ID: 40893
Updated by: [EMAIL PROTECTED]
Reported By: andrew at digicol dot de
-Status: Open
+Status: Feedback
Bug Type: Filesystem function related
Operating System: Redhat EL4
PHP Version: 4.4.5
New Comment:
I'm unable to reproduce it and unable to track it down.
An account on this RH machine would help.
Previous Comments:
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[2007-03-24 13:19:37] andrew at digicol dot de
I have no solution, but an explanation:
Looking at the code for PHP's filestat.c we see:
When statfs is called, size is bytestotal = f_blocks * f_bsize
When statvfs is called, size is bytestotal = f_blocks * f_frsize
Looking at the system trace, which shows statfs, indicates f_bsize is
used, looking at what PHP actually shows for disk_total_space indicates
f_frsize is used in the calculation.
The problem with RedHat Linux seems to be that is has statvfs, but this
calls statfs internally. This is a problem, it confuses PHP about what
block size parameter to use for space calculations.
I add the following lines to the function disk_total_space in
ext/standard/filestat.c and re-compiled php:
#if defined(HAVE_SYS_STATVFS_H) && defined(HAVE_STATVFS)
syslog(LOG_INFO, "# include <sys/statvfs.h>\n");
#elif defined(HAVE_SYS_STATFS_H) && defined(HAVE_STATFS)
syslog(LOG_INFO, "# include <sys/statfs.h>\n");
#elif defined(HAVE_SYS_MOUNT_H) && defined(HAVE_STATFS)
syslog(LOG_INFO, "# include <sys/mount.h>\n");
#endif
The following command:
strace /dot/dc/bin/php-5.2.0-logging/bin/php -r 'echo
number_format(disk_total_space("/mnt")) . "\n";'
will show:
..
statfs("/mnt", {f_type="NFS_SUPER_MAGIC", f_bsize=32768,
f_blocks=9158253, f_bfree=5093336, f_bavail=5093336, f_files=0,
f_ffree=0, f_fsid={0, 0}, f_namelen=255, f_frsize=4096}) = 0
..
and the this appears in /var/log/messages:
Mar 24 14:02:20 dc5ora10gr2 php: # include <sys/statvfs.h>
I haven't looked at the source code for df but somehow it is able to
cope with it.
------------------------------------------------------------------------
[2007-03-22 21:26:56] andrew at digicol dot de
We get the correct sizes with df (I would not have considered posting
the bug report otherwise). We are using df (coreutils) 5.2.1 on RedHat.
The RedHat version is RHEL 4 btw, not 3.
Maybe it is an NFS-related bug that is handled gracefully in df.
------------------------------------------------------------------------
[2007-03-22 17:19:58] [EMAIL PROTECTED]
>From what I can see in df sources, it uses exactly the same logics as
PHP, so I don't really see how it's possible that you get correct values
with df, especially taking into account that the f_frsize is broken in
the same way there.
You might want to look at this RH bug:
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=146427
It says that RHEL3 U4 fixes it.
------------------------------------------------------------------------
[2007-03-22 15:38:21] andrew at digicol dot de
RedHat Linux:
strace /dot/dc/bin/php/bin/php -r 'echo
number_format(disk_total_space("/mnt")) . "\n";'
...
statfs("/mnt", {f_type="NFS_SUPER_MAGIC", f_bsize=32768,
f_blocks=9158253, f_bfree=5093458, f_bavail=5093458, f_files=0,
f_ffree=0, f_fsid={0, 0}, f_namelen=255, f_frsize=4096}) = 0
...
SuSE Linux:
strace php -r 'echo number_format(disk_total_space("/mnt")) . "\n";'
...
statfs("/mnt", {f_type="NFS_SUPER_MAGIC", f_bsize=32768,
f_blocks=9158253, f_bfree=5093458, f_bavail=5093458, f_files=0,
f_ffree=0, f_fsid={0, 0}, f_namelen=255, f_frsize=32768}) = 0
...
Just in case this helps, "df -h" seems to invoke the a different system
call (statfs64, both systems are 32-bit, I am not an expert regarding
system calls). They result in the same f_bsize and fr_size values.
Unlike php, df draws the correct conclusions regarding total / free
space on both systems:
RedHat Linux:
strace df -h
...
statfs64("/mnt", 84, {f_type="NFS_SUPER_MAGIC", f_bsize=32768,
f_blocks=9158253, f_bfree=5093460, f_bavail=5093460, f_files=0,
f_ffree=0, f_fsid={0, 0}, f_namelen=255, f_frsize=4096}) = 0
...
SuSE Linux:
strace df -h
...
statfs64("/mnt", 84, {f_type="NFS_SUPER_MAGIC", f_bsize=32768,
f_blocks=9158253, f_bfree=5093460, f_bavail=5093460, f_files=0,
f_ffree=0, f_fsid={0, 0}, f_namelen=255, f_frsize=32768}) = 0
...
------------------------------------------------------------------------
[2007-03-22 15:21:36] [EMAIL PROTECTED]
If you're still able to reproduce it - try to trace it and figure out
which blocksize is reported by the system and which function is used -
statvfs() or statfs().
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