fs: fat: extend FAT write operations

get_fs_info() was introduced in major re-work of read operation by Rob. We want to reuse this function in write operation by extending it with additional members in fsdata structure.

Signed-off-by AKASHI Takahiro <[email protected]>

---
 fs/fat/fat.c  | 3 +++
 include/fat.h | 2 ++
 2 files changed, 5 insertions(+)

fs/fat/fat.c +3 -0

index 4efe8a3eda..b48f48a751 100644
@@ -556,6 +556,9 @@ static int get_fs_info(fsdata *mydata)
 		return ret;
 	}
 
+	mydata->bs_total_sect = bs.total_sect;
+	mydata->bs_fats = bs.fats;
+
 	if (mydata->fatsize == 32) {
 		mydata->fatlength = bs.fat32_length;
 	} else {

include/fat.h +0 -0

index 09e1423685..0c88b59a4a 100644

include/fat.h +1 -0

+	__u8	bs_fats;	/* Boot sector's number of FATs */
 } fsdata;
 
 static inline u32 clust_to_sect(fsdata *fsdata, u32 clust)

Quoted 18 lines · AKASHI Takahiro

get_fs_info() was introduced in major re-work of read operation by Rob. We want to reuse this function in write operation by extending it with additional members in fsdata structure.

Signed-off-by AKASHI Takahiro <[email protected]>

---
 fs/fat/fat.c  | 3 +++
 include/fat.h | 2 ++
 2 files changed, 5 insertions(+)

fs/fat/fat.c +0 -0

index 4efe8a3eda..b48f48a751 100644
@@ -556,6 +556,9 @@ static int get_fs_info(fsdata *mydata)
 		return ret;
 	}
 

fs/fat/fat.c static int get_fs_info(fsdata *mydata) · line 559

Quoted 1 line

fs/fat/fat.c +1 -0

+	mydata->bs_total_sect = bs.total_sect;

Quoted 6 lines

fs/fat/fat.c +2 -0

+	mydata->bs_fats = bs.fats;
+
 	if (mydata->fatsize == 32) {
 		mydata->fatlength = bs.fat32_length;
 	} else {

include/fat.h +0 -0

include/fat.h typedef struct { · line 176

Quoted 8 lines

index 09e1423685..0c88b59a4a 100644

include/fat.h +1 -0

@@ -173,6 +173,8 @@ typedef struct {
 	int	fatbufnum;	/* Used by get_fatent, init to -1 */
 	int	rootdir_size;	/* Size of root dir for non-FAT32 */
 	__u32	root_cluster;	/* First cluster of root dir for FAT32 */
+	__u32	bs_total_sect;	/* Boot sector's number of sectors */

How can one sector have multiple sectors? Please, reword the comment to something more obvious.

Best regards

Heinrich

include/fat.h typedef struct { · line 177

Quoted 1 line

include/fat.h +1 -0

+	__u8	bs_fats;	/* Boot sector's number of FATs */

Quoted 4 lines

include/fat.h +0 -0

 } fsdata;
 
 static inline u32 clust_to_sect(fsdata *fsdata, u32 clust)

FAT's root directory does not have "." nor ".."
So care must be taken when scanning root directory with fat_itr_resolve(). Without this patch, any file path starting with "." or ".." will not be resolved at all.

Signed-off-by AKASHI Takahiro <[email protected]>

---
 fs/fat/fat.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

fs/fat/fat.c +0 -0

index b48f48a751..fd6523c66b 100644

fs/fat/fat.c +19 -0

+		if ((((next - path) == 1) && !strncmp(path, ".", 1)) ||
+		    (((next - path) == 2) && !strncmp(path, "..", 2))) {
+			/* point back to itself */
+			itr->clust = itr->fsdata->root_cluster;
+			itr->dent = NULL;
+			itr->remaining = 0;
+			itr->last_cluster = 0;
+
+			if (next[0] == 0) {
+				if (type & TYPE_DIR)
+					return 0;
+				else
+					return -ENOENT;
+			}
+
+			return fat_itr_resolve(itr, next, type);
+		}
+	}
+
 	while (fat_itr_next(itr)) {
 		int match = 0;
 		unsigned n = max(strlen(itr->name), (size_t)(next - path));

Quoted 18 lines · AKASHI Takahiro

FAT's root directory does not have "." nor ".."
So care must be taken when scanning root directory with fat_itr_resolve(). Without this patch, any file path starting with "." or ".." will not be resolved at all.

Signed-off-by AKASHI Takahiro <[email protected]>

---
 fs/fat/fat.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

fs/fat/fat.c +0 -0

index b48f48a751..fd6523c66b 100644
@@ -927,6 +927,27 @@ static int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
 	while (next[0] && !ISDIRDELIM(next[0]))
 		next++;
 

fs/fat/fat.c static int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type) · line 931

Quoted 2 lines

fs/fat/fat.c +2 -0

+	if (itr->is_root) {
+		/* root dir doesn't have "." nor ".." */

I understand why root has no ../ but /./ should be valid.

On Linux 'ls /./' displays the root directory.

Best regards

Heinrich

Quoted 23 lines

fs/fat/fat.c +19 -0

+		if ((((next - path) == 1) && !strncmp(path, ".", 1)) ||
+		    (((next - path) == 2) && !strncmp(path, "..", 2))) {
+			/* point back to itself */
+			itr->clust = itr->fsdata->root_cluster;
+			itr->dent = NULL;
+			itr->remaining = 0;
+			itr->last_cluster = 0;
+
+			if (next[0] == 0) {
+				if (type & TYPE_DIR)
+					return 0;
+				else
+					return -ENOENT;
+			}
+
+			return fat_itr_resolve(itr, next, type);
+		}
+	}
+
 	while (fat_itr_next(itr)) {
 		int match = 0;
 		unsigned n = max(strlen(itr->name), (size_t)(next - path));

Directory iterator was introduced in major re-work of read operation by Rob. We want to use it for write operation extensively as well. This patch makes relevant functions, as well as iterator defition, visible outside of fat.c.

Signed-off-by AKASHI Takahiro <[email protected]>

---
 fs/fat/fat.c  | 39 ++++++---------------------------------
 include/fat.h | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 33 deletions(-)

fs/fat/fat.c +6 -33

index fd6523c66b..0f82cbe1bd 100644
@@ -634,25 +634,6 @@ static int get_fs_info(fsdata *mydata)
  * For more complete example, see fat_itr_resolve()
  */
 
-typedef struct {
-	fsdata    *fsdata;        /* filesystem parameters */
-	unsigned   clust;         /* current cluster */
-	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 */
-
-	/* current iterator position values: */
-	dir_entry *dent;          /* current directory entry */
-	char       l_name[VFAT_MAXLEN_BYTES];    /* long (vfat) name */
-	char       s_name[14];    /* short 8.3 name */
-	char      *name;          /* l_name if there is one, else s_name */
-
-	/* storage for current cluster in memory: */
-	u8         block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
-} fat_itr;
-
-static int fat_itr_isdir(fat_itr *itr);
-
 /**
  * fat_itr_root() - initialize an iterator to start at the root
  * directory

@@ -661,7 +642,7 @@ static int fat_itr_isdir(fat_itr *itr);
  * @fsdata: filesystem data for the partition
  * @return 0 on success, else -errno
  */
-static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
+int fat_itr_root(fat_itr *itr, fsdata *fsdata)
 {
 	if (get_fs_info(fsdata))
 		return -ENXIO;

@@ -693,7 +674,7 @@ static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
  * @parent: the iterator pointing at a directory entry in the
  *    parent directory of the directory to iterate
  */
-static void fat_itr_child(fat_itr *itr, fat_itr *parent)
+void fat_itr_child(fat_itr *itr, fat_itr *parent)
 {
 	fsdata *mydata = parent->fsdata;  /* for silly macros */
 	unsigned clustnum = START(parent->dent);

@@ -713,7 +694,7 @@ static void fat_itr_child(fat_itr *itr, fat_itr *parent)
 	itr->last_cluster = 0;
 }
 
-static void *next_cluster(fat_itr *itr)
+void *next_cluster(fat_itr *itr)
 {
 	fsdata *mydata = itr->fsdata;  /* for silly macros */
 	int ret;

@@ -834,7 +815,7 @@ static dir_entry *extract_vfat_name(fat_itr *itr)
  * @return boolean, 1 if success or 0 if no more entries in the
  *    current directory
  */
-static int fat_itr_next(fat_itr *itr)
+int fat_itr_next(fat_itr *itr)
 {
 	dir_entry *dent;
 

@@ -879,19 +860,11 @@ static int fat_itr_next(fat_itr *itr)
  * @itr: the iterator
  * @return true if cursor is at a directory
  */
-static int fat_itr_isdir(fat_itr *itr)
+int fat_itr_isdir(fat_itr *itr)
 {
 	return !!(itr->dent->attr & ATTR_DIR);
 }
 
-/*
- * Helpers:
- */
-
-#define TYPE_FILE 0x1
-#define TYPE_DIR  0x2
-#define TYPE_ANY  (TYPE_FILE | TYPE_DIR)
-
 /**
  * fat_itr_resolve() - traverse directory structure to resolve the
  * requested path.

@@ -907,7 +880,7 @@ static int fat_itr_isdir(fat_itr *itr)
  * @type: bitmask of allowable file types
  * @return 0 on success or -errno
  */
-static int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
+int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
 {
 	const char *next;
 

include/fat.h +0 -0

index 0c88b59a4a..577e6b4592 100644

include/fat.h +25 -0

+
+typedef struct {
+	fsdata    *fsdata;        /* filesystem parameters */
+	unsigned   clust;         /* current cluster */
+	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 */
+
+	/* current iterator position values: */
+	dir_entry *dent;          /* current directory entry */
+	char       l_name[VFAT_MAXLEN_BYTES];    /* long (vfat) name */
+	char       s_name[14];    /* short 8.3 name */
+	char      *name;          /* l_name if there is one, else s_name */
+
+	/* storage for current cluster in memory: */
+	u8         block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
+} fat_itr;
+
+int fat_itr_root(fat_itr *itr, fsdata *fsdata);
+void fat_itr_child(fat_itr *itr, fat_itr *parent);
+void *next_cluster(fat_itr *itr);
+int fat_itr_next(fat_itr *itr);
+int fat_itr_isdir(fat_itr *itr);
+int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type);
+
 int file_fat_detectfs(void);
 int fat_exists(const char *filename);
 int fat_size(const char *filename, loff_t *size);

Quoted 112 lines · AKASHI Takahiro

Directory iterator was introduced in major re-work of read operation by Rob. We want to use it for write operation extensively as well. This patch makes relevant functions, as well as iterator defition, visible outside of fat.c.

Signed-off-by AKASHI Takahiro <[email protected]>

---
 fs/fat/fat.c  | 39 ++++++---------------------------------
 include/fat.h | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 33 deletions(-)

fs/fat/fat.c +6 -33

index fd6523c66b..0f82cbe1bd 100644
@@ -634,25 +634,6 @@ static int get_fs_info(fsdata *mydata)
  * For more complete example, see fat_itr_resolve()
  */
 
-typedef struct {
-	fsdata    *fsdata;        /* filesystem parameters */
-	unsigned   clust;         /* current cluster */
-	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 */
-
-	/* current iterator position values: */
-	dir_entry *dent;          /* current directory entry */
-	char       l_name[VFAT_MAXLEN_BYTES];    /* long (vfat) name */
-	char       s_name[14];    /* short 8.3 name */
-	char      *name;          /* l_name if there is one, else s_name */
-
-	/* storage for current cluster in memory: */
-	u8         block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
-} fat_itr;
-
-static int fat_itr_isdir(fat_itr *itr);
-
 /**
  * fat_itr_root() - initialize an iterator to start at the root
  * directory

@@ -661,7 +642,7 @@ static int fat_itr_isdir(fat_itr *itr);
  * @fsdata: filesystem data for the partition
  * @return 0 on success, else -errno
  */
-static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
+int fat_itr_root(fat_itr *itr, fsdata *fsdata)
 {
 	if (get_fs_info(fsdata))
 		return -ENXIO;

@@ -693,7 +674,7 @@ static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
  * @parent: the iterator pointing at a directory entry in the
  *    parent directory of the directory to iterate
  */
-static void fat_itr_child(fat_itr *itr, fat_itr *parent)
+void fat_itr_child(fat_itr *itr, fat_itr *parent)
 {
 	fsdata *mydata = parent->fsdata;  /* for silly macros */
 	unsigned clustnum = START(parent->dent);

@@ -713,7 +694,7 @@ static void fat_itr_child(fat_itr *itr, fat_itr *parent)
 	itr->last_cluster = 0;
 }
 
-static void *next_cluster(fat_itr *itr)
+void *next_cluster(fat_itr *itr)
 {
 	fsdata *mydata = itr->fsdata;  /* for silly macros */
 	int ret;

@@ -834,7 +815,7 @@ static dir_entry *extract_vfat_name(fat_itr *itr)
  * @return boolean, 1 if success or 0 if no more entries in the
  *    current directory
  */
-static int fat_itr_next(fat_itr *itr)
+int fat_itr_next(fat_itr *itr)
 {
 	dir_entry *dent;
 

@@ -879,19 +860,11 @@ static int fat_itr_next(fat_itr *itr)
  * @itr: the iterator
  * @return true if cursor is at a directory
  */
-static int fat_itr_isdir(fat_itr *itr)
+int fat_itr_isdir(fat_itr *itr)
 {
 	return !!(itr->dent->attr & ATTR_DIR);
 }
 
-/*
- * Helpers:
- */
-
-#define TYPE_FILE 0x1
-#define TYPE_DIR  0x2
-#define TYPE_ANY  (TYPE_FILE | TYPE_DIR)
-
 /**
  * fat_itr_resolve() - traverse directory structure to resolve the
  * requested path.

@@ -907,7 +880,7 @@ static int fat_itr_isdir(fat_itr *itr)
  * @type: bitmask of allowable file types
  * @return 0 on success or -errno
  */
-static int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
+int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
 {
 	const char *next;
 

include/fat.h +0 -0

index 0c88b59a4a..577e6b4592 100644

include/fat.h static inline u32 sect_to_clust(fsdata *fsdata, int sect) · line 196

Quoted 10 lines

include/fat.h +7 -0

@@ -187,6 +187,38 @@ static inline u32 sect_to_clust(fsdata *fsdata, int sect)
 	return (sect - fsdata->data_begin) / fsdata->clust_size;
 }
 
+/*
+ * Directory iterator
+ */
+
+#define TYPE_FILE 0x1
+#define TYPE_DIR  0x2
+#define TYPE_ANY  (TYPE_FILE | TYPE_DIR)

Please, rename these to something more specific like FS_ITER_ANY.

TYPE_ANY already is defined in fs/reiserfs/reiserfs_private.h:

fs/reiserfs/reiserfs_private.h:160:#define TYPE_ANY 15

Best regards

Heinrich

Quoted 29 lines

include/fat.h +25 -0

+
+typedef struct {
+	fsdata    *fsdata;        /* filesystem parameters */
+	unsigned   clust;         /* current cluster */
+	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 */
+
+	/* current iterator position values: */
+	dir_entry *dent;          /* current directory entry */
+	char       l_name[VFAT_MAXLEN_BYTES];    /* long (vfat) name */
+	char       s_name[14];    /* short 8.3 name */
+	char      *name;          /* l_name if there is one, else s_name */
+
+	/* storage for current cluster in memory: */
+	u8         block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
+} fat_itr;
+
+int fat_itr_root(fat_itr *itr, fsdata *fsdata);
+void fat_itr_child(fat_itr *itr, fat_itr *parent);
+void *next_cluster(fat_itr *itr);
+int fat_itr_next(fat_itr *itr);
+int fat_itr_isdir(fat_itr *itr);
+int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type);
+
 int file_fat_detectfs(void);
 int fat_exists(const char *filename);
 int fat_size(const char *filename, loff_t *size);

Quoted 126 lines · Heinrich Schuchardt

Quoted 112 lines · AKASHI Takahiro

Directory iterator was introduced in major re-work of read operation by Rob. We want to use it for write operation extensively as well. This patch makes relevant functions, as well as iterator defition, visible outside of fat.c.

Signed-off-by AKASHI Takahiro <[email protected]>

---
 fs/fat/fat.c  | 39 ++++++---------------------------------
 include/fat.h | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 33 deletions(-)

fs/fat/fat.c +6 -33

index fd6523c66b..0f82cbe1bd 100644
@@ -634,25 +634,6 @@ static int get_fs_info(fsdata *mydata)
  * For more complete example, see fat_itr_resolve()
  */
 
-typedef struct {
-	fsdata    *fsdata;        /* filesystem parameters */
-	unsigned   clust;         /* current cluster */
-	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 */
-
-	/* current iterator position values: */
-	dir_entry *dent;          /* current directory entry */
-	char       l_name[VFAT_MAXLEN_BYTES];    /* long (vfat) name */
-	char       s_name[14];    /* short 8.3 name */
-	char      *name;          /* l_name if there is one, else s_name */
-
-	/* storage for current cluster in memory: */
-	u8         block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
-} fat_itr;
-
-static int fat_itr_isdir(fat_itr *itr);
-
 /**
  * fat_itr_root() - initialize an iterator to start at the root
  * directory

@@ -661,7 +642,7 @@ static int fat_itr_isdir(fat_itr *itr);
  * @fsdata: filesystem data for the partition
  * @return 0 on success, else -errno
  */
-static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
+int fat_itr_root(fat_itr *itr, fsdata *fsdata)
 {
 	if (get_fs_info(fsdata))
 		return -ENXIO;

@@ -693,7 +674,7 @@ static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
  * @parent: the iterator pointing at a directory entry in the
  *    parent directory of the directory to iterate
  */
-static void fat_itr_child(fat_itr *itr, fat_itr *parent)
+void fat_itr_child(fat_itr *itr, fat_itr *parent)
 {
 	fsdata *mydata = parent->fsdata;  /* for silly macros */
 	unsigned clustnum = START(parent->dent);

@@ -713,7 +694,7 @@ static void fat_itr_child(fat_itr *itr, fat_itr *parent)
 	itr->last_cluster = 0;
 }
 
-static void *next_cluster(fat_itr *itr)
+void *next_cluster(fat_itr *itr)
 {
 	fsdata *mydata = itr->fsdata;  /* for silly macros */
 	int ret;

@@ -834,7 +815,7 @@ static dir_entry *extract_vfat_name(fat_itr *itr)
  * @return boolean, 1 if success or 0 if no more entries in the
  *    current directory
  */
-static int fat_itr_next(fat_itr *itr)
+int fat_itr_next(fat_itr *itr)
 {
 	dir_entry *dent;
 

@@ -879,19 +860,11 @@ static int fat_itr_next(fat_itr *itr)
  * @itr: the iterator
  * @return true if cursor is at a directory
  */
-static int fat_itr_isdir(fat_itr *itr)
+int fat_itr_isdir(fat_itr *itr)
 {
 	return !!(itr->dent->attr & ATTR_DIR);
 }
 
-/*
- * Helpers:
- */
-
-#define TYPE_FILE 0x1
-#define TYPE_DIR  0x2
-#define TYPE_ANY  (TYPE_FILE | TYPE_DIR)
-
 /**
  * fat_itr_resolve() - traverse directory structure to resolve the
  * requested path.

@@ -907,7 +880,7 @@ static int fat_itr_isdir(fat_itr *itr)
  * @type: bitmask of allowable file types
  * @return 0 on success or -errno
  */
-static int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
+int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
 {
 	const char *next;
 

include/fat.h +0 -0

index 0c88b59a4a..577e6b4592 100644

include/fat.h static inline u32 sect_to_clust(fsdata *fsdata, int sect) · line 196

Quoted 10 lines

include/fat.h +7 -0

@@ -187,6 +187,38 @@ static inline u32 sect_to_clust(fsdata *fsdata, int sect)
 	return (sect - fsdata->data_begin) / fsdata->clust_size;
 }
 
+/*
+ * Directory iterator
+ */
+
+#define TYPE_FILE 0x1
+#define TYPE_DIR  0x2
+#define TYPE_ANY  (TYPE_FILE | TYPE_DIR)

Please, rename these to something more specific like FS_ITER_ANY.

Quoted 3 lines

TYPE_ANY already is defined in fs/reiserfs/reiserfs_private.h:

fs/reiserfs/reiserfs_private.h:160:#define TYPE_ANY 15

Good catch though the definition above comes directly from Rob's original patch.

Since there is only one occurrence of TYPE_ANY in fs/fat, I'd rather expand it without introducing another definition.

Thanks,
-Takahiro AKASHI

Quoted 34 lines

Best regards

Heinrich

Quoted 29 lines

include/fat.h +25 -0

+
+typedef struct {
+	fsdata    *fsdata;        /* filesystem parameters */
+	unsigned   clust;         /* current cluster */
+	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 */
+
+	/* current iterator position values: */
+	dir_entry *dent;          /* current directory entry */
+	char       l_name[VFAT_MAXLEN_BYTES];    /* long (vfat) name */
+	char       s_name[14];    /* short 8.3 name */
+	char      *name;          /* l_name if there is one, else s_name */
+
+	/* storage for current cluster in memory: */
+	u8         block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
+} fat_itr;
+
+int fat_itr_root(fat_itr *itr, fsdata *fsdata);
+void fat_itr_child(fat_itr *itr, fat_itr *parent);
+void *next_cluster(fat_itr *itr);
+int fat_itr_next(fat_itr *itr);
+int fat_itr_isdir(fat_itr *itr);
+int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type);
+
 int file_fat_detectfs(void);
 int fat_exists(const char *filename);
 int fat_size(const char *filename, loff_t *size);

Directory iterator was introduced in major re-work of read operation by Rob. We want to use it for write operation extensively as well. This patch makes relevant functions, as well as iterator defition, visible outside of fat.c.

Signed-off-by AKASHI Takahiro <[email protected]>

---
 fs/fat/fat.c  | 39 ++++++---------------------------------
 include/fat.h | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 33 deletions(-)

fs/fat/fat.c +6 -33

index fd6523c66b..0f82cbe1bd 100644
@@ -634,25 +634,6 @@ static int get_fs_info(fsdata *mydata)
  * For more complete example, see fat_itr_resolve()
  */
 
-typedef struct {
-	fsdata    *fsdata;        /* filesystem parameters */
-	unsigned   clust;         /* current cluster */
-	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 */
-
-	/* current iterator position values: */
-	dir_entry *dent;          /* current directory entry */
-	char       l_name[VFAT_MAXLEN_BYTES];    /* long (vfat) name */
-	char       s_name[14];    /* short 8.3 name */
-	char      *name;          /* l_name if there is one, else s_name */
-
-	/* storage for current cluster in memory: */
-	u8         block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
-} fat_itr;
-
-static int fat_itr_isdir(fat_itr *itr);
-
 /**
  * fat_itr_root() - initialize an iterator to start at the root
  * directory

@@ -661,7 +642,7 @@ static int fat_itr_isdir(fat_itr *itr);
  * @fsdata: filesystem data for the partition
  * @return 0 on success, else -errno
  */
-static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
+int fat_itr_root(fat_itr *itr, fsdata *fsdata)
 {
 	if (get_fs_info(fsdata))
 		return -ENXIO;

@@ -693,7 +674,7 @@ static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
  * @parent: the iterator pointing at a directory entry in the
  *    parent directory of the directory to iterate
  */
-static void fat_itr_child(fat_itr *itr, fat_itr *parent)
+void fat_itr_child(fat_itr *itr, fat_itr *parent)
 {
 	fsdata *mydata = parent->fsdata;  /* for silly macros */
 	unsigned clustnum = START(parent->dent);

@@ -713,7 +694,7 @@ static void fat_itr_child(fat_itr *itr, fat_itr *parent)
 	itr->last_cluster = 0;
 }
 
-static void *next_cluster(fat_itr *itr)
+void *next_cluster(fat_itr *itr)
 {
 	fsdata *mydata = itr->fsdata;  /* for silly macros */
 	int ret;

@@ -834,7 +815,7 @@ static dir_entry *extract_vfat_name(fat_itr *itr)
  * @return boolean, 1 if success or 0 if no more entries in the
  *    current directory
  */
-static int fat_itr_next(fat_itr *itr)
+int fat_itr_next(fat_itr *itr)
 {
 	dir_entry *dent;
 

@@ -879,19 +860,11 @@ static int fat_itr_next(fat_itr *itr)
  * @itr: the iterator
  * @return true if cursor is at a directory
  */
-static int fat_itr_isdir(fat_itr *itr)
+int fat_itr_isdir(fat_itr *itr)
 {
 	return !!(itr->dent->attr & ATTR_DIR);
 }
 
-/*
- * Helpers:
- */
-
-#define TYPE_FILE 0x1
-#define TYPE_DIR  0x2
-#define TYPE_ANY  (TYPE_FILE | TYPE_DIR)
-
 /**
  * fat_itr_resolve() - traverse directory structure to resolve the
  * requested path.

@@ -907,7 +880,7 @@ static int fat_itr_isdir(fat_itr *itr)
  * @type: bitmask of allowable file types
  * @return 0 on success or -errno
  */
-static int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
+int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
 {
 	const char *next;
 

include/fat.h +13 -0

index 0c88b59a4a..577e6b4592 100644
@@ -187,6 +187,38 @@ static inline u32 sect_to_clust(fsdata *fsdata, int sect)
 	return (sect - fsdata->data_begin) / fsdata->clust_size;
 }
 
+/*
+ * Directory iterator
+ */
+
+#define TYPE_FILE 0x1
+#define TYPE_DIR  0x2
+#define TYPE_ANY  (TYPE_FILE | TYPE_DIR)
+
+typedef struct {
+	fsdata    *fsdata;        /* filesystem parameters */
+	unsigned   clust;         /* current cluster */
+	int        last_cluster;  /* set once we've read last cluster */
+	int        is_root;       /* is iterator at root directory */

include/fat.h +9 -0

+} fat_itr;
+
+int fat_itr_root(fat_itr *itr, fsdata *fsdata);
+void fat_itr_child(fat_itr *itr, fat_itr *parent);
+void *next_cluster(fat_itr *itr);
+int fat_itr_next(fat_itr *itr);
+int fat_itr_isdir(fat_itr *itr);
+int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type);
+
 int file_fat_detectfs(void);
 int fat_exists(const char *filename);
 int fat_size(const char *filename, loff_t *size);

Quoted 128 lines · AKASHI Takahiro

Directory iterator was introduced in major re-work of read operation by Rob. We want to use it for write operation extensively as well. This patch makes relevant functions, as well as iterator defition, visible outside of fat.c.

Signed-off-by AKASHI Takahiro <[email protected]>

---
 fs/fat/fat.c  | 39 ++++++---------------------------------
 include/fat.h | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 33 deletions(-)

fs/fat/fat.c +6 -33

index fd6523c66b..0f82cbe1bd 100644
@@ -634,25 +634,6 @@ static int get_fs_info(fsdata *mydata)
  * For more complete example, see fat_itr_resolve()
  */
 
-typedef struct {
-	fsdata    *fsdata;        /* filesystem parameters */
-	unsigned   clust;         /* current cluster */
-	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 */
-
-	/* current iterator position values: */
-	dir_entry *dent;          /* current directory entry */
-	char       l_name[VFAT_MAXLEN_BYTES];    /* long (vfat) name */
-	char       s_name[14];    /* short 8.3 name */
-	char      *name;          /* l_name if there is one, else s_name */
-
-	/* storage for current cluster in memory: */
-	u8         block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
-} fat_itr;
-
-static int fat_itr_isdir(fat_itr *itr);
-
 /**
  * fat_itr_root() - initialize an iterator to start at the root
  * directory

@@ -661,7 +642,7 @@ static int fat_itr_isdir(fat_itr *itr);
  * @fsdata: filesystem data for the partition
  * @return 0 on success, else -errno
  */
-static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
+int fat_itr_root(fat_itr *itr, fsdata *fsdata)
 {
 	if (get_fs_info(fsdata))
 		return -ENXIO;

@@ -693,7 +674,7 @@ static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
  * @parent: the iterator pointing at a directory entry in the
  *    parent directory of the directory to iterate
  */
-static void fat_itr_child(fat_itr *itr, fat_itr *parent)
+void fat_itr_child(fat_itr *itr, fat_itr *parent)
 {
 	fsdata *mydata = parent->fsdata;  /* for silly macros */
 	unsigned clustnum = START(parent->dent);

@@ -713,7 +694,7 @@ static void fat_itr_child(fat_itr *itr, fat_itr *parent)
 	itr->last_cluster = 0;
 }
 
-static void *next_cluster(fat_itr *itr)
+void *next_cluster(fat_itr *itr)
 {
 	fsdata *mydata = itr->fsdata;  /* for silly macros */
 	int ret;

@@ -834,7 +815,7 @@ static dir_entry *extract_vfat_name(fat_itr *itr)
  * @return boolean, 1 if success or 0 if no more entries in the
  *    current directory
  */
-static int fat_itr_next(fat_itr *itr)
+int fat_itr_next(fat_itr *itr)
 {
 	dir_entry *dent;
 

@@ -879,19 +860,11 @@ static int fat_itr_next(fat_itr *itr)
  * @itr: the iterator
  * @return true if cursor is at a directory
  */
-static int fat_itr_isdir(fat_itr *itr)
+int fat_itr_isdir(fat_itr *itr)
 {
 	return !!(itr->dent->attr & ATTR_DIR);
 }
 
-/*
- * Helpers:
- */
-
-#define TYPE_FILE 0x1
-#define TYPE_DIR  0x2
-#define TYPE_ANY  (TYPE_FILE | TYPE_DIR)
-
 /**
  * fat_itr_resolve() - traverse directory structure to resolve the
  * requested path.

@@ -907,7 +880,7 @@ static int fat_itr_isdir(fat_itr *itr)
  * @type: bitmask of allowable file types
  * @return 0 on success or -errno
  */
-static int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
+int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
 {
 	const char *next;
 

include/fat.h +13 -0

index 0c88b59a4a..577e6b4592 100644
@@ -187,6 +187,38 @@ static inline u32 sect_to_clust(fsdata *fsdata, int sect)
 	return (sect - fsdata->data_begin) / fsdata->clust_size;
 }
 
+/*
+ * Directory iterator
+ */
+
+#define TYPE_FILE 0x1
+#define TYPE_DIR  0x2
+#define TYPE_ANY  (TYPE_FILE | TYPE_DIR)
+
+typedef struct {
+	fsdata    *fsdata;        /* filesystem parameters */
+	unsigned   clust;         /* current cluster */
+	int        last_cluster;  /* set once we've read last cluster */
+	int        is_root;       /* is iterator at root directory */

include/fat.h static inline u32 sect_to_clust(fsdata *fsdata, int sect) · line 212

Quoted 10 lines

include/fat.h +10 -0

+	int        remaining;     /* remaining dent's in current cluster */
+
+	/* current iterator position values: */
+	dir_entry *dent;          /* current directory entry */
+	char       l_name[VFAT_MAXLEN_BYTES];    /* long (vfat) name */
+	char       s_name[14];    /* short 8.3 name */
+	char      *name;          /* l_name if there is one, else s_name */
+
+	/* storage for current cluster in memory: */
+	u8         block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);

If CONFIG_FAT is not set, MAX_CLUSTSIZE is empty. And you get a build error:

CC fs/fs.o
In file included from fs/fs.c:12:0:
include/fat.h:20:23: error: ‘CONFIG_FS_FAT_MAX_CLUSTSIZE’ undeclared here (not in a function); did you mean ‘CONFIG_SYS_MAX_FLASH_SECT’?

 #define MAX_CLUSTSIZE CONFIG_FS_FAT_MAX_CLUSTSIZE
                       ^
include/fat.h:214:19: note: in expansion of macro ‘MAX_CLUSTSIZE’
  u8         block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
                   ^~~~~~~~~~~~~

make[1]: *** [scripts/Makefile.build:279: fs/fs.o] Error 1

We should not assume that every board uses FAT.

Best regards

Heinrich

Quoted 13 lines

include/fat.h +9 -0

+} fat_itr;
+
+int fat_itr_root(fat_itr *itr, fsdata *fsdata);
+void fat_itr_child(fat_itr *itr, fat_itr *parent);
+void *next_cluster(fat_itr *itr);
+int fat_itr_next(fat_itr *itr);
+int fat_itr_isdir(fat_itr *itr);
+int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type);
+
 int file_fat_detectfs(void);
 int fat_exists(const char *filename);
 int fat_size(const char *filename, loff_t *size);

FAT file system's long file name support is a bit complicated and has some restrictions on its naming. We should be careful about it especially for write as it may easily end up with wrong file system.

normalize_longname() check for the rules and normalize a file name if necessary. Please note, however, that this function is yet to be extended to fully comply with the standard.

Signed-off-by AKASHI Takahiro <[email protected]>

---
 fs/fat/fat_write.c | 52 +++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 44 insertions(+), 8 deletions(-)

fs/fat/fat_write.c +0 -0

index 3b77557b3e..6c715a70f4 100644

fs/fat/fat_write.c +12 -0

+	char c;
+	int name_len;
+
+	/* Check that the filename is valid */
+	for (p = filename; p < filename + strlen(filename); p++) {
+		c = *p;
+
+		if (('0' <= c) && (c <= '9'))
+			continue;
+		if (('A' <= c) && (c <= 'Z'))
+			continue;
+		if (('a' <= c) && (c <= 'z'))

It would be good that FAT write function return error code instead of just returning -1 as fat_read_file() does.
This patch attempts to address this issue although it is 'best effort (or estimate)' for now.

Signed-off-by AKASHI Takahiro <[email protected]>

---
 fs/fat/fat_write.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

fs/fat/fat_write.c +15 -4

index 6c715a70f4..1e4f5af910 100644
@@ -956,7 +956,7 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 
 	if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
 		debug("error: reading boot sector\n");
-		return -1;
+		return -EIO;
 	}
 
 	total_sector = bs.total_sect;

@@ -997,7 +997,7 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 	mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
 	if (mydata->fatbuf == NULL) {
 		debug("Error: allocating memory\n");
-		return -1;
+		return -ENOMEM;
 	}
 
 	if (disk_read(cursect,

@@ -1005,6 +1005,7 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 		(mydata->clust_size) :
 		PREFETCH_BLOCKS, do_fat_read_at_block) < 0) {
 		debug("Error: reading rootdir block\n");
+		ret = -EIO;
 		goto exit;
 	}
 	dentptr = (dir_entry *) do_fat_read_at_block;

@@ -1029,6 +1030,7 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 							size);
 				if (ret) {
 					printf("Error: %llu overflow\n", size);
+					ret = -ENOSPC;
 					goto exit;
 				}
 			}

@@ -1036,6 +1038,7 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 			ret = clear_fatent(mydata, start_cluster);
 			if (ret) {
 				printf("Error: clearing FAT entries\n");
+				ret = -EIO;
 				goto exit;
 			}
 

@@ -1045,12 +1048,14 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 			ret = start_cluster = find_empty_cluster(mydata);
 			if (ret < 0) {
 				printf("Error: finding empty cluster\n");
+				ret = -ENOSPC;
 				goto exit;
 			}
 
 			ret = check_overflow(mydata, start_cluster, size);
 			if (ret) {
 				printf("Error: %llu overflow\n", size);
+				ret = -ENOSPC;
 				goto exit;
 			}
 

@@ -1065,12 +1070,14 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 			ret = start_cluster = find_empty_cluster(mydata);
 			if (ret < 0) {
 				printf("Error: finding empty cluster\n");
+				ret = -ENOSPC;
 				goto exit;
 			}
 
 			ret = check_overflow(mydata, start_cluster, size);
 			if (ret) {
 				printf("Error: %llu overflow\n", size);
+				ret = -ENOSPC;
 				goto exit;
 			}
 		} else {

@@ -1087,6 +1094,7 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 	ret = set_contents(mydata, retdent, buffer, size, actwrite);
 	if (ret < 0) {
 		printf("Error: writing contents\n");
+		ret = -EIO;
 		goto exit;
 	}
 	debug("attempt to write 0x%llx bytes\n", *actwrite);

@@ -1095,14 +1103,17 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 	ret = flush_dirty_fat_buffer(mydata);
 	if (ret) {
 		printf("Error: flush fat buffer\n");
+		ret = -EIO;
 		goto exit;
 	}
 
 	/* Write directory table to device */
 	ret = set_cluster(mydata, dir_curclust, get_dentfromdir_block,
 			mydata->clust_size * mydata->sect_size);
-	if (ret)
+	if (ret) {
 		printf("Error: writing directory entry\n");
+		ret = -EIO;
+	}
 
 exit:
 	free(mydata->fatbuf);

@@ -1114,7 +1125,7 @@ int file_fat_write(const char *filename, void *buffer, loff_t offset,
 {
 	if (offset != 0) {
 		printf("Error: non zero offset is currently not supported.\n");
-		return -1;
+		return -EINVAL;
 	}
 
 	printf("writing %s\n", filename);

Quoted 6 lines · AKASHI Takahiro

It would be good that FAT write function return error code instead of just returning -1 as fat_read_file() does.
This patch attempts to address this issue although it is 'best effort (or estimate)' for now.

Signed-off-by AKASHI Takahiro <[email protected]>

Some of the error message are written with debug() others with printf().

Shouldn't we switch everything to debug() so that the EFI console is not messed up?

Best regards

Heinrich

Quoted 117 lines

---
 fs/fat/fat_write.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

fs/fat/fat_write.c +15 -4

index 6c715a70f4..1e4f5af910 100644
@@ -956,7 +956,7 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 
 	if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
 		debug("error: reading boot sector\n");
-		return -1;
+		return -EIO;
 	}
 
 	total_sector = bs.total_sect;

@@ -997,7 +997,7 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 	mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
 	if (mydata->fatbuf == NULL) {
 		debug("Error: allocating memory\n");
-		return -1;
+		return -ENOMEM;
 	}
 
 	if (disk_read(cursect,

@@ -1005,6 +1005,7 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 		(mydata->clust_size) :
 		PREFETCH_BLOCKS, do_fat_read_at_block) < 0) {
 		debug("Error: reading rootdir block\n");
+		ret = -EIO;
 		goto exit;
 	}
 	dentptr = (dir_entry *) do_fat_read_at_block;

@@ -1029,6 +1030,7 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 							size);
 				if (ret) {
 					printf("Error: %llu overflow\n", size);
+					ret = -ENOSPC;
 					goto exit;
 				}
 			}

@@ -1036,6 +1038,7 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 			ret = clear_fatent(mydata, start_cluster);
 			if (ret) {
 				printf("Error: clearing FAT entries\n");
+				ret = -EIO;
 				goto exit;
 			}
 

@@ -1045,12 +1048,14 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 			ret = start_cluster = find_empty_cluster(mydata);
 			if (ret < 0) {
 				printf("Error: finding empty cluster\n");
+				ret = -ENOSPC;
 				goto exit;
 			}
 
 			ret = check_overflow(mydata, start_cluster, size);
 			if (ret) {
 				printf("Error: %llu overflow\n", size);
+				ret = -ENOSPC;
 				goto exit;
 			}
 

@@ -1065,12 +1070,14 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 			ret = start_cluster = find_empty_cluster(mydata);
 			if (ret < 0) {
 				printf("Error: finding empty cluster\n");
+				ret = -ENOSPC;
 				goto exit;
 			}
 
 			ret = check_overflow(mydata, start_cluster, size);
 			if (ret) {
 				printf("Error: %llu overflow\n", size);
+				ret = -ENOSPC;
 				goto exit;
 			}
 		} else {

@@ -1087,6 +1094,7 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 	ret = set_contents(mydata, retdent, buffer, size, actwrite);
 	if (ret < 0) {
 		printf("Error: writing contents\n");
+		ret = -EIO;
 		goto exit;
 	}
 	debug("attempt to write 0x%llx bytes\n", *actwrite);

@@ -1095,14 +1103,17 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,
 	ret = flush_dirty_fat_buffer(mydata);
 	if (ret) {
 		printf("Error: flush fat buffer\n");
+		ret = -EIO;
 		goto exit;
 	}
 
 	/* Write directory table to device */
 	ret = set_cluster(mydata, dir_curclust, get_dentfromdir_block,
 			mydata->clust_size * mydata->sect_size);
-	if (ret)
+	if (ret) {
 		printf("Error: writing directory entry\n");
+		ret = -EIO;
+	}
 
 exit:
 	free(mydata->fatbuf);

@@ -1114,7 +1125,7 @@ int file_fat_write(const char *filename, void *buffer, loff_t offset,
 {
 	if (offset != 0) {
 		printf("Error: non zero offset is currently not supported.\n");
-		return -1;
+		return -EINVAL;
 	}
 
 	printf("writing %s\n", filename);

In this patch, all the necessary code for allowing for a file offset at write is implemented. What plays a major roll here is get_set_cluster(), which, in contrast to its counterpart, set_cluster(), only operates on already-allocated clusters, overwriting with data.

So, with a file offset specified, set_contents() seeks and writes data with set_get_cluster() until the end of a file, and, once it reaches there, continues writing with set_cluster() for the rest.

Please note that a file will be trimmed as a result of write operation if write ends before reaching file's end. This is an intended behavior in order to maitain compatibility with the current interface.

Signed-off-by AKASHI Takahiro <[email protected]>

---
 fs/fat/fat_write.c | 287 ++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 272 insertions(+), 15 deletions(-)

fs/fat/fat_write.c +272 -15

index 3a9c53e253..cc45a33876 100644
@@ -450,6 +450,120 @@ set_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer,
 	return 0;
 }
 
+static __u8 tmpbuf_cluster[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
+
+/*
+ * Read and modify data on existing and consecutive cluster blocks
+ */
+static int
+get_set_cluster(fsdata *mydata, __u32 clustnum, loff_t pos, __u8 *buffer,
+		loff_t size, loff_t *gotsize)
+{
+	unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
+	__u32 startsect;
+	loff_t wsize;
+	int clustcount, i, ret;
+
+	*gotsize = 0;
+	if (!size)
+		return 0;
+
+	assert(pos < bytesperclust);
+	startsect = clust_to_sect(mydata, clustnum);
+
+	debug("clustnum: %d, startsect: %d, pos: %lld\n", clustnum, startsect,
+									pos);
+
+	/* partial write at beginning */
+	if (pos) {
+		wsize = min(bytesperclust - pos, size);
+		ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
+		if (ret != mydata->clust_size) {
+			debug("Error reading data (got %d)\n", ret);
+			return -1;
+		}
+
+		memcpy(tmpbuf_cluster + pos, buffer, wsize);
+		ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
+		if (ret != mydata->clust_size) {
+			debug("Error writing data (got %d)\n", ret);
+			return -1;
+		}
+
+		size -= wsize;
+		buffer += wsize;
+		*gotsize += wsize;
+
+		startsect += mydata->clust_size;
+
+		if (!size)
+			return 0;
+	}
+
+	/* full-cluster write */
+	if (size >= bytesperclust) {
+		clustcount = lldiv(size, bytesperclust);
+
+		if (!((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1))) {
+			wsize = clustcount * bytesperclust;
+			ret = disk_write(startsect,
+					clustcount * mydata->clust_size,
+					buffer);
+			if (ret != clustcount * mydata->clust_size) {
+				debug("Error writing data (got %d)\n", ret);
+				return -1;
+			}
+
+			size -= wsize;
+			buffer += wsize;
+			*gotsize += wsize;
+
+			startsect += clustcount * mydata->clust_size;
+		} else {
+			for (i = 0; i < clustcount; i++) {
+				memcpy(tmpbuf_cluster, buffer, bytesperclust);
+				ret = disk_write(startsect, mydata->clust_size,
+								tmpbuf_cluster);
+				if (ret != mydata->clust_size) {
+					debug("Error writing data (got %d)\n",
+									ret);
+					return -1;
+				}
+
+				size -= bytesperclust;
+				buffer += bytesperclust;
+				*gotsize += bytesperclust;
+
+				startsect += mydata->clust_size;
+			}
+		}
+	}
+
+	/* partial write at end */
+	if (size) {
+		wsize = size;
+		ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
+		if (ret != mydata->clust_size) {
+			debug("Error reading data (got %d)\n", ret);
+			return -1;
+		}
+		memcpy(tmpbuf_cluster, buffer, wsize);
+		ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
+		if (ret != mydata->clust_size) {
+			debug("Error writing data (got %d)\n", ret);
+			return -1;
+		}
+
+		size -= wsize;
+		buffer += wsize;
+		*gotsize += wsize;
+	}
+
+	assert(!size);
+
+	return 0;
+}
+
 /*
  * Find the first empty cluster
  */

@@ -579,26 +693,158 @@ set_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos, __u8 *buffer,
 	unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 	__u32 curclust = START(dentptr);
 	__u32 endclust = 0, newclust = 0;
-	loff_t actsize;
+	loff_t cur_pos, offset, actsize, wsize;
 
 	*gotsize = 0;
-	filesize = maxsize;
+	filesize = pos + maxsize;
 
 	debug("%llu bytes\n", filesize);
 
-	if (curclust) {
-		/*
-		 * release already-allocated clusters anyway
-		 */
-		if (clear_fatent(mydata, curclust)) {
-			printf("Error: clearing FAT entries\n");
+	if (!filesize) {
+		if (!curclust)
+			return 0;
+		if (!CHECK_CLUST(curclust, mydata->fatsize) ||
+		    IS_LAST_CLUST(curclust, mydata->fatsize)) {
+			clear_fatent(mydata, curclust);
+			set_start_cluster(mydata, dentptr, 0);
+			return 0;
+		}
+		debug("curclust: 0x%x\n", curclust);
+		debug("Invalid FAT entry\n");
+		return -1;
+	}
+
+	if (!curclust) {
+		assert(pos == 0);
+		goto set_clusters;
+	}
+
+	/* go to cluster at pos */
+	cur_pos = bytesperclust;
+	while (1) {
+		if (pos <= cur_pos)
+			break;
+		if (IS_LAST_CLUST(curclust, mydata->fatsize))
+			break;
+
+		newclust = get_fatent(mydata, curclust);
+		if (!IS_LAST_CLUST(newclust, mydata->fatsize) &&
+		    CHECK_CLUST(newclust, mydata->fatsize)) {
+			debug("curclust: 0x%x\n", curclust);
+			debug("Invalid FAT entry\n");
 			return -1;
 		}
+
+		cur_pos += bytesperclust;
+		curclust = newclust;
+	}
+	if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
+		assert(pos == cur_pos);
+		goto set_clusters;
 	}
 
-	curclust = find_empty_cluster(mydata);
-	set_start_cluster(mydata, dentptr, curclust);
+	assert(pos < cur_pos);
+	cur_pos -= bytesperclust;
 
+	/* overwrite */
+	assert(IS_LAST_CLUST(curclust, mydata->fatsize) ||
+	       !CHECK_CLUST(curclust, mydata->fatsize));
+
+	while (1) {
+		/* search for allocated consecutive clusters */
+		actsize = bytesperclust;
+		endclust = curclust;
+		while (1) {
+			if (filesize <= (cur_pos + actsize))
+				break;
+
+			newclust = get_fatent(mydata, endclust);
+
+			if (IS_LAST_CLUST(newclust, mydata->fatsize))
+				break;
+			if (CHECK_CLUST(newclust, mydata->fatsize)) {
+				debug("curclust: 0x%x\n", curclust);
+				debug("Invalid FAT entry\n");
+				return -1;
+			}
+
+			actsize += bytesperclust;
+			endclust = newclust;
+		}
+
+		/* overwrite to <curclust..endclust> */
+		if (pos < cur_pos)
+			offset = 0;
+		else
+			offset = pos - cur_pos;
+		wsize = min(cur_pos + actsize, filesize) - pos;
+		if (get_set_cluster(mydata, curclust, offset, buffer, wsize,
+								&actsize)) {
+			printf("Error get-and-setting cluster\n");
+			return -1;
+		}
+		buffer += wsize;
+		*gotsize += wsize;
+		cur_pos += offset + wsize;
+
+		if (filesize <= cur_pos)
+			break;
+
+		/* CHECK: newclust = get_fatent(mydata, endclust); */
+
+		if (IS_LAST_CLUST(newclust, mydata->fatsize))
+			/* no more clusters */
+			break;
+
+		curclust = newclust;
+	}
+
+	if (filesize <= cur_pos) {
+		/* no more write */
+		newclust = get_fatent(mydata, endclust);
+		if (!IS_LAST_CLUST(newclust, mydata->fatsize)) {
+			/* truncate the rest */
+			clear_fatent(mydata, newclust);
+
+			/* Mark end of file in FAT */
+			if (mydata->fatsize == 12)
+				newclust = 0xfff;
+			else if (mydata->fatsize == 16)
+				newclust = 0xffff;
+			else if (mydata->fatsize == 32)
+				newclust = 0xfffffff;
+			set_fatent_value(mydata, endclust, newclust);
+		}
+
+		return 0;
+	}
+
+	curclust = endclust;
+	filesize -= cur_pos;
+	assert(!(cur_pos % bytesperclust));
+
+set_clusters:
+	/* allocate and write */
+	assert(!pos);
+
+	/* Assure that curclust is valid */
+	if (!curclust) {
+		curclust = find_empty_cluster(mydata);
+		set_start_cluster(mydata, dentptr, curclust);
+	} else {
+		newclust = get_fatent(mydata, curclust);
+
+		if (IS_LAST_CLUST(newclust, mydata->fatsize)) {
+			newclust = determine_fatent(mydata, curclust);
+			set_fatent_value(mydata, curclust, newclust);
+			curclust = newclust;
+		} else {
+			debug("error: something wrong\n");
+			return -1;
+		}
+	}
+
+	/* TODO: already partially written */
 	if (check_overflow(mydata, curclust, filesize)) {
 		printf("Error: no space left: %llu\n", filesize);
 		return -1;

@@ -852,6 +1098,16 @@ int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
 			goto exit;
 		}
 
+		/* A file exists */
+		if (pos == -1)
+			/* Append to the end */
+			pos = FAT2CPU32(retdent->size);
+		if (pos > retdent->size) {
+			/* No hole allowed */
+			ret = -EINVAL;
+			goto exit;
+		}
+
 		/* Update file size in a directory entry */
 		retdent->size = cpu_to_le32(pos + size);
 	} else {

@@ -872,6 +1128,12 @@ int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
 			goto exit;
 		}
 
+		if (pos) {
+			/* No hole allowed */
+			ret = -EINVAL;
+			goto exit;
+		}
+
 		memset(itr->dent, 0, sizeof(*itr->dent));
 
 		/* Set short name to set alias checksum field in dir_slot */

@@ -921,10 +1183,5 @@ exit:
 int file_fat_write(const char *filename, void *buffer, loff_t offset,
 		   loff_t maxsize, loff_t *actwrite)
 {
-	if (offset != 0) {
-		printf("Error: non zero offset is currently not supported.\n");
-		return -EINVAL;
-	}
-
 	return file_fat_write_at(filename, offset, buffer, maxsize, actwrite);
 }

Quoted 9 lines · AKASHI Takahiro

In this patch, all the necessary code for allowing for a file offset at write is implemented. What plays a major roll here is get_set_cluster(), which, in contrast to its counterpart, set_cluster(), only operates on already-allocated clusters, overwriting with data.

So, with a file offset specified, set_contents() seeks and writes data with set_get_cluster() until the end of a file, and, once it reaches there, continues writing with set_cluster() for the rest.

Quoted 3 lines

Please note that a file will be trimmed as a result of write operation if write ends before reaching file's end. This is an intended behavior in order to maitain compatibility with the current interface.

This does not match the EFI spec.

Quoted 2 lines

Signed-off-by AKASHI Takahiro <[email protected]>

When testing I observed that I could not write at an offset larger than the file size. This does not match the EFI spec:

EFI_FILE_PROTOCOL.SetPosition():
seeking past the end of the file is allowed (a subsequent write would grow the file).

Best regards

Heinrich

Quoted 340 lines

---
 fs/fat/fat_write.c | 287 ++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 272 insertions(+), 15 deletions(-)

fs/fat/fat_write.c +272 -15

index 3a9c53e253..cc45a33876 100644
@@ -450,6 +450,120 @@ set_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer,
 	return 0;
 }
 
+static __u8 tmpbuf_cluster[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
+
+/*
+ * Read and modify data on existing and consecutive cluster blocks
+ */
+static int
+get_set_cluster(fsdata *mydata, __u32 clustnum, loff_t pos, __u8 *buffer,
+		loff_t size, loff_t *gotsize)
+{
+	unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
+	__u32 startsect;
+	loff_t wsize;
+	int clustcount, i, ret;
+
+	*gotsize = 0;
+	if (!size)
+		return 0;
+
+	assert(pos < bytesperclust);
+	startsect = clust_to_sect(mydata, clustnum);
+
+	debug("clustnum: %d, startsect: %d, pos: %lld\n", clustnum, startsect,
+									pos);
+
+	/* partial write at beginning */
+	if (pos) {
+		wsize = min(bytesperclust - pos, size);
+		ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
+		if (ret != mydata->clust_size) {
+			debug("Error reading data (got %d)\n", ret);
+			return -1;
+		}
+
+		memcpy(tmpbuf_cluster + pos, buffer, wsize);
+		ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
+		if (ret != mydata->clust_size) {
+			debug("Error writing data (got %d)\n", ret);
+			return -1;
+		}
+
+		size -= wsize;
+		buffer += wsize;
+		*gotsize += wsize;
+
+		startsect += mydata->clust_size;
+
+		if (!size)
+			return 0;
+	}
+
+	/* full-cluster write */
+	if (size >= bytesperclust) {
+		clustcount = lldiv(size, bytesperclust);
+
+		if (!((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1))) {
+			wsize = clustcount * bytesperclust;
+			ret = disk_write(startsect,
+					clustcount * mydata->clust_size,
+					buffer);
+			if (ret != clustcount * mydata->clust_size) {
+				debug("Error writing data (got %d)\n", ret);
+				return -1;
+			}
+
+			size -= wsize;
+			buffer += wsize;
+			*gotsize += wsize;
+
+			startsect += clustcount * mydata->clust_size;
+		} else {
+			for (i = 0; i < clustcount; i++) {
+				memcpy(tmpbuf_cluster, buffer, bytesperclust);
+				ret = disk_write(startsect, mydata->clust_size,
+								tmpbuf_cluster);
+				if (ret != mydata->clust_size) {
+					debug("Error writing data (got %d)\n",
+									ret);
+					return -1;
+				}
+
+				size -= bytesperclust;
+				buffer += bytesperclust;
+				*gotsize += bytesperclust;
+
+				startsect += mydata->clust_size;
+			}
+		}
+	}
+
+	/* partial write at end */
+	if (size) {
+		wsize = size;
+		ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
+		if (ret != mydata->clust_size) {
+			debug("Error reading data (got %d)\n", ret);
+			return -1;
+		}
+		memcpy(tmpbuf_cluster, buffer, wsize);
+		ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
+		if (ret != mydata->clust_size) {
+			debug("Error writing data (got %d)\n", ret);
+			return -1;
+		}
+
+		size -= wsize;
+		buffer += wsize;
+		*gotsize += wsize;
+	}
+
+	assert(!size);
+
+	return 0;
+}
+
 /*
  * Find the first empty cluster
  */

@@ -579,26 +693,158 @@ set_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos, __u8 *buffer,
 	unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
 	__u32 curclust = START(dentptr);
 	__u32 endclust = 0, newclust = 0;
-	loff_t actsize;
+	loff_t cur_pos, offset, actsize, wsize;
 
 	*gotsize = 0;
-	filesize = maxsize;
+	filesize = pos + maxsize;
 
 	debug("%llu bytes\n", filesize);
 
-	if (curclust) {
-		/*
-		 * release already-allocated clusters anyway
-		 */
-		if (clear_fatent(mydata, curclust)) {
-			printf("Error: clearing FAT entries\n");
+	if (!filesize) {
+		if (!curclust)
+			return 0;
+		if (!CHECK_CLUST(curclust, mydata->fatsize) ||
+		    IS_LAST_CLUST(curclust, mydata->fatsize)) {
+			clear_fatent(mydata, curclust);
+			set_start_cluster(mydata, dentptr, 0);
+			return 0;
+		}
+		debug("curclust: 0x%x\n", curclust);
+		debug("Invalid FAT entry\n");
+		return -1;
+	}
+
+	if (!curclust) {
+		assert(pos == 0);
+		goto set_clusters;
+	}
+
+	/* go to cluster at pos */
+	cur_pos = bytesperclust;
+	while (1) {
+		if (pos <= cur_pos)
+			break;
+		if (IS_LAST_CLUST(curclust, mydata->fatsize))
+			break;
+
+		newclust = get_fatent(mydata, curclust);
+		if (!IS_LAST_CLUST(newclust, mydata->fatsize) &&
+		    CHECK_CLUST(newclust, mydata->fatsize)) {
+			debug("curclust: 0x%x\n", curclust);
+			debug("Invalid FAT entry\n");
 			return -1;
 		}
+
+		cur_pos += bytesperclust;
+		curclust = newclust;
+	}
+	if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
+		assert(pos == cur_pos);
+		goto set_clusters;
 	}
 
-	curclust = find_empty_cluster(mydata);
-	set_start_cluster(mydata, dentptr, curclust);
+	assert(pos < cur_pos);
+	cur_pos -= bytesperclust;
 
+	/* overwrite */
+	assert(IS_LAST_CLUST(curclust, mydata->fatsize) ||
+	       !CHECK_CLUST(curclust, mydata->fatsize));
+
+	while (1) {
+		/* search for allocated consecutive clusters */
+		actsize = bytesperclust;
+		endclust = curclust;
+		while (1) {
+			if (filesize <= (cur_pos + actsize))
+				break;
+
+			newclust = get_fatent(mydata, endclust);
+
+			if (IS_LAST_CLUST(newclust, mydata->fatsize))
+				break;
+			if (CHECK_CLUST(newclust, mydata->fatsize)) {
+				debug("curclust: 0x%x\n", curclust);
+				debug("Invalid FAT entry\n");
+				return -1;
+			}
+
+			actsize += bytesperclust;
+			endclust = newclust;
+		}
+
+		/* overwrite to <curclust..endclust> */
+		if (pos < cur_pos)
+			offset = 0;
+		else
+			offset = pos - cur_pos;
+		wsize = min(cur_pos + actsize, filesize) - pos;
+		if (get_set_cluster(mydata, curclust, offset, buffer, wsize,
+								&actsize)) {
+			printf("Error get-and-setting cluster\n");
+			return -1;
+		}
+		buffer += wsize;
+		*gotsize += wsize;
+		cur_pos += offset + wsize;
+
+		if (filesize <= cur_pos)
+			break;
+
+		/* CHECK: newclust = get_fatent(mydata, endclust); */
+
+		if (IS_LAST_CLUST(newclust, mydata->fatsize))
+			/* no more clusters */
+			break;
+
+		curclust = newclust;
+	}
+
+	if (filesize <= cur_pos) {
+		/* no more write */
+		newclust = get_fatent(mydata, endclust);
+		if (!IS_LAST_CLUST(newclust, mydata->fatsize)) {
+			/* truncate the rest */
+			clear_fatent(mydata, newclust);
+
+			/* Mark end of file in FAT */
+			if (mydata->fatsize == 12)
+				newclust = 0xfff;
+			else if (mydata->fatsize == 16)
+				newclust = 0xffff;
+			else if (mydata->fatsize == 32)
+				newclust = 0xfffffff;
+			set_fatent_value(mydata, endclust, newclust);
+		}
+
+		return 0;
+	}
+
+	curclust = endclust;
+	filesize -= cur_pos;
+	assert(!(cur_pos % bytesperclust));
+
+set_clusters:
+	/* allocate and write */
+	assert(!pos);
+
+	/* Assure that curclust is valid */
+	if (!curclust) {
+		curclust = find_empty_cluster(mydata);
+		set_start_cluster(mydata, dentptr, curclust);
+	} else {
+		newclust = get_fatent(mydata, curclust);
+
+		if (IS_LAST_CLUST(newclust, mydata->fatsize)) {
+			newclust = determine_fatent(mydata, curclust);
+			set_fatent_value(mydata, curclust, newclust);
+			curclust = newclust;
+		} else {
+			debug("error: something wrong\n");
+			return -1;
+		}
+	}
+
+	/* TODO: already partially written */
 	if (check_overflow(mydata, curclust, filesize)) {
 		printf("Error: no space left: %llu\n", filesize);
 		return -1;

@@ -852,6 +1098,16 @@ int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
 			goto exit;
 		}
 
+		/* A file exists */
+		if (pos == -1)
+			/* Append to the end */
+			pos = FAT2CPU32(retdent->size);
+		if (pos > retdent->size) {
+			/* No hole allowed */
+			ret = -EINVAL;
+			goto exit;
+		}
+
 		/* Update file size in a directory entry */
 		retdent->size = cpu_to_le32(pos + size);
 	} else {

@@ -872,6 +1128,12 @@ int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
 			goto exit;
 		}
 
+		if (pos) {
+			/* No hole allowed */
+			ret = -EINVAL;
+			goto exit;
+		}
+
 		memset(itr->dent, 0, sizeof(*itr->dent));
 
 		/* Set short name to set alias checksum field in dir_slot */

@@ -921,10 +1183,5 @@ exit:
 int file_fat_write(const char *filename, void *buffer, loff_t offset,
 		   loff_t maxsize, loff_t *actwrite)
 {
-	if (offset != 0) {
-		printf("Error: non zero offset is currently not supported.\n");
-		return -EINVAL;
-	}
-
 	return file_fat_write_at(filename, offset, buffer, maxsize, actwrite);
 }

"mkdir" interface is added to file operations.
This is a preparatory change as mkdir support for FAT file system will be added in next patch.

Signed-off-by AKASHI Takahiro <[email protected]>

---
 fs/fs.c      | 45 +++++++++++++++++++++++++++++++++++++++++++++
 include/fs.h | 10 ++++++++++
 2 files changed, 55 insertions(+)

fs/fs.c +6 -0

index 33808d549e..3cb6b21fe9 100644
@@ -105,6 +105,11 @@ static inline int fs_opendir_unsupported(const char *filename,
 	return -EACCES;
 }
 
+static inline int fs_mkdir_unsupported(const char *dirname)
+{
+	return -1;
+}
+
 struct fstype_info {
 	int fstype;
 	char *name;

@@ -142,6 +147,7 @@ struct fstype_info {
 	int (*readdir)(struct fs_dir_stream *dirs, struct fs_dirent **dentp);
 	/* see fs_closedir() */
 	void (*closedir)(struct fs_dir_stream *dirs);
+	int (*mkdir)(const char *dirname);
 };
 
 static struct fstype_info fstypes[] = {

fs/fs.c +5 -0

 	},
 #endif
 #ifdef CONFIG_FS_EXT4

@@ -185,6 +192,7 @@ static struct fstype_info fstypes[] = {
 #endif
 		.uuid = ext4fs_uuid,
 		.opendir = fs_opendir_unsupported,
+		.mkdir = fs_mkdir_unsupported,
 	},
 #endif
 #ifdef CONFIG_SANDBOX

@@ -201,6 +209,7 @@ static struct fstype_info fstypes[] = {
 		.write = fs_write_sandbox,
 		.uuid = fs_uuid_unsupported,
 		.opendir = fs_opendir_unsupported,
+		.mkdir = fs_mkdir_unsupported,
 	},
 #endif
 #ifdef CONFIG_CMD_UBIFS

@@ -217,6 +226,7 @@ static struct fstype_info fstypes[] = {
 		.write = fs_write_unsupported,
 		.uuid = fs_uuid_unsupported,
 		.opendir = fs_opendir_unsupported,
+		.mkdir = fs_mkdir_unsupported,
 	},
 #endif
 #ifdef CONFIG_FS_BTRFS

@@ -233,6 +243,7 @@ static struct fstype_info fstypes[] = {
 		.write = fs_write_unsupported,
 		.uuid = btrfs_uuid,
 		.opendir = fs_opendir_unsupported,
+		.mkdir = fs_mkdir_unsupported,
 	},
 #endif
 	{

@@ -248,6 +259,7 @@ static struct fstype_info fstypes[] = {
 		.write = fs_write_unsupported,
 		.uuid = fs_uuid_unsupported,
 		.opendir = fs_opendir_unsupported,
+		.mkdir = fs_mkdir_unsupported,
 	},
 };