+/*
+ * Preparation which must be done prior to deleting the catalog record
+ * of a file or directory. In order to make the on-disk as safe as possible,
+ * we remove the catalog entry before releasing the bitmap blocks and the
+ * overflow extent records. However, some work must be done prior to deleting
+ * the catalog record.
+ *
+ * When calling this function, the cnode must exist both in memory and on-disk.
+ * If there are both resource fork and data fork vnodes, this function should
+ * be called on both.
+ */
+
+int
+hfs_prepare_release_storage (struct hfsmount *hfsmp, struct vnode *vp) {
+
+ struct filefork *fp = VTOF(vp);
+ struct cnode *cp = VTOC(vp);
+#if QUOTA
+ int retval = 0;
+#endif /* QUOTA */
+
+ /* Cannot truncate an HFS directory! */
+ if (vnode_isdir(vp)) {
+ return (EISDIR);
+ }
+
+ /*
+ * See the comment below in hfs_truncate for why we need to call
+ * setsize here. Essentially we want to avoid pending IO if we
+ * already know that the blocks are going to be released here.
+ * This function is only called when totally removing all storage for a file, so
+ * we can take a shortcut and immediately setsize (0);
+ */
+ ubc_setsize(vp, 0);
+
+ /* This should only happen with a corrupt filesystem */
+ if ((off_t)fp->ff_size < 0)
+ return (EINVAL);
+
+ /*
+ * We cannot just check if fp->ff_size == length (as an optimization)
+ * since there may be extra physical blocks that also need truncation.
+ */
+#if QUOTA
+ if ((retval = hfs_getinoquota(cp))) {
+ return(retval);
+ }
+#endif /* QUOTA */
+
+ /* Wipe out any invalid ranges which have yet to be backed by disk */
+ rl_remove(0, fp->ff_size - 1, &fp->ff_invalidranges);
+
+ /*
+ * Account for any unmapped blocks. Since we're deleting the
+ * entire file, we don't have to worry about just shrinking
+ * to a smaller number of borrowed blocks.
+ */
+ if (fp->ff_unallocblocks > 0) {
+ u_int32_t loanedBlocks;
+
+ hfs_lock_mount (hfsmp);
+ loanedBlocks = fp->ff_unallocblocks;
+ cp->c_blocks -= loanedBlocks;
+ fp->ff_blocks -= loanedBlocks;
+ fp->ff_unallocblocks = 0;
+
+ hfsmp->loanedBlocks -= loanedBlocks;
+
+ hfs_unlock_mount (hfsmp);
+ }
+
+ return 0;
+}
+
+
+/*
+ * Special wrapper around calling TruncateFileC. This function is useable
+ * even when the catalog record does not exist any longer, making it ideal
+ * for use when deleting a file. The simplification here is that we know
+ * that we are releasing all blocks.
+ *
+ * Note that this function may be called when there is no vnode backing
+ * the file fork in question. We may call this from hfs_vnop_inactive
+ * to clear out resource fork data (and may not want to clear out the data
+ * fork yet). As a result, we pointer-check both sets of inputs before
+ * doing anything with them.
+ *
+ * The caller is responsible for saving off a copy of the filefork(s)
+ * embedded within the cnode prior to calling this function. The pointers
+ * supplied as arguments must be valid even if the cnode is no longer valid.
+ */
+
+int
+hfs_release_storage (struct hfsmount *hfsmp, struct filefork *datafork,
+ struct filefork *rsrcfork, u_int32_t fileid) {
+
+ off_t filebytes;
+ u_int32_t fileblocks;
+ int blksize = 0;
+ int error = 0;
+ int lockflags;
+
+ blksize = hfsmp->blockSize;
+
+ /* Data Fork */
+ if (datafork) {
+ datafork->ff_size = 0;
+
+ fileblocks = datafork->ff_blocks;
+ filebytes = (off_t)fileblocks * (off_t)blksize;
+
+ /* We killed invalid ranges and loaned blocks before we removed the catalog entry */
+
+ while (filebytes > 0) {
+ if (filebytes > HFS_BIGFILE_SIZE) {
+ filebytes -= HFS_BIGFILE_SIZE;
+ } else {
+ filebytes = 0;
+ }
+
+ /* Start a transaction, and wipe out as many blocks as we can in this iteration */
+ if (hfs_start_transaction(hfsmp) != 0) {
+ error = EINVAL;
+ break;
+ }
+
+ if (datafork->ff_unallocblocks == 0) {
+ /* Protect extents b-tree and allocation bitmap */
+ lockflags = SFL_BITMAP;
+ if (overflow_extents(datafork))
+ lockflags |= SFL_EXTENTS;
+ lockflags = hfs_systemfile_lock(hfsmp, lockflags, HFS_EXCLUSIVE_LOCK);
+
+ error = MacToVFSError(TruncateFileC(HFSTOVCB(hfsmp), datafork, filebytes, 1, 0, fileid, false));
+
+ hfs_systemfile_unlock(hfsmp, lockflags);
+ }
+ (void) hfs_volupdate(hfsmp, VOL_UPDATE, 0);
+
+ /* Finish the transaction and start over if necessary */
+ hfs_end_transaction(hfsmp);
+
+ if (error) {
+ break;
+ }
+ }
+ }
+
+ /* Resource fork */
+ if (error == 0 && rsrcfork) {
+ rsrcfork->ff_size = 0;
+
+ fileblocks = rsrcfork->ff_blocks;
+ filebytes = (off_t)fileblocks * (off_t)blksize;
+
+ /* We killed invalid ranges and loaned blocks before we removed the catalog entry */
+
+ while (filebytes > 0) {
+ if (filebytes > HFS_BIGFILE_SIZE) {
+ filebytes -= HFS_BIGFILE_SIZE;
+ } else {
+ filebytes = 0;
+ }
+
+ /* Start a transaction, and wipe out as many blocks as we can in this iteration */
+ if (hfs_start_transaction(hfsmp) != 0) {
+ error = EINVAL;
+ break;
+ }
+
+ if (rsrcfork->ff_unallocblocks == 0) {
+ /* Protect extents b-tree and allocation bitmap */
+ lockflags = SFL_BITMAP;
+ if (overflow_extents(rsrcfork))
+ lockflags |= SFL_EXTENTS;
+ lockflags = hfs_systemfile_lock(hfsmp, lockflags, HFS_EXCLUSIVE_LOCK);
+
+ error = MacToVFSError(TruncateFileC(HFSTOVCB(hfsmp), rsrcfork, filebytes, 1, 1, fileid, false));
+
+ hfs_systemfile_unlock(hfsmp, lockflags);
+ }
+ (void) hfs_volupdate(hfsmp, VOL_UPDATE, 0);
+
+ /* Finish the transaction and start over if necessary */
+ hfs_end_transaction(hfsmp);
+
+ if (error) {
+ break;
+ }
+ }
+ }
+
+ return error;
+}
+
+errno_t hfs_ubc_setsize(vnode_t vp, off_t len, bool have_cnode_lock)
+{
+ errno_t error;
+
+ /*
+ * Call ubc_setsize to give the VM subsystem a chance to do
+ * whatever it needs to with existing pages before we delete
+ * blocks. Note that symlinks don't use the UBC so we'll
+ * get back ENOENT in that case.
+ */
+ if (have_cnode_lock) {
+ error = ubc_setsize_ex(vp, len, UBC_SETSIZE_NO_FS_REENTRY);
+ if (error == EAGAIN) {
+ cnode_t *cp = VTOC(vp);
+
+ if (cp->c_truncatelockowner != current_thread()) {
+#if DEVELOPMENT || DEBUG
+ panic("hfs: hfs_ubc_setsize called without exclusive truncate lock!");
+#else
+ printf("hfs: hfs_ubc_setsize called without exclusive truncate lock!\n");
+#endif
+ }
+
+ hfs_unlock(cp);
+ error = ubc_setsize_ex(vp, len, 0);
+ hfs_lock_always(cp, HFS_EXCLUSIVE_LOCK);
+ }
+ } else
+ error = ubc_setsize_ex(vp, len, 0);
projects / apple / xnu.git / blobdiff