[PATCH 1/4] fs: fat: propagate actual error code when opening/creating files

[PATCH 1/4] fs: fat: propagate actual error code when opening/creating files

[Ahmad Fatoum]

We currently map all error codes to -EINVAL when opening or creating a
file, when the underlying functions are capable of returning more error
codes like -EISDIR or -EROFS.

Propagate the received error code to tell consumers more about what went
wrong.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 fs/fat/fat.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index 0402db1d945a..b17157d1ea34 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -89,7 +89,7 @@ static int fat_create(struct device *dev, const char *pathname, mode_t mode)
 
 	ret = f_open(&priv->fat, &f_file, pathname, FA_OPEN_ALWAYS);
 	if (ret)
-		return -EINVAL;
+		return ret;
 
 	f_close(&f_file);
 
@@ -204,7 +204,7 @@ static int fat_open(struct device *dev, struct file *file, const char *filename)
 	ret = f_open(&priv->fat, f_file, filename, flags);
 	if (ret) {
 		free(f_file);
-		return -EINVAL;
+		return ret;
 	}
 
 	if (file->f_flags & O_APPEND) {
@@ -212,7 +212,7 @@ static int fat_open(struct device *dev, struct file *file, const char *filename)
 		if (ret) {
 			f_close(f_file);
 			free(f_file);
-			return -EINVAL;
+			return ret;
 		}
 	}
 
-- 
2.47.3

[PATCH 2/4] fs: fat: drop stray printf debug output

[Ahmad Fatoum]

There appears to be nothing special here that warrants printing this
message irrespective of log level.

As there are no other debug prints in the file, just drop it.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 fs/fat/ff.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/fs/fat/ff.c b/fs/fat/ff.c
index 89b4f9fa5de7..e4d83a35605f 100644
--- a/fs/fat/ff.c
+++ b/fs/fat/ff.c
@@ -1957,7 +1957,6 @@ int f_write (
 				fp->clust = clst;		/* Update current cluster */
 			}
 			if (fp->flag & FA__DIRTY) {		/* Write-back sector cache */
-				printf("wr sector cache\n");
 				if (disk_write(fp->fs, fp->buf, fp->dsect, 1) != RES_OK)
 					ABORT(fp->fs, -EIO);
 				fp->flag &= ~FA__DIRTY;
-- 
2.47.3

[PATCH 3/4] fs: fat: use fixed-width 32-bit FatFs types

[Ahmad Fatoum]

The comment already says LONG/ULONG/DWORD types should be 32-bit, but
barebox's long is always pointer-sized, so 64-bit on 64-bit platforms.

Use explicit 32-bit types for the FatFs fields that are written to disk
or used in sector calculations.

Assisted-by: Codex:gpt-5.5
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 fs/fat/fat.c     | 4 ++--
 fs/fat/ff.c      | 9 ++++++++-
 fs/fat/integer.h | 8 +++++---
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index b17157d1ea34..b50867524a74 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -52,7 +52,7 @@ DRESULT disk_read(FATFS *fat, BYTE *buf, DWORD sector, BYTE count)
 	size_t len = count * sector_size;
 	int ret;
 
-	debug("%s: sector: %ld count: %d\n", __func__, sector, count);
+	debug("%s: sector: %u count: %d\n", __func__, sector, count);
 
 	ret = cdev_read(priv->cdev, buf, len, (loff_t)sector * sector_size, 0);
 	if (ret != len)
@@ -68,7 +68,7 @@ DRESULT disk_write(FATFS *fat, const BYTE *buf, DWORD sector, BYTE count)
 	size_t len = count * sector_size;
 	int ret;
 
-	debug("%s: buf: %p sector: %ld count: %d\n",
+	debug("%s: buf: %p sector: %u count: %d\n",
 			__func__, buf, sector, count);
 
 	ret = cdev_write(priv->cdev, buf, len, (loff_t)sector * sector_size, 0);
diff --git a/fs/fat/ff.c b/fs/fat/ff.c
index e4d83a35605f..2f4e3b14f0a5 100644
--- a/fs/fat/ff.c
+++ b/fs/fat/ff.c
@@ -1539,14 +1539,21 @@ static enum filetype check_fs (	/* 0:The FAT BR, 1:Valid BR but not an FAT, 2:No
 	DWORD *bootsec
 )
 {
+	unsigned long bootsec_ul = 0;
 	DRESULT ret;
+	enum filetype type;
 
 	/* Load boot record */
 	ret = disk_read(fs, fs->win, sect, 1);
 	if (ret)
 		return filetype_unknown;
 
-	return is_fat_or_mbr(fs->win, bootsec);
+	type = is_fat_or_mbr(fs->win, &bootsec_ul);
+
+	if (bootsec)
+		*bootsec = bootsec_ul;
+
+	return type;
 }
 
 /*
diff --git a/fs/fat/integer.h b/fs/fat/integer.h
index fe94e374f356..d8b13402afe3 100644
--- a/fs/fat/integer.h
+++ b/fs/fat/integer.h
@@ -7,6 +7,8 @@
 #ifndef _INTEGER
 #define _INTEGER
 
+#include <linux/types.h>
+
 /* These types must be 16-bit, 32-bit or larger integer */
 typedef int		INT;
 typedef unsigned int	UINT;
@@ -23,8 +25,8 @@ typedef unsigned short	WORD;
 typedef unsigned short	WCHAR;
 
 /* These types must be 32-bit integer */
-typedef long		LONG;
-typedef unsigned long	ULONG;
-typedef unsigned long	DWORD;
+typedef s32		LONG;
+typedef u32		ULONG;
+typedef u32		DWORD;
 
 #endif
-- 
2.47.3

[PATCH 4/4] fs: fat: flush metadata updates to the block device

[Ahmad Fatoum]

The disk_ioctl glue that barebox provides can take a CTRL_SYNC command,
but barebox implemented it as a no-op.

Instead, various file system callbacks did flushing manually instead
of having fat.c do it via disk_ioctl.

Implement disk_ioctl(..., CTRL_SYNC) and drop the now superfluous
flushes.

Assisted-by: Codex:gpt-5.5
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 fs/fat/diskio.h     |  1 +
 fs/fat/fat-diskio.c |  4 ++++
 fs/fat/fat.c        | 46 ++++++++++++++-------------------------------
 3 files changed, 19 insertions(+), 32 deletions(-)

diff --git a/fs/fat/diskio.h b/fs/fat/diskio.h
index 04a587e3bc47..86fa0f21e365 100644
--- a/fs/fat/diskio.h
+++ b/fs/fat/diskio.h
@@ -40,6 +40,7 @@ DSTATUS disk_status (FATFS *fatfs);
 DRESULT disk_read (FATFS *fatfs, BYTE*, DWORD, BYTE);
 #if	_READONLY == 0
 DRESULT disk_write (FATFS *fatfs, const BYTE*, DWORD, BYTE);
+DRESULT disk_flush (FATFS *fatfs);
 #endif
 DRESULT disk_ioctl (FATFS *fatfs, BYTE, void*);
 
diff --git a/fs/fat/fat-diskio.c b/fs/fat/fat-diskio.c
index 6ba18993b870..8e26b6b1e9bb 100644
--- a/fs/fat/fat-diskio.c
+++ b/fs/fat/fat-diskio.c
@@ -28,7 +28,11 @@ DRESULT disk_ioctl (FATFS *fat, BYTE command, void *buf)
 		*(WORD *)buf = disk_sector_size(fat);
 		return RES_OK;
 	case CTRL_SYNC:
+#if	_READONLY == 0
+		return disk_flush(fat);
+#else
 		return RES_OK;
+#endif
 	default:
 		return RES_PARERR;
 	}
diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index b50867524a74..c2e6969f8109 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -78,6 +78,13 @@ DRESULT disk_write(FATFS *fat, const BYTE *buf, DWORD sector, BYTE count)
 	return RES_OK;
 }
 
+DRESULT disk_flush(FATFS *fat)
+{
+	struct fat_priv *priv = fat->userdata;
+
+	return cdev_flush(priv->cdev) ? RES_ERROR : RES_OK;
+}
+
 /* ---------------------------------------------------------------*/
 
 #ifdef CONFIG_FS_FAT_WRITE
@@ -91,51 +98,28 @@ static int fat_create(struct device *dev, const char *pathname, mode_t mode)
 	if (ret)
 		return ret;
 
-	f_close(&f_file);
-
-	return 0;
+	return f_close(&f_file);
 }
 
 static int fat_unlink(struct device *dev, const char *pathname)
 {
 	struct fat_priv *priv = dev->priv;
-	int ret;
 
-	ret = f_unlink(&priv->fat, pathname);
-	if (ret)
-		return ret;
-
-	cdev_flush(priv->cdev);
-
-	return 0;
+	return f_unlink(&priv->fat, pathname);
 }
 
 static int fat_mkdir(struct device *dev, const char *pathname)
 {
 	struct fat_priv *priv = dev->priv;
-	int ret;
 
-	ret = f_mkdir(&priv->fat, pathname);
-	if (ret)
-		return ret;
-
-	cdev_flush(priv->cdev);
-
-	return 0;
+	return f_mkdir(&priv->fat, pathname);
 }
 
 static int fat_rmdir(struct device *dev, const char *pathname)
 {
 	struct fat_priv *priv = dev->priv;
-	int ret;
 
-	ret = f_unlink(&priv->fat, pathname);
-	if (ret)
-		return ret;
-
-	cdev_flush(priv->cdev);
-
-	return 0;
+	return f_unlink(&priv->fat, pathname);
 }
 
 static int fat_write(struct file *f, const void *buf, size_t insize)
@@ -224,16 +208,14 @@ static int fat_open(struct device *dev, struct file *file, const char *filename)
 
 static int fat_close(struct device *dev, struct file *f)
 {
-	struct fat_priv *priv = dev->priv;
 	FIL *f_file = f->private_data;
+	int ret;
 
-	f_close(f_file);
+	ret = f_close(f_file);
 
 	free(f_file);
 
-	cdev_flush(priv->cdev);
-
-	return 0;
+	return ret;
 }
 
 static int fat_read(struct file *f, void *buf, size_t insize)
-- 
2.47.3

Re: [PATCH 1/4] fs: fat: propagate actual error code when opening/creating files

[Sascha Hauer]

On Tue, 25 Aug 2026 12:10:53 +0200, Ahmad Fatoum wrote:
> We currently map all error codes to -EINVAL when opening or creating a
> file, when the underlying functions are capable of returning more error
> codes like -EISDIR or -EROFS.
> 
> Propagate the received error code to tell consumers more about what went
> wrong.
> 
> [...]

Applied, thanks!

[1/4] fs: fat: propagate actual error code when opening/creating files
      https://git.pengutronix.de/cgit/barebox/commit/?id=228a800d9599 (link may not be stable)
[2/4] fs: fat: drop stray printf debug output
      https://git.pengutronix.de/cgit/barebox/commit/?id=99cee192dbee (link may not be stable)
[3/4] fs: fat: use fixed-width 32-bit FatFs types
      https://git.pengutronix.de/cgit/barebox/commit/?id=f2c889bed1b2 (link may not be stable)
[4/4] fs: fat: flush metadata updates to the block device
      https://git.pengutronix.de/cgit/barebox/commit/?id=6d149f6ff875 (link may not be stable)

Best regards,
-- 
Sascha Hauer <s.hauer@pengutronix.de>