diff options
| -rw-r--r-- | libdiskfs/dir-link.c | 91 |
1 files changed, 62 insertions, 29 deletions
diff --git a/libdiskfs/dir-link.c b/libdiskfs/dir-link.c index f47ad85b..9bff1c9a 100644 --- a/libdiskfs/dir-link.c +++ b/libdiskfs/dir-link.c @@ -22,10 +22,12 @@ kern_return_t diskfs_S_dir_link (struct protid *dircred, struct protid *filecred, - char *name) + char *name, + int excl) { - struct node *np; - struct node *dnp; + struct node *np; /* node being linked */ + struct node *tnp; /* node being deleted implicitly */ + struct node *dnp; /* directory of new entry */ struct dirstat *ds = alloca (diskfs_dirstat_size); error_t error; @@ -50,45 +52,76 @@ diskfs_S_dir_link (struct protid *dircred, dnp = dircred->po->np; mutex_lock (&dnp->lock); - /* This lock is safe since a non-directory is inherently a leaf */ - mutex_lock (&np->lock); - - if (np->dn_stat.st_nlink == diskfs_link_max - 1) + /* Lookup new location */ + error = diskfs_lookup (dnp, name, RENAME, &tnp, ds, dircred); + if (!error && excl) { - error = EMLINK; - goto out; + error = EEXIST; + diskfs_nput (tnp); + } + if (error && error != ENOENT) + { + diskfs_drop_dirstat (dnp, ds); + mutex_unlock (&dnp->lock); + return error; } - error = diskfs_lookup (dnp, name, CREATE, 0, ds, dircred); - - if (error == EAGAIN) - error = EEXIST; - if (!error) - error = EEXIST; - if (error != ENOENT) + if (np == tnp) { diskfs_drop_dirstat (dnp, ds); - goto out; + mutex_unlock (&dnp->lock); + mutex_unlock (&tnp->lock); + mach_port_deallocate (mach_task_self (), filecred->pi.port_right); + return 0; } + if (tnp && S_ISDIR (tnp->dn_stat.st_mode)) + { + diskfs_drop_dirstat (dnp, ds); + mutex_unlock (&dnp->lock); + mutex_unlock (&tnp->lock); + return EISDIR; + } + + /* Create new entry for NP */ + + /* This is safe because NP is not a directory (thus not DNP) and + not TNP and is a leaf. */ + mutex_lock (&np->lock); + + /* Increment link count */ + if (np->dn_stat.st_nlink == diskfs_link_max - 1) + { + diskfs_drop_dirstat (dnp, ds); + mutex_unlock (&np->lock); + mutex_unlock (&dnp->lock); + return EMLINK; + } np->dn_stat.st_nlink++; np->dn_set_ctime = 1; - diskfs_node_update (np, 1); - - error = diskfs_direnter (dnp, name, np, ds, dircred); - if (error) + + /* Attach it */ + if (tnp) { - np->dn_stat.st_nlink--; - np->dn_set_ctime = 1; - if (diskfs_synchronous) - diskfs_node_update (np, 1); + assert (!excl); + error = diskfs_dirrewrite (dp, tnp, np, name, ds); + if (!error) + { + /* Deallocate link on TNP */ + tnp->dn_stat.st_nlink--; + tnp->dn_set_ctime = 1; + if (diskfs_synchronous) + diskfs_node_update (tnp, 1); + } + diskfs_nput (tnp); } - + else + error = diskfs_direnter (dp, name, np, ds, dircred); + if (diskfs_synchronous) - diskfs_node_update (dnp, 1); - - out: + diskfs_node_update (dp, 1); + mutex_unlock (&dnp->lock); mutex_unlock (&np->lock); if (!error) |