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authorYan, Zheng <zyan@redhat.com>2017-12-15 11:15:36 +0800
committerIlya Dryomov <idryomov@gmail.com>2018-01-29 18:36:08 +0100
commit5d988308283ecf062fa88f20ae05c52cce0bcdca (patch)
treefdc84f449e10eab2f74123d38fc0f3dcf26e5b54 /fs/ceph/super.h
parent5495c2d04f85da09512f5f346ed24dc0261d905d (diff)
downloadlinux-5d988308283ecf062fa88f20ae05c52cce0bcdca.tar.bz2
ceph: track read contexts in ceph_file_info
Previously ceph_read_iter() uses current->journal to pass context info to ceph_readpages(), so that ceph_readpages() can distinguish read(2) from readahead(2)/fadvise(2)/madvise(2). The problem is that page fault can happen when copying data to userspace memory. Page fault may call other filesystem's page_mkwrite() if the userspace memory is mapped to a file. The later filesystem may also want to use current->journal. The fix is define a on-stack data structure in ceph_read_iter(), add it to context list in ceph_file_info. ceph_readpages() searches the list, find if there is a context belongs to current thread. Signed-off-by: "Yan, Zheng" <zyan@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'fs/ceph/super.h')
-rw-r--r--fs/ceph/super.h46
1 files changed, 46 insertions, 0 deletions
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 75701c199b2b..601100da738f 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -669,6 +669,9 @@ struct ceph_file_info {
short fmode; /* initialized on open */
short flags; /* CEPH_F_* */
+ spinlock_t rw_contexts_lock;
+ struct list_head rw_contexts;
+
/* readdir: position within the dir */
u32 frag;
struct ceph_mds_request *last_readdir;
@@ -685,6 +688,49 @@ struct ceph_file_info {
int dir_info_len;
};
+struct ceph_rw_context {
+ struct list_head list;
+ struct task_struct *thread;
+ int caps;
+};
+
+#define CEPH_DEFINE_RW_CONTEXT(_name, _caps) \
+ struct ceph_rw_context _name = { \
+ .thread = current, \
+ .caps = _caps, \
+ }
+
+static inline void ceph_add_rw_context(struct ceph_file_info *cf,
+ struct ceph_rw_context *ctx)
+{
+ spin_lock(&cf->rw_contexts_lock);
+ list_add(&ctx->list, &cf->rw_contexts);
+ spin_unlock(&cf->rw_contexts_lock);
+}
+
+static inline void ceph_del_rw_context(struct ceph_file_info *cf,
+ struct ceph_rw_context *ctx)
+{
+ spin_lock(&cf->rw_contexts_lock);
+ list_del(&ctx->list);
+ spin_unlock(&cf->rw_contexts_lock);
+}
+
+static inline struct ceph_rw_context*
+ceph_find_rw_context(struct ceph_file_info *cf)
+{
+ struct ceph_rw_context *ctx, *found = NULL;
+ spin_lock(&cf->rw_contexts_lock);
+ list_for_each_entry(ctx, &cf->rw_contexts, list) {
+ if (ctx->thread == current) {
+ found = ctx;
+ break;
+ }
+ }
+ spin_unlock(&cf->rw_contexts_lock);
+ return found;
+}
+
struct ceph_readdir_cache_control {
struct page *page;
struct dentry **dentries;