LU-15340 llite: Delay dput in ll_dirty_page_discard_warn

[fs/lustre-release.git] / lustre / llite / llite_lib.c

diff --git a/lustre/llite/llite_lib.c b/lustre/llite/llite_lib.c
index 21bac82..88d193d 100644 (file)
--- a/lustre/llite/llite_lib.c
+++ b/lustre/llite/llite_lib.c
@@ -3447,6 +3447,23 @@ int ll_get_obd_name(struct inode *inode, unsigned int cmd, unsigned long arg)
        RETURN(0);
 }
 
+struct dname_buf {
+       struct work_struct db_work;
+       struct dentry *db_dentry;
+       /* Let's hope the path is not too long, 32 bytes for the work struct
+        * on my kernel
+        */
+       char buf[PAGE_SIZE - sizeof(struct work_struct) - sizeof(void *)];
+};
+
+static void ll_dput_later(struct work_struct *work)
+{
+       struct dname_buf *db = container_of(work, struct dname_buf, db_work);
+
+       dput(db->db_dentry);
+       free_page((unsigned long)db);
+}
+
 static char* ll_d_path(struct dentry *dentry, char *buf, int bufsize)
 {
        char *path = NULL;
@@ -3461,33 +3478,43 @@ static char* ll_d_path(struct dentry *dentry, char *buf, int bufsize)
        return path;
 }
 
-void ll_dirty_page_discard_warn(struct page *page, int ioret)
+void ll_dirty_page_discard_warn(struct inode *inode, int ioret)
 {
-       char *buf, *path = NULL;
+       struct dname_buf *db;
+       char  *path = NULL;
        struct dentry *dentry = NULL;
-       struct inode *inode = page->mapping->host;
 
        /* this can be called inside spin lock so use GFP_ATOMIC. */
-       buf = (char *)__get_free_page(GFP_ATOMIC);
-       if (buf != NULL) {
-               dentry = d_find_alias(page->mapping->host);
+       db = (struct dname_buf *)__get_free_page(GFP_ATOMIC);
+       if (db != NULL) {
+
+               dentry = d_find_alias(inode);
                if (dentry != NULL)
-                       path = ll_d_path(dentry, buf, PAGE_SIZE);
+                       path = ll_d_path(dentry, db->buf, sizeof(db->buf));
        }
 
        /* The below message is checked in recovery-small.sh test_24b */
        CDEBUG(D_WARNING,
               "%s: dirty page discard: %s/fid: "DFID"/%s may get corrupted "
               "(rc %d)\n", ll_i2sbi(inode)->ll_fsname,
-              s2lsi(page->mapping->host->i_sb)->lsi_lmd->lmd_dev,
+              s2lsi(inode->i_sb)->lsi_lmd->lmd_dev,
               PFID(ll_inode2fid(inode)),
               (path && !IS_ERR(path)) ? path : "", ioret);
 
-       if (dentry != NULL)
-               dput(dentry);
-
-       if (buf != NULL)
-               free_page((unsigned long)buf);
+       if (dentry != NULL) {
+               /* We cannot dput here since if we happen to be the last holder
+                * then we can end up waiting for page evictions that
+                * in turn wait for RPCs that need this instance of ptlrpcd
+                * (callng brw_interpret->*page_completion*->vmpage_error->here)
+                * LU-15340
+                */
+               INIT_WORK(&db->db_work, ll_dput_later);
+               db->db_dentry = dentry;
+               schedule_work(&db->db_work);
+       } else {
+               if (db != NULL)
+                       free_page((unsigned long)db);
+       }
 }
 
 ssize_t ll_copy_user_md(const struct lov_user_md __user *md,