Commit fd9dc93e authored by Matthew Wilcox's avatar Matthew Wilcox
Browse files

XArray: Change xa_insert to return -EBUSY 



Userspace translates EEXIST to "File exists" which isn't a very good
error message for the problem.  "Device or resource busy" is a better
indication of what went wrong.

Signed-off-by: default avatarMatthew Wilcox <willy@infradead.org>
parent 809ab937

Documentation/core-api/xarray.rst

+1 −1
Original line number Diff line number Diff line
@@ -85,7 +85,7 @@ which was at that index; if it returns the same entry which was passed as 


If you want to only store a new entry to an index if the current entry

at that index is ``NULL``, you can use :c:func:`xa_insert` which

returns ``-EEXIST`` if the entry is not empty.

returns ``-EBUSY`` if the entry is not empty.



You can enquire whether a mark is set on an entry by using

:c:func:`xa_get_mark`.  If the entry is not ``NULL``, you can set a mark

fs/nilfs2/btnode.c

+1 −1
Original line number Diff line number Diff line
@@ -189,7 +189,7 @@ retry: 
		 */

		if (!err)

			return 0;

		else if (err != -EEXIST)

		else if (err != -EBUSY)

			goto failed_unlock;



		err = invalidate_inode_pages2_range(btnc, newkey, newkey);

include/linux/xarray.h

+3 −3
Original line number Diff line number Diff line
@@ -664,7 +664,7 @@ static inline void *xa_cmpxchg_irq(struct xarray *xa, unsigned long index, 
 *

 * Context: Any context.  Takes and releases the xa_lock.  May sleep if

 * the @gfp flags permit.

 * Return: 0 if the store succeeded.  -EEXIST if another entry was present.

 * Return: 0 if the store succeeded.  -EBUSY if another entry was present.

 * -ENOMEM if memory could not be allocated.

 */

static inline int xa_insert(struct xarray *xa, unsigned long index,
@@ -693,7 +693,7 @@ static inline int xa_insert(struct xarray *xa, unsigned long index, 
 *

 * Context: Any context.  Takes and releases the xa_lock while

 * disabling softirqs.  May sleep if the @gfp flags permit.

 * Return: 0 if the store succeeded.  -EEXIST if another entry was present.

 * Return: 0 if the store succeeded.  -EBUSY if another entry was present.

 * -ENOMEM if memory could not be allocated.

 */

static inline int xa_insert_bh(struct xarray *xa, unsigned long index,
@@ -722,7 +722,7 @@ static inline int xa_insert_bh(struct xarray *xa, unsigned long index, 
 *

 * Context: Process context.  Takes and releases the xa_lock while

 * disabling interrupts.  May sleep if the @gfp flags permit.

 * Return: 0 if the store succeeded.  -EEXIST if another entry was present.

 * Return: 0 if the store succeeded.  -EBUSY if another entry was present.

 * -ENOMEM if memory could not be allocated.

 */

static inline int xa_insert_irq(struct xarray *xa, unsigned long index,

lib/test_xarray.c

+2 −2
Original line number Diff line number Diff line
@@ -346,7 +346,7 @@ static noinline void check_cmpxchg(struct xarray *xa) 


	XA_BUG_ON(xa, !xa_empty(xa));

	XA_BUG_ON(xa, xa_store_index(xa, 12345678, GFP_KERNEL) != NULL);

	XA_BUG_ON(xa, xa_insert(xa, 12345678, xa, GFP_KERNEL) != -EEXIST);

	XA_BUG_ON(xa, xa_insert(xa, 12345678, xa, GFP_KERNEL) != -EBUSY);

	XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, SIX, FIVE, GFP_KERNEL) != LOTS);

	XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, LOTS, FIVE, GFP_KERNEL) != LOTS);

	XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, FIVE, LOTS, GFP_KERNEL) != FIVE);
@@ -388,7 +388,7 @@ static noinline void check_reserve(struct xarray *xa) 
	/* But xa_insert does not */

	xa_reserve(xa, 12345678, GFP_KERNEL);

	XA_BUG_ON(xa, xa_insert(xa, 12345678, xa_mk_value(12345678), 0) !=

			-EEXIST);

			-EBUSY);

	XA_BUG_ON(xa, xa_empty(xa));

	XA_BUG_ON(xa, xa_erase(xa, 12345678) != NULL);

	XA_BUG_ON(xa, !xa_empty(xa));

lib/xarray.c

+2 −2
Original line number Diff line number Diff line
@@ -1451,7 +1451,7 @@ EXPORT_SYMBOL(__xa_cmpxchg); 
 *

 * Context: Any context.  Expects xa_lock to be held on entry.  May

 * release and reacquire xa_lock if @gfp flags permit.

 * Return: 0 if the store succeeded.  -EEXIST if another entry was present.

 * Return: 0 if the store succeeded.  -EBUSY if another entry was present.

 * -ENOMEM if memory could not be allocated.

 */

int __xa_insert(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)
@@ -1471,7 +1471,7 @@ int __xa_insert(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) 
			if (xa_track_free(xa))

				xas_clear_mark(&xas, XA_FREE_MARK);

		} else {

			xas_set_err(&xas, -EEXIST);

			xas_set_err(&xas, -EBUSY);

		}

	} while (__xas_nomem(&xas, gfp));

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