From: AKASHI Takahiro <takahiro.aka...@linaro.org>
In my attempt to re-work write operation, it was revealed that iterator's
"clust" does not always point to a cluster to which a current directory
entry ("dent") belongs.
This patch assures that it is always true by adding "next_clust" which is
used solely for dereferencing a cluster chain.
Signed-off-by: AKASHI Takahiro <takahiro.aka...@linaro.org>
---
fs/fat/fat.c | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)
diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index eaea9300fd7f..afb8b3f9ef1a 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -641,6 +641,7 @@ static int get_fs_info(fsdata *mydata)
typedef struct {
fsdata *fsdata; /* filesystem parameters */
unsigned clust; /* current cluster */
+ unsigned next_clust; /* next cluster if remaining == 0 */
int last_cluster; /* set once we've read last cluster */
int is_root; /* is iterator at root directory */
int remaining; /* remaining dent's in current cluster */
@@ -672,6 +673,7 @@ static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
itr->fsdata = fsdata;
itr->clust = fsdata->root_cluster;
+ itr->next_clust = fsdata->root_cluster;
itr->dent = NULL;
itr->remaining = 0;
itr->last_cluster = 0;
@@ -707,9 +709,11 @@ static void fat_itr_child(fat_itr *itr, fat_itr *parent)
itr->fsdata = parent->fsdata;
if (clustnum > 0) {
itr->clust = clustnum;
+ itr->next_clust = clustnum;
itr->is_root = 0;
} else {
itr->clust = parent->fsdata->root_cluster;
+ itr->next_clust = parent->fsdata->root_cluster;
itr->is_root = 1;
}
itr->dent = NULL;
@@ -727,7 +731,7 @@ static void *next_cluster(fat_itr *itr)
if (itr->last_cluster)
return NULL;
- sect = clust_to_sect(itr->fsdata, itr->clust);
+ sect = clust_to_sect(itr->fsdata, itr->next_clust);
debug("FAT read(sect=%d), clust_size=%d, DIRENTSPERBLOCK=%zd\n",
sect, itr->fsdata->clust_size, DIRENTSPERBLOCK);
@@ -748,18 +752,19 @@ static void *next_cluster(fat_itr *itr)
return NULL;
}
+ itr->clust = itr->next_clust;
if (itr->is_root && itr->fsdata->fatsize != 32) {
- itr->clust++;
- sect = clust_to_sect(itr->fsdata, itr->clust);
+ itr->next_clust++;
+ sect = clust_to_sect(itr->fsdata, itr->next_clust);
if (sect - itr->fsdata->rootdir_sect >=
itr->fsdata->rootdir_size) {
- debug("cursect: 0x%x\n", itr->clust);
+ debug("nextclust: 0x%x\n", itr->next_clust);
itr->last_cluster = 1;
}
} else {
- itr->clust = get_fatent(itr->fsdata, itr->clust);
- if (CHECK_CLUST(itr->clust, itr->fsdata->fatsize)) {
- debug("cursect: 0x%x\n", itr->clust);
+ itr->next_clust = get_fatent(itr->fsdata, itr->next_clust);
+ if (CHECK_CLUST(itr->next_clust, itr->fsdata->fatsize)) {
+ debug("nextclust: 0x%x\n", itr->next_clust);
itr->last_cluster = 1;
}
}
@@ -775,8 +780,11 @@ static dir_entry *next_dent(fat_itr *itr)
itr->fsdata->clust_size;
/* have we reached the last cluster? */
- if (!dent)
+ if (!dent) {
+ /* a sign for no more entries left */
+ itr->dent = NULL;
return NULL;
+ }
itr->remaining = nbytes / sizeof(dir_entry) - 1;
itr->dent = dent;
@@ -937,6 +945,7 @@ static int fat_itr_resolve(fat_itr *itr, const char *path,
unsigned type)
(((next - path) == 2) && !strncmp(path, "..", 2))) {
/* point back to itself */
itr->clust = itr->fsdata->root_cluster;
+ itr->next_clust = itr->fsdata->root_cluster;
itr->dent = NULL;
itr->remaining = 0;
itr->last_cluster = 0;
--
2.18.0
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