src, branch zfs-0.6.2

Tag zfs-0.6.2

2013-08-22T20:33:26Z

META file and release log updated. Signed-off-by: Brian Behlendorf

Use directory xattrs for symlinks

2013-08-22T20:30:44Z

There is currently a subtle bug in the SA implementation which can crop up which prevents us from safely using multiple variable length SAs in one object. Fortunately, the only existing use case for this are symlinks with SA based xattrs. Therefore, until the root cause in the SA code can be identified and fixed we prevent adding SA xattrs to symlinks. Signed-off-by: Brian Behlendorf Issue #1468

Revert "Evict meta data from ghost lists + l2arc headers"

2013-08-22T19:15:37Z

This reverts commit fadd0c4da1e2ccd6014800d8b1a0fd117dd323e8 which introduced a regression in honoring the meta limit. Signed-off-by: Brian Behlendorf Close #1660

Implement database to workaround misreported physical sector sizes

2013-08-22T18:24:06Z

This implements vdev_bdev_database_check(). It alters the detected sector size of any device listed in a database of drives known to lie about their physical sector sizes. This is based on "6931570 Add flash devices' VID/PID to disk table to advertising 4K physical sector size" from Open Solaris and on sg_simple4.c from sg3_utils. About two dozen lines are taken from sg_simple4.c, which is GPLv2 licensed. However, sg_simple4.c is analogous to a Hello World program and is safe for us to use. We requested that Douglas Gilbert, the author of sg_simple4.c, confirm that this is the case. A cutdown version of his response is as follows: ``` I would consider a SCSI INQUIRY example using the Linux sg driver interface (also written by me) as the equivalent of an "hello world" program in C. ``` The database was created with the help of the freenode and ZFSOnLinux communities. Some notes: 1. The following drives both were confirmed to lie via reports in IRC and they contain capacity information in their identifiers: INTEL SSDSA2M080 INTEL SSDSA2M160 M4-CT256M4SSD2 WDC WD15EARS-00S WDC WD15EARS-00Z WDC WD20EARS-00M The identifiers for different capacity models were extrapolated and added under the assumption that those models also lie. Google was used to verify that the extrapolated drive identifiers existed prior to their inclusion. 2. The OCZ-VERTEX2 3.5 identifer applies to two drives that differ solely in page size (and slightly in capacity). One uses 4096-byte pages and the other uses 8192-byte pages. Both are set to use 8192-byte pages. We could detect the page size by checking the capacity, but that would unnecessarily complicate the code. 3. It is possible for updated drive firmware to correctly report the sector size. There were reports of a few advanced format drives doing that. One report stated that the vendor changed the identification string while another was unclear on this. Both reports involved WDC models. 4. Google was used to determine the size of pages in the listed flash devices. Reports of 8192-byte pages took precedence over reports of 4096-byte pages. 5. Devices behind USB adapters can have their identification strings altered. Identification strings obtained across USB adapters are omitted and no attempt is made to correct for alterations made by USB adapters when doing comparisons against the database. Two entries in the Open Solaris database that appear to have been altered by a USB adapter were omitted. Signed-off-by: Richard Yao Signed-off-by: Brian Behlendorf Closes #1652

Linux 3.11 compat: fops->iterate()

2013-08-15T23:19:07Z

Commit torvalds/linux@2233f31aade393641f0eaed43a71110e629bb900 replaced ->readdir() with ->iterate() in struct file_operations. All filesystems must now use the new ->iterate method. To handle this the code was reworked to use the new ->iterate interface. Care was taken to keep the majority of changes confined to the ZPL layer which is already Linux specific. However, minor changes were required to the common zfs_readdir() function. Compatibility with older kernels was accomplished by adding versions of the trivial dir_emit* helper functions. Also the various *_readdir() functions were reworked in to wrappers which create a dir_context structure to pass to the new *_iterate() functions. Unfortunately, the new dir_emit* functions prevent us from passing a private pointer to the filldir function. The xattr directory code leveraged this ability through zfs_readdir() to generate the list of xattr names. Since we can no longer use zfs_readdir() a simplified zpl_xattr_readdir() function was added to perform the same task. Signed-off-by: Richard Yao Signed-off-by: Brian Behlendorf Closes #1653 Issue #1591

Fix z_wr_iss_h zio_execute() import hang

2013-08-15T22:20:36Z

Because we need to be more frugal about our stack usage under Linux. The __zio_execute() function was modified to re-dispatch zios to a ZIO_TASKQ_ISSUE thread when we're in a context which is known to be stack heavy. Those two contexts are the sync thread and what ever thread is performing spa initialization. Unfortunately, this change introduced an unlikely bug which can result in a zio being re-dispatched indefinitely and never being executed. If during spa initialization we handle a zio with ZIO_PRIORITY_NOW it will be moved to the high priority queue. When __zio_execute() is called again for the zio it will mis- interpret the context and re-dispatch it again. The system will get stuck spinning re-dispatching the zio and making no forward progress. To fix this rare issue __zio_execute() has been updated not to re-dispatch zios on either the ZIO_TASKQ_ISSUE or ZIO_TASKQ_ISSUE_HIGH task queues. In practice this issue was rarely reported and can usually be fixed by rebooting the system and importing the pool again. Signed-off-by: Brian Behlendorf Closes #1455

Don't specifically open /etc/mtab - it is done in libzfs_init()

2013-08-15T17:19:38Z

a few lines further down and we can share the open file handle. Signed-off-by: Brian Behlendorf Issue #1498

No point in rewind() mtab in zfs_unshare_proto(). We're not really

2013-08-15T17:18:31Z

reading the file, but instead use libzfs_mnttab_find() which does the nessesary freopen() for us. Signed-off-by: Brian Behlendorf Issue #1498

Use setmntent() OR fopen()

2013-08-15T17:09:09Z

For the same reasons it's used in libzfs_init(), this was just overlooked because zinject gets minimal use. Signed-off-by: Brian Behlendorf Issue #1498

Fix for re-reading /etc/mtab in zfs_is_mounted()

2013-08-14T18:37:06Z

When /etc/mtab is updated on Linux it's done atomically with rename(2). A new mtab is written, the existing mtab is unlinked, and the new mtab is renamed to /etc/mtab. This means that we must close the old file and open the new file to get the updated contents. Using rewind(3) will just move the file pointer back to the start of the file, freopen(3) will close and open the file. Signed-off-by: Brian Behlendorf Closes #1611