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fix: unwritten sparse file regions could get corrupted if the end of a 

write wasn't aligned to cluster boundary.
master
szaka 2007-10-03 21:09:30 +00:00
parent 2caeb1b4e4
commit d4b4b41191
1 changed files with 19 additions and 11 deletions
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30
libntfs-3g/attrib.c
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@ -1098,7 +1098,7 @@ s64 ntfs_attr_pwrite(ntfs_attr *na, const s64 pos, s64 count, const void *b)
ntfs_volume *vol;
ntfs_attr_search_ctx *ctx = NULL;
runlist_element *rl;
int eo;
s64 eo, hole;
struct {
unsigned int undo_initialized_size : 1;
unsigned int undo_data_size : 1;
@ -1245,7 +1245,7 @@ s64 ntfs_attr_pwrite(ntfs_attr *na, const s64 pos, s64 count, const void *b)
* length.
*/
ofs = pos - (rl->vcn << vol->cluster_size_bits);
for (; count; rl++, ofs = 0) {
for (hole = 0; count; rl++, ofs = 0, hole = 0) {
if (rl->lcn == LCN_RL_NOT_MAPPED) {
rl = ntfs_attr_find_vcn(na, rl->vcn);
if (!rl) {
@ -1265,6 +1265,8 @@ s64 ntfs_attr_pwrite(ntfs_attr *na, const s64 pos, s64 count, const void *b)
goto rl_err_out;
}
if (rl->lcn < (LCN)0) {
hole = rl->vcn + rl->length;
if (rl->lcn != (LCN)LCN_HOLE) {
errno = EIO;
@ -1284,20 +1286,26 @@ retry:
if (!NVolReadOnly(vol)) {
s64 pos = (rl->lcn << vol->cluster_size_bits) + ofs;
int bsize = vol->cluster_size;
u32 bsize = vol->cluster_size;
s64 wend = (rl->vcn << vol->cluster_size_bits) + ofs + to_write;
s64 rounded = ((wend + bsize - 1) & ~(s64)(bsize - 1)) - wend;
/*
* Write cluster size blocks if it's possible. This will
* cause the kernel not to seek and read disk blocks for
* filling the end of the buffer which increases write
* speed at least by 2-11 fold typically.
* Zero fill to cluster boundary if we're writing to an
* ex-sparse cluster or we're at the end of the attribute.
* This will cause the kernel not to seek and read disk
* blocks during write(2) to fill the end of the buffer
* which increases write speed by 2-10 fold typically.
*/
if (!(ofs % bsize) && (to_write % bsize) &&
((ofs + to_write) == na->initialized_size)) {
if ((rounded && (wend < (hole << vol->cluster_size_bits))) ||
(((to_write % bsize) &&
(ofs + to_write == na->initialized_size)))) {
s64 rounded = (to_write + bsize - 1) & ~(bsize - 1);
char *cb = ntfs_malloc(rounded);
char *cb;
rounded += to_write;
cb = ntfs_malloc(rounded);
if (!cb)
goto err_out;