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authorBenoît Thébaudeau <benoit@wsystem.com>2015-09-28 15:45:32 +0200
committerTom Rini <trini@konsulko.com>2015-10-11 17:12:08 -0400
commit1254b44a9f31c78ce7325eb392eaa949a2c7fc9a (patch)
treec02399fd3ce118719e0f209234747b82509102d3
parente876be4b5ccb661d68b5b83330e134ace339316c (diff)
downloadblackbird-obmc-uboot-1254b44a9f31c78ce7325eb392eaa949a2c7fc9a.tar.gz
blackbird-obmc-uboot-1254b44a9f31c78ce7325eb392eaa949a2c7fc9a.zip
fs/fat/fat_write: Fix management of empty files
Overwriting an empty file not created by U-Boot did not work, and it could even corrupt the FAT. Moreover, creating empty files or emptying existing files allocated a cluster, which is not standard. Fix this by always keeping empty files clusterless as specified by Microsoft (the start cluster must be set to 0 in the directory entry in that case), and by supporting overwriting such files. Signed-off-by: Benoît Thébaudeau <benoit@wsystem.com>
-rw-r--r--fs/fat/fat_write.c85
1 files changed, 64 insertions, 21 deletions
diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c
index 2d032ee5ec..af828d07bd 100644
--- a/fs/fat/fat_write.c
+++ b/fs/fat/fat_write.c
@@ -710,6 +710,14 @@ set_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
debug("%llu bytes\n", filesize);
+ if (!curclust) {
+ if (filesize) {
+ debug("error: nonempty clusterless file!\n");
+ return -1;
+ }
+ return 0;
+ }
+
actsize = bytesperclust;
endclust = curclust;
do {
@@ -765,15 +773,24 @@ getit:
}
/*
- * Fill dir_entry
+ * Set start cluster in directory entry
*/
-static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
- const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
+static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
+ __u32 start_cluster)
{
if (mydata->fatsize == 32)
dentptr->starthi =
cpu_to_le16((start_cluster & 0xffff0000) >> 16);
dentptr->start = cpu_to_le16(start_cluster & 0xffff);
+}
+
+/*
+ * Fill dir_entry
+ */
+static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
+ const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
+{
+ set_start_cluster(mydata, dentptr, start_cluster);
dentptr->size = cpu_to_le32(size);
dentptr->attr = attr;
@@ -1030,32 +1047,58 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
retdent->size = cpu_to_le32(size);
start_cluster = START(retdent);
- ret = check_overflow(mydata, start_cluster, size);
- if (ret) {
- printf("Error: %llu overflow\n", size);
- goto exit;
- }
+ if (start_cluster) {
+ if (size) {
+ ret = check_overflow(mydata, start_cluster,
+ size);
+ if (ret) {
+ printf("Error: %llu overflow\n", size);
+ goto exit;
+ }
+ }
+
+ ret = clear_fatent(mydata, start_cluster);
+ if (ret) {
+ printf("Error: clearing FAT entries\n");
+ goto exit;
+ }
- ret = clear_fatent(mydata, start_cluster);
- if (ret) {
- printf("Error: clearing FAT entries\n");
- goto exit;
+ if (!size)
+ set_start_cluster(mydata, retdent, 0);
+ } else if (size) {
+ ret = start_cluster = find_empty_cluster(mydata);
+ if (ret < 0) {
+ printf("Error: finding empty cluster\n");
+ goto exit;
+ }
+
+ ret = check_overflow(mydata, start_cluster, size);
+ if (ret) {
+ printf("Error: %llu overflow\n", size);
+ goto exit;
+ }
+
+ set_start_cluster(mydata, retdent, start_cluster);
}
} else {
/* Set short name to set alias checksum field in dir_slot */
set_name(empty_dentptr, filename);
fill_dir_slot(mydata, &empty_dentptr, filename);
- ret = start_cluster = find_empty_cluster(mydata);
- if (ret < 0) {
- printf("Error: finding empty cluster\n");
- goto exit;
- }
+ if (size) {
+ ret = start_cluster = find_empty_cluster(mydata);
+ if (ret < 0) {
+ printf("Error: finding empty cluster\n");
+ goto exit;
+ }
- ret = check_overflow(mydata, start_cluster, size);
- if (ret) {
- printf("Error: %llu overflow\n", size);
- goto exit;
+ ret = check_overflow(mydata, start_cluster, size);
+ if (ret) {
+ printf("Error: %llu overflow\n", size);
+ goto exit;
+ }
+ } else {
+ start_cluster = 0;
}
/* Set attribute as archieve for regular file */
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