[PATCH v2 0/5] exfat: Fixes for ENAMETOOLONG error handling

[PATCH v2 0/5] exfat: Fixes for ENAMETOOLONG error handling

[Takashi Iwai]

Hi,

this is a revised series for fixing the error code of rename syscall
as well as cleanup / suppress the superfluous error messages.

As an LTP test case reported, exfat returns the inconsistent error
code for the case of renaming oversized file names:
  https://bugzilla.suse.com/show_bug.cgi?id=1201725
The first patch fixes this inconsistency.

The second patch is just for correcting the definitions as bit flags,
and the remaining two patches are for suppressing the error message
that can be triggered too easily to debug messages.


thanks,

Takashi

===

v1: https://lore.kernel.org/r/20220722142916.29435-1-tiwai@suse.de

v1->v2:
* Expand to pr_*() directly in exfat_*() macros
* Add a patch to drop superfluous newlines in error messages

===

Takashi Iwai (5):
  exfat: Return ENAMETOOLONG consistently for oversized paths
  exfat: Define NLS_NAME_* as bit flags explicitly
  exfat: Expand exfat_err() and co directly to pr_*() macro
  exfat: Downgrade ENAMETOOLONG error message to debug messages
  exfat: Drop superfluous new line for error messages

 fs/exfat/exfat_fs.h | 18 ++++++++++--------
 fs/exfat/fatent.c   |  2 +-
 fs/exfat/misc.c     | 17 -----------------
 fs/exfat/namei.c    |  2 +-
 fs/exfat/nls.c      |  4 ++--
 fs/exfat/super.c    |  4 ++--
 6 files changed, 16 insertions(+), 31 deletions(-)

-- 
2.35.3

[PATCH v2 1/5] exfat: Return ENAMETOOLONG consistently for oversized paths

[Takashi Iwai]

LTP has a test for oversized file path renames and it expects the
return value to be ENAMETOOLONG.  However, exfat returns EINVAL
unexpectedly in some cases, hence LTP test fails.  The further
investigation indicated that the problem happens only when iocharset
isn't set to utf8.

The difference comes from that, in the case of utf8,
exfat_utf8_to_utf16() returns the error -ENAMETOOLONG directly and
it's treated as the final error code.  Meanwhile, on other iocharsets,
exfat_nls_to_ucs2() returns the max path size but it sets
NLS_NAME_OVERLEN to lossy flag instead; the caller side checks only
whether lossy flag is set or not, resulting in always -EINVAL
unconditionally.

This patch aligns the return code for both cases by checking the lossy
flag bit and returning ENAMETOOLONG when NLS_NAME_OVERLEN bit is set.

BugLink: https://bugzilla.suse.com/show_bug.cgi?id=1201725
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 fs/exfat/namei.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index c6eaf7e9ea74..bcb6445eb3b3 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -462,7 +462,7 @@ static int __exfat_resolve_path(struct inode *inode, const unsigned char *path,
 		return namelen; /* return error value */
 
 	if ((lossy && !lookup) || !namelen)
-		return -EINVAL;
+		return (lossy & NLS_NAME_OVERLEN) ? -ENAMETOOLONG : -EINVAL;
 
 	exfat_chain_set(p_dir, ei->start_clu,
 		EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);
-- 
2.35.3

[PATCH v2 2/5] exfat: Define NLS_NAME_* as bit flags explicitly

[Takashi Iwai]

NLS_NAME_* are bit flags although they are currently defined as enum;
it's casually working so far (from 0 to 2), but it's error-prone and
may bring a problem when we want to add more flag.

This patch changes the definitions of NLS_NAME_* explicitly being bit
flags.

Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 fs/exfat/exfat_fs.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index 4a7a2308eb72..f431327af459 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/exfat_fs.h
@@ -27,9 +27,9 @@ enum exfat_error_mode {
  * exfat nls lossy flag
  */
 enum {
-	NLS_NAME_NO_LOSSY,	/* no lossy */
-	NLS_NAME_LOSSY,		/* just detected incorrect filename(s) */
-	NLS_NAME_OVERLEN,	/* the length is over than its limit */
+	NLS_NAME_NO_LOSSY =	0,	/* no lossy */
+	NLS_NAME_LOSSY =	1 << 0,	/* just detected incorrect filename(s) */
+	NLS_NAME_OVERLEN =	1 << 1,	/* the length is over than its limit */
 };
 
 #define EXFAT_HASH_BITS		8
-- 
2.35.3

[PATCH v2 3/5] exfat: Expand exfat_err() and co directly to pr_*() macro

[Takashi Iwai]

Currently the error and info messages handled by exfat_err() and co
are tossed to exfat_msg() function that does nothing but passes the
strings with printk() invocation.  Not only that this is more overhead
by the indirect calls, but also this makes harder to extend for the
debug print usage; because of the direct printk() call, you cannot
make it for dynamic debug or without debug like the standard helpers
such as pr_debug() or dev_dbg().

For addressing the problem, this patch replaces exfat_*() macro to
expand to pr_*() directly.  Along with it, add the new exfat_debug()
macro that is expanded to pr_debug() (which output can be gracefully
suppressed via dyndbg).

Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 fs/exfat/exfat_fs.h | 12 +++++++-----
 fs/exfat/misc.c     | 17 -----------------
 2 files changed, 7 insertions(+), 22 deletions(-)

diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index f431327af459..f9f0671515aa 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/exfat_fs.h
@@ -508,14 +508,16 @@ void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
 #define exfat_fs_error_ratelimit(sb, fmt, args...) \
 		__exfat_fs_error(sb, __ratelimit(&EXFAT_SB(sb)->ratelimit), \
 		fmt, ## args)
-void exfat_msg(struct super_block *sb, const char *lv, const char *fmt, ...)
-		__printf(3, 4) __cold;
+
+/* expand to pr_*() with prefix */
 #define exfat_err(sb, fmt, ...)						\
-	exfat_msg(sb, KERN_ERR, fmt, ##__VA_ARGS__)
+	pr_err("exFAT-fs (%s): " fmt "\n", (sb)->s_id, ##__VA_ARGS__)
 #define exfat_warn(sb, fmt, ...)					\
-	exfat_msg(sb, KERN_WARNING, fmt, ##__VA_ARGS__)
+	pr_warn("exFAT-fs (%s): " fmt "\n", (sb)->s_id, ##__VA_ARGS__)
 #define exfat_info(sb, fmt, ...)					\
-	exfat_msg(sb, KERN_INFO, fmt, ##__VA_ARGS__)
+	pr_info("exFAT-fs (%s): " fmt "\n", (sb)->s_id, ##__VA_ARGS__)
+#define exfat_debug(sb, fmt, ...)					\
+	pr_debug("exFAT-fs (%s): " fmt "\n", (sb)->s_id, ##__VA_ARGS__)
 
 void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
 		u8 tz, __le16 time, __le16 date, u8 time_cs);
diff --git a/fs/exfat/misc.c b/fs/exfat/misc.c
index 9380e0188b55..2e1a1a6b1021 100644
--- a/fs/exfat/misc.c
+++ b/fs/exfat/misc.c
@@ -46,23 +46,6 @@ void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
 	}
 }
 
-/*
- * exfat_msg() - print preformated EXFAT specific messages.
- * All logs except what uses exfat_fs_error() should be written by exfat_msg()
- */
-void exfat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
-{
-	struct va_format vaf;
-	va_list args;
-
-	va_start(args, fmt);
-	vaf.fmt = fmt;
-	vaf.va = &args;
-	/* level means KERN_ pacility level */
-	printk("%sexFAT-fs (%s): %pV\n", level, sb->s_id, &vaf);
-	va_end(args);
-}
-
 #define SECS_PER_MIN    (60)
 #define TIMEZONE_SEC(x)	((x) * 15 * SECS_PER_MIN)
 
-- 
2.35.3

[PATCH v2 4/5] exfat: Downgrade ENAMETOOLONG error message to debug messages

[Takashi Iwai]

The ENAMETOOLONG error message is printed at each time when user tries
to operate with a too long name, and this can flood the kernel logs
easily, as every user can trigger this.  Let's downgrade this error
message level to a debug message for suppressing the superfluous
logs.

BugLink: https://bugzilla.suse.com/show_bug.cgi?id=1201725
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 fs/exfat/nls.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/exfat/nls.c b/fs/exfat/nls.c
index ef115e673406..617aa1272265 100644
--- a/fs/exfat/nls.c
+++ b/fs/exfat/nls.c
@@ -509,7 +509,7 @@ static int exfat_utf8_to_utf16(struct super_block *sb,
 	}
 
 	if (unilen > MAX_NAME_LENGTH) {
-		exfat_err(sb, "failed to %s (estr:ENAMETOOLONG) nls len : %d, unilen : %d > %d",
+		exfat_debug(sb, "failed to %s (estr:ENAMETOOLONG) nls len : %d, unilen : %d > %d",
 			  __func__, len, unilen, MAX_NAME_LENGTH);
 		return -ENAMETOOLONG;
 	}
-- 
2.35.3

[PATCH v2 5/5] exfat: Drop superfluous new line for error messages

[Takashi Iwai]

exfat_err() adds the new line at the end of the message by itself,
hence the passed string shouldn't contain a new line.  Drop the
superfluous newline letters in the error messages in a few places that
have been put mistakenly.

Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 fs/exfat/fatent.c | 2 +-
 fs/exfat/nls.c    | 2 +-
 fs/exfat/super.c  | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/exfat/fatent.c b/fs/exfat/fatent.c
index 9de6a6b844c9..ee0b7cf51157 100644
--- a/fs/exfat/fatent.c
+++ b/fs/exfat/fatent.c
@@ -331,7 +331,7 @@ int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
 	/* find new cluster */
 	if (hint_clu == EXFAT_EOF_CLUSTER) {
 		if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) {
-			exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)\n",
+			exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)",
 				  sbi->clu_srch_ptr);
 			sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
 		}
diff --git a/fs/exfat/nls.c b/fs/exfat/nls.c
index 617aa1272265..705710f93e2d 100644
--- a/fs/exfat/nls.c
+++ b/fs/exfat/nls.c
@@ -671,7 +671,7 @@ static int exfat_load_upcase_table(struct super_block *sb,
 
 		bh = sb_bread(sb, sector);
 		if (!bh) {
-			exfat_err(sb, "failed to read sector(0x%llx)\n",
+			exfat_err(sb, "failed to read sector(0x%llx)",
 				  (unsigned long long)sector);
 			ret = -EIO;
 			goto free_table;
diff --git a/fs/exfat/super.c b/fs/exfat/super.c
index 6a4dfe9f31ee..35f0305cd493 100644
--- a/fs/exfat/super.c
+++ b/fs/exfat/super.c
@@ -464,7 +464,7 @@ static int exfat_read_boot_sector(struct super_block *sb)
 	 */
 	if (p_boot->sect_size_bits < EXFAT_MIN_SECT_SIZE_BITS ||
 	    p_boot->sect_size_bits > EXFAT_MAX_SECT_SIZE_BITS) {
-		exfat_err(sb, "bogus sector size bits : %u\n",
+		exfat_err(sb, "bogus sector size bits : %u",
 				p_boot->sect_size_bits);
 		return -EINVAL;
 	}
@@ -473,7 +473,7 @@ static int exfat_read_boot_sector(struct super_block *sb)
 	 * sect_per_clus_bits could be at least 0 and at most 25 - sect_size_bits.
 	 */
 	if (p_boot->sect_per_clus_bits > EXFAT_MAX_SECT_PER_CLUS_BITS(p_boot)) {
-		exfat_err(sb, "bogus sectors bits per cluster : %u\n",
+		exfat_err(sb, "bogus sectors bits per cluster : %u",
 				p_boot->sect_per_clus_bits);
 		return -EINVAL;
 	}
-- 
2.35.3

Re: [PATCH v2 0/5] exfat: Fixes for ENAMETOOLONG error handling

[Namjae Jeon]

2022-07-26 17:39 GMT+09:00, Takashi Iwai <tiwai@suse.de>:
> Hi,
>
> this is a revised series for fixing the error code of rename syscall
> as well as cleanup / suppress the superfluous error messages.
>
> As an LTP test case reported, exfat returns the inconsistent error
> code for the case of renaming oversized file names:
>   https://bugzilla.suse.com/show_bug.cgi?id=1201725
> The first patch fixes this inconsistency.
>
> The second patch is just for correcting the definitions as bit flags,
> and the remaining two patches are for suppressing the error message
> that can be triggered too easily to debug messages.
Applied, Thanks for your work!
>
>
> thanks,
>
> Takashi
>
> ===
>
> v1: https://lore.kernel.org/r/20220722142916.29435-1-tiwai@suse.de
>
> v1->v2:
> * Expand to pr_*() directly in exfat_*() macros
> * Add a patch to drop superfluous newlines in error messages
>
> ===
>
> Takashi Iwai (5):
>   exfat: Return ENAMETOOLONG consistently for oversized paths
>   exfat: Define NLS_NAME_* as bit flags explicitly
>   exfat: Expand exfat_err() and co directly to pr_*() macro
>   exfat: Downgrade ENAMETOOLONG error message to debug messages
>   exfat: Drop superfluous new line for error messages
>
>  fs/exfat/exfat_fs.h | 18 ++++++++++--------
>  fs/exfat/fatent.c   |  2 +-
>  fs/exfat/misc.c     | 17 -----------------
>  fs/exfat/namei.c    |  2 +-
>  fs/exfat/nls.c      |  4 ++--
>  fs/exfat/super.c    |  4 ++--
>  6 files changed, 16 insertions(+), 31 deletions(-)
>
> --
> 2.35.3
>
>