_page_read(page, true, cur, iosize);
break;
}
- em = __get_extent_map(inode, page, pg_offset, cur,
- end - cur + 1, em_cached);
+ em = __get_extent_map(inode, page, cur, end - cur + 1, em_cached);
if (IS_ERR(em)) {
unlock_extent(tree, cur, end, NULL);
end_page_read(page, false, cur, end + 1 - cur);
@@ -1157,15 +1152,18 @@ static int btrfs_do_readpage(struct page *page, struct extent_map **em_cached,
int btrfs_read_folio(struct file *file, struct folio *folio)
{
struct page *page = &folio->page;
- struct btrfs_inode *inode = BTRFS_I(page->mapping->host);
+ struct btrfs_inode *inode = page_to_inode(page);
u64 start = page_offset(page);
u64 end = start + PAGE_SIZE - 1;
struct btrfs_bio_ctrl bio_ctrl = { .opf = REQ_OP_READ };
+ struct extent_map *em_cached = NULL;
int ret;
btrfs_lock_and_flush_ordered_range(inode, start, end, NULL);
- ret = btrfs_do_readpage(page, NULL, &bio_ctrl, NULL);
+ ret = btrfs_do_readpage(page, &em_cached, &bio_ctrl, NULL);
+ free_extent_map(em_cached);
+
/*
* If btrfs_do_readpage() failed we will want to submit the assembled
* bio to do the cleanup.
@@ -1180,9 +1178,11 @@ static inline void contiguous_readpages(struct page *pages[], int nr_pages,
struct btrfs_bio_ctrl *bio_ctrl,
u64 *prev_em_start)
{
- struct btrfs_inode *inode = BTRFS_I(pages[0]->mapping->host);
+ struct btrfs_inode *inode = page_to_inode(pages[0]);
int index;
+ ASSERT(em_cached);
+
btrfs_lock_and_flush_ordered_range(inode, start, end, NULL);
for (index = 0; index < nr_pages; index++) {
@@ -1371,7 +1371,7 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
continue;
}
- em = btrfs_get_extent(inode, NULL, 0, cur, len);
+ em = btrfs_get_extent(inode, NULL, cur, len);
if (IS_ERR(em)) {
ret = PTR_ERR_OR_ZERO(em);
goto out_error;
@@ -1739,10 +1739,10 @@ static noinline_for_stack void write_one_eb(struct extent_buffer *eb,
folio_lock(folio);
folio_clear_dirty_for_io(folio);
folio_start_writeback(folio);
- ret = bio_add_folio(&bbio->bio, folio, folio_size(folio), 0);
+ ret = bio_add_folio(&bbio->bio, folio, eb->folio_size, 0);
ASSERT(ret);
wbc_account_cgroup_owner(wbc, folio_page(folio, 0),
- folio_size(folio));
+ eb->folio_size);
wbc->nr_to_write -= folio_nr_pages(folio);
folio_unlock(folio);
}
@@ -1766,7 +1766,7 @@ static noinline_for_stack void write_one_eb(struct extent_buffer *eb,
*/
static int submit_eb_subpage(struct page *page, struct writeback_control *wbc)
{
- struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
+ struct btrfs_fs_info *fs_info = page_to_fs_info(page);
struct folio *folio = page_folio(page);
int submitted = 0;
u64 page_start = page_offset(page);
@@ -1857,7 +1857,7 @@ static int submit_eb_page(struct page *page, struct btrfs_eb_write_context *ctx)
if (!folio_test_private(folio))
return 0;
- if (btrfs_sb(page->mapping->host->i_sb)->nodesize < PAGE_SIZE)
+ if (page_to_fs_info(page)->nodesize < PAGE_SIZE)
return submit_eb_subpage(page, wbc);
spin_lock(&mapping->i_private_lock);
@@ -1915,7 +1915,7 @@ int btree_write_cache_pages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct btrfs_eb_write_context ctx = { .wbc = wbc };
- struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
+ struct btrfs_fs_info *fs_info = inode_to_fs_info(mapping->host);
int ret = 0;
int done = 0;
int nr_to_write_done = 0;
@@ -2203,7 +2203,7 @@ void extent_write_locked_range(struct inode *inode, struct page *locked_page,
bool found_error = false;
int ret = 0;
struct address_space *mapping = inode->i_mapping;
- struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
const u32 sectorsize = fs_info->sectorsize;
loff_t i_size = i_size_read(inode);
u64 cur = start;
@@ -2309,7 +2309,7 @@ int extent_invalidate_folio(struct extent_io_tree *tree,
struct extent_state *cached_state = NULL;
u64 start = folio_pos(folio);
u64 end = start + folio_size(folio) - 1;
- size_t blocksize = folio->mapping->host->i_sb->s_blocksize;
+ size_t blocksize = folio_to_fs_info(folio)->sectorsize;
/* This function is only called for the btree inode */
ASSERT(tree->owner == IO_TREE_BTREE_INODE_IO);
@@ -2378,7 +2378,7 @@ int try_release_extent_mapping(struct page *page, gfp_t mask)
struct extent_map *em;
u64 start = page_offset(page);
u64 end = start + PAGE_SIZE - 1;
- struct btrfs_inode *btrfs_inode = BTRFS_I(page->mapping->host);
+ struct btrfs_inode *btrfs_inode = page_to_inode(page);
struct extent_io_tree *tree = &btrfs_inode->io_tree;
struct extent_map_tree *map = &btrfs_inode->extent_tree;
@@ -2453,12 +2453,65 @@ next:
return try_release_extent_state(tree, page, mask);
}
+struct btrfs_fiemap_entry {
+ u64 offset;
+ u64 phys;
+ u64 len;
+ u32 flags;
+};
+
/*
- * To cache previous fiemap extent
+ * Indicate the caller of emit_fiemap_extent() that it needs to unlock the file
+ * range from the inode's io tree, unlock the subvolume tree search path, flush
+ * the fiemap cache and relock the file range and research the subvolume tree.
+ * The value here is something negative that can't be confused with a valid
+ * errno value and different from 1 because that's also a return value from
+ * fiemap_fill_next_extent() and also it's often used to mean some btree search
+ * did not find a key, so make it some distinct negative value.
+ */
+#define BTRFS_FIEMAP_FLUSH_CACHE (-(MAX_ERRNO + 1))
+
+/*
+ * Used to:
+ *
+ * - Cache the next entry to be emitted to the fiemap buffer, so that we can
+ * merge extents that are contiguous and can be grouped as a single one;
*
- * Will be used for merging fiemap extent
+ * - Store extents ready to be written to the fiemap buffer in an intermediary
+ * buffer. This intermediary buffer is to ensure that in case the fiemap
+ * buffer is memory mapped to the fiemap target file, we don't deadlock
+ * during btrfs_page_mkwrite(). This is because during fiemap we are locking
+ * an extent range in order to prevent races with delalloc flushing and
+ * ordered extent completion, which is needed in order to reliably detect
+ * delalloc in holes and prealloc extents. And this can lead to a deadlock
+ * if the fiemap buffer is memory mapped to the file we are running fiemap
+ * against (a silly, useless in practice scenario, but possible) because
+ * btrfs_page_mkwrite() will try to lock the same extent range.
*/
struct fiemap_cache {
+ /* An array of ready fiemap entries. */
+ struct btrfs_fiemap_entry *entries;
+ /* Number of entries in the entries array. */
+ int entries_size;
+ /* Index of the next entry in the entries array to write to. */
+ int entries_pos;
+ /*
+ * Once the entries array is full, this indicates what's the offset for
+ * the next file extent item we must search for in the inode's subvolume
+ * tree after unlocking the extent range in the inode's io tree and
+ * releasing the search path.
+ */
+ u64 next_search_offset;
+ /*
+ * This matches struct fiemap_extent_info::fi_mapped_extents, we use it
+ * to count ourselves emitted extents and stop instead of relying on
+ * fiemap_fill_next_extent() because we buffer ready fiemap entries at
+ * the @entries array, and we want to stop as soon as we hit the max
+ * amount of extents to map, not just to save time but also to make the
+ * logic at extent_fiemap() simpler.
+ */
+ unsigned int extents_mapped;
+ /* Fields for the cached extent (unsubmitted, not ready, extent). */
u64 offset;
u64 phys;
u64 len;
@@ -2466,6 +2519,28 @@ struct fiemap_cache {
bool cached;
};
+static int flush_fiemap_cache(struct fiemap_extent_info *fieinfo,
+ struct fiemap_cache *cache)
+{
+ for (int i = 0; i < cache->entries_pos; i++) {
+ struct btrfs_fiemap_entry *entry = &cache->entries[i];
+ int ret;
+
+ ret = fiemap_fill_next_extent(fieinfo, entry->offset,
+ entry->phys, entry->len,
+ entry->flags);
+ /*
+ * Ignore 1 (reached max entries) because we keep track of that
+ * ourselves in emit_fiemap_extent().
+ */
+ if (ret < 0)
+ return ret;
+ }
+ cache->entries_pos = 0;
+
+ return 0;
+}
+
/*
* Helper to submit fiemap extent.
*
@@ -2480,8 +2555,8 @@ static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
struct fiemap_cache *cache,
u64 offset, u64 phys, u64 len, u32 flags)
{
+ struct btrfs_fiemap_entry *entry;
u64 cache_end;
- int ret = 0;
/* Set at the end of extent_fiemap(). */
ASSERT((flags & FIEMAP_EXTENT_LAST) == 0);
@@ -2494,7 +2569,9 @@ static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
* find an extent that starts at an offset behind the end offset of the
* previous extent we processed. This happens if fiemap is called
* without FIEMAP_FLAG_SYNC and there are ordered extents completing
- * while we call btrfs_next_leaf() (through fiemap_next_leaf_item()).
+ * after we had to unlock the file range, release the search path, emit
+ * the fiemap extents stored in the buffer (cache->entries array) and
+ * the lock the remainder of the range and re-search the btree.
*
* For example we are in leaf X processing its last item, which is the
* file extent item for file range [512K, 1M[, and after
@@ -2607,11 +2684,35 @@ static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
emit:
/* Not mergeable, need to submit cached one */
- ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
- cache->len, cache->flags);
- cache->cached = false;
- if (ret)
- return ret;
+
+ if (cache->entries_pos == cache->entries_size) {
+ /*
+ * We will need to research for the end offset of the last
+ * stored extent and not from the current offset, because after
+ * unlocking the range and releasing the path, if there's a hole
+ * between that end offset and this current offset, a new extent
+ * may have been inserted due to a new write, so we don't want
+ * to miss it.
+ */
+ entry = &cache->entries[cache->entries_size - 1];
+ cache->next_search_offset = entry->offset + entry->len;
+ cache->cached = false;
+
+ return BTRFS_FIEMAP_FLUSH_CACHE;
+ }
+
+ entry = &cache->entries[cache->entries_pos];
+ entry->offset = cache->offset;
+ entry->phys = cache->phys;
+ entry->len = cache->len;
+ entry->flags = cache->flags;
+ cache->entries_pos++;
+ cache->extents_mapped++;
+
+ if (cache->extents_mapped == fieinfo->fi_extents_max) {
+ cache->cached = false;
+ return 1;
+ }
assign:
cache->cached = true;
cache->offset = offset;
@@ -2651,7 +2752,7 @@ static int emit_last_fiemap_cache(struct fiemap_extent_info *fieinfo,
static int fiemap_next_leaf_item(struct btrfs_inode *inode, struct btrfs_path *path)
{
- struct extent_buffer *clone;
+ struct extent_buffer *clone = path->nodes[0];
struct btrfs_key key;
int slot;
int ret;
@@ -2660,29 +2761,45 @@ static int fiemap_next_leaf_item(struct btrfs_inode *inode, struct btrfs_path *p
if (path->slots[0] < btrfs_header_nritems(path->nodes[0]))
return 0;
+ /*
+ * Add a temporary extra ref to an already cloned extent buffer to
+ * prevent btrfs_next_leaf() freeing it, we want to reuse it to avoid
+ * the cost of allocating a new one.
+ */
+ ASSERT(test_bit(EXTENT_BUFFER_UNMAPPED, &clone->bflags));
+ atomic_inc(&clone->refs);
+
ret = btrfs_next_leaf(inode->root, path);
if (ret != 0)
- return ret;
+ goto out;
/*
* Don't bother with cloning if there are no more file extent items for
* our inode.
*/
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
- if (key.objectid != btrfs_ino(inode) || key.type != BTRFS_EXTENT_DATA_KEY)
- return 1;
+ if (key.objectid != btrfs_ino(inode) || key.type != BTRFS_EXTENT_DATA_KEY) {
+ ret = 1;
+ goto out;
+ }
/* See the comment at fiemap_search_slot() about why we clone. */
- clone = btrfs_clone_extent_buffer(path->nodes[0]);
- if (!clone)
- return -ENOMEM;
+ copy_extent_buffer_full(clone, path->nodes[0]);
+ /*
+ * Important to preserve the start field, for the optimizations when
+ * checking if extents are shared (see extent_fiemap()).
+ */
+ clone->start = path->nodes[0]->start;
slot = path->slots[0];
btrfs_release_path(path);
path->nodes[0] = clone;
path->slots[0] = slot;
+out:
+ if (ret)
+ free_extent_buffer(clone);
- return 0;
+ return ret;
}
/*
@@ -2737,8 +2854,8 @@ static int fiemap_search_slot(struct btrfs_inode *inode, struct btrfs_path *path
* neighbour leaf).
* We also need the private clone because holding a read lock on an
* extent buffer of the subvolume's b+tree will make lockdep unhappy
- * when we call fiemap_fill_next_extent(), because that may cause a page
- * fault when filling the user space buffer with fiemap data.
+ * when we check if extents are shared, as backref walking may need to
+ * lock the same leaf we are processing.
*/
clone = btrfs_clone_extent_buffer(path->nodes[0]);
if (!clone)
@@ -2778,34 +2895,16 @@ static int fiemap_process_hole(struct btrfs_inode *inode,
* it beyond i_size.
*/
while (cur_offset < end && cur_offset < i_size) {
- struct extent_state *cached_state = NULL;
u64 delalloc_start;
u64 delalloc_end;
u64 prealloc_start;
- u64 lockstart;
- u64 lockend;
u64 prealloc_len = 0;
bool delalloc;
- lockstart = round_down(cur_offset, inode->root->fs_info->sectorsize);
- lockend = round_up(end, inode->root->fs_info->sectorsize);
-
- /*
- * We are only locking for the delalloc range because that's the
- * only thing that can change here. With fiemap we have a lock
- * on the inode, so no buffered or direct writes can happen.
- *
- * However mmaps and normal page writeback will cause this to
- * change arbitrarily. We have to lock the extent lock here to
- * make sure that nobody messes with the tree while we're doing
- * btrfs_find_delalloc_in_range.
- */
- lock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
delalloc = btrfs_find_delalloc_in_range(inode, cur_offset, end,
delalloc_cached_state,
&delalloc_start,
&delalloc_end);
- unlock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
if (!delalloc)
break;
@@ -2973,6 +3072,7 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
u64 start, u64 len)
{
const u64 ino = btrfs_ino(inode);
+ struct extent_state *cached_state = NULL;
struct extent_state *delalloc_cached_state = NULL;
struct btrfs_path *path;
struct fiemap_cache cache = { 0 };
@@ -2985,26 +3085,33 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
bool stopped = false;
int ret;
+ cache.entries_size = PAGE_SIZE / sizeof(struct btrfs_fiemap_entry);
+ cache.entries = kmalloc_array(cache.entries_size,
+ sizeof(struct btrfs_fiemap_entry),
+ GFP_KERNEL);
backref_ctx = btrfs_alloc_backref_share_check_ctx();
path = btrfs_alloc_path();
- if (!backref_ctx || !path) {
+ if (!cache.entries || !backref_ctx || !path) {
ret = -ENOMEM;
goto out;
}
+restart:
range_start = round_down(start, sectorsize);
range_end = round_up(start + len, sectorsize);
prev_extent_end = range_start;
+ lock_extent(&inode->io_tree, range_start, range_end, &cached_state);
+
ret = fiemap_find_last_extent_offset(inode, path, &last_extent_end);
if (ret < 0)
- goto out;
+ goto out_unlock;
btrfs_release_path(path);
path->reada = READA_FORWARD;
ret = fiemap_search_slot(inode, path, range_start);
if (ret < 0) {
- goto out;
+ goto out_unlock;
} else if (ret > 0) {
/*
* No file extent item found, but we may have delalloc between
@@ -3051,7 +3158,7 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
backref_ctx, 0, 0, 0,
prev_extent_end, hole_end);
if (ret < 0) {
- goto out;
+ goto out_unlock;
} else if (ret > 0) {
/* fiemap_fill_next_extent() told us to stop. */
stopped = true;
@@ -3107,7 +3214,7 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
extent_gen,
backref_ctx);
if (ret < 0)
- goto out;
+ goto out_unlock;
else if (ret > 0)
flags |= FIEMAP_EXTENT_SHARED;
}
@@ -3118,9 +3225,9 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
}
if (ret < 0) {
- goto out;
+ goto out_unlock;
} else if (ret > 0) {
- /* fiemap_fill_next_extent() told us to stop. */
+ /* emit_fiemap_extent() told us to stop. */
stopped = true;
break;
}
@@ -3129,12 +3236,12 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
next_item:
if (fatal_signal_pending(current)) {
ret = -EINTR;
- goto out;
+ goto out_unlock;
}
ret = fiemap_next_leaf_item(inode, path);
if (ret < 0) {
- goto out;
+ goto out_unlock;
} else if (ret > 0) {
/* No more file extent items for this inode. */
break;
@@ -3143,22 +3250,12 @@ next_item:
}
check_eof_delalloc:
- /*
- * Release (and free) the path before emitting any final entries to
- * fiemap_fill_next_extent() to keep lockdep happy. This is because
- * once we find no more file extent items exist, we may have a
- * non-cloned leaf, and fiemap_fill_next_extent() can trigger page
- * faults when copying data to the user space buffer.
- */
- btrfs_free_path(path);
- path = NULL;
-
if (!stopped && prev_extent_end < range_end) {
ret = fiemap_process_hole(inode, fieinfo, &cache,
&delalloc_cached_state, backref_ctx,
0, 0, 0, prev_extent_end, range_end - 1);
if (ret < 0)
- goto out;
+ goto out_unlock;
prev_extent_end = range_end;
}
@@ -3166,28 +3263,16 @@ check_eof_delalloc:
const u64 i_size = i_size_read(&inode->vfs_inode);
if (prev_extent_end < i_size) {
- struct extent_state *cached_state = NULL;
u64 delalloc_start;
u64 delalloc_end;
- u64 lockstart;
- u64 lockend;
bool delalloc;
- lockstart = round_down(prev_extent_end, sectorsize);
- lockend = round_up(i_size, sectorsize);
-
- /*
- * See the comment in fiemap_process_hole as to why
- * we're doing the locking here.
- */
- lock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
delalloc = btrfs_find_delalloc_in_range(inode,
prev_extent_end,
i_size - 1,
&delalloc_cached_state,
&delalloc_start,
&delalloc_end);
- unlock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
if (!delalloc)
cache.flags |= FIEMAP_EXTENT_LAST;
} else {
@@ -3195,9 +3280,39 @@ check_eof_delalloc:
}
}
+out_unlock:
+ unlock_extent(&inode->io_tree, range_start, range_end, &cached_state);
+
+ if (ret == BTRFS_FIEMAP_FLUSH_CACHE) {
+ btrfs_release_path(path);
+ ret = flush_fiemap_cache(fieinfo, &cache);
+ if (ret)
+ goto out;
+ len -= cache.next_search_offset - start;
+ start = cache.next_search_offset;
+ goto restart;
+ } else if (ret < 0) {
+ goto out;
+ }
+
+ /*
+ * Must free the path before emitting to the fiemap buffer because we
+ * may have a non-cloned leaf and if the fiemap buffer is memory mapped
+ * to a file, a write into it (through btrfs_page_mkwrite()) may trigger
+ * waiting for an ordered extent that in order to complete needs to
+ * modify that leaf, therefore leading to a deadlock.
+ */
+ btrfs_free_path(path);
+ path = NULL;
+
+ ret = flush_fiemap_cache(fieinfo, &cache);
+ if (ret)
+ goto out;
+
ret = emit_last_fiemap_cache(fieinfo, &cache);
out:
free_extent_state(delalloc_cached_state);
+ kfree(cache.entries);
btrfs_free_backref_share_ctx(backref_ctx);
btrfs_free_path(path);
return ret;
@@ -3646,7 +3761,7 @@ retry:
/* For now, we should only have single-page folios for btree inode. */
ASSERT(folio_nr_pages(existing_folio) == 1);
- if (folio_size(existing_folio) != folio_size(eb->folios[0])) {
+ if (folio_size(existing_folio) != eb->folio_size) {
folio_unlock(existing_folio);
folio_put(existing_folio);
return -EAGAIN;
@@ -3789,6 +3904,8 @@ reallocate:
* and free the allocated page.
*/
folio = eb->folios[i];
+ eb->folio_size = folio_size(folio);
+ eb->folio_shift = folio_shift(folio);
spin_lock(&mapping->i_private_lock);
/* Should not fail, as we have preallocated the memory */
ret = attach_extent_buffer_folio(eb, folio, prealloc);
@@ -4238,7 +4355,7 @@ int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
for (int i = 0; i < num_folios; i++) {
struct folio *folio = eb->folios[i];
- ret = bio_add_folio(&bbio->bio, folio, folio_size(folio), 0);
+ ret = bio_add_folio(&bbio->bio, folio, eb->folio_size, 0);
ASSERT(ret);
}
}
@@ -4258,7 +4375,7 @@ static bool report_eb_range(const struct extent_buffer *eb, unsigned long start,
unsigned long len)
{
btrfs_warn(eb->fs_info,
- "access to eb bytenr %llu len %lu out of range start %lu len %lu",
+ "access to eb bytenr %llu len %u out of range start %lu len %lu",
eb->start, eb->len, start, len);
WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
@@ -4287,7 +4404,7 @@ static inline int check_eb_range(const struct extent_buffer *eb,
void read_extent_buffer(const struct extent_buffer *eb, void *dstv,
unsigned long start, unsigned long len)
{
- const int unit_size = folio_size(eb->folios[0]);
+ const int unit_size = eb->folio_size;
size_t cur;
size_t offset;
char *dst = (char *)dstv;
@@ -4327,7 +4444,7 @@ int read_extent_buffer_to_user_nofault(const struct extent_buffer *eb,
void __user *dstv,
unsigned long start, unsigned long len)
{
- const int unit_size = folio_size(eb->folios[0]);
+ const int unit_size = eb->folio_size;
size_t cur;
size_t offset;
char __user *dst = (char __user *)dstv;
@@ -4367,7 +4484,7 @@ int read_extent_buffer_to_user_nofault(const struct extent_buffer *eb,
int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
unsigned long start, unsigned long len)
{
- const int unit_size = folio_size(eb->folios[0]);
+ const int unit_size = eb->folio_size;
size_t cur;
size_t offset;
char *kaddr;
@@ -4438,7 +4555,7 @@ static void __write_extent_buffer(const struct extent_buffer *eb,
const void *srcv, unsigned long start,
unsigned long len, bool use_memmove)
{
- const int unit_size = folio_size(eb->folios[0]);
+ const int unit_size = eb->folio_size;
size_t cur;
size_t offset;
char *kaddr;
@@ -4487,7 +4604,7 @@ void write_extent_buffer(const struct extent_buffer *eb, const void *srcv,
static void memset_extent_buffer(const struct extent_buffer *eb, int c,
unsigned long start, unsigned long len)
{
- const int unit_size = folio_size(eb->folios[0]);
+ const int unit_size = eb->folio_size;
unsigned long cur = start;
if (eb->addr) {
@@ -4518,7 +4635,7 @@ void memzero_extent_buffer(const struct extent_buffer *eb, unsigned long start,
void copy_extent_buffer_full(const struct extent_buffer *dst,
const struct extent_buffer *src)
{
- const int unit_size = folio_size(src->folios[0]);
+ const int unit_size = src->folio_size;
unsigned long cur = 0;
ASSERT(dst->len == src->len);
@@ -4540,7 +4657,7 @@ void copy_extent_buffer(const struct extent_buffer *dst,
unsigned long dst_offset, unsigned long src_offset,
unsigned long len)
{
- const int unit_size = folio_size(dst->folios[0]);
+ const int unit_size = dst->folio_size;
u64 dst_len = dst->len;
size_t cur;
size_t offset;
@@ -4596,10 +4713,10 @@ static inline void eb_bitmap_offset(const struct extent_buffer *eb,
* the bitmap item in the extent buffer + the offset of the byte in the
* bitmap item.
*/
- offset = start + offset_in_folio(eb->folios[0], eb->start) + byte_offset;
+ offset = start + offset_in_eb_folio(eb, eb->start) + byte_offset;
- *folio_index = offset >> folio_shift(eb->folios[0]);
- *folio_offset = offset_in_folio(eb->folios[0], offset);
+ *folio_index = offset >> eb->folio_shift;
+ *folio_offset = offset_in_eb_folio(eb, offset);
}
/*
@@ -4713,7 +4830,7 @@ void memcpy_extent_buffer(const struct extent_buffer *dst,
unsigned long dst_offset, unsigned long src_offset,
unsigned long len)
{
- const int unit_size = folio_size(dst->folios[0]);
+ const int unit_size = dst->folio_size;
unsigned long cur_off = 0;
if (check_eb_range(dst, dst_offset, len) ||
@@ -4837,7 +4954,7 @@ out:
static int try_release_subpage_extent_buffer(struct page *page)
{
- struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
+ struct btrfs_fs_info *fs_info = page_to_fs_info(page);
u64 cur = page_offset(page);
const u64 end = page_offset(page) + PAGE_SIZE;
int ret;
@@ -4910,7 +5027,7 @@ int try_release_extent_buffer(struct page *page)
struct folio *folio = page_folio(page);
struct extent_buffer *eb;
- if (btrfs_sb(page->mapping->host->i_sb)->nodesize < PAGE_SIZE)
+ if (page_to_fs_info(page)->nodesize < PAGE_SIZE)
return try_release_subpage_extent_buffer(page);
/*
generated by cgit v1.2.3 (git 2.39.0) at 2025-11-04 07:03:31 +0300