From 55914f968d907ed747774da15285b42653afda61 Mon Sep 17 00:00:00 2001 From: Soumya Koduri Date: Mon, 6 Apr 2020 12:36:44 +0530 Subject: gfapi: Suspend synctasks instead of blocking them There are certain conditions which blocks the current execution thread (like waiting on mutex lock or condition variable or I/O response). In such cases, if it is a synctask thread, we should suspend the task instead of blocking it (like done in SYNCOP using synctask_yield) This is to avoid deadlock like the one mentioned below - 1) synctaskA sets fs->migration_in_progress to 1 and does I/O (LOOKUP) 2) Other synctask threads wait for fs->migration_in_progress to be reset to 0 by synctaskA and hence blocked 3) but synctaskA cannot resume as all synctask threads are blocked on (2). Note: this same approach is already used by few other components like syncbarrier etc. Change-Id: If90f870d663bb242c702a5b86ac52eeda67c6f0d Fixes: #1146 Signed-off-by: Soumya Koduri --- api/src/glfs-resolve.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'api/src/glfs-resolve.c') diff --git a/api/src/glfs-resolve.c b/api/src/glfs-resolve.c index 4b6f76961ee..ebc5282205f 100644 --- a/api/src/glfs-resolve.c +++ b/api/src/glfs-resolve.c @@ -65,6 +65,9 @@ __glfs_first_lookup(struct glfs *fs, xlator_t *subvol) fs->migration_in_progress = 0; pthread_cond_broadcast(&fs->cond); + /* wake up other waiting tasks */ + __GLFS_SYNCTASK_WAKE(fs); + return ret; } @@ -153,6 +156,9 @@ __glfs_refresh_inode(struct glfs *fs, xlator_t *subvol, inode_t *inode, fs->migration_in_progress = 0; pthread_cond_broadcast(&fs->cond); + /* wake up other waiting tasks */ + __GLFS_SYNCTASK_WAKE(fs); + return newinode; } @@ -830,6 +836,9 @@ __glfs_migrate_fd(struct glfs *fs, xlator_t *newsubvol, struct glfs_fd *glfd) fs->migration_in_progress = 0; pthread_cond_broadcast(&fs->cond); + /* wake up other waiting tasks */ + __GLFS_SYNCTASK_WAKE(fs); + return newfd; } -- cgit