* [PATCH] erofs-utils: fsck: add concurrent extraction and decompression
@ 2026-07-02 8:10 Nithurshen
2026-07-02 12:54 ` Gao Xiang
0 siblings, 1 reply; 4+ messages in thread
From: Nithurshen @ 2026-07-02 8:10 UTC (permalink / raw)
To: linux-erofs; +Cc: nithurshen.dev, xiang, hsiangkao
This patch introduces a multi-threaded pipeline for fsck.erofs,
combining parallel directory traversal with background pcluster
decompression to significantly reduce extraction time.
Key architectural changes include:
- Thread-Safe State: Removes the global dirstack array and
fsckcfg.extract_path. These are replaced with per-task localized
paths and thread-local linked lists to eliminate data races.
- Concurrent Traversal: Refactors erofsfsck_dirent_iter to allocate
task structures and dispatch inode processing to a background
workqueue (z_erofs_mt_wq).
- Asynchronous Decompression: Introduces z_erofs_mt_read_ctx to
batch pcluster reads and decouple decompression from main I/O.
Limits batch size dynamically (32 for LZ4, 8 for compute-heavy
algorithms) to balance CPU cache hits and memory overhead.
- Memory & Deadlock Safety: Implements inline backpressure during
directory iteration. If pending inodes exceed workqueue capacity,
execution falls back to synchronous processing to prevent
recursive thread-pool starvation and unbounded memory growth.
- Synchronization Primitives: Adds portable condition variable
wrappers (erofs_cond_t) to ensure the main thread safely waits
for all pending background inodes before exiting.
Signed-off-by: Nithurshen <nithurshen.dev@gmail.com>
---
fsck/main.c | 446 ++++++++++++++++++++++++---------------
include/erofs/cond.h | 31 +++
include/erofs/internal.h | 15 +-
include/erofs/lock.h | 3 +
lib/data.c | 248 +++++++++++++++++-----
5 files changed, 525 insertions(+), 218 deletions(-)
create mode 100644 include/erofs/cond.h
diff --git a/fsck/main.c b/fsck/main.c
index 16cc627..15500ce 100644
--- a/fsck/main.c
+++ b/fsck/main.c
@@ -8,23 +8,43 @@
#include <time.h>
#include <utime.h>
#include <unistd.h>
+#include "erofs/lock.h"
#include <sys/stat.h>
#include "erofs/print.h"
#include "erofs/decompress.h"
#include "erofs/dir.h"
#include "erofs/xattr.h"
+#include "erofs/workqueue.h"
#include "../lib/compressor.h"
#include "../lib/liberofs_compress.h"
-static int erofsfsck_check_inode(erofs_nid_t pnid, erofs_nid_t nid);
-
struct erofsfsck_dirstack {
- erofs_nid_t dirs[PATH_MAX];
- int top;
+ erofs_nid_t nid;
+ struct erofsfsck_dirstack *parent;
+ int depth;
};
+static int erofsfsck_check_inode(erofs_nid_t pnid, erofs_nid_t nid, const char *path,
+ struct erofsfsck_dirstack *dirstack);
+
+#ifdef EROFS_MT_ENABLED
+static EROFS_DEFINE_MUTEX(erofsfsck_mt_lock);
+static erofs_cond_t erofsfsck_mt_cond;
+static int erofsfsck_pending_inodes = 0;
+static int erofsfsck_global_err = 0;
+extern struct erofs_workqueue z_erofs_mt_wq;
+static struct erofs_workqueue erofsfsck_wq;
+
+struct erofsfsck_inode_task {
+ struct erofs_work work;
+ erofs_nid_t pnid;
+ erofs_nid_t nid;
+ char *path;
+ struct erofsfsck_dirstack *dirstack;
+};
+#endif
+
struct erofsfsck_cfg {
- struct erofsfsck_dirstack dirstack;
u64 physical_blocks;
u64 logical_blocks;
char *extract_path;
@@ -306,7 +326,7 @@ static void erofsfsck_set_attributes(struct erofs_inode *inode, char *path)
int ret;
/* don't apply attributes when fsck is used without extraction */
- if (!fsckcfg.extract_path)
+ if (!path)
return;
#ifdef HAVE_UTIMENSAT
@@ -509,32 +529,27 @@ static int erofs_verify_inode_data(struct erofs_inode *inode, int outfd)
.buf = __EROFS_BUF_INITIALIZER,
};
bool needdecode = fsckcfg.check_decomp && !erofs_is_packed_inode(inode);
- int ret = 0;
+ int ret = 0, wait_err;
bool compressed;
erofs_off_t pos = 0;
u64 pchunk_len = 0;
- unsigned int raw_size = 0, buffer_size = 0;
- char *raw = NULL, *buffer = NULL;
+ struct z_erofs_mt_read_ctx *ctx;
erofs_dbg("verify data chunk of nid(%llu): type(%d)",
- inode->nid | 0ULL, inode->datalayout);
+ inode->nid | 0ULL, inode->datalayout);
+ ctx = z_erofs_mt_read_ctx_alloc(outfd, true);
+ if (!ctx)
+ return -ENOMEM;
+
compressed = erofs_inode_is_data_compressed(inode->datalayout);
- while (pos < inode->i_size) {
- unsigned int alloc_rawsize;
+ while (pos < inode->i_size) {
map.m_la = pos;
ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_FIEMAP);
if (ret)
goto out;
- if (!compressed && map.m_llen != map.m_plen) {
- erofs_err("broken chunk length m_la %" PRIu64 " m_llen %" PRIu64 " m_plen %" PRIu64,
- map.m_la, map.m_llen, map.m_plen);
- ret = -EFSCORRUPTED;
- goto out;
- }
-
/* the last lcluster can be divided into 3 parts */
if (map.m_la + map.m_llen > inode->i_size)
map.m_llen = inode->i_size - map.m_la;
@@ -555,92 +570,60 @@ static int erofs_verify_inode_data(struct erofs_inode *inode, int outfd)
continue;
}
- if (map.m_plen > Z_EROFS_PCLUSTER_MAX_SIZE) {
- if (compressed && !(map.m_flags & __EROFS_MAP_FRAGMENT)) {
- erofs_err("invalid pcluster size %" PRIu64 " @ offset %" PRIu64 " of nid %" PRIu64,
- map.m_plen, map.m_la,
- inode->nid | 0ULL);
- ret = -EFSCORRUPTED;
- goto out;
- }
- alloc_rawsize = Z_EROFS_PCLUSTER_MAX_SIZE;
- } else {
- alloc_rawsize = map.m_plen;
- }
-
- if (alloc_rawsize > raw_size) {
- char *newraw = realloc(raw, alloc_rawsize);
-
- if (!newraw) {
+ if (compressed) {
+ size_t buffer_size = map.m_llen > erofs_blksiz(inode->sbi) ?
+ map.m_llen : erofs_blksiz(inode->sbi);
+ char *raw, *buffer;
+ raw = malloc(map.m_plen);
+ buffer = calloc(1, buffer_size);
+
+ if (!raw || !buffer) {
+ free(raw);
+ free(buffer);
ret = -ENOMEM;
goto out;
}
- raw = newraw;
- raw_size = alloc_rawsize;
- }
- if (compressed) {
- if (map.m_llen > buffer_size) {
- char *newbuffer;
-
- buffer_size = map.m_llen;
- newbuffer = realloc(buffer, buffer_size);
- if (!newbuffer) {
- ret = -ENOMEM;
- goto out;
- }
- buffer = newbuffer;
+ ret = z_erofs_read_one_data(inode, &map, raw, buffer, 0, map.m_llen,
+ false, map.m_la, ctx);
+ if (ret) {
+ goto out;
}
- ret = z_erofs_read_one_data(inode, &map, raw, buffer,
- 0, map.m_llen, false);
+ } else {
+ char *raw = calloc(1, map.m_llen);
+ ret = erofs_read_one_data(inode, &map, raw, 0, map.m_llen);
+ if (ret >= 0 && outfd >= 0)
+ pwrite(outfd, raw, map.m_llen, map.m_la);
+ free(raw);
if (ret)
goto out;
-
- if (outfd >= 0 && write(outfd, buffer, map.m_llen) < 0)
- goto fail_eio;
- } else {
- u64 p = 0;
-
- do {
- u64 count = min_t(u64, alloc_rawsize,
- map.m_llen);
-
- ret = erofs_read_one_data(inode, &map, raw, p, count);
- if (ret)
- goto out;
-
- if (outfd >= 0 && write(outfd, raw, count) < 0)
- goto fail_eio;
- map.m_llen -= count;
- p += count;
- } while (map.m_llen);
}
}
+ z_erofs_mt_read_enqueue(ctx);
+
+out:
+ wait_err = z_erofs_mt_read_ctx_wait(ctx);
+ if (wait_err < 0 && ret >= 0)
+ ret = wait_err;
if (fsckcfg.print_comp_ratio) {
if (!erofs_is_packed_inode(inode))
fsckcfg.logical_blocks += BLK_ROUND_UP(inode->sbi, inode->i_size);
fsckcfg.physical_blocks += BLK_ROUND_UP(inode->sbi, pchunk_len);
}
-out:
- if (raw)
- free(raw);
- if (buffer)
- free(buffer);
- return ret < 0 ? ret : 0;
-fail_eio:
- erofs_err("I/O error occurred when verifying data chunk @ nid %llu",
- inode->nid | 0ULL);
- ret = -EIO;
- goto out;
+ if (outfd >= 0 && ret >= 0)
+ ftruncate(outfd, inode->i_size);
+
+ z_erofs_mt_read_ctx_free(ctx);
+ return ret < 0 ? ret : 0;
}
-static inline int erofs_extract_dir(struct erofs_inode *inode)
+static inline int erofs_extract_dir(struct erofs_inode *inode, const char* path)
{
int ret;
- erofs_dbg("create directory %s", fsckcfg.extract_path);
+ erofs_dbg("create directory %s", path);
/* verify data chunk layout */
ret = erofs_verify_inode_data(inode, -1);
@@ -653,19 +636,19 @@ static inline int erofs_extract_dir(struct erofs_inode *inode)
* write/execute permission. These are fixed up later in
* erofsfsck_set_attributes().
*/
- if (mkdir(fsckcfg.extract_path, 0700) < 0) {
+ if (mkdir(path, 0700) < 0) {
struct stat st;
if (errno != EEXIST) {
erofs_err("failed to create directory: %s (%s)",
- fsckcfg.extract_path, strerror(errno));
+ path, strerror(errno));
return -errno;
}
- if (lstat(fsckcfg.extract_path, &st) ||
+ if (lstat(path, &st) ||
!S_ISDIR(st.st_mode)) {
erofs_err("path is not a directory: %s",
- fsckcfg.extract_path);
+ path);
return -ENOTDIR;
}
@@ -673,9 +656,9 @@ static inline int erofs_extract_dir(struct erofs_inode *inode)
* Try to change permissions of existing directory so
* that we can write to it
*/
- if (chmod(fsckcfg.extract_path, 0700) < 0) {
+ if (chmod(path, 0700) < 0) {
erofs_err("failed to set permissions: %s (%s)",
- fsckcfg.extract_path, strerror(errno));
+ path, strerror(errno));
return -errno;
}
}
@@ -739,37 +722,37 @@ static void erofsfsck_hardlink_exit(void)
}
}
-static inline int erofs_extract_file(struct erofs_inode *inode)
+static inline int erofs_extract_file(struct erofs_inode *inode, const char* path)
{
bool tryagain = true;
int ret, fd;
- erofs_dbg("extract file to path: %s", fsckcfg.extract_path);
+ erofs_dbg("extract file to path: %s", path);
again:
- fd = open(fsckcfg.extract_path,
+ fd = open(path,
O_WRONLY | O_CREAT | O_NOFOLLOW |
(fsckcfg.overwrite ? O_TRUNC : O_EXCL), 0700);
if (fd < 0) {
if (fsckcfg.overwrite && tryagain) {
if (errno == EISDIR) {
erofs_warn("try to forcely remove directory %s",
- fsckcfg.extract_path);
- if (rmdir(fsckcfg.extract_path) < 0) {
+ path);
+ if (rmdir(path) < 0) {
erofs_err("failed to remove: %s (%s)",
- fsckcfg.extract_path, strerror(errno));
+ path, strerror(errno));
return -EISDIR;
}
} else if (errno == EACCES &&
- chmod(fsckcfg.extract_path, 0700) < 0) {
+ chmod(path, 0700) < 0) {
erofs_err("failed to set permissions: %s (%s)",
- fsckcfg.extract_path, strerror(errno));
+ path, strerror(errno));
return -errno;
}
tryagain = false;
goto again;
}
- erofs_err("failed to open: %s (%s)", fsckcfg.extract_path,
+ erofs_err("failed to open: %s (%s)", path,
strerror(errno));
return -errno;
}
@@ -780,14 +763,14 @@ again:
return ret;
}
-static inline int erofs_extract_symlink(struct erofs_inode *inode)
+static inline int erofs_extract_symlink(struct erofs_inode *inode, const char* path)
{
struct erofs_vfile vf;
bool tryagain = true;
int ret;
char *buf = NULL;
- erofs_dbg("extract symlink to path: %s", fsckcfg.extract_path);
+ erofs_dbg("extract symlink to path: %s", path);
/* verify data chunk layout */
ret = erofs_verify_inode_data(inode, -1);
@@ -813,13 +796,13 @@ static inline int erofs_extract_symlink(struct erofs_inode *inode)
buf[inode->i_size] = '\0';
again:
- if (symlink(buf, fsckcfg.extract_path) < 0) {
+ if (symlink(buf, path) < 0) {
if (errno == EEXIST && fsckcfg.overwrite && tryagain) {
erofs_warn("try to forcely remove file %s",
- fsckcfg.extract_path);
- if (unlink(fsckcfg.extract_path) < 0) {
+ path);
+ if (unlink(path) < 0) {
erofs_err("failed to remove: %s",
- fsckcfg.extract_path);
+ path);
ret = -errno;
goto out;
}
@@ -827,7 +810,7 @@ again:
goto again;
}
erofs_err("failed to create symlink: %s",
- fsckcfg.extract_path);
+ path);
ret = -errno;
}
out:
@@ -836,12 +819,12 @@ out:
return ret;
}
-static int erofs_extract_special(struct erofs_inode *inode)
+static int erofs_extract_special(struct erofs_inode *inode, const char* path)
{
bool tryagain = true;
int ret;
- erofs_dbg("extract special to path: %s", fsckcfg.extract_path);
+ erofs_dbg("extract special to path: %s", path);
/* verify data chunk layout */
ret = erofs_verify_inode_data(inode, -1);
@@ -849,13 +832,13 @@ static int erofs_extract_special(struct erofs_inode *inode)
return ret;
again:
- if (mknod(fsckcfg.extract_path, inode->i_mode, inode->u.i_rdev) < 0) {
+ if (mknod(path, inode->i_mode, inode->u.i_rdev) < 0) {
if (errno == EEXIST && fsckcfg.overwrite && tryagain) {
erofs_warn("try to forcely remove file %s",
- fsckcfg.extract_path);
- if (unlink(fsckcfg.extract_path) < 0) {
+ path);
+ if (unlink(path) < 0) {
erofs_err("failed to remove: %s",
- fsckcfg.extract_path);
+ path);
return -errno;
}
tryagain = false;
@@ -863,28 +846,73 @@ again:
}
if (errno == EEXIST || fsckcfg.superuser) {
erofs_err("failed to create special file: %s",
- fsckcfg.extract_path);
+ path);
ret = -errno;
} else {
erofs_warn("failed to create special file: %s, skipped",
- fsckcfg.extract_path);
+ path);
ret = -ECANCELED;
}
}
return ret;
}
-struct erofsfsck_get_parent_ctx {
+#ifdef EROFS_MT_ENABLED
+static void erofsfsck_inode_worker(struct erofs_work *work, void *tlsp)
+{
+ struct erofsfsck_inode_task *task = (struct erofsfsck_inode_task *)work;
+ int ret;
+
+ ret = erofsfsck_check_inode(task->pnid, task->nid, task->path, task->dirstack);
+
+ erofs_mutex_lock(&erofsfsck_mt_lock);
+ if (ret < 0 && !erofsfsck_global_err)
+ erofsfsck_global_err = ret;
+
+ erofsfsck_pending_inodes--;
+ if (erofsfsck_pending_inodes == 0)
+ erofs_cond_signal(&erofsfsck_mt_cond);
+ erofs_mutex_unlock(&erofsfsck_mt_lock);
+
+ struct erofsfsck_dirstack *curr = task->dirstack;
+ while (curr) {
+ struct erofsfsck_dirstack *next = curr->parent;
+ free(curr);
+ curr = next;
+ }
+ task->dirstack = NULL;
+
+ free(task->path);
+ free(task->dirstack);
+ free(task);
+}
+
+static void erofsfsck_wait_pending_inodes(void)
+{
+ erofs_mutex_lock(&erofsfsck_mt_lock);
+ while (erofsfsck_pending_inodes > 0)
+ erofs_cond_wait(&erofsfsck_mt_cond, &erofsfsck_mt_lock);
+
+ if (erofsfsck_global_err && !fsckcfg.corrupted)
+ fsckcfg.corrupted = true;
+ erofs_mutex_unlock(&erofsfsck_mt_lock);
+}
+#else
+static void erofsfsck_wait_pending_inodes(void) {}
+#endif
+
+struct erofsfsck_dir_context {
struct erofs_dir_context ctx;
- erofs_nid_t pnid;
+ const char *parent_path;
+ struct erofsfsck_dirstack *dirstack;
};
static int erofsfsck_get_parent_cb(struct erofs_dir_context *ctx)
{
- struct erofsfsck_get_parent_ctx *pctx = (void *)ctx;
+ struct erofsfsck_dir_context *dctx = (struct erofsfsck_dir_context *)ctx;
if (ctx->dot_dotdot && ctx->de_namelen == 2) {
- pctx->pnid = ctx->de_nid;
+ dctx->ctx.pnid = ctx->de_nid;
return 1;
}
return 0;
@@ -892,45 +920,89 @@ static int erofsfsck_get_parent_cb(struct erofs_dir_context *ctx)
static int erofsfsck_dirent_iter(struct erofs_dir_context *ctx)
{
- int ret;
- size_t prev_pos, curr_pos;
+ struct erofsfsck_dir_context *dctx = (struct erofsfsck_dir_context *)ctx;
+ int ret = 0;
+ char *path = NULL;
if (ctx->dot_dotdot)
return 0;
- prev_pos = fsckcfg.extract_pos;
- curr_pos = prev_pos;
+ if (dctx->parent_path) {
+ size_t plen = strlen(dctx->parent_path);
+ if (plen + 1 + ctx->de_namelen >= PATH_MAX)
+ return -ENAMETOOLONG;
- if (prev_pos + ctx->de_namelen >= PATH_MAX) {
- erofs_err("unable to fsck since the path is too long (%llu)",
- (curr_pos + ctx->de_namelen) | 0ULL);
- return -EOPNOTSUPP;
+ path = malloc(plen + 1 + ctx->de_namelen + 1);
+ if (!path)
+ return -ENOMEM;
+ snprintf(path, PATH_MAX, "%s/%.*s", dctx->parent_path,
+ (int)ctx->de_namelen, ctx->dname);
}
- if (fsckcfg.extract_path) {
- fsckcfg.extract_path[curr_pos++] = '/';
- strncpy(fsckcfg.extract_path + curr_pos, ctx->dname,
- ctx->de_namelen);
- curr_pos += ctx->de_namelen;
- fsckcfg.extract_path[curr_pos] = '\0';
+#ifdef EROFS_MT_ENABLED
+ bool queue_full = false;
+
+ erofs_mutex_lock(&erofsfsck_mt_lock);
+ /* Backpressure: Prevent recursive thread-pool deadlock */
+ if (erofsfsck_pending_inodes >= erofsfsck_wq.max_jobs) {
+ queue_full = true;
} else {
- curr_pos += ctx->de_namelen;
+ erofsfsck_pending_inodes++;
}
- fsckcfg.extract_pos = curr_pos;
- ret = erofsfsck_check_inode(ctx->dir->nid, ctx->de_nid);
+ erofs_mutex_unlock(&erofsfsck_mt_lock);
+
+ /* If space is available, offload to background workers */
+ if (!queue_full) {
+ struct erofsfsck_inode_task *task = calloc(1, sizeof(*task));
+ if (!task) {
+ erofs_mutex_lock(&erofsfsck_mt_lock);
+ erofsfsck_pending_inodes--;
+ erofs_mutex_unlock(&erofsfsck_mt_lock);
+ free(path);
+ return -ENOMEM;
+ }
- if (fsckcfg.extract_path)
- fsckcfg.extract_path[prev_pos] = '\0';
- fsckcfg.extract_pos = prev_pos;
+ task->pnid = ctx->dir->nid;
+ task->nid = ctx->de_nid;
+ task->path = path;
+
+ if (dctx->dirstack) {
+ struct erofsfsck_dirstack *src = dctx->dirstack;
+ struct erofsfsck_dirstack *new_node = NULL;
+ struct erofsfsck_dirstack *prev_node = NULL;
+
+ // Build the stack from the bottom up to preserve order
+ while (src) {
+ new_node = malloc(sizeof(struct erofsfsck_dirstack));
+ if (!new_node) break;
+
+ new_node->nid = src->nid;
+ new_node->depth = src->depth;
+ new_node->parent = prev_node;
+
+ prev_node = new_node;
+ src = src->parent;
+ }
+ task->dirstack = prev_node;
+ }
+ task->work.fn = erofsfsck_inode_worker;
+ erofs_queue_work(&erofsfsck_wq, &task->work);
+ return 0;
+}
+#endif
+
+ /* Fallback: Execute synchronously if MT disabled or queue is full */
+ ret = erofsfsck_check_inode(ctx->dir->nid, ctx->de_nid, path, dctx->dirstack);
+ free(path);
return ret;
}
-static int erofsfsck_extract_inode(struct erofs_inode *inode)
+static int erofsfsck_extract_inode(struct erofs_inode *inode, const char *path)
{
int ret;
char *oldpath;
- if (!fsckcfg.extract_path || erofs_is_packed_inode(inode)) {
+ if (!path || erofs_is_packed_inode(inode)) {
verify:
/* verify data chunk layout */
return erofs_verify_inode_data(inode, -1);
@@ -938,9 +1010,9 @@ verify:
oldpath = erofsfsck_hardlink_find(inode->nid);
if (oldpath) {
- if (link(oldpath, fsckcfg.extract_path) == -1) {
+ if (link(oldpath, path) == -1) {
erofs_err("failed to extract hard link: %s (%s)",
- fsckcfg.extract_path, strerror(errno));
+ path, strerror(errno));
return -errno;
}
return 0;
@@ -948,19 +1020,19 @@ verify:
switch (inode->i_mode & S_IFMT) {
case S_IFDIR:
- ret = erofs_extract_dir(inode);
+ ret = erofs_extract_dir(inode, path);
break;
case S_IFREG:
- ret = erofs_extract_file(inode);
+ ret = erofs_extract_file(inode, path);
break;
case S_IFLNK:
- ret = erofs_extract_symlink(inode);
+ ret = erofs_extract_symlink(inode, path);
break;
case S_IFCHR:
case S_IFBLK:
case S_IFIFO:
case S_IFSOCK:
- ret = erofs_extract_special(inode);
+ ret = erofs_extract_special(inode, path);
break;
default:
/* TODO */
@@ -972,13 +1044,14 @@ verify:
/* record nid and old path for hardlink */
if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode))
ret = erofsfsck_hardlink_insert(inode->nid,
- fsckcfg.extract_path);
+ path);
return ret;
}
-static int erofsfsck_check_inode(erofs_nid_t pnid, erofs_nid_t nid)
+static int erofsfsck_check_inode(erofs_nid_t pnid, erofs_nid_t nid, const char *path,
+ struct erofsfsck_dirstack *dirstack)
{
- int ret, i;
+ int ret;
struct erofs_inode inode = {.sbi = &g_sbi, .nid = nid};
erofs_dbg("check inode: nid(%llu)", nid | 0ULL);
@@ -997,7 +1070,7 @@ static int erofsfsck_check_inode(erofs_nid_t pnid, erofs_nid_t nid)
goto out;
}
- ret = erofsfsck_extract_inode(&inode);
+ ret = erofsfsck_extract_inode(&inode, path);
if (ret && ret != -ECANCELED)
goto out;
@@ -1008,26 +1081,39 @@ static int erofsfsck_check_inode(erofs_nid_t pnid, erofs_nid_t nid)
}
if (S_ISDIR(inode.i_mode)) {
- struct erofs_dir_context ctx = {
- .flags = EROFS_READDIR_VALID_PNID,
- .pnid = pnid,
- .dir = &inode,
- .cb = erofsfsck_dirent_iter,
+ struct erofsfsck_dirstack ds = {
+ .nid = pnid,
+ .parent = dirstack,
+ .depth = dirstack ? dirstack->depth + 1 : 0
};
- /* XXX: support the deeper cases later */
- if (fsckcfg.dirstack.top >= ARRAY_SIZE(fsckcfg.dirstack.dirs))
- return -ENAMETOOLONG;
- for (i = 0; i < fsckcfg.dirstack.top; ++i)
- if (inode.nid == fsckcfg.dirstack.dirs[i])
- return -ELOOP;
- fsckcfg.dirstack.dirs[fsckcfg.dirstack.top++] = pnid;
- ret = erofs_iterate_dir(&ctx, true);
- --fsckcfg.dirstack.top;
+ struct erofsfsck_dir_context ctx = {
+ .ctx.flags = EROFS_READDIR_VALID_PNID,
+ .ctx.pnid = pnid,
+ .ctx.dir = &inode,
+ .ctx.cb = erofsfsck_dirent_iter,
+ .parent_path = path,
+ .dirstack = &ds
+ };
+
+ struct erofsfsck_dirstack *check_ds = dirstack;
+ while (check_ds) {
+ if (inode.nid == check_ds->nid) {
+ ret = -ELOOP;
+ goto out;
+ }
+ if (check_ds->depth >= PATH_MAX) {
+ ret = -ENAMETOOLONG;
+ goto out;
+ }
+ check_ds = check_ds->parent;
+ }
+
+ ret = erofs_iterate_dir(&ctx.ctx, true);
}
if (!ret && !erofs_is_packed_inode(&inode))
- erofsfsck_set_attributes(&inode, fsckcfg.extract_path);
+ erofsfsck_set_attributes(&inode, (char *)path);
if (ret == -ECANCELED)
ret = 0;
@@ -1043,6 +1129,7 @@ int erofsfsck_fuzz_one(int argc, char *argv[])
int main(int argc, char *argv[])
#endif
{
+
int err;
erofs_init_configure();
@@ -1120,7 +1207,8 @@ int main(int argc, char *argv[])
goto exit_hardlink;
}
- err = erofsfsck_check_inode(g_sbi.packed_nid, g_sbi.packed_nid);
+ err = erofsfsck_check_inode(g_sbi.packed_nid, g_sbi.packed_nid,
+ fsckcfg.extract_path, NULL);
if (err) {
erofs_err("failed to verify packed file");
goto exit_packedinode;
@@ -1128,6 +1216,17 @@ int main(int argc, char *argv[])
}
}
+#ifdef EROFS_MT_ENABLED
+ erofs_cond_init(&erofsfsck_mt_cond);
+
+ int workers = erofs_get_available_processors();
+ if (workers < 1)
+ workers = 1;
+
+ erofs_alloc_workqueue(&erofsfsck_wq, workers, 256, NULL, NULL);
+ erofs_alloc_workqueue(&z_erofs_mt_wq, workers, 256, NULL, NULL);
+#endif
+
{
erofs_nid_t pnid = fsckcfg.nid;
@@ -1135,17 +1234,19 @@ int main(int argc, char *argv[])
struct erofs_inode inode = { .sbi = &g_sbi, .nid = fsckcfg.nid };
if (!erofs_read_inode_from_disk(&inode) &&
- S_ISDIR(inode.i_mode)) {
- struct erofsfsck_get_parent_ctx ctx = {
+ S_ISDIR(inode.i_mode)) {
+ struct erofsfsck_dir_context ctx = {
.ctx.dir = &inode,
.ctx.cb = erofsfsck_get_parent_cb,
};
if (erofs_iterate_dir(&ctx.ctx, false) == 1)
- pnid = ctx.pnid;
+ pnid = ctx.ctx.pnid;
}
}
- err = erofsfsck_check_inode(pnid, fsckcfg.nid);
+
+ err = erofsfsck_check_inode(pnid, fsckcfg.nid, fsckcfg.extract_path, NULL);
+ erofsfsck_wait_pending_inodes();
}
if (fsckcfg.corrupted) {
@@ -1169,6 +1270,11 @@ int main(int argc, char *argv[])
}
}
+#ifdef EROFS_MT_ENABLED
+ erofs_destroy_workqueue(&erofsfsck_wq);
+ erofs_destroy_workqueue(&z_erofs_mt_wq);
+#endif
+
exit_packedinode:
erofs_packedfile_exit(&g_sbi);
exit_hardlink:
diff --git a/include/erofs/cond.h b/include/erofs/cond.h
new file mode 100644
index 0000000..90ec838
--- /dev/null
+++ b/include/erofs/cond.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0+ OR Apache-2.0 */
+#ifndef __EROFS_COND_H
+#define __EROFS_COND_H
+
+#include "lock.h"
+
+#if defined(HAVE_PTHREAD_H) && defined(EROFS_MT_ENABLED)
+#include <pthread.h>
+
+typedef pthread_cond_t erofs_cond_t;
+
+static inline void erofs_cond_init(erofs_cond_t *cond)
+{
+ pthread_cond_init(cond, NULL);
+}
+#define erofs_cond_wait pthread_cond_wait
+#define erofs_cond_signal pthread_cond_signal
+#define erofs_cond_broadcast pthread_cond_broadcast
+#define erofs_cond_destroy pthread_cond_destroy
+
+#else
+typedef struct {} erofs_cond_t;
+
+static inline void erofs_cond_init(erofs_cond_t *cond) {}
+static inline int erofs_cond_wait(erofs_cond_t *cond, erofs_mutex_t *mutex) { return 0; }
+static inline int erofs_cond_signal(erofs_cond_t *cond) { return 0; }
+static inline int erofs_cond_broadcast(erofs_cond_t *cond) { return 0; }
+static inline int erofs_cond_destroy(erofs_cond_t *cond) { return 0; }
+#endif
+
+#endif
\ No newline at end of file
diff --git a/include/erofs/internal.h b/include/erofs/internal.h
index 671880f..a3ddcfb 100644
--- a/include/erofs/internal.h
+++ b/include/erofs/internal.h
@@ -25,6 +25,8 @@ typedef unsigned short umode_t;
#ifdef HAVE_PTHREAD_H
#include <pthread.h>
#endif
+#include <erofs/lock.h>
+#include "erofs/cond.h"
#include <stdlib.h>
#include <string.h>
#include "atomic.h"
@@ -62,6 +64,7 @@ struct erofs_buf {
#define erofs_pos(sbi, nr) ((erofs_off_t)(nr) << (sbi)->blkszbits)
#define BLK_ROUND_UP(sbi, addr) \
(roundup(addr, erofs_blksiz(sbi)) >> (sbi)->blkszbits)
+#define Z_EROFS_PCLUSTER_MAX_BATCH_SIZE 32
struct erofs_buffer_head;
struct erofs_bufmgr;
@@ -442,6 +445,15 @@ struct z_erofs_paramset {
char *extraopts;
};
+struct z_erofs_decompress_task;
+
+struct z_erofs_mt_read_ctx;
+
+struct z_erofs_mt_read_ctx *z_erofs_mt_read_ctx_alloc(int outfd, bool free_out);
+int z_erofs_mt_read_ctx_wait(struct z_erofs_mt_read_ctx *ctx);
+void z_erofs_mt_read_ctx_free(struct z_erofs_mt_read_ctx *ctx);
+void z_erofs_mt_read_enqueue(struct z_erofs_mt_read_ctx *ctx);
+
int liberofs_global_init(void);
void liberofs_global_exit(void);
@@ -478,7 +490,8 @@ int erofs_read_one_data(struct erofs_inode *inode, struct erofs_map_blocks *map,
char *buffer, u64 offset, size_t len);
int z_erofs_read_one_data(struct erofs_inode *inode,
struct erofs_map_blocks *map, char *raw, char *buffer,
- erofs_off_t skip, erofs_off_t length, bool trimmed);
+ erofs_off_t skip, erofs_off_t length, bool trimmed,
+ erofs_off_t out_offset, struct z_erofs_mt_read_ctx *ctx);
void *erofs_read_metadata(struct erofs_sb_info *sbi, erofs_nid_t nid,
erofs_off_t *offset, int *lengthp);
int z_erofs_parse_cfgs(struct erofs_sb_info *sbi, struct erofs_super_block *dsb);
diff --git a/include/erofs/lock.h b/include/erofs/lock.h
index c6e3093..2e79d52 100644
--- a/include/erofs/lock.h
+++ b/include/erofs/lock.h
@@ -15,6 +15,7 @@ static inline void erofs_mutex_init(erofs_mutex_t *lock)
}
#define erofs_mutex_lock pthread_mutex_lock
#define erofs_mutex_unlock pthread_mutex_unlock
+#define erofs_mutex_destroy pthread_mutex_destroy
#define EROFS_DEFINE_MUTEX(lock) \
erofs_mutex_t lock = PTHREAD_MUTEX_INITIALIZER
@@ -29,12 +30,14 @@ static inline void erofs_init_rwsem(erofs_rwsem_t *lock)
#define erofs_down_write pthread_rwlock_wrlock
#define erofs_up_read pthread_rwlock_unlock
#define erofs_up_write pthread_rwlock_unlock
+
#else
typedef struct {} erofs_mutex_t;
static inline void erofs_mutex_init(erofs_mutex_t *lock) {}
static inline void erofs_mutex_lock(erofs_mutex_t *lock) {}
static inline void erofs_mutex_unlock(erofs_mutex_t *lock) {}
+static inline void erofs_mutex_destroy(erofs_mutex_t *lock) {}
#define EROFS_DEFINE_MUTEX(lock) \
erofs_mutex_t lock = {}
diff --git a/lib/data.c b/lib/data.c
index 6fd1389..6208d37 100644
--- a/lib/data.c
+++ b/lib/data.c
@@ -9,6 +9,121 @@
#include "erofs/trace.h"
#include "erofs/decompress.h"
#include "liberofs_fragments.h"
+#include "erofs/workqueue.h"
+#include "erofs/lock.h"
+
+struct erofs_workqueue z_erofs_mt_wq;
+
+struct z_erofs_mt_read_ctx {
+ erofs_mutex_t lock;
+ erofs_cond_t cond;
+ int pending_tasks;
+ int final_err;
+ int outfd;
+ bool free_out;
+ struct z_erofs_decompress_task *current_task;
+};
+
+struct z_erofs_mt_read_ctx *z_erofs_mt_read_ctx_alloc(int outfd, bool free_out)
+{
+ struct z_erofs_mt_read_ctx *ctx = calloc(1, sizeof(*ctx));
+ if (!ctx)
+ return NULL;
+
+ erofs_mutex_init(&ctx->lock);
+ erofs_cond_init(&ctx->cond);
+ ctx->outfd = outfd;
+ ctx->free_out = free_out;
+ return ctx;
+}
+
+int z_erofs_mt_read_ctx_wait(struct z_erofs_mt_read_ctx *ctx)
+{
+ int err;
+ if (!ctx)
+ return 0;
+
+ erofs_mutex_lock(&ctx->lock);
+ while (ctx->pending_tasks > 0)
+ erofs_cond_wait(&ctx->cond, &ctx->lock);
+ err = ctx->final_err;
+ erofs_mutex_unlock(&ctx->lock);
+
+ return err;
+}
+
+void z_erofs_mt_read_ctx_free(struct z_erofs_mt_read_ctx *ctx)
+{
+ if (!ctx)
+ return;
+
+ erofs_mutex_destroy(&ctx->lock);
+ erofs_cond_destroy(&ctx->cond);
+ free(ctx);
+}
+
+struct z_erofs_decompress_item {
+ struct z_erofs_decompress_req req;
+ char *raw_buf;
+ char *out_buf;
+ erofs_off_t out_offset;
+ unsigned int out_length;
+};
+
+struct z_erofs_decompress_task {
+ struct erofs_work work;
+ struct z_erofs_mt_read_ctx *ctx;
+ struct z_erofs_decompress_item items[Z_EROFS_PCLUSTER_MAX_BATCH_SIZE];
+ unsigned int nr_reqs;
+};
+
+static void z_erofs_decompress_worker(struct erofs_work *work, void *tlsp)
+{
+ struct z_erofs_decompress_task *task = (struct z_erofs_decompress_task *)work;
+ struct z_erofs_mt_read_ctx *ctx = task->ctx;
+ int i, ret = 0, first_err = 0;
+
+ for (i = 0; i < task->nr_reqs; ++i) {
+ struct z_erofs_decompress_item *item = &task->items[i];
+ ret = z_erofs_decompress(&item->req);
+
+ if (ret >= 0 && ctx && ctx->outfd >= 0) {
+ if (pwrite(ctx->outfd, item->out_buf,
+ item->out_length, item->out_offset) < 0)
+ ret = -errno;
+ }
+
+ if (ret < 0 && !first_err)
+ first_err = ret;
+
+ free(item->raw_buf);
+ if (ctx && ctx->free_out)
+ free(item->out_buf);
+ }
+
+ if (ctx) {
+ erofs_mutex_lock(&ctx->lock);
+ if (first_err < 0 && !ctx->final_err)
+ ctx->final_err = first_err;
+ ctx->pending_tasks--;
+ if (!ctx->pending_tasks)
+ erofs_cond_signal(&ctx->cond);
+ erofs_mutex_unlock(&ctx->lock);
+ }
+ free(task);
+}
+
+void z_erofs_mt_read_enqueue(struct z_erofs_mt_read_ctx *ctx)
+{
+ if (ctx && ctx->current_task) {
+#ifdef EROFS_MT_ENABLED
+ erofs_queue_work(&z_erofs_mt_wq, &ctx->current_task->work);
+#else
+ z_erofs_decompress_worker(&ctx->current_task->work, NULL);
+#endif
+ ctx->current_task = NULL;
+ }
+}
void *erofs_bread(struct erofs_buf *buf, erofs_off_t offset, bool need_kmap)
{
@@ -277,20 +392,28 @@ static int erofs_read_raw_data(struct erofs_inode *inode, char *buffer,
int z_erofs_read_one_data(struct erofs_inode *inode,
struct erofs_map_blocks *map, char *raw, char *buffer,
- erofs_off_t skip, erofs_off_t length, bool trimmed)
+ erofs_off_t skip, erofs_off_t length, bool trimmed,
+ erofs_off_t out_offset, struct z_erofs_mt_read_ctx *ctx)
{
struct erofs_sb_info *sbi = inode->sbi;
struct erofs_map_dev mdev;
- int ret = 0;
+ struct z_erofs_decompress_task *task;
+ struct z_erofs_decompress_item *item;
+ int ret = 0, idx, batch_limit;
if (map->m_flags & __EROFS_MAP_FRAGMENT) {
if (__erofs_unlikely(inode->nid == sbi->packed_nid)) {
- erofs_err("fragment should not exist in the packed inode %llu",
- sbi->packed_nid | 0ULL);
- return -EFSCORRUPTED;
+ ret = -EFSCORRUPTED;
+ goto err_out;
}
- return erofs_packedfile_read(sbi, buffer, length - skip,
- inode->fragmentoff + skip);
+ ret = erofs_packedfile_read(sbi, buffer, length - skip,
+ inode->fragmentoff + skip);
+
+ if (ret >= 0 && ctx && ctx->outfd >= 0) {
+ if (pwrite(ctx->outfd, buffer, length - skip, out_offset) < 0)
+ ret = -errno;
+ }
+ goto err_out;
}
/* no device id here, thus it will always succeed */
@@ -298,46 +421,77 @@ int z_erofs_read_one_data(struct erofs_inode *inode,
.m_pa = map->m_pa,
};
ret = erofs_map_dev(sbi, &mdev);
- if (ret) {
- DBG_BUGON(1);
- return ret;
- }
+ if (ret)
+ goto err_out;
ret = erofs_dev_read(sbi, mdev.m_deviceid, raw, mdev.m_pa, map->m_plen);
if (ret < 0)
- return ret;
+ goto err_out;
+
+ task = ctx->current_task;
+ if (!task) {
+ task = calloc(1, sizeof(*task));
+ task->ctx = ctx;
+ task->work.fn = z_erofs_decompress_worker;
+ ctx->current_task = task;
+
+ erofs_mutex_lock(&ctx->lock);
+ ctx->pending_tasks++;
+ erofs_mutex_unlock(&ctx->lock);
+ }
- ret = z_erofs_decompress(&(struct z_erofs_decompress_req) {
- .sbi = sbi,
- .in = raw,
- .out = buffer,
- .decodedskip = skip,
- .interlaced_offset =
- map->m_algorithmformat == Z_EROFS_COMPRESSION_INTERLACED ?
- erofs_blkoff(sbi, map->m_la) : 0,
- .inputsize = map->m_plen,
- .decodedlength = length,
- .alg = map->m_algorithmformat,
- .partial_decoding = trimmed ? true :
- !(map->m_flags & EROFS_MAP_FULL_MAPPED) ||
- (map->m_flags & EROFS_MAP_PARTIAL_REF),
- });
- if (ret < 0)
- return ret;
+ idx = task->nr_reqs++;
+ item = &task->items[idx];
+
+ item->req = (struct z_erofs_decompress_req) {
+ .sbi = sbi,
+ .in = raw,
+ .out = buffer,
+ .decodedskip = skip,
+ .interlaced_offset =
+ map->m_algorithmformat == Z_EROFS_COMPRESSION_INTERLACED ?
+ erofs_blkoff(sbi, map->m_la) : 0,
+ .inputsize = map->m_plen,
+ .decodedlength = length,
+ .alg = map->m_algorithmformat,
+ .partial_decoding = trimmed ? true :
+ !(map->m_flags & EROFS_MAP_FULL_MAPPED) ||
+ (map->m_flags & EROFS_MAP_PARTIAL_REF),
+ };
+ item->raw_buf = raw;
+ item->out_buf = buffer;
+ item->out_offset = out_offset;
+ item->out_length = length;
+
+ batch_limit = (map->m_algorithmformat == Z_EROFS_COMPRESSION_LZ4) ?
+ Z_EROFS_PCLUSTER_MAX_BATCH_SIZE : 8;
+
+ if (task->nr_reqs >= batch_limit) {
+ z_erofs_mt_read_enqueue(ctx);
+ }
return 0;
+
+err_out:
+ if (ctx && ctx->free_out)
+ free(buffer);
+ free(raw);
+ return ret;
}
static int z_erofs_read_data(struct erofs_inode *inode, char *buffer,
- erofs_off_t size, erofs_off_t offset)
+ erofs_off_t size, erofs_off_t offset)
{
erofs_off_t end, length, skip;
struct erofs_map_blocks map = {
.buf = __EROFS_BUF_INITIALIZER,
};
bool trimmed;
- unsigned int bufsize = 0;
- char *raw = NULL;
- int ret = 0;
+ int ret = 0, wait_err;
+ struct z_erofs_mt_read_ctx *ctx;
+
+ ctx = z_erofs_mt_read_ctx_alloc(-1, false);
+ if (!ctx)
+ return -ENOMEM;
end = offset + size;
while (end > offset) {
@@ -355,7 +509,6 @@ static int z_erofs_read_data(struct erofs_inode *inode, char *buffer,
length = end - map.m_la;
trimmed = true;
} else {
- DBG_BUGON(end != map.m_la + map.m_llen);
length = map.m_llen;
trimmed = false;
}
@@ -374,25 +527,26 @@ static int z_erofs_read_data(struct erofs_inode *inode, char *buffer,
continue;
}
- if (map.m_plen > bufsize) {
- char *newraw;
-
- bufsize = map.m_plen;
- newraw = realloc(raw, bufsize);
- if (!newraw) {
- ret = -ENOMEM;
- break;
- }
- raw = newraw;
+ char *raw = malloc(map.m_plen);
+ if (!raw) {
+ ret = -ENOMEM;
+ break;
}
ret = z_erofs_read_one_data(inode, &map, raw,
- buffer + end - offset, skip, length, trimmed);
+ buffer + end - offset, skip, length, trimmed, 0, ctx);
if (ret < 0)
break;
+
}
- if (raw)
- free(raw);
+ z_erofs_mt_read_enqueue(ctx);
+
+ wait_err = z_erofs_mt_read_ctx_wait(ctx);
+ if (wait_err < 0 && !ret)
+ ret = wait_err;
+
+ z_erofs_mt_read_ctx_free(ctx);
+
return ret < 0 ? ret : 0;
}
--
2.52.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] erofs-utils: fsck: add concurrent extraction and decompression
2026-07-02 8:10 [PATCH] erofs-utils: fsck: add concurrent extraction and decompression Nithurshen
@ 2026-07-02 12:54 ` Gao Xiang
2026-07-02 12:59 ` Nithurshen Karthikeyan
0 siblings, 1 reply; 4+ messages in thread
From: Gao Xiang @ 2026-07-02 12:54 UTC (permalink / raw)
To: Nithurshen, linux-erofs; +Cc: xiang, hsiangkao
On 2026/7/2 16:10, Nithurshen wrote:
> This patch introduces a multi-threaded pipeline for fsck.erofs,
> combining parallel directory traversal with background pcluster
> decompression to significantly reduce extraction time.
>
> Key architectural changes include:
>
> - Thread-Safe State: Removes the global dirstack array and
> fsckcfg.extract_path. These are replaced with per-task localized
> paths and thread-local linked lists to eliminate data races.
> - Concurrent Traversal: Refactors erofsfsck_dirent_iter to allocate
> task structures and dispatch inode processing to a background
> workqueue (z_erofs_mt_wq).
> - Asynchronous Decompression: Introduces z_erofs_mt_read_ctx to
> batch pcluster reads and decouple decompression from main I/O.
> Limits batch size dynamically (32 for LZ4, 8 for compute-heavy
> algorithms) to balance CPU cache hits and memory overhead.
> - Memory & Deadlock Safety: Implements inline backpressure during
> directory iteration. If pending inodes exceed workqueue capacity,
> execution falls back to synchronous processing to prevent
> recursive thread-pool starvation and unbounded memory growth.
> - Synchronization Primitives: Adds portable condition variable
> wrappers (erofs_cond_t) to ensure the main thread safely waits
> for all pending background inodes before exiting.
>
> Signed-off-by: Nithurshen <nithurshen.dev@gmail.com>
What's the relationship with the previous two patches?
Thanks,
Gao Xiang
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] erofs-utils: fsck: add concurrent extraction and decompression
2026-07-02 12:54 ` Gao Xiang
@ 2026-07-02 12:59 ` Nithurshen Karthikeyan
2026-07-02 18:20 ` Gao Xiang
0 siblings, 1 reply; 4+ messages in thread
From: Nithurshen Karthikeyan @ 2026-07-02 12:59 UTC (permalink / raw)
To: Gao Xiang; +Cc: linux-erofs, xiang, hsiangkao
[-- Attachment #1: Type: text/plain, Size: 1723 bytes --]
On Thu, 2 Jul, 2026, 18:24 Gao Xiang, <hsiangkao@linux.alibaba.com> wrote:
>
>
> On 2026/7/2 16:10, Nithurshen wrote:
> > This patch introduces a multi-threaded pipeline for fsck.erofs,
> > combining parallel directory traversal with background pcluster
> > decompression to significantly reduce extraction time.
> >
> > Key architectural changes include:
> >
> > - Thread-Safe State: Removes the global dirstack array and
> > fsckcfg.extract_path. These are replaced with per-task localized
> > paths and thread-local linked lists to eliminate data races.
> > - Concurrent Traversal: Refactors erofsfsck_dirent_iter to allocate
> > task structures and dispatch inode processing to a background
> > workqueue (z_erofs_mt_wq).
> > - Asynchronous Decompression: Introduces z_erofs_mt_read_ctx to
> > batch pcluster reads and decouple decompression from main I/O.
> > Limits batch size dynamically (32 for LZ4, 8 for compute-heavy
> > algorithms) to balance CPU cache hits and memory overhead.
> > - Memory & Deadlock Safety: Implements inline backpressure during
> > directory iteration. If pending inodes exceed workqueue capacity,
> > execution falls back to synchronous processing to prevent
> > recursive thread-pool starvation and unbounded memory growth.
> > - Synchronization Primitives: Adds portable condition variable
> > wrappers (erofs_cond_t) to ensure the main thread safely waits
> > for all pending background inodes before exiting.
> >
> > Signed-off-by: Nithurshen <nithurshen.dev@gmail.com>
>
> What's the relationship with the previous two patches?
>
I made then into one atomic patch, since you wanted them merged at once.
Thanks,
Nithurshen
Thanks,
> Gao Xiang
>
[-- Attachment #2: Type: text/html, Size: 2651 bytes --]
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] erofs-utils: fsck: add concurrent extraction and decompression
2026-07-02 12:59 ` Nithurshen Karthikeyan
@ 2026-07-02 18:20 ` Gao Xiang
0 siblings, 0 replies; 4+ messages in thread
From: Gao Xiang @ 2026-07-02 18:20 UTC (permalink / raw)
To: Nithurshen Karthikeyan; +Cc: linux-erofs, xiang, hsiangkao
On 2026/7/2 20:59, Nithurshen Karthikeyan wrote:
> On Thu, 2 Jul, 2026, 18:24 Gao Xiang, <hsiangkao@linux.alibaba.com> wrote:
>
>>
>>
>> On 2026/7/2 16:10, Nithurshen wrote:
>>> This patch introduces a multi-threaded pipeline for fsck.erofs,
>>> combining parallel directory traversal with background pcluster
>>> decompression to significantly reduce extraction time.
>>>
>>> Key architectural changes include:
>>>
>>> - Thread-Safe State: Removes the global dirstack array and
>>> fsckcfg.extract_path. These are replaced with per-task localized
>>> paths and thread-local linked lists to eliminate data races.
>>> - Concurrent Traversal: Refactors erofsfsck_dirent_iter to allocate
>>> task structures and dispatch inode processing to a background
>>> workqueue (z_erofs_mt_wq).
>>> - Asynchronous Decompression: Introduces z_erofs_mt_read_ctx to
>>> batch pcluster reads and decouple decompression from main I/O.
>>> Limits batch size dynamically (32 for LZ4, 8 for compute-heavy
>>> algorithms) to balance CPU cache hits and memory overhead.
>>> - Memory & Deadlock Safety: Implements inline backpressure during
>>> directory iteration. If pending inodes exceed workqueue capacity,
>>> execution falls back to synchronous processing to prevent
>>> recursive thread-pool starvation and unbounded memory growth.
>>> - Synchronization Primitives: Adds portable condition variable
>>> wrappers (erofs_cond_t) to ensure the main thread safely waits
>>> for all pending background inodes before exiting.
>>>
>>> Signed-off-by: Nithurshen <nithurshen.dev@gmail.com>
>>
>> What's the relationship with the previous two patches?
>>
>
> I made then into one atomic patch, since you wanted them merged at once.
Nope, I didn't want that, I suggested you benchmark each patch.
But it doesn't mean the patches should be merged.
The merge meant merging commits to erofs-utils.
Thanks,
Gao Xiang
>
> Thanks,
> Nithurshen
>
> Thanks,
>> Gao Xiang
>>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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-- links below jump to the message on this page --
2026-07-02 8:10 [PATCH] erofs-utils: fsck: add concurrent extraction and decompression Nithurshen
2026-07-02 12:54 ` Gao Xiang
2026-07-02 12:59 ` Nithurshen Karthikeyan
2026-07-02 18:20 ` Gao Xiang
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