Merge tag 'erofs-for-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang...
authorLinus Torvalds <torvalds@linux-foundation.org>
Mon, 30 Mar 2020 19:49:33 +0000 (12:49 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Mon, 30 Mar 2020 19:49:33 +0000 (12:49 -0700)
Pull erofs updates from Gao Xiang:
 "Updates with a XArray adaptation, several fixes for shrinker and
  corrupted images are ready for this cycle.

  All commits have been stress tested with no noticeable smoke out and
  have been in linux-next as well.

  Summary:

   - Convert radix tree usage to XArray

   - Fix shrink scan count on multiple filesystem instances

   - Better handling for specific corrupted images

   - Update my email address in MAINTAINERS"

* tag 'erofs-for-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  MAINTAINERS: erofs: update my email address
  erofs: handle corrupted images whose decompressed size less than it'd be
  erofs: use LZ4_decompress_safe() for full decoding
  erofs: correct the remaining shrink objects
  erofs: convert workstn to XArray

MAINTAINERS
fs/erofs/decompressor.c
fs/erofs/internal.h
fs/erofs/super.c
fs/erofs/utils.c
fs/erofs/zdata.c

index 953478c..bbec693 100644 (file)
@@ -6248,7 +6248,7 @@ F:        drivers/video/fbdev/s1d13xxxfb.c
 F:     include/video/s1d13xxxfb.h
 
 EROFS FILE SYSTEM
-M:     Gao Xiang <gaoxiang25@huawei.com>
+M:     Gao Xiang <xiang@kernel.org>
 M:     Chao Yu <yuchao0@huawei.com>
 L:     linux-erofs@lists.ozlabs.org
 S:     Maintained
index 5779a15..5d2d819 100644 (file)
@@ -157,17 +157,27 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
                }
        }
 
-       ret = LZ4_decompress_safe_partial(src + inputmargin, out,
-                                         inlen, rq->outputsize,
-                                         rq->outputsize);
-       if (ret < 0) {
-               erofs_err(rq->sb, "failed to decompress, in[%u, %u] out[%u]",
-                         inlen, inputmargin, rq->outputsize);
+       /* legacy format could compress extra data in a pcluster. */
+       if (rq->partial_decoding || !support_0padding)
+               ret = LZ4_decompress_safe_partial(src + inputmargin, out,
+                                                 inlen, rq->outputsize,
+                                                 rq->outputsize);
+       else
+               ret = LZ4_decompress_safe(src + inputmargin, out,
+                                         inlen, rq->outputsize);
+
+       if (ret != rq->outputsize) {
+               erofs_err(rq->sb, "failed to decompress %d in[%u, %u] out[%u]",
+                         ret, inlen, inputmargin, rq->outputsize);
+
                WARN_ON(1);
                print_hex_dump(KERN_DEBUG, "[ in]: ", DUMP_PREFIX_OFFSET,
                               16, 1, src + inputmargin, inlen, true);
                print_hex_dump(KERN_DEBUG, "[out]: ", DUMP_PREFIX_OFFSET,
                               16, 1, out, rq->outputsize, true);
+
+               if (ret >= 0)
+                       memset(out + ret, 0, rq->outputsize - ret);
                ret = -EIO;
        }
 
index c4c6dcd..5eead7f 100644 (file)
@@ -52,8 +52,8 @@ struct erofs_sb_info {
        struct list_head list;
        struct mutex umount_mutex;
 
-       /* the dedicated workstation for compression */
-       struct radix_tree_root workstn_tree;
+       /* managed XArray arranged in physical block number */
+       struct xarray managed_pslots;
 
        /* threshold for decompression synchronously */
        unsigned int max_sync_decompress_pages;
@@ -402,8 +402,8 @@ static inline void *erofs_get_pcpubuf(unsigned int pagenr)
 int erofs_workgroup_put(struct erofs_workgroup *grp);
 struct erofs_workgroup *erofs_find_workgroup(struct super_block *sb,
                                             pgoff_t index);
-int erofs_register_workgroup(struct super_block *sb,
-                            struct erofs_workgroup *grp);
+struct erofs_workgroup *erofs_insert_workgroup(struct super_block *sb,
+                                              struct erofs_workgroup *grp);
 void erofs_workgroup_free_rcu(struct erofs_workgroup *grp);
 void erofs_shrinker_register(struct super_block *sb);
 void erofs_shrinker_unregister(struct super_block *sb);
index 057e6d7..b514c67 100644 (file)
@@ -425,7 +425,7 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
                sb->s_flags &= ~SB_POSIXACL;
 
 #ifdef CONFIG_EROFS_FS_ZIP
-       INIT_RADIX_TREE(&sbi->workstn_tree, GFP_ATOMIC);
+       xa_init(&sbi->managed_pslots);
 #endif
 
        /* get the root inode */
index fddc505..52d0be1 100644 (file)
@@ -37,9 +37,6 @@ void *erofs_get_pcpubuf(unsigned int pagenr)
 /* global shrink count (for all mounted EROFS instances) */
 static atomic_long_t erofs_global_shrink_cnt;
 
-#define __erofs_workgroup_get(grp)     atomic_inc(&(grp)->refcount)
-#define __erofs_workgroup_put(grp)     atomic_dec(&(grp)->refcount)
-
 static int erofs_workgroup_get(struct erofs_workgroup *grp)
 {
        int o;
@@ -66,7 +63,7 @@ struct erofs_workgroup *erofs_find_workgroup(struct super_block *sb,
 
 repeat:
        rcu_read_lock();
-       grp = radix_tree_lookup(&sbi->workstn_tree, index);
+       grp = xa_load(&sbi->managed_pslots, index);
        if (grp) {
                if (erofs_workgroup_get(grp)) {
                        /* prefer to relax rcu read side */
@@ -80,43 +77,37 @@ repeat:
        return grp;
 }
 
-int erofs_register_workgroup(struct super_block *sb,
-                            struct erofs_workgroup *grp)
+struct erofs_workgroup *erofs_insert_workgroup(struct super_block *sb,
+                                              struct erofs_workgroup *grp)
 {
-       struct erofs_sb_info *sbi;
-       int err;
-
-       /* grp shouldn't be broken or used before */
-       if (atomic_read(&grp->refcount) != 1) {
-               DBG_BUGON(1);
-               return -EINVAL;
-       }
-
-       err = radix_tree_preload(GFP_NOFS);
-       if (err)
-               return err;
-
-       sbi = EROFS_SB(sb);
-       xa_lock(&sbi->workstn_tree);
+       struct erofs_sb_info *const sbi = EROFS_SB(sb);
+       struct erofs_workgroup *pre;
 
        /*
-        * Bump up reference count before making this workgroup
-        * visible to other users in order to avoid potential UAF
-        * without serialized by workstn_lock.
+        * Bump up a reference count before making this visible
+        * to others for the XArray in order to avoid potential
+        * UAF without serialized by xa_lock.
         */
-       __erofs_workgroup_get(grp);
-
-       err = radix_tree_insert(&sbi->workstn_tree, grp->index, grp);
-       if (err)
-               /*
-                * it's safe to decrease since the workgroup isn't visible
-                * and refcount >= 2 (cannot be freezed).
-                */
-               __erofs_workgroup_put(grp);
+       atomic_inc(&grp->refcount);
 
-       xa_unlock(&sbi->workstn_tree);
-       radix_tree_preload_end();
-       return err;
+repeat:
+       xa_lock(&sbi->managed_pslots);
+       pre = __xa_cmpxchg(&sbi->managed_pslots, grp->index,
+                          NULL, grp, GFP_NOFS);
+       if (pre) {
+               if (xa_is_err(pre)) {
+                       pre = ERR_PTR(xa_err(pre));
+               } else if (erofs_workgroup_get(pre)) {
+                       /* try to legitimize the current in-tree one */
+                       xa_unlock(&sbi->managed_pslots);
+                       cond_resched();
+                       goto repeat;
+               }
+               atomic_dec(&grp->refcount);
+               grp = pre;
+       }
+       xa_unlock(&sbi->managed_pslots);
+       return grp;
 }
 
 static void  __erofs_workgroup_free(struct erofs_workgroup *grp)
@@ -155,7 +146,7 @@ static bool erofs_try_to_release_workgroup(struct erofs_sb_info *sbi,
 
        /*
         * Note that all cached pages should be unattached
-        * before deleted from the radix tree. Otherwise some
+        * before deleted from the XArray. Otherwise some
         * cached pages could be still attached to the orphan
         * old workgroup when the new one is available in the tree.
         */
@@ -169,7 +160,7 @@ static bool erofs_try_to_release_workgroup(struct erofs_sb_info *sbi,
         * however in order to avoid some race conditions, add a
         * DBG_BUGON to observe this in advance.
         */
-       DBG_BUGON(radix_tree_delete(&sbi->workstn_tree, grp->index) != grp);
+       DBG_BUGON(xa_erase(&sbi->managed_pslots, grp->index) != grp);
 
        /*
         * If managed cache is on, last refcount should indicate
@@ -182,22 +173,11 @@ static bool erofs_try_to_release_workgroup(struct erofs_sb_info *sbi,
 static unsigned long erofs_shrink_workstation(struct erofs_sb_info *sbi,
                                              unsigned long nr_shrink)
 {
-       pgoff_t first_index = 0;
-       void *batch[PAGEVEC_SIZE];
+       struct erofs_workgroup *grp;
        unsigned int freed = 0;
+       unsigned long index;
 
-       int i, found;
-repeat:
-       xa_lock(&sbi->workstn_tree);
-
-       found = radix_tree_gang_lookup(&sbi->workstn_tree,
-                                      batch, first_index, PAGEVEC_SIZE);
-
-       for (i = 0; i < found; ++i) {
-               struct erofs_workgroup *grp = batch[i];
-
-               first_index = grp->index + 1;
-
+       xa_for_each(&sbi->managed_pslots, index, grp) {
                /* try to shrink each valid workgroup */
                if (!erofs_try_to_release_workgroup(sbi, grp))
                        continue;
@@ -206,10 +186,6 @@ repeat:
                if (!--nr_shrink)
                        break;
        }
-       xa_unlock(&sbi->workstn_tree);
-
-       if (i && nr_shrink)
-               goto repeat;
        return freed;
 }
 
@@ -286,7 +262,7 @@ static unsigned long erofs_shrink_scan(struct shrinker *shrink,
                spin_unlock(&erofs_sb_list_lock);
                sbi->shrinker_run_no = run_no;
 
-               freed += erofs_shrink_workstation(sbi, nr);
+               freed += erofs_shrink_workstation(sbi, nr - freed);
 
                spin_lock(&erofs_sb_list_lock);
                /* Get the next list element before we move this one */
index 80e47f0..c4b6c9a 100644 (file)
@@ -67,16 +67,6 @@ static void z_erofs_pcluster_init_once(void *ptr)
                pcl->compressed_pages[i] = NULL;
 }
 
-static void z_erofs_pcluster_init_always(struct z_erofs_pcluster *pcl)
-{
-       struct z_erofs_collection *cl = z_erofs_primarycollection(pcl);
-
-       atomic_set(&pcl->obj.refcount, 1);
-
-       DBG_BUGON(cl->nr_pages);
-       DBG_BUGON(cl->vcnt);
-}
-
 int __init z_erofs_init_zip_subsystem(void)
 {
        pcluster_cachep = kmem_cache_create("erofs_compress",
@@ -341,26 +331,19 @@ static int z_erofs_lookup_collection(struct z_erofs_collector *clt,
                                     struct inode *inode,
                                     struct erofs_map_blocks *map)
 {
-       struct erofs_workgroup *grp;
-       struct z_erofs_pcluster *pcl;
+       struct z_erofs_pcluster *pcl = clt->pcl;
        struct z_erofs_collection *cl;
        unsigned int length;
 
-       grp = erofs_find_workgroup(inode->i_sb, map->m_pa >> PAGE_SHIFT);
-       if (!grp)
-               return -ENOENT;
-
-       pcl = container_of(grp, struct z_erofs_pcluster, obj);
+       /* to avoid unexpected loop formed by corrupted images */
        if (clt->owned_head == &pcl->next || pcl == clt->tailpcl) {
                DBG_BUGON(1);
-               erofs_workgroup_put(grp);
                return -EFSCORRUPTED;
        }
 
        cl = z_erofs_primarycollection(pcl);
        if (cl->pageofs != (map->m_la & ~PAGE_MASK)) {
                DBG_BUGON(1);
-               erofs_workgroup_put(grp);
                return -EFSCORRUPTED;
        }
 
@@ -368,7 +351,6 @@ static int z_erofs_lookup_collection(struct z_erofs_collector *clt,
        if (length & Z_EROFS_PCLUSTER_FULL_LENGTH) {
                if ((map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT) > length) {
                        DBG_BUGON(1);
-                       erofs_workgroup_put(grp);
                        return -EFSCORRUPTED;
                }
        } else {
@@ -391,7 +373,6 @@ static int z_erofs_lookup_collection(struct z_erofs_collector *clt,
        /* clean tailpcl if the current owned_head is Z_EROFS_PCLUSTER_TAIL */
        if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL)
                clt->tailpcl = NULL;
-       clt->pcl = pcl;
        clt->cl = cl;
        return 0;
 }
@@ -402,6 +383,7 @@ static int z_erofs_register_collection(struct z_erofs_collector *clt,
 {
        struct z_erofs_pcluster *pcl;
        struct z_erofs_collection *cl;
+       struct erofs_workgroup *grp;
        int err;
 
        /* no available workgroup, let's allocate one */
@@ -409,7 +391,7 @@ static int z_erofs_register_collection(struct z_erofs_collector *clt,
        if (!pcl)
                return -ENOMEM;
 
-       z_erofs_pcluster_init_always(pcl);
+       atomic_set(&pcl->obj.refcount, 1);
        pcl->obj.index = map->m_pa >> PAGE_SHIFT;
 
        pcl->length = (map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT) |
@@ -429,19 +411,29 @@ static int z_erofs_register_collection(struct z_erofs_collector *clt,
        clt->mode = COLLECT_PRIMARY_FOLLOWED;
 
        cl = z_erofs_primarycollection(pcl);
+
+       /* must be cleaned before freeing to slab */
+       DBG_BUGON(cl->nr_pages);
+       DBG_BUGON(cl->vcnt);
+
        cl->pageofs = map->m_la & ~PAGE_MASK;
 
        /*
         * lock all primary followed works before visible to others
         * and mutex_trylock *never* fails for a new pcluster.
         */
-       mutex_trylock(&cl->lock);
+       DBG_BUGON(!mutex_trylock(&cl->lock));
 
-       err = erofs_register_workgroup(inode->i_sb, &pcl->obj);
-       if (err) {
-               mutex_unlock(&cl->lock);
-               kmem_cache_free(pcluster_cachep, pcl);
-               return -EAGAIN;
+       grp = erofs_insert_workgroup(inode->i_sb, &pcl->obj);
+       if (IS_ERR(grp)) {
+               err = PTR_ERR(grp);
+               goto err_out;
+       }
+
+       if (grp != &pcl->obj) {
+               clt->pcl = container_of(grp, struct z_erofs_pcluster, obj);
+               err = -EEXIST;
+               goto err_out;
        }
        /* used to check tail merging loop due to corrupted images */
        if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL)
@@ -450,12 +442,18 @@ static int z_erofs_register_collection(struct z_erofs_collector *clt,
        clt->pcl = pcl;
        clt->cl = cl;
        return 0;
+
+err_out:
+       mutex_unlock(&cl->lock);
+       kmem_cache_free(pcluster_cachep, pcl);
+       return err;
 }
 
 static int z_erofs_collector_begin(struct z_erofs_collector *clt,
                                   struct inode *inode,
                                   struct erofs_map_blocks *map)
 {
+       struct erofs_workgroup *grp;
        int ret;
 
        DBG_BUGON(clt->cl);
@@ -469,21 +467,25 @@ static int z_erofs_collector_begin(struct z_erofs_collector *clt,
                return -EINVAL;
        }
 
-repeat:
-       ret = z_erofs_lookup_collection(clt, inode, map);
-       if (ret == -ENOENT) {
+       grp = erofs_find_workgroup(inode->i_sb, map->m_pa >> PAGE_SHIFT);
+       if (grp) {
+               clt->pcl = container_of(grp, struct z_erofs_pcluster, obj);
+       } else {
                ret = z_erofs_register_collection(clt, inode, map);
 
-               /* someone registered at the same time, give another try */
-               if (ret == -EAGAIN) {
-                       cond_resched();
-                       goto repeat;
-               }
+               if (!ret)
+                       goto out;
+               if (ret != -EEXIST)
+                       return ret;
        }
 
-       if (ret)
+       ret = z_erofs_lookup_collection(clt, inode, map);
+       if (ret) {
+               erofs_workgroup_put(&clt->pcl->obj);
                return ret;
+       }
 
+out:
        z_erofs_pagevec_ctor_init(&clt->vector, Z_EROFS_NR_INLINE_PAGEVECS,
                                  clt->cl->pagevec, clt->cl->vcnt);