diff options
Diffstat (limited to 'src/filesys/filesys.c')
| -rw-r--r-- | src/filesys/filesys.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/src/filesys/filesys.c b/src/filesys/filesys.c index fedda08..d30f728 100644 --- a/src/filesys/filesys.c +++ b/src/filesys/filesys.c @@ -7,6 +7,11 @@ #include "filesys/inode.h" #include "filesys/directory.h" #include "devices/disk.h" +#include "threads/synch.h" + +/* Locks filesys_create so the same file isn't + created twice with the same name. */ +static struct lock create_lock; /* The disk that contains the file system. */ struct disk *filesys_disk; @@ -22,6 +27,8 @@ filesys_init (bool format) if (filesys_disk == NULL) PANIC ("hd0:1 (hdb) not present, file system initialization failed"); + lock_init (&create_lock); + inode_init (); free_map_init (); @@ -48,12 +55,14 @@ filesys_create (const char *name, off_t initial_size) { disk_sector_t inode_sector = 0; struct dir *dir = dir_open_root (); + lock_acquire (&create_lock); bool success = (dir != NULL - && free_map_allocate (1, &inode_sector) - && inode_create (inode_sector, initial_size) - && dir_add (dir, name, inode_sector)); - if (!success && inode_sector != 0) - free_map_release (inode_sector, 1); + && free_map_allocate (1, &inode_sector) // find sector + && inode_create (inode_sector, initial_size) // create inode pointing to sector + && dir_add (dir, name, inode_sector)); // add dir entry pointing to inode + lock_release (&create_lock); + if (!success && inode_sector != 0) // oops, we got a sector but file creation failed + free_map_release (inode_sector, 1); // so deallocate the sector dir_close (dir); return success; |