XFS: Prepare for combining the XFS and Linux inodes.
cover XFS: Prepare for combining the XFS and Linux inodes.
These three patches clean up code in preparation for combining the Linux and XFS inodes. Each patch stands alone, but I've sent them as a series becausee they have all been written to make it easier to transition the code to an embedded struct inode in the struct xfs_inode.
PATCH 1/3 XFS: factor xfs_iget_core() into hit and miss cases
There are really two cases in xfs_iget_core(). The first is the cache hit case, the second is the miss case. They share very little code, and hence can easily be factored out into separate functions. This makes the code much easier to understand and subsequently modify.
--- fs/xfs/xfs_iget.c | 347 +++++++++++++++++++++++++++++------------------------ 1 files changed, 191 insertions(+), 156 deletions(-)
fs/xfs/xfs_iget.c +191 -156
@@ -40,161 +40,119 @@#include "xfs_utils.h" /* -* Look up an inode by number in the given file system. -* The inode is looked up in the cache held in each AG. -* If the inode is found in the cache, attach it to the provided -* vnode. -* -* If it is not in core, read it in from the file system's device, -* add it to the cache and attach the provided vnode. -* -* The inode is locked according to the value of the lock_flags parameter. -* This flag parameter indicates how and if the inode's IO lock and inode lock -* should be taken. -* -* mp -- the mount point structure for the current file system. It points -* to the inode hash table. -* tp -- a pointer to the current transaction if there is one. This is -* simply passed through to the xfs_iread() call. -* ino -- the number of the inode desired. This is the unique identifier -* within the file system for the inode being requested. -* lock_flags -- flags indicating how to lock the inode. See the comment -* for xfs_ilock() for a list of valid values. -* bno -- the block number starting the buffer containing the inode, -* if known (as by bulkstat), else 0. +* Check the validity of the inode we just found it the cache */ -STATIC int -xfs_iget_core ( -struct inode *inode, -xfs_mount_t *mp, -xfs_trans_t *tp, -xfs_ino_t ino, -uint flags, -uint lock_flags, -xfs_inode_t **ipp, -xfs_daddr_t bno) +static int +xfs_iget_cache_hit ( +struct inode *inode, +struct xfs_perag *pag, +struct xfs_inode *ip, +int flags, + int lock_flags) __releases(pag->pag_ici_lock) { -struct inode *old_inode; -xfs_inode_t *ip; -int error; -unsigned long first_index, mask; -xfs_perag_t *pag; -xfs_agino_t agino; - -/* the radix tree exists only in inode capable AGs */ -if (XFS_INO_TO_AGNO (mp, ino) >= mp->m_maxagi) -return EINVAL ; - -/* get the perag structure and ensure that it's inode capable */ - pag =xfs_get_perag (mp, ino); -if (!pag->pagi_inodeok) -return EINVAL ; -ASSERT (pag->pag_ici_init); - agino =XFS_INO_TO_AGINO (mp, ino); +struct xfs_mount *mp = ip->i_mount; +struct inode *old_inode; +int error =0 ; -again: -read_lock (&pag->pag_ici_lock); - ip =radix_tree_lookup (&pag->pag_ici_root, agino); +/* +* If INEW is set this inode is being set up +* Pause and try again. +*/ +if (xfs_iflags_test (ip,XFS_INEW )) { + error =EAGAIN ; +XFS_STATS_INC (xs_ig_frecycle); + goto out_error; + } -if (ip !=NULL ) { + old_inode = ip->i_vnode; +if (old_inode ==NULL ) {/* -* If INEW is set this inode is being set up +* If IRECLAIM is set this inode is +* on its way out of the system, * we need to pause and try again. */ -if (xfs_iflags_test (ip,XFS_INEW )) { -read_unlock (&pag->pag_ici_lock); -delay (1 ); +if (xfs_iflags_test (ip,XFS_IRECLAIM )) { + error =EAGAIN ;XFS_STATS_INC (xs_ig_frecycle); + goto out_error; + } +ASSERT (xfs_iflags_test (ip,XFS_IRECLAIMABLE )); - goto again; +/* +* If lookup is racing with unlink, then we +* should return an error immediately so we +* don't remove it from the reclaim list and +* potentially leak the inode. +*/ +if ((ip->i_d.di_mode ==0 ) && + !(flags &XFS_IGET_CREATE )) { + error =ENOENT ; + goto out_error; } +xfs_itrace_exit_tag (ip,"xfs_iget.alloc" ); + +xfs_iflags_clear (ip,XFS_IRECLAIMABLE ); +read_unlock (&pag->pag_ici_lock); + +XFS_MOUNT_ILOCK (mp); +list_del_init (&ip->i_reclaim); +XFS_MOUNT_IUNLOCK (mp); - old_inode = ip->i_vnode; -if (old_inode ==NULL ) { -/* -* If IRECLAIM is set this inode is -* on its way out of the system, -* we need to pause and try again. -*/ -if (xfs_iflags_test (ip,XFS_IRECLAIM )) { -read_unlock (&pag->pag_ici_lock); -delay (1 ); -XFS_STATS_INC (xs_ig_frecycle); - - goto again; - } -ASSERT (xfs_iflags_test (ip,XFS_IRECLAIMABLE )); - -/* -* If lookup is racing with unlink, then we -* should return an error immediately so we -* don't remove it from the reclaim list and -* potentially leak the inode. -*/ -if ((ip->i_d.di_mode ==0 ) && - !(flags &XFS_IGET_CREATE )) { -read_unlock (&pag->pag_ici_lock); -xfs_put_perag (mp, pag); -return ENOENT ; - } - -xfs_itrace_exit_tag (ip,"xfs_iget.alloc" ); - -XFS_STATS_INC (xs_ig_found); -xfs_iflags_clear (ip,XFS_IRECLAIMABLE ); -read_unlock (&pag->pag_ici_lock); - -XFS_MOUNT_ILOCK (mp); -list_del_init (&ip->i_reclaim); -XFS_MOUNT_IUNLOCK (mp); - - goto finish_inode; - - }else if (inode != old_inode) { -/* The inode is being torn down, pause and -* try again. -*/ -if (old_inode->i_state & (I_FREEING |I_CLEAR )) { -read_unlock (&pag->pag_ici_lock); -delay (1 ); -XFS_STATS_INC (xs_ig_frecycle); - - goto again; - } + }else if (inode != old_inode) { +/* The inode is being torn down, pause and +* try again. +*/ +if (old_inode->i_state & (I_FREEING |I_CLEAR )) { + error =EAGAIN ; +XFS_STATS_INC (xs_ig_frecycle); + goto out_error; + }/* Chances are the other vnode (the one in the inode) is being torn * down right now, and we landed on top of it. Question is, what do * we do? Unhook the old inode and hook up the new one? */ -cmn_err (CE_PANIC , -"xfs_iget_core: ambiguous vns: vp/0x%p, invp/0x%p" , - old_inode, inode); - } - -/* -* Inode cache hit -*/ +cmn_err (CE_PANIC , +"xfs_iget_core: ambiguous vns: vp/0x%p, invp/0x%p" , + old_inode, inode); + }else {read_unlock (&pag->pag_ici_lock); -XFS_STATS_INC (xs_ig_found); + } -finish_inode: -if (ip->i_d.di_mode ==0 && !(flags &XFS_IGET_CREATE )) { -xfs_put_perag (mp, pag); -return ENOENT ; - } +if (ip->i_d.di_mode ==0 && !(flags &XFS_IGET_CREATE )) { + error =ENOENT ; + goto out; + } -if (lock_flags !=0 ) -xfs_ilock (ip, lock_flags); +if (lock_flags !=0 ) +xfs_ilock (ip, lock_flags); -xfs_iflags_clear (ip,XFS_ISTALE ); -xfs_itrace_exit_tag (ip,"xfs_iget.found" ); - goto return_ip; - } +xfs_iflags_clear (ip,XFS_ISTALE ); +xfs_itrace_exit_tag (ip,"xfs_iget.found" ); +XFS_STATS_INC (xs_ig_found); +return 0 ; -/* -* Inode cache miss -*/ +out_error:read_unlock (&pag->pag_ici_lock); -XFS_STATS_INC (xs_ig_missed); +out: +return error; +} + + +static int +xfs_iget_cache_miss ( +struct xfs_mount *mp, +struct xfs_perag *pag, +xfs_trans_t *tp, +xfs_ino_t ino, +struct xfs_inode **ipp, +xfs_daddr_t bno, +int flags, +int lock_flags) +{ +struct xfs_inode *ip; +int error; +unsigned long first_index, mask; +xfs_agino_t agino =XFS_INO_TO_AGINO (mp, ino);/* * Read the disk inode attributes into a new inode structure and get
@@ -202,14 +160,11 @@ finish_inode:*/ error =xfs_iread (mp, tp, ino, &ip, bno, (flags &XFS_IGET_BULKSTAT ) ?XFS_IMAP_BULKSTAT :0 ); -if (error) { -xfs_put_perag (mp, pag); +if (error)return error; - }xfs_itrace_exit_tag (ip,"xfs_iget.alloc" ); -mrlock_init (&ip->i_lock,MRLOCK_ALLOW_EQUAL_PRI |MRLOCK_BARRIER ,"xfsino" , ip->i_ino);mrlock_init (&ip->i_iolock,MRLOCK_BARRIER ,"xfsio" , ip->i_ino);
@@ -228,9 +183,8 @@ finish_inode:xfs_ilock (ip, lock_flags);if ((ip->i_d.di_mode ==0 ) && !(flags &XFS_IGET_CREATE )) { -xfs_idestroy (ip); -xfs_put_perag (mp, pag); -return ENOENT ; + error =ENOENT ; + goto out_destroy; }/*
@@ -238,37 +192,110 @@ finish_inode:* write spinlock. */ if (radix_tree_preload (GFP_KERNEL )) { -xfs_idestroy (ip); -delay (1 ); - goto again; + error =EAGAIN ; + goto out_destroy; } mask = ~(((XFS_INODE_CLUSTER_SIZE (mp) >> mp->m_sb.sb_inodelog)) -1 ); first_index = agino & mask;write_lock (&pag->pag_ici_lock); -/* -* insert the new inode -*/ + +/* insert the new inode */ error =radix_tree_insert (&pag->pag_ici_root, agino, ip);if (unlikely (error)) { -BUG_ON (error != -EEXIST ); -write_unlock (&pag->pag_ici_lock); -radix_tree_preload_end (); -xfs_idestroy (ip); +WARN_ON (error != -EEXIST );XFS_STATS_INC (xs_ig_dup); - goto again; + error =EAGAIN ; + goto out_unlock; } -/* -* These values _must_ be set before releasing the radix tree lock! -*/ +/* These values _must_ be set before releasing the radix tree lock! */ ip->i_udquot = ip->i_gdquot =NULL ;xfs_iflags_set (ip,XFS_INEW );write_unlock (&pag->pag_ici_lock);radix_tree_preload_end (); + *ipp = ip; +return 0 ; + +out_unlock: +write_unlock (&pag->pag_ici_lock); +radix_tree_preload_end (); +out_destroy: +xfs_idestroy (ip); +return error; +} + +/* +* Look up an inode by number in the given file system. +* The inode is looked up in the cache held in each AG. +* If the inode is found in the cache, attach it to the provided +* vnode. +* +* If it is not in core, read it in from the file system's device, +* add it to the cache and attach the provided vnode. +* +* The inode is locked according to the value of the lock_flags parameter. +* This flag parameter indicates how and if the inode's IO lock and inode lock +* should be taken. +* +* mp -- the mount point structure for the current file system. It points +* to the inode hash table. +* tp -- a pointer to the current transaction if there is one. This is +* simply passed through to the xfs_iread() call. +* ino -- the number of the inode desired. This is the unique identifier +* within the file system for the inode being requested. +* lock_flags -- flags indicating how to lock the inode. See the comment +* for xfs_ilock() for a list of valid values. +* bno -- the block number starting the buffer containing the inode, +* if known (as by bulkstat), else 0. +*/ +STATIC int +xfs_iget_core ( +struct inode *inode, +xfs_mount_t *mp, +xfs_trans_t *tp, +xfs_ino_t ino, +uint flags, +uint lock_flags, +xfs_inode_t **ipp, +xfs_daddr_t bno) +{ +xfs_inode_t *ip; +int error; +xfs_perag_t *pag; +xfs_agino_t agino; + +/* the radix tree exists only in inode capable AGs */ +if (XFS_INO_TO_AGNO (mp, ino) >= mp->m_maxagi) +return EINVAL ; + +/* get the perag structure and ensure that it's inode capable */ + pag =xfs_get_perag (mp, ino); +if (!pag->pagi_inodeok) +return EINVAL ; +ASSERT (pag->pag_ici_init); + agino =XFS_INO_TO_AGINO (mp, ino); + +again: + error =0 ; +read_lock (&pag->pag_ici_lock); + ip =radix_tree_lookup (&pag->pag_ici_root, agino); + +if (ip) { + error =xfs_iget_cache_hit (inode, pag, ip, flags, lock_flags); +if (error) + goto out_error_or_again; + }else { +read_unlock (&pag->pag_ici_lock); +XFS_STATS_INC (xs_ig_missed); + + error =xfs_iget_cache_miss (mp, pag, tp, ino, &ip, bno, + flags, lock_flags); +if (error) + goto out_error_or_again; + }xfs_put_perag (mp, pag); - return_ip:ASSERT (ip->i_df.if_ext_max ==XFS_IFORK_DSIZE (ip) /sizeof (xfs_bmbt_rec_t));
@@ -288,6 +315,14 @@ finish_inode:if (ip->i_d.di_mode !=0 )xfs_setup_inode (ip);return 0 ; + +out_error_or_again: +if (error ==EAGAIN ) { +delay (1 ); + goto again; + } +xfs_put_perag (mp, pag); +return error; }
Signature · 1 line
1.5.6
Re: [PATCH 1/3] XFS: factor xfs_iget_core() into hit and miss cases
Quoted 5 lines · Dave Chinner
There are really two cases in
xfs_iget_core(). The first is the cache hit case, the second is the miss case. They share very little code, and hence can easily be factored out into separate functions. This makes the code much easier to understand and subsequently modify.
Looks good.
PATCH 2/3 XFS: Make use of the init-once slab optimisation.
In reply to Dave ChinnerTo avoid having to initialise some fields of the XFS inode on every allocation, we can use the slab init-once feature to initialise them. All we have to guarantee is that when we free the inode, all it's entries are in the initial state. Add asserts where possible to ensure debug kernels check this initial state before freeing and after allocation.
--- fs/xfs/linux-2.6/xfs_super.c | 38 +++++++++++++++++++++++- fs/xfs/xfs_iget.c | 14 --------- fs/xfs/xfs_inode.c | 66 ++++++++++++++++++++++++++++++++++------- fs/xfs/xfs_inode.h | 1 + fs/xfs/xfs_itable.c | 14 ++++---- 5 files changed, 99 insertions(+), 34 deletions(-)
fs/xfs/linux-2.6/xfs_super.c +37 -1
@@ -888,6 +888,42 @@ xfs_fs_inode_init_once(inode_init_once ((struct inode *)vnode); } + +/* +* Slab object creation initialisation for the XFS inode. +* This covers only the idempotent fields in the XFS inode; +* all other fields need to be initialised on allocation +* from the slab. This avoids the need to repeatedly intialise +* fields in the xfs inode that left in the initialise state +* when freeing the inode. +*/ +void +xfs_inode_init_once ( +void *inode) +{ +struct xfs_inode *ip = inode; + +memset (ip,0 ,sizeof (struct xfs_inode )); +atomic_set (&ip->i_iocount,0 ); +atomic_set (&ip->i_pincount,0 ); +spin_lock_init (&ip->i_flags_lock); +INIT_LIST_HEAD (&ip->i_reclaim); +init_waitqueue_head (&ip->i_ipin_wait); + +mrlock_init (&ip->i_lock,MRLOCK_ALLOW_EQUAL_PRI |MRLOCK_BARRIER , +"xfsino" , ip->i_ino); +mrlock_init (&ip->i_iolock,MRLOCK_BARRIER ,"xfsio" , ip->i_ino); + +/* +* Because we want to use a counting completion, complete +* the flush completion once to allow a single access to +* the flush completion without blocking. +*/ +init_completion (&ip->i_flush); +complete (&ip->i_flush); + +} +/* * Attempt to flush the inode, this will actually fail * if the inode is pinned, but we dirty the inode again
@@ -1841,7 +1877,7 @@ xfs_init_zones(void) xfs_inode_zone =kmem_zone_init_flags (sizeof (xfs_inode_t),"xfs_inode" ,KM_ZONE_HWALIGN |KM_ZONE_RECLAIM | -KM_ZONE_SPREAD ,NULL ); +KM_ZONE_SPREAD , xfs_inode_init_once);if (!xfs_inode_zone) goto out_destroy_efi_zone;
fs/xfs/xfs_iget.c +0 -14
@@ -165,20 +165,6 @@ xfs_iget_cache_miss(xfs_itrace_exit_tag (ip,"xfs_iget.alloc" ); -mrlock_init (&ip->i_lock,MRLOCK_ALLOW_EQUAL_PRI |MRLOCK_BARRIER , -"xfsino" , ip->i_ino); -mrlock_init (&ip->i_iolock,MRLOCK_BARRIER ,"xfsio" , ip->i_ino); -init_waitqueue_head (&ip->i_ipin_wait); -atomic_set (&ip->i_pincount,0 ); - -/* -* Because we want to use a counting completion, complete -* the flush completion once to allow a single access to -* the flush completion without blocking. -*/ -init_completion (&ip->i_flush); -complete (&ip->i_flush); -if (lock_flags)xfs_ilock (ip, lock_flags);
fs/xfs/xfs_inode.c +53 -11
95 lines not on this page · raw message
fs/xfs/xfs_inode.h +1 -0
@@ -504,6 +504,7 @@ int xfs_itruncate_finish(struct xfs_trans **, xfs_inode_t *, xfs_fsize_t, int, int);int xfs_iunlink (struct xfs_trans *,xfs_inode_t *); +struct xfs_inode *xfs_inode_alloc (struct xfs_mount *,xfs_ino_t );void xfs_idestroy_fork (xfs_inode_t *,int );void xfs_idestroy (xfs_inode_t *);void xfs_idata_realloc (xfs_inode_t *,int ,int );
fs/xfs/xfs_itable.c +7 -7
@@ -594,21 +594,21 @@ xfs_bulkstat(/* * Get the inode cluster buffer */ -ASSERT (xfs_inode_zone !=NULL ); - ip =kmem_zone_zalloc (xfs_inode_zone, -KM_SLEEP ); - ip->i_ino = ino; - ip->i_mount = mp; -spin_lock_init (&ip->i_flags_lock);if (bp)xfs_buf_relse (bp); + ip =xfs_inode_alloc (mp, ino); +if (!ip) { + bp =NULL ; + rval =ENOMEM ; +break ; + } error =xfs_itobp (mp,NULL , ip, &dip, &bp, bno,XFS_IMAP_BULKSTAT ,XFS_BUF_LOCK );if (!error) clustidx = ip->i_boffset / mp->m_sb.sb_inodesize; -kmem_zone_free (xfs_inode_zone, ip); +xfs_idestroy (ip);if (XFS_TEST_ERROR (error !=0 , mp,XFS_ERRTAG_BULKSTAT_READ_CHUNK ,XFS_RANDOM_BULKSTAT_READ_CHUNK )) {
Signature · 1 line
1.5.6
Re: [PATCH 2/3] XFS: Make use of the init-once slab optimisation.
Quoted 6 lines · Dave Chinner
To avoid having to initialise some fields of the XFS inode on every allocation, we can use the slab init-once feature to initialise them. All we have to guarantee is that when we free the inode, all it's entries are in the initial state. Add asserts where possible to ensure debug kernels check this initial state before freeing and after allocation.
This looks like it's already in:
http://oss.sgi.com/cgi-bin/gitweb.cgi?p=xaiki/xfs-linux-2.6-xfs-cvs/.git;a=commitdiff;h=12efb888674600ce73a64f8c6f4a20ea5e1ce4f1
Re: [PATCH 2/3] XFS: Make use of the init-once slab optimisation.
Quoted 10 lines · Christoph Hellwig
Quoted 6 lines · Dave Chinner
To avoid having to initialise some fields of the XFS inode on every allocation, we can use the slab init-once feature to initialise them. All we have to guarantee is that when we free the inode, all it's entries are in the initial state. Add asserts where possible to ensure debug kernels check this initial state before freeing and after allocation.
This looks like it's already in:
http://oss.sgi.com/cgi-bin/gitweb.cgi?p=xaiki/xfs-linux-2.6-xfs-cvs/.git;a=commitdiff;h=12efb888674600ce73a64f8c6f4a20ea5e1ce4f1
<sigh>
Which means that some of the patches won't apply. SGI folks, can you please get the master tree updated so I can rediff all the patches and repost them again?
Cheers,
Dave.
Signature · 2 lines
Dave Chinner [email protected]
PATCH 3/3 XFS: Never call mark_inode_dirty_sync() directly
In reply to Dave ChinnerOnce the Linux inode and the XFS inode are combined, we cannot rely on just check if the linux inode exists as a method of determining if it is valid or not. Hence we should always call xfs_mark_inode_dirty_sync() instead as it does the correct checks to determine if the liinux inode is in a valid state or not.
--- fs/xfs/linux-2.6/xfs_aops.c | 2 +- fs/xfs/linux-2.6/xfs_iops.c | 2 +- fs/xfs/linux-2.6/xfs_super.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-)
fs/xfs/linux-2.6/xfs_aops.c +1 -1
@@ -191,7 +191,7 @@ xfs_setfilesize( ip->i_d.di_size = isize; ip->i_update_core =1 ; ip->i_update_size =1 ; -mark_inode_dirty_sync (ioend->io_inode); +xfs_mark_inode_dirty_sync (ip); }xfs_iunlock (ip,XFS_ILOCK_EXCL );
fs/xfs/linux-2.6/xfs_iops.c +1 -1
@@ -128,7 +128,7 @@ xfs_ichgtime(if (sync_it) {SYNCHRONIZE (); ip->i_update_core =1 ; -mark_inode_dirty_sync (inode); +xfs_mark_inode_dirty_sync (ip); } }
fs/xfs/linux-2.6/xfs_super.c +1 -1
@@ -949,7 +949,7 @@ xfs_fs_write_inode(* it dirty again so we'll try again later. */ if (error) -mark_inode_dirty_sync (inode); +xfs_mark_inode_dirty_sync (XFS_I (inode));return -error; }
Signature · 1 line
1.5.6
Re: [PATCH 3/3] XFS: Never call mark_inode_dirty_sync() directly
Quoted 5 lines · Dave Chinner
Once the Linux inode and the XFS inode are combined, we cannot rely on just check if the linux inode exists as a method of determining if it is valid or not. Hence we should always call
xfs_mark_inode_dirty_sync()instead as it does the correct checks to determine if the liinux inode is in a valid state or not.
Looks good.