hfs-556.100.11.tar.gz

[apple/hfs.git] / core / hfs_readwrite.c

diff --git a/core/hfs_readwrite.c b/core/hfs_readwrite.c
index d7a070e2101a44e50d11c463b22b9b86756a155b..068fca34bc4fa64507676069c9a6e527fad116cd 100644 (file)
--- a/core/hfs_readwrite.c
+++ b/core/hfs_readwrite.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000-2015 Apple Inc. All rights reserved.
+ * Copyright (c) 2000-2020 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
@@ -2911,22 +2911,53 @@ fail_change_next_allocation:
                                                         NULL);
 
        case FSIOC_CAS_BSDFLAGS: {
-               if (hfsmp->hfs_flags & HFS_READ_ONLY) {
-                       return (EROFS);
-               }
-
-#if 0
                struct fsioc_cas_bsdflags *cas = (void *)ap->a_data;
                struct cnode *cp = VTOC(vp);
                u_int32_t document_id = 0;
+               bool need_truncate = false;
                int decmpfs_reset_state = 0;
                int error;
 
+               if (hfsmp->hfs_flags & HFS_READ_ONLY) {
+                       return (EROFS);
+               }
+
                /* Don't allow modification of the journal. */
                if (hfs_is_journal_file(hfsmp, cp)) {
                        return (EPERM);
                }
 
+               // Check if we need to set UF_COMPRESSED.
+               // If so, ask decmpfs if we're allowed to (and if so, if we need to truncate
+               // the data fork to 0).
+               if (!(cas->expected_flags & UF_COMPRESSED) && (cas->new_flags & UF_COMPRESSED)) {
+                       struct vnode_attr vap;
+                       VATTR_INIT(&vap);
+                       VATTR_SET(&vap, va_flags, cas->new_flags);
+
+                       error = decmpfs_update_attributes(vp, &vap);
+                       if (error) {
+                               return (error);
+                       }
+
+                       // Similar to hfs_vnop_setattr(), we call decmpfs_update_attributes()
+                       // as it is the ultimate arbiter of whether or not UF_COMPRESSED can be set.
+                       // (If the decmpfs xattr is not present or invalid, for example,
+                       // UF_COMPRESSED should *not* be set.)
+                       // It will also tell us if we need to truncate the data fork to 0.
+                       if (!(vap.va_flags & UF_COMPRESSED)) {
+                               // The request to update UF_COMPRESSED is denied.
+                               // (Note that decmpfs_update_attributes() won't touch va_active
+                               // in this case.) Error out.
+                               return (EPERM);
+                       }
+
+                       if (VATTR_IS_ACTIVE(&vap, va_data_size) && (vap.va_data_size == 0)) {
+                               // We must also truncate this file's data fork to 0.
+                               need_truncate = true;
+                       }
+               }
+
                if ((error = hfs_lock(cp, HFS_EXCLUSIVE_LOCK, HFS_LOCK_DEFAULT))) {
                        return (error);
                }
@@ -2973,17 +3004,11 @@ fail_change_next_allocation:
                        }
                }
 
-               bool setting_compression = false;
-
-               if (!(cas->actual_flags & UF_COMPRESSED) && (cas->new_flags & UF_COMPRESSED))
-                       setting_compression = true;
-
-               if (setting_compression) {
+               // Attempt to truncate our data fork to 0 length, if necessary.
+               if (need_truncate && (VTOF(vp)->ff_size)) {
                        hfs_lock_truncate(cp, HFS_EXCLUSIVE_LOCK, HFS_LOCK_DEFAULT);
-                       if (VTOF(vp)->ff_size) {
-                               // hfs_truncate will deal with the cnode lock
-                               error = hfs_truncate(vp, 0, IO_NDELAY, 0, ap->a_context);
-                       }
+                       // hfs_truncate will deal with the cnode lock
+                       error = hfs_truncate(vp, 0, IO_NDELAY, 0, ap->a_context);
                        hfs_unlock_truncate(cp, HFS_LOCK_DEFAULT);
                }
 
@@ -3021,9 +3046,7 @@ fail_change_next_allocation:
                        decmpfs_cnode_set_vnode_state(dp, FILE_TYPE_UNKNOWN, 0);
                }
 #endif
-               break;
-#endif
-               return ENOTSUP;
+               break; // return 0 below
        }
 
        default:
@@ -3459,8 +3482,41 @@ retry:
                }
        }
 
+#if NEW_XATTR
+       // check for the alternate xattr vnode
+       if (vp == hfsmp->hfs_attrdata_vp) {
+               HFSPlusExtentDescriptor real_fext;
+               size_t availableBytes;
+               u_int32_t sectorsPerBlock;              // Number of sectors per allocation block
+               u_int32_t sectorSize;
+               uint64_t f_offset;
+
+               if (!hfs_xattr_fext_find(&hfsmp->hfs_xattr_io, hfsmp->blockSize,
+                                                                ap->a_foffset, &real_fext, &f_offset)) {
+                       panic("cannot find xattr fext for %llu", f_offset);
+               }
+
+               sectorSize = hfsmp->hfs_logical_block_size;
+               //      Compute the number of sectors in an allocation block
+               sectorsPerBlock = hfsmp->blockSize / sectorSize;
+
+               *ap->a_bpn = (f_offset / hfsmp->blockSize) * sectorsPerBlock;
+               availableBytes = real_fext.blockCount * hfsmp->blockSize - (f_offset - (real_fext.startBlock * hfsmp->blockSize));
+               if (availableBytes < bytesContAvail) {
+                       bytesContAvail = availableBytes;
+               }
+
+               goto got_fext;
+       }
+#endif
+
        retval = MapFileBlockC(hfsmp, (FCB *)fp, bytesContAvail, ap->a_foffset,
                               ap->a_bpn, &bytesContAvail);
+
+#if NEW_XATTR
+got_fext:
+#endif
+
        if (syslocks) {
                hfs_systemfile_unlock(hfsmp, lockflags);
                syslocks = 0;
@@ -4279,7 +4335,8 @@ hfs_vnop_allocate(struct vnop_allocate_args /* {
        hfs_lock_truncate(cp, HFS_EXCLUSIVE_LOCK, HFS_LOCK_DEFAULT);
 
        if ((retval = hfs_lock(cp, HFS_EXCLUSIVE_LOCK, HFS_LOCK_DEFAULT))) {
-               goto Err_Exit;
+               hfs_unlock_truncate(cp, HFS_LOCK_DEFAULT);
+               return (retval);
        }
        
        fp = VTOF(vp);