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Subject[PATCH] cifs: Add information about noserverino
Date
In my case I had the problem that 32 bit userspace applications in an
amd64 environment was not able to list the directories of a CIFS-mounted
share. The simple userspace code

int main(int argc, char *argv[])
{
DIR *dir;
struct dirent *dirent;

if (!argv[1]) {
fprintf(stderr, "Usage: %s <directory>\n", argv[0]);
return -1;
}

dir = opendir(argv[1]);
if (!dir) {
perror("Unable to open directory");
return -1;
}

while ((dirent = readdir(dir)) != NULL)
puts(dirent->d_name);

closedir(dir);

return 0;
}

was sufficient to trigger the problem.

I discovered that the problem was that the inodes were too large to fit
in a 32 bit (unsigned long) integer, so the compat_filldir() function
returned -EOVERFLOW.

While that is okay it would have saved me a some hours of debugging if
the message below would have appeared in my kernel log.

The target was a Samba server (I guess) of a Buffalo LinkStation Duo
with the unmodified vendor firmware 1.34.

Signed-off-by: Bernhard Walle <bernhard@bwalle.de>
---
fs/cifs/readdir.c | 23 +++++++++++++++++++----
1 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index d5e591f..d979826 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -773,6 +773,7 @@ int cifs_readdir(struct file *file, void *direntry, filldir_t filldir)
char *tmp_buf = NULL;
char *end_of_smb;
unsigned int max_len;
+ int err;

xid = GetXid();

@@ -783,17 +784,31 @@ int cifs_readdir(struct file *file, void *direntry, filldir_t filldir)

switch ((int) file->f_pos) {
case 0:
- if (filldir(direntry, ".", 1, file->f_pos,
- file->f_path.dentry->d_inode->i_ino, DT_DIR) < 0) {
+ err = filldir(direntry, ".", 1, file->f_pos,
+ file->f_path.dentry->d_inode->i_ino, DT_DIR);
+ if (err < 0) {
cERROR(1, "Filldir for current dir failed");
+ if (err == -EOVERFLOW) {
+ cERROR(1, "Server inodes are too large for 32 "
+ "bit userspace. You might "
+ "consider using 'noserverino' "
+ "mount option for this mount.");
+ }
rc = -ENOMEM;
break;
}
file->f_pos++;
case 1:
- if (filldir(direntry, "..", 2, file->f_pos,
- file->f_path.dentry->d_parent->d_inode->i_ino, DT_DIR) < 0) {
+ err = filldir(direntry, "..", 2, file->f_pos,
+ file->f_path.dentry->d_parent->d_inode->i_ino, DT_DIR);
+ if (err < 0) {
cERROR(1, "Filldir for parent dir failed");
+ if (err == -EOVERFLOW) {
+ cERROR(1, "Server inodes are too large for 32 "
+ "bit userspace. You might "
+ "consider using 'noserverino' "
+ "mount option for this mount.");
+ }
rc = -ENOMEM;
break;
}
--
1.7.3.2


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