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authorVivek Goyal <vgoyal@redhat.com>2019-03-06 16:51:40 -0500
committerMiklos Szeredi <mszeredi@redhat.com>2019-09-12 08:59:41 -0400
commit0cd1eb9a4160a96e0ec9b93b2e7b489f449bf22d (patch)
tree54ff7b7366dafb376d6a94bed28a86358c6b2023
parentae3aad77f46fbba56eff7141b2fc49870b60827e (diff)
fuse: separate fuse device allocation and installation in fuse_conn
As of now fuse_dev_alloc() both allocates a fuse device and installs it in fuse_conn list. fuse_dev_alloc() can fail if fuse_device allocation fails. virtio-fs needs to initialize multiple fuse devices (one per virtio queue). It initializes one fuse device as part of call to fuse_fill_super_common() and rest of the devices are allocated and installed after that. But, we can't afford to fail after calling fuse_fill_super_common() as we don't have a way to undo all the actions done by fuse_fill_super_common(). So to avoid failures after the call to fuse_fill_super_common(), pre-allocate all fuse devices early and install them into fuse connection later. This patch provides two separate helpers for fuse device allocation and fuse device installation in fuse_conn. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
-rw-r--r--fs/fuse/cuse.c2
-rw-r--r--fs/fuse/dev.c2
-rw-r--r--fs/fuse/fuse_i.h4
-rw-r--r--fs/fuse/inode.c25
4 files changed, 26 insertions, 7 deletions
diff --git a/fs/fuse/cuse.c b/fs/fuse/cuse.c
index 6a0de0ce4403..45762bb7a934 100644
--- a/fs/fuse/cuse.c
+++ b/fs/fuse/cuse.c
@@ -508,7 +508,7 @@ static int cuse_channel_open(struct inode *inode, struct file *file)
508 */ 508 */
509 fuse_conn_init(&cc->fc, file->f_cred->user_ns, &fuse_dev_fiq_ops, NULL); 509 fuse_conn_init(&cc->fc, file->f_cred->user_ns, &fuse_dev_fiq_ops, NULL);
510 510
511 fud = fuse_dev_alloc(&cc->fc); 511 fud = fuse_dev_alloc_install(&cc->fc);
512 if (!fud) { 512 if (!fud) {
513 kfree(cc); 513 kfree(cc);
514 return -ENOMEM; 514 return -ENOMEM;
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 358a01435058..b2e18861c59c 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -2203,7 +2203,7 @@ static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2203 if (new->private_data) 2203 if (new->private_data)
2204 return -EINVAL; 2204 return -EINVAL;
2205 2205
2206 fud = fuse_dev_alloc(fc); 2206 fud = fuse_dev_alloc_install(fc);
2207 if (!fud) 2207 if (!fud)
2208 return -ENOMEM; 2208 return -ENOMEM;
2209 2209
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 8c13865955d4..242d47752e78 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -929,7 +929,9 @@ void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns,
929 */ 929 */
930void fuse_conn_put(struct fuse_conn *fc); 930void fuse_conn_put(struct fuse_conn *fc);
931 931
932struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc); 932struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc);
933struct fuse_dev *fuse_dev_alloc(void);
934void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc);
933void fuse_dev_free(struct fuse_dev *fud); 935void fuse_dev_free(struct fuse_dev *fud);
934void fuse_send_init(struct fuse_conn *fc); 936void fuse_send_init(struct fuse_conn *fc);
935 937
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 734fdd597c3e..6a0f31faaeaa 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -1045,7 +1045,7 @@ static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
1045 return 0; 1045 return 0;
1046} 1046}
1047 1047
1048struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc) 1048struct fuse_dev *fuse_dev_alloc(void)
1049{ 1049{
1050 struct fuse_dev *fud; 1050 struct fuse_dev *fud;
1051 struct list_head *pq; 1051 struct list_head *pq;
@@ -1061,16 +1061,33 @@ struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc)
1061 } 1061 }
1062 1062
1063 fud->pq.processing = pq; 1063 fud->pq.processing = pq;
1064 fud->fc = fuse_conn_get(fc);
1065 fuse_pqueue_init(&fud->pq); 1064 fuse_pqueue_init(&fud->pq);
1066 1065
1066 return fud;
1067}
1068EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1069
1070void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc)
1071{
1072 fud->fc = fuse_conn_get(fc);
1067 spin_lock(&fc->lock); 1073 spin_lock(&fc->lock);
1068 list_add_tail(&fud->entry, &fc->devices); 1074 list_add_tail(&fud->entry, &fc->devices);
1069 spin_unlock(&fc->lock); 1075 spin_unlock(&fc->lock);
1076}
1077EXPORT_SYMBOL_GPL(fuse_dev_install);
1070 1078
1079struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc)
1080{
1081 struct fuse_dev *fud;
1082
1083 fud = fuse_dev_alloc();
1084 if (!fud)
1085 return NULL;
1086
1087 fuse_dev_install(fud, fc);
1071 return fud; 1088 return fud;
1072} 1089}
1073EXPORT_SYMBOL_GPL(fuse_dev_alloc); 1090EXPORT_SYMBOL_GPL(fuse_dev_alloc_install);
1074 1091
1075void fuse_dev_free(struct fuse_dev *fud) 1092void fuse_dev_free(struct fuse_dev *fud)
1076{ 1093{
@@ -1132,7 +1149,7 @@ int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
1132 if (sb->s_user_ns != &init_user_ns) 1149 if (sb->s_user_ns != &init_user_ns)
1133 sb->s_xattr = fuse_no_acl_xattr_handlers; 1150 sb->s_xattr = fuse_no_acl_xattr_handlers;
1134 1151
1135 fud = fuse_dev_alloc(fc); 1152 fud = fuse_dev_alloc_install(fc);
1136 if (!fud) 1153 if (!fud)
1137 goto err; 1154 goto err;
1138 1155